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Diastolic Dysfunction of the Cardiac Allograft and Maximal Exercise Capacity

2009; Elsevier BV; Volume: 28; Issue: 5 Linguagem: Inglês

10.1016/j.healun.2008.12.001

1557-3117

Laurent Roten, J. Schmid, Franziska Merz, Thierry Carrel, Marcel Zwahlen, Nazan Walpoth, Paul Mohaçsi, Roger Hullin,

Mechanical Circulatory Support Devices

Background Peak oxygen uptake (peak Vo2) is an established integrative measurement of maximal exercise capacity in cardiovascular disease. After heart transplantation (HTx) peak Vo2 remains reduced despite normal systolic left ventricular function, which highlights the relevance of diastolic function. In this study we aim to characterize the predictive significance of cardiac allograft diastolic function for peak Vo2. Methods Peak Vo2 was measured using a ramp protocol on a bicycle ergometer. Left ventricular (LV) diastolic function was assessed with tissue Doppler imaging sizing the velocity of the early (Ea) and late (Aa) apical movement of the mitral annulus, and conventional Doppler measuring early (E) and late (A) diastolic transmitral flow propagation. Correlation coefficients were calculated and linear regression models fitted. Results The post-transplant time interval of the 39 HTxs ranged from 0.4 to 20.1 years. The mean age of the recipients was 55 ± 14 years and body mass index (BMI) was 25.4 ± 3.9 kg/m2. Mean LV ejection fraction was 62 ± 4%, mean LV mass index 108 ± 22 g/m2 and mean peak Vo2 20.1 ± 6.3 ml/kg/min. Peak Vo2 was reduced in patients with more severe diastolic dysfunction (pseudonormal or restrictive transmitral inflow pattern), or when E/Ea was ≥10. Peak Vo2 correlated with recipient age (r = −0.643, p < 0.001), peak heart rate (r = 0.616, p < 0.001) and BMI (r = −0.417, p = 0.008). Of all echocardiographic measurements, Ea (r = 0.561, p < 0.001) and Ea/Aa (r = 0.495, p = 0.002) correlated best. Multivariate analysis identified age, heart rate, BMI and Ea/Aa as independent predictors of peak Vo2. Conclusions Diastolic dysfunction is relevant for the limitation of maximal exercise capacity after HTx. Peak oxygen uptake (peak Vo2) is an established integrative measurement of maximal exercise capacity in cardiovascular disease. After heart transplantation (HTx) peak Vo2 remains reduced despite normal systolic left ventricular function, which highlights the relevance of diastolic function. In this study we aim to characterize the predictive significance of cardiac allograft diastolic function for peak Vo2. Peak Vo2 was measured using a ramp protocol on a bicycle ergometer. Left ventricular (LV) diastolic function was assessed with tissue Doppler imaging sizing the velocity of the early (Ea) and late (Aa) apical movement of the mitral annulus, and conventional Doppler measuring early (E) and late (A) diastolic transmitral flow propagation. Correlation coefficients were calculated and linear regression models fitted. The post-transplant time interval of the 39 HTxs ranged from 0.4 to 20.1 years. The mean age of the recipients was 55 ± 14 years and body mass index (BMI) was 25.4 ± 3.9 kg/m2. Mean LV ejection fraction was 62 ± 4%, mean LV mass index 108 ± 22 g/m2 and mean peak Vo2 20.1 ± 6.3 ml/kg/min. Peak Vo2 was reduced in patients with more severe diastolic dysfunction (pseudonormal or restrictive transmitral inflow pattern), or when E/Ea was ≥10. Peak Vo2 correlated with recipient age (r = −0.643, p < 0.001), peak heart rate (r = 0.616, p < 0.001) and BMI (r = −0.417, p = 0.008). Of all echocardiographic measurements, Ea (r = 0.561, p < 0.001) and Ea/Aa (r = 0.495, p = 0.002) correlated best. Multivariate analysis identified age, heart rate, BMI and Ea/Aa as independent predictors of peak Vo2. Diastolic dysfunction is relevant for the limitation of maximal exercise capacity after HTx.