Acute Cardiopulmonary And Hemodynamic Responses To Exercise With Blood-flow Restriction In Heart Failure Patients

Abstract

Muscle training with blood flow restriction (BFR) can induce significant increases in muscle strength and mass, while BFR during low intensity aerobic training increases aerobic capacity more than the usual aerobic exercise at the same intensity. However, little is known about the safety and feasibility of BFR training in patients with chronic heart failure (CHF). PURPOSE: This study compared hemodynamic and cardiopulmonary responses during low intensity aerobic exercise with and without BFR in CHF patients. METHODS: Nine CHF patients, 7 males and 2 females (age: 55.6±12.2 years, height: 175.0±10.3 cm, body mass: 89.6±29.1 kg, VO2peak: 22.4±5.04 ml/kg/min, ejection fraction: 36±6%, NYHA: I-II) volunteered to participate in this crossover study. Each participant performed the same aerobic exercise protocol, i.e. a 20-minute cycling bout at 65% of VO2peak, with (BFR) and without BFR (control) in random order, using a cycle ergometer. In the BFR condition, an occlusion cuff was used to regulate the occlusion pressure applied to both limbs that was proportional to thigh circumference. Mean oxygen uptake (VO2) during the 20 minutes exercise, VO2 recovery during the first minute of recovery (VO2/t slope), heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure at 6 min, 12 min and 18 min of exercise, fatigue and dyspnea perception were assessed. ANOVA or paired t-test was used for statistics and data are presented as mean±SD. RESULTS: Mean VO2 during exercise was higher in BFR compared to control (70.6±9.8% vs 64.0±10.1%, p=0.003), while VO2/t slope was higher in control (0.79±0.23 vs 0.53±0.11, p= 0.008). HR was higher during the BFR exercise (94±15 vs 88±15, 97±20 vs 90±19, 96±10 vs 84±9 at 6, 12 and 18 min, respectively; p<0.05), whereas SBP and DBP did not differ between the two conditions at any time point (p>0.05). Fatigue (12.4±2.7 vs 8.8±1.7, p=0.002) and dyspnea (11.5±2.5 vs 9.2±1.9, p=0.03) perception were significantly higher in BFR compared to control. CONCLUSIONS: To our knowledge, this is the first study examined BFR exercise in CHF patients, revealing specific cardiopulmonary and hemodynamic responses and suggesting that this exercise strategy is safe and feasible in those patients. More studies are needed to verify and further characterize the acute and chronic effects of BFR training in CHF patients.