Abstract 2195: Significant Relation of Arterial Stiffening to Hyperventilatory Response to Exercise in Patients with Coronary Artery Disease

Abstract

Exercise intolerance is a common feature of patients with coronary artery disease (CAD). Enhanced ventilatory response is determinants of exercise capacity and marker of a poor prognosis irrespective of LV systolic function. Pulse wave velocity (PWV), which is a reliable marker of arterial stiffness, modulates left ventricular (LV) function and is related to exercise capacity in CAD patients; however, the relationship of PWV to ventilatory response to exercise in CAD patients has not been fully elucidated. In this study, we examined PWV and cardiopulmonary exercise testing (CPX) in CAD patients and evaluated the relationship between PWV and ventilatory response to exercise. We studied 81 CAD patients (69±8yo, 64men). All subjects underwent symptom limited CPX. Ventilatory response to exercise was determined by VE/VCO 2 slope. We also measured PWV using an automated device (form ABI/PWV, Colin, Japan) prior to CPX. LV function was assessed by echocardiogram. In univariate analysis, PWV was related to VE/VCO 2 slope (r=0.34, p<0.01). PWV was also associated with exercise time (r=−0.22, p<0.05), time to ST depression (r=−0.32, p<0.01) and peak VO 2 (r=−0.44, p<0.01). The relationship between PWV and VE/VCO 2 was still significant after adjustment for age, sex and blood pressure. Patients with high PWV (over 1800cm/sec, n=29) had higher BNP (140±214 vs 59±66 pg/ml, p<0.05) and lower E/A ratio (0.7±0.2 vs. 0.9±0.3, p<0.05) than those with low PWV (under 1800cm/sec, n=52). In exercise testing, patients with high PWV had higher VE/VCO 2 slope (30.9±2.6 vs. 29.0±3.4, p<0.01), shorter time to ST depression than patients with low PWV (352±79 vs. 403±59 sec, p<0.01), whereas severity of CAD, defined as number of diseased vessels, was comparable between the two groups. Arterial stiffening is associated with enhanced ventilatory response to exercise in CAD patients. Diastolic dysfunction and lowered threshold of myocardial ischemia associated with arterial stiffening are probably involved in the hyperventilatory response to exercise in CAD patients.