OBJECTIVETo explore the role of peak oxygen consumption in assessment of heart function of patients with pulmonary hypertension.

METHODSFrom September 2010 to April 2012, 101 patients [29 male, mean age: (32.6 ± 11.4 )years] with pulmonary hypertension diagnosis by right heart catheterization were enrolled. Correlations among peak oxygen consumption, New York Heart Association (NYHA) class, NT-proBNP, 6 minute walking distance (6MWD) and cardiac index are analyzed.

RESULTSThere were 44 cases with NYHA class II (43.6%), 49 cases with NYHA class III (48.5%), mean 6MWD was (421 ± 91 )m, NT-proBNP was (1262 ± 816) ng/L, pulmonary vascular resistance was (1031 ± 582) dyn·s(-1)·cm(-5), CI was (3.5 ± 2.3) L·min(-1)·m(-2), peak oxygen consumption was( 13.8 ± 4.1)ml·min(-1)·kg(-1). 6MWD, pulmonary vascular resistance and peak oxygen consumption were related to CI (r = 0.299, -0.541, 0.341, respectively, all P < 0.05), but NYHA class and NT-proBNP were not correlated to CI. Multiple regression analysis demonstrated that peak oxygen consumption (B = 0.135, P = 0.004) but not 6MWD was correlated with CI after adjusting age, sex and pulmonary vascular resistance. ROC analysis found that the sensitivity and specificity using peak oxygen consumption <15.2 ml·min(-1)·kg(-1) as a cut-off value was 92.6% and 57.5%, respectively, for diagnosing severe heart dysfunction.

CONCLUSIONSThe correlation between peak oxygen consumption and CI is better than that of NYHA class, 6MWD, and NT-proBNP with CI. Peak oxygen consumption less than 15.2 ml·min(-1)·kg(-1) could be used to detect reduced CI in patients with pulmonary hypertension.