[Evaluation of small branch occlusion and myocardial damage related to angioplasty. Usefulness of determining serum CK-MB].

In 65 consecutive cases of PTCA we prospectively looked for the appearance of myocardial necrosis during PTCA and for the presence of occlusion of collateral branches arising from the inflation area. Premedication was oral in 44 and intramuscular in 21 cases. CK-MB was abnormally increased in 6 cases: 3 with total occlusion of the dilated artery, 1 with transient coronary occlusion, and 1 with occlusion of a collateral branch greater than 1 mm diameter; in the sixth case the increased CK-MB peak was attributed to repeated defibrillations. Only 1 collateral branch less than 1 mm was occluded during PTCA though myocardial necrosis was not detected. Only collateral branches arising from the dilated stenosis were affected (occlusion and/or appearance of new stenosis) by PTCA (4/24 vs 0/162; p less than 0.01). There were no significant differences in CK-MB peak between both types of premedication. Thus we conclude that: 1) in PTCA myocardial necrosis is only induced by occlusion of coronary arteries greater than 1 mm diameter; 2) only collateral branches arising from the dilated stenosis are at risk of occlusion; 3) estimation of CK-MB pre-PTCA and 8 hours post-PTCA are sufficient for detection of myocardial necrosis.