The implications for cardiac recovery of left ventricular assist device support on myocardial collagen content

Background: To define the beneficial cellular changes that occur with chronic ventricular unloading, we determined the effect of left ventricular assist device (LVAD) placement on myocardial fibrosis. Methods: We obtained paired myocardial samples (before and after LVAD implantation) from 10 patients (aged 43 to 64 years) with end-stage cardiomyopathy. We first determined regional collagen expression of an explanted heart by a computerized semiquantitative analysis of positive picro-sirius red stained areas. Results: We found that there was no statistically significant difference in collagen content between regions of the failed heart studied. Next we determined collagen content in these paired myocardial biopsies pre- and post-LVAD implantation. All 10 patients had significant reductions in collagen content after LVAD placement with a mean reduction of 82% (percent of tissue area stained decreased from 32% ± 4% to 4% ± 0.8%, P < 0.001). Conclusion: In summary, these data demonstrate that chronic mechanical circulatory support significantly reduces fibrosis in the failing myocardium.