Aortic blood pressure and pulse wave indices responses to exercise in peripheral artery disease

Abstract

Peripheral artery disease (PAD) refers to obstructed blood flow in peripheral arteries typically due to atherosclerotic plaques. How PAD alters aortic blood pressure and pressure wave propagation during exercise is unclear. Thus, this study examined central blood pressure responses to plantar flexion exercise by investigating aortic pulse wave properties in PAD. Thirteen subjects with PAD and 13 healthy [age-, sex-, body mass index (BMI) matched] subjects performed rhythmic plantar flexion for 14 min or until fatigue (20 contractions/min; started at 2 kg with 1 kg/min increment up to 12 kg). Brachial (oscillometric cuff) and radial (SphygmoCor) blood pressure and derived-aortic waveforms were analyzed during supine rest and plantar flexion exercise. At rest, baseline augmentation index ( P = 0.0263) and cardiac wasted energy ( P = 0.0321) were greater in PAD due to earlier arrival of the reflected wave ( P = 0.0289). During exercise, aortic blood pressure (aMAP) and aortic pulse pressure showed significant interaction effects ( P = 0.0041 and P = 0.0109, respectively). In particular, PAD had a greater aMAP increase at peak exercise ( P = 0.0147). Moreover, the tension time index was greater during exercise in PAD ( P = 0.0173), especially at peak exercise ( P = 0.0173), whereas the diastolic time index ( P = 0.0685) was not different between the two groups. Hence, during exercise, the subendocardial viability ratio was lower in PAD ( P = 0.0164), especially at peak exercise ( P = 0.0164). The results suggest that in PAD, the aortic blood pressure responses and myocardial oxygen demand during exercise are increased compared with healthy controls.