Linda Norton

Incidental Findings on Cardiac Multidetector Row Computed Tomography Among Healthy Older Adults: Prevalence and Clinical Correlates

BACKGROUND With the widespread use of cardiac multidetector row computed tomography (MDCT), the issue of incidental findings is receiving increasing attention. Our objectives were to evaluate the prevalence of incidental findings discovered during cardiac MDCT scanning and to identify clinical variables associated with incidental findings. METHODS This cross-sectional analysis involved a population-based sample recruited from an integrated health care delivery system in Northern California as part of the Atherosclerotic Disease, Vascular Function and Genetic Epidemiology (ADVANCE) Study. Healthy men and women aged 60 to 69 years without diagnosed cardiovascular disease underwent cardiac MDCT for the detection and quantification of coronary artery calcification. The images were prospectively evaluated for incidental findings. RESULTS A total of 459 participants underwent MDCT scanning, and the overall prevalence of any incidental finding was 41%. Of the 459 participants, 105 (23%) had at least 1 incidental finding that was recommended for clinical or radiological follow-up examination, the most common of which was single or multiple pulmonary nodules (18%). Participants with and without incidental findings had comparable baseline demographics and selected clinical variables, although there were significantly fewer men and a significantly lower prevalence of the metabolic syndrome in those with incidental findings. CONCLUSIONS Incidental findings, especially pulmonary nodules, are common in cardiac MDCT performed to assess coronary artery calcification in older healthy adults. The net risks and benefits of looking for noncardiac abnormalities during cardiac MDCT should be rigorously evaluated.

Ankle brachial index screening in asymptomatic older adults

BACKGROUND Screening for peripheral arterial disease (PAD) by measuring ankle brachial index (ABI) in asymptomatic older adults is currently recommended to improve cardiovascular disease risk assessment and establish early treatment, but it is not clear if the strategy is useful in all populations. We examined the prevalence and independent predictors of an abnormal ABI (<0.90), in an asymptomatic sample of 1,017 adults, 60 to 69 years old, enrolled in the ADVANCE study. METHODS Baseline data collected between December 2001 and January 2004 among the healthy older controls enrolled in ADVANCE was examined. Frequency distributions and prevalence estimates of an abnormal ABI were calculated, using both standard and modified definitions of ABI. Stepwise logistic regression was used to examine independent predictors of ABI <0.90. Signal detection analysis using recursive partitioning was employed to explore potential demographic and clinical variables related to ABI <0.90. RESULTS The prevalence of ABI <0.90 was 2% when using the standard definition and 5% when using a modified definition. ABI prevalence did not differ by gender (P > .05). Compared with subjects who had a normal ABI (0.90-1.39), subjects with an ABI <0.90 were more likely to currently smoke, be physically inactive, have a coronary artery calcium score >10, and an FRS >20% (P ≤ .02). Independent predictors of ABI <0.90 when using the standard definition included currently smoking, physical inactivity, and body mass index >30 (all P values ≤.03), and when using the modified definition included currently smoking, physical inactivity, and hypertension (all P values ≤.04). Currently, smoking was the only significant variable for ABI <0.90 derived through recursive partitioning (P = .02), and indicated that prevalence of ABI <0.90 was 1.5% for nonsmokers, while it was 6.6% for current smokers. CONCLUSIONS ABI screening in generally healthy individuals 60 to 69 years old may result in lower prevalence rates of a positive result than estimates based on studies in clinical populations. The modified definition for calculating ABI captured more asymptomatic adults with suspected peripheral arterial disease. More evaluation of the appropriate role of ABI screening in unselected populations is needed before routine screening is implemented.

Clinical utility of the stanford brief activity survey in men and women with early-onset coronary artery disease

PURPOSE: To determine the utility of the Stanford Brief Activity Survey (SBAS) as a quick screening tool in a clinical population, where no other measure of physical activity was available. METHODS: The SBAS was administered to 500 younger cases in the Atherosclerotic Disease Vascular Function and Genetic Epidemiology (ADVANCE) study, a case-control genetic association study, between December 2001 and January 2004. Younger cases in the ADVANCE study included men (<46 years old) and women (<56 years old) diagnosed with early-onset coronary artery disease. Frequency distributions of the SBAS and associations between SBAS activity categories and selected cardiovascular disease risk factors by sex were calculated. RESULTS: Subjects were 45.9 ± 6.4 years old, 68% married, 61% women, 51% white, and 21% college graduates. Clinical diagnoses for early-onset coronary artery disease included 61% myocardial infarction, 23% coronary revascularization procedure, and 16% angina pectoris. In women, associations between all cardiovascular disease risk factors examined across SBAS categories were statistically significant (P trend < .01). In men, the associations across SBAS categories were statistically significant (P trend < .01), except for body mass index (P trend = .065). Adjustment for body mass index, age, ethnicity, and education with interactions by sex did not change the results. CONCLUSION: Subjects in the higher SBAS activity categories had more favorable cardiovascular disease risk profiles than did their less active counterparts, regardless of sex. The SBAS can be recommended for use in clinical populations providing immediate feedback on current physical activity level.

