Arq Bras Cardiol abc Arquivos Brasileiros de Cardiologia Arq. Bras. Cardiol. 0066-782X 1678-4170 Sociedade Brasileira de Cardiologia - SBC 3YZsHZs5VRDzS8DPYXR8mvm S0066-782X2018001600618 10.5935/abc.20180208 Review Article Risk-Benefit Assessment of Carotid Revascularization Oliveira Pedro Piccaro de Vieira José Luiz da Costa Guimarães Raphael Boesche Almeida Eduardo Dytz Savaris Simone Louise Portal Vera Lucia Fundação Universitária de Cardiologia Instituto de Cardiologia Porto Alegre RS Brazil Instituto de Cardiologia - Fundação Universitária de Cardiologia (IC/FUC), Porto Alegre, RS - Brazil Mailing Address: Vera Lucia Portal, Rua Luciana de Abreu, 471 sala 603. Postal Code 90570-080, Moinhos de Vento, Porto Alegre, RS - Brazil. E-mail: veraportal@cardiol.br, editoracao-pc@cardiologia.org.br, veraportal.pesquisa@gmail.com

Author contributions

Conception and design of the research: Oliveira PP, Vieira JLC, Portal VL; Acquisition of data: Oliveira PP, Guimarães RB; Analysis and interpretation of the data: Oliveira PP, Portal VL; Writing of the manuscript: Oliveira PP, Vieira JLC, Guimarães RB, Almeida ED, Savaris SL, Portal VL; Critical revision of the manuscript for intellectual content: Oliveira PP, Vieira JLC, Almeida ED, Savaris SL, Portal VL.

Potential Conflict of Interest

No potential conflict of interest relevant to this article was reported.

 10 2018 111 4 618 625 10 05 2018 21 06 2018 02 07 2018 This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract

Severe carotid atherosclerotic disease is responsible for 14% of all strokes, which result in a high rate of morbidity and mortality. In recent years, advances in clinical treatment of cardiovascular diseases have resulted in a significant decrease in mortality due to these causes.

To review the main studies on carotid revascularization, evaluating the relationship between risks and benefits of this procedure.

The data reviewed show that, for a net benefit, carotid intervention should only be performed in cases of a periprocedural risk of less than 6% in symptomatic patients. The medical therapy significantly reduced the revascularization net benefit ratio for stroke prevention in asymptomatic patients. Real life registries indicate that carotid stenting is associated with a greater periprocedural risk. The operator annual procedure volume and patient age has an important influence in the rate of stroke and death after carotid stenting. Symptomatic patients have a higher incidence of death and stroke after the procedure. Revascularization has the greatest benefit in the first weeks of the event.

There is a discrepancy in the scientific literature about carotid revascularization and/or clinical treatment, both in primary and secondary prevention of patients with carotid artery injury. The identification of patients who will really benefit is a dynamic process subject to constant review.

 Keywords Carotid Artery Diseases Atherosclerosis Endarterectomy, Carotid Stroke Indicators of Morbidity and Mortality Risk Assessment Introduction

Carotid endarterectomy was introduced in 1954 for stroke prevention, but it wasn`t until the 90`s that the first randomized clinical trials (RCTs) evaluated its effectiveness. The first published RCTs on the subject were NASCET (1991), VACS (1991) and ECST (1993), all of which demonstrated benefit of surgical intervention in secondary prevention setting.1-3 Regarding primary prevention, a small RCT was published in 19934 followed by two larger ones (ACAS, 1995; ACST, 2004)5,6 that demonstrated a greater benefit of surgical intervention when compared to optimal medical treatment.

Several studies comparing carotid angioplasty and stenting (CAS) and carotid endarterectomy (CEA) were published in the 2000's, leading to a recommendation for routine use of embolic protection devices. Five clinical trials (SAPPHIRE,7 EVA-3S,8 SPACE,9 CREST10 and ACT I11) found that percutaneous intervention is an alternative to surgical intervention in both symptomatic and asymptomatic patients. On the other hand, the ICSS trial found a higher risk of stroke and death after CAS in symptomatic patients.12 Paraskevas et al.13 compiled data from several “real-world” registries in a systematic review and found that percutaneous procedures resulted in higher rates stroke and death when compared do CEA, albeit with conflicting results from each registry.13

While many studies have focused on comparing the two modalities of intervention, the definition of optimal medical treatment (OMT) has evolved and currently reduces relative risk of stroke related to extracranial atherosclerosis by up to 70%.1,2,10,14

Ascertaining risk-benefit ratio between CAS and CEA is challenging. There are thirty-four international guidelines on the subject, with significant variability regarding choice of carotid revascularization procedure.15 This review aims to provide an updated risk-benefit assessment across the different treatment options (CEA, CAS and OMT) for symptomatic and asymptomatic carotid stenosis.

 Methods

This article was based on a literature review carried out through an online search of the main articles and guidelines published in the last 30 years, aiming to evaluate the relationship between risk and benefit of carotid revascularization. Due to the differences in the indexing processes in the bibliographic databases, we opted for the search for free terms, without the use of controlled vocabulary (descriptors).

 Results

Stroke is the third cause of death in the Western world and the leading cause of permanent neurological disability.16 About 85% of strokes are ischemic in origin and 80% of non-hemorrhagic strokes affect brain areas irrigated by carotid arteries. Most strokes are due to thromboembolism of atherosclerotic lesions in internal carotid arteries. Usually, these occur in smaller carotid plaques with lower than 50% stenosis, considered non-surgical stenosis. The remaining cases are considered stenotic plaques that should be evaluated for surgical treatment.14

Evolution of optimal medical treatment

Pivotal studies on the incidence of stroke in patients with severe symptomatic carotid stenosis, without carotid revascularization, were published in the beginning of the 1990's.1-3 At that time, acetyl salicylic acid was the cornerstone of OMT. In NASCET study, two year stroke incidence was 26% in OMT group, compared to 9% in CEA group.1 In 1995, primary prevention study ACAS5 found a much lower (17.5%) five-year stroke incidence in its OMT group. In 2004, ACST7 reported a further drop of stroke risk to 11.8% (2.4% annually), and by the time 10-year results were reported, in 2010,17 there was an even greater reduction in OMT group (7.2% in the last five years of follow-up). ACST also showed that in those cases of stroke with untreated severe ipsilateral carotid stenosis, OMT reduced stroke risk by almost 70%, resulting in an annual stroke incidence of 0.7% in the last five years of follow-up17 (Table 1).

Evolution of Clinical Treatment<xref ref-type="bibr" rid="B23">23</xref><sup>-</sup><xref ref-type="bibr" rid="B24">24</xref>
Trial Publication Year Annual incidence of stroke in the clinically treated group
ACAS5 1995 3,5%
ACST first 5 years6 2004 2,4%
ACST last 5 years17 2010 1,4%

Stroke risk reduction was followed by a large reduction in myocardial infarction incidence during the same period, which is largely attributable to improvement of OMT and risk factor control.18

A reduction of almost 30% in mortality from atherosclerotic coronary artery disease was reported in Brazil between 1990 and 2009.19 Between 2003 to 2013, mortality rates due to coronary heart disease fell by 38% and the actual number of deaths decreased by 22.9% in the United States.18

Studies with angiotensin-converting enzyme inhibitors (ACE inhibitors) have proved the benefit of this class of drugs on ventricular remodeling, showing also a reduction of 20% in cardiovascular events.20,21 A meta-analysis of more than 30,000 patients demonstrated a protective effect of ACE inhibitors against ischemic events, even in patients without ventricular dysfunction.22 Currently, several guidelines acknowledge the role of these drugs in preventing cardiovascular disease.23-25

Nevertheless, routine use of statins is considered the greatest landmark in OMT. A meta-analysis of 26 RCTs (over 170,000 subjects), published in 2010, demonstrated the efficacy and safety of statins, as well as the correlation between the dose used and the protective effect.26 Two randomized clinical trials reported in 2016 reinforced these findings. The Effect of Statin Treatment on Modifying Plaque Composition (STABLE) study tested high-dose rosuvastatin through a follow-up with intravascular imaging. Besides stabilizing the atherosclerotic plaque, rosuvastatin could also induce some reversal of the atherosclerotic process.27 A second study, Cholesterol Lowering in Intermediate-Risk Persons without Cardiovascular Disease (HOPE 3), demonstrated that routine use of statin in primary prevention subjects with intermediate risk of cardiovascular diseases resulted in 24% reduction in outcomes, including stroke.28

