THE RELATION OF CLINICAL OUTCOME TO DISSECTION AND THROMBUS FORMATION DURING CORONARY ANGIOPLASTY

Background: Although the development of thrombus or dissection during percutaneous transluminal coronary angioplasty (PTCA) increases the risk of abrupt vessel closure, the magnitude of the effect is difficult to define. Objective: The aim of the study was to determine prospectively the effect of the development of thrombus or dissection on PTCA procedural outcome. Methods: Data from 591 consecutive angioplasty procedures involving 756 lesions at 9 clinical centers were included in a prospective registry with a core angiographic laboratory. Results: Clinical success (defined as < 50% stenosis of all target lesions assessed in a core angiographic laboratory, with no major complications of death, 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 grade 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 lesions; more severe grades of dissection were associated with reduced success rates, and increased incidence of and abrupt vessel closure and major complication. Angiographic evidence of thrombus (filling defects) developed in 12.3% of lesions; the presence of thrombus was associated with significantly lower procedural success (61% vs. 86%) and significantly higher rates of abrupt vessel closure (28% vs 7%) and major complications (24% vs. 6%). With multivariable analysis, thrombus was identified as an independent predictor of procedural success, abrupt vessel closure, and major complications. Conclusion: The development of severe dissections or thrombus following PTCA is associated with significantly lower procedural success rates and higher rates of abrupt vessel closure and major complications. Patients who develop severe dissection or thrombus may be appropriate candidates for more aggressive forms of therapy.