Abstract
PURPOSE: Patients with chronic heart failure (CHF) present with microcirculation alterations, partially attributed to endothelial dysfunction. Exercise training has been shown to induce beneficial effects in CHF patients. The aim of our study was to assess the effect of physical exercise on the microcirculation of CHF patients by near-infrared spectroscopy (NIRS).
METHODS: Sixteen consecutive stable CHF patients (men, n = 10; mean age = 50 +/- 12 years) participated in a 3-month rehabilitation program (3 sessions per week). All patients performed symptom-limited, ramp-incremental cardiopulmonary exercise testing on a cycle ergometer before and after the completion of the program. Measurements included peak oxygen uptake (VO2peak), VO2 at anaerobic threshold (AT), and first-degree slope of VO2 during the first minute of recovery (VO2/t slope). Tissue oxygen saturation was continuously measured by NIRS at the thenar muscle during a 3-minute vascular occlusion with a pneumatic cuff (occlusion technique) before and after the rehabilitation program.
RESULTS: The oxygen reperfusion rate (%/min) following the release of vascular occlusion increased significantly after the rehabilitation program (450 +/- 105 to 532 +/- 151, P = .004) as did vascular reactivity (from 27 +/- 13%/min to 39 +/- 21%/min, P = .006). In addition, there was a significant increase in VO2peak and AT (from 14.3 +/- 4.7 mL [middle dot] kg-1 [middle dot] min-1 to 16.7 +/- 6.3 mL [middle dot] kg-1 [middle dot] min-1 and from 9.5 +/- 3.6 mL [middle dot] kg-1 [middle dot] min-1 to 11.3 +/- 4 mL [middle dot] kg-1 [middle dot] min-1, P = .007 and P = .012, respectively) as well as in VO2/t slope (from 0.35 +/- 0.17 to 0.51 +/- 0.07 mL [middle dot] kg-1 [middle dot] min-1, P = .005).
CONCLUSIONS: Peripheral microcirculation of CHF patients measured by NIRS improved after the rehabilitation program. NIRS is a noninvasive technique that could be used to evaluate the effect of rehabilitation on the peripheral microcirculation of CHF patients.