Cardiopulmonary exercise testing improves diagnostic specificity in patients with echocardiography-suspected pulmonary hypertension.

Abstract

Doppler echocardiography is usually the first diagnostic investigation for patients suspected with pulmonary hypertension (PH), but it is often inaccurate when used alone, especially in mild PH. Cardiopulmonary exercise testing (CPET) may serve as a complementary tool to improve diagnostic accuracy in echocardiography-suspected "PH possible" patients. Eighty-eight consecutive patients with suspected PH (referred to as "PH possible" hereafter) based on echocardiography were included in the study. CPET was assessed subsequently and PH was confirmed by right-heart catheterization in all subjects. We analyzed CPET data from patients and derived a CPET prediction rule to hemodynamically differentiate PH. Eighty-eight patients (27 patients with confirmed PH, and PH ruled out in 61 patients) were included in the study. Compared with non-PH patients, the PH subjects had lower peak oxygen uptake (VO2 ), aerobic capacity (AT), peak partial pressure of end-tidal CO2 (PET CO2 ), oxygen uptake efficiency plateau (OUEP), and oxygen uptake efficiency slope (OUES), along with higher minute ventilation (VE)/carbon dioxide output (VCO2 ) slope and lowest VE/VCO2 (P < 0.001). VE/VCO2 slope and AT were independent predictors of PH derived from multivariate logistic regression adjusted for age and body mass index. A score combining VE/VCO2 slope and AT reached a high area under the curve value of 0.98. A score ≥0.5 had 95% specificity and 92.6% sensitivity for diagnosis of PH. A score combining VE/VCO2 slope and AT provides high specificity in screening out PH from a pool of echocardiography-suspected PH patients.