Farhan Raza, Naga Dharmavaram MD, Timothy Hess, Ravi Dhingra, James Runo, Amy Chybowski, Callyn Kozitza, Supria Batra, Evelyn M. Horn, Naomi Chesler, Marlowe Eldridge
University of Wisconsin-Madison. Weill Cornell Medicine. University of California-Irvine.
United States
Clinical Cardiology
Clin Cardiol 2022; 45: 742-751
DOI: 10.1002/clc.23831
Abstract
Background: Among subjects with exercise intolerance and suspected early-stage pulmonary hypertension (PH), early identification of pulmonary vascular disease (PVD) with noninvasive methods is essential for prompt PH management
Hypothesis: Rest gas exchange parameters (minute ventilation to carbon dioxide production ratio: VE /VCO2 and end-tidal carbon dioxide: ETCO2 ) can identify PVD in early-stage PH.
Methods: We conducted a retrospective review of 55 subjects with early-stage PH (per echocardiogram), undergoing invasive exercise hemodynamics with cardiopulmonary exercise test to distinguish exercise intolerance mechanisms. Based on the rest and exercise hemodynamics, three distinct phenotypes were defined: (1) PVD, (2) pulmonary venous hypertension, and (3) noncardiac dyspnea (no rest or exercise PH). For all tests, *p < .05 was considered statistically significant.
Results: The mean age was 63.3 ± 13.4 years (53% female). In the overall cohort, higher rest VE /VCO2 and lower rest ETCO2 (mm Hg) correlated with high rest and exercise pulmonary vascular resistance (PVR) (r ~ 0.5-0.6*). On receiver-operating characteristic analysis to predict PVD (vs. non-PVD) subjects with noninvasive metrics, area under the curve for pulmonary artery systolic pressure (echocardiogram) = 0.53, rest VE /VCO2 = 0.70* and ETCO2 = 0.73*. Based on this, optimal thresholds of rest VE /VCO2 > 40 mm Hg and rest ETCO2 < 30 mm Hg were applied to the overall cohort. Subjects with both abnormal gas exchange parameters (n = 12, vs. both normal parameters, n = 19) had an exercise PVR 5.2 ± 2.6* (vs. 1.9 ± 1.2), mPAP/CO slope with exercise 10.2 ± 6.0* (vs. 2.9 ± 2.0), and none included subjects from the noncardiac dyspnea group.
Conclusions: In a broad cohort of subjects with suspected early-stage PH, referred for invasive exercise testing to distinguish mechanisms of exercise intolerance, rest gas exchange parameters (VE /VCO2 > 40 mm Hg and ETCO2 < 30 mm Hg) identify PVD.
Category
Pulmonary Hypertension Associated with Exercise
Diagnostic Testing for Pulmonary Vascular Disease. Non-invasive Testing
Diagnostic Testing for Pulmonary Vascular Disease. Invasive Testing
Age Focus: Adult Pulmonary Vascular Disease
Fresh or Filed Publication: Filed (PHiled). Greater than 1-2 years since publication
Article Access
Free PDF File or Full Text Article Available Through PubMed or DOI: Yes