Right Heart Failure While on Left Ventricular Assist Device Support Is Associated with Primary Graft Dysfunction.

Primary graft dysfunction (PGD) is a potentially devastating complication of heart transplantation. Understanding the risk factors for PGD in the modern era of heart transplantation is of vital importance. This study investigated the relationship between post-left ventricular assist device (LVAD) right heart failure (RHF) and transplant outcomes. Patients with durable, continuous-flow LVADs who were transplanted between 2010 and 2016 at Barnes-Jewish Hospital were included in the study. Data collection was performed through retrospective chart review. The primary outcome was the incidence of PGD stratified by pretransplant incidence of RHF while on LVAD support. Among the 141 patients included in the study, 41 developed RHF. In the RHF cohort, 18 patients developed PGD as compared to 14 patients in the group without RHF (44% vs. 14%; p < 0.001). Mortality was significantly higher in the RHF group at 30 days (20% vs. 1%; p < 0.001) and 1 year (22% vs. 6%; p = 0.013). In a multivariable logistic regression model adjusted for confounding variables, RHF was associated with a nearly fourfold increased risk of PGD (odds ratio, 3.91; p = 0.003). The results of this study show that patients supported with LVADs who develop early severe RHF or late RHF are at increased risk of PGD and death following cardiac transplantation.

Characterizing rapid-onset vasodilation to single muscle contractions in the human leg.

Rapid-onset vasodilation (ROV) following single muscle contractions has been examined in the forearm of humans, but has not yet been characterized in the leg. Given known vascular differences between the arm and leg, we sought to characterize ROV following single muscle contractions in the leg. Sixteen healthy men performed random ordered single contractions at 5, 10, 20, 40, and 60% of their maximum voluntary contraction (MVC) using isometric knee extension made with the leg above and below heart level, and these were compared with single isometric contractions of the forearm (handgrip). Single thigh cuff compressions (300 mmHg) were utilized to estimate the mechanical contribution to leg ROV. Continuous blood flow was determined by duplex-Doppler ultrasound and blood pressure via finger photoplethysmography (Finometer). Single isometric knee extensor contractions produced intensity-dependent increases in peak leg vascular conductance that were significantly greater than the forearm in both the above- and below-heart level positions (e.g., above heart level: leg 20% MVC, +138 ± 28% vs. arm 20% MVC, +89 ± 17%; P < 0.05). Thigh cuff compressions also produced a significant hyperemic response, but these were brief and smaller in magnitude compared with single isometric contractions in the leg. Collectively, these data demonstrate the presence of a rapid and robust vasodilation to single muscle contractions in the leg that is largely independent of mechanical factors, thus establishing the leg as a viable model to study ROV in humans.