Long-term Luminal Renarrowing After Successful Elective Coronary Angioplasty of Total Occlusions
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Background The long-term angiographic outcome after successful dilatation of coronary occlusions remains unclear. The objective of this study was to examine long-term restenosis after successful balloon dilatation of coronary occlusions at a predetermined time interval with quantitative angiography and compare this with a control population of stenoses. Methods and Results The study population comprised 2950 patients (3583 lesions) prospectively enrolled in and successfully completing four major restenosis trials (86% quantitative angiographic follow-up). Cineangiographic films were processed and analyzed at a central core laboratory with the use of an automated interpolated edge detection technique. The study population comprised 266 occlusions (7%) defined as total when there was absent anterograde filling beyond the lesion (109 lesions) and functional (157 lesions) when faint, late anterograde opacification of the distal segment was seen in the absence of a discernible luminal continuity; 3317 lesions were defined as stenoses (93%). Restenosis was significantly higher after successful dilatation of occlusions than of stenoses. With the categorical (>50% diameter stenosis at follow-up) approach, the restenosis rate was 44.7% in occlusions compared with 34.0% in stenoses (P<.001; relative risk, 1.575; CI, 1.224 to 2.027). Similarly, the absolute loss (defined as the change in minimal lumen diameter between post coronary angioplasty and follow-up; in millimeters, mean±SD) (0.43±0.68) in occlusions was significantly higher than in stenoses (0.31±0.51, P<.001), as was the relative loss, defined as the change in minimal lumen diameter between postangioplasty and follow-up, adjusted for the vessel size (0.17±0.28 versus 0.12±0.20, P<.001). The higher restenosis rate in the occlusions group was due predominantly to an increased number of occlusions at follow-up angiography in this group (19.2% compared with 5.0% for stenoses, P<.001). Within the occlusions group, there were no significant differences in long-term outcome between total and functional occlusions (restenosis rate, 45.0% versus 44.6%; reocclusion rate, 23.9% versus 15.9%; absolute loss, 0.53±0.69 versus 0.36±0.67; relative loss, 0.21±0.28 versus 0.15±0.28; P=NS). Conclusions These results indicate that successfully dilated coronary occlusions, both total and functional, have a higher rate of angiographic restenosis at 6 months than stenoses. This is due chiefly to a higher rate of occlusion at follow-up angiography in this group of lesions. Measures aimed at reducing restenosis after successful dilatation of coronary occlusion should be focused in this direction.