Arq Bras Cardiol abc Arquivos Brasileiros de Cardiologia Arq. Bras. Cardiol. 0066-782X 1678-4170 Sociedade Brasileira de Cardiologia - SBC QDnLndjF88GgpyxSsVqfz3w S0066-782X2018000300219 10.5935/abc.20180042 Original Article Echocardiography - Adults Subclinical Anthracycline-Induced Cardiotoxicity in the Long - Term Follow-Up of Lymphoma Survivors: A Multi-Layer Speckle Tracking Analysis Kang Yu 1 * Xiao Fei 2 * Chen Haiyan 3 * Wang Wei 1 Shen Lijing 2 Zhao Hang 1 Shen Xuedong 1 Chen Fangyuan 2 He Ben 1 Shanghai Jiaotong University School of Medicine Renji Hospital Shanghai China Department of Cardiology - Renji Hospital - School of Medicine - Shanghai Jiaotong University, Shanghai - China Shanghai Jiaotong University Shanghai Jiaotong University School of Medicine Renji Hospital Shanghai China Department of Hemotology - Renji Hospital - School of Medicine - Shanghai Jiaotong University, Shanghai - China Shanghai Jiaotong University Fudan University Zhongshan Hospital Department of Echocardiography China Department of Echocardiography - Zhongshan Hospital of Fudan University, Shanghai - China Fudan University

Yu Kang, Fei Xiao and Haiyan Chen contribute equally to the work.

 Mailing Address: Fangyuan Chen and Ben He, Department of Hemotology - Renji Hospital - School of Medicine - Shanghai Jiaotong University. No. 1630 Dongfang Rd, 200126, Shanghai - China. E-mail: chenfangyuan1027@163.com; heben1027@163.com

Author contributions

Conception and design of the research: Kang Y, Shen X; Acquisition of data: Kang Y, Xiao F Xiao F, Chen H, Wang W, Zhao H; Analysis and interpretation of the data: Kang Y, Chen H, Wang W; Statistical analysis: Kang Y, Xiao F, Chen H, Shen L, Zhao H; Obtaining financing: Chen F, He B; Writing of the manuscript: Kang Y, Chen H, Shen L; Critical revision of the manuscript for intellectual content: Chen F, He B.

Potential Conflict of Interest

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

 03 2018 110 3 219 228 11 07 2017 05 09 2017 06 10 2017 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:

Anthracycline generates progressive left ventricular dysfunction associated with a poor prognosis.

 Objectives:

The purpose of this study was to evaluate whether layer-specific strain analysis could assess the subclinical left ventricular dysfunction after exposure to anthracycline.

 Methods:

Forty-two anthracycline-treated survivors of large B-cell non-Hodgkin lymphoma, aged 55.83 ± 17.92 years (chemotherapy group) and 27 healthy volunteers, aged 51.39 ± 13.40 years (control group) were enrolled. The cumulative dose of epirubicin in chemotherapy group was 319.67 ± 71.71mg/m2. The time from last dose of epirubicin to the echocardiographic examination was 52.92 ± 22.32 months. Global longitudinal (GLS), circumferential (GCS) and radial strain (GRS), subendocardial, mid and subepicardial layer of longitudinal (LS-ENDO, LS-MID, LS-EPI) and circumferential strain (CS-ENDO, CS-MID, CS-EPI) values were analyzed. Transmural strain gradient was calculated as differences in peak systolic strain between the subendocardial and subepicardial layers. A value of p < 0.05 was considered significant.

 Results:

Conventional parameters of systolic and diastolic function showed no significant difference between two groups. Compared with controls, patients had significantly lower GCS and GLS. Multi-layer speckle tracking analysis showed significant reduction of circumferential strain of subendocardial layer, transmural CS gradient and longitudinal strain of all three layers. In contrast, the two groups did not differ in transmural longitudinal strain gradient and radial strains.

 Conclusions:

It proved the preferential impairment of subendocardial deformation in long-term survivors after exposure to anthracycline. Multi-layer speckle tracking echocardiography might facilitate the longitudinal follow-up of this at-risk patient cohort.

 Keywords: Cardiotoxicity Anthracyclines Lymphoma, Non-Hodgkin Hematologic Neoplasias/drug therapy Echocardiography National Nature Science Foundation of China 81401411 Nature Science Foundation of Shanghai 14ZR1425200 16ZR1420600 This work was supported by grants from the National Nature Science Foundation of China (81401411) and Nature Science Foundation of Shanghai (14ZR1425200, 16ZR1420600). Introduction

Anthracycline, a commonly used chemotherapeutic agent in the treatment of a wide spectrum of hematologic malignancies and solid tumors, is undermined by potential life-threatening cardiotoxicity.1,2 Anthracycline-induced left ventricular dysfunction is believed to be refractory to conventional pharmacological therapy and to be associated with a poor prognosis. Therefore, detection of subclinical myocardial dysfunction is of vital importance to balance between the cardiac risk and the potential cancer treatment.

Two-dimensional speckle tracking echocardiography, based on tracking local image details from frame to frame throughout the cardiac cycle,3-6 has allowed more accurate measurements of regional myocardial systolic performance.

It has been proved that patients treated with epirubicin-based chemotherapy experienced significant decrease in strain values while LVEF remained stable and within normal limits.7,8 Based on the 2D speckle tracking technology, a novel offline tool is recently introduced which has a potential of measuring strains in subendocardial and subepicardial layers comparatively.

Therefore, the objectives of this study were to evaluate whether layer-specified systolic strain analysis could differentiate the subclinical left ventricular function changes in patients after exposure to anthracycline-based chemotherapy.

Methods Study population

A total of 45 anthracycline-treated survivors of histopathologically confirmed large B-cell non-Hodgkin lymphoma who have been off treatment for at least one year were enrolled in this study between March 2014 and Dec 2015 (chemotherapy group). Exclusion criteria were uncontrolled hypertension, significant valvular disease, congenital disease, a widened QRS complex on surface ECG, arrhythmia, a previous history of heart failure and/or coronary artery disease. The following data were collected including date of completion of chemotherapy, duration of follow-up, cumulative doses of anthracyclines, symptoms and signs of heart failure, and cardiac medications. Twenty-eigh age-matched and gender-matched referred to our hospital for non-specific chest pain or palpitation, but with no history of cardiovascular disease patients and with completely normal electrocardiograms, echocardiograms, treadmill stress exercises and 24-hour, continuous ambulatory electrocardiograms were selected as controls (control group).

 Echocardiographic imaging

Images were obtained in the left lateral decubitus position with Vivid E9 (GE Healthcare, Horton, Norway) ultrasound systems. Standard two-dimensional images were acquired according to recommendations of the American Society of Echocardiography.9 Depth was minimized to optimize the frame rate. At least three beats were digitally stored for offline analysis. Left ventricular ejection fraction was calculated using the modified Simpson's biplane method. Left ventricular mass index, relative wall thickness, transmitral peak early (E) and peak late (A) diastolic filling velocities were also measured. Tissue Doppler echocardiography was performed with the sample volume positioned at the basal LV free wall and septum at the mitral annular junction to obtain lateral and septal mitral annular systolic (S') and early diastolic myocardial tissue velocities (E').

 Multi-layer speckle tracking echocardiography

Gray scale images for offline speckle tracking analysis were acquired at frame rate of 53 to 84 MHz. Echopac version 11.1 (GE Healthcare, Horton, Norway) was used for multi-layer strain analysis. The automatic tracking analysis was performed in the apical 4-chamber, 2-chamber, long-axis apical view for longitudinal strain and in the parasternal short-axis view at basal, mid-papillary and apical level for circumferential and radial strain according to the vendor's instructions. The endocardial border was manually traced at end-diastole. The ROI (region of interest) for strain analysis was adjusted manually. The locations of the tracking points were adjusted when necessary so that the region of interest extended from endocardial to epicardial borders to approximate the myocardium, which was divided into subendocardial, middle and subepicardial myocardium layers of equal thickness.