Risks and benefits of intervention

Several international societies indicate carotid intervention in symptomatic patients, ipsilateral stroke or TIA within the previous 6 months, presenting at least 50% extracranial carotid stenosis.15 Considering the great advances in clinical treatment in the last decades, the most important guidelines postulate that the intervention should only be performed when the periprocedural risks are smaller than 6%.15,29-31 (Table 2)

Management of patients with Symptomatic extracranial carotid stenosis<xref ref-type="bibr" rid="B23">23</xref><sup>-</sup><xref ref-type="bibr" rid="B24">24</xref>
Carotid Stenosis Recommendations (Class and Evidence Level)* Periprocedural Risk to maintain clinical benefit
< 50% OMT (IA)
50-59% CEA + OMT (IIaB) < 6%
CAS + OMT (IIbB)
60-69% CEA + OMT (IIaB) < 6%
CAS + OMT (IIbB)
70-99% CEA + OMT (IA) < 6%
CAS + OMT (IIaB)
Occlusion OMT (IA)

OMT: Optimized medical therapy; CEA: Carotid endarterectomy, CAS: Carotid angioplasty and stenting. (Classes of Recommendation: I - The benefit is greater than the risk and the treatment/procedure should be performed or administered; IIa - The benefit is greater than the risk, but further studies are needed, so that it reasonable to perform procedure or administer treatment; IIb - the benefit is equal to or greater than the risk and treatment/procedure may be considered. Levels of Evidence: A - Data derived from multiple randomized clinical trials or meta-analyses; B - Data derived from a single randomized clinical trial or multiple non-randomized studies.)

For all patients: When procedure is indicated, CAS should only be performed if there is a high risk for CEA.

In cases of severe asymptomatic carotid stenosis, the joint guideline of the American Heart Association and American Stroke Association for primary prevention of stroke, published in 2014,30 and the guideline of the European Society of Cardiology, published in 2017,31 recommend that the periprocedural risk should be less than 3% for a net benefit in the revascularization process. (Table 3)

Management of patients with Asymptomatic extracranial carotid stenosis<xref ref-type="bibr" rid="B23">23</xref><sup>-</sup><xref ref-type="bibr" rid="B24">24</xref>
Carotid Stenosis Recommendations (Class and Evidence Level)* Periprocedural Risk to maintain clinical benefit
< 60% OMT (IA)
60-69% OMT (IA); < 3%
CEA + OMT (IIaB) ou CAS + OMT (IIbB)
70-99% OMT (IA) < 3%
CEA + OMT (IIaB) ou CAS + OMT (IIbB)
Occlusion OMT (IA)

OMT: Optimized medical therapy; CEA: Carotid endarterectomy, CAS: Carotid angioplasty and stenting. (Classes of Recommendation: I - The benefit is greater than the risk and the treatment/procedure should be performed or administered; IIa - The benefit is greater than the risk, but further studies are needed, so that it reasonable to perform procedure or administer treatment; IIb - the benefit is equal to or greater than the risk and treatment/procedure may be considered. Levels of Evidence: A - Data derived from multiple randomized clinical trials or meta-analyses; B - Data derived from a single randomized clinical trial or multiple non‑randomized studies.)

For all patients: When procedure is indicated, CAS should only be performed if there is a high risk for CEA.

The risks associated with carotid intervention are heterogeneous, which makes it necessary to separate the patients into subgroups. (Table 4) The first important criterion in the definition of these subgroups is the presence or absence of symptoms, defined by the occurrence of a stroke or a transient ischemic attack (TIA) within the previous six months, affecting the territory supplied by the affected carotid artery.1 The second criterion is based on the definition of high-risk patients for carotid endarterectomy: congestive heart failure, ischemic cardiopathy, the need for associated cardiac surgery, severe pulmonary disease, contralateral carotid artery occlusion, paralysis of recurrent laryngeal nerve, carotid restenosis after procedure, cervical radiotherapy, prior cervical surgeries or age greater than 80 years.32

Risk Subgroups for Carotid Intervention
Subgroup Definition
Symptomatic Occurrence of a stroke or a transient ischemic attack (TIA)within the previous six months, affecting the territory supplied by the affected carotid artery
High-risk for Carotid Endarterectomy Congestive heart failure, ischemic cardiopathy, the need for associated cardiac surgery, severe pulmonary disease, contralateral carotid artery occlusion, paralysis of recurrent laryngeal nerve, carotid restenosis after procedure, cervical radiotherapy, prior cervical surgeries or age greater than 80 years

A systematic review published in 2015 examined the rates of stroke and death after CAS and CEA in twenty-one international records, which together represent more than 1,500,000 procedures performed between 2008 and 2015.13 In asymptomatic patients not at high risk for endarterectomy, carotid stenting had a periprocedural risk lower than 3% in 43% of the cases, and a risk greater than 5% in 14% of the registries. For surgical revascularization in the same group, 95% of the registries reported risks lower than 3%. (Figure 1) In the group of symptomatic patients not at high risk, 72% of the registries after carotid angioplasty showed a greater than 6% incidence of stroke and death in 30 days. On the other hand, only 11% of the registries showed a risk above 6% among the patients submitted to endarterectomy. (Figure 2) Only three of the twenty-one registries analyzed reported data regarding patients with high risk for carotid endarterectomy. In one of them, the rate of events was greater than 3% in asymptomatic patients, for both CAS and CEA. In the group of symptomatic patients, all registries reported rates of stroke and death greater than 6% after CAS and two records showed rates above 6% after carotid endarterectomy.

Percentage of Registries with a Lower than 3% Incidence of Stroke and Death in 30 days after Asymptomatic Carotid Intervention. CAS: Cardiotid angioplasty and stenting; CEA: Carotid endarterectomy. Paraskevas KI, Kalmykov EL, Naylor AR. Stroke/Death Rates Following Carotid Artery Stenting and Carotid Endarterectomy in Contemporary Administrative Dataset Registries: ASystematic Review. Eur J Vasc Endovasc Surg. 2015;51(1):3-12.

Percentage of Registries with a Lower than 6% Incidence of Stroke and Death in 30 days after Symptomatic Carotid Intervention. CAS: Cardiotid angioplasty and stenting; CEA: Carotid endarterectomy. Paraskevas KI, Kalmykov EL, Naylor AR. Stroke/Death Rates Following Carotid Artery Stenting and Carotid Endarterectomy in Contemporary Administrative Dataset Registries: ASystematic Review. Eur J Vasc Endovasc Surg. 2015;51(1):3-12.

Carotid stenting: the age and operator effect

The elderly population usually presents vessel tortuosity and a large burden of atherosclerosis, characteristics that increase complications after angioplasty procedures. Age has been associated with periprocedural stroke and death after CAS, this same finding was not reported after CEA.33 A Cochrane meta-analysis of 16 randomized clinical trials34 and a subanalysis of the CREST trial35 described an association of age ≥ 70 years and increased periprocedural risk after CAS. A meta-analysis of four randomized trials (EVA-3S, SPACE, ICSS and CREST) found that the periprocedural risk of stroke or death after CAS were 3% for patients younger than 60 years and 12% for those older than 70 years, whereas the periprocedural stroke and death risk remained stable at 5% across the entire age spectrum in the CEA group.33

The possibility that the operator is a crucial factor for the good result of the carotid percutaneous intervention was taken into account in the design of the protocols of clinical trials involving CAS. In an attempt to standardize the group of operators, the EVA-3S study8 included only interventionists with a minimum of 12 carotid angioplasties performed previously. The SPACE study9 required a minimum of twenty and five previous procedures. Although most studies report the total volume of procedures performed by the operator, the few ones that specifically addressed this point were not able to show an association between the operator's prior experience and lower rates of complications.36-38

The combined analysis of three large randomized trials (EVA-3S, SPACE and ICSS), published in 2012,39 showed great differences in the incidence of death or stroke when the operators were stratified by annual volume of procedures. Procedures performed by operators with at least six carotid angioplasties per year had an incidence of stroke and death in 30 days of 5.1%, while the procedures performed by those with three or less, showed a 10.1% incidence. It is important to observe that all operators included in the analysis had already performed a minimum number of procedures, i.e., had already surpassed the learning curve. Unlike the annual volume, the total volume of carotid procedures performed during the life of the operator had no association with an increase of complications such as stroke and death, in concordance with other previously published studies.40

Symptomatic patients revascularization - a time sensitive benefit

The results of the main studies with symptomatic patients demonstrate that the greatest benefit of intervention occurs in the first weeks after the index event.41-43 After the first 14 days, there is a rapid decrease in the benefit of the intervention, and more than 70% of the protective effect is seen within the first 30 days; after two years, the symptomatic patient presents the same risk level as the asymptomatic patient.41-43 However, this recommendation has been poorly implemented with less than 20% undergoing revascularization within two weeks the onset of the stroke or TIA.44 A Danish nationwide initiative was able to increase the percentage of CEA within the recommended timeframe from 13% in 2007 to 47% in 2010.45 The evidence of the early procedure safeness is more robust for CEA than for CAS which has conflicting results in different studies.46-48

