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[This corrects the article DOI: 10.1371/journal.pone.0188383.].

Exercise ventilation/perfusion matching in continuous-flow left ventricular assist device recipients (LVAD) has not been studied systematically. Twenty-five LVAD and two groups of 15 reduced ejection fraction chronic heart failure (HFrEF) patients with peak VO2 matched to that of LVAD (HFrEF-matched) and ≥14 ml/kg/min (HFrEF≥14), respectively, underwent cardiopulmonary exercise testing with arterial blood gas analysis, echocardiogram and venous blood sampling for renal function evaluation. Arterial-end-tidal PCO2 difference (P(a-ET)CO2) and physiological dead space-tidal volume ratio (VD/VT) were used as descriptors of alveolar and total wasted ventilation, respectively. Tricuspid annular plane systolic excursion/pulmonary artery systolic pressure ratio (TAPSE/PASP) and blood urea nitrogen/creatinine ratio were calculated in all patients and used as surrogates of right ventriculo-arterial coupling and circulating effective volume, respectively. LVAD and HFrEF-matched showed no rest-to-peak change of P(a-ET)CO2 (4.5±2.4 vs. 4.3±2.2 mm Hg and 4.1±1.4 vs. 3.8±2.5 mm Hg, respectively, both p >0.40), whereas a decrease was observed in HFrEF≥14 (6.5±3.6 vs. 2.8±2.0 mm Hg, p <0.0001). Rest-to-peak changes of P(a-ET)CO2 correlated to those of VD/VT (r = 0.70, p <0.0001). Multiple regression indicated TAPSE/PASP and blood urea nitrogen/creatinine ratio as independent predictors of peak P(a-ET)CO2. LVAD exercise gas exchange is characterized by alveolar wasted ventilation, i.e. hypoperfusion of ventilated alveoli, similar to that of advanced HFrEF patients and related to surrogates of right ventriculo-arterial coupling and circulating effective volume., Competing Interests: The authors have declared that no competing interests exist.

Background: The hemodynamic definitions of pulmonary hypertension (PH) in left heart disease have recently been refined to better match the characteristics required to reflect the presence of pulmonary vascular disease. Accordingly, we tested the hypothesis that abnormalities in the stiffness of pulmonary circulation would persist after heart transplantation in patients with combined post-capillary and pre-capillary PH (Cpc-PH) in contrast to those with isolated post-capillary PH (Ipc-PH)., Methods: We retrospectively analyzed right heart hemodynamics in a cohort of 295 consecutive patients with heart failure and advanced left ventricular systolic dysfunction (LVSD) before and 1 year after heart transplantation., Results: According to their baseline hemodynamic profile, patients were classified as: 75 Cpc-PH, 111 Ipc-PH, and 98 without PH (no-PH), and 11 pre-capillary PH. One year after heart transplantation, pulmonary artery pressures, pulmonary vascular resistance and cardiac index normalized in all patients regardless of the baseline hemodynamic profile. However, pulmonary arterial compliance remained lower in Cpc-PH patients (from 1.6±1.2 at baseline to 3.7±1.4 ml/mmHg at 1 year) than in Ipc-PH (from 1.2±2.0 to 4.4±2.3 ml/mmHg) and no-PH patients (from 3.7±2.0 to 4.5±1.8 ml/mmHg); (adjusted p = 0.03 Ipc-PH vs. Cpc-PH INT<0.001)., Conclusions: In heart failure patients with advanced LVSD, a hemodynamic profile characterized by Cpc-PH predicts the persistence of a stiffer pulmonary circulation at 1 year after heart transplantation.