Ventilatory Muscle Training for Early Cardiac Rehabilitation Improved Functional Capacity and Modulated Vascular Function of Individuals Undergoing Coronary Artery Bypass Grafting: Pilot Randomized Clinical Trial

Background: Cardiac rehabilitation with aerobic exercises is the first strategy for non-pharmacological treatment in the postoperative period of individuals undergoing coronary artery bypass grafting (CABG) to improve functional capacity and vascular health. However, other exercise modalities remain uncertain regarding the same benefits. Objectives: Evaluation of the effect of different modalities of exercise, such as early cardiac rehabilitation on subjects submitted to CABG in the six-minute walk test (6-MWT) and on the percentage of flow-mediated dilatation (FMD) of the brachial artery. Methods: A randomized clinical trial in which 15 patients (62.7 +/- 6.7 years) who underwent CABG were randomly assigned to the following groups: isometric (IG, Handgrip Jamar (R)), ventilatory muscle training (VG, PowerBreathe (R)) and control (CG, conventional respiratory and motor physiotherapy). All patients were attended to physically twice a day (20 min/session) for a consecutive week after the CABG (hospital admission). Functional capacity was assessed by 6-MWT and endothelial function was assessed through the technique of FMD, before and after (similar to 7 days) admission to CABG. The doppler ultrasound videos were analyzed by Cardiovascular Suite (R) software (Quipu, Pisa, Italy) to measure %FMD. Statistics: Generalized estimation equation, followed by Bonferroni post hoc (p < 0.05). Results: Systolic, diastolic and mean arterial pressure (SBP/DBP/MAP, respectively) were 133, 76 and 95 mmHg. The groups presented walking meters (m) distance before and after intervention of: IG(basal) 357.80 +/- 47.15 m vs. IG(post) 306.20 +/- 61.63 m, p = 0.401 (+51 m); VG(basal) 261.50 +/- 19.91 m vs. VG(post) 300.75 +/- 26.29 m, p = 0.052 (+39 m); CG (basal) 487.83 +/- 83.23 m vs. CG(post) 318.00 +/- 31.08, p = 0.006 (-169 m). %FMD before and after intervention was IG(basal) 10.4 +/- 4.8% vs. IG(post) 2.8 +/- 2.5%, p = 0.152; VG(basal) 9.8 +/- 5.1% vs. VG(post) 11.0 +/- 6.1%, p = 0.825; CG(basal) 9.2 +/- 15.8% vs. CG(post) 2.7 +/- 2.6%, p = 0.710 and resting mean basal blood flow was IG(basal) 162.0 +/- 55.0 mL/min vs. IG(post) 129.9 +/- 63.7 mL/min, p = 0.662; VG(basal) 83.74 +/- 12.4 mL/min vs. VG(post) 58.7 +/- 17.1 mL/min, p = 0.041; CG(basal) 375.6 +/- 183.7 mL/min vs. CG(post) 192.8 +/- 115.0 mL/min, p = 0.459. Conclusions: Ventilatory muscle training for early cardiac rehabilitation improved acute functional capacity and modulated mean flow of individuals undergoing CABG.

Automated summary

The study evaluated the effect of early cardiac rehabilitation on the 6-minute walk test and vascular function in patients undergoing coronary artery bypass grafting. The results showed that ventilatory muscle training improved both functional capacity and blood flow in these patients.