Remote Ischemic Postconditioning: Does It Protect Against Ischemic Damage in Percutaneous Coronary Revascularization? Randomized Placebo-Controlled Clinical Trial

Study Questions:

What is the effect of remote ischemic postconditioning (RIP) on percutaneous coronary intervention-related myocardial infarction (PCI-MI)?

Methods:

This was a single-center, randomized, blinded to the researchers, clinical trial at a tertiary hospital center. A total of 232 patients underwent elective PCI for stable or unstable angina. Patients were randomized to RIP (induction of three 5-minute cycles of ischemia in the arm after the PCI) versus placebo. The primary outcome measure was the peak 24-hour troponin I level. PCI-MI was defined by an elevation of troponin values >3 or >5 of the 99th percentile according to the classical or the new definition. The secondary outcome measure was hospital admission, PCI for stable angina or acute coronary syndrome, and mortality after 1 year of follow-up. The use of RIP in diabetic patients was specifically studied.

Results:

The mean age was 64.6 years, and 42% were diabetic. The peak troponin in the RIP patients was 0.476 versus 0.478 ng/ml (p = 0.99). PCI-MI occurred in 36% of the RIP patients versus 30.8% in the placebo group (p = 0.378). Diabetic RIP patients had more PCI-MI (new definition): odds ratio, 2.7; 95% confidence interval, 1.10-6.92; p = 0.027. The secondary outcome measure was seen in 11.7% of the RIP patients versus 10.8% in the placebo group (p = 0.907).

Conclusions:

The authors concluded that RIP did not reduce the damage associated with elective PCI or cardiovascular events during the follow-up.

Perspective:

This prospective, randomized, controlled trial demonstrates that RIP, administered by transient upper-limb ischemia, does not affect PCI-related troponin release in patients undergoing elective PCI. Furthermore, among those randomized to the RIP, diabetes was associated with a 37% increase in the peak troponin levels compared with the nondiabetic patients, and the application of the new definition of PCI-MI resulted in a greater and significant incidence of PCI-MI in the diabetic patients who underwent RIP as compared with the controls. While the harm noted among diabetic patients needs further study, the future for RPI does not look promising.

Keywords: Incidence, Myocardial Infarction, Acute Coronary Syndrome, Follow-Up Studies, Troponin I, Angioplasty, Balloon, Coronary, Ischemic Postconditioning, Troponin, Percutaneous Coronary Intervention


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