The video explores results obtained with deployment of intracoronary stents with the use of intravascular ultrasound imaging.   Intravascular ultrasound (IVUS) is a medical imaging methodology using a specially designed catheter with a miniaturized ultrasound probe attached to the distal end of the catheter and the proximal end of the catheter is attached to a computer to generate an image from the ultrasound reflections.  The images are comparable to a low power histologic cross section of human arteries.  IVUS provides insight into cases to understand the pathophysiologic mechanism of subacute stent thrombosis following stent insertion. The information provided by ultrasound imaging led to the use of larger balloons and higher-pressure inflations, which were documented by ultrasound to enlarge the lumen area.   Intravascular ultrasound imaging has been helpful in altering therapy, e.g., reinflating  with higher pressure,  using a larger balloon, redilating proximally or distally in the stent, revealing a stenosis that is unrecognized or underappreciated by angiography , or demonstrating that further intervention is not necessary.  These observations led to a lower level of complications following placement of coronary stents, which paved the way for the generalized application of stenting for treatment of coronary artery disease.

Volume I  (1:26:58)  MPG4  3.6 Gb  (1996)

Intravascular ultrasound (IVUS) is a valuable adjunct to angiography, providing new insights in the diagnosis and therapy of coronary disease. Angiography depicts only a 2D silhouette of the lumen, whereas IVUS allows tomographic assessment of lumen area, plaque size, distribution, and composition. The safety of IVUS is well documented, and the assessment of luminal dimensions represents an important application of this modality. Comparative studies show the greatest disparities between angiography and ultrasound after mechanical interventions. In young subjects, normal intimal thickness is typically ≈0.15 mm. With IVUS, lipid-laden lesions appear hypoechoic, fibromuscular lesions generate low-intensity echoes, and fibrous or calcified tissues are echogenic. Calcium reflects ultrasound effectively and obscures the underlying peripheral wall (acoustic shadowing). The extent and severity of disease by angiography and ultrasound are frequently discrepant. Arterial remodeling refers to changes in vascular dimensions during the development of atherosclerosis. At diseased sites, the external elastic membrane may actually shrink in size, contributing to luminal stenosis.  This is referred to as negative remodeling. The interpretation of IVUS relies on simple visual inspection of acoustic reflections to determine plaque composition. However, different tissue components may look similar, and artifacts may adversely affect ultrasound images. IVUS commonly detects occult disease in angiographically “normal” sites. In ambiguous lesions, ultrasound permits lesion quantification, particularly for left main coronary disease. IVUS has emerged as the optimal method for the detection of transplant vasculopathy. An important potential application of ultrasound is the identification of atheromas at risk of rupture. The mechanisms of action of interventional devices have been elucidated using IVUS. Ultrasound imaging is used by some operators to select the most suitable interventional device. IVUS-derived residual plaque burden is the most useful predictor of clinical outcome. In restenosis after balloon angioplasty, neo-intimal growth and negative remodeling are major mechanisms of late lumen loss. Although IVUS is not routinely used for stent optimization, the understanding of how to improve stent deployment based on IVUS insights, have dramatically altered interventional cardiology. New and emerging applications for IVUS are continuing to evolve, particularly in atherosclerosis regression-progression trials.   

Volume II  (1:13:02)  MPG4  3.4 Gb  (1996)

The management of intermediate coronary lesions, defined by an angiographic diameter stenosis of 40% to 70%, continues to be a therapeutic dilemma for cardiologists. The 2-dimensional representation of the arterial lesion provided by angiography is limited in distinguishing intermediate lesions that require stenting from those that simply need appropriate medical therapy. In the era of drug-eluting stents, some might propose that stenting all intermediate coronary lesions is an appropriate solution. However, the possibility of procedural complications such as coronary dissection, no reflow phenomenon, in-stent restenosis, and stent thrombosis requires accurate stratification of patients with intermediate coronary lesions to appropriate therapy. Intravascular ultrasound (IVUS) and fractional flow reserve index (FFR) provide anatomic and functional information that can be used in the catheterization laboratory to designate patients to the most appropriate therapy. The purpose of this video is to discuss the critical information obtained from IVUS and FFR in guiding treatment of patients with intermediate coronary lesions. In addition, the importance of IVUS and FFR in the management of patients with serial stenoses, bifurcation lesions, left main disease, saphenous vein graft disease, and acute coronary syndrome are discussed.

Volume III  (1:22:38)  MPG4  3.82 Gb  (1996)

Background

Methods and results

Conclusions