Effects of high-intensity interval training in patients with coronary artery disease after percutaneous coronary intervention: a systematic review and meta-analysis

Background High-intensity interval training, for its characteristic of short-time high oxygen-consumption exercise interphase with periods of low-intensity training or rest for recovery, is easier to persist and execute in cardiac rehabilitation. However, it is little known whether HIIT program has an advantageous effect on patients after percutaneous coronary intervention or not. Methods Randomized controlled trials (RCTs) focusing on HIIT program in patients after PCI were searched in Cochrane Library, Web of Science Core Collection, EMbase, PubMed, China National Knowledge Infrastructure (CNKI) and SinoMed from the inception to March 24, 2020. Two reviewers conducted the literature retrieval, data extraction, and quality assessment independently. Standard Mean difference (SMD) and 95% confidence intervals (CI) were performed to summarize the effect sizes. Results 6 RCTs (247 patients) met the criteria. HIIT program had a statistically significant effect on raising left ventricular ejection function (LVEF) (SMD=0.38, 95%CI[0.03, 0.73], p=0.03), VO 2peak (SMD=0.94, 95%CI[0.61, 1.28], p<0.01), as well as improving the serum level of high-density lipoprotein (SMD=0.55, 95%CI[0.06, 1.03], p=0.03) and late luminal loss (SMD=−0.65, 95%CI[−1.07, −0.23], p<0.01). But HIIT had no prominent effect on improving heart rate (SMD=−0.04, 95%CI[-0.29, 0.21], p=0.73). Conclusions HIIT program might be favorable for CAD patients after PCI by improving cardiopulmonary function, such as LVEF and VO 2peak , as well as reducing late luminal loss in per stented arteries. Nevertheless, HIIT had no advantage for adjusting heart rate. More researches with rigorous methods are warranted to explore the controversy about lipid profiles.