Secondary prevention is indicated in cases of transient ischemic accident or small strokes, due to the high risk of intracranial hemorrhage when performing carotid intervention in the first few weeks after a major ischemic stroke and to the questionable clinical benefit in the long term.49

Patient with asymptomatic severe carotid lesion

The ACAS study, published in 1995,5 showed that the adjusted risk of stroke and death associated with the intervention was 2.3%, with the endarterectomy preventing 59 cerebral vascular accidents in five years for every 1,000 procedures performed. Despite the very low risk as compared to that observed in practice and to those of the old pharmacological practices, 94% of the CEA were unnecessary. With an adjustment of the periprocedural risk to 0%, eighty-two cerebral vascular accidents would be prevented for every thousand endarterectomies, but still 92% of the patients would be submitted to a procedure without benefits. The same principle can be applied to the 10-year results of the ACST which showed that, with a reduction of the periprocedural risk to 0%, 74 cerebral vascular accidents would be prevented for every thousand endarterectomies, meaning that 93% of the procedures would have been unnecessary.17

The large clinical trials currently conducted have been limited to the comparison between carotid angioplasty and surgery. The lack of a clinical therapy group in the ACT I study, published in 2016, was strongly criticized.50 The new editions of the studies SPACE, SPACE-2 (ISRCTN78592017), CREST and CREST-2 (NCT02089217) planned the inclusion of a third group in clinical therapy, but the SPACE-2 study was suspended by a low rate of inclusions. Presently, the CREST-2 trial has included more than 780 of the 2,480 patients referred.

The current guidelines of the European Society of Cardiology for asymptomatic patients with severe lesions and a moderate surgical risk recommend endarterectomy (Class IIa) in the presence of clinical characteristics and/or imaging results suggestive of an increased risk of late ipsilateral stroke. Angioplasty should be considered (Class IIa) for patients with high risk for endarterectomy, provided that the rates of periprocedural death or stroke are < 3% and the patient's life expectancy is greater than five years, for any one of the groups.31

The population with severe asymptomatic carotid stenosis is not homogeneous. Some lines of research try to identify patients with higher risk through more detailed imaging studies to locate markers of vulnerable plaques and microembolization.51,52 That would allow a more cost-effective carotid revascularization in patients currently classified as asymptomatic.

 Discussion

The present review focuses on the primary and secondary prevention of ischemic stroke through carotid revascularization, which could impact 14% of all cerebral vascular accidents.16

The first studies on this subject were published in the beginning of the 1990's. From the year 2000, studies have focused on the comparison between angioplasty and carotid endarterectomy, without the inclusion of a clinical therapy group for comparison. In this period, there has been significant improvement of clinical treatment and better control of risk factors. The use of acetylsalicylic acid for cardiovascular prevention was already routine decades before a decline in rates of cardiovascular events was observed, suggesting that other classes of drugs are responsible for this change. In the last decades, several studies have shown the impact of statins on cardiovascular outcomes, with a reduction in incidence of up to 50%.26

The data reviewed in the present study show that, for a net benefit of the procedure, carotid intervention should only be performed in cases of a periprocedural risk of less than 6% in symptomatic patients or 3% in asymptomatic patients. A systematic review published in 2015 showed that carotid revascularization is more efficient in symptomatic patients but is associated to a higher incidence of death and stroke. In addition, the results did not show a trend to improved outcomes after carotid stenting between 2008 and 2015, suggesting that this modality of intervention, although less invasive, has higher rates of complications even in patients with high surgical risk.13

The data concerning the effect of operator in CAS show that prior experience is important and can influence the rate of serious complications. A difference of almost 100% in the incidence of 30-day stroke and death outcomes between different groups of operators has already been observed in clinical trials.40 The annual volume of carotid procedures performed by the operator is the factor that best correlated with lower rates of complications.40

The indication for carotid intervention in symptomatic patients showed a greater benefit in the first weeks of the event. In this context, the joint guideline of the American Heart Association and American Stroke Association for prevention of stroke in symptomatic patients, published in 2014, recommends as class IIa that carotid revascularization occurs within two weeks of the index event, if there are no complications that contraindicate the procedure.30 The 2017 guideline of the European Society of Cardiology (ESC Guidelines on the Diagnosis and Treatment of Peripheral Arterial diseases, in collaboration with the European Society for Vascular Surgery), maintained this recommendation.31

The indication for carotid intervention is still questionable in the case of asymptomatic patients, since the studies published up to now have shown a high rate of unnecessary procedures.53 Currently, some studies try to identify asymptomatic patients with higher risk who could undergo a more cost-effective carotid revascularization procedure.

 Conclusion

Severe lesion of the extracranial carotid artery is responsible for 14% of all cerebral vascular accidents. Carotid revascularization has been performed for over 50 years, and several studies have proven that the intervention is capable of preventing this outcome, but with a not inconsiderable risk of serious complications. More recently, carotid angioplasty procedures have broadened the range of invasive options, but the expected reduction in periprocedural risk was not observed. Additionally, the increased incidence of atherosclerosis resulted in a great heterogeneity of patients who are possible candidates for endarterectomy or stenting, and the evolution of pharmacological therapy changed the risk-benefit ratio of intervention in many cases of atherosclerotic disease. Concerning patients treated with the current best medical therapy, carotid intervention should only be performed when it is documented a periprocedural risk of less than 6% in symptomatic patients. Although major guidelines endorse intervention in asymptomatic patients provided that the periprocedural risk is less than 3%, the narrow magnitude of the absolute stroke prevention places carotid intervention as a questionable procedure in an unselected asymptomatic population.

Sources of Funding

There were no external funding sources for this study.

Study Association

This study is not associated with any thesis or dissertation work.

