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Doctoral Thesis
DOI
https://doi.org/10.11606/T.98.2020.tde-17122019-120121
Document
Author
Full name
Suzy Macêdo Fraulob
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2019
Supervisor
Committee
Assef, Jorge Eduardo (President)
Fischer, Cláudio Henrique
Cesar, Luiz Antonio Machado
Santos, Tiago Senra Garcia dos
Title in Portuguese
Avaliação da função miocárdica pelo strain 2D em coronariopatas: correlação com a ressonância magnética cardíaca
Keywords in Portuguese
Coração/diagnóstico por imagem
Coronariopatia
Ecocardiografia
Ressonância Magnética
Strain Bidimensional
Strain Pós-Sistólico
Abstract in Portuguese
INTRODUÇÃO: A identificação da viabilidade miocárdica em coronariopatas com disfunção do ventrículo esquerdo (VE) tem importantes implicações clínicas, uma vez que infartos transmurais não estão associados a um melhor prognóstico após a cirurgia de revascularização miocárdica (CRM). A ressonância magnética cardíaca (RMC) com gadolíneo é exame padrão-ouro para avaliação da viabilidade miocárdica por permitir a diferenciação de fibrose subendocárdica da transmural. O strain bidimensional (2D) pela ecocardiografia tem sido introduzido como uma nova técnica para avaliação da função do VE. Este estudo teve por objetivo comparar o strain sistólico (strain) e pós-sistólico (SPS) pela ecocardiografia em repouso com a massa de fibrose e sua transmuralidade pela RMC com gadolíneo antes da CRM e com a recuperação contrátil definida pela RMC após a CRM. MÉTODOS: 35 pacientes estáveis com disfunção sistólica isquêmica crônica do VE realizaram o strain 2D seguido pela RMC, com um total de 560 segmentos miocárdicos, de acordo com o modelo de 16 segmentos. O strain e SPS globais e segmentares foram obtidos nos planos longitudinal, circunferencial e radial e comparados com a massa de fibrose, sua transmuralidade (0 fibrose, 1-50% fibrose subendocárdica e 51-100% fibrose transmural) e com a recuperação contrátil. RESULTADOS: pacientes com média de 61,8 ± 7,5 anos, da fração de ejeção do VE de 38,9 ± 9,4% (RMC) e 17,5 ± 14,4 g de fibrose apresentaram strain longitudinal global (SLG) e índice pós-sistólico longitudinal global (IPSLG) de 10,34 ± 1,77% e 33,96 ± 12,0%, respectivamente. O IPSLG foi relacionado ao SLG (r = - 0,777, p < 0,001) e teve melhor correlação com a massa de fibrose (r = 0,560, p < 0,005). Pela análise de regressão multivariada, a massa de fibrose foi o único preditor para o IPSLG. Pela curva ROC, o IPSLG apresentou valor de corte de 29,51% para identificação de 5 g de fibrose com sensibilidade de 69,2%, especificidade de 66,7% e AUC de 0,756; um valor de corte de 34,98% identificou 30 g de fibrose com sensibilidade de 62,5%, especificidade de 70,4% e AUC de 0,810 (p < 0,005). Para nível segmentar, o strain longitudinal (SL) e tempo para o pico do SPS circunferencial (TSPSC) foram as variáveis que detectaram fibrose transmural, com valor de corte de 8,49% e 126 ms, sensibilidade de 70,2% e 64,6%, especificidade de 66,9% e 67,7% e AUC de 0,745 e 0,722, respectivamente; a integração entre SL e TSPSC mostrou uma AUC de 0,811. Em 12 meses após a CRM, o SL foi preditor de recuperação contrátil na regressão linear, enquanto o IPSL foi preditor na regressão logística múltipla (OR 1,130, IC de 95%, 1,074 - 1,188, p < 0,001). CONCLUSÕES: o IPSLG foi capaz de estimar a massa de fibrose; a integração entre SL e TSPSC foi mais acurada em identificar fibrose transmural e o SL e IPSL segmentares foram preditores para recuperação contrátil. Esta abordagem pelo strain 2D poderia ser integrada no manejo clínico do coronariopata antes da CRM, com a finalidade de identificar segmentos miocárdicos com potencial de recuperação funcional.
Title in English
Evaluation of myocardial function by 2D strain in patients with coronary artery disease: correlation with cardiac magnetic resonance
Keywords in English
Coronary artery disease
Echocardiography
Heart/imaging diagnosis
Magnetic resonance
Post-systolic strain
Two-dimensional strain
Abstract in English
INTRODUCTION: The identification of myocardial viability in patients with coronary artery disease (CAD) and depressed left ventricular function has important clinical implications, because transmural infarcts are not associated with better prognosis after revascularization. Contrast enhancement on magnetic resonance imaging (ceMRI) provides information about scar mass and scar transmurality. It has been considered the gold standard for myocardial viability evaluation by allowing to differentiate nontransmural infarction from transmural infarction. Two-dimensional speckle tracking echocardiography (STE) has been introduced as a new technique to evaluate left ventricle (LV) function. This study aimed to compare systolic (strain) and post-systolic myocardial deformation by resting STE with scar mass and scar transmurality by ceMRI (both before revascularization) and with contractile recovery by ceMRI at 12-months after revascularization. METHODS: Data were available from 35 stable patients with chronic ischemic LV dysfunction, that underwent resting STE followed by ceMRI, with a total 560 myocardial segments by 16-segment model. Global and segmental values of strain and post-systolic strain in the longitudinal, circumferential, and radial directions were compared with scar mass, infarct transmurality stratified by ceMRI (no scar, 0%; nontransmural scar, late hyperenhancement 1-50%; and transmural, late hyperenhancement 51-100%) and contractile recovery. RESULTS: patients with mean age of 61.8 ± 7.5 years, LV ejection fraction of 38.9 ± 9.4% and 17.5 ± 14.4 g scar mass assessed by ceMRI presented global longitudinal strain (GLS) and global longitudinal post-systolic index (GLPSI) of 10.34 ± 1.77% and 33.96 ± 12.0%, respectively. GLPSI was significantly correlated to GLS (r = - 0.777, p < 0.001). GLPSI showed best correlation with scar mass (r = 0.560, p < 0.005). By multivariate regression analysis, scar mass was the only significant predictor of GLPSI. By ROC analysis for GLPSI, a cut-off value of 29.51% identified 5 g scar with sensitivity of 69.2%, specificity of 66.7%, and AUC of 0.756; a cut-off value of 34.98% identified 30 g scar, with sensitivity of 62.5%, specificity of 70.4% and AUC of 0.810 (p < 0.005). For segmental level, longitudinal strain (LS) and circumferential post systolic time (CPST) were only significant parameters to detect transmural infarction; a cut-off of LS and CPST of 8.49% and 126 ms, had a sensitivity of 70.2% and 64.6%, specificity of 66.9% and 67.7% and AUC of 0.745 and 0.722, respectively; integration between LS and CPST showed an AUC of 0.811. At 12-months follow-up after revascularization, linear regression analysis pointed out that segmental LS was a predictor for contractile recovery, while logistic regression analysis presented LPSI as a predictor (odds ratio 1.130; 95% confidence interval, 1.074 to 1.188, p < 0.001). CONCLUSIONS: The GLPSI was able to assess the global mass scar; the integration between LS and CPST appeared to be more accurate in identifying transmural infarct and LS and LPSI were predictors for contractile recovery after revascularization. This STE approach might be integrated into clinical management before revascularization, for identifying of myocardial segments with potential for functional recovery.
 
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Publishing Date
2020-03-04
 
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