Lung diffusion capacity correlates with pre-implant pulmonary hypertension and predicts outcome after LVAD...

Diffusing capacity of the lung for carbon monoxide (DL_CO ) reduction is common in heart failure (HF) and is associated with a worse prognosis. Correlations between DL_CO and pulmonary hypertension (PH) are unclear, and published data are conflicting; it has been shown that DL_CO impairment may persist or even worsen after normalization of pulmonary pressures following left ventricle assist device (LVAD) implantation, maybe reflecting persistent pulmonary damage. We aimed to investigate the impact of pre-implant DL_CO and central haemodynamics on outcome in patients with advanced HF implanted with a LVAD.

We retrospectively analysed pre-implant and post-implant data from 42 patients implanted with a LVAD at our institution. Out of 42 patients, 35 had post-capillary PH before implantation, including 17 with combined post- and pre-capillary PH (Cpc-PH). Median DL_CO was 59% (IQR 47-68%), and it inversely correlated with pulmonary vascular resistance (PVR) (P 0.037) and diastolic pulmonary gradient (DPG) (P 0.042). Compared with baseline, LVAD resulted in improvement in LV diameter (LVDd, P < 0.001), mitral regurgitation (P 0.022), and PH (mPAP 24 vs. 36 mmHg, P < 0.001; PAWP 12 vs. 23 mmHg, P 0.001; pulmonary artery compliance, C_PA 3.1 vs. 1.9 mL/mmHg, P 0.021). Lower DL_CO and Cpc-PH at baseline were associated with a better LV reverse remodelling post-implantation (P 0.027 for LVDd) but also with a smaller gain in C_PA (P 0.049).

Before LVAD implantation, DL_CO impairment is associated with higher PVR and DPG, suggesting that it might be an expression of persistent pulmonary damage occurring in Cpc-PH. After LVAD implantation, both LV dimension and haemodynamics improve. Lower pre-implant DL_CO is associated with better LV reverse remodelling.