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De Padua A Favarato D Original article mortality due to cardiovascular diseases in Brazil and in the metropolitan region of São Paulo : A 2011 Update Arq Bras Cardiol 2012 2 99 755 761 20 Rutherford JD, Pfeffer MA, Moye LA, Davis BR, Flaker GC, Kawey PR, et al. Effects of captopril on ischemic events after myocardial infarction: results of the Survival and Ventricular enlargement trial-SAVE Investigators. Circulation. 1994;90:1731-8. Rutherford JD Pfeffer MA Moye LA Davis BR Flaker GC Kawey PR Effects of captopril on ischemic events after myocardial infarction: results of the Survival and Ventricular enlargement trial-SAVE Investigators Circulation 1994 90 1731 1738 21 Yusuf S, Pepine CJ, Garces C, Pouler H, Salem D, Kostis J, et al. Effect of enalapril on myocardial infarction and unstable angina in patients with low ejection fractions. Lancet. 1992;340(8829):1173-8. Yusuf S Pepine CJ Garces C Pouler H Salem D Kostis J Effect of enalapril on myocardial infarction and unstable angina in patients with low ejection fractions Lancet 1992 340 8829 1173 1178 22 Al-Mallah MH, Tleyjeh IM, Abdel-Latif AA, Weaver WD. Angiotensin-Converting Enzyme Inhibitors in Coronary Artery Disease and Preserved Left Ventricular Systolic Function. A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Am Coll Cardiol. 2006;47(8):1576-83. Al-Mallah MH Tleyjeh IM Abdel-Latif AA Weaver WD Angiotensin-Converting Enzyme Inhibitors in Coronary Artery Disease and Preserved Left Ventricular Systolic Function. A Systematic Review and Meta-Analysis of Randomized Controlled Trials J Am Coll Cardiol 2006 47 8 1576 1583 23 Montalescot G, Sechtem U, Achenbach S, Achenbach S, Andreotti F, Arden C, et al. et al. 2013 ESC guidelines on the management of stable coronary artery disease: the Task Force on the management of stable coronary artery disease of the European Society of Cardiology. Eur Heart J. 2013;34(38):2949-3003. Montalescot G Sechtem U Achenbach S Achenbach S Andreotti F Arden C 2013 ESC guidelines on the management of stable coronary artery disease: the Task Force on the management of stable coronary artery disease of the European Society of Cardiology Eur Heart J 2013 34 38 2949 3003 24 Fihn SD, Gardin JM, Abrams J, Berra K, Blankenship JC, Dallas AP, et al. 2012 ACCF/AHA Guideline for the diagnosis and management of patients with stable ischemic heart disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, and the American College of Ph. J Am Coll Cardiol. 2012;60(24):e44-e164. Fihn SD Gardin JM Abrams J Berra K Blankenship JC Dallas AP 2012 ACCF/AHA Guideline for the diagnosis and management of patients with stable ischemic heart disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, and the American College of Ph J Am Coll Cardiol 2012 60 24 e44 e164 25 Cesar LA, Ferreira JF,Armaganijan D, Gowdak LH, Mansur AP, Bodanese L,C; Sociedade Brasileira de Cardiologia. Diretriz de doença coronária estável. Arq Bras Cardiol. 2014;103(supl 2):1-59. Cesar LA Ferreira JF Armaganijan D Gowdak LH Mansur AP Bodanese L,C Sociedade Brasileira de Cardiologia Diretriz de doença coronária estável Arq Bras Cardiol 2014 103 supl 2 1 59 26 Cholesterol Treatment Triallists(CTT) Collaboration, Baigent C, Blackwell L, Emberson J, Holland J, Reith C, et al. Efficacy and safety of more intensive lowering of LDL cholesterol: A meta-analysis of data from 170 000 participants in 26 randomised trials. Lancet. 2010;376(9753):1670-81. Cholesterol Treatment Triallists(CTT) Collaboration Baigent C Blackwell L Emberson J Holland J Reith C Efficacy and safety of more intensive lowering of LDL cholesterol: A meta-analysis of data from 170 000 participants in 26 randomised trials Lancet 2010 376 9753 1670 1681 27 Park SJ, Kang SJ, Ahn JM, Chang M, Yun SC, Roh JH, et al. Effect of Statin Treatment on Modifying Plaque Composition A Double-Blind, Randomized Study. J Am Coll Cardiol. 2016;67(15):1772-83. Park SJ Kang SJ Ahn JM Chang M Yun SC Roh JH Effect of Statin Treatment on Modifying Plaque Composition A Double-Blind, Randomized Study J Am Coll Cardiol 2016 67 15 1772 1783 28 Yusuf S, Bosch J, Dagenais G, Zhu J, Xavier D, Liu L, et al. Cholesterol Lowering in Intermediate-Risk Persons without Cardiovascular Disease. N Engl J Med. 2016;374(21):2012-31. Yusuf S Bosch J Dagenais G Zhu J Xavier D Liu L Cholesterol Lowering in Intermediate-Risk Persons without Cardiovascular Disease N Engl J Med 2016 374 21 2012 2031 29 Brott TG, Halperin JL, Abbara S, Bacharach JM, Barr JD, Bush RL, et al. Guideline on the management of patients with extracranial carotid and vertebral artery disease. Vasc Med. 2011;16(1):35-77. Brott TG Halperin JL Abbara S Bacharach JM Barr JD Bush RL Guideline on the management of patients with extracranial carotid and vertebral artery disease Vasc Med 2011 16 1 35 77 30 Kernan WN, Ovbiagele B, Black HR, Bravata DM, Chimowitz MI, Ezekowitz MD, et al. Guidelines for the Prevention of Stroke in Patients with Stroke and Transient Ischemic Attack: A Guideline for Healthcare Professionals from the American Heart Association/American Stroke Association. Stroke. 2014;45(7):2160-236. Kernan WN Ovbiagele B Black HR Bravata DM Chimowitz MI Ezekowitz MD Guidelines for the Prevention of Stroke in Patients with Stroke and Transient Ischemic Attack: A Guideline for Healthcare Professionals from the American Heart Association/American Stroke Association Stroke 2014 45 7 2160 2236 31 Aboyans V, Ricco J-B, Bartelink M-L, Bjorck M, Brodmann M, Cohnert T, et al. 2017 ESC Guidelines on the Diagnosis and Treatment of Peripheral Arterial Diseases, in collaboration with the European Society for Vascular Surgery (ESVS). Eur Heart J. 2018; 39(9):763-816. Aboyans V Ricco J-B Bartelink M-L Bjorck M Brodmann M Cohnert T 2017 ESC Guidelines on the Diagnosis and Treatment of Peripheral Arterial Diseases, in collaboration with the European Society for Vascular Surgery (ESVS) Eur Heart J 2018 39 9 763 816 32 Gurm HS, Yadav JS, Fayad P, Katzen BT, Mishkel GJ, Bajwa TK, et al. Long-term results of carotid stenting versus endarterectomy in high-risk patients. N Engl J Med. 2008;358(15):1572-9. Gurm HS Yadav JS Fayad P Katzen BT Mishkel GJ Bajwa TK Long-term results of carotid stenting versus endarterectomy in high-risk patients N Engl J Med 2008 358 15 1572 1572 33 Howard G, Roubin GS, Jansen O, Hendrikse J, Halliday A, Froecrich G, et al. Association between age and risk of stroke or death from carotid endarterectomy and carotid stenting: A meta-analysis of pooled patient data from four randomised trials. Lancet. 2016;387(10025):1305-11. Howard G Roubin GS Jansen O Hendrikse J Halliday A Froecrich G Association between age and risk of stroke or death from carotid endarterectomy and carotid stenting: A meta-analysis of pooled patient data from four randomised trials Lancet 2016 387 10025 1305 1311 34 Bonati LH, Lyrer P, Ederle J, Featherstone R, Brown MM. Percutaneous transluminal balloon angioplasty and stenting for carotid artery stenosis. Cochrane Database Syst Rev. 2012;12(9):CD000515. Bonati LH Ederle J Featherstone R Brown MM Percutaneous transluminal balloon angioplasty and stenting for carotid artery stenosis Cochrane Database Syst Rev 2012 12 9 CD000515 35 Voeks JH, Howard G, Roubin GS,Malas MB, Cohen DJ, Sternbergh WC, et al. Age and outcomes after carotid stenting and endarterectomy: The Carotid Revascularization Endarterectomy Versus Stenting Trial. Stroke. 2011. 42(12):B484-90. Voeks JH Howard G Roubin GS Malas MB Cohen DJ Sternbergh WC Age and outcomes after carotid stenting and endarterectomy: The Carotid Revascularization Endarterectomy Versus Stenting Trial Stroke 2011 42 12 B484 B490 36 Gray WA, Rosenfield KA, Jaff MR, Chaturvedi S, Peng L, Verta P, et al. Influence of site and operator characteristics on carotid artery stent outcomes: analysis of the CAPTURE 2 (Carotid ACCULINK/ACCUNET Post Approval Trial to Uncover Rare Events) clinical study. JACC Cardiovasc Interv. 2011;4(2):235-46. Gray WA Rosenfield K A Jaff MR Chaturvedi S Peng L Verta P Influence of site and operator characteristics on carotid artery stent outcomes: analysis of the CAPTURE 2 (Carotid ACCULINK/ACCUNET Post Approval Trial to Uncover Rare Events) clinical study JACC Cardiovasc Interv 2011 4 2 235 246 37 Nallamothu BK, Gurm HS, Ting HH, Goodney PP, Rogers MA, Curtis JP, et al. Operator experience and carotid stenting outcomes in Medicare beneficiaries. JAMA. 2011;306(12):1338-43. Nallamothu BK Gurm HS Ting HH Goodney PP Rogers MA Curtis JP Operator experience and carotid stenting outcomes in Medicare beneficiaries JAMA 2011 306 12 1338 1343 38 Fiehler J, Jansen O, Berger J, Eckstein H-H, Ringleb PA, Stingele R. Differences in complication rates among the centres in the SPACE study. Neuroradiology. 2008;50(12):1049-53. Fiehler J Jansen O Berger J Eckstein H-H Ringleb PA Stingele R Differences in complication rates among the centres in the SPACE study Neuroradiology 2008 50 12 1049 1053 39 Calvet D, Mas JL, Algra A, Becquemin JP, Bonati LH, Dobson J, et al. Carotid stenting is there an operator effect? A pooled analysis from the carotid stenting trialists' collaboration. Stroke. 2014;45(2):527-32. Calvet D Mas JL Algra A Becquemin JP Bonati LH Dobson J Carotid stenting is there an operator effect? A pooled analysis from the carotid stenting trialists' collaboration Stroke 2014 45 2 527 532 40 Lin PH, Bush RL, Peden EK, Zhou W, Guerrero M, Henao EA, et al. Carotid artery stenting with neuroprotection: assessing the learning curve and treatment outcome. Am J Surg. 2005;190(6):850-7. Lin PH Bush RL Peden EK Zhou W Guerrero M Henao EA Carotid artery stenting with neuroprotection: assessing the learning curve and treatment outcome Am J Surg 2005 190 6 850 857 41 Rerkasem K, Rothwell PM. Carotid endarterectomy for symptomatic carotid stenosis. Cochrane Database Syst Rev. 2011;(4):CD001081. Rerkasem K Rothwell PM Carotid endarterectomy for symptomatic carotid stenosis Cochrane Database Syst Rev 2011 4 CD001081 42 Rerkasem K, Rothwell PM. Systematic review of the operative risks of carotid endarterectomy for recently symptomatic stenosis in relation to the timing of surgery. Stroke. 2009;40(10):e564-12. Rerkasem K Rothwell PM Systematic review of the operative risks of carotid endarterectomy for recently symptomatic stenosis in relation to the timing of surgery Stroke 2009 40 10 e564 e512 43 Rothwell PM, Eliasziw M, Gutnikov SA, Warlow CP, Barnett HJM. Endarterectomy for symptomatic carotid stenosis in relation to clinical subgroups and timing of surgery. Lancet. 2004;363(9413):915-24. Rothwell PM Eliasziw M Gutnikov SA Warlow CP Barnett HJM Endarterectomy for symptomatic carotid stenosis in relation to clinical subgroups and timing of surgery Lancet 2004 363 9413 915 924 44 Halliday AW, Lees T, Kamugasha D, Waiting times for carotid endarterectomy in UK: Observational study. BMJ. 2009 Jun 4; 338:1847. Halliday AW Lees T Kamugasha D Waiting times for carotid endarterectomy in UK: Observational study BMJ 04 06 2009 338 1847 1847 45 Witt AH, Johnsen SP, Jensen LP, Hansen AK, Hundborg HH, Andersen G. Reducing delay of carotid endarterectomy in acute ischemic stroke patients: a nationwide initiative. Stroke; 2013;44(3):686-90. Witt AH Johnsen SP Jensen LP Hansen AK Hundborg HH Andersen G Reducing delay of carotid endarterectomy in acute ischemic stroke patients: a nationwide initiative Stroke 2013 44 3 686 690 46 Wabnitz AM, Turan TN. Symptomatic Carotid Artery Stenosis: Surgery, Stenting, or Medical Therapy? Curr Treat Options Cardiovasc Med. 2017;19(8):62. Wabnitz AM Turan TN Symptomatic Carotid Artery Stenosis: Surgery, Stenting, or Medical Therapy? Curr Treat Options Cardiovasc Med 2017 19 8 62 62 47 Liu H, Chu J, Zhang L, Liu C, Yan Z, Zhou S. Clinical comparison of outcomes of early versus delayed carotid artery stenting for symptomatic cerebral watershed infarction due to stenosis of the proximal internal carotid artery. Biomed Res Int. 2016;2016:6241546. Liu H Chu J Zhang L Liu C Yan Z Zhou S Clinical comparison of outcomes of early versus delayed carotid artery stenting for symptomatic cerebral watershed infarction due to stenosis of the proximal internal carotid artery Biomed Res Int 2016 2016 6241546 6241546 48 Song KS, Kwon O-K, Hwang G, Bae HJ, Han MK, Kim BJ, et al. Early carotid artery stenting for symptomatic carotid artery stenosis. Acta Neurochir (Wien). 2015;157(11):1873-8. Song KS Kwon O-K Hwang G Bae HJ Han MK Kim BJ Early carotid artery stenting for symptomatic carotid artery stenosis Acta Neurochir (Wien) 2015 157 11 1873 1878 49 Barbetta I, Carmo M, Mercandalli G, Lattuada P, Mazzacaro D, Settembrini AM, et al. Outcomes of urgent carotid endarterectomy for stable and unstable acute neurologic deficits. J Vasc Surg. 2014;54(2):440-6. Barbetta I Carmo M Mercandalli G Lattuada P Mazzacaro D Settembrini AM Outcomes of urgent carotid endarterectomy for stable and unstable acute neurologic deficits J Vasc Surg 2014 54 2 440 446 50 Rosenfield K, Matsumura JS, Chaturvedi S, Reles I, Ansel GM, Metzger DC, et al. et al. Randomized Trial of Stent versus Surgery for Asymptomatic Carotid Stenosis. N Engl J Med. 2016;374(11):904-20. Rosenfield K Matsumura JS Chaturvedi S Reles I Ansel GM Metzger DC Randomized Trial of Stent versus Surgery for Asymptomatic Carotid Stenosis N Engl J Med 2016 374 11 904 920 51 Markus HS, King A, Shipley M, Topakian R, Cullinane M, Reihill S, et al. Asymptomatic embolisation for prediction of stroke in the Asymptomatic Carotid Emboli Study (ACES): a prospective observational study. Lancet Neurol. 2010;9(7):663-71. Markus HS King A Shipley M Topakian R Cullinane M Reihill S Asymptomatic embolisation for prediction of stroke in the Asymptomatic Carotid Emboli Study (ACES): a prospective observational study Lancet Neurol 2010 9 7 663 671 52 Naylor AR, Sillesen H, Schroeder T V. Clinical and imaging features associated with an increased risk of early and late stroke in patients with symptomatic carotid disease. Eur J Vasc Endovasc Surg. 2015;49(5):513-23. Naylor AR Sillesen H Schroeder T V Clinical and imaging features associated with an increased risk of early and late stroke in patients with symptomatic carotid disease Eur J Vasc Endovasc Surg 2015 49 5 513 523 53 Naylor AR, Gaines PA, Rothwell PM. Who benefits most from intervention for asymptomatic carotid stenosis: patients or professionals? Eur J Vasc Endovasc Surg. 2009;37(6):625-32. Naylor AR Gaines PA Rothwell PM Who benefits most from intervention for asymptomatic carotid stenosis: patients or professionals? Eur J Vasc Endovasc Surg 2009 37 6 625 632 Artigo de Revisão Avaliação do Risco-Benefício da Revascularização Carotídea Oliveira Pedro Piccaro de Vieira José Luiz da Costa Guimarães Raphael Boesche Almeida Eduardo Dytz Savaris Simone Louise 2 Portal Vera Lucia Instituto de Cardiologia - Fundação Universitária de Cardiologia (IC/FUC), Porto Alegre, RS - Brasil Correspondência: Vera Lucia Portal, Rua Luciana de Abreu, 471 sala 603. CEP 90570-080, Moinhos de Vento, Porto Alegre, RS - Brasil. E-mail: veraportal@cardiol.br, editoracao-pc@cardiologia.org.br, veraportal.pesquisa@gmail.com