Peak circumferential (CS) and radial strain (RS) measurements were obtained from the basal, mid-segments of the septal, lateral, inferior, anterior, anteroseptal, posterior walls, apical segments of anterior, inferior, septal, lateral walls, totally 18 segments. Peak longitudinal strain (LS) measurements were obtained from the basal, mid- and apical segments of the anterior, inferior, anteroseptal, anterolateral, inferoseptal, inferolateral walls, totally 16 segments. In each segment, the subendocardial, middle and subepicardial LS and CS were calculated automatically. Regional strain values were averaged to determine global longitudinal/circumferential/radial strain (GLS, GCS, GRS), global subendocardial, middle and subepicardial LS (LS-ENDO, LS-MID, LS-EPI) and CS (CS-ENDO, CS-MID, CS-EPI). Transmural strain gradient was calculated as differences of peak systolic strain between the subendocardial and subepicardial layers. Strain values of each level were calculated.

 Reproducibility

Intra- and inter-observer reproducibility was assessed by calculating the difference between the values of 10 randomly selected patients measured by one observer twice and by a second observer.

 Statistical analysis

Continuous variables with normal distribution were expressed as the mean ± standard deviation. Continuous variables with non-normal distribution were expressed as median and interquartile range. Differences between two groups were determined using independent samples t test for continuous variables with normal distribution and Kruskal Wallis test for with non-normal distribution. One sample K-S test was used in determining the normality of data. One way ANOVA test was used to compare the differences between strain values of different layers and different levels within each group. Relations between strain values and cumulative anthracycline dose were determined by Pearson correlation analysis. Interobserver and intraobserver reproducibility of strain values were assessed using intraclass correlation coefficients (ICCs) and Bland-Altman analysis. Data were analyzed by SPSS version 16.0 (SPSS, Inc, Chicago, IL, USA).

A value of p < 0.05 was considered significant.

 Results

Three patients and one healthy volunteer were excluded from the analysis because of poor image quality (defined as > 2 non-visualized segments). Forty-two patients, 18 males, ranging in age from 22 to 77 years (mean age 55.83 ± 17.92 years), and 27 healthy volunteers, 14 males, ranging in age from 32 to 77 years (mean age 51.39 ± 13.40 years), were finally included in the statistical analysis. Table 1 shows the two groups clinical characteristics. In all patients, the cumulative dose of epirubicin was 319.67 ± 71.71 mg/m2 (ranging from 150.94 mg/m2 to 440.00 mg/m2). Patients have not received radiotherapy or other cardiotoxic agents. No patient complained of cardiovascular related symptoms. EKG remained normal in all patients. The time from last dose of epirubicin to the echocardiographic examination was 52.92 ± 22.32 months (ranging from 24 months to 104 months).

Clinical characteristics of two groups
Normal Chemotherapy p value
Number 27 42
Male (n/%) 12 (44.44) 18 (42.86) 0.84
Age (y) 50.39 ± 13.40 55.83 ± 17.92 0.16
Hypertension (n/%) 0(0) 4(9.52)
ACEI (n/%) 0(0) 1(2.38)
ARB (n/%) 0 (0) 1(2.38)
CCB (n/%) 0(0) 0(0)
β-blocker (n/%) 0(0) 1(2.38)
Smoker (n/%) 5(17.24) 9(21.42) 0.470
DM (n/%) 0(0) 1(2.38)
SBP (mmHg) 124.8 ± 12.6 121.6 ± 12.5 0.627
DBP (mmHg) 70.7 ± 9.3 69.5 ± 7.9 0.233
HR (bpm) 78.0 ± 11.3 81.0 ± 14.5 0.099

ACEI: angiotensin-converting enzyme inhibitors; ARB: angiotensin receptor blockers; CCB: calcium-channel blocker; DBP: diastolic blood pressure; DM: diabetes mellitus; HR: heart rate; SBP: systolic blood pressure; p values were assessed by independent samples t test

 Conventional echocardiographic parameters

Table 2 summarized the echocardiographic findings in the two groups. Conventional parameters of systolic and diastolic function, including body surface area indexed left ventricular end-diastolic volume (LVEDV/BSA), body surface area indexed left ventricular end-systolic volume (LVESV/BSA), left ventricular ejection fraction, E velocity, A velocity, E/A ratio, deceleration time, S' velocity, E/E', isovolumic relaxation time showed no significant difference between two groups.

Conventional echocardiographic parameters between two groups.
Normal Chemotherapy p value
LVEDV/BSA (ml) 47.22 ± 13.97 46.99 ± 13.99 0.95
LVESV/BSA (ml) 16.31 ± 6.24 16.30 ± 6.47 0.99
LVMI (g/m2) 79.32 ± 16.66 71.87 ± 13.68 0.13
RWT 0.36 ± 0.05 0.36 ± 0.05 0.93
LVEF (%) 66.46 ± 5.55 66.04 ± 6.52 0.78
E velocity (m/s) 80.38 ± 24.11 72.45 ± 16.99 0.11
A velocity (m/s) 76.62 ± 17.76 76.61 ± 19.07 0.95
E/A ratio 1.11 ± 0.44 1.01 ± 3.53 0.32
S' velocity (m/s) 9.50 ± 2.19 9.24 ± 2.08 0.60
E/E' ratio 6.95 ± 3.21 6.71 ± 2.31 0.71
DT (ms) 145.88 ± 27.81 149.95 ± 34.28 0.61
IVRT (ms) 85.36 ± 20.14 88.13 ± 24.77 0.62

BSA: body surface area; DT: deceleration time; FS: fraction shortening; LVEDV: left ventricular end-diastolic volume; LVEF: left ventricular ejection fraction; LVESV: left ventricular end-systolic volume; LVMI: left ventricular mass index; IVRT: isovolumic relaxation time; RWT: relative wall thickness; p values were assessed by independent samples t test

 Multi-layer speckle tracking echocardiography

In both groups, longitudinal and circumferential strains were highest in the apical region and decreased significantly from apical to basal level (Table 3,4). The left ventricular longitudinal and circumferential strains of different myocardial layers in patients and controls are shown in Table 5, Figure 1. Transmural strain gradients in LS and CS were demonstrated in both patients and controls, with strain values decreasing from the subendocardial to subepicardial layers. GCS was significantly decreased in chemotherapy group respect to control group (-27.73% ± 3.37% vs -24.94% ± 4.14%, p = 0.004). The reduction of GCS was attributable to significantly reduced CS-ENDO but preserved CS-EPI strain in patients compared with controls. The longitudinal strain values of global left ventricle and all three layers were significantly decreased in chemotherapy group. However, the two groups did not differ in transmural longitudinal strain gradient. In contrast, there was no statistic difference in radial strains between the two groups.

Three-layer circumferential strain values between two groups stratified by levels
CS-Endo(%) CS-Mid(%) CS-Epi(%)
Control Chemotherapy P value Control Chemotherapy P value Control Chemotherapy p value
Basal level -33.48 ± 5.10 -26.26 ± 4.34 0.000 -23.95 ± 4.26 -22.37 ± 4.28 0.149 -17.58 ± 4.03 -16.85 ± 3.93 0.453
Mid level -34.29 ± 4.21 -31.25 ± 5.39 0.014 -24.45 ± 3.46 -22.57 ± 3.67 0.053 -17.54 ± 3.21 -16.85 ± 3.94 0.063
Apical level -44.31 ± 6.14 -41.13 ± 9.47 0.038 -30.32 ± 4.46 -28.91 ± 6.34 0.316 -21.77 ± 3.95 -19.81 ± 5.39 0.105
P value 0.000 0.000 0.000 0.000 0.000 0.000

CS-ENDO: subendocardial circumferential strain; CS-EPI: subepicardial circumferential strain; CS-MID: middle circumferential strain. P values were analyzed by one way ANOVA test.

