Latin American randomized trial of balloon angioplasty vs coronary stenting for small vessels (LASMAL): immediate and long-term results.

PURPOSE: To assess the potential role of coronary stent to improved acute success and reduce late restenosis in lesions with reference diameter <2.9 mm using a bare metal stent specifically designed for small coronary vessels. There is controversy on the results among previous studies comparing bare metal stent implantation with conventional balloon percutaneous transluminal coronary angioplasty (PTCA). Differences in baseline characteristics, inclusion and exclusion criteria, and stent design may account for these discrepancies.

METHODS: The population of this multicenter, multinational randomized study (LASMAL) consisted of 246 patients undergoing percutaneous coronary intervention of small vessel reference diameter. They were randomized into 2 strategies of percutaneous revascularization: elective primary stent (n = 124) or conventional balloon PTCA with provisional stenting (n = 122) in the presence of acute, threatened closure or flow-limiting dissections.

RESULTS: The clinical success rate was significantly better for the stent group (98.3% vs 91.8%; P = 0.038). At 30 days follow-up, requirements of target vessel revascularization (TVR) (6.6% vs 0.8%; P = 0.018) and incidence of major adverse cardiac and cerebrovascular events (MACCE) (9.8% vs 2.4%; P = 0.01) was significantly lower in the stent strategy. Postpercutaneous coronary intervention minimal luminal diameter (MLD) was significantly larger in the stent group (2.3 +/- 0.2 mm vs 2.2 +/- 0.2 mm; P = 0.003). At follow-up, MLD in the stent group was larger than with PTCA (1.7 +/- 0.7 mm vs 1.5 +/- 0.7 mm, respectively; P = 0.035). Net gain was also significantly better with stent strategy (1.1 +/- 0.7 mm vs 0.8 +/- 0.7 mm, respectively; P = 0.002). Stenting resulted in a significant lower angiographic binary restenosis (20% vs 31%; P = 0.02) than PTCA. Furthermore, patients treated with stent were more frequently free from MACCE at 9-month follow-up (death, acute myocardial infarction [AMI], stroke, repeat revascularization procedures) than those treated initially with PTCA (82.2% vs 72% of PTCA, P = 0.046).

CONCLUSIONS: The use of a specifically designed bare metal coronary phosphoril choline-coated stent as primary device during percutaneous interventions in small coronary arteries was associated with high procedural success and low in-hospital and 30-day follow-up complications. At long-term follow-up, patients initially treated with stents had lower angiographic restenosis rate and were more frequently free from major adverse cardiac events.