An overview of US coronary stent trials.

Since the introduction of coronary stent procedures in the US there has been a determined effort to understand appropriate clinical applications better through the use of carefully designed prospective clinical trials. These studies fall into the general categories of efficacy studies, pharmacology, studies, intravascular ultrasound studies, adjuvant stent therapy studies, stent versus stent studies and new stent registries. Most of the pivotal clinical trials have been randomized controlled studies, but there have also been several carefully performed registry analyses which have provided useful insights. There are ample data to support the use of stents for abrupt and threatened closure syndrome. STRESS (the STent REStenosis Study) helped to establish the 'anti-restenosis' efficacy of elective Palmaz-Schatz coronary stent placement in native coronary arteries, although secondary complications (subacute stent thrombosis, bleeding and vascular events) were disturbing owing to excessive systemic anticoagulation regimens. Subsequent studies, often using intravascular ultrasound guidance, have clearly indicated that optimal stent implantation requiring post-stent high-pressure dilatations combined with aggressive antiplatelet therapy (aspirin plus ticlopidine) provides the best early and late clinical outcomes. Many of these observations have now been extended to other lesion subsets including saphenous vein grafts. In the future, stent adjuvant therapies will be carefully evaluated, including pharmacological agents, intravascular irradiation, and pre-stent atheroablation. Finally, interstent comparisons of randomized clinical trials are ongoing and there are several new stent registries which will help to extend the frontiers of clinical applications and operator technique.