Background: Long-term therapy with oral phosphodiesterase-5 inhibitors (PDE5I) is frequently implemented after left ventricular assist-device (LVAD) implantation to improve hemodynamics and prevent late-onset right ventricular failure or to facilitate listing for heart transplantation in individuals with persistent pulmonary hypertension. The safety and efficacy of this appoach has not been prospectively studied. Recent analyses of the Interagency Regstry for Mechanically Assisted Circulatory Support (INTERMACS) demonstrated improved survival for patients under long-term PDE5I after 48 months but higher incidence of early postoperative RV failure as well as a higher risk for gastrointestinal bleeding.The PIVAD study is an ongoing single-center study aiming to evaluate the role of PDE5I in patients on LVAD support after discontinuation of PDE5I. (NCT04117659).

Methods: In this prospective, single-arm, interventional study we enrolled LVAD recipients on oral PDE5I (sildenafil or tadalafil) after at least 1 month post-implant who were clinically stable on optimal medical therapy. The patients underwent physical examination, ECG, 6-minute walking test, cardiopulmonary exercise testing, transthoracic echocardiography, LVAD interrogation and laboratory testing at baseline and 4 weeks after discontinuation of oral PDE5I therapy.

Results: From 01/2020 to 10/2020 twenty-one patiens were included in the study. One patient experienced ischemic stroke before completing the follow-up assessment and 20 patients were included in the current analysis. Mean age was 52 years, 95% were male. Destination therapy was the primary treatment goal in 15% of this cohort while 85% received LVAD as a bridge to transplant. Mean dosis of tadalafil was 23.5 mg, of sildenafil 50mg. At follow-up no significant changes were elicited in echocardiographic markers of RV function, peak oxygen consumption, VE/VCO₂slope, eGFR, N-terminal pro-brain natriuretic peptide (NT-proBNP) concentration and average flow and power readings of the device but mild increase in walking distance (Table 1).

Conclusion: Discontinuation of PDE5I was not associated with deterioration of patients RV function and exercise capacity after 4 weeks. There is an ongoing need to evaluate the benefits and harms of PDE5I in the context of a randomized controlled trial.

Table 1.