Background: Clinical outcomes of patients with myocardial infarction are primarily determined by the successful restoration of myocardial reperfusion and the severity of coronary atherosclerosis.

Aim: To investigate the predictive value of Gensini score on ST-segment resolution (STR) in patients undergoing primary percutaneous coronary intervention (pPCI) for acute ST-elevation myocardial infarction (STEMI).

Methods: The present study prospectively included 114 consecutive patients (mean age 54 ± 10 years, 15 women) with STEMI who underwent successful pPCI. Sum of ST-segment elevation amount in millimetres was obtained before angioplastyand 60 min after pPCI. ΣSTR < 50% was accepted as a ECG sign of no-reflow phenomenon. Thrombus grading was calculated according to the results of coronary angiography, and Gensini score (GS-pPCI) was calculated after pPCI without incorporating culprit lesion. Patients were divided into two groups according to STR: those with STR(–), and those with STR(+). Patients were also analysed according to the infarct-related artery.

Results: GS-pPCI was significantly higher in patients with STR(–) (10.1 ± 11.8 vs. 22 ± 18.6, p = 0.005). GS-pPCI was inversely correlated with STR (r = –0.287, p = 0.002). In subgroup analysis, patients in the STR(–) group with culprit lesion in left anterior descending artery and left circumflex artery also showed higher GS-pPCI (10.9 ± 13.5 vs. 23.5 ± 21.3, p = 0.03 and 9.6 ± 8.7 vs. 24.1 ± 21, p = 0.04, respectively). High thrombus burden was also observed more frequently in patients with STR(–) (68% vs. 43%, p = 0.03). Multivariate logistic regression analysis demonstrated that GS-pPCI and high thrombus burden independently predicted inadequate STR (OR 1.07, 95% CI 1.03–1.12, p = 0.001 and OR 3.28, 95% CI1.11–9.72, p = 0.03, respectively).Conclusions: GS-pPCI and high thrombus burden play an important role in predicting inadequate STR in patients with STEMI treated with pPCI.