Characterization of Hemodynamics in Patients with Idiopathic and Thromboembolic Pulmonary Hypertension

Carmelle V Remillard,Jason X.-J Yuan

doi:10.4137/ccrpm.s696

Abstract

Demographic and hemodynamic data from patients with idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertension (CTEPH) have not been systematically characterized to identify differences related to gender, age, race, disease severity, and drug response. Our goal was to define the distribution and relation of IPAH and CTEPH based on these criteria. Hemodynamic and demographic data from 242 IPAH patients and 90 CTEPH patients were collected and compared. IPAH incidence was greater in women, but men had a higher basal mean pulmonary arterial pressure (mPAP). mPAP was comparable among all IPAH ethnic groups. IPAH patients with no history of fenfluramine-phentermine use had a higher mPAP than users. Exercise-induced IPAH was apparent in 14.5% of IPAH patients. Only 9% of IPAH patients responded to inhaled nitric oxide with a ≥20% decrease in mPAP. Compared to CTEPH patients, mPAP was greater but average age of diagnosis was lower in IPAH patients. mPAP negatively correlated with age of diagnosis in IPAH patients only. These results indicate that elevated CO is not the main determinant of mPAP in both IPAH and CTEPH patients. However, the two patient groups differ in terms of their demographic and hemodynamic distributions, and according to the correlation between mPAP and other clinical hemodynamics and demographics.

Highlights

Idiopathic pulmonary arterial hypertension (IPAH) is a rare vasculopathy involving small distal pulmonary arteries that may lead to right heart failure and death [51]
The objectives of this study were to analyze and characterize the clinical demographic and hemodynamic data obtained from IPAH and chronic thromboembolic pulmonary hypertension (CTEPH) patients in order to a) determine if the magnitude of mean pulmonary arterial pressure (PAP) elevation in IPAH patients is related to gender, age, race, fenfluramine use, and or vasoreactivity to inhaled nitric oxide (NO), and b) determine whether pulmonary hemodynamics and age at diagnosis are comparable between IPAH and CTEPH patients
Initial pathogenic mechanisms may be very different in patients with IPAH and CTEPH, the distributions of mean PAP, Cardiac output (CO), and pulmonary vascular resistance (PVR) in these two groups of patients appear to be similar

Summary

Introduction

Idiopathic pulmonary arterial hypertension (IPAH) is a rare vasculopathy involving small distal pulmonary arteries that may lead to right heart failure and death [51]. Up to 4% of patients with acute pulmonary embolism develop chronic thromboembolic pulmonary hypertension (CTEPH) [15, 35, 44], which accounts for 20,000–40,000 cases per year. An initial clot has been found in most cases of CTEPH, excessive pulmonary vascular remodeling in medium-sized and small arteries may occur and serve as a critical mechanism for the elevated PVR in these patients [5, 30, 52]. CTEPH is a vasculopathy involving coagulant occlusion of the large or central elastic proximal pulmonary arteries and thickening of proximal and distal arterial wall, rendering it accessible to surgical thromboendarterectomy

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