Postconditioning in patients treated with primary percutaneous coronary intervention: an updated meta-analysis

The aim of present analysis was to evaluate the effect of postconditioning in primary percutaneous coronary intervention (pPCI).

Although postconditioning in pPCI has shown potential favorable effects on reperfusion injury, recent trials have yielded divergent results.

Randomized controlled trials were identified using relevant databases published up to August 15, 2012. Weighted mean difference (WMD) and standardized mean difference (SMD) were calculated using meta-analysis through fixed- or random-effects models. Statistical analysis was performed using RevMan 5.17 and Stata 12.0.

Thirteen studies providing myocardial biomarkers, left ventricular ejection fraction (LVEF) or infarct size evaluated by cardiac magnetic resonance (CMR) in a total of 725 ST-elevation acute myocardial infarction (STEMI) patients were identified. Compared with usual care, postconditioning significantly reduced myocardial injury biomarkers (SMD = -0.61; 95% Confidence Interval (CI): [-0.98, -0.23]; P = 0.001; I(2) = 78%). Univariate meta-regression analysis suggested potential source of heterogeneity were the type of biomarkers and the use of glycoprotein IIb/IIIa inhibitors (I(2) reg = 44.84% and 67.24%, respectively; R(2) = 91.53% and 49.46%, respectively). Secondary analysis showed statistical significant improvement of LVEF with postconditioning (WMD = 3.22%; 95%CI: [0.88%, 5.57%]; P = 0.007; I(2) = 60%) relative to usual care. The effect diminished during medium (<6 months) and long terms (≥6 months) (P = 0.86 and 0.15, respectively). There was no significant decrease in infarct size among patients treated with postconditioning compared to usual care (SMD = 0.20; 95%CI: [-0.03, 0.43]; P = 0.08; I(2) = 46%).

In STEMI patients undergoing pPCI, postconditioning is associated with significant lower level of myocardial injury biomarkers and a statistical significant improvement of LVEF relative to usual care. However, this adjunctive therapy may fails to reduce infarct size evaluated by CMR.