Arterial Stiffness Index and Exercise Tolerance in Patients Undergoing Cardiac Rehabilitation

Arterial stiffness contributes to the development of cardiovascular disease (CVD). However, the relationship between the arterial stiffness and exercise tolerance in CVD patients with preserved ejection fraction (pEF) and those with reduced EF (rEF) is unclear. We enrolled 358 patients who participated in cardiac rehabilitation and underwent cardiopulmonary exercise testing at Juntendo University Hospital. After excluding 195 patients who had undergone open heart surgery and 20 patients with mid-range EF, the patients were divided into pEF (n = 99) and rEF (n = 44) groups. Arterial stiffness was assessed using arterial velocity pulse index (AVI) and arterial pressure volume index (API) at rest. The patients in the pEF group were significantly older and had a higher prevalence of coronary artery disease than the rEF group. The pEF group had significantly lower AVI levels and higher API levels than the rEF group. In the pEF group, the peak oxygen uptake (peak VO₂) and the anaerobic threshold was significantly higher than those in the rEF group. The peak VO₂ was significantly and negatively correlated with AVI and API in the pEF group (All, P < 0.05), but not in the rEF group. Multivariate linear regression analyses demonstrated that AVI was independently associated with peak VO₂ (β = -0.34, P < 0.05) in the pEF group. In conclusion, AVI may be a useful factor for assessing exercise tolerance, particularly in CVD patients with pEF.