Coronary stenting in unstable angina: angiographic and clinical implications

The pathogenesis of unstable angina involves the presence of intracoronary thrombus which may have potential bearing on the therapeutic efficacy of intracoronary stenting to reduce acute complications and restenosis rate.

In order to evaluate in-hospital and long-term outcome of coronary stenting in patients with unstable angina, we retrospectively examined our experience in 311 consecutive patients. Braunwald class III angina (B or C) was present in 35% of the cases. Three hundred seventy one stents were implanted in 315 lesions, most of them (62.4%) with complex morphology. Angiography identified an intraluminal thrombus in 22 target sites. Stent indication was elective in 146 cases (46.9%), for suboptimal results in 149 (47.9%) and for bail-out in 16 (5%).

Procedural success was obtained in 96.3% of the study population. Major complications occurred in 12 (3.7%) patients: myocardial infarction in 6 (1.9%) cases, emergency bypass surgery in 3 (0.9%) and death in 3 (0.9%), none of them related to acute stent thrombosis. Vascular complications occurred in 5 patients (1.6%). The mean hospital stay after stenting was 2.8 +/- 1.6 days. Subacute stent thrombosis occurred in one patient and led to a Q-wave anterior myocardial infarction. Follow-up (9 +/- 5 months) status was ascertained in 216 patients and revealed an overall clinical success rate of 87.3%. Restenosis occurred in 23.5% of 157 patients who underwent angiographic follow-up. Late events included 3 non-fatal myocardial infarction, 6 new PTCA, 3 elective bypass surgery and 1 cardiac death.

Intracoronary stenting appears safe and effective in patients with unstable angina, despite the presence of a thrombogenic milieu. Optimal immediate angiographic results, related to the mechanical properties of stents, together with a vigorous antithrombotic regimen, contributes to the favorable outcomes in this adverse setting.