Histopathology of coronary lesions with early loss of minimal luminal diameter after successful percutaneous transluminal coronary angioplasty: Is thrombus a significant contributor?, ,

Background Early loss of minimal luminal diameter of >0.3 mm after successful percutaneous transluminal coronary angioplasty (PTCA) is associated with a higher incidence of restenosis. The underlying mechanism of this early loss is unknown and thrombus may be a contributing factor. Methods We performed a prospective study using quantitative computerized planimetry on coronary tissue specimens obtained by directional coronary atherectomy of 24 lesions in which early loss occurred 22 ± 9 minutes after successful PTCA. Results Thrombus was present in 9 (37%) of 24 coronary specimens. Segmental areas (mm2 ) and percentage of total area were distributed as follows: sclerotic tissue, 4.07 ± 0.7 mm2 (63% ± 6%); fibrocellular tissue, 0.97 ± 0.27 mm2 (16% ± 4%); hypercellular tissue, 0.99 ± 0.29 mm2 (12% ± 3%); atheromatous gruel, 0.18 ± 0.07 mm2 (3% ± 0.1%); and thrombus, 0.24 ± 0.15 mm2 (6% ± 0.4%). There was no difference in the relative early loss index between lesions with or without thrombus (35% ± 7% vs 26% ± 2%, respectively; P = .87). Multiple stepwise regression analysis did not identify any histologic predictors of relative early loss index. Conclusion Histopathologic analysis of coronary lesions with early loss after successful PTCA suggests that thrombus may not play a significant role in this angiographic phenomenon. (Am Heart J 1998;136:804-11.)