Clinical insights into pulmonary hypertension in chronic obstructive pulmonary disease

Abstract

Pulmonary hypertension (PH) is a common complication of chronic obstructive pulmonary disease (COPD). Little is known about the prevalence and clinical profiles of patients with COPD-PH. We report the clinical characteristics, hemodynamic profiles, and prognosis in a large population of patients with COPD referred for right heart catheterization (RHC). We extracted data from all patients referred for RHC between 1997 and 2017 in Vanderbilt's deidentified medical record. PH was defined as mean pulmonary artery pressure >20 mmHg. Pre- and postcapillary PH were defined according to contemporary guidelines. COPD was identified using a validated rules-based algorithm requiring international classification of diseases codes relevant to COPD. We identified 6065 patients referred for RHC, of whom 1509 (24.9%) had COPD and 1213 had COPD and PH. Patients with COPD-PH had a higher prevalence of diabetes, atrial fibrillation, and heart failure compared with COPD without PH. Approximately 55% of patients with COPD-PH had elevated left ventricle (LV) filling pressure. Pulmonary function testing data from individuals with COPD-PH revealed subtype differences, with precapillary COPD-PH having lower diffusion capacity of the lungs for carbon monoxide (DLCO) values than the other COPD-PH subtypes. Patients with COPD-PH had significantly increased mortality compared with COPD alone (hazard ratio [HR]: 1.70, 95% confidence interval [CI]: 1.28-2.26) with the highest mortality among the combined pre- and postcapillary COPD-PH subgroup (HR: 2.39; 95% CI: 1.64-3.47). PH is common among patients with COPD referred for RHC. The etiology of PH in patients with COPD is often mixed due to multimorbidity and is associated with high mortality, which may have implications for risk factor management.

Keywords: COPD; hemodynamic phenotyping; survival outcomes.

Figure 1

Flow diagram for patient categorization. RHC, right heart catheterization; COPD, chronic obstructive pulmonary disease; PH, pulmonary hypertension; Cpc‐PH, combined postcapillary and precapillary pulmonary hypertension; Ipc‐PH, isolated postcapillary pulmonary hypertension; mPAP, mean pulmonary arterial pressure; Pc‐PH, precapillary pulmonary hypertension; U‐PH, undefined pulmonary hypertension; PAWP, pulmonary arterial wedge pressure; PVR, pulmonary vascular resistance

Figure 2

Forest plot of adjusted hazard ratio for mortality in COPD‐PH compared to COPD without PH. Mortality adjusted for the following variables determined within 6 months of right heart catheterization: age, sex, race. HR, hazard ratio; 95% CI, confidence interval. Cpc‐PH, combined postcapillary and precapillary pulmonary hypertension; Ipc‐PH, isolated postcapillary pulmonary hypertension; Pc‐PH, precapillary pulmonary hypertension; U‐PH, undefined pulmonary hypertension