Patient, Lesion, and Procedural Variables as Risk Factors for Luminal Re-Narrowing After Successful Coronary Angioplasty

Summary: Follow-up angiography at 6 months was obtained in 94% of the 693 patients (778 successfully dilated coronary lesions) enrolled in the Multicenter European Research trial with Cilazapril after Angioplasty to prevent Transluminal Coronary Obstruction and Restenosis (MERCATOR) trial—a double-blind, placebo-controlled trial—to study the effects of cilazapril 5 mg b.i.d. on restenosis [defined as the mean loss in minimal luminal diameter during follow-up, assessed by an interpolated edge detection technique (coronary angiography analysis system)] and long-term clinical outcome. No statistically significant difference could be detected between treatment and placebo groups with regard to clinical outcome or restenosis. The purpose of this ancillary study was to determine which, if any, patient, lesion, or procedural factors were predictive of restenosis. The identification of such factors could be helpful in the selection of lesions suitable for angioplasty and, if modifiable or controllable, potentially reduce restenosis. A stepwise multiple linear regression analysis was performed to identify independent predictors of restenosis. The following variables were retained in the model in order of significance: (a) relative gain (difference between the minimal luminal diameter pre- and post-percutaneous transluminal coronary angioplasty (PTCA), normalized for vessel size), (b) minimal luminal diameter post-PTCA, and (c) dilatation of another vessel than right coronary artery. The fit of the model was poor; where the predicted change in minimal luminal diameter was <0.1 mm, 0.1-0.3 mm, >0.3 mm, the corresponding percent correct classification was 30, 52, and 55%. The present study illustrates that the restenosis phenomenon cannot accurately be predicted by patient, lesion, and procedural variables.