Coronary vasomotion and exercise-induced adaptations in coronary artery disease patients: A systematic review and meta-analysis

BACKGROUND: Exercise can improve coronary blood flow in a healthy heart, but the vascular response of patients with coronary artery disease (CAD) is different. The aim of this study was to systematically review the chronic effects of exercise on coronary arterial function in CAD patients. MATERIALS AND METHODS: Six electronic databases (PubMed, ScienceDirect, “Scopus,” Web of Science, EMBASE, and Google Scholar) covering publications from 1986 to 2019 were systematically searched with related keywords. Studies were included if they investigated changes in blood flow and coronary artery diameter in response to chronic exercise training in patients with CAD. A total of 5421 studies were assessed for quality and outcomes, and finally five studies met criteria for inclusion. For metaanalysis, the results of the studies were pooled using the randomeffects model. The heterogeneity between the studies was checked using I(2) index. RESULTS: The total sample population consisted of 108 CAD patients. According to the findings of this study, coronary artery function in adaptation with exercise showed that a period of exercise leads to statistically significant improvement in coronary flow velocity reserve (z = 3.15, P = 0.002; standardized mean difference [SMD] =2.33, 95% confidence interval [CI]: 0.88–3.78) (containing six trials). In addition, vasodilatory response of coronary arteries in response to endothelium-independent vasodilator nitroglycerin was investigated in three studies (containing four trials). A meta-analysis showed that performing chronic aerobic exercises did not make a significant change in the endothelium-independent vasodilator (z = 0.83, P = 0.40; SMD = −0.36, 95% CI: −1.21–0.49). CONCLUSION: Based on the results of the present study, aerobic exercises improve the endothelial function of coronary arteries and thereby the vascular vasomotion function, while the results of this meta-analysis showed no change in arterial smooth muscle's function by chronic aerobic exercises. This study reflects the lack of high- and medium-quality reports about the chronic effects of anaerobic and resistance exercises and the various methods of aerobic exercise on cardiovascular function.