Quantitative Coronary Dimensions and Restenosis after Directional Atherectomy or Balloon Angioplasty

Coronary artery dimensions were evaluated in 42 patients (52 lesions) undergoing directional atherectomy of primary atheromatous lesions in native coronary arteries between October 1989 and April 1991. Dimensions were compared with a cohort of 162 patients (213 lesions) undergoing percutaneous transluminal coronary angioplasty of similar lesions between March 1984 and April 1988. Computer-assisted quantitative angiography was performed for paired near-orthogonal views (captured during diastole) of each treated lesion; image pairs taken prior to, immediately following, and 6 months after coronary intervention were studied. Although coronary dimensions were equivalent for the two treatment groups before therapy, the immediate posttreatment minimal lumen diameter was significantly larger after atherectomy than angioplasty (2.24 ± 0.53 mm vs 1.52 ± 0.34 mm, P < 0.01). Despite this, coronary dimensions were similar in the two groups at follow-up angiography. Several dichotomous definitions of restenosis were tested using these quantitative data. Restenosis rates were similar for the two treatments using most definitions, but those definitions based on loss of relative or absolute lumen dimensions resulted in higher rates of restenosis following atherectomy. These data demonstrate that: (1) directional coronary atherectomy can achieve greater initial gain in luminal dimensions than angioplasty; (2) the loss in vessel dimensions within 6 months (late loss) is greater after atherectomy than after angioplasty; and (3) restenosis definitions rely on relative or absolute loss of initial luminal gain favor of angioplasty.