Prognostic value of left ventricular apical tissue removed for HeartMate II left ventricular assist device placement

Background: With the increasing use of left ventricular assist devices, the left ventricular apical core has become a more frequently encountered surgical pathology tissue. We investigated the prognostic value of this cardiac tissue in short-term patient mortality. Previous studies have shown that the degree of cardiac fibrosis correlates with improvements in ejection fraction and the likelihood of weaning from an assist device. Methods: Left ventricular apical core tissues from 29 sequential subjects who received a HeartMate II continuous axial flow left ventricular assist device were studied retrospectively to determine whether interstitial fibrosis, replacement fibrosis (scar), the presence of mural thrombus, or other histopathologic findings were associated with hemodynamic changes or mortality in this population. Patients received left ventricular assist devices as bridges to transplantation or as destination therapy. Interstitial fibrosis was determined by observer scoring and digital scoring methods. Before and after left ventricular assist device procedure, right heart catheterizations were reviewed for clinical cardiac data. Results: The presence of replacement fibrosis in the apical core tissue significantly correlated with decreased improvement in pulmonary capillary wedge pressure after left ventricular assist device placement (P=.02). Ten subjects died over the course of this study. No specimen variables, including scar, interstitial fibrosis, and the presence of mural thrombosis, correlated with patient mortality. Conclusions: Pathologic findings in left ventricular apical cores have little prognostic utility in guiding patient management as related to overall 1-year mortality, but may indicate patients who are more likely to positively remodel their hearts.