Contribuição dos autores

Concepção e desenho da pesquisa: Oliveira PP, Vieira JLC, Portal VL; Obtenção de dados: Oliveira PP, Guimarães RB; Análise e interpretação dos dados: Oliveira PP, Portal VL; Redação do manuscrito: Oliveira PP, Vieira JLC, Guimarães RB, Almeida ED, Savaris SL, Portal VL; Revisão crítica do manuscrito quanto ao conteúdo intelectual importante: Oliveira PP, Vieira JLC, Almeida ED, Savaris SL, Portal VL.

Potencial conflito de interesses

Declaro não haver conflito de interesses pertinentes.

 Resumo

A doença aterosclerótica carotídea grave é responsável por 14% de todos os acidentes vasculares cerebrais (AVC), que refletem em uma alta taxa de morbimortalidade. Nos últimos anos, os avanços no tratamento clínico das doenças cardiovasculares geraram um decréscimo importante na mortalidade por estas causas.

Revisar principais estudos que dizem respeito à revascularização carotídea avaliando a relação entre risco e beneficio deste procedimento.

Os dados encontrados indicam que o procedimento só deve ser realizado se houver um risco periprocedimento menor que 6% em pacientes sintomáticos para que haja beneficio líquido na intervenção carotídea. O tratamento clínico reduziu significativamente o benefício líquido da revascularização na prevenção de AVC em pacientes assintomáticos. Registros que refletem a prática diária demonstram que a angioplastia carotídea esta associada a um risco periprocedimento mais elevado. O volume anual de procedimentos por operador e a idade dos pacientes têm uma importante influência nas taxas de AVC e morte pós angioplastia. Pacientes sintomáticos têm uma maior incidência de AVC e morte após procedimento. A revascularização tem o maior benefício nas primeiras semanas do evento.

Existem discrepâncias na literatura científica com relação à revascularização carotídea e/ou tratamento clínico, tanto na prevenção primária quanto secundária de pacientes com lesão carotídea. A identificação do paciente que realmente será beneficiado é um processo dinâmico sujeito a constante revisão.

