Impact of stent length on restenosis in patients with acute myocardial infarction treated with primary percutaneous coronary intervention: Analysis based on data from the Trial to Assess the Use of the Cypher Stent in Acute Myocardial Infarction Treated with Balloon Angioplasty (TYPHOON)

Aims: Stent length is a major predictor of restenosis in stable patients undergoing percutaneous coronary intervention (PCI) with bare metal stents (BMS). The effect of stent length is decreased by using drug eluting stents, however, this association had not been previously determined in patients with acute myocardial infarction (AMI). We sought to determine the impact of stent length on restenosis in patients who undergo primary PCI for AMI. Methods and results: Three-hundred and fifty-seven and 355 patients with AMI were included respectively in the BMS and SES (sirolimus eluting stents) arms of the Trial to Assess the Use of the Cypher Stent in Acute Myocardial Infarction Treated with Balloon Angioplasty (TYPHOON). Patients were divided into four subgroups based on the total length of the culprit lesion stented segment (in mm): <18, ≥18 and <23, ≥23 and < 28, and ≥28 (groups 1 - 4 respectively). Target lesion revascularisation (TLR) and angiographic late loss were used to assess the restenotic process. Despite similar lesion length, average stent length was longer in patients treated with SES as compared to BMS 22.1±8.6 and 20.3±8.2 mm respectively, p=0.005. The rate of 12m death and AMI was similar in SES and BMS. There was no significance influence of stent length on % TLR neither in BMS (12.6, 10.1, 17.4 and 12.3 - subgroups 1-4 respectively) nor in SES (3.9, 5, 2.2 and 2.7 respectively). There was also no significant impact of stent length on angiographic late loss (mm) neither in BMS (0.7, 0.87, 0.84 and 0.92 respectively) nor in SES (0.32, 0.0, 0.11 and 0.3 respectively). Conclusions: Physicians tend to choose longer SES than BMS for a similar lesion length during primary PCI for AMI. Interestingly, stent length did not affect clinical or angiographic restenosis neither in BMS nor in SES in this group of patients who underwent primary PCI for acute MI. This data challenges current practice concerning the chosen stent length in patients with AMI.