Arq Bras Cardiol abc Arquivos Brasileiros de Cardiologia Arq. Bras. Cardiol. 0066-782X 1678-4170 Sociedade Brasileira de Cardiologia - SBC zh5p4SGyX74DgPJGVwhFzJc S0066-782X2016000300194 S0066-782X2016005006101 10.5935/abc.20160024 Original Articles The Relationship between GRACE Score and Epicardial Fat Thickness in non-STEMI Patients Gul Ilker 1 Zungur Mustafa 1 Aykan Ahmet Cagri 2 Gokdeniz Teyyar 3 Kalaycioğlu Ezgi 2 Turan Turhan 2 Hatem Engin 4 Boyaci Faruk 5 Şifa University Faculty of Medicine Department of Cardiology Izmir Turkey Şifa University Faculty of Medicine - Department of Cardiology, Izmir - Turquia Sifa University Ahi Evren Thoracic and Cardiovascular Surgery Training and Research Hospital Department of Cardiology Trabzon Turquia Ahi Evren Thoracic and Cardiovascular Surgery Training and Research Hospital - Department of Cardiology, Trabzon - Turquia Kafkas University Faculty of Medicine Department of Cardiology Kars Turkey Kafkas University Faculty of Medicine - Department of Cardiology, Kars - Turquia Kafkas University Erzurum Region Education and Research Hospital Erzurum Turquia Erzurum Region Education and Research Hospital, Erzurum - Turquia Samsun Education and Research Hospital Samsun Turquia Samsun Education and Research Hospital, Samsun - Turquia Mailing Address: Ilker Gul, Department of Cardiology, Sifa University Faculty of Medicine Bornova Hospital, Postal Code 35040, İzmir - Turkey. E-mail: drilkergul46@gmail.com

Author contributions

Conception and design of the research: Gul I, Zungur M, Aykan AC, Gokdeniz T, Kalaycioğlu E, Turan T, Boyaci F; Acquisition of data: Gul I, Zungur M, Aykan AC, Turan T, Hatem E; Analysis and interpretation of the data: Gul I, Zungur M, Aykan AC, Kalaycioğlu E, Hatem E, Boyaci F; Statistical analysis: Gul I, Zungur M, Aykan AC, Gokdeniz T, Kalaycioğlu E, Turan T, Hatem E; Writing of the manuscript: Gul I; Critical revision of the manuscript for intellectual content: Gul I, Zungur M, Aykan AC, Gokdeniz T.

Potential Conflict of Interest

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

 16 02 2016 3 2016 106 3 194 200 20 06 2015 10 11 2015 10 11 2015 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 Background:

GRACE risk score (GS) is a scoring system which has a prognostic significance in patients with non-ST segment elevation myocardial infarction (non-STEMI).

 Objective:

The present study aimed to determine whether end-systolic or end-diastolic epicardial fat thickness (EFT) is more closely associated with high-risk non-STEMI patients according to the GS.

 Methods:

We evaluated 207 patients who had non-STEMI beginning from October 2012 to February 2013, and 162 of them were included in the study (115 males, mean age: 66.6 ± 12.8 years). End-systolic and end-diastolic EFTs were measured with echocardiographic methods. Patients with high in-hospital GS were categorized as the H-GS group (in hospital GS > 140), while other patients were categorized as the low-to-moderate risk group (LM-GS).

 Results:

Systolic and diastolic blood pressures of H-GS patients were lower than those of LM-GS patients, and the average heart rate was higher in this group. End-systolic EFT and end-diastolic EFT were significantly higher in the H-GS group. The echocardiographic assessment of right and left ventricles showed significantly decreased ejection fraction in both ventricles in the H-GS group. The highest correlation was found between GS and end-diastolic EFT (r = 0.438).

 Conclusion:

End-systolic and end-diastolic EFTs were found to be increased in the H-GS group. However, end-diastolic EFT and GS had better correlation than end-systolic EFT and GS.

 Keywords: Acute Coronary Syndrome Adipose Tissue Myocardial Infarction Echocardiography Pericardium Introduction

Various scoring systems have been developed for prognostic assessment of patients hospitalized with acute coronary syndromes (ACS). American Heart Association (AHA) and European Society of Cardiology (ESC) guidelines emphasize the prognostic importance of GRACE risk score (GS), and recommend it for routine use. GS can be calculated for the in-hospital period and for the six months following discharge from the hospital. In-hospital GS > 140 is considered as increased risk in terms of mortality rates. Early intervention and revascularization therapies are recommended for these patients.1,2

Visceral adipose tissue is known to have endocrine and metabolic activity functions. Epicardial fat (adipose) tissue is a type of visceral adipose tissue that extends along with the coronary arteries. The importance of epicardial fat thickness (EFT) has been shown by growing amount of supportive data in recent years. Increased EFT is associated with hypertension, insulin resistance and inflammatory processes such as diabetes mellitus and metabolic syndrome.3-5 As a result of the studies investigating the relationship between EFT and coronary artery disease (CAD), EFT was associated with severity and burden of CAD.6-11

EFT can be measured by means of magnetic resonance imaging (MRI) and multi-detector computed tomography (CT). However, these tests are quite expensive and not for routine use. Echocardiography is quite inexpensive, readily available and easy to perform compared to CT and MRI. For these reasons, the majority of previous studies have calculated EFT using echocardiographic methods. There is no consensus on during which phase of the cardiac cycle EFT should be measured. Although some studies in the literature suggest using end-systolic EFT measurements,7,11,12 a greater number of studies recommend end-diastolic EFT measurements.5-8

The present study aimed to determine whether end-systolic or end-diastolic EFT is more closely associated with high-risk non-ST segment elevation myocardial infarction (non-STEMI) patients according to the GS.

 Methods

This prospective observational cohort study was carried out between October 2012 and February 2013. Patients who had non-STEMI for the first time were included in the study. Patients with chronic lung disease, chronic liver disease, inflammatory rheumatic disease, muscle disease, heart failure, chronic renal failure (creatinine > 2.5 mg/dL), myocarditis, and cardiomyopathic disease were excluded from the study.

Non-STEMI was diagnosed in the presence of an accelerating pattern of or prolonged angina or recurrent episodes of angina either at rest or during minimal exertion within the last 48-72 hours and levels of troponin or creatine kinase-MB (CK-MB) above the upper limit of normal range. Biochemical parameters were evaluated in blood samples collected during hospitalization. Peak cTnI and CK-MB levels were identified during the cardiac enzyme follow-up.

The GS was calculated by means of a computer program (www.outcomes-umassmed.org/grace/acs_risk). Age, systolic blood pressure, serum creatinine level, and Killip class were determined for GS. Cardiac arrest on admission, ST-segment changes, the method of revascularization and data about the increase in cardiac enzymes were entered into the computer program as appropriate. After GS values were calculated, the patients were divided into groups as recommended by the AHA and ESC guidelines on non-STEMI.1,2

Patients with low-to-moderate in-hospital GS (< 140) were categorized as the low-to-moderate GRACE score (LM-GS) group (n = 70) while the patients with high in-hospital GS (> 140) were categorized as the high GRACE score (H-GS) group (n = 92).

