Hemodynamic evidence of vascular remodeling in combined post- and precapillary pulmonary hypertension

PVRI Member Authors: Evan Brittain, John H. Newman, Anna Hemnes

Abstract

Although commonly encountered, patients with combined postcapillary and precapillary pulmonary hypertension (Cpc-PH) have poorly understood pulmonary vascular properties. The product of pulmonary vascular resistance and compliance, resistance-compliance (RC) time, is a measure of pulmonary vascular physiology. While RC time is lower in postcapillary PH than in precapillary PH, the RC time in Cpc-PH and the effect of pulmonary wedge pressure (PWP) on RC time are unknown. We tested the hypothesis that Cpc-PH has an RC time that resembles that in pulmonary arterial hypertension (PAH) more than that in isolated postcapillary PH (Ipc-PH). We analyzed the hemodynamics of 282 consecutive patients with PH referred for right heart catheterization (RHC) with a fluid challenge from 2004 to 2013 (cohort A) and 4,382 patients who underwent RHC between 1998 and 2014 for validation (cohort B). Baseline RC time in Cpc-PH was higher than that in Ipc-PH and lower than that in PAH in both cohorts (P < 0.001). In cohort A, RC time decreased after fluid challenge in patients with Ipc-PH but not in those with PAH or Cpc-PH (P < 0.001). In cohort B, the inverse relationship of pulmonary vascular compliance and resistance, as well as that of RC time and PWP, in Cpc-PH was similar to that in PAH and distinct from that in Ipc-PH. Our findings demonstrate that patients with Cpc-PH have pulmonary vascular physiology that resembles that of patients with PAH more than that of Ipc-PH patients. Further study is warranted to identify determinants of vascular remodeling and assess therapeutic response in this subset of PH.

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Topics

Catheterization
Pulmonary Arterial Hypertension

Authors

Tufik R. Assad, Evan L. Brittain, Quinn S. Wells, Eric H. Farber-Eger, Stephen J. Halliday, Laura N. Doss, Meng Xu, Li Wang, Frank E. Harrell, Chang Yu, Ivan M. Robbins, John H. Newman, Anna R. Hemnes

Published in:

Pulmonary Circulation Vol 6: No 3 cover image

September 2016

Pulmonary Circulation Vol 6: No 3

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