James D. Myles

Contrast Material–induced Nephrotoxicity and Intravenous Low-Osmolality Iodinated Contrast Material: Risk Stratification by Using Estimated Glomerular Filtration Rate

PURPOSE To determine the effect of intravenous (IV) low-osmolality iodinated contrast material (LOCM) on the development of post-computed tomography (CT) acute kidney injury (AKI), stratified by pre-CT estimated glomerular filtration rate (eGFR), in patients with stable renal function. MATERIALS AND METHODS Institutional review board approval was obtained and patient consent waived for this HIPAA-compliant, retrospective study. CT examinations performed over a 10-year period on unique adult inpatients with sufficient serum creatinine (SCr) data and stable renal function (difference between baseline and pre-CT SCr within 0.3 mg/dL and 50% of baseline) were identified. A 1:1 propensity score matched cohort analysis with multivariate analysis of effects was performed with post-CT AKI as the primary outcome measure (8826 nonenhanced and 8826 IV contrast agent-enhanced CT studies in 17 652 patients). Propensity matching was performed with respect to likelihood of receiving IV contrast material (19 tested covariates). Post-CT AKI with Acute Kidney Injury Network SCr criteria was the primary endpoint. A stepwise multivariate conditional logistic regression model was performed to identify the effect of IV LOCM on post-CT AKI. RESULTS After 1:1 propensity matching, IV LOCM had a significant effect on the development of post-CT AKI (P = .04). This risk increased with decreases in pre-CT eGFR (≥ 60 mL/min/1.73 m(2): odds ratio, 1.00; 95% confidence interval: 0.86, 1.16; 45-59 mL/min/1.73 m(2): odds ratio, 1.06; 95% confidence interval: 0.82, 1.38; 30-44 mL/min/1.73 m(2): odds ratio, 1.40; 95% confidence interval: 1.00, 1.97; <30 mL/min/1.73 m(2): odds ratio, 2.96; 95% confidence interval: 1.22, 7.17). CONCLUSION IV LOCM is a nephrotoxic risk factor in patients with a stable eGFR less than 30 mL/min/1.73 m(2), with a trend toward significance at 30-44 mL/min/1.73 m(2). IV LOCM does not appear to be a nephrotoxic risk factor in patients with a pre-CT eGFR of 45 mL/min/1.73 m(2) or greater.

Prevalence and Predictors of Complications of Radiofrequency Catheter Ablation for Atrial Fibrillation

Complications of Atrial Fibrillation Ablation. Introduction: Up to 6% of patients experience complications after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF). The purpose of this study is to determine the prevalence and predictors of periprocedural complications after RFA for AF.

A critical decrease in dominant frequency and clinical outcome after catheter ablation of persistent atrial fibrillation

BACKGROUND Termination of persistent atrial fibrillation (AF) by radiofrequency ablation (RFA) is associated with a high probability of freedom from AF but requires extensive ablation and long procedure times. OBJECTIVE The purpose of this study was to determine whether a critical decrease in the dominant frequency (DF) of AF is a sufficient endpoint for RFA of persistent AF. METHODS Antral pulmonary vein isolation (APVI) followed by RFA of complex fractionated atrial electrograms (CFAEs) in the atria and coronary sinus was performed in 100 consecutive patients with persistent AF. The DF of AF in lead V1 and in the coronary sinus was determined by fast Fourier transform (FFT) analysis at baseline and before termination of AF to identify a critical decrease in DF predictive of sinus rhythm after RFA. RESULTS A > or =11% decrease in DF had the highest accuracy in predicting freedom from atrial arrhythmias, with a sensitivity of 0.71 and a specificity of 0.82 (P <.001). At a mean follow-up of 14 +/- 3 months after one ablation procedure, sinus rhythm was maintained off antiarrhythmic drugs in 8/35 (23%) and 20/26 (77%) of patients with a <11% and > or =11% decrease in DF, respectively (P <.001). Sinus rhythm was maintained in 24/39 patients (62%) in whom RFA terminated AF. The duration of RFA and total procedure time were longer in patients with AF termination (95 +/- 23 and 358 +/- 87 minutes) than in patients with a <11% decrease in the DF (77 +/- 16 and 293 +/- 70 minutes) or > or =11% decrease in DF (80 +/- 17 and 289 +/- 73 minutes), respectively (P <.01). Among the variables of age, gender, left atrial diameter, duration of AF, left ventricular ejection fraction, duration of RFA, a > or =11% decrease in DF, and termination of AF, a > or =11% decrease in DF (odds ratio = 9.89, 95% confidence interval [CI] 2.84-34.47) and termination during RFA (OR = 4.38, 95% CI 1.50-12.80) were the only independent predictors of freedom from recurrent atrial arrhythmias. CONCLUSION In a retrospective analysis of consecutive patients with persistent AF, a decrease in the DF of AF by 11% in response to APVI and ablation of CFAEs was associated with a probability of maintaining sinus rhythm that was similar to that when RFA terminates AF.