Baseline clinical [heart rate, blood pressure, electrocardiography, laboratory biochemical parameters, angiography], echocardiographic and demographic [age, gender, height, weight] variables of the patients were recorded. The predictor (grouping) variable was the GS, and the primary outcome variable was EFT.

Echocardiography

Echocardiographic analysis was performed in left lateral decubitus position according to the American Society of Echocardiography guidelines, within the first 24 hours in intensive care unit using the Vivid S5 cardiovascular ultrasound system (General Electric Vingmed Ultrasound, Horten, Norway). Epicardial fat was defined as an echo-free space between the outer wall of the myocardium and the visceral layer of the pericardium. The largest diameter of epicardial fat located on the right ventricular (RV) free wall was determined. EFT was measured in the parasternal long axis view at end-systole and end-diastole in three cardiac cycles. The average of three cardiac cycles was used for statistical analysis.

Left ventricular ejection fraction (LVEF) was determined using the Modified Simpson method. For a better evaluation of the RV functions, tricuspid annular plane systolic excursion (TAPSE) amount was calculated from the lateral tricuspid annulus.13 The right ventricular ejection fraction (RVEF) was calculated with 3D echocardiography using the disk summation method. The myocardial performance index, also known as Tei index, is a global estimate of both RV functions. Tei index is a Doppler-derived time interval index that combines both systolic and diastolic cardiac performance. The Tei index is easily derived using conventional pulsed Doppler echocardiography, as previously described by Tei et al.14

The present study has been designed and conducted in accordance with the Declaration of Helsinki, and the protocol has been approved by the Ethics Committee.

 Variability analysis

Intra- and inter-observer variability were assessed for the echocardiographic data obtained from a subgroup of 40 subjects. One day later, the first operator repeated the analysis to assess intra-observer variability. To assess inter-observer variability, the second operator who was blinded to the previous measurements analyzed each parameter two days later. Agreement analysis for inter- and intra-observer variability of EFT measurements revealed a high level of agreement with a mean difference of 0.26 (95% limit of agreement: -0.5 to 0.93) and an intraclass correlation coefficient of 0.918 (95% CI 0.830-0.960).

 Statistical analysis

Categorical data are presented as frequencies (percentages). Continuous variables are presented as mean ± SD. Kolmogorov-Smirnov test was used to assess whether patients' data fit normal distribution. As the data exhibited normal distribution, the independent-samples t-test was used for statistical analysis. Chi-square analysis was performed for categorical variables. Intraclass correlation coefficients and Bland-Altman analysis were used for echocardiographic measurements to assess intra- and inter-observer reproducibility, respectively. Pearson's test was used to analyze the correlation between GS and EFT. Receiver operating characteristic (ROC) analysis was performed to determine whether EFT could predict high-risk groups based on GS scores. A two-tailed p < 0.05 was considered statistically significant.

 Results Baseline demographics and characteristics

We evaluated 207 patients admitted to our center with non-STEMI, and 45 of them were excluded from the study (chronic lung disease, 22 patients; chronic liver disease, 2 patients; previous heart failure, 10 patients; chronic renal failure, 8 patients; myocarditis, 2 patients; and cardiomyopathic disease, 1 patient). Totally 162 patients were included in the study and 115 of them were male, and the average age was 63.9 ± 12.8 years. According to in-hospital GS, 70 patients were categorized as the LM-GS group, and 92 patients were categorized as the H-GS group. The mean age was higher in the H-GS group (73.7 ± 10.5 vs. 57.2 ± 9.1 years, p < 0.001). Mean systolic blood pressure (147.3 ± 27.7 vs. 130.3 ± 31.1 mmHg, p < 0.001) and mean diastolic blood pressure (85.5 ± 16.1 vs. 78.1 ± 19.5 mmHg, p = 0.010) values were higher in the LM-GS group. There was no difference between the groups in terms of body mass index, smoking, and the number of patients with hypertension, and diabetes mellitus. Mortality rate [3 (4.3%) vs. 13 (14.1%), p = 0.037], length of stay in intensive care unit [3.3 ± 1.2 days vs. 4.3 ± 2.9 days, p = 0.019] and total length of hospital stay [5.6 ± 2.5 days vs. 6.9 ± 3.8 days, p = 0.020] were significantly higher in the H-GS group compared to the LM-GS group (Table 1).

General characteristics of patients with non-ST-elevatlon myocardial Infarction according to the in-hospital GRACE score
Low-to-moderate risk group (n = 70) High risk group (n = 92) p value
Age, years 57.2 ± 9.1 73.7 ± 10.5 p < 0.001
Gender, male/female 56/14 59/33 p = 0.027
Systolic Blood Pressure, mmHg 147.3 ± 27.7 130.3 ± 31.1 p < 0.001
Diastolic Blood Pressure, mmHg 85.5 ± 16.1 78.1 ± 19.5 p = 0.010
Body Mass Index, kg/m2 28.5 ± 4.4 26.7 ± 3.7 p = 0.060
Smoking, n (%) 35 (50%) 50 (54.1%) p = 0.583
Hypertension, n (%) 40 (57.1%) 44 (47.8%) p = 0.299
Diabetes mellitus, n (%) 21 (30.0%) 33 (35.9%) p = 0.376
Blood Glucose on admission, mg/dL 139.6 ± 60.3 146.5 ± 70.3 p = 0.515
Total Cholesterol, mg/dL 185.7 ± 44.9 204.2 ± 55.9 p = 0.022
LDL Cholesterol, mg/dL 133.1 ± 37.9 148.5 ± 43.9 p = 0.019
HDL Cholesterol, mg/dL 40.9 ± 15.9 39.9 ± 9.8 p = 0.627
Triglycerides, mg/dL 124.8 ± 71.4 131.3 ± 96.8 p = 0.641
C-Reactive Protein, mg/dL 1.63 ± 3.4 2.68 ± 4.38 p = 0.013
Creatinine, mg/dL 0.84 ± 0.2 1.18 ± 0.57 p < 0.001
Troponin-I, ng/mL 31.6 ± 30.0 31.1 ± 28.1 p = 0.951
LV Ejection Fraction, % 47.8 ± 10.2 43.3 ± 10.5 p = 0.008
Interventricular septum, mm 10.1 ± 1.2 10.1 ± 1.36 p = 0.726
Posterior Wall, mm 9.8 ± 1.12 9.9 ± 1.26 p = 0.761
LV Mass, g 181.5 ± 44.2 198.7 ± 49.3 p = 0.019
LV Mass Index, g/m2 94.3 ± 22.4 109.4 ± 28.4 p = 0.002
Epicardial fat thickness (systole), cm 0.72 ± 0.17 0.81 ± 0.12 p < 0.001
Epicardial fat thickness (diastole), cm 0.46 ± 0.13 0.54 ± 0.10 p < 0.001
SPAP, mmHg 25.1 ± 7.5 30.7 ± 8.7 p < 0.001
TAPSE, mm 20.9 ± 4.1 19.4 ± 3.6 p = 0.017
RV Ejection Fraction, % 53.1 ± 5.3 50.1 ± 5.4 p = 0.001
Tei Index 0.35 ± 0.09 0.44 ± 0.11 p < 0.001
SYNTAX score 20.6 ± 10.1 21.2 ± 9.9 p = 0.625
LAD lesion, n (%) 29 (41.4%) 35 (38.0%) p = 0.744
Cx lesion, n (%) 17 (24.3%) 16 (17.4%) p = 0.280
RCA lesion, n (%) 24 (34.3%) 41 (44.6%) p = 0.149
Mortality, n (%) 3 (4.3%) 13 (14.1%) p = 0.037
Duration in intensive care unit, days 3.3 ± 1.2 4.3 ± 2.9 p = 0.019
Total length of hospital stay, days 5.6 ± 2.5 6.9 ± 3.8 p = 0.020