 Palavras-chave Doenças das Artérias Carótidas Aterosclerose Endarterectomia das Carótidas Acidente Vascular Cerebral (AVC) Indicadores de Morbimortalidade Medição de Risco Introdução

A endarterectomia carotídea foi introduzida em 1954 para prevenção de acidente vascular cerebral, mas foi somente na década de 90 que os primeiros ensaios clínicos randomizados (ECR) avaliaram sua eficácia. Os primeiros ECRs publicados sobre o assunto foram o NASCET (1991), o VACS (1991) e o ECST (1993), todos os quais demonstraram o grande benefício da intervenção cirúrgica no cenário de prevenção secundária.1-3 Quanto à prevenção primária, um ECR pequeno foi publicado em 19934 seguido por dois mais extensos (ACAS, 1995; ACST, 2004)5,6 que demonstraram um benefício maior da intervenção cirúrgica comparado a tratamento médico ótimo.

Diversos estudos comparando angioplastia e stent carotídeos (CAS) e endarterectomia carotídea (CEA) foram publicados nos anos 2000, levando a uma recomendação de uso rotineiro de dispositivos de proteção embólica. Cinco ensaios clínicos (SAPPHIRE,7 EVA-3S,8 SPACE,9 CREST10 e ACT I11) demonstraram que intervenção percutânea é uma alternativa a intervenção cirúrgica tanto em pacientes sintomáticos, quanto nos assintomáticos. Por outro lado, o ensaio ICSS demonstrou um risco mais alto de acidente vascular cerebral após CAS em pacientes sintomáticos.12 Paraskevas at al.,13 compilaram dados de diversos registros do “mundo real” em uma análise sistemática e observou que procedimentos percutâneos resultaram em maiores taxas de acidente vascular cerebral e morte se comparados à CEA, embora com resultados conflitantes entre cada registro.13

Enquanto diversos estudos têm focado na comparação das duas modalidades de intervenção, a definição de tratamento médico ótimo (OMT) evoluiu e atualmente reduz o risco relativo de acidente vascular cerebral relacionado a aterosclerose extracraniana em torno de até 70%.1,2,10,14

É um desafio determinar a proporção risco-benefício entre CAS e CEA. Há trinta e quatro diretrizes internacionais a esse respeito, com uma variabilidade significativa quanto à escolha do procedimento de revascularização carotídea.15 Esta análise tem por objetivo fornecer uma avaliação atualizada de risco-benefício através das diferentes opções de tratamento (CEA, CAS e OMT) para estenose carotídea sintomática e assintomática.

 Métodos

Este artigo foi baseado numa análise de literatura realizada através de pesquisa online nos principais artigos e diretrizes publicados nos últimos 30 anos, com o propósito de avaliar a relação entre o risco e o benefício da revascularização carotídea. Devido às diferenças no processo de indexação nas bases de dados bibliográficas, optamos pela busca de termos livres, sem o uso de vocabulário controlado (descritores).

 Resultados

Acidente vascular cerebral é a terceira causa de morte no mundo ocidental e a maior causa de deficiência neurológica permanente.16 Cerca de 85% dos acidentes vasculares cerebrais são isquêmicos em origem e 80% dos acidentes vasculares cerebrais não-hemorrágicos afetam áreas cerebrais irrigadas pelas artérias carótidas. A maioria dos acidentes vasculares cerebrais ocorrem devido a embolia de lesões ateroscleróticas das artérias carótidas internas. Geralmente, elas ocorrem em placas carotídeas menores com menos de 50% de estenose considerada estenose não-cirúrgica. Os casos remanescentes são considerados placas estenóticas que devem ser avaliadas para tratamento cirúrgico.14

Evolução do Tratamento Médico Ótimo

Os principais estudos sobre a incidência de acidente vascular cerebral em pacientes com estenose cardíaca sintomática grave, sem revascularização carotídea, foram publicados no início da década de 1990.1-3 Naquela época, o acido acetilsalicílico era a pedra fundamental do OMT. No estudo de NASCET, a incidência de acidente vascular cerebral em dois anos ocorreu em 26% no grupo OMT, comparado a 9% no grupo CEA.1 Em 1995, O estudo de prevenção primária ACAS5 encontrou uma incidência muito mais baixa (17.5%) de acidente vascular cerebral de cinco anos em seu grupo OMT. Em 2004, o ACST7 relatou uma queda maior de risco de acidente vascular cerebral para 11,8% (2,4% anualmente), e quando os resultados de 10 anos foram relatados, em 2010,17 houve uma redução ainda maior no grupo OMT (7,2% nos últimos cinco anos de acompanhamento). O ACST também mostrou que naqueles casos de acidente vascular cerebral com estenose carotídea ipsilateral grave não-tratada, o OMT reduziu o risco de acidente vascular cerebral em quase 70%, resultando em incidência anual de acidente vascular cerebral de 0,7% nos últimos cinco anos de acompanhamento17 (Tabela 1).

Evolução de tratamento clínico<xref ref-type="bibr" rid="B23">23</xref><sup>-</sup><xref ref-type="bibr" rid="B24">24</xref>
Ensaio Ano de Publicação Incidência anual de AVC no grupo tratado clinicamente
ACAS5 1995 3,5%
ACST primeiros 5 anos6 2004 2,4%
ACST últimos 5 anos17 2010 1,4%

AVC: acidente vascular cerebral.

A redução do risco de acidente vascular cerebral foi acompanhada por uma grande redução na incidência de infarto do miocárdio durante o mesmo período, o que é amplamente atribuível à melhoria do OMT e controle dos fatores de risco.18

No Brasil, foi relatada uma redução de quase 30% na mortalidade por doença arterial coronariana aterosclerótica entre 1990 e 2009.19 Nos Estados unidos, as taxas de mortalidade devido a doença coronária caíram 38% e o número real de mortes diminuiu 22,9% nos entre 2003 e 2013.18

Estudos com inibidores da enzima conversora de angiotensina (inibidores da ECA) têm provado o benefício dessa classe de drogas no remodelamento ventricular, também mostrando uma redução de 20% e eventos cardiovasculares.20,21 Uma meta-análise de mais de 30.000 pacientes demonstrou um efeito protetivo dos inibidores da ECA contra eventos isquêmicos, mesmo em pacientes sem disfunção ventricular.22 Atualmente, diversas diretrizes reconhecem o papel dessas drogas na prevenção de doenças cardiovasculares.23-25

No entanto, o uso rotineiro de estatinas é considerado o maior de todos os marcos em OMT. Uma meta-análise de 26 RCTs (mais de 170.000 indivíduos), publicado em 2010, demonstrou a eficácia e a segurança das estatinas, bem com a correlação entre a dose usada e o efeito protetivo.26

Dois ensaios clínicos randomizados relatados em 2016 reforçaram essas descobertas. O estudo Efeito do Tratamento por Estatina na Modificação da Composição da Placa (Effect of Statin Treatment on Modifying Plaque Composition - STABLE, em inglês) testou rosuvastatina de alta dosagem através de um acompanhamento com imagem intravascular. Além de estabilizar a placa aterosclerótica, a rosuvastatina ainda induziu alguma reversão do processo aterosclerótico.27 Um segundo estudo, redução do Colesterol em Pessoas de Risco Intermediário sem Doença Cardiovascular (Cholesterol Lowering in Intermediate-Risk Persons without Cardiovascular Disease - HOPE 3), demonstrou que o uso rotineiro de estatina em indivíduos em prevenção primaria com risco intermediário de doenças cardiovasculares resultou em redução nos desfechos, incluindo acidente vascular cerebral.28

Riscos e Benefícios da Intervenção

Diversas sociedades internacionais indicam intervenção carotídea em pacientes sintomáticos, com acidente vascular cerebral ipsilateral ou TIA dentro dos 6 meses anteriores, apresentando pelo menos 50% de estenose carotídea extracranial.15 Tendo em mente os grandes avanços em tratamento clínico das últimas décadas, as diretrizes mais importantes postulam que a intervenção apenas deveria ser realizada quando os riscos periprocedimentais foram menores do que 6%.15,29-31 (Tabela 2)

Gestão de pacientes com estenose carotídea extracraniana sintomática<xref ref-type="bibr" rid="B23">23</xref><sup>-</sup><xref ref-type="bibr" rid="B24">24</xref>
Estenose Carotídea Recomendações (Classe e Nível de Evidência)* Risco Periprocedimental para manter o benefício clínico
< 50% OMT (IA)
50-59% CEA + OMT (IIaB) < 6%
CAS + OMT (IIbB)
60-69% CEA + OMT (IIaB) < 6%
CAS + OMT (IIbB)
70-99% CEA + OMT (IA) < 6%
CAS + OMT (IIaB)
Oclusão OMT (IA)

OMT: Terapia médica otimizada; CEA: endarterectomia carotídea, CAS: angioplastia e stent carotídeo. (Classes de Recomendação: I - O benefício é maior do que o risco e o tratamento/procedimento deve ser realizado ou administrado; IIa - O benefício é maior do que o risco, mas são necessários mais estudos, então é razoável realizar o procedimento ou administrar tratamento; IIb - O benefício é maior ou igual ao que o risco e o tratamento/procedimento pode ser considerado. Níveis de Evidência: A - Dados derivados de diversos ensaios clínicos randomizados ou meta-análises; B - Dados derivados de um único ensaio clínico randomizados ou múltiplos estudos não-randomizados.)

