Impact of existing cardiovascular risk factors on the improvement of exercise tolerance in patients with coronary artery disease after PCI and CABG undergoing post-hospital cardiac rehabilitation
Authors: Smolis-Bak E , Kowalik I , Sloniewicz J , Rydzewska E , Korzeniowska-Kubacka I , Wolszakiewicz J , Dabrowski R 
Published: October 2022

Abstract

Background
Regular physical activity is crucial for treatment and prevention of cardiovascular diseases. Adaptive changes in response to regular physical exertion show individual variability, which depends on a number of internal and external factors. The aim of the study was to assess the effectiveness of early post-hospital rehabilitation and to analyze the factors which may influence the exercise tolerance in patients with coronary artery disease (CAD) treated with PCI and CABG.

Material and methods
The study included 334 patients (pts), men 75.1%, with CAD, treated with PCI (87.4%) or CABG (12.6%). Mean age of the study group was 61.1±10.9 years, mean BMI: 27.6±4.1 kg/m2, mean LVEF: 56.1±7.2%. The main risk factors for CAD were: dyslipidemias: 76%, hypertension: 64.7%, smoking: 28.7%, diabetes: 22.5%. The rehabilitation procedures lasted for 6–8 weeks. Pts participated in endurance training and general conditioning exercises with elements of resistance trainings. Before and after rehabilitation, all patients underwent a symptom-limited exercise test (ETT). In order to identify factors influencing the increase in tolerance of training loads, patients were divided into 2 groups: group 1 (198 pts, 59.3%) - pts with the training load which increased ≥50%, group 2 (136 pts, 40.7%) - pts with training loads which increased less, by &lt;50%.

Results
After rehabilitation, a significant improvement in the ETT parameters was observed: 5.7±1.3 vs. 6.8±1.7 METs, p&lt;0.001; the resulting load predicted for age: 81.5±22.5 vs. 93.7±22.89%, p&lt;0.001; tests duration: 352±106 vs. 436±136 sec., p&lt;0.001 and in the training loads obtained: 46.7±10.9 vs. 71.4±22.4 Watts, p&lt;0.001. On the other hand, after rehabilitation, a significant increase in the number of pts with supraventricular (24.2% vs 34.7%, p&lt;0.001) and ventricular (34.2% vs 40.5%, p&lt;0.02) arrhythmias was observed. There was no correlation between the increase in training load tolerance (Watt) and the METs increase in the final ETT. The increase in the tolerance of training loads of ≥50% during rehabilitation was significantly influenced by: younger age, p&lt;0.001, gender (men), p&lt;0.001, EF (&gt;50%), p&lt;0.003, absence of diabetes, p&lt;0.003, lower initial values of training loads, p&lt;0.003. The increase in workload (MET&gt;50%) in the final ETT was significantly influenced by age (younger patients), BMI (thinner subjects) and lower workload (MET) in the baseline test. Other factors: smoking, hypertension, dyslipidemia did not affect the training loads.

Conclusions
Early post-hospital rehabilitation improves physical performance. The factors which significantly influenced the increase in training load ≥50% after rehabilitation period were - younger age, male sex, higher LVEF, absence of diabetes and lower values of training loads at the beginning.

Funding Acknowledgement
Type of funding sources: None.