Multivariate predictors of intravascular ultrasound end points after directional coronary atherectomy

Objectives. This study attempted to identify the clinical, angiographic, procedural and intravascular ultrasound predictors of directional atherectomy results assessed by intravascular ultrasound.Background. Several angiographic and intravascular ultrasound variables have been associated with the outcome of directional coronary atherectomy. No study has incorporated both modalities into a predictive model.Methods. One hundred seventy patients were analyzed using preintervention and postintervention intravascular ultrasound and quantitative angiography. Clinical and procedural variables were collected by independent chart review. Quantitative and qualitative angiographic analysis was performed by a core laboratory in blinded manner. Intravascular ultrasound was performed using a transducer-tipped catheter, rotating within a stationary imaging sheath, and withdrawn automatically at 0.5 mm/s. Clinical, procedural, angiographic and ultrasound variables were tested iin a multivariate linear regression model. Dependent ultrasound variables included postatherectomy lumen cross-sectional area and percent cross-sectional narrowing (plaque plus media/external elastic membrane cross-sectional area) and, in a subgroup of 47 patients studied using volumetric analysis, percent plaque volume removal.Results. By multivariate stepwise linear regression analysis, predictors of residual lumen cross-sectional area (correcting for reference lumen area) included arc of calcium and preatherectomy plaque plus media cross-sectional area; predictors of residual cross-sectional narrowing were arc of calcium, preatherectomy plaque plus media cross-sectional area and lesion length; and predictors of percent plaque volume removal were arc of calcium and atherectomy device size.Conclusions. The preintervention lesion arc of calcium measured by intravascular ultrasound is the most consistent predictor of the effectiveness and results of directional coronary atherectomy.