Evaluation of end-tidal CO2 pressure at the anaerobic threshold for detecting and assessing pulmonary hypertension

Abstract

Cardiopulmonary exercise testing (CPET) is useful for the evaluation of patients with suspected or confirmed pulmonary hypertension (PH). End-tidal carbon dioxide pressure (PETCO) during exercise is reduced with elevated pulmonary artery pressure. However, the utility of ventilatory parameters such as CPET for detecting PH remains unclear. We conducted a review in 155 patients who underwent right heart catheterization and CPET. Fifty-nine patients had PH [mean pulmonary arterial pressure (mPAP) ≥25 mmHg]. There was an inverse correlation between PETCO at the anaerobic threshold (AT) and mPAP (r = -0.66; P < 0.01). Multiple regression analysis showed that PETCO at the AT was independently associated with an elevated mPAP (P = 0.04). The sensitivity and specificity of CPET for PH were 80 and 86%, respectively, when the cut-off value identified by receiver operating characteristic curve analysis for PETCO at the AT was ≤34.7 mmHg. A combination of echocardiography and CPET improved the sensitivity in detecting PH without markedly reducing specificity (sensitivity 87%, specificity 85%). Evaluation of PETCO at the AT is useful for estimating pulmonary pressure. A combination of CPET and previous screening algorithms for PH may enhance the diagnostic ability of PH.

Screening for pulmonary arterial hypertension in adults carrying a BMPR2 mutation

“…Since no CPET value alone are conclusive of PAH, we used a predefined probability score of PH on CPET adapted from previous published studies. [15][16][17][18][19][20] Refinements and validation of CPET scores suggestive of PH should be encouraged in future studies evaluating early diagnosis of PAH. It is therefore likely that the current recommendation of annual echocardiography on its own will be outperformed by a comprehensive multimodal approach in asymptomatic BMPR2 mutation carriers.…”

“…An investigational CPET probability score of PH was predefined based on five criteria adapted from data published by our group and others (Supplemental Table 1). [15][16][17][18][19][20] Complete methodological descriptions of all investigations are presented in Supplementary Methods.…”