Pulmonary function assessment post‐left ventricular assist device implantation

AIM: The lungs—and particularly the alveolar‐capillary membrane—may be sensitive to continuous flow (CF) and pulmonary pressure alterations in heart failure (HF). We aimed to investigate long‐term effects of CF pumps on respiratory function. METHODS AND RESULTS: We conducted a retrospective study of patients with end‐stage HF at our institution. We analysed pulmonary function tests [e.g. forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV(1))] and diffusing capacity of the lung for carbon monoxide (D (LCO)) from before and after left ventricular assist device (LVAD) implantation and compared them with invasive haemodynamic studies. Of the 274 patients screened, final study analysis involved 44 patients with end‐stage HF who had CF LVAD implantation between 1 February 2007 and 31 December 2015 at our institution. These patients [mean (standard deviation, SD) age, 50 (9) years; male sex, n = 33, 75%] received either the HeartMate II (Thoratec Corp.) pump (77%) or the HeartWare (HeartWare International Inc.) pump. The mean (SD) left ventricular ejection fraction was 21% (13%). At a median of 237 days post‐LVAD implantation, we observed significant D (LCO) decrease (−23%) since pre‐implantation (P < 0.001). ΔD (LCO) had an inverse relationship with changes in pulmonary capillary wedge pressure (PCWP) and right atrial pressure (RAP) from pre‐LVAD to post‐LVAD implantation: ΔD (LCO) to ΔPCWP (r = 0.50, P < 0.01) and ΔD (LCO) to ΔRAP (r = 0.39, P < 0.05). We observed other reductions in FEV(1), FVC, and FEV(1)/FVC between pre‐LVAD and post‐LVAD implantation. In mean (SD) values, FEV(1) changed from 2.3 (0.7) to 2.1 (0.7) (P = 0.005); FVC decreased from 3.2 (0.8) to 2.9 (0.9) (P = 0.01); and FEV(1)/FVC went from 0.72 (0.1) to 0.72 (0.1) (P = 0.50). Landmark survival analysis revealed that ΔD (LCO) from 6 months after LVAD implantation was predictive of death for HF patients [hazard ratio (95% confidence interval), 0.60 (0.28–0.98); P = 0.03]. CONCLUSIONS: Pulmonary function did not improve after LVAD implantation. The degree of D (LCO) deterioration is related to haemodynamic status post‐LVAD implantation. The ΔD (LCO) within 6 months post‐operative was associated with survival.