Para todos os pacientes: Quando o procedimento é indicado, a CAS apenas deve ser realizada se houver um risco alto para a CEA.

Em casos em que há estenose carotídea grave assintomática, a diretriz comum da American Heart Association e American Stroke Association para prevenção primária do acidente vascular cerebral, publicada em 2014,30 e a diretriz da Sociedade Européia de Cardiologia (European Society of Cardiology), publicada em 2017,31 recomendam que o risco periprocedimental seja inferior a 3% para um benefício líquido no processo de revascularização. (Tabela 3)

Gestão de pacientes com estenose carotídea extracraniana assintomática<xref ref-type="bibr" rid="B23">23</xref><sup>-</sup><xref ref-type="bibr" rid="B24">24</xref>
Estenose Carotídea Recomendações (Classe e Nível de Evidência)* Risco Periprocedimental para manter o benefício clínico
< 60% OMT (IA)
60-69% OMT (IA); < 3%
CEA + OMT (IIaB) ou CAS + OMT (IIbB)
70-99% OMT (IA) < 3%
CEA + OMT (IIaB) ou CAS + OMT (IIbB)
Oclusão OMT (IA)

OMT: Terapia médica otimizada; CEA: endarterectomia carotídea, CAS: angioplastia e stent carotídeo. (Classes de Recomendação: I - O benefício é maior do que o risco e o tratamento/procedimento deve ser realizado ou administrado; IIa - O benefício é maior do que o risco, mas são necessários mais estudos, então é razoável realizar o procedimento ou administrar tratamento; IIb - O benefício é maior ou igual ao que o risco e o tratamento/procedimento pode ser considerado. Níveis de Evidência: A - Dados derivados de diversos ensaios clínicos randomizados ou meta-análises; B - Dados derivados de um único ensaio clínico randomizados ou múltiplos estudos não-randomizados.)

Para todos os pacientes: Quando o procedimento é indicado, a CAS apenas deve ser realizada se houver um risco alto para a CEA.

Os riscos associados à intervenção carotídea são heterogêneos, o que torna necessário separar os pacientes em subgrupos. (Tabela 4) O primeiro critério importante na definição desses subgrupos é a presença ou ausência de sintomas, definidos pela ocorrência de um acidente vascular cerebral ou um ataque isquêmico transitório (TIA) dentro dos seis meses anteriores, afetando o território fornecido pela artéria carótida afetada.1 O segundo critério é baseado na definição de pacientes de alto risco para endarterectomia carotídea: insuficiência cardíaca congestiva, cardiopatia isquêmica, a necessidade de cirurgia cardíaca associada, doença pulmonar grave, oclusão da artéria carótida contralateral, paralisia do nervo laríngeo recorrente, restenose carotídea após procedimento, radioterapia cervical, cirurgias cervicais anteriores ou idade acima de 80 anos.32

Subgrupos de Risco para Intervenção Carotídea
Subgrupo Definição
Sintomático Ocorrência de acidente vascular cerebral ou um ataque isquêmico transitório (TIA) dentro dos seis meses anteriores, afetando o território fornecido pela artéria carótida afetada.
Alto Risco de Endarterectomia Carotídea Insuficiência cardíaca congestiva, cardiopatia isquêmica, necessidade de cirurgia cardíaca associada, doença pulmonar grave, oclusão da artéria carótida contralateral, paralisia do nervo laríngeo recorrente, reestenose carotídea pós-procedimento, radioterapia cervical, cirurgias cervicais prévias ou idade acima de 80 anos

Uma análise sistemática publicada em 2015 examinou as taxas de acidente vascular cerebral e morte após CAS e CEA em vinte e um registros internacionais, que conjuntamente representam mais de 1.500.000 procedimentos realizados entre 2008 e 2015.13 Em pacientes assintomáticos sem alto risco de endarterectomia, stent carotídeo apresentou um risco procedimental abaixo de 3% em 43% dos casos, e risco acima de 5% em 14% dos registros. Quanto a revascularização cirúrgica no mesmo grupo, 95% dos registros relataram riscos abaixo de 3% (Figura 1). No grupo de pacientes sintomáticos sem alto risco, 72% dos registros após angioplastia carotídea mostraram uma incidência de acidente vascular cerebral e morte em 30 dias acima de 6%. Por outro lado, apenas 11% dos registros mostraram um risco acima de 6% entre os pacientes submetidos a endartectomia. (Figura 2) Apenas três dos vinte e um registros analisados relataram dados acerca de pacientes sob alto risco para endarterectomia carotídea. Em um deles, a taxa de eventos foi acima de 3% em pacientes assintomáticos, tanto para CAS, quanto para CEA. No grupo de pacientes sintomáticos, todos os registros relataram taxas de acidente vascular cerebral e morte acima de 6% após CAS e dois registros mostraram taxas acima de 6% após endarterectomia carotídea.

Percentual de Registros com incidência abaixo de 3% de acidente vascular cerebral em 30 dias após intervenção carotídea assintomática. CAS: Angioplastia Carotídea e Stenting; CEA: Endarterectomia Carotídea. Paraskevas KI, Kalmykov EL, Naylor AR. Stroke/Death Rates Following Carotid Artery Stenting and Carotid Endarterectomy in Contemporary Administrative Dataset Registries: ASystematic Review. Eur J Vasc Endovasc Surg. 2015;51(1):3-12.

Percentual de Registros com incidência abaixo de 6% de acidente vascular cerebral em 30 dias após intervenção carotídea sintomática. CAS: Angioplastia carotídea e stenting; CEA: endarterectomia carotídea. Paraskevas KI, Kalmykov EL, Naylor AR. Stroke/Death Rates Following Carotid Artery Stenting and Carotid Endarterectomy in Contemporary Administrative Dataset Registries: ASystematic Review. Eur J Vasc Endovasc Surg. 2015;51(1):3-12.

Stent carotídeo: o efeito da idade e do operador

A população idosa geralmente apresenta tortuosidade vascular e uma grande carga de aterosclerose, características que aumentam as complicações após procedimentos de angioplastia. A idade tem sido associada a acidente vascular cerebral periprocedimental e morte após a CAS, a mesma descoberta não foi relatada após a CEA.33 Uma meta-análise de Cochrane de 16 ensaios clínicos randomizados34 e uma sub-análise do ensaio CREST35 descreveu uma associação de idade ≥ 70 anos e risco periprocedimental aumentado após a CAS. Uma meta-análise de quatro ensaios randomizados (EVA-3S, SPACE, ICSS e CREST) descobriu que o risco periprocedimental de acidente vascular cerebral ou morte após o CAS era de 3% para pacientes abaixo de 60 anos e 12% para aqueles acima de 70 anos, enquanto o risco de acidente vascular cerebral periprocedimental e morte permaneceu estável em 5% ao longo de todo o espectro etário no grupo da CEA.33

A possibilidade de que o operador seja um fator crucial para os bons resultados na intervenção percutânea carotídea foi levada em consideração no projeto dos protocolos de ensaios clínicos envolvendo CAS. Na tentativa de padronizar o grupo de operadores, o estudo EVA-3S8 incluiu apenas intervencionistas com, no mínimo, 12 angioplastias carotídeas realizadas anteriormente. O estudo SPACE9 exigiu um mínimo de vinte e cinco procedimentos anteriores. Apesar de a maioria dos estudos relatar o volume total de procedimentos realizados pelo operador, os poucos que foram especificamente direcionados para este argumento não foram capazes de mostrar uma associação entre uma experiência anterior do operador e taxas mais baixas de complicações.36-38

A análise combinada de três grandes ensaios randomizados (EVA-3S, SPACE e ICSS), publicado em 2012,39 mostrou diferenças grandes na incidência de morte ou acidente vascular cerebral quando os operadores foram estratificados por volume anual de procedimentos. Procedimentos realizados por operadores com, pelo menos, seis angioplastias carotídeas por ano tiveram uma incidência de acidente vascular cerebral e morte em 30 dias de 5,1%, enquanto procedimentos realizados por aqueles com três, ou menos, mostrou uma incidência de 10,1%. É importante observar que todos os operadores incluídos na análise já havia realizado um número mínimo de procedimentos, quer dizer, já haviam ultrapassado a curva de aprendizado. Ao contrário do volume anual, o volume total de procedimentos carotídeos realizados durante a vida do operador não teve associação com o aumento de complicações, como acidente vascular cerebral e morte, em conformidade com outros estudos publicados anteriormente.40