Stereotactic Ablative Radiotherapy for the Treatment of Refractory Cardiac Ventricular Arrhythmia

A 71-year-old man with coronary artery disease, coronary artery bypass grafting in 2000, baseline ejection fraction of 0.24, and implantation of a single chamber implanted cardioverter defibrillator (ICD) in 2009 for ventricular tachycardia (VT) presented with continuous episodes of nonsustained and sustained VT refractory to sotalol and mexiletine. Despite angioplasty and stent for coronary artery disease, VT continued for 2 years. Medical history included atrial fibrillation and oxygen-dependent chronic obstructive pulmonary disease. Baseline electrocardiogram (ECG) showed atrial fibrillation with a ventricular rate of 82 beats per minute with inferior Q waves and QRS duration of 90 ms. Twelve-lead ECG during VT showed a regular, wide-complex tachycardia at 160 beats per minute (CL 380–400 ms), with a right bundle branch block pattern, superior axis, precordial transition at V3–V4. His ICD log showed numerous VT episodes, with a single morphology seen on intracardiac ventricular electrogram, cycle length 380–411ms. Episodes were nonsustained, pace-terminated, and shock-terminated. As catheter ablation was relatively medically contraindicated, he consented to a Food and Drug Administration and Institutional Review Board–approved compassionate-use protocol of stereotactic arrhythmia radioablation (STAR), noninvasive ablation of VT substrate by stereotactic ablative radiotherapy (SABR) techniques for tumors. STAR therapy was delivered in October, 2012. Baseline echocardiogram showed a dilated left ventricle (LV), ejection fraction of 0.24, with basal inferior aneurysm, and apical and infero-posterior akinesis. Positron emission tomography–computed tomography showed extensive hypometabolic scar in the LV extending between the LV base and the apex, involving the inferior, inferoseptal, and inferolateral walls. A target for STAR was delineated using proprietary visualization and contouring software (CardioPlan™, CyberHeart™, Portola Valley, CA), outlining the target volume corresponding to what would have been the …

A histological and mechanical analysis of the cardiac lead-tissue interface: implications for lead extraction.

The major risks of pacemaker and implantable cardioverter defibrillator extraction are attributable to the fibrotic tissue that encases them in situ, yet little is known about the cellular and functional properties of this response. In the present research, we performed a histological and mechanical analysis of human tissue collected from the lead-tissue interface to better understand this process and provide insights for the improvement of lead design and extraction. The lead-tissue interface consisted of a thin cellular layer underlying a smooth, acellular surface, followed by a circumferentially organized collagen-rich matrix. 51.8±4.9% of cells were myofibroblasts via immunohistochemistry, with these cells displaying a similar circumferential organization. Upon mechanical testing, samples exhibited a triphasic force-displacement response consisting of a toe region during initial tensioning, a linear elastic region and a yield and failure region. Mean fracture load was 5.6±2.1N, and mean circumferential stress at failure was 9.5±4.1MPa. While the low cellularity and fibrotic composition of tissue observed herein is consistent with a foreign body reaction to an implanted material, the significant myofibroblast response provides a mechanical explanation for the contractile forces complicating extractions. Moreover, the tensile properties of this tissue suggest the feasibility of circumferential mechanical tissue disruption, similar to balloon angioplasty devices, as a novel approach to assist with lead extraction.

Phlebitis in Amiodarone Administration: Incidence, Contributing Factors, and Clinical Implications

BACKGROUND Intravenous amiodarone is an important treatment for arrhythmias, but peripheral infusion is associated with direct irritation of vessel walls and phlebitis rates of 8% to 55%. Objectives To determine the incidence and factors contributing to the development of amiodarone-induced phlebitis in the coronary care unit in an academic medical center and to refine the current practice protocol. METHODS Medical records from all adult patients during an 18-month period who received intravenous amiodarone while in the critical care unit were reviewed retrospectively. Route of administration, location, concentration, and duration of amiodarone therapy and factors associated with occurrence of phlebitis were examined. Descriptive statistics and regression methods were used to identify incidence and phlebitis factors. RESULTS In the final sample of 105 patients, incidence of phlebitis was 40%, with a 50% recurrence rate. All cases of phlebitis occurred in patients given a total dose of 3 g via a peripheral catheter, and one-quarter of these cases (n = 10) developed at dosages less than 1 g. Pain, redness, and warmth were the most common indications of phlebitis. Total dosage given via a peripheral catheter, duration of infusion, and number of catheters were significantly associated with phlebitis. CONCLUSIONS Amiodarone-induced phlebitis occurred in 40% of this sample at higher drug dosages. A new practice protocol resulted from this study. An outcome study is in progress.