BENEFIT OF INTRACORONARY ULTRASOUND IN THE DEPLOYMENT OF PALMAZ-SCHATZ STENTS

Objectives. This study was designed to evaluate the changes in intrast ent and angiographic dimensions when intravascular ul trasound imaging is used to direct the deployment of balloon-expandable Palmaz-Schatz stents in coronary arteries and saphenous vein grafts. Background. Int ravascular ultrasound provides more information than angiography in th e imaging of intravascular structures. Previous studies have shown tha t obtaining a larger lumen (greater ''acute gain'') with coronary inte rventions such as stenting leads to less restenosis and subacute throm bosis. It is not clear whether the information obtained by intravascul ar ultrasound can be used to obtain a greater acute gain in lumen dime nsions. Methods. Forty consecutive patients undergoing Palmaz-Schatz s tent implantation had intravascular ultrasound imaging performed after a good angiographic appearance was obtained. If the stent did not app ear adequately expanded by intravascular ultra sound, or if the struts were poorly apposed to the arterial wall, further stent dilation with larger balloons or higher pressure inflations were performed. Twenty nine patients had subsequent intravascular ultrasound imaging. Intrast ent diameters and areas were compared from the initial to the final in travascular ultra sound studies. Results. Of the 40 patients studied, only 5 (13%) had an adequate result by intravascular ultrasound despit e an acceptable angiographic appearance in all patients. Six additiona l patients did not undergo subsequent intravascular ultrasound imaging . The other 29 patients all demonstrated a significant increase in int rastent minimal diameter (mean 19%), major diameter (11%) and cross-se ctional area (34%) (p < 0.001 for all measurements). Conclusions. The use of intravascular ultrasound imaging in the deployment of balloon e xpandable Palmaz-Schatz stents leads to a significant increase in intr astent dimensions (greater ''acute gain'').