 Three-layer longitudinal strain values between two groups stratified by levels
LS-Endo(%) LS-Mid(%) LS-Epi(%)
Control Chemotherapy P value Control Chemotherapy P value Control Chemotherapy p value
Basal level -18.51 ± 2.55 -16.82 ± 2.36 0.006 -17.74 ± 2.50 -16.49 ± 2.11 0.027 -17.07 ± 2.50 -15.63 ± 2.00 0.009
Mid level -22.76 ± 2.72 -21.04 ± 2.87 0.014 -20.82 ± 2.39 -19.45 ± 2.49 0.028 -19.23 ± 2.56 -16.87 ± 2.26 0.000
Apical level -34.36 ± 3.23 -32.29 ± 5.69 0.101 -26.20 ± 3.06 -25.08 ± 4.23 0.623 -20.8 ± 2.55 -19.53 ± 5.12 0.538
P value 0.000 0.000 0.000 0.000 0.000 0.000

LS-ENDO: subendocardial longitudinal strain; LS-EPI: subepicardial longitudinal strain; LS-MID: middle longitudinal strain. P values were analyzed by one way ANOVA test.

 Strain values between two groups.
Control Chemotherapy p value
GLS (%) -21.86 ± 2.38 -20.36 ± 2.58 0.016*
GCS (%) -27.73 ± 3.37 -24.94 ± 4.14 0.004*
GRS (%) 31.44 ± 12.98 26.89 ± 9.75 0.118
LS-ENDO(%) -25.21 ± 2.72 -23.38 ± 3.11 0.014*
LS-MID(%) -21.53 ± 2.36 -20.35 ± 2.58 0.029*
LS-EPI(%) -18.83 ± 2.19 -17.35 ± 2.48 0.013*
LS gradient (%) -6.38 ± 1.28 -6.03 ± 2.07 0.439
CS-ENDO(%) -37.37 ± 3.79 -32.88 ± 5.23 0.000*
CS-MID(%) -26.24 ± 2.98 -24.62 ± 4.13 0.073
CS-EPI(%) -19.56 ± 4.45 -17.32 ± 4.13 0.066
CS gradient(%) -17.80 ± 3.69 -15.55 ± 4.59 0.0*

CS-ENDO: subendocardial circumferential strain; CS-EPI: subepicardial circumferential strain; CS-MID: middle circumferential strain; GCS: global circumferential strain; GLS: global longitudinal strain; GRS: global radial strain; LS-ENDO: subendocardial longitudinal strain; LS-EPI: subepicardial longitudinal strain; LS-MID: middle longitudinal strain.

p < 0.05. p values were assessed by independent samples t test

Strain values between two groups. *:p < 0.05.

There was no correlation between anthracycline dose and layer specific strain values.

 Inter and intra-observer variation

Inter-observer measurement showed ICC = 0.91 for CS-ENDO, 0.83 for CS-MID, 0.91 for CS-EPI, 0.95 for GCS, 0.61 for RS, 0.87 for LS-ENDO, 0.85 for LS-MID, 0.90 for LS-EPI, 0.91 for GLS. Similarly, intra-observer measurement showed ICC = 0.96 for CS-ENDO, 0.89 for CS-MID, 0.97 for CS-EPI, 0.97 for GCS, 0.73 for RS, 0.86 for LS-ENDO, 0.85 for LS-MID, 0.82 for LS-EPI, 0.94 for GLS, indicating satisfactory reproducibility by speckle-tracking-derived multilayer analysis of circumferential and longitudinal strain values. Bland-Altman curves of strain values were shown on Figure 2.

Bland-Altman analysis of inter-, intra-observation reproducibility.

Discussion

Globally, cancer is diagnosed in 12.7 million people annually, with its incidence projected to increase by 40% in high-income countries from 2008 to 2030.10

Anthracyclines are powerful cytotoxic agents, available to treat a wide spectrum of hematologic malignancies and solid tumors. However, life altering cardiac sequelae from anthracyclines remain a problem, with a range of 5-23% of patients developing late-onset heart failure secondary to anthracycline induced-cardiotoxicity.11

Reliable, sensitive and non-invasive methods in detecting cardiac function are of vital importance in these patients. The present study demonstrated that subclinical cardiotoxicity existed in long-survivors after receiving anthracycline therapy albeit normal conventional echocardiographic findings, implicating the more sensitive nature of these parameters in monitoring anthracycline cardiotoxicity.

Recently tagged magnetic resonance imaging provided a detailed quantitative analysis of left ventricular transmural differences in myocardial deformation.12 Echocardiographic speckle-tracking strain analysis, which is angle-independent, provides a noninvasive method to assess left ventricular mechanics, thus translating clinically relevant aspects of cardiac performance from "bench to bedside". Furthermore, the echocardiographic speckle tracking derived transmural gradients has recently been validated against sonomicrometry crystal in a sheep model.13 As proved by previous studies,14-16 our observations showed great interobserver and intraobserver agreement, suggesting reasonable reproducibility of the speckle tracking-derived multi-layer strain parameters.

The present study confirmed the presence of transmural and translevel gradient in myocardial circumferential and longitudinal strains, with higher values in the subendocardial myocardial layer and in the apical level in both normal subjects and patients exposed to anthracycline, as is improved by Shi et al.16 The difference in amplitude of myocardial contraction between the subendocardial and subepicardial regions was related to the orientation pattern of myocardial fiber in the heart. It has been described that in normal heart, contraction is greater in the subendocardial myocardium layer than in the subepicardial myocardium layer.17 However, with greater contraction and higher energy requirements, subendocardial layer was more susceptible to injury, which can be detected by multi-layer speckle tracking strain analysis. Beck et al.18 has demonstrated that a multi-layer analysis of myocardial deformation is highly accurate in the differentiation between different degrees of scar transmurality as assessed by MRI. In particular, multi-layer strain analysis provided higher accuracy to discriminate nontransmural versus noninfarction or trasmural versus nontransmural infarction compared with global strain. Altiok et al.19 has also found that circumferential endocardial strain analysis allowed accurate distinction between segments with non-transmural infarction vs those with no infarction and between segments with transmural vs non-transmural infarction as defined by late gadolinium enhancement cardiovascular magnetic resonance. In the present study, we adopted a multi-layer strain approach in analyzing layer-specific ventricular deformation and observed the decrease of subendocardial circumferential strain values and transmural circumferential gradient in long-term survivors exposed to anthracycline. It has been proved in animal models of anthracycline cardiotoxicity that severe myocytolysis mainly involved the subendocardium of the ventricle.20 Moreover, Perel et al.21 observed a regional and diffuse pattern of subendocardial enhancement using cardiac magnetic resonance imaging in patients with anthracycline-induced cardiomyopathy. Hence, the findings in our study of reduction of subendocardial circumferential strain values and transmural circumferential gradient but preserved subepicardial circumferential strain was consistent with the same hypothesis of subendocardial injury induced by anthracycline. Moreover, it has been proved22 that in patients with chronic ischemic cardiomyopathy, subendocardial circumferential strain was a powerful predictor of cardiac events and appeared to be a better parameter than LVEF and other strain variables analyzed by echocardiography. Therefore, we believed that further importance may need to be attached to the changes of subendocardial circumferential strains.

We observed that after anthracycline exposure, longitudinal strains of all the three layers decreased significantly. However, transmural longitudinal strain gradient did not show any difference compared to normal group. It is reported that the subendocardium is predominantly composed of longitudinal myocardial fiber. The subendocardial deformation is greatest in the longitudinal direction and verifies the endo-epicardial gradient in normal left ventricles on magnetic resonance imaging.23,24 Hence, the longitudinal left ventricular mechanics are predominantly governed by the subendocardial region of the myocardium, which probably accounts for our findings of the reduction of all three layers of longitudinal strain values and the absence of difference in longitudinal transmural gradient.

The lack of difference in radial strain between two groups in our study was perhaps not surprising, which was concordance with some previous studies.25,26 It was recently published that peak radial strain differed largely between different software and algorithms, and small changes in width can change large RS differences.27 In the present study, the interobserver variation did not show satisfactory reproducibility of RS measurement. Hence, it may suggest that indices of radial deformation are not as sensitive as circumferential and longitudinal strains in detecting subclinical left ventricular dysfunction.