Data are presented as mean±SD or number (percentage)

*Chi-square and independent sample t-test

LV: Left ventricular; RV: right ventricular; Cx: circumflex artery; HDL: high density lipoprotein; LAD: left anterior descending artery; LDL: low-density lipoprotein; RCA: right coronary artery; SPAP: systolic pulmonary artery pressure; TAPSE: tricuspid annular plane systolic excursion.

 Laboratory findings

Evaluation of the laboratory data revealed no difference between the average values of postprandial blood glucose, HDL-cholesterol, triglycerides, and cTn-I levels. The mean values of total cholesterol (204.2 ± 55.9 vs. 185.7 ± 44.9 mg/dL, p = 0.022), LDL-cholesterol (148.5±43.9 vs. 133.1 ± 37.9 mg/dL, p = 0.019), C-reactive protein (2.68 ± 4.38 vs. 1.63 ± 3.4 mg/L, p = 0.013) and creatinine (1.18 ± 0.57 vs. 0.84 ± 0.20 mg/dL, p < 0.001) were higher in the H-GS group compared to the LM-GS group (Table 1).

Echocardiography and coronary angiography

There was no difference between the groups regarding interventricular septum and posterior wall thickness. EF was lower in the H-GS group (43.3% ± 10.5 vs. 47.8% ± 10.2, p = 0.008). End-systolic EFT (0.81 ± 0.12 vs. 0.72 ± 0.17 cm, p < 0.001), end-diastolic EFT (0.54 ± 0.10 vs. 0.46 ± 0.13 cm, p < 0.001) and systolic pulmonary artery pressure (SPAP) (30.7 ± 8.7 vs. 25.1 ± 7.5 mmHg, p < 0.001) were higher in the H-GS group. RVEF, one of the indicators of RV systolic function (50.1% ± 5.4 vs. 53.1% ± 5.3, p = 0.001) and TAPSE (19.4 ± 3.6 vs. 20.9 ± 4.1, p = 0.017) were lower in the H-GS group than in the LM-GS group (Table 1). Tei index was significantly higher in the H-GS group (0.48 ± 0.09 vs. 0.39 ± 0.08, p < 0.001).

Evaluation of the patients' angiograms showed no significant difference between left anterior descending (LAD), circumflex (Cx) and right coronary artery (RCA) involvements (Table 1).

 Correlation and ROC analysis

Based on in-hospital GS, the ROC analysis was performed to calculate the EFT for prediction of patients with high-risk. The end-systolic EFT cut-off value which predicts the H-GS group was calculated as 0.765 cm (AUC: 0.699; 95% CI: 0.613-0.785; sensitivity, 67%; specificity, 64%), and the end-diastolic EFT cut-off value was found to be 0.468 cm for the H-GS group (AUC: 0.709; 95% CI: 0.621-0.797; sensitivity, 68%; specificity, 72%) (Table 2, Figure 1).

According to in-hospital GRACE scores (GS), the receiver operating characteristic (ROC) analysis was performed to calculate the epicardial fat thickness (EFT) for the prediction of patients at high risk
Cut-off (cm) Sensitivity Specificity AUC 95% Confidence Interval
EFT end-systole / GS 0.765 67% 64% 0.699 0.613-0.785
EFT end-diastole / GS 0.468 68% 72% 0.709 0.621-0.797

Receiver operating characteristic (ROC) analysis

AUC: area under the curve.

Receiver operating characteristic (ROC) curve.The end-systolic epicardial fat thickness cut-off value which predicts the H-GS group was calculated as 0.765 cm (AUC: 0.699; 95% CI: 0.613-0.785; sensitivity: 67%; specificity: 64%). End-diastolic epicardial fat thickness cut-off value was found to be 0.468 cm for the H-GS group (AUC: 0.709; 95% CI: 0.621-0.797; sensitivity: 68%; specificity: 72%). (AUC: Area Under the Curve; CI: Confidence Interval; H-GS: High GRACE score).

The correlation coefficient (r) of in-hospital GS and end-systolic EFT was found as 0.387, while the correlation coefficient (r) of in-hospital GS and end-diastolic EFT was found as 0.438 (Table 3).

Correlation table for the in-hospital GRACE score (GS), SYNTAX score and epicardial fat thickness (EFT) measurements
Correlation coefficient (r) p value
End-systolic EFT - GS r = 0.387 < 0.001
End-diastolic EFT - GS r = 0.438 < 0.001
End-systolic EFT - SYNTAX score r = 0.285 0.009
End-diastolic EFT - SYNTAX score r = 0.292 0.002

Pearson’s correlation analysis

 Discussion

In this study, we aimed to show the relationship between the GS and EFT in patients admitted to our center with a diagnosis of non-STEMI. Our study demonstrated that EFT is associated with increased GS, and statistical analysis suggests that it would be more convenient to measure EFT at the end of diastole.

GRACE scoring system was initially used for the purpose of following a prognostic assessment of patients with ACS after the multinational Global Registry of Acute Coronary Events (GRACE) study.15,16 Detection of a high GS calculated with the help of variables is associated with poor prognosis. Currently, the ACS guidelines recommend its use for risk evaluation. The AHA and ESC ACS diagnosis and treatment guidelines provide suggestions on how to interpret GS. According to these recommendations, in-hospital GS > 140 is an indicator of high morbidity and mortality. These guidelines recommend early revascularization for patients at high risk.1,2 In our study, a higher mortality rate was found (p = 0.001) in the H-GS group with GS > 140. Apart from mortality rates, echocardiographic parameters decreased in the H-GS group. The LVEF values of the H-GS group were lower than those of the LM-GS group. The RVEF and TAPSE, which are markers of RV systolic functions, were decreased in the H-GS group. The Tei index and SPAP were increased in the H-GS group.