Suboptimal cardiovascular risk factor identification and management in patients with rheumatoid arthritis: a cohort analysis

IntroductionAccelerated cardiovascular (CV) disease significantly contributes to increased mortality in rheumatoid arthritis (RA) patients, with a risk comparable to the one observed in patients with type 2 diabetes mellitus (DM). Part of this enhanced risk in RA is attributed to traditional cardiovascular risk factors (CRFs). The aims of this study were to determine how often traditional CRFs are identified and managed by (a) rheumatologists, compared with primary care physicians (PCPs) in RA patients; and (b) PCPs among patients with RA, DM, and the general population (GP).MethodsA retrospective cohort study compared age/gender/ethnicity-matched patients from three groups: RA, DM, and GP (without RA or DM); n = 251 patients per group. Electronic patient records were reviewed during a continuous 12-month period between June 2007 and April 2011 to assess whether CRFs were identified and managed.ResultsIn RA patients, PCPs managed obesity, BP, and lipids significantly more often than did rheumatologists. PCPs managed obesity, BP, and lipids significantly more often in diabetic patients than in the other two groups, and more often in the GP than in RA patients. In patients with elevated BMI, PCPs managed weight in 68% of the DM group, 46% of the GP, and 31% of the RA group (P < 0.0001 for all groups; P = 0.006 between RA and GP groups).ConclusionsRheumatologists identify and manage CRFs less frequently than PCPs. PCPs manage CRFs less frequently in RA patients, compared to the GP and DM. Given the increased CV risk associated with RA, physicians need to more aggressively manage CRFs in these patients.

Anticoagulant therapy and risk of cerebrovascular events after catheter ablation of atrial fibrillation in the elderly.

Stroke and Atrial Fibrillation Ablation. Introduction: Factors associated with cerebrovascular events (CVEs) after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF) have not been well defined in elderly patients (≥65 years). The purpose of this study was to determine the prevalence and predictors of CVEs after RFA in patients with AF ≥65 years old, in comparison to patients <65 years, and with or without AF.

Frequency and spectrum of errors in final radiology reports generated with automatic speech recognition technology.

PURPOSE Automatic speech recognition technology has a high frequency of transcription errors, necessitating careful proofreading and report editing. The purpose of this study was to determine the frequency and spectrum of significant dictation errors in finalized radiology reports generated with speech recognition technology. METHODS All 265 radiology reports that were reviewed in preparation for 12 consecutive weekly multidisciplinary thoracic oncology group conferences were examined for significant dictation errors; reports were compared with the corresponding imaging studies. In addition, departmental radiologists were surveyed regarding their estimates of overall and individual report error rates. RESULTS Two hundred six of 265 (78%) reports contained no significant errors, and 59 (22%) contained errors. Report error rates by individual radiologists ranged from 0% to 100%. There were no significant differences in error rates between native and nonnative English speakers (P > .8) or between reports dictated by faculty members alone and those dictated by trainees and signed by faculty members (P > .3). The most frequent types of errors were wrong-word substitution, nonsense phrases, and missing words. Fifty-five of 88 radiologists (63%) believed that overall error rates did not exceed 10%, and 67 of 88 radiologists (76%) believed that their own individual error rates did not exceed 10%. CONCLUSIONS More than 20% of our reports contained potentially confusing errors, and most radiologists believed that report error rates were much lower than they actually were. Knowledge of the frequency and spectrum of errors should raise awareness of this issue and facilitate methods for report improvement.

