Background: Primary angioplasty has been shown to improve outcomes in selected patients with ST-segment elevation myocardial infarction. However, no information has been reported so far in small vessels. In the Zwolle-6 randomized trial, consecutive patients with ST-segment elevation myocardial infarction were randomized to stenting or to balloon angioplasty without any exclusion criterion. In this study, we present data on patients with small vessels (< 3.0 mm).
Methods: From April 1997 to October 2001, 798 patients randomized to balloon angioplasty or to stenting before their initial angiogram underwent primary angioplasty of small vessels, defined according to a postprocedural reference diameter < or = 3 mm. One-year follow-up data were available from all patients.
Results: Three hundred eighty-seven patients were randomized to stent, whereas 411 were to balloon. The crossover rates from balloon to stent and from stent to balloon were 28% and 13.9%, respectively (P < .001). The groups were comparable in terms of postprocedural TIMI flow, myocardial blush grade, distal embolization, and ST-segment resolution. No difference was observed in 1-year mortality (7.2% vs 5.8%, P = not significant [NS]), target vessel revascularization (17.8% vs 22.1%, P = NS), and major adverse cardiac events (24.8% vs 29.0%, P = NS) between the groups.
Conclusions: As compared with balloon angioplasty, routine stenting does not seem to improve clinical outcomes in patients undergoing primary angioplasty of small vessels. Future trials are certainly needed to evaluate the safety and benefits of drug-eluting stents in this high-risk subset of patients.