THE RELATION OF CLINICAL OUTCOME TO DISSECTION AND THROMBUS FORMATIONDURING CORONARY ANGIOPLASTY

Background: Although the development of thrombus or dissection during percutaneous transluminal coronary angioplasty (PTCA) increases the ri sk of abrupt vessel closure, the magnitude of the effect is difficult to define. Objective: The aim of the study was to determine prospectiv ely the effect of the development of thrombus or dissection on PTCA pr ocedural outcome. Methods: Data from 591 consecutive angioplasty proce dures involving 756 lesions at 9 clinical centers were included in a p rospective registry with a core angiographic laboratory. Results: Clin ical success (defined as < 50% stenosis of all target lesions assessed in a core angiographic laboratory, with no major complications of dea th, Q wave or non-Q wave myocardial infarction or emergency CABG) was achieved in 497 patients (84%). Major complications occurred in 45 (7. 6%). Abrupt vessel closure, including both established closure (TIMI g rade 0 or I flow) and impending closure (> 50% stenosis, TIMI grade 0- 2 flow, plus use of additional interventions) occurred in 65 patients (11%). Angiographically visible dissections developed in 40% of lesion s; more severe grades of dissection were associated with reduced succe ss rates, and increased incidence of and abrupt vessel closure and maj or complication. Angiographic evidence of thrombus (filling defects) d eveloped in 12.3% of lesions; the presence of thrombus was associated with significantly lower procedural success (61% vs. 86%) and signific antly higher rates of abrupt vessel closure (28% vs 7%) and major comp lications (24% vs. 6%). With multivariable analysis, thrombus was iden tified as an independent predictor of procedural success, abrupt vesse l closure, and major complications. Conclusion: The development of sev ere dissections or thrombus following PTCA is associated with signific antly lower procedural success rates and higher rates of abrupt vessel closure and major complications. Patients who develop severe dissecti on or thrombus may be appropriate candidates for more aggressive forms of therapy.