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 (FEV1)] 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). Delta D-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: Delta D-LCO to Delta PCWP (r = 0.50, P < 0.01) and Delta D-LCO to Delta RAP (r = 0.39, P < 0.05). We observed other reductions in FEV1, FVC, and FEV1/FVC between pre-LVAD and post-LVAD implantation. In mean (SD) values, FEV1 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 FEV1/FVC went from 0.72 (0.1) to 0.72 (0.1) (P = 0.50). Landmark survival analysis revealed that Delta D-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 Delta D-LCO within 6 months post-operative was associated with survival.