Physiology-Guided Management of Serial/Diffuse Coronary Artery Disease.

PURPOSE OF REVIEW: Just over four decades ago, the management of coronary artery disease (CAD) witnessed a major breakthrough with the advent of minimally invasive treatment modalities like angioplasty followed by coronary stenting. Dr. Andreas Gruentzig pioneered this field in 1977 by adding a balloon to the Dotter catheter. From its inception, he was cognizant of the need for measuring pressures before and after balloon inflation in the treated coronary artery, device placement in the treated coronary artery. However, for decades subsequently, emphasis was placed primarily on preprocedural non-invasive tests and angiographic assessment of lesions based on percent diameter stenosis to guide therapeutic interventions. We review the progress of these physiologic advancements in management over the last 20 years, as well as the current state and prospects for the future. RECENT FINDINGS: More recently, clinical features heavily drive the decision whether or not to stent the diseased segment. A little more than two decades ago, a new approach to facilitate the decision whether or not to intervene on intermediate stenoses began to evolve. It became clear that other features besides angiography are important when considering benefit of mechanical intervention. The emphasis shifted to assessment of the physiological significance of coronary lesions, rather than solely anatomical identification of lesions at angiography. Physiological assessments have served to better discriminate potentially flow-limiting lesions, utilizing cutoff measurements to determine which patients would benefit from intervention in addition to medical therapy. We have found that there is still need for arrival at a consensus as regards the best practice in the context of physiological assessment of serial stenotic lesions, but that studies do show that techniques currently available are non-inferior to each other, and highly effective.

Ultrasound assessment of carotid arteries: Current concepts, methodologies, diagnostic criteria, and technological advancements.

Following cardiac disease and cancer, stroke continues to be the third leading cause of death and disability due to chronic disease in the developed world. Appropriate screening tools are integral to early detection and prevention of major cardiovascular events. In a carotid artery, the presence of increased intima-media thickness, plaque, or stenosis is associated with increased risk of a transient ischemic attack or a stroke. Carotid artery ultrasound remains a long-standing and reliable tool in the current armamentarium of diagnostic modalities used to assess vascular morbidity at an early stage. The procedure has, over the last two decades, undergone considerable upgrades in technology, approach, and utility. This review examines in detail the current state and usage of this integrally important means of extracranial cerebrovascular assessment.

Assessment of tricuspid valve by two- and three-dimensional echocardiography with special reference to percutaneous repair and prosthetic valve implantation procedures.

Moderate-to-severe tricuspid regurgitation affects approximately 1.6 million people in the United States. An estimated 8000 patients will undergo tricuspid surgery annually, leaving a large number of patients with this condition untreated. Many of these individuals who are not referred for surgery engender a large unmet clinical need; this may be primarily due to the surgical risk involved. In persons who are categorized as high-risk surgical candidates, percutaneous procedures present a viable alternative. The majority of developmental attention as regards percutaneous approaches has been focused on the aortic and mitral valves recently, but few data are available about the feasibility and efficacy of minimally invasive tricuspid valve treatment. We review the usefulness of two- and three-dimensional echocardiography in the assessment of the tricuspid valve with special reference to recent interest in percutaneous repair and prosthetic valve implantation procedures for severe functional tricuspid regurgitation.

Myocardial contrast echo: current status and future directions.

Contrast echocardiography has been around since the late 1960's. CE began with an M-mode observation by Joyner and a subsequent publication by Gramiak and Shah on enhanced echocardiographic imaging of saline in the aorta. MCE has come a long way from a diagnostic tool to include therapeutics in its armamentarium. It is an ingenious modality for assessment of MPI at the tissue level with special applications in vascular inflammation and drug delivery however, is limited by the technical difficulties with image acquisition and microbubble physics. Refining imaging software and newer advances in microbubble agents continue to revamp contrast echocardiography.

Detection of resting myocardial perfusion defects by SonoVue myocardial contrast echocardiography.

BACKGROUND: SonoVue is a new microbubble contrast agent containing sulfur hexafluoride. We assessed the efficacy of SonoVue myocardial contrast echocardiography (MCE) to detect resting perfusion abnormalities. METHODS: Nineteen adult patients with a wall motion abnormality in a screening echocardiogram were studied. Each patient received up to four bolus injections of 2.0 mL SonoVue (Bracco Diagnostics, Inc.) during echocardiographic examination using either B-mode(n = 12)or power Doppler(n = 7)imaging. Each patient also had SPECT nuclear perfusion imaging performed. Segmental assessment of myocardial perfusion from SonoVue MCE images were compared with corresponding SPECT nuclear images. RESULTS: Using B-mode imaging, the mean number of views obtained with a single SonoVue injection ranged from 1.4 to 1.9, with 2 or 3 injections required for a complete examination. Ninety-four percent of segments were scored as diagnostic. Agreement between B-mode and SPECT images was 72% for segments with a perfusion defect, 86% for normal perfusion, and 80% for segments with either perfusion defect or normal perfusion (all views combined). Using power Doppler imaging, the mean number of views obtained with a single SonoVue injection ranged from 1.0 to 1.3, with 2 to 4 injections required for a complete examination. Sixty-eight percent of segments were scored as diagnostic. Agreement between power Doppler and SPECT images was 67% for perfusion defects, 53% for segments with normal perfusion, and 59% for segments with either perfusion defect or normal perfusion (all views combined). CONCLUSIONS: SonoVue MCE has the potential to assess myocardial perfusion at rest. B-mode imaging was more accurate than power Doppler imaging when compared with SPECT nuclear imaging.

Delineation of intracardiac shunts using contrast echocardiography.

Contrast echocardiography is useful to visualize the endocardial borders of the left ventricle and improve the signal intensity of spectral Doppler signals. It can also help to define intracardiac flow dynamics in complex situations. We report 2 cases where contrast echocardiography improved the delineation of complex shunts and also provided new information not available by conventional echocardiography.

Methods of contrast administration for myocardial perfusion imaging: continuous infusion versus bolus injection.

The debate over the optimal contrast administration method involves many issues. This article discusses bolus versus infusion administration pertaining to myocardial perfusion imaging. Continuous infusion ensures efficient and optimal data capture during contrast studies and is preferred over bolus injection for both theoretical and practical reasons. Although bolus administration is easier, its relative disadvantages outweigh its usefulness in myocardial perfusion imaging.