Association between ST segment Resolution following Fibrinolytic therapy or Intracoronary stenting, and Reinfarction in the same myocardial region in the DANAMI-2 study population

BackgroundST-segment resolution has long been used as one of several clinical markers of response to reperfusion therapy. With the use of the DANish trial in Acute Myocardial Infarction-2 (DANAMI-2) database, this case–control study tests the hypothesis that incomplete ST-segment resolution (<70%) will be predictive of the risk of reinfarction in the same myocardial region regardless of the reperfusion therapy employed.Methods and resultsOne hundred forty-nine (9.5%) patients with clinical reinfarction were matched to patients with no documented reinfarction (“no reinfarction”). With the use of the initial DANAMI-2 and reinfarction electrocardiograms, 80 patients were found to have reinfarction in the same myocardial region (“reinfarction”). “Reinfarction” and their matched “no-reinfarction” patients were included (n=160), and prereperfusion and postreperfusion ST segments were measured manually.Of all “reinfarction” patients, 66% (53 of 80) had incomplete ST-segment resolution [P=.13; odds ratio (OR)=1.69]. Stratified by the reperfusion strategy employed, this corresponded to 67% (35 of 52) being treated with fibrinolytics (P=.45; OR=1.33), suggesting that these patients were equally likely to reinfarct in the same myocardial region regardless of the degree of ST-segment resolution. In the primary percutaneous coronary intervention (pPCI) arm, 64% (18 of 28) of patients with reinfarction in the same myocardial region had incomplete ST-segment resolution (P=.10; OR=6.0). In the pPCI arm, the trend was that patients with incomplete ST-segment resolution were more likely to reinfarct in the same myocardial region than those with complete ST-segment resolution, but these findings did not reach statistical significance. No statistically significant difference was found in the association of reinfarction in the same myocardial region and ST-segment resolution between the two treatment arms (P=.11).ConclusionThe results from this study suggest that, although fibrinolytic-treated patients are more likely to reinfarct in the same myocardial region than pPCI-treated patients, there is no clear statistically significant association between ST-segment resolution and reinfarction in the same myocardial region. Trends in the data suggest that fibrinolytic-treated patients are equally likely to reinfarct in the same myocardial region regardless of the degree of ST-segment resolution. However, the trend in the pPCI population is such that incomplete ST-segment resolution is associated with a higher likelihood of reinfarction in the same myocardial region.