The Effect of Left Ventricular Assist Devices (LVAD) on Pulmonary Hypertension in End-Stage Heart Failure.
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Despite the increasing prevalence of advanced heart failure, transplantation rates have remained stable in Canada due to limited organ availability. Consequently, the number of implanted left ventricular assist devices (LVAD) and average time on device support have both risen rapidly. End-stage heart failure is often complicated by pulmonary hypertension (PHTN). Patients with refractory PHTN have historically not been candidates for transplantation but reports of PHTN reversibility with LVAD support have led to changes to ISHLT listing criteria which now state that pulmonary hemodynamics should be reassessed 3 to 6 months following LVAD implantation for PHTN reversibility and transplantation candidacy. All patients having received a durable LVAD at two transplantation institutions were included in our study. Pre-operative characteristics were obtained from institutional databases. Right-heart catheterization data was retrospectively retrieved for 90 days pre-insertion and up to death or loss of follow-up. Pulmonary vascular resistance (PVR) was calculated for each instance from the transpulmonary gradient and cardiac output. Generalized estimating equations and logistic regression were used to determine if any variables were associated with PHTN reversibility. 177 patients for a total of 790 hemodynamic measurements were captured. Patients with pre-operative PHTN were less likely to have an ischemic etiology but were otherwise similar to the normotensive cohort. In most instances, longitudinal PVR measurements for patients with and without pre-operative PHTN normalized by 6 months post-operatively. Additionally, in those patients who went on to transplantation, the pulmonary hypertension reversal experienced while on device support persisted post-transplantation. Generalized estimating equation and logistic regression revealed that pre-operative PVR was the only clinical variable significantly associated with subsequent changes in PHTN. In this study, LVAD use led to reversibility of PHTN for the majority of patients within 6 months. With the exception of pre-operative PVR, no other clinical variable was significantly associated with PHTN reversibility.