ANGIOGRAPHIC, ULTRASONIC, AND ANGIOSCOPIC ASSESSMENT OF THE CORONARY-ARTERY WALL AND LUMEN AREA CONFIGURATION AFTER DIRECTIONAL ATHERECTOMY- THE MECHANISM REVISITED

The purpose of the present study was to use the complementary informat ion of angiography, intravascular ultrasound, and intracoronary angios copy before and after directional atherectomy to characterize the post atherectomy appearance of vessel wall contours and the mechanism of lu men enlargement. Directional coronary atherectomy aims at debulking ra ther than dilating a coronary artery lesion. The selective removal of the plaque may potentially minimize the vessel wall damage and lead to subsequent better late outcome. Whether plaque removal is the main me chanism of action has only to be assessed indirectly by angiography an d warrants further investigation with detailed analysis of luminal cha nges and vessel wall damage by ultrasound and direct visualization wit h angioscopy. Twenty-six patients have been investigated by quantitati ve angiography, intravascular ultrasound, and intracoronary angioscopy (n = 19) before and after atherectomy. In addition, all retrieved spe cimens were microscopically examined. Ultrasound imaging showed an inc rease in lumen area from 1.95 +/- 0.70 mm(2) to 7.86 +/- 2.16 mm(2) at atherectomy. The achieved gain mainly resulted from plaque removal be cause plaque plus media area decreased from 18.16 +/- 4.47 mm(2) to 13 .13 +/- 3.10 mm(2). Vessel wall stretching (i.e., change in external e lastic lamina area) accounted for only 15% of lumen area gain. Luminal gain was higher in noncalcified (6.52 +/- 2.12 mm(2)) lesions than in lesions containing deeply located calcium(5.19 +/- 0.99 mm(2)) and lo west in superficially calcified lesions (5.41 +/- 2.41 mm(2)). Ultraso und imaging identified an atherectomy byte in 85% of the cases, wherea s angioscopy revealed such a crevice in 74%. The complementary use of the three techniques revealed an underestimation of the presence of di ssection/tear and new thrombus by angiography (10% and 4%) and ultraso und imaging (12% and 0%) compared with angioscopy (26% and 21%). The c ombined use of angiography, ultrasound, and angioscopy reveals that th e postatherectomy luminal lining is not as regular and smooth as that seen by angiography. Luminal enlargement with atherectomy is achieved by plaque excision rather than arterial expansion.