Effect of tirofiban therapy on ST segment resolution and clinical outcomes in patients with ST segment elevated acute myocardial infarction undergoing primary angioplasty

Background. In our study, we assessed the effect of glycoprotein (GP) Ilb/IIIa receptor inhibition on microvascular flow after acute coronary occlusion using the early sum of ST segment resolution in electrocardiography. Platelets may play a major role in the dissociation of epicardial artery recanalization and tissue level reperfusion, referred to as the 'no-reflow phenomenon'. Therefore, GP IIb/IIIa receptor inhibition might improve myocardial reperfusion, distinct from its effects on epicardial patency. Methods and Results: One hundred and fifteen patients (mean age 57.7 +/- 12.2 years, 96 males, 19 females) with <= 12-hour acute ST segment elevation myocardial infarction who underwent successful primary percutaneous coronary intervention were retrospectively enrolled into the study. Patients were grouped according to whether they received tirofiban therapy or not. Clinical and electrocardiographic parameters were evaluated. The first sum of ST segment elevation amounts in millimeters was obtained immediately before angioplasty and the second 60 min after restoration of thrombolysis in myocardial infarction III flow. The difference between the two measurements was accepted as resolution of the sum of ST segment elevation and expressed as Sigma STR. There were no significant differences between the groups regarding age, gender, cardiovascular risk factors, and laboratory parameters, duration from angina onset to the emergency unit, and from door to angioplasty. Sigma STR was higher in patients who received tirofiban than in those who did not (7.2 +/- 2.8 and 4.2 +/- 2.6 mm, respectively; p < 0.001). There was a significant and positive correlation between GP IIb/IIIa inhibition and Sigma STR (r = 0.336, p < 0.001), as well as between ejection fraction and Sigma STR (r = 0.310, p < 0.001). GP IIb/IIIa inhibition was the only independent determinant of Sigma STR in a multivariate linear regression model which contains 10 variables (p < 0.001). The incidence of in-hospital post-myocardial infarction refractory angina, reinfarction, and heart failure was significantly lower in the tirofiban group (p < 0.05, p < 0.05, and p < 0.05, respectively). Additionally, after 30 days, reinfarction and heart failure were lower in the tirofiban group (p < 0.05 and p < 0.05, respectively). Conclusions: It is well known that Sigma STR determines microvascular perfusion. This study shows that GP IIb/ IIIa inhibition with tirofiban is of value in preserving microvascular perfusion after restoring coronary thrombolysis in myocardial infarction III flow.