EXAGGERATED LUMINAL LOSS A FEW MINUTES AFTER SUCCESSFUL PERCUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY IN PATIENTS WITH RECENT MYOCARDIAL-INFARCTION COMPARED WITH STABLE ANGINA - AN INTRACORONARY ULTRASOUND STUDY

This study investigates the mechanisms of exaggerated acute luminal lo ss after successful coronary angioplasty in patients with recent myoca rdial infarction compared with stable angina by angiography and intrac oronary ultrasound (ICUS). We studied 15 consecutive patients (group 1 ) who, after a successful thrombolysis for myocardial infarction, unde rwent delayed (8 +/- 2 days after the myocardial infarction) successfu l balloon coronary angioplasty. Group 1 patients were individually mat ched with 15 stable angina patients (group 2). The percentage of steno sis and acute luminal loss were measured by quantitative coronary anal ysis. The ultrasound characteristics of lumen pathology were described as soft, hard, calcified, eccentric, concentric, thrombotic, and diss ection lesions. Matching by stenosis location, reference diameter, sex , and age resulted in 2 comparable groups of 15 lesions with identical baseline characteristics. Immediately after percutaneous transluminal coronary angioplasty (PTCA), the minimal luminal diameter increased f rom 0.5 +/- 0.3 mm to 2.4 +/- 0.3 mm and from 0.5 +/- 0.2 mm to 2.4 +/ - 0.3 mm in groups 1 and 2, respectively. Similar balloon sizes were u sed in both groups. The acute luminal loss (the difference between the maximal dilated balloon diameter and the minimal luminal diameter) im mediately after PTCA was 0.4 +/- 0.2 mm and 0.3 + 0.3 mm (14 +/- 8% an d 10 a 11% of balloon size) (P = not significant [NS]) in groups 1 and 2, respectively. After ICUS (mean 24 min after the last balloon defla tion), the acute luminal loss was 0.9 +/- 0.3 mm and 0.5 +/- 0.4 mm (2 9 +/- 11% and 17 +/- 8% of balloon size) (P = 0.01) in groups 1 and 2, respectively. There was a significantly higher prevalence of intracor onary thrombus formation as detected by ICUS in group 1 compared with group 2 (80% vs, 20%; P < 0.001). In matched groups of successfully tr eated coronary angioplasty, patients with recent myocardial infarction had a similar magnitude of acute gained luminal loss immediately afte r the procedure. However, an exaggerated luminal loss a few minutes af ter the last balloon deflation in patients with recent myocardial infa rction was noted because of mural thrombus formation compared with pat ients with stable angina. (C) 1997 Wiley-Liss, Inc.