Acute impairment of the endothelial function by maximal treadmill exercise in patients with intermittent claudication, and its improvement after supervised physical training

Abstract

Aim: The aim of this study was to determine the effects of maximal exercise and of physical training on endothelial function (EF) of patients with intermittent claudication (IC).

Methods: EF, assessed by ultrasonography of the brachial artery, has been measured in 22 male patients with IC before (pre-exercise EF) and after (postexercise EF) maximal treadmill test. Absolute claudication distance (ACD) and ankle brachial index (ABI) have been measured too. The measurements have been repeated after 18 days (3 times weekly, for 6 weeks) of supervised physical training.

Results: Before training, the pre-exercise EF was 7.6+/-2.94 and postexercise EF 5.28+/-3.3 (-33.2%) (P<0.01). After training, the pre-exercise EF was 10.3+/-4.04, whilst postexercise EF was 7.79+/-2.56 (-18.97%) (P<0.01). The differences between the pre-exercise value before and after training and between the postexercise value before and after training were significant (P<0.01). ACD and ABI after training increased respectively from 93.95 to 166.55 m and from 0.67 to 0.71 (P<0.001).

Conclusions: Endothelial dysfunction takes a relevant part in the pathophysiology of IC, with 2/3 of the patients showing an EF lower than the pathological cut-off. Maximal exercise worsens the EF, according to the trend associated with the acute inflammatory response. All these features suggest that physical activity in IC should not utilize the maximal working load, in order to avoid the high inflammatory activation and the acute complications of atherosclerotic plaque. The supervised physical training, besides confirming itself as the most effective means to increase the walking ability, also proved to be able to improve the EF of these patients, as described about other diseases. It is probable that moderate hemodynamic stress reduces the levels of the inflammatory markers and increases the flow-mediated vasodilation through an ischemic preconditioning. The increased walking ability, associated with the improvement of EF could improve the heavy systemic outcome of claudicant patients, as it has been demonstrated in patients with coronary heart disease. Further prospective survival studies on cardiovascular outcomes of trained claudicant patients are needed.