Percutaneous coronary angioscopy and stents

ABSTRACT With the expanding array of therapies available for coronary intervention, the invasive cardiologist has many choicesfor treating a specific lesion in an individual patient. Certain types of lesions might respond more effectively with stents,particularly the rigid Palmaz-Schatz device. Thrombus and dissection immediately following stent placement are associatedwith early occlusion, and the interventionist must be able to assess their presence pre- and post—stenting. Angiography isdeficient in quantifying minimal disease and in defining lesion architecture and composition, as well as the plaque ruptureandthrombosis associated with unstable angina. It is also imprecise in detecting dissection and thrombus. Intravascularultrasound (IVUS) provides high-resolution images that delineate irregularities and other structures inside the lumen andwithin the vessel wall and surrounding tissues. Like angiography, IVUS has limited specificity for thrombus differentiation.Angioscopy is superior to angiography and IVUS in detecting thrombus and dissection. Angioscopy allows the clinician toassess the appearance of stent struts after deployment and at follow-up. This may aid in reducing acute complications as wellas restenosis. Follow-up angioscopy of stents to detect thrombus or exposed struts may guide therapy in a patient who hasclinical symptoms of restenosis.1. INTRODUCTIONWith the expanding array of therapies available for coronary intervention, the invasive cardiologist has many choicesfor treating a specific lesion in an individual patient. A variety of balloons, lasers, atherectomy devices, and endoprosthesescan now be matched to applicable pathology, making accurate lesion definition essential. The methods available for definingvascular pathology to guide in the selection of appropriate intervention include angiography, intravascular ultrasound, andangioscopy.Recent studies suggest that certain types of lesions might respond more effectively with sterns, particularly the rigidPalmaz-Schatz device. Intracoronary steffis were designed to improve the results of balloon dilation by preventing acutecomplications (such as dissection, intimal flaps, or lesion recoil) as well as reducing the incidence of restenosis. Thrombusand dissection immediately following stent placement are associated with early occlusion.1 Because these two factors have acritical role in determining the outcome of stent implantation, the interventionist must be able to assess their presence pre-and post-stenting.Angiography has been the traditional assessment tool. Unfortunately, this technique is deficient in quantifying minimaldisease and in defining lesion architecture and composition, as well as the plaque rupture and thrombosis associated withunstable angina. It is also imprecise in detecting dissection and thrombus.2'3Intravascular ultrasound (IVUS) provides high-resolution images that delineate irregularities and other structures insidethe lumen and within the vessel wall and surrounding tissues.4"'6 IVUS allows reproducible measurement of luminaldiameters and cross-sectional areas for baseline, post-treatment, and follow-up evaluation.7 However, this technology shareswith angiography a serious disadvantage: the limited specificity for thrombus differentiation.8Percutaneous intracoronary angioscopy has proved to be superior to both angiography and IVUS in detecting thrombusand dissection.8'9'1° Angioscopy also allows the clinician to assess the appearance of stent struts after deployment and atfollow-up.'1"2 This may aid in reducing acute complications as well as restenosis. Follow-up angioscopy of stents to detectthrombus or exposed struts may guide therapy in a patient who has clinical symptoms of restenosis.2. METHODSTo assess the usefulness of angioscopy in the procedural and follow-up evaluations of coronary stent deployment,patients were randomly selected from participants in two ongoing FDA-sponsored trials of the Palmaz-Schatz and the