Higashi A, Dohi Y, Yamabe S, Kinoshita H, Sada Y, Kitagawa T,
Hidaka T, Kurisu S, Yamamoto H, Yasunobu Y, Kihara Y

Heart Vessels. 2017 Nov;32(11):1350-1357. doi: 10.1007/s00380-017-0999-y. Epub
2017 May 30.

Cardiopulmonary exercise testing (CPET) is useful for the evaluation of patients
with suspected or confirmed pulmonary hypertension (PH). End-tidal carbon dioxide
pressure (PETCO2) 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
PETCO2 at the anaerobic threshold (AT) and mPAP (r = -0.66; P < 0.01). Multiple
regression analysis showed that PETCO2 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 PETCO2 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 PETCO2 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.