Epicardial fat is a type of visceral adipose tissue that extends along coronary arteries in atrioventricular and interventricular grooves. Myocardium and epicardial fat tissue are in direct contact, and the blood supply for these tissues is provided by the same coronary system.17 Therefore, acting as an endocrine organ, epicardial fat tissue can directly and indirectly affect coronary arteries and cardiac structures. Epicardial fat tissue can produce several cytokines that stimulate angiogenesis, inflammation, oxidative stress and atherosclerosis. A number of recent clinical studies have been conducted to investigate the relationship between EFT and cardiovascular diseases. As a result of these studies, increased EFT has been associated with an increased risk of cardiovascular disease.5-7,11,18-22 EFT is increased in patients with inflammation, advanced age, obesity, hypercholesterolemia, hypertension, atrial fibrillation, diabetes mellitus and metabolic syndrome.3,4,10,23-27 In our study, there was no significant difference between the groups in terms of blood glucose and body mass index. The number of patients diagnosed with metabolic syndrome, diabetes and hypertension was similar between groups (Table 1).

There are several recommendations on how to measure EFT. The RV free wall is preferred as the measurement site, and measurements for the calculation of EFT are generally performed at the end of diastole.5,8 However, some publications suggest that EFT can also be measured at the end of systole.(7,11,12 )It is recommended that EFT should be measured at the end of systole during the cardiac cycle as it is compressed during diastole. In the present study, average EFT values were obtained by employing at least three different measurements for end of systole and end of diastole, and the average EFT values were higher in the H-GS group compared to the LM-GS group (p < 0.001) (Table 1). A correlation was observed between in-hospital GS and EFT (in-hospital GS and end-systolic EFT, r = 0.387; end-diastolic, r = 0.438). Evaluation of ROC analyses demonstrated that end-diastolic EFT provided a better prediction of high GS compared to end-systolic EFT (Table 2, Figure 1).

The main limitation of the present study is the relatively small sample size. Secondly, echocardiography is less accurate than other radiological techniques for evaluating epicardial adipose tissue, although a good correlation with MRI has been reported. Moreover, a moderate correlation has been reported with the epicardial fat volume assessed with cardiovascular MRI. Despite the low level of accuracy, echocardiographic measurement of EFT offers greater feasibility compared to MRI.

 Conclusions

Previous studies have shown increased EFT in various conditions and pathologies that may impair cardiac functions. In our study mortality and morbidity rates were increased in H-GS group. The GS showed a positive correlation with end-systolic EFT and end-diastolic EFT. Statistical evaluations demonstrated a better correlation between GS and end-diastolic EFT rather than end-systolic EFT.

In conclusion, calculating the end-diastolic EFT may provide useful information in patients with high GS during the echocardiographic evaluation of non-STEMI.

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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Granger CB Goldberg RJ Dabbous OH Pieper KS Eagle KA Cannon CP Global Registry of Acute Coronary Events Investigators Predictors of hospital mortality in the global registry of acute coronary events Arch Intern Med 2003 163 19 2345 2353 16 Fox KA, Dabbous OH, Goldberg RJ, Pieper KS, Eagle KA, Van de Werf F, et al. Prediction of risk of death and myocardial infarction in the six months after presentation with acute coronary syndrome: prospective multinational observational study (GRACE). BMJ. 2006;333(7578):1091. Fox KA Dabbous OH Goldberg RJ Pieper KS Eagle KA Van de Werf F Prediction of risk of death and myocardial infarction in the six months after presentation with acute coronary syndrome: prospective multinational observational study (GRACE) BMJ 2006 333 7578 1091 1091 17 Iacobellis G, Willens HJ. Echocardiographic epicardial fat: a review of research and clinical applications. J Am Soc Echocardiogr. 2009;22(12):1311-9. Iacobellis G Willens HJ Echocardiographic epicardial fat: a review of research and clinical applications J Am Soc Echocardiogr 2009 22 12 1311 1319 18 Sacks HS, Fain JN, Cheema P, Bahouth SW, Garrett E, Wolf RY, et al. Depot-specific overexpression of proinflammatory, redox, endothelial cell and angiogenic genes in epicardial fat adjacent to severe stable coronary atherosclerosis. Metab Syndr Relat Disord. 2011;9(6):433-9 Sacks HS Fain JN Cheema P Bahouth SW Garrett E Wolf RY Depot-specific overexpression of proinflammatory, redox, endothelial cell and angiogenic genes in epicardial fat adjacent to severe stable coronary atherosclerosis Metab Syndr Relat Disord 2011 9 6 433 439 19 Spiroglou SG, Kostopoulos CG, Varakis JN, Papadaki HH, et al. Adipokines in periaortic and epicardial adipose tissue: differential expression and relation to atherosclerosis. J Atheroscler Thromb. 2010;17(2):115-30. Spiroglou SG Kostopoulos CG Varakis JN Papadaki HH Adipokines in periaortic and epicardial adipose tissue: differential expression and relation to atherosclerosis J Atheroscler Thromb 2010 17 2 115 130 20 Nabati M, Saffar N, Yazdani J, Parsaee MS. Relationship between epicardial fat measured by echocardiography and coronary atherosclerosis: a single-blind historical cohort study. Echocardiography. 2013;30(5):505-11. Nabati M Saffar N Yazdani J Parsaee MS Relationship between epicardial fat measured by echocardiography and coronary atherosclerosis: a single-blind historical cohort study Echocardiography 2013 30 5 505 511 21 Tanindi A, Kocaman SA, Erkan AF, Ugurlu M, Alhan A, Töre HF. Epicardial adipose tissue thickness is associated with myocardial infarction and impaired coronary perfusion. Anatol J Cardiol. 2015;15(3):224-31. Tanindi A Kocaman SA Erkan AF Ugurlu M Alhan A Töre HF Epicardial adipose tissue thickness is associated with myocardial infarction and impaired coronary perfusion Anatol J Cardiol 2015 15 3 224 231 22 Pracon R, Kruk M, Kepka C, Pregowski J, Opolski MP, Dzielinska Z, et al. Epicardial adipose tissue radiodensity is independently related to coronary atherosclerosis. A multidetector computed tomography study. Circ J. 2011;75(2):391-7. Pracon R Kruk M Kepka C Pregowski J Opolski MP Dzielinska Z Epicardial adipose tissue radiodensity is independently related to coronary atherosclerosis. A multidetector computed tomography study Circ J 2011 75 2 391 397 23 Karadag B, Ozulu B, Ozturk FY, Oztekin E, Sener N, Altuntas Y, et al. Comparison of epicardial adipose tissue (EAT) thickness and anthropometric measurements in metabolic syndrome (MS) cases above and under the age of 65. Arch Gerontol Geriatr 2011;52(2):e79-84. Karadag B Ozulu B Ozturk FY Oztekin E Sener N Altuntas Y Comparison of epicardial adipose tissue (EAT) thickness and anthropometric measurements in metabolic syndrome (MS) cases above and under the age of 65 Arch Gerontol Geriatr 2011 52 2 e79 e84 24 de Vos AM, Prokop M, Roos CJ, Meijs MF, van der Schouw YT, Rutten A, et al. Peri-coronary epicardial adipose tissue is related to cardiovascular risk factors and coronary artery calcification in post-menopausal women. Eur Heart J. 2008;29(6):777-83. de Vos AM Prokop M Roos CJ Meijs MF van der Schouw YT Rutten A Peri-coronary epicardial adipose tissue is related to cardiovascular risk factors and coronary artery calcification in post-menopausal women Eur Heart J 2008 29 6 777 783 25 Erdogan T, Çetin M, Kocaman SA, Durakoglugil ME, Ergül E, Ugurlu Y, et al. Epicardial adipose tissue is independently associated with increased left ventricular mass in untreated hypertensive patients: an observational study. Anadolu Kardiyol Derg. 2013;13(4):320-7. Erdogan T Çetin M Kocaman SA Durakoglugil ME Ergül E Ugurlu Y Epicardial adipose tissue is independently associated with increased left ventricular mass in untreated hypertensive patients: an observational study Anadolu Kardiyol Derg 2013 13 4 320 327 26 Lin YK, Chen YJ, Chen SA. Potential atrial arrhythmogenicity of adipocytes: implications for the genesis of atrial fibrillation. Med Hypotheses. 2010;74(6):1026-9. Lin YK Chen YJ Chen SA Potential atrial arrhythmogenicity of adipocytes: implications for the genesis of atrial fibrillation Med Hypotheses 2010 74 6 1026 1029 27 Tok D, Özcan F, Kadife I, Turak O, Çagli K, Basar N, et al. Impaired coronary flow reserve evaluated by echocardiography is associated with increased aortic stiffness in patients with metabolic syndrome: an observational study. Anadolu Kardiyol Derg. 2013;13(3):227-34. Tok D Özcan F Kadife I Turak O Çagli K Basar N Impaired coronary flow reserve evaluated by echocardiography is associated with increased aortic stiffness in patients with metabolic syndrome: an observational study Anadolu Kardiyol Derg 2013 13 3 227 234 Artigos Originais Relação entre Escore GRACE e Espessura da Gordura Epicárdica em Pacientes com IMSSST Gul Ilker 1 Zungur Mustafa 1 Aykan Ahmet Cagri 2 Gokdeniz Teyyar 3 Kalaycioğlu Ezgi 2 Turan Turhan 2 Hatem Engin 4 Boyaci Faruk 5 Şifa University Faculty of Medicine - Department of Cardiology, Izmir - Turquia Ahi Evren Thoracic and Cardiovascular Surgery Training and Research Hospital - Department of Cardiology, Trabzon - Turquia Kafkas University Faculty of Medicine - Department of Cardiology, Kars - Turquia Erzurum Region Education and Research Hospital, Erzurum - Turquia Samsun Education and Research Hospital, Samsun - Turquia Correspondência para: Ilker Gul, Sifa University Faculty of Medicine Bornova Hospital, Postal Code 35040, İzmir - Turquia. E-mail: drilkergul46@gmail.com