The absence of associations between strain parameters and cumulative anthracycline indicated lack of a safe dose that was free of cardiotoxicity. It has been proved that even children who have received a cumulative doxorubicin dose as low as 45mg/m2 have reduced left ventricular mass28 and anthracycline damage to all cardiac structures may begin with the first anthracycline dose.29

Limitation

Several limitations to this study warranted comment. This was a cross-sectional study of a relatively small patient cohort, which did not provide information on the value of myocardial deformation parameters in prognostication. Further out-come studies with hard clinical endpoints will be required to determine the clinical significance of our findings. Secondly, although speckle tracking echocardiography allows interrogation of global strain, these parameters are not entirely load dependent and need to be interpreted with caution when an alteration of cardiac status with acute changes in load is anticipated.

 Conclusion

Despite normal left ventricular ejection fraction, subtle abnormalities in myocardial systolic function were present in long-term survivors after anthracycline exposure. It provided the evidence of preferential impairment of subendocardial deformation in long-term survivors after exposure to anthracycline. Multi-layer speckle tracking echocardiography, a potential non-invasive tool for the detection of subclinical anthracycline-induced myocardial abnormalities, might facilitate the longitudinal follow-up of this at-risk patient cohort.

Sources of Funding

This work was supported by grants from the National Nature Science Foundation of China (81401411) and Nature Science Foundation of Shanghai (14ZR1425200, 16ZR1420600).

Study Association

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

Ethics approval and consent to participate

This study was approved by the Ethics Committee of the Renji Hospital under the protocol number 2014(N012). All the procedures in this study were in accordance with the 1975 Helsinki Declaration, updated in 2013. Informed consent was obtained from all participants included in the study.

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Int J Cardiol. 2015 Apr 1;184:237-43. doi: 10.1016/j.ijcard.2015.01.070 Ozawa K Funabashi N Takaoka H Kamata T Kanaeda A Saito M Characteristic myocardial strain identified in hypertrophic cardiomyopathy subjects with preserved left ventricular ejection fraction using a novel multi-layer transthoracic echocardiography technique Int J Cardiol 2015 04 01 184 237 243 10.1016/j.ijcard.2015.01.070 15 Götte MJ, Germans T, Rüssel IK, Zwanenburg JJ, Marcus JT, van Rossum AC, et al. Myocardial strain and torsion quantified by cardiovascular magnetic resonance tissue tagging: studies in normal and impaired left ventricular function. J Am Coll Cardiol. 2006;48(10):2002-11. doi: 10.1016/j.jacc.2006.07.048 Götte MJ Germans T Rüssel IK Zwanenburg JJ Marcus JT van Rossum AC Myocardial strain and torsion quantified by cardiovascular magnetic resonance tissue tagging: studies in normal and impaired left ventricular function J Am Coll Cardiol 2006 48 10 2002 2011 10.1016/j.jacc.2006.07.048 16 Shi J, Pan C, Kong D, Cheng L, Shu X. Left Ventricular longitudinal and circumferential layer-specific myocardial strains and their determinants in healthy subjects. Echocardiography. 2016;33(4):510-8. doi: 10.1111/echo.13132. Shi J Pan C Kong D Cheng L Shu X Left Ventricular longitudinal and circumferential layer-specific myocardial strains and their determinants in healthy subjects Echocardiography 2016 33 4 510 518 10.1111/echo.13132 17 Tsutsui H, Uematsu M, Yamagishi M, Haruta S, Shimakura T, Miyatake K. Usefulness of the subendocardial myocardial velocity gradient in low-dose dobutamine stress echocardiography. Heart Vessels. 2000;15(1):11-7. PMID: 11001480. Tsutsui H Uematsu M Yamagishi M Haruta S Shimakura T Miyatake K. Usefulness of the subendocardial myocardial velocity gradient in low-dose dobutamine stress echocardiography Heart Vessels 2000 15 1 11 17 11001480 18 Becker M, Ocklenburg C, Altiok E, Füting A, Balzer J, Krombach G, et al. Impact of infarct transmurality on layer specific impairment of myocardial function. Eur Heart J. 2009;30(12):1467-76. doi: 10.1093/eurheartj/ehp112 Becker M Ocklenburg C Altiok E Füting A Balzer J Krombach G Impact of infarct transmurality on layer specific impairment of myocardial function Eur Heart J 2009 30 12 1467 1476 10.1093/eurheartj/ehp112 19 Altiok E, Neizel M, Tiemann S, Krass V, Becker M, Zwicker C, et al. Layer-specific analysis of myocardial deformation for assessment of infarct transmurality: comparison of strain encoed cardiovascular magnetic resonance with 2D speckle tracking echocardiography. Eur Heart J Cardiovasc Imaging. 2013;14(6):570-8. doi: 10.1093/ehjci/jes229. Altiok E Neizel M Tiemann S Krass V Becker M Zwicker C Layer-specific analysis of myocardial deformation for assessment of infarct transmurality: comparison of strain encoed cardiovascular magnetic resonance with 2D speckle tracking echocardiography Eur Heart J Cardiovasc Imaging 2013 14 6 570 578 10.1093/ehjci/jes229 20 Milei J, Boveris A, Llesuy S, Molina HA, Storino R, Ortega D, et al. Amelioration of adriamycin-induced cardiotoxicity in rabbits by prenylamine and vitamins A and E. Am Heart J. 1986;111(1):95-102. Doi: http://dx.doi.org/10.1016/0002-8703(86)90559-4 Milei J Boveris A Llesuy S Molina HA Storino R Ortega D Amelioration of adriamycin-induced cardiotoxicity in rabbits by prenylamine and vitamins A and E Am Heart J 1986 111 1 95 102 Doi: http://dx.doi.org/10.1016/0002-8703(86)90559-4 21 Perel RD, Slaughter RE, Strugnell WE. Subendocardial late gadolinium enhancement in two patients with anthracycline cardiotoxicity following treatment for Edwig's sarcomea. J Cardiovasc Magn Reson. 2006;8(6):789-91. doi: 10.1080/10976640600737664. Perel RD Slaughter RE Strugnell WE Subendocardial late gadolinium enhancement in two patients with anthracycline cardiotoxicity following treatment for Edwig's sarcomea J Cardiovasc Magn Reson 2006 8 6 789 791 10.1080/10976640600737664 22 Hamada S, Schroeder J, Hoffmann R, Altiok E, Keszei A, Almalla M, et al. Prediction of outcomes in patients with chronic ischemic cardiomyopathy by layer-specific strain echocardiography: a proof of concept. J Am Soc Echocardiogr. 2016;29(5):412-20. doi: 10.1016/j.echo.2016.02.001. Hamada S Schroeder J Hoffmann R Altiok E Keszei A Almalla M Prediction of outcomes in patients with chronic ischemic cardiomyopathy by layer-specific strain echocardiography: a proof of concept J Am Soc Echocardiogr 2016 29 5 412 420 10.1016/j.echo.2016.02.001 23 Hashimoto I, Li X, Hejmadi Bhat A, Jones M, Zetts AD, Sahn DJ. Myocardial strain rate is a superior method for evaluation of left ventricular subendocardial function compared with tissue Doppler imaging. J Am Coll Cardiol. 2003;42(9):1574-83. Doi: https://doi.org//10.1016/j.jacc.2003.05.002 Hashimoto I Li X Hejmadi Bhat A Jones M Zetts AD Sahn DJ Myocardial strain rate is a superior method for evaluation of left ventricular subendocardial function compared with tissue Doppler imaging J Am Coll Cardiol 2003 42 9 1574 1583 Doi: https://doi.org//10.1016/j.jacc.2003.05.002 24 Moore CC, Lugo-Olivieri CH, McVeigh ER, Zerhouni EA. Three-dimensional systolic strain patterns in the normal human left ventricle: characterization with tagging MR imaging. Radiology. 2000;214(2):453-66. doi: 10.1148/radiology.214.2.r00fe17453 Moore CC Lugo-Olivieri CH McVeigh ER Zerhouni EA Three-dimensional systolic strain patterns in the normal human left ventricle: characterization with tagging MR imaging Radiology 2000 214 2 453 466 10.1148/radiology.214.2.r00fe17453 25 Cheung YF, Hong WJ, Chan GC, Wong SJ, Ha SY. Left ventricular myocardial deformation and mechanical dyssynchrony in children with normal ventricular shortening fraction after anthracycline therapy. Heart. 2010;96(14):1137-41. doi: 10.1136/hrt.2010.194118. Cheung YF Hong WJ Chan GC Wong SJ Ha SY Left ventricular myocardial deformation and mechanical dyssynchrony in children with normal ventricular shortening fraction after anthracycline therapy Heart 2010 96 14 1137 1141 10.1136/hrt.2010.194118 26 Tassan-Mangina S, Codorean D, Metivier M, Costa B, Himberlin C, Jouannaud C, et al. Tissue Doppler imaging and conventional echocardiography after anthracycline treatment in adults: early and late alterations of left ventricular function during a prospective study. Eur J Echocardiogr. 2006;7(2):141-6. doi: 10.1016/j.euje.2005.04.009. Tassan-Mangina S Codorean D Metivier M Costa B Himberlin C Jouannaud C Tissue Doppler imaging and conventional echocardiography after anthracycline treatment in adults: early and late alterations of left ventricular function during a prospective study Eur J Echocardiogr 2006 7 2 141 146 10.1016/j.euje.2005.04.009 27 Biaggi P, Carasso S, Garceau P, Greutmann M, Gruner C, Tsang W, et al. Comparison of two different speckle tracking software systems: does the method matter? Echocardiography. 2011;28(5):539-47. doi: 10.1111/j.1540-8175.2011.01386.x. Biaggi P Carasso S Garceau P Greutmann M Gruner C Tsang W Comparison of two different speckle tracking software systems: does the method matter? Echocardiography 2011 28 5 539 547 10.1111/j.1540-8175.2011.01386.x 28 Lipshultz SE, Lipsitz SR, Sallan SE, Dalton VM, Mone SM, Gelber RD, et al. Chronic progressive cardiac dysfunction years after doxorubicin therapy for childhood acute lymphoblastic leukemia.. 2005;23(12):2629-36. doi: 10.1200/JCO.2005.12.121. Lipshultz SE Lipsitz SR Sallan SE Dalton VM Mone SM Gelber RD Chronic progressive cardiac dysfunction years after doxorubicin therapy for childhood acute lymphoblastic leukemia 2005 23 12 2629 2636 10.1200/JCO.2005.12.121 29 Lipshultz SE, Rifai N, Sallan SE, Lipsitz SR, Dalton V, Sacks DB, et al. Predictive value of cardiac troponin T in pediatric patients at risk for myocardial injure. Circulation. 1997;96(8):2641-8. Doi: https://doi.org/10.1161/01.CIR.96.8.2641 Lipshultz SE Rifai N Sallan SE Lipsitz SR Dalton V Sacks DB Predictive value of cardiac troponin T in pediatric patients at risk for myocardial injure Circulation 1997 96 8 2641 2648 Doi: https://doi.org/10.1161/01.CIR.96.8.2641 Artigo Original Ecocardiografia Adultos Cardiotoxicidade Subclínica Induzida por Antraciclina no Seguimento a Longo Prazo de Sobreviventes de Linfoma: Uma Análise Speckle Tracking Multi-Layer Kang Yu 1 * Xiao Fei 2 * Chen Haiyan 3 * Wang Wei 1 Shen Lijing 2 Zhao Hang 1 Shen Xuedong 1 Chen Fangyuan 2 He Ben 1 Department of Cardiology - Renji Hospital - School of Medicine - Shanghai Jiaotong University, Shanghai - China Department of Hemotology - Renji Hospital - School of Medicine - Shanghai Jiaotong University, Shanghai - China Department of Echocardiography - Zhongshan Hospital of Fudan University, Shanghai - China

