[Estimation of perioperative myocardial infarction in patients under aorto-coronary bypass grafts with plasma level of myosin light chain I and 201Tl SPECT].

After aorto-coronary bypass grafts surgery plasma level of myosin light chain I, determined with monoclonal antibodies to myosin light chain I (LC-I), were studied in 12 patients (pts) without electrocardiographical perioperative myocardial infarction. Rest 201Tl myocardial images were collected before and after surgery. LC-I increased and reached peak levels (15 +/- 7 ng/ml) at 91 +/- 29 minutes after the aortic declamp. From peak levels LC-I rapidly decreased with fast half-time disappearance (1.4 +/- 0.9 hours). In 5 pts of 12 pts LC-I recovered to normal range and MB reached maximum levels (34 +/- 23 IU/L) at 18 +/- 9 hours after declamp. In 4 pts 201Tl images showed improvement and in one 201Tl images showed no changes. In 7 pts of 12 pts LC-I decreased to minimum levels (2.7 +/- 0.6 ng/ml) at 12 +/- 6 hours and then gradually increased to peak levels (5.6 +/- 0.9 ng/ml) on day 3 +/- 0.9. MB reached maximum level (61 +/- 20 IU/L) at 3.2 +/- 1 hours. In 201Tl images 3 pts showed suspected new lesion, 2 pts showed no changes and 2 pts showed improvement. No correlation was noted between peak LC-I level and duration of aortic declamp. No significant relation was suspected between early LC-I peak and irreversible myocardial cell injury. From close relationship between aortic declamp and appearance of LC-I peak, it was concluded that LC-I, accumulated during aortic clamp, was washed out by aortic declamp. Relation was suspected between early LC-I peak and myocardial injury during myocardial protection.(ABSTRACT TRUNCATED AT 250 WORDS)