Interleukin 17 as a novel predictor of vascular function in rheumatoid arthritis

Background Rheumatoid arthritis (RA) is associated with enhanced cardiovascular (CV) risk and subclinical vascular disease. The proinflammatory milieu has been linked to premature atherosclerosis and endothelial dysfunction in RA. While interleukin 17 (IL-17) is considered pathogenic in RA, its role in determining vascular dysfunction in this disease has not been systematically assessed. Objectives To analyse candidate variables that might determine endothelial function in various vascular territories in a cohort of patients with RA receiving treatment with biological agents, with minimal traditional CV risk factors and low disease activity score. Methods Patients with RA (n=50) receiving stable treatment with biological agents underwent measurement of conduit artery endothelial function by brachial artery flow-mediated dilatation; arterial compliance by pulse wave velocity (PWV) assessment; and endothelium-dependent microvascular testing with Endo-Pat2000 device to assess the reactive hyperaemia index (RHI). IL-17 was quantified by ELISA and disease activity was assessed by 28-joint count Disease Activity Score. Results IL-17 was the main determinant of lower RHI in univariate and multivariate analysis. Traditional and non-traditional CV risk variables determined PWV, with a signifi cant positive association with IL-17 in univariate and multivariate analysis. In contrast, conduit endothelial function was mainly determined by rheumatoid factor titres in univariate and multivariate analysis. Anti-cyclic citrullinated peptide titres, specific disease-modifying antirheumatic drugs or biological agents and disease activity did not determine vascular function. Conclusion In patients with RA treated with biological agents, IL-17 is a main predictor of microvascular function and arterial compliance. This study suggests that IL-17 may play a significant role in development of endothelial dysfunction and cardiovascular disease in RA.

Cross-Sectional Examination Interpretation Discrepancies Between On-Call Diagnostic Radiology Residents and Subspecialty Faculty Radiologists: Analysis by Imaging Modality and Subspecialty

PURPOSE The aim of this study was to identify the rate of discrepancies between radiology residents and faculty radiologists at an academic hospital and to determine the distribution across subspecialties and modalities, specifically CT, MR, and ultrasound. METHODS Consecutive CT, MR, and ultrasound preliminary interpretations rendered by on-call second-year through fourth-year radiology residents for 9 months on emergency department patients, inpatients, and urgent outpatients formed the study population. All preliminary interpretations were graded using a modified RADPEER(®) system (scores 0 and 1 = concordance; score 2 = minor, clinically insignificant discordance; scores 3 and 4 = clinically significant discordance) by the subspecialty faculty members who rendered the final interpretation. RESULTS There were 158 clinically significant discrepancies out of 21,482 preliminary interpretations, for a discrepancy rate of 0.7%. There was no statistically significant difference in rates across subspecialties or between adult and pediatric examinations (cardiothoracic, 1%; abdominal, 0.7%; neuroradiology, 0.6%; musculoskeletal, 0.7%; pediatrics, 0.8%). MR and CT interpretations had significantly higher rates than ultrasound (MR, 1.4%; CT, 0.9%; ultrasound, 0.2%; P < .001). Within neuroradiology, there was a significantly higher rate for MR than CT (1.5% vs 0.6%, P < .01), and within abdominal radiology, there was a significantly higher rate for CT than ultrasound (1.1% vs 0.2%, P < .01). CONCLUSIONS Discrepancy rates in this study were less than or comparable with those reported previously and within or lower than rates for practicing radiologists