Contribuição dos autores

Concepção e desenho da pesquisa: Zungur M, Gul I, Zungur M, Aykan AC, Gokdeniz T, Kalaycioğlu E, Turan T, Boyaci F; Obtenção de dados: Gul I, Zungur M, Aykan AC, Turan T, Hatem E; Análise e interpretação dos dados: Gul I, Zungur M, Aykan AC, Kalaycioğlu E, Hatem E, Boyaci F; Análise estatística: Gul I, Zungur M, Aykan AC, Gokdeniz T, Kalaycioğlu E, Turan T, Hatem E; Redação do manuscrito: Gul I; Revisão crítica do manuscrito quanto ao conteúdo intelectual importante: Gul I, Zungur M, Aykan AC, Gokdeniz T.

Potencial conflito de interesse

Declaro não haver conflito de interesses pertinentes.

 Resumo Fundamento:

O escore de risco GRACE (SG) é um sistema com significado prognóstico para pacientes com infarto do miocárdio sem supradesnivelamento do segmento ST (IMSSST).

 Objetivo:

Determinar se a espessura da gordura epicárdica (EGE) ao final da sístole ou da diástole é mais associada com pacientes de IMSSST de alto risco de acordo com o SG.

 Métodos:

Este estudo avaliou 207 pacientes com IMSSST desde outubro de 2012 a fevereiro de 2013, sendo 162 deles incluídos no estudo (115 homens, idade média: 66,6 ± 12,8 anos). Mediu-se a EGE ao final da sístole e da diástole com métodos ecocardiográficos. Pacientes com alto SG intra-hospitalar (SG > 140) foram classificados como grupo SG-A, enquanto os outros foram classificados como grupo de risco baixo-a-moderado (grupo SG-BM).

 Resultados:

As pressões arteriais sistólica e diastólica dos pacientes SG-A foram mais baixas do que as dos pacientes SG-BM, sendo a frequência cardíaca média mais alta nesse grupo. A EGE ao final da sístole e a EGE ao final da diástole foram significativamente mais altas no grupo SG-A. A avaliação ecocardiográfica dos ventrículos direito e esquerdo mostrou fração de ejeção significativamente reduzida em ambos os ventrículos no grupo SG-A. Observou-se maior correlação entre SG e EGE ao final da diástole (r = 0,438).

 Conclusão:

A EGE ao final da sístole e a EGE ao final da diástole mostraram-se aumentadas no grupo SG-A. Entretanto, a EGE ao final da diástole apresentou melhor correlação com o SG do que a EGE ao final da sístole.

 Palavras-chave: Síndrome Coronariana Aguda Tecido Adiposo Infarto do Miocárdio Ecocardiografia Pericárdio Introdução

Vários sistemas de escore foram desenvolvidos para avaliação prognóstica de pacientes hospitalizados com síndrome coronariana aguda (SCA). As diretrizes da American Heart Association (AHA) e da Sociedade Europeia de Cardiologia (ESC) enfatizam a importância prognóstica do escore de risco GRACE (SG), e recomendam seu uso rotineiro. O SG pode ser calculado para o período intra-hospitalar e para os seis meses que se seguem à alta. Um SG intra-hospitalar > 140 é considerado um risco aumentado em termos de mortalidade. Intervenção precoce e terapia de revascularização são recomendadas para esses pacientes.1,2

Sabe-se que o tecido adiposo visceral tem função endócrina e atividade metabólica. O tecido adiposo epicárdico é um tipo de tecido adiposo visceral que se estende ao longo das artérias coronárias. Recentemente, uma crescente quantidade de dados tem demonstrado a importância da espessura da gordura epicárdica (EGE). Seu aumento acha-se associado com hipertensão, resistência insulínica e processos inflamatórios, como diabetes mellitus e síndrome metabólica.3-5 Como resultado dos estudos investigando a relação entre EGE e doença arterial coronariana (DAC), a EGE associou-se com gravidade e carga da DAC.6-11

A EGE pode ser medida por ressonância nuclear magnética (RNM) e tomografia computadorizada com multidetectores (TC). Entretanto, esses exames são onerosos e não se prestam para uso rotineiro. A ecocardiografia tem preço reduzido e boa disponibilidade, sendo de fácil execução quando comparada à RNM e à TC. Por essas razões, a maioria dos estudos prévios calculou a EGE usando métodos ecocardiográficos. Não há consenso quanto à fase do ciclo cardíaco em que se deve medir a EGE. Embora alguns estudos sugiram que tais medidas devam ser tomadas no final da sístole,7,11,12 um maior número recomenda que sejam realizadas ao final da diástole.5-8

O presente estudo visou a determinar se a EGE ao final da sístole ou da diástole acha-se mais intimamente associada com pacientes com infarto do miocárdio sem supradesnivelamento do segmento ST (IMSSST) de alto risco segundo o SG.

