The impact of stenting on coronary blood flow in patients with ST segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

INTRODUCTION: In patients with ST segment elevation acute myocardial infarction (STEMI), primary percutaneous coronary intervention (PCI) has been shown to be superior to thrombolytic therapy for the restoration of normal coronary blood flow. However, depending on the technique used, no-reflow phenomenon is observed in some of these patients. METHODS: Data from 385 consecutive patients with STEMI who underwent primary PCI were evaluated. The coronary angiograms of the patients were reviewed. Thrombosis In Myocardial Infarction flow grades, corrected Thrombosis In Myocardial Infarction frame count (cTFC) values and degree of stenosis were measured before intervention using quantitative coronary angiography, after angioplasty and after stenting. Patients were divided into four groups according to the degrees of residual stenosis (RS) and cTFC values after angioplasty: group I (n=82, RS <50% and cTFC <28 frames), group II (n=50, RS >= 50% and cTFC <28 frames), group III (n=40, RS <50% and cTFC >= 28 frames), and group IV (n=46, RS >= 50% and cTFC >= 28 frames). RESULTS: In group I, the cTFC values were significantly higher after stenting than after angioplasty (21.8 +/- 8.9 frames versus 18.6 +/- 4.9 frames; P=0.02); on the other hand, in group IV cTFC values were significantly lower after stenting than after angioplasty (49.3 +/- 31.4 frames versus 63.8 +/- 27.4 frames; P=0.037). The cTFC values were similar after angioplasty and after stenting in groups II and III (19.6 +/- 5.0 frames versus 20.4 +/- 11.3 frames; P=0.37, and 57.8 +/- 26.9 frames versus 55.5 +/- 31.6 frames; P=0.433, respectively). CONCLUSION: Routine stent implantation during primary PCI is an effective way to reduce residual stenosis in patients with STEMI. However, it may be logical that the decision for immediate stent implantation during primary PCI should be made taking the results of angioplasty into consideration.