Yu Kang, Fei Xiao e Haiyan Chen contribuíram igualmente para o estudo

 Correspondência: Fangyuan Chen e Ben He, Department of Hemotology - Renji Hospital - School of Medicine - Shanghai Jiaotong University. No. 1630 Dongfang Rd, 200126, Shanghai - China. E-mail: chenfangyuan1027@163.com

Contribuição dos autores

Concepção e desenho da pesquisa: Kang Y, Shen X; Obtenção de dados: Kang Y, Xiao F, Chen H, Wang W, Zhao H; Análise e interpretação dos dados: Kang Y, Xiao F, Chen H, Wang W; Análise estatística: Kang Y, Xiao F, Chen H, Shen L, Zhao H; Obtenção de financiamento: Chen F, He B; Redação do manuscrito: Kang Y, Xiao F, Chen H, Shen L; Revisão crítica do manuscrito quanto ao conteúdo intelectual importante: Chen F, He B.

Potencial conflito de interesses

Declaro não haver conflito de interesses pertinentes.

 Resumo Fundamentos:

A antraciclina gera uma disfunção ventricular esquerda progressiva associada a um prognóstico ruim.

 Objetivos:

O propósito deste estudo foi avaliar se a análise layer específico de strain poderia avaliar disfunção ventricular esquerda subclínica após exposição a antraciclina.

 Métodos:

Foram inscritos quarenta e dois sobreviventes tratados com antraciclina por linfoma não Hodgkin de células B grandes, de 55,83 ± 17,92 anos (grupo de quimioterapia) e 27 voluntários saudáveis, de 51,39 ± 13,40 anos (grupo controle). A dose cumulativa de epirrubicina no grupo de quimioterapia foi de 319,67 ± 71,71 mg/m2. O tempo desde a última dose de epirrubicina até o exame ecocardiográfico foi de 52,92 ± 22,32 meses. Analisaram-se o strain longitudinal global (GLS), o circunferencial (GCS) e o strain radial (GRS), os valores das camadas subendocárdica, média e subepicárdica so strain longitudinal (LS-ENDO, LS-MID, LS-EPI) e do strain circunferencial (CS-ENDO, CS-MID, CS-EPI). O gradiente de strain transmural foi calculado como a diferença no strain sistólico pico entre as camadas subendocárdicas e subepicárdicas. Um valor de p < 0,05 foi considerado significativo.

 Resultados:

Os parâmetros convencionais da função sistólica e diastólica não mostraram diferenças significativas entre dois grupos. Comparados aos controles, os pacientes apresentaram GCS e GLS significativamente menores. A análise de speckle tracking multi-layer mostrou uma redução significativa no strain circunferencial da camada subendocárdica, o gradiente transmural CS e o strain longitudinal das três camadas. Em contraste, os dois grupos não diferiram no gradiente de strain longitudinal transmural e de strain radiais.

 Conclusões:

Provou-se a deterioração preferencial do strain subendocárdico em sobreviventes de longa duração após exposição à antraciclina. O ecocardiograma de speckle tracking multi-layer pode facilitar o acompanhamento longitudinal dessa coorte de pacientes em risco. (Arq Bras Cardiol. 2018; 110(3):219-228)

 Palavras-chave: Cardiotoxicidade Antraciclinas Linfoma Não Hodgkin Neoplasias Hematológicas/quimioterapia Ecocardiografia National Nature Science Foundation of China 81401411 Nature Science Foundation of Shanghai 14ZR1425200 16ZR1420600 O presente estudo foi financiado pelo National Nature Science Foundation of China (81401411) e Nature Science Foundation of Shanghai (14ZR1425200, 16ZR1420600). Introdução

A antraciclina, um agente quimioterapêutico de uso comum no tratamento de um amplo espectro de neoplasias hematológicas e tumores sólidos, é prejudicada por uma potencial cardiotoxicidade eventualmente fatal.1,2 A disfunção ventricular esquerda induzida por antraciclina é considerada refratária à terapia farmacológica convencional e associada a um mau prognóstico. Portanto, a detecção de disfunção miocárdica subclínica é de vital importância para o equilíbrio entre o risco cardíaco e o potencial tratamento do câncer.

O ecocardiograma bidimensional de speckle tracking, baseado em detalhes de imagens do tracking local quadro a quadro ao longo do ciclo cardíaco,3-6 permitiu medidas mais precisas do desempenho sistólico regional do miocárdio. Demonstrou-se que os pacientes tratados com quimioterapia à base de epirrubicina apresentaram uma diminuição significativa nos valores de strain, enquanto que a FEVE permaneceu estável e dentro dos limites normais.7,8 Com base na tecnologia de speckle tracking 2D, uma nova ferramenta off-line foi recentemente introduzida que tem o potencial de medir strains em camadas subendocárdicas e subepicárdicas comparativamente.

