Abstract 5855: Cardiac Fibrosis and Cellular Hypertrophy Predict the Degree of Reverse Remodeling and Improvement in Cardiac Function during Left Ventricular Assist System Support
[Background] There has been increasing reports of myocardial recovery after left ventricular assist system (LVAS) support. However, there still exists limited information as to in which patient population myocardial improvement is most likely to occur. The aim of this study was to investigate if the degree of cardiac fibrosis and myocyte size at the time of LVAS implantation predict the degree of reverse remodeling and improvement in cardiac function.
[Methods and Results] Thirty four patients who underwent LVAS-off test with echocardiography and right heart catheterization were studied. Mean age was 32.8 ± 17.8 years. Diagnosis was dilated cardiomyopathy in 20 patients, ischemic cardiomyopathy in 9, myocarditis in 2 and secondary cardiomyopathy in 3. The mean time from LVAS implantation to LVAS-off test was 234 ± 188 days. Left ventricular end-diastolic and end-systolic diameter (LVEDD and LVESD), left ventricular ejection fraction (LVEF), mean pulmonary artery pressure (mPAP), pulmonary capillary wedge pressure (PCWP) and cardiac index (CI) were measured during LVAS-off test and changes in these parameters from the baseline (before LVAS implantation) were calculated. Myocardial tissue was obtained form the apical core at LVAS implantation and degree of cardiac fibrosis and myocyte size was measured. Degree of cardiac fibrosis had significant negative correlations with decrease in LVEDD (r = −0.761, p < 0.0001), LVESD (r = −0.774, p < 0.0001), mPAP (r = −0.701, p = 0.0008) and PCWP (r =−0.598, p = 0.0169), and increase in LVEF (r = −0.629, p = 0.0004) and CI (r = −0.621, p = 0.0021). Myocyte size also had significant negative correlations with decrease in LVEDD (r = −0.451. p = 0.0197) and LVESV (r = −0.586, p = 0.0016), and increase in LVEF (r = −0.519. p = 0.0102). LVAS was successfully removed in 9 patients. Degree of cardiac fibrosis and myocyte size in these patients were significantly smaller than the other patients who did not undergo LVAS removal (10.3 ± 6.3 vs. 24.1 ± 3.4%, p = 0.0170 and 23.2 ± 6.1 vs. 30.4 ± 6.6 μm, p = 0.0105, respectively).
[Conclusions] Cardiac fibrosis and myocyte size at the time of LVAS implantation were significant predictors of degree of reverse remodeling and improvement in cardiac function with LVAS support.