Oxygen consumption and carbon-dioxide recovery kinetics in the prediction of coronary artery disease severity and outcome

Background: Revascularization appears to be beneficial only in patients with high levels of ischemia. This study examined the utility of gas analysis during the recovery phase of cardiopulmonary exercise testing (CPET) in predicting coronary artery disease (CAD) severity and prognosis. Methods: 40 Caucasian patients (21.2% females), mean age 63.5 +/- 7.6 with significant coronary artery lesions (>= 50%) were studied. Within two months of coronary angiography, CPET on a treadmill (TM) and recumbent ergometer (RE) were performed on two visits 2-4 days apart; subjects were subsequently followed 32 +/- 10 months. Myocardial wall motion was recorded by echocardiography at rest and peak exercise. Ischemia was quantified by the wall motion score index (WMSI). Results: Mean ejection fraction was 56.7 +/- 9.6%. Patients with 1-2 stenotic coronary arteries (SCA) showed a poorer CPET response during the recovery phase than patients with 3-SCA. ROC analysis revealed the change of carbon-dioxide output (Delta VCO2) recovery/peak (area under ROC curve 0.77, p = 0.02, Sn = 87.5%, Sp = 70.4%) and oxygen uptake (Delta VO2) recovery/peak during TM CPET (area under ROC curve 0.76, p = 0.03, Sn 75.0%, Sp 77.8%) were significant in distinguishing between 1-2-SCA and 3-SCA. The same variables predicted.WMSI peak/rest on univariate analysis (p < 0.05). Multivariate Cox analysis revealed a high predictive value of Delta VO2 recovery/peak obtained during TM CPET for composite endpoint of cumulative cardiac events (HR = 1.27, CI = 1.07-1.51, p = 0.008). Conclusions: The current study suggests CPET parameters in recovery hold predictive value for CAD severity and prognosis. TM testing seems to be a better approach in the assessment of CAD severity and prognosis. (C) 2017 Elsevier B.V. All rights reserved.