STEMI outcomes unrelated to time to balloon inflation

The time delay of balloon inflation does not seem to affect adverse outcomes in ST-segment elevation myocardial infarction (STEMI) patients presenting with ischaemic signs >12 hours after initial symptom onset, a recent study has found.

Of the 825 consecutive STEMI patients, 298 received balloon inflation ≤7 days after symptom onset (early group; mean age, 57±11 years; 71.8 percent male), while 527 underwent the procedure after >7 days had elapsed (late group; mean age, 58±12 years; 75.5 percent male). The primary endpoints were all-cause mortality and nonfatal recurrent MI.

In the overall study cohort, the likelihood of recurrent nonfatal MI was significantly elevated in the early intervention group (hazard ratio [HR], 1.925, 95 percent CI, 1.001–3.697; p=0.049). This remained true even after propensity score matching (HR, 2.097, 1.012–4.345; p=0.046).

Cox multivariate analysis, on the other hand, showed that while the time to balloon inflation was a significant predictor of nonfatal, recurrent MI before propensity matching (HR, 2.150, 1.122–4.121; p=0.021), its effect was attenuated after adjustments (HR, 2.204, 0.994–4.889; p=0.052).

Moreover, stratifying the patients according to the number of compromised vehicles, researchers found that the time delay to balloon inflation was only significant in those with multivessel coronary artery disease.

The risk of death, in comparison, was comparable between the early and late groups in both the pre- (HR, 0.657, 0.326–1.322; p=0.238) and postmatched (HR, 1.292, 0.485–3.444; p=0.651) cohorts. This was confirmed in multivariate analysis.