Randomized Evaluation of the Effects of Filter-Based Distal Protection on Myocardial Perfusion and Infarct Size After Primary Percutaneous Catheter Intervention in Myocardial Infarction With and Without ST-Segment Elevation

Abstract

Background— In acute myocardial infarction, distal embolization of debris during primary percutaneous catheter intervention may curtail microvascular reperfusion of the infarct region. Our randomized trial investigated whether distal protection with a filter device can improve microvascular perfusion and reduce infarct size after primary percutaneous catheter intervention. Methods and Results— We enrolled 200 patients who had angina within 48 hours after onset of pain plus at least 1 of 3 additional criteria: ST-segment elevation, elevated myocardial marker proteins, and angiographic evidence of thrombotic occlusion. Among the patients included (83% men; mean age, 62±12 years), 100 were randomly assigned to the filter-wire group and 100 to the control group. The primary end point was the maximal adenosine-induced Doppler flow velocity in the recanalized infarct artery; the secondary end point was infarct size estimated by the volume of delayed enhancement on nuclear MRI. ST-segment elevation myocardial infarction was present in 68.5% of the patients; the median time from onset of pain was 6.9 hours. In the filter-wire group, maximal adenosine-induced flow velocity was 34±17 compared with 36±20 cm/s in the control group ( P =0.46). Infarct sizes, assessed in 82 patients in the filter-wire group and 78 patients in the control group, were 11.8±9.3% of the left ventricular mass in the filter-wire group and 10.4±9.4% in the control group ( P =0.33). Thirty-day mortality was 2% in filter-wire group and 3% in the control group. Conclusions— The filter wire as an adjunct to primary percutaneous catheter intervention in myocardial infarction with and without ST-segment elevation did not improve reperfusion or reduce infarct size.