Postconditioning Fails to Improve Outcomes in STEMI Patients Over Primary PCI Alone

MIAMI BEACH, FLA.—Ischemic postconditioning with primary PCI is not associated with improved myocardial reperfusion or clinical outcomes, according to data from the POST trial.

Joo-Yong Hahn, MD, of Sungkyunkwan University School of Medicine in Seoul, and colleagues conducted a multicenter, prospective, randomized, open-label, blinded-endpoint trial at 17 centers in South Korea to compare the safety and efficacy of primary PCI with (n=350) or without (n=350) postconditioning.

Before the index procedure, all patients received 300 mg aspirin and 600 mg clopidogrel. In the postconditioning group, immediately after restoration (TIMI grade ≥2) of coronary flow, an angioplasty balloon was positioned at the culprit lesion or stented segment and inflated four times for 1 minute per inflation at low pressure, with each instance of inflation separated by 1 minute of reflow.

Results revealed no significant differences between groups for the primary endpoint of complete ST-segment resolution >70% at 30 minutes postprocedure (see Figure 1), showing a rate of roughly 40% in both groups (P=.75). Baseline and follow-up ECG data were available for 315 of the 323 patients who completed four cycles of balloon occlusion immediately after reflow per protocol. Further analysis showed no benefit of postconditioning across various subgroups.

Similarly, researchers found no significant differences for secondary endpoints between the conventional and postconditioning groups. Patients who received postconditioning tended to have a higher rate of post-procedural TIMI flow grade 3 than those in the conventional PCI group, but statistical significance was not achieved (92% vs. 87.9%; P=.08). There was also no significant difference in post-procedural myocardial blush grade 0/1 between the two groups (17.2% vs. 22.4%; P=.2).

Additionally, at 1 month, clinical outcomes did not significantly differ between the postconditioning and conventional groups. MACE occurred in 4.3% of patients who received postconditioning and 3.7% of those who received conventional PCI (P=.7).

ST-segment resolution, myocardial blush grade and post-procedural TIMI flow grade were significantly associated with clinical outcomes at 1 month (see Figure 2).