Left ventricular assist device or heart transplantation: impact of transpulmonary gradient and pulmonary vascular resistance on decision making

Abstract

Objectives: Fixed pulmonary hypertension is a contraindication for heart transplantation. Left ventricular assist device support may lower it and bridge patients to heart transplantation. The aim of the study was to investigate the optimal parameters for treatment decisions and the time course of their potential reversal to normal values during preoperative inotropic support.

Methods: Mean pulmonary arterial pressure, pulmonary vascular resistance and transpulmonary gradient were retrospectively analysed in 120 heart failure patients with severe pulmonary hypertension (mean age 51.7 ± 1.1 years, 93.3% males) treated between 2000 and 2009 with inotropes before left ventricular assist device implantation. The population was divided into three groups: patients with mean pulmonary arterial pressure > 25 mm Hg (group A, n = 113), patients with pulmonary vascular resistance > 2.5 Wood units (WU) (group B, n = 75) and patients with transpulmonary gradient > 12 mm Hg (group C, n = 55). Patients could be assigned to more than one group.

Results: After 24h of inotropic support, pulmonary vascular resistance decreased (4.1 ± 0.2 to 3 ± 0.1, -25%, p<0.001), as did the transpulmonary gradient (17 ± 0.5 to 14 ± 0.7, -18%, p < 0.001). There was no significant decrease of mean pulmonary arterial pressure. Fifty percent of patients presented transpulmonary gradient < 12 mmHg on the 3rd day and pulmonary vascular resistance < 2.5 WU on the 4th day. No further changes were observed in the following days. Left ventricular assist device support allowed 63 patients to be listed for heart transplantation and 40 received transplantation. A 30-day mortality after heart transplantation was higher in patients with fixed pulmonary hypertension, despite inotropes, than in those with reversible hypertension in groups B and C (12.5% and 11.1% vs 0%, respectively).

Conclusions: Transpulmonary gradient and pulmonary vascular resistance, but not mean pulmonary arterial pressure, are predictive parameters for successful heart transplantation in cases of severe postcapillary pulmonary hypertension. When no significant decrease in pulmonary vascular resistance and transpulmonary gradient after 3-4 days of pharmacological therapy is observed, mechanical circulatory support is the only option to bridge end-stage heart failure patients to heart transplantation. Survival after heart transplantation is strictly related to the reversibility of pulmonary vascular resistance and transpulmonary gradient before assist implantation, but not related to mean pulmonary artery pressure.