Aims: Phosphodiesterase-5 inhibitors (PDE5I) are frequently implemented after left ventricular assist device (LVAD) implantation to improve haemodynamics in patients with early postoperative right ventricular (RV) failure. It is unknown if long-term PED5I therapy beyond the early post-operative period provides any clinical benefit in stable outpatients, who have recovered from post-operative RV failure under univentricular device support. This study aimed to investigate the impact of PDE5I discontinuation on RV function and cardiopulmonary exercise capacity in patients on durable LVAD support.

Methods and results: We enrolled 31 clinically stable LVAD recipients on long-term oral PDE5I therapy. The mean age was 53 years, and 90% were male. Patients discontinued PDE5I and underwent cardiopulmonary exercise testing, echocardiography, LVAD interrogation, and biomarker analysis at baseline and 4 weeks after PDE5I withdrawal. At 4 weeks, no significant changes were observed in echocardiographic indices of RV morphology and function but an increase in peak tricuspid regurgitation velocity (2.1 vs. 2.4 m/s, P = 0.01). Peak oxygen consumption (11.4 vs. 11.8 mL/min/kg, P = 0.52), minute ventilation/carbon dioxide production slope (33 vs. 35, P = 0.56), N-terminal pro-brain natriuretic peptide (1455 vs. 1399 pg/mL, P = 0.55), flow and power readings of the device, and quality of life (Kansas City Cardiomyopathy Questionnaire score 78.3% vs. 77.5%, P = 0.62) exhibited no significant changes. We observed an increase in 6-min walking distance (346 vs. 364 m, P = 0.03). Two patients were hospitalized for non-cardiac reasons (subtherapeutic INR, driveline infection). No patient was hospitalized for cardiac decompensation.

Conclusions: In LVAD patients with a history of early post-operative RV failure, discontinuation of long-term PDE5I therapy was not associated with deterioration of RV function, exercise capacity, and quality of life. PDE5I should be critically evaluated until more evidence regarding the net clinical benefit of this pharmacologic intervention becomes available.