Does a well developed collateral circulation predispose to restenosis after percutaneous coronary intervention? An intravascular ultrasound study.

OBJECTIVE: To evaluate whether a well developed collateral circulation predisposes to restenosis after percutaneous coronary intervention (PCI). DESIGN: Prospective observational study. PATIENTS AND SETTING: 58 patients undergoing elective single vessel PCI in a tertiary referral interventional cardiac unit in the UK. METHODS: Collateral flow index (CFI) was calculated as (Pw-Pv)/(Pa-Pv), where Pa, Pw, and Pv are aortic, coronary wedge, and right atrial pressures during maximum hyperaemia. Collateral supply was considered poor (CFI < 0.25) or good (CFI > or = 0.25). MAIN OUTCOME MEASURES: In-stent restenosis six months after PCI, classified as neointimal volume > or = 25% stent volume on intravascular ultrasound (IVUS), or minimum lumen area < or = 50% stent area on IVUS, or minimum lumen diameter < or = 50% reference vessel diameter on quantitative coronary angiography. RESULTS: Patients with good collaterals had more severe coronary stenoses at baseline (90 (11)% v 75 (16)%, p < 0.001). Restenosis rates were similar in poor and good collateral groups (35% v 43%, p = 0.76 for diameter restenosis, 27% v 45%, p = 0.34 for area restenosis, and 23% v 24%, p = 0.84 for volumetric restenosis). CFI was not correlated with diameter, area, or volumetric restenosis (r2 < 0.1 for each). By multivariate analysis, stent diameter, stent length, > 10% residual stenosis, and smoking history were predictive of restenosis. CONCLUSION: A well developed collateral circulation does not predict an increased risk of restenosis after PCI.

Clopidogrel for prevention of major cardiac events after coronary stent implantation: 30-day and 6-month results in patients with smaller stents.

OBJECTIVES: We developed this study to assess the procedural outcome, complications, and clinical follow-up in patients treated with different antiplatelet regimens after intracoronary stent implantation with small stents. Three hundred sixty-one consecutive patients, in whom at least one 3.0-mm intracoronary stent was implanted, were studied. METHODS: The study was a prospective, observational registry of unselected consecutive patients treated in our institution. Patients who underwent stent implantation between December 1997 and July 1998 were treated with aspirin and ticlopidine; those who received stents between August 1998 and February 1999 were treated with aspirin and clopidogrel. RESULTS: In the group treated with ticlopidine, there were 190 patients who had 253 lesions treated with 274 stents. Mean age was 59.1 years, 72% were male, 31% had unstable angina, 64% had 1 stent, 36% had >1 stent, and 23% had multivessel intervention. In the group treated with clopidogrel, there were 171 patients who had 226 lesions treated with 245 stents. Mean age was 60.4 years, 79% were male, 26% had unstable angina, 70% had 1 stent, 30% had >1 stent, and 26% had multivessel intervention. Complications at 30 days in the ticlopidine group were death in 1 (0.5%), stent occlusion in 3 (1. 6%; all reopened with repeat angioplasty), non-Q-wave myocardial infarction in 2 (1%), and urgent revascularization in 4 (2%). Complications at 30 days in the clopidogrel group were noncardiac death in 1 (1.2%), cardiac death in 1 (1.2%), stent occlusion in 0, non-Q-wave myocardial infarction in 3 (1.8%), and urgent revascularization in 0. Follow-up was available in 100% of patients in both groups (mean 253 +/- 75 days in the ticlopidine group, 198 +/- 53 days in the clopidogrel group). Complications at >30 days in the ticlopidine group were death in 1 and clinical restenosis in 11 (5.8%); 1 additional patient had an admission with unstable angina to the local hospital. Hence, recurrent angina as a consequence of target lesion restenosis occurred in 5.8%. Complications at >30 days in the clopidogrel group were death in 0 and clinical restenosis in 8 (4.7%); 2 additional patients were admitted with unstable angina to the local hospital, and 1 patient had a myocardial infarction 164 days after stent implantation. Hence, recurrent angina as a consequence of target lesion restenosis occurred in 4.7%. There were no significant differences in complications between the 2 groups. CONCLUSIONS: Our observations suggest that clopidogrel can be used instead of ticlopidine in patients treated with stents with a diameter of