Portanto, os objetivos deste estudo foram avaliar se a análise layer específico de strain sistólico poderia diferenciar alterações subclínicas da função ventricular esquerda em pacientes após exposição a quimioterapia à base de antraciclina.

 Métodos Estudo da população

Um total de 45 sobreviventes tratados com antraciclina por grande linfoma não-Hodgkin de células B confirmado histopatologicamente e que não foram tratados há pelo menos um ano foram incluídos neste estudo entre março de 2014 e dezembro de 2015 (grupo de quimioterapia). Os critérios de exclusão foram hipertensão não controlada, doença valvular severa, doença congênita, complexo QRS alargado em ECG de superfície, arritmia, antecedentes de insuficiência cardíaca e/ou doença arterial coronariana. Um total de 28 pacientes pareados por idade e gênero encaminhados ao hospital por dor no peito não específica ou palpitações, mas sem história de doença cardiovascular e com eletrocardiogramas, ecocardiogramas, exercício de esforço na esteira, e eletrocardiogramas ambulatórios continuo de 24 horas foram selecionados como controles (grupo controle). Todos os assuntos deram consentimento informado, e o comitê de ética em pesquisa do hospital Renji aprovou o protocolo.

 Imagem ecocardiográfica

As imagens foram obtidas na posição de decúbito lateral esquerdo com sistemas de ultra-som Vivid E9 (GE Healthcare, Horton, Noruega). As imagens bidimensionais padrão foram adquiridas de acordo às recomendações da Sociedade Americana de Ecocardiografia.9 A profundidade foi minimizada para otimizar a taxa de velocidade. Pelo menos três batidas foram armazenadas digitalmente para análise off-line. A fração de ejeção do ventrículo esquerdo foi calculada usando o método de biplano Simpson modificado. O índice de massa de ventrículo esquerdo, a espessura relativa da parede (ERP), as velocidades de enchimento diastólico precoce (E) e o pico tardio (A) também foram medidas. O ecocardiograma Doppler tecidual foi realizado com o volume da amostra posicionado na parede livre basal do VE e o septo na junção anular mitral para obter a velocidade sistólica anular mitral lateral (S ') e a velocidade tecidual miocárdica diastólica precoce (E').

 Ecocardiografía de multi-layer speckle tracking

Imagens de escala de cinza para análises speckle tracking offline foram adquiridas a taxa de quadros de 53 a 84 MHz. Foi utilizado Echopac versão 11.1 (GE Healthcare, Horton, Noruega) para a análise multi-layer do strain. A análise de tracking automático foi realizada na vista apical de 4 câmaras, de 2 câmaras e de eixo longo para o strain longitudinal e na vista parasternal do eixo curto no nível basal, médio-papilar e apical para o strain circunferencial e radial de acordo com a instruções do vendedor.

A borda endocárdica foi traçada manualmente no final da diástole. A ROI (região de interesse) para análise de strain foi ajustada manualmente. A localização dos pontos de tracking foi ajustada quando necessário para que a região de interesse se estendesse das bordas endocárdicas às epicárdicas para aproximar o miocárdio, o qual foi dividido em camadas de miocárdio subendocárdico, médio e subepicárdico de igual espessura.

As medidas de strain circunferencial pico (CS) e de strain radial (RS) foram obtidas a partir dos segmentos basal, médio do septal, lateral, inferior, anterior, anteroseptal, paredes posteriores, segmentos apicais de paredes laterais anterior, inferior, septal, em total 18 segmentos. As medidas de strain longitudinal pico (LS) foram obtidas a partir dos segmentos basal, médio e apical das paredes inferiores anterior, inferior, anteroseptal, anterolateral, inferoseptal e inferolateral, em total 16 segmentos. Em cada segmento, os LS e CS subendocárdicos, médios e subepicárdicos foram calculados automaticamente. Os valores do strain regional foram calculados para determinar o strain global longitudinal/circunferencial/radial (GLS, GCS, GRS), LS y CS globais, subendocárdicos, médios e subepicárdicos (LS-ENDO, LS-MID, LS-EPI), (CS-ENDO, CS -MID, CS-EPI). O gradiente de strain transmural foi calculado como diferenças do strain sistólica pico entre as camadas subendocárdicas e subepicárdicas. Os valores de strain de cada nível foram calculados.

 Reprodutibilidade

A reprodutibilidade intra e inter-observador foi avaliada calculando a diferença entre os valores de 10 pacientes selecionados aleatoriamente, medidos por um observador duas vezes e por um segundo observador.

 Análise estatística

As variáveis contínuas com distribuição normal foram expressas como média ± desvio padrão. As variáveis contínuas com distribuição não normal foram expressas como intervalo mediano e interquartil. As diferenças entre os dois grupos foram determinadas por meio do teste t de amostras independentes para as variáveis contínuas com distribuição normal e o teste de Kruskal Wallis para a distribuição não normal. O teste K-S de uma amostra foi utilizado para determinar a normalidade dos dados. O teste de ANOVA de uma via foi utilizado para comparar as diferenças entre os valores de strain de diferentes camadas e diferentes níveis dentro de cada grupo. As relações entre os valores do strain e a dose cumulativa de antraciclina foram determinadas pela análise de correlação de Pearson. A reprodutibilidade interobservador e intraobservador de valores de strain foi avaliada utilizando coeficientes de correlação intraclasse (ICCs) e a análise de Bland-Altman. Os dados foram analisados pela SPSS versão 16.0 (SPSS, Inc, Chicago, IL, EUA).

Um valor de p < 0,05 foi considerado significativo.

 Resultados

Três pacientes e um voluntário saudável foram excluídos da análise devido à má qualidade da imagem (definida como > 2 segmentos não visualizados). Um total de 42 pacientes, 18 do sexo masculino, com idade entre 22 e 77 anos (idade média 55,83 ± 17,92 anos) e 27 voluntários saudáveis, 14 homens, com idade entre 32 e 77 anos (idade média 51,39 ± 13,40 anos), foram finalmente incluídos na análise estatística. A Tabela 1 mostra as características clínicas dos dois grupos. Em todos os pacientes, a dose cumulativa de epirrubicina foi de 319,67 ± 71,71 mg/m2 (variando de 150,94 mg/m2 a 440,00 mg/m2). Os pacientes não receberam radioterapia ou outros agentes cardiotóxicos. Nenhum paciente se queixou de sintomas cardiovasculares relacionados. O EKG permaneceu normal em todos os pacientes. O tempo desde a última dose de epirrubicina até o exame ecocardiográfico foi de 52,92 ± 22,32 meses (variando de 24 meses a 104 meses).

Características clínicas dos dois grupos
Normal Quimioterapia Valor de p
Número 27 42
Masculino (n/%) 12 (44,44) 18 (42,86) 0,84
Idade (a) 50,39 ± 13,40 55,83 ± 17,92 0,16
Hipertensão (n/%) 0(0) 4(9,52)
IECA (n/%) 0(0) 1(2,38)
BRA (n/%) 0 (0) 1(2,38)
BCC (n/%) 0(0) 0(0)
β-bloqueador (n/%) 0(0) 1(2,38)
Fumante (n/%) 5(17,24) 9(21,42) 0,470
DM (n/%) 0(0) 1(2,38)
PAS (mmHg) 124,8 ± 12,6 121,6 ± 12,5 0,627
PAD (mmHg) 70,7 ± 9,3 69,5 ± 7,9 0,233
FC (bpm) 78,0 ± 11,3 81,0 ± 14,5 0,099

IECA: inibidores da enzima conversora da angiotensina; BRA: bloqueadores dos receptores da angiotensina; BCC: bloqueador de canais de cálcio; PAD: pressão arterial diastólica; DM: diabetes mellitus; FC: frequência cardíaca; PAS: pressão arterial sistólica; os valores de p foram avaliados por teste t de amostras independentes.

