Left ventricular relaxation is an independent predictor of the survival in hypertrophic cardiomyopathy
█ Original article
Vilmányi Gábor oh., Molnár Fanni oh., Tóth Levente, Simor Tamás, Faludi Réka
Pécsi Tudományegyetem, Klinikai Központ, Szívgyógyászati Klinika, Pécs
Background: Hypertrophic cardiomyopathy (HCM) is a genetically-determined disease with a high risk for sudden cardiac death or chronic heart failure. Our aim was to investigate the long term prognostic value of various echocardiographic and cardiac MRI parameters as well as N-terminal B-type natriuretic peptide (NT-proBNP) levels in HCM patients.
Patients and methods: 39 HCM patients (48±14 years) were enrolled into the study. They underwent echocardiography and cardiac MRI between 2003–2005. NT-proBNP levels were measured in parallel. Echocardiography was used to measure left ventricular outflow gradient and the parameters of the transmitral flow (E, A, DT, IVRT). Tissue Doppler technique was used to obtain systolic (s), early- (e’) and late-diastolic (a’) velocities on the lateral and septal mitral annulus. E/e’ ratio was calculated. Left atrial volumes (Vmax, Vmin, Vp) were measured by using 2D Simpson method. In addition to the left ventricular volumes and mass, left ventricular ejection fraction and maximal left ventricular wall thickness were measured by cardiac MRI. Left ventricular and atrial volumes as well as mass were normalized to body surface area. Survival was assessed after 12 years. Since in some cases the cause of death was unknown, all-cause mortality was chosen as outcome.
Results: During the follow-up period of 12.7±0.5 years, 14 patients (35.9%) died. By entering those variables (lateral e’, E/lateral e’, Vmin index, lnNT-proBNP) with p-values <0.1 in the univariate Cox regression analysis, multivariate Cox regression analysis was performed. Age was also included into the model. Lateral e’ was proved to be the only independent predictor of mortality: HR (95% CI): 0.702 (0.528–0.933); p=0.015. Using ROC analysis, lateral e’<7.7 cm/s was the strongest predictors of the mortality (sensitivity=76.9%, specificity =76.0%, AUC=0.768).
Conclusion: Lateral e’ – the parameter characterizing left ventricular relaxation – may be useful in the risk stratification and prognosis assessment in HCM patients.