 Métodos

Este estudo observacional prospectivo foi realizado entre outubro de 2012 e fevereiro de 2013. Os pacientes apresentando IMSSST pela primeira vez foram incluídos. Foram excluídos aqueles com doença pulmonar crônica, doença hepática crônica, doença inflamatória reumática, doença muscular, insuficiência cardíaca, insuficiência renal crônica (creatinina > 2,5 mg/dL), miocardite e cardiomiopatia.

Diagnosticou-se IMSSST na presença de um padrão de angina acelerada ou prolongada ou recorrente tanto de repouso quanto durante os mínimos esforços nas últimas 48-72 horas, com níveis de troponina ou creatino quinase-MB (CK-MB) acima dos limites superiores da normalidade. Os parâmetros bioquímicos foram avaliados em amostras de sangue coletadas durante a hospitalização. Os níveis máximos de cTnI e CK-MB foram identificados durante o seguimento das enzimas cardíacas.

Usou-se um programa de computador (www.outcomes-umassmed.org/grace/acs_risco) para calcular o SG. Idade, pressão arterial sistólica, nível sérico de creatinina e classificação de Killip foram determinados para o SG. Os seguintes dados foram utilizados no programa de computador: parada cardíaca na admissão, alterações do segmento ST, método de revascularização e informação sobre elevação das enzimas cardíacas. Após o cálculo dos valores do SG, os pacientes foram divididos em grupos conforme a recomendação das diretrizes da AHA e da ESC sobre IMSSST.1,2

Os pacientes com SG intra-hospitalar de baixo a moderado (< 140) foram classificados como o grupo SG-BM (n = 70), e aqueles com SG intra-hospitalar alto (> 140), como grupo SG-A (n = 92).

Ecocardiografia

As características basais clínicas (frequência cardíaca, pressão arterial, eletrocardiografia, parâmetros bioquímicos laboratoriais, angiografia), ecocardiográficas e demográficas (idade, sexo, altura, peso) dos pacientes foram registradas. A variável preditora foi o SG, e a variável desfecho primário foi a EGE.

Realizou-se análise ecocardiográfica na posição de decúbito lateral esquerdo conforme a recomendação das diretrizes da Sociedade Americana de Ecocardiografia, nas primeiras 24 horas de terapia intensiva, usando o sistema de ultrassom cardiovascular Vivid S5 (General Electric Vingmed Ultrasound, Horten, Noruega). A gordura epicárdica foi definida como um espaço "sem eco" entre a parede externa do miocárdio e a camada visceral do pericárdio. O maior diâmetro da gordura epicárdica localizada na parede livre do ventrículo direito (VD) foi determinado. A EGE foi medida no corte longitudinal parasternal no final da sístole e no final da diástole em três ciclos cardíacos. A média dos três ciclos cardíacos foi usada para a análise estatística.

A fração de ejeção (FE) ventricular esquerda foi determinada usando-se o método de Simpson modificado. Para uma melhor avaliação das funções do VD, calculou-se a excursão sistólica do plano anular tricúspide (TAPSE) a partir do anel lateral tricúspide.13 A FEVD foi calculada com ecocardiografia 3D, usando-se o método de somação de discos. O índice de desempenho miocárdico, conhecido como índice Tei, é uma estimativa global das duas funções do VD. O índice Tei é um índice de intervalo de tempo derivado do Doppler, que combina o desempenho cardíaco sistólico e diastólico. O índice Tei é facilmente derivado usando-se ecocardiografia Doppler convencional pulsada, como previamente descrito por Tei et al.14

O presente estudo foi planejado e conduzido de acordo com a Declaração de Helsinque, tendo seu protocolo sido aprovado pelo Comitê de Ética.

 Análise de variabilidade

As variabilidades intra- e inter-observador foram verificadas para os dados ecocardiográficos obtidos para um subgrupo de 40 indivíduos. Um dia depois, o primeiro operador repetiu a análise para avaliar a variabilidade intra-observador. Para avaliar a variabilidade inter-observador, um segundo operador cego para as medidas anteriores verificou cada parâmetro dois dias mais tarde. A análise de concordância para variabilidade intra- e inter-observador das medidas de EGE revelou um alto nível de concordância com diferença média de 0,26 (limite de concordância 95%: -0,5 a 0,93) e coeficiente de correlação intraclasse de 0,918 (IC 95%: 0,830-0,960).

 Análise estatística

Os dados categóricos são apresentados como frequências (porcentagens) e as variáveis contínuas, como média ± DP. O teste de Kolmogorov-Smirnov foi usado para avaliar se os dados tinham uma distribuição normal. Como a distribuição foi normal, usou-se o teste t para amostras independentes para a análise estatística. Realizou-se o teste do qui-quadrado para as variáveis categóricas. Coeficientes de correlação intraclasse e análise de Bland-Altman foram usados para as medidas ecocardiográficas para avaliar a reprodutibilidade intra- e inter-observador, respectivamente. O teste de Pearson foi usado para analizar a correlação entre SG e EGE. Construiu-se curva receiver operating characteristic (ROC) para determinar se a EGE podia predizer os grupos de alto risco com base no SG. Um p bicaudal < 0,05 foi considerado estatisticamente significativo.

 Resultados Dados demográficos e características basais

Este estudo avaliou 207 pacientes admitidos com IMSSST, sendo 45 excluídos devido às seguintes condições: doença pulmonar crônica, 22 pacientes; doença hepática crônica, 2; insuficiência cardíaca prévia, 10; insuficiência renal crônica, 8; miocardite, 2; e cardiomiopatia, 1. No total, 162 pacientes foram incluídos no estudo (115 homens; idade média, 63,9±12,8 anos). Com base no SG intra-hospitalar, 70 pacientes foram classificados como do grupo SG-BM, e 92, como do grupo SG-A. A idade média foi maior no grupo SG-A (73,7 ± 10,5 vs. 57,2 ± 9,1 anos; p < 0,001). A pressão arterial sistólica média (147,3 ± 27,7 vs. 130,3 ± 31,1 mmHg; p < 0,001) e a pressão arterial diastólica média (85,5 ± 16,1 vs. 78,1 ± 19,5 mmHg; p = 0,010) foram mais altas no grupo SG-BM. Não houve diferença entre os grupos quanto ao índice de massa corporal, tabagismo e número de pacientes com hipertensão e diabetes mellitus. Taxa de mortalidade [3 (4,3%) vs. 13 (14,1%); p = 0,037], permanência na unidade de terapia intensiva [3,3 ± 1,2 dias vs. 4,3 ± 2,9 dias; p = 0,019] e permanência total hospitalar [5,6 ± 2,5 dias vs. 6,9 ± 3,8 dias; p = 0,020] foram significativamente mais altas no grupo SG-A do que no grupo SG-BM (Tabela 1).

Características gerais dos pacientes com infarto miocárdico sem supradesnivelamento do segmento ST de acordo com o escore GRACE intra-hospitalar
Grupo de risco baixo-a-moderado (n = 70) Grupo de risco alto (n = 92) Valor de p
Idade, anos 57,2 ± 9,1 73,7 ± 10,5 p < 0,001
Sexo, masculino/feminino 56/14 59/33 p = 0,027
Pressão arterial sistólica, mmHg 147,3 ± 27,7 130,3 ± 31,1 p < 0,001
Pressão arterial diastólica, mmHg 85,5 ± 16,1 78,1 ± 19,5 p = 0,010
Índice de massa corporal, kg/m2 28,5 ± 4,4 26,7 ± 3,7 p = 0,060
Tabagismo, n (%) 35 (50%) 50 (54,1%) p = 0,583
Hipertensão, n (%) 40 (57,1%) 44 (47,8%) p = 0,299
Diabetes mellitus, n (%) 21 (30,0%) 33 (35,9%) p = 0,376
Glicemia na admissão, mg/dL 139,6 ± 60,3 146,5 ± 70,3 p = 0,515
Colesterol total, mg/dL 185,7 ± 44,9 204,2 ± 55,9 p = 0,022
LDL colesterol, mg/dL 133,1 ± 37,9 148,5 ± 43,9 p = 0,019
HDL colesterol, mg/dL 40,9 ± 15,9 39,9 ± 9,8 p = 0,627
Triglicerídeos, mg/dL 124,8 ± 71,4 131,3 ± 96,8 p = 0,641
Proteína C Reativa, mg/dL 1,63 ± 3,4 2,68 ± 4,38 p = 0,013
Creatinina, mg/dL 0,84 ± 0,2 1,18 ± 0,57 p < 0,001
Troponina I, ng/mL 31,6 ± 30,0 31,1 ± 28,1 p = 0,951
Fração de ejeção VE, % 47,8 ± 10,2 43,3 ± 10,5 p = 0,008
Septo interventricular, mm 10,1 ± 1,2 10,1 ± 1,36 p = 0,726
Parede posterior, mm 9,8 ± 1,12 9,9 ± 1,26 p = 0,761
Mass VE, g 181,5 ± 44,2 198,7 ± 49,3 p = 0,019
Índice de massa VE, g/m2 94,3 ± 22,4 109,4 ± 28,4 p = 0,002
Espessura da gordura epicárdica (sístole), cm 0,72 ± 0,17 0,81 ± 0,12 p < 0,001
Espessura da gordura epicárdica (diástole), cm 0,46 ± 0,13 0,54 ± 0,10 p < 0,001
PSAP, mmHg 25,1 ± 7,5 30,7 ± 8,7 p < 0,001
TAPSE, mm 20,9 ± 4,1 19,4 ± 3,6 p = 0,017
Fração de ejeção VD, % 53,1 ± 5,3 50,1 ± 5,4 p = 0,001
Índice Tei 0,35 ± 0,09 0,44 ± 0,11 p < 0,001
Escore SYNTAX 20,6 ± 10,1 21,2 ± 9,9 p = 0,625
Lesão na DAE, n (%) 29 (41,4%) 35 (38,0%) p = 0,744
Lesão na Cx, n (%) 17 (24,3%) 16 (17,4%) p = 0,280
Lesão na CD, n (%) 24 (34,3%) 41 (44,6%) p = 0,149
Mortalidade, n (%) 3 (4,3%) 13 (14,1%) p = 0,037
Permanência em UTI, dias 3,3 ± 1,2 4,3 ± 2,9 p = 0,019
Total de hospitalização, dias 5,6 ± 2,5 6,9 ± 3,8 p = 0,020

Dados apresentados como média ± DP ou número (porcentagem)

*Testes do qui-quadrado e t de amostras independentes

VE: ventrículo esquerdo; VD: ventrículo direito; Cx: artéria circunflexa; HDL: lipoproteína de alta densidade; DAE: artéria descendente anterior esquerda; LDL: lipoproteína de baixa densidade; CD: artéria coronária direita; PSAP: pressão sistólica da artéria pulmonar; TAPSE: excursão sistólica do plano anular tricúspide; UTI: unidade de terapia intensiva.

 Achados laboratoriais

A avaliação de dados laboratoriais não revelou diferença entre a média dos valores de glicemia pós-prandial, HDL-colesterol, triglicerídeos e cTn-I. As médias dos valores de colesterol total (204,2 ± 55,9 vs. 185,7 ± 44,9 mg/dL, p = 0,022), LDL-colesterol (148,5 ± 43,9 vs. 133,1 ± 37,9 mg/dL, p = 0,019), proteína C reativa (2,68 ± 4,38 vs. 1,63 ± 3,4 mg/L, p = 0,013) e creatinina (1,18 ± 0,57 vs. 0,84 ± 0,20 mg/dL, p < 0,001) foram maiores no grupo SG-A do que no grupo SG-BM (Tabela 1).

Ecocardiografia e angiografia coronariana

Os grupos não diferiram quanto a septo interventricular e espessura da parede posterior. A FE foi mais baixa no grupo SG-A (43,3% ± 10,5 vs. 47,8% ± 10,2, p = 0,008). A EGE no final da sístole (0,81 ± 0,12 vs. 0,72 ± 0,17 cm, p < 0,001), a EGE no final da diástole (0,54 ± 0,10 vs. 0,46 ± 0,13 cm, p < 0,001) e a pressão sistólica da artéria pulmonar (PSAP) (30,7 ± 8,7 vs. 25,1 ± 7,5 mmHg, p < 0,001) foram mais altas no grupo SG-A. A FEVD, um dos indicadores da função sistólica do VD (50,1% ± 5,4 vs. 53,1% ± 5,3, p = 0,001), e a TAPSE (19,4 ± 3,6 vs. 20,9 ± 4,1, p = 0,017) foram mais baixas no grupo SG-A do que no grupo SG-BM (Tabela 1). O índice Tei foi significativamente mais alto no grupo SG-A (0,48 ± 0,09 vs. 0,39 ± 0,08, p < 0,001).

Os angiogramas não mostraram diferença significativa entre os envolvimentos das artérias descendente anterior esquerda (DAE), circunflexa (Cx) e coronária direita (CD) (Tabela 1).

Correlação e análise ROC

Com base no SG intra-hospitalar, realizou-se a análise ROC para calcular a EGE para predição dos pacientes de alto risco. O valor de corte da EGE no final da sístole para o grupo SG-A foi de 0,765 cm (AUC: 0,699; IC 95%: 0,613-0,785; sensibilidade, 67%; especificidade, 64%) e o valor de corte da EGE no final da diástole foi de 0,468 cm para o grupo SG-A (AUC: 0,709; IC 95%: 0,621-0,797; sensibilidade, 68%; especificidade, 72%) (Tabela 2, Figura 1).

De acordo com o escore GRACE intra-hospitalar (SG), realizou-se análise <italic>receiver operating characteristic</italic> (ROC) para calcular a espessura da gordura epicárdica (EGE) para predição de pacientes de alto risco
Corte (cm) Sensibilidade Especificidade AUC Intervalo de confiança 95%
EGE final da sístole / SG 0,765 67% 64% 0,699 0,613-0,785
EGE final da diástole / SG 0,468 68% 72% 0,709 0,621-0,797

AUC (Area Under the Curve): área sob a curva.

Curva receiver operating characteristic (ROC). O ponto de corte da espessura da gordura epicárdica ao final da sístole para o grupo SG-A foi calculado em 0,765 cm (AUC: 0,699; IC 95%: 0,613-0,785; sensibilidade, 67%; especificidade, 64%). O ponto de corte da espessura da gordura epicárdica ao final da diástole para o grupo SG-A foi calculado em 0,468 cm (AUC: 0,709; IC 95%: 0,621-0,797; sensibilidade, 68%; especificidade, 72%). [AUC (area under the curve): área sob a curva; IC: intervalo de confiança; SG-A: escore GRACE alto)

O coeficiente de correlação (r) do SG intra-hospitalar e a EGE no final da sístole foi de 0.387, enquanto o coeficiente de correlação (r) do SG intra-hospitalar e a EGE no final da diástole foi de 0,438 (Tabela 3).

Tabela de correlação para o escore GRACE intra-hospitalar (SG), escore SYNTAX e medidas de espessura da gordura epicárdica (EGE)
Coeficiente de correlação (r) Valor de p
EGE final da sístole - SG r = 0,387 < 0,001
EGE final da diástole - SG r = 0,438 < 0,001
EGE final da sístole - escore SYNTAX r = 0,285 0,009
EGE final da diástole - escore SYNTAX r = 0,292 0,002

Análise de correlação de Pearson

 Discussão

Este estudo visou a mostrar a relação entre o SG e a EGE de pacientes admitidos no nosso centro com o diagnóstico de IMSSST. Este estudo demonstrou que a EGE acha-se associada com SG aumentado, e a análise estatística sugere que seria mais conveniente medir a EGE ao final da diástole.

O sistema SG foi inicialmente usado para a avaliação prognóstica de pacientes com SCA após o estudo multinacional Global Registry of Acute Coronary Events (GRACE).15,16 A detecção de um alto SG está associada com mau prognóstico. Atualmente, as diretrizes de SCA recomendam seu uso para avaliação de risco. As diretrizes para diagnóstico e tratamento de SCA da AHA e da ESC fornecem sugestões de como interpretar o SG. De acordo com essas recomendações, um SG intra-hospitalar > 140 indica alta morbimortalidade. Tais diretrizes recomendam revascularização precoce para pacientes de alto risco.1,2 O nosso estudo identificou uma alta taxa de mortalidade (p = 0,001) no grupo SG-A com SG > 140. Além da taxa de mortalidade, os parâmetros ecocardiográficos caíram no grupo SG-A. Os valores de FEVE do grupo SG-A foram mais baixos do que aqueles do grupo SG-BM. A FEVD e a TAPSE, marcadores da função sistólica do VD, mostraram-se reduzidas no grupo SG-A. O índice Tei e a PSAP mostraram-se aumentadas no grupo SG-A.

A gordura epicárdica é um tipo de tecido adiposo visceral que se estende ao longo das artérias coronárias nos sulcos atrioventricular e interventricular. O miocárdio e o tecido adiposo epicárdico encontram-se em contato direto, sendo o suprimento sanguíneo para esses tecidos fornecido pelo mesmo sistema coronariano.17 Assim, funcionando como um órgão endócrino, o tecido adiposo epicárdico pode afetar direta e indiretamente as artérias coronárias e as estruturas cardíacas. O tecido adiposo epicárdico pode produzir várias citocinas que estimulam angiogênese, inflamação, estresse oxidativo e aterosclerose. Vários estudos clínicos recentes foram realizados para investigar a relação entre EGE e doenças cardiovasculares. Como resultado desses estudos, uma EGE aumentada foi associada com um aumento do risco de doença cardiovascular.5-7,11,18-22 A EGE acha-se aumentada nos pacientes com inflamação, idade avançada, obesidade, hipercolesterolemia, hipertensão, fibrilação atrial, diabetes mellitus e síndrome metabólica.3,4,10,23-27 No nosso estudo, não houve diferença significativa entre os grupos quanto a glicemia e índice de massa corporal. O número de pacientes com diagnóstico de síndrome metabólica, diabetes e hipertensão foi similar entre os grupos (Tabela 1).

Há diversas recomendações para a medida da EGE. Prefere-se usar a parede livre do VD como local de medida da EGE, cujo cálculo é geralmente realizado no final da diástole.5,8 Entretanto, algumas publicações sugerem que a EGE possa também ser medida ao final da sístole.7,11,12 Recomenda-se a medida da EGE ao final da sístole durante o ciclo cardíaco devido à compressão durante a diástole. No presente estudo, valores médios de EGE foram obtidos empregando-se pelo menos três diferentes medidas para o final da sístole e o final da diástole, sendo os valores médios de EGE mais altos no grupo SG-A do que no grupo SG-BM (p < 0,001) (Tabela 1). Observou-se correlação entre o SG intra-hospitalar e a EGE (SG intra-hospitalar e EGE no final da sístole, r = 0,387; final da diástole, r = 0,438). As análises ROC demonstraram que a EGE ao final da diástole foi melhor preditora de alto SG do que a EGE ao final da sístole (Tabela 2, Figura 1).

Limitações do estudo

A principal limitação do presente estudo é o relativamente pequeno tamanho da amostra. Também, a ecocardiografia é menos precisa do que as demais técnicas radiológicas para a avaliação do tecido adiposo epicárdico, embora uma boa correlação com a RNM tenha sido observada. Ainda, relatou-se uma correlação moderada com o volume de gordura epicárdica avaliado com RNM cardiovascular. A despeito do baixo nível de acurácia, a medida da EGE através de ecocardiografia é mais viável do através de RNM.

 Conclusões

Estudos prévios mostraram EGE aumentada em várias condições e patologias que podem dificultar as funções cardíacas. No nosso estudo, as taxas de mortalidade e morbidade estavam aumentadas no grupo SG-A. O SG mostrou uma correlação positiva com EGE ao final da sístole e EGE ao final da diástole. As avaliações estatísticas demonstraram uma melhor correlação entre SG e EGE ao final da diástole do que EGE ao final da sístole.

Concluindo, o cálculo da EGE ao final da diástole pode fornecer informação útil em pacientes com alto SG durante a avaliação ecocardiográfica de IMSSST.

Fontes de financiamento

O presente estudo não teve fontes de financiamento externas.

Vinculação acadêmica

Não há vinculação deste estudo a programas de pós‑graduação.