MECHANISM OF HIGH-SPEED ROTATIONAL ATHERECTOMY AND ADJUNCTIVE BALLOONANGIOPLASTY REVISITED BY QUANTITATIVE CORONARY ANGIOGRAPHY - EDGE-DETECTION VERSUS VIDEODENSITOMETRY

High-speed rotational coronary atherectomy (RA) is primarily used to t reat complex lesions. Quantitative angiographic analysis of such compl ex lesions by edge detection is often unsuitable, whereas videodensito metry, measuring vessel dimensions independently of the target stenosi s contours, may offer potential advantages. To gain insight into the o perative mechanism of HA and to study the agreement between the two qu antitative angiographic methods in measuring the minimal luminal cross -sectional area, the edge detection and videodensitometry techniques w ere applied to coronary angiograms of 21 lesions in 19 patients with s ymptoms who underwent successful HA and balloon angioplasty (BA). Obst ruction diameter as determined by edge detection increased from 1.00 /- 0.31 mm before intervention to 1.35 +/- 0.29 mm after HA (p < 0.001 ) and further increased to 1.74 +/- 0.33 mm after adjunctive BA (p < 0 .001). The mean between-method difference (edge detection minus videod ensitometry) was 0.34 mm(2) before intervention, 0.13 mm(2) after HA, and 0.09 mm(2) after adjunctive HA (not significant). The standard dev iation of the differences decreased from +/- 0.87 mm(2) before interve ntion to +/- 0.80 mm(2) after HA (not significant) and increased after BA significantly to +/- 1.21 mm(2) (p < 0.05). Thus edge detection an d videodensitometry provided equivalent Immediate angiographic results after HA and adjunctive BA. The good agreement after RA may reflect t he operative mechanism of RA, which by ablation of noncompliant plaque material yields a circular symmetric lumen with smooth surface. The i ncreased dispersion of the between-method differences observed after a djunctive HA presumably results from dissections, plaque ruptures, and loss of luminal smoothness after balloon dilatation.