Revascularização de pacientes sintomáticos - um benefício sensível ao tempo

Os resultados dos principais estudos com pacientes sintomáticos demonstram que o maior benefício da intervenção ocorre nas primeiras semanas após o evento-índice.41-43 Depois dos primeiros 14 dias, há uma queda rápida no benefício da intervenção, e mais de 70% do efeito protetivo é visto dentro dos primeiros 30 dias; após dois anos, um paciente sintomático apresenta o mesmo nível de risco que um paciente assintomático.41-43

Entretanto, essa recomendação tem sido mal implementada, com menos de 20% se submetendo a revascularização dentro das duas semanas do início do acidente vascular cerebral ou do TIA.44 Uma iniciativa nacional dinamarquesa conseguiu aumentar o percentual da CEA dentro da janela de tempo recomendada, de 13% em 2007 para 47% em 2010.45 A prova da segurança do procedimento precoce é mais robusta para CEA do que para CAS, o que apresenta resultados conflitantes em diferentes estudos.46-48

A prevenção secundária para pacientes com grandes áreas isquêmicas apresenta um questionável benefício clínico a longo prazo. Ainda, devido ao alto risco de hemorragia intracraniana quando se realiza a intervenção carotídea nas primeiras semanas após um grande acidente vascular cerebral, a intervenção é somente indicada em casos de acidente isquêmico temporário ou de acidentes vasculares cerebrais pequenos.49

Paciente com lesão carotídea assintomática severa

O estudo ACAS, publicado em 1995 mostrou que o risco ajustado de acidente vascular cerebral e morte associado à intervenção era de 2,3% com a endarterectomia, evitando 59 acidentes vasculares cerebrais em cinco anos para cada 1.000 procedimentos realizados. Apesar do risco cirúrgico bastante baixo, quando comparado ao observado fora de um ECR e mesmo com as antigas práticas farmacológicas, 94% dos CEA eram desnecessários. Com um ajuste do risco periprocedimental para 0%, oitenta e dois acidentes vasculares cerebrais poderiam ser evitados a cada mil endarterectomias, mas ainda assim 92% dos pacientes estariam sendo submetidos a um procedimento sem benefícios. O mesmo princípio pode ser aplicado ao resultado de 10 anos do ACST que mostrou que, com uma redução do risco periprocedimental para 0%, 74 acidentes vasculares cerebrais poderiam ser evitados a cada mil endarterectomias, o que significa que 93% dos procedimentos teriam sido desnecessários.17

Os grandes ensaios clínicos realizados atualmente têm sido limitados à comparação entre angioplastia carotídea e cirurgia. A falta de um grupo de terapia clínica no estudo ACT I, publicado em 2016, foi fortemente criticado.50 As novas edições dos estudos SPACE, SPACE-2 (ISRCTN78592017), e CREST, CREST-2 (NCT02089217), planejaram a inclusão de um terceiro grupo em terapia clínica, mas o estudo SPACE-2 foi suspenso devido a uma taxa muito pequena de inclusões. Atualmente, o ensaio CREST-2 inclui mais de 780 dos 2.480 pacientes referidos.

As diretrizes atuais da Sociedade Europeia de Cardiologia (European Society of Cardiology) para pacientes assintomáticos com lesões severas e um risco cirúrgico moderado recomendam endarterectomia (Classe IIa) na presença de características clínicas e/ou resultados de imagem que sugiram um risco aumentado de acidente vascular cerebral ipsilateral tardio. Deve ser avaliada a angioplastia (Classe IIa) para pacientes com alto risco para endarterectomia, desde que as taxas de morte ou acidente vascular cerebral periprocedimental sejam < 3% e a expectativa de vida dos pacientes seja maior do que cinco anos, para qualquer indivíduo nos grupos.31

A população com estenose carotídea assintomática grave não é homogênea. Algumas linhas de pesquisa tentam identificar pacientes com risco mais alto através de estudos de imagem mais detalhados para localizar marcadores placas vulneráveis e microembolização.51,52 Isso permitiria uma revascularização carotídea mais rentável em pacientes atualmente classificados como assintomáticos.

 Discussão

A presente análise se concentra na prevenção primária e secundária do acidente vascular cerebral isquêmico através de revascularização carotídea, o que poderia impactar 14% de todos os acidentes vasculares cerebrais.16

Os primeiros estudos sobre esse assunto foram publicados no início da década de 1990. Desde os anos 2000, os estudos têm focado na comparação entre angioplastia e endarterectomia carotídea, sem a inclusão de um grupo de terapia clínica para comparação. Neste período, tem havido melhorias significativas no tratamento clínico e uma melhora no controle dos fatores de risco. O uso de ácido acetilsalicílico para prevenção cardiovascular já era rotina décadas antes de ser observado um declínio nas taxas de eventos cardiovasculares, o que sugere que outras classes de drogas são responsáveis por essa mudança. Nas últimas décadas, diversos estudos têm mostrado o impacto das estatinas sobre os resultados cardiovasculares, com uma redução na incidência de até 50%.26

Os dados analisados no presente estudo mostram que, para um benefício líquido do procedimento, a intervenção carotídea deve ser realizada apenas em casos de risco periprocedimental inferior a 6% em pacientes sintomáticos ou de 3% em pacientes assintomáticos. Uma análise sistemática publicada em 2015 mostrou que revascularização carotídea é mais eficiente em pacientes sintomáticos, mas é associada a uma maior incidência de morte e acidente vascular cerebral. Além disso, os resultados não mostraram uma tendência a resultados melhores após a realização de stent carotídeo entre 2008 e 2015, o que sugere que essa modalidade de intervenção, apesar de menos invasiva, possui maiores taxas de complicações mesmo em pacientes com alto risco cirúrgico.13

Dados relativos ao efeito do operador na CAS mostram que a experiência anterior é importante e pode influenciar na taxa de complicações sérias. Uma diferença de quase 100% na incidência dos resultados de 30 dias de acidente vascular cerebral e morte entre diferentes grupos de operadores já foi observado em ensaios clínicos.40 O volume anual de procedimentos carotídeos realizados pelo operador é o fator que melhor se correlacionou a taxas menores de complicações.40

A indicação para intervenção carotídea em pacientes sintomáticos mostrou um benefício maior nas primeiras semanas do evento. Nesse contexto, a diretriz comum da American Heart Association e da American Stroke Association para prevenção do acidente vascular cerebral em pacientes sintomáticos, publicada em 2014, recomenda como classe IIa que revascularização carotídea ocorra dentro de duas semanas do evento-índice, caso não haja nenhuma complicação que contraindique o procedimento.30 A diretriz de 2017 da Sociedade Europeia de Cardiologia (ESC Guidelines on the Diagnosis and Treatment of Peripheral Arterial Diseases, em colaboração com a Sociedade Europeia para Cirurgia Vascular), manteve essa recomendação.31

A indicação de intervenção carotídea ainda é questionável no caso de pacientes assintomáticos, uma vez que os estudos publicados até então mostram uma alta taxa de procedimentos desnecessários.53 Atualmente, alguns estudos tentam identificar pacientes assintomáticos com riscos mais altos que poderiam vir a se submeter a um procedimento de revascularização carotídea mais rentável.

 Conclusão

A lesão grave da artéria carótida extracraniana é responsável por 14% de todos os acidentes vasculares cerebrais. A revascularização carotídea vem sendo realizada há mais de 50 anos, e diversos estudos tem provado que a intervenção pode evitar esse desfecho, mas com risco não-negligenciável de complicações graves. Mais recentemente, os procedimentos de angioplastia carotídea tem ampliado a escala de opções invasivas, mas não foi observada a redução estimada do risco periprocedimental. Além disso, a incidência aumentada de aterosclerose resultou em uma grande heterogeneidade de pacientes que são candidatos possíveis a endarterectomia ou a angioplastia, e a evolução de terapia farmacológica mudou a proporção do risco-benefício da intervenção em diversos casos de doença aterosclerótica. Com relação aos pacientes tratados com a melhor terapia médica atual, a intervenção carotídea apenas deveria ser realizada quando houver um risco periprocedimental documentado de menos de 6%, em pacientes sintomáticos. Apesar de diretrizes principais endossarem a intervenção em pacientes assintomáticos desde que o risco periprocedimental seja inferior a 3%, a magnitude restrita da prevenção absoluta de acidentes vasculares cerebrais coloca a intervenção carotídea como um procedimento questionável em uma população assintomática não-selecionada.

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