 Parâmetros ecocardiográficos convencionais

A Tabela 2 resume os achados ecocardiográficos nos dois grupos. Os parâmetros convencionais da função sistólica e diastólica, incluindo o volume diastólico do ventrículo esquerdo indexado para a área da superfície corporal (VDF/BSA), o volume sistólico do ventrículo esquerdo indexado para a área de superfície corporal (VSF/BSA), fracção de ejecção do ventrículo esquerdo, velocidade E, velocidade A, razão E/A, tempo de desaceleração, velocidade S', E/E', o tempo de relaxamento isovolumétrico não mostrou nenhuma diferença significativa entre dois grupos.

Parâmetros ecocardiográficos convencionais entre dois grupos
Normal Quimioterapia Valor de p
VDFVE/ASC (ml) 47,22 ± 13,97 46,99 ± 13,99 0,95
VSFVE/ASC (ml) 16,31 ± 6,24 16,30 ± 6,47 0,99
IMVE (g/m2) 79,32 ± 16,66 71,87 ± 13,68 0,13
ERP 0,36 ± 0,05 0,36 ± 0,05 0,93
FEVE (%) 66,46 ± 5,55 66,04 ± 6,52 0,78
Velocidade E (m/s) 80,38 ± 24,11 72,45 ± 16,99 0,11
Velocidade A (m/s) 76,62 ± 17,76 76,61 ± 19,07 0,95
Razão E/A 1,11 ± 0,44 1,01 ± 3,53 0,32
Velocidade S'(m/s) 9,50 ± 2,19 9,24 ± 2,08 0,60
Razão E/E' 6,95 ± 3,21 6,71 ± 2,31 0,71
TD (ms) 145,88 ± 27,81 149,95 ± 34,28 0,61
TRIV (ms) 85,36 ± 20,14 88,13 ± 24,77 0,62

ASC: área de superfície corporal; TD: tempo de desaceleração; RF: redução de fração; VDFVE: volume diastólico final do ventrículo esquerdo; FEVE: fração de ejeção do ventrículo esquerdo; VSFVE: volume sistólico final do ventrículo esquerdo; IMVE: índice de massa do ventrículo esquerdo; TRIV: tempo de relaxamento isovolumétrico; ERP: espessura relativa da parede; os valores de p foram avaliados por teste t de amostras independentes.

 Ecocardiografia multi-layer speckle tracking

Em ambos os grupos, os strains longitudinal e circunferencial foram maiores na região apical e diminuíram significativamente do nível apical para o nível basal (Tabela 3 e 4). A Tabela 5, Figura 1 mostra os strains longitudinal e circunferencial do ventrículo esquerdo de diferentes camadas miocárdicas em pacientes e controles. Os gradientes de strain transmural LS e CS foram demonstrados em pacientes e controles, com valores de strain que diminuem das camadas subendocárdicas para subepicárdicas. O GCS diminuiu significativamente no grupo de quimioterapia em relação ao grupo de controle (-27,73 ± 3,37% -24,94%% vs ± 4,14%, p = 0,004). A redução do GCS foi atribuída ao CS-ENDO significativamente reduzido, mas preservou o strain CS-EPI em pacientes em comparação com os controles. Os valores de strain longitudinal do ventrículo esquerdo global e as três camadas diminuíram significativamente no grupo de quimioterapia. No entanto, os dois grupos não diferiram no gradiente de strain transmural longitudinal. Pelo contrário, não houve diferença estatística nos strains radiais entre os dois grupos.

Valores de strain circunferencial de três camadas entre dois grupos estratificados por níveis
CS-Endo(%) CS-Mid(%) CS-Epi(%)
Controle Quimioterapia Valor de p Controle Quimioterapia Valor de p Controle Quimioterapia Valor de p
Nível basal -33,48 ± 5,10 -26,26 ± 4,34 0,000 -23,95 ± 4,26 -22,37 ± 4,28 0,149 -17,58 ± 4,03 -16,85 ± 3,93 0,453
Nível médio -34,29 ± 4,21 -31,25 ± 5,39 0,014 -24,45 ± 3,46 -22,57 ± 3,67 0,053 -17,54 ± 3,21 -16,85 ± 3,94 0,063
Nível apical -44,31 ± 6,14 -41,13 ± 9,47 0,038 -30,32 ± 4,46 -28,91 ± 6,34 0,316 -21,77 ± 3,95 -19,81 ± 5,39 0,105
Valor P 0,000 0,000 0,000 0,000 0,000 0,000

CS-ENDO: strain circunferencial subendocárdico; CS-EPI: strain circunferencial subepicárdica; CS-MID: strain circunferencial do meio. Os valores de P foram analisados por teste ANOVA de via única.

 Valores de strain longitudinal de três camadas entre os dois grupos estratificados por níveis
LS-Endo(%) LS-Mid(%) LS-Epi(%)
Controle Quimioterapia Valor de p Controle Quimioterapia Valor de p Controle Quimioterapia Valor de p
Nível basal -18,51 ± 2,55 -16,82 ± 2,36 0,006 -17,74 ± 2,50 -16,49 ± 2,11 0,027 -17,07 ± 2,50 -15,63 ± 2,00 0,009
Nível médio -22,76 ± 2,72 -21,04 ± 2,87 0,014 -20,82 ± 2,39 -19,45 ± 2,49 0,028 -19,23 ± 2,56 -16,87 ± 2,26 0,000
Nível apical -34,36 ± 3,23 -32,29 ± 5,69 0,101 -26,20 ± 3,06 -25,08 ± 4,23 0,623 -20,8 ± 2,55 -19,53 ± 5,12 0,538
Valor P 0,000 0,000 0,000 0,000 0,000 0,000

LS-ENDO: strain longitudinal subendocárdico; LS-EPI: strain longitudinal subepicárdico; LS-MID: strain longitudinal do meio. Os valores de P foram analisados por teste ANOVA de via única.

 Valores de strain entre os dois grupos.
Controle Quimioterapia Valor de p
GLS (%) -21,86 ± 2,38 -20,36 ± 2,58 0,016*
GCS (%) -27,73 ± 3,37 -24,94 ± 4,14 0,004*
GRS (%) 31,44 ± 12,98 26,89 ± 9,75 0,118
LS-ENDO(%) -25,21 ± 2,72 -23,38 ± 3,11 0,014*
LS-MID(%) -21,53 ± 2,36 -20,35 ± 2,58 0,029*
LS-EPI(%) -18,83 ± 2,19 -17,35 ± 2,48 0,013*
Gradiente LS (%) -6,38 ± 1,28 -6,03 ± 2,07 0,439
CS-ENDO(%) -37,37 ± 3,79 -32,88 ± 5,23 0,000*
CS-MID(%) -26,24 ± 2,98 -24,62 ± 4,13 0,073
CS-EPI(%) -19,56 ± 4,45 -17,32 ± 4,13 0,066
Gradiente CS (%) -17,80 ± 3,69 -15,55 ± 4,59 0,0*

CS-ENDO: strain circunferencial subendocárdico; CS-EPI: strain circunferencial subepicárdico; CS-MID: strain circunferencial do meio; GCS: strain circunferencial global; GLS: strain longitudinal global; GRS: strain radial global; LS-ENDO: strain longitudinal subendocárdico; LS-EPI: strain longitudinal subepicárdica; LS-MID: strain longitudinal do meio.

p < 0,05. Os valores de p foram avaliados por teste t de amostras independentes.

Valores de strain entre os dois grupos. *: p < 0,05.

Não houve correlação entre a dose de antraciclina e os valores layer específico do strain.

 Variação inter e intraobservador

A medição inter-observador mostrou CCI = 0,91 para CS-endo, 0,83 para CS-MID 0,91 para CS-EPI, 0,95 para GCS, 0,61 para RS, 0,87 para LS-ENDO, 0,85 para LS-MID, 0,90 para LS-EPI, 0,91 para GLS. Do mesmo modo, a medição intra-observador mostrou CCI = 0,96 para CS-endo, 0,89 para CS-MID, 0,97 para CS-EPI, 0,97 para GCS, 0,73 para RS, 0,86 para LS-ENDO, 0,85 para LS-MID, 0,82 para LS-EPI, 0,94 para GLS, indicando uma reprodutibilidade satisfatória através de análise derivada speckle-tracking multilayer dos valores de strain longitudinal e circunferencial. As curvas de strain de Bland-Altman são mostradas na Figura 2.

Análise de Bland-Altman da reprodutibilidade inter-intra-observação.

Discussão

Globalmente, o câncer é diagnosticado em 12,7 milhões de pessoas por ano, com uma incidência projetada para aumentar em 40% em países de alta renda de 2008 para 2030.10

As antraciclinas são poderosos agentes citotóxicos, disponíveis para tratar um amplo espectro de neoplasias hematológicas e tumores sólidos. No entanto, as sequelas cardíacas das antraciclinas continuam a ser um problema, com uma gama de 5 a 23% dos pacientes que desenvolvem insuficiência cardíaca de início tardio secundária à cardiotoxicidade induzida por antraciclina.11

Métodos confiáveis, sensíveis e não invasivos na detecção da função cardíaca são de vital importância nestes pacientes. O presente estudo demonstrou que a cardiotoxicidade subclínica existia em sobreviventes longos após ter recebido tratamento com antraciclina, embora fossem achados ecocardiográficos convencionais normais, implicando a natureza mais sensível desses parâmetros no monitoramento de cardiotoxicidade por antraciclina.

Recentemente, a ressonância magnética proporcionou uma análise quantitativa detalhada das diferenças transmurais do ventrículo esquerdo na deformação miocárdica.12 Análise de ecocardiografia de speckle-tracking do strain, o qual é independente do ângulo, fornece um meio não invasivo para avaliar a mecânica do ventrículo esquerdo, traduzindo aspectos clinicamente relevantes do desempenho cardíaco do "laboratório ao paciente". Além disso, os gradientes transmurais derivados da ecocardiografia de speckle-tracking foram recentemente validados contra o cristal de sonomicrometría em um modelo de ovelha.13 Conforme demonstrado em estudos prévios,14-16 as nossas observações mostraram alta concordância inter e intra-observador, sugerindo uma reprodutibilidade razoável dos parâmetros do strain derivados do speckle tracking multi-layer.

O presente estudo confirmou a presença de gradiente transmural e transnível em strains miocárdicos longitudinais e circunferenciais, com valores mais elevados na camada miocárdica subendocárdica e no nível apical tanto nos indivíduos normais quanto nos pacientes expostos à antraciclina, como é melhorado por Shi et al.,16 A diferença no grau de contração do miocárdio entre as regiões subendocárdicas e subepicárdicas estava relacionada com o padrão de orientação das fibras do miocárdio no coração. Foi descrito que no coração normal, a contração é maior na camada de miocárdio subendocárdico do que na camada miocárdica subepicárdica.17 No entanto, com maior contração e maiores necessidades energéticas, a camada subendocárdica foi mais suscetível a lesões, o que pode ser detectado por análise de strain multi-layer speckle tracking speckle tracking. Beck et al.,18 demostraram que uma análise multi-layer do strain miocárdico é altamente precisa na diferenciação entre os diferentes graus de transmuralidade da cicatriz avaliada pela MRI. Em particular, a análise de strain multi-layer proporcionou uma maior precisão para discriminar infarto não-transmural versus não infarto ou infarto transmural versus não-transmural em comparação com a strain global. Altiok et al.,19 descobriu também que a análise do strain circunferencial endocárdico permitiu uma distinção clara entre os segmentos com infarto não transmural vs aqueles sem infarto e entre segmentos com infarto transmural vs não transmural como é definido por posterior ressonância magnética cardiovascular com realce de gadolínio. No presente estudo, nós adoptamos uma abordagem multi-layer do strain para analisar a deformação ventricular layer específica e observar os valores decrescentes de strain circunferencial e de gradiente transmural circunferencial subendocárdicao em sobreviventes a longo prazo expostos a antraciclina. Foi demonstrado em modelos animais de cardiotoxicidade de antraciclina que a miocitólise severa afeta principalmente o subendocárdio do ventrículo.20 Além disso, Perel et al.,21 observaram um padrão regional e difuso de aprimoramento subendocárdico usando ressonância magnética cardíaca em pacientes com cardiomiopatia induzida por antraciclina. Portanto, os achados em nosso estudo da redução dos valores de strain circunferencial subendocárdico e do gradiente circunferencial transmural, mas strain circunferencial subepicárdico preservado, foram consistentes com a mesma hipótese de lesão subendocárdica induzida por antraciclina. Além disso, verificou-se22 que, em pacientes com cardiomiopatia isquêmica crônica, o strain circunferencial subendocárdico era um poderoso preditor de eventos cardíacos e parecia ser um parâmetro melhor do que a FEVE e outras variáveis de strain analisadas por ecocardiografia. Portanto, acreditamos que talvez seja necessário dar mais importância às mudanças dos strains circunferenciais subendocárdicos. Observamos que após a exposição à antraciclina, os strains longitudinais de todas as três camadas diminuíram significativamente. No entanto, o gradiente de strain longitudinal transmural não apresentou diferença em relação ao grupo normal. É relatado que o subendocárdio é predominantemente composto de fibra miocárdica longitudinal. A deformação subendocárdica é maior na direção longitudinal e verifica o gradiente endo-epicárdico em ventrículos esquerdos normais na imagem por ressonância magnética.23,24 Assim, a mecânica ventricular esquerda longitudinal é predominantemente governada pela região subendocárdica do miocárdio, o que provavelmente explica os achados da redução de todas as três camadas de valores de strain longitudinal e a ausência de diferença no gradiente transmural longitudinal.

A falta de diferença no strain radial entre dois grupos em nosso estudo talvez não seja surpreendente, o que foi concordante com alguns estudos anteriores.25,26 Foi recentemente publicado que o strain radial pico diferiu amplamente em diferentes softwares e algoritmos, e pequenas mudanças de largura podem alterar grandes diferenças de RS.27 No presente estudo, a variação interobservador não mostrou reprodutibilidade satisfatória da medida de RS. Por isso, pode sugerir que os índices de deformação radial não são tão sensíveis quanto os strains circunferenciais e longitudinais na detecção de disfunção ventricular esquerda subclínica.

A ausência de associação entre os parâmetros de strain e a antraciclina acumulada apontou a falta de uma dose segura que não tenha cardiotoxicidade. Verificou-se que mesmo as crianças que receberam uma dose cumulativa de doxorrubicina tão baixa quanto 45mg/m2 tiveram redução da massa ventricular esquerda28 e o dano da antraciclina em todas as estruturas cardíacas pode começar com a primeira dose da mesma.29

Limitações

Várias limitações a este estudo merecem ser comentadas. Este foi um estudo transversal de uma coorte de pacientes relativamente pequena, que não forneceu informações sobre o valor dos parâmetros de deformação miocárdica no prognóstico. Serão necessários mais estudos avançados com metas clínicas profundas para determinar o significado clínico de nossos achados. Em segundo lugar, embora a ecocardiografia de speckle tracking permita a interrogação do strain global, esses parâmetros não são totalmente dependentes da carga e precisam ser interpretados com cautela quando se antecipa uma alteração do estado cardíaco com mudanças agudas na carga.

 Conclusão

Apesar da fração normal de ejeção do ventrículo esquerdo, anormalidades sutis na função sistólica do miocárdio estavam presentes em sobreviventes de longa duração após a exposição à antraciclina. Isso forneceu a evidência de comprometimento preferencial da deformação subendocárdica em sobreviventes de longa duração após exposição a antraciclina. A ecocardiografia multi-layer speckle tracking, uma ferramenta potencial não invasiva para a detecção de anormalidades miocárdicas induzidas por antraciclina subclínica, pode facilitar o seguimento longitudinal dessa coorte de pacientes em risco.

Fontes de financiamento

O presente estudo foi financiado pelo National Nature Science Foundation of China (81401411) e Nature Science Foundation of Shanghai (14ZR1425200, 16ZR1420600).

Vinculação acadêmica

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

Aprovação ética e consentimento informado

Este estudo foi aprovado pelo Comitê de Ética do Renji Hospital sob o número de protocolo 2014(N012). Todos os procedimentos envolvidos nesse estudo estão de acordo com a Declaração de Helsinki de 1975, atualizada em 2013. O consentimento informado foi obtido de todos os participantes incluídos no estudo.