Therapeutic dissection after successful coronary balloon angioplasty: No influence on restenosis or on clinical outcome in 693 patients

Objectives. The objective of this study was to examine the relation between an angiographically visible coronary dissection immediately after successfulcoronary balloon angioplasty and a subsequent restenosis and long-term clinical outcome. Background. The study population comprised all 693 patients who participated in the MERCATOR trial (randomized, doubleblind, placebo-controlled restenosis prevention trial of cilazapril, 5 mg two times a day). Methods. Cineangiographic films were processed and analyzed al a central angiographic core laboratory, without knowledge of clinical data, with use of an automated interpolated edge detection technique. Dissection was judged according to the National Heart, Lung, and Bund Institute classification. Angiogiaphic follow-up was obtained in 94% of patients with 778 lesions. Two approaches were used to assess the restenosis phenomenon: 1) categoric, using the traditional cutoff criterion of > 50% diameter stenosis at follow-up, and 2) continuous, defined as absolute change in minimal lumen diameter (mm) between the postcorouary angioplasty and follow-up, adjusted for the vessel size (relative loss). Clinical outcome was ranked accenting to the most serious adverse clinical event per patient during the 6-month follow-up period, ranging from death, nonfatal myocardial infarction, coronary revasculanzation and recurrent angina requiring raedical therapy to none of these. Results. Dissection was present in 247 (32%) o(He 778 dilated lesions. The restenosis rate was 29% in fesions with and 30% in lesions without dissection (relative risk 0.97;95% confidence interval 0.77 to 1.23). The relative loss in both groups was 0.10 (mean difference 0; 95% confidence interval -0.03 to 0.03). Clinical outcome ranged Irani death in 4 patients (0.9%) without dissection and I patient (0.4%) with dissection; nonfatal myocardial infarction in 4 (0.9%) without and 8 (3.2%) with dissection; coronary revascularizalion in 73 (16.6%) without and 32 (12.7%) with dissection; recurrent angina requiring medical therapy in 88 (20%) without and 47 (18.7%)with dissection serious adverse event in 272 (61.7%) without and 114 (65.1%) with dissection. Conclusions. These data indicate that a successfullydilated coronary lesion with an angiographically visible dissection is no more likely to develop restenosis, and is not associated with a worse clinical outcome, at 6-month follow-up than is a dilated lesion without visible dissection on the post-balloon angioplasty angiogram.