Imaging assessment of cardiovascular risk in asymptomatic adults.

OBJECTIVE: This article will address the role of coronary artery calcium (CAC) and carotid intima-media thickness screening in asymptomatic at-risk adults and the broader concept of vulnerable plaque as it applies to this population. CONCLUSION: Imaging for assessment of cardiovascular risk in asymptomatic adults has been the subject of considerable interest and some controversy. The incorporation of CAC and carotid intima-media thickness assessment into recent guidelines reflects the growing evidence base for these applications.

Percutaneous salvage of thrombosed immature arteriovenous fistulas.

Thrombosed immature fistulas have historically been considered unsalvageable. However, advances in procedure and balloon catheter technologies have expanded the scope of endovascular treatments. This study investigates the efficacy, functionality, and cost associated with the use of percutaneous techniques for the salvage of thrombosed immature fistulas. Over a 2-year period and from a population of 18,000 patients on hemodialysis, 140 consecutive patients with thrombosed immature fistulas underwent attempts at salvage via thrombectomy procedures. All fistulas had thrombosed following access creation and had never been used for hemodialysis. Multiple approaches were utilized to gain access to the fistula, including trans-fistula cannulation, distal arterial puncture, and proximal retrograde venous access. Thrombectomy was performed via balloon maceration and aspiration. Accelerated maturation was achieved through sequential angioplasty of diffusely stenotic veins and elimination of competing branch vessels. Primary access, primary assisted, and secondary access patencies were calculated at 3, 6, 12, and 24 months. A cost analysis was performed based on procedure statistics and the 2009 Medicare reimbursement schedule and compared with data from the 2009 United States Renal Data Survey. Thrombectomy was successful in 119 (85%) immature clotted fistulas, and hemodialysis adequacy was achieved in 111 (79%) fistulas. The average maturation time from thrombectomy to cannulation for dialysis was 46.4 days, with an average of 2.64 interventions per patient. There were 5 (3.5%) cases of angioplasty-induced rupture, all of which were treated with stent placement. Clinically significant pseudoaneurysm formation occurred in 4 (2.8%) patients. At 12 months, secondary access patency of salvaged accesses was 90%. Based on 2009 Medicare outpatient billing rates per patient per initial access-year and the maturation times observed in the New York area, percutaneous salvage of thrombosed immature fistulas costs $4881 to $14,998 less than access abandonment and new access creation. Endovascular techniques can be used for the salvage of thrombosed nonmaturing fistulas. When analyzed within the initial access-year, this approach yields significant cost savings over access abandonment.

An Unusual Case of Hashimoto's Thyroiditis Presenting as Impending Cardiac Tamponade in a Patient with Acquired Immune Deficiency Syndrome (AIDS).

BACKGROUND Cardiac tamponade is a life-threatening pericardial compressive disorder that is a common downstream manifestation of infections, malignancy, and metabolic disorders. Hypothyroidism is a rare cause of tamponade that is attributed to the slow accumulation of effusive fluid into the intrapericardial space. In individuals living with HIV/AIDS, tamponade is commonly associated with infection or malignancy. To our knowledge, this is the first reported case of a patient with HIV/AIDS to have been identified with tamponade secondary to hypothyroidism. CASE REPORT Herein, we describe the case of a 52-year-old male patient with a history of AIDS, who presented with nausea, vomiting, diarrhea, and episodic gastrointestinal discomfort for the past several weeks, in conjunction with progressive fatigue. At initial presentation, he had no hemodynamic or clinical signs of tamponade, but pericardial effusion was incidentally found on imaging. Further investigations revealed an undiagnosed Hashimoto's thyroiditis as a function of restored immunocompetency, which ultimately led to the impending tamponade in this patient. We describe his clinical course through diagnosis of autoimmune hypothyroidism, review cardiac tamponade and hypothyroidism in the context of people living with HIV/AIDS, and discuss this rare manifestation of restored immunocompetency. CONCLUSIONS Hypothyroidism should be ruled out in all patients presenting with pericardial effusions or cardiac tamponade, even in people living with HIV/AIDS or those with a history of immune deficiencies.

Challenges and management of high-flow arteriovenous fistulae.

The Kidney Dialysis Outcomes Quality Initiative and Fistula First Initiative have embraced the arteriovenous fistula as the gold standard for hemodialysis accesses. Despite this status, fistulae are fraught with complex issues ranging from a high primary failure rate to high flow resulting in increased cardiovascular morbidity. It is important not to overlook the insidious peril of a hyperfunctioning access that may actively promote cardiac overload, cardiopulmonary recirculation, rapid access growth with aneurysm enlargement, recurrent venous stenosis resulting in access failure, and inflow/outflow mismatch. Once recognized, flow can and should be reduced to mitigate these and other negative effects.

Sharp needle recanalization for salvaging hemodialysis accesses with chronically occluded peripheral outflow.

PURPOSE: To assess the effectiveness of sharp needle recanalization (SNR) for treatment of chronically occluded venous outflow in hemodialysis access. METHODS: A retrospective analysis of patient records from January 2006 to March 2010 was conducted. Forty-four hemodialysis patients (31 fistulas, 13 grafts) were referred for arm swelling (18%), excessive bleeding after dialysis (29%), and thrombosis (53%). All patients had chronic occlusion of the outflow vein which failed conventional recanalization techniques. A new outflow pathway was established by advancing a 21g needle and dilating the subcutaneous tract to bridge the fistula body to a juxtaposed patent vein. If necessary, uncovered or covered stents were utilized to maintain patency of the newly formed subcutaneous tract. RESULTS: Forty-four patients underwent 45 SNR procedures, with restoration of normal function and complete relief of symptoms in 40 (91%) patients. The average tract length was 15 mm (range, 1 to 32) and the average dilatation diameter was 8 mm. During the initial SNR procedure, bare metal (n=21) or covered (n=5) stents were inserted in 26 patients. The average follow-up was 18.4 months (range, 0.2 to 48 months). No major complications were observed with the procedure. At 12 months, the primary access, primary tract, and secondary access patencies were 10%, 51%, and 92%, respectively. Percutaneous thrombectomy procedures were performed at a rate of 1.16 per access-year and the number of interventions within the tract was 0.94 per access-year. CONCLUSIONS: Sharp needle recanalization is an effective percutaneous treatment for restoring function to hemodialysis accesses with chronically occluded venous outflow pathways.

Imaging of subclinical atherosclerosis: questions and answers.

An increasingly important public health issue is the identification, stratification, and optimal management of individuals with subclinical atherosclerosis. This review addresses those aspects of noninvasive imaging of subclinical atherosclerosis that are most available and relevant to the practicing radiologist.

Prognostic value of quantitative stress myocardial perfusion imaging in unstable angina patients with negative cardiac enzymes and no new ischemic ECG changes.

BACKGROUND: Limited data are available on the value of quantitative stress myocardial perfusion imaging (MPI) in patients with unstable angina. In this report we sought to study the long-term prognostic value of quantitative stress MPI in patients hospitalized with unstable angina with no new ischemic electrocardiographic changes and negative cardiac enzymes. METHODS AND RESULTS: The study population consisted of 136 patients who were hospitalized at the Methodist Hospital, Houston, Tex, with unstable angina and subsequently underwent MPI before discharge. Cox proportional hazards (regression) analysis was performed to identify clinical and MPI predictors of hard cardiac events (death or nonfatal myocardial infarction). During a mean follow-up of 31 +/- 17 months, 20 patients (15%) sustained either cardiac death (n = 12) or nonfatal myocardial infarction (n = 8). The significant multivariate predictors of cardiac events were the total perfusion defect size ( P = .002), the presence of reversible perfusion defects ( P = .01), and the presence of multiple perfusion defects ( P = .03). The perfusion defect size was significantly larger in patients with events than in those without events (21% +/- 20% vs 12% +/- 14%, P = .002). Kaplan-Meier analysis showed that cardiac events were much more likely to develop in patients with defects involving 15% or more of the left ventricle than in those with defects involving less than 15% of the left ventricle ( P = .003). CONCLUSIONS: In patients hospitalized with unstable angina with no new ischemic electrocardiographic changes and negative cardiac enzymes, quantitative stress MPI provides powerful prognostic information that can be used in the risk stratification of these patients.