Background: Thrombus formation during coronary angioplasty may play a role in the restenosis process.
Methods: The effect of pretreatment with coumarins on 6-month angiographic outcome was studied. In addition, the effect of "optimal" anticoagulation, defined as an international normalized ratio >70% of the follow-up time in the target range, was studied. A total of 261 patients were assigned to aspirin alone (ASA group) and 270 patients to aspirin plus coumarins started 1 week before the procedure (coumarin group).
Results: The mean international normalized ratio was 2.7 +/- 1.2 at the start of the procedure and 3.1 +/- 0.5 during follow up. Quantitative coronary analysis was performed on 301 lesions in the ASA group and of 297 lesions in the coumarin group. At 6 months, the minimal luminal diameter was similar in the ASA and coumarin groups. Optimal anticoagulation, however, was an independent predictor of a larger minimal luminal diameter at follow up (P =.01).
Conclusion: Overall, coumarins do not improve angiographic outcome 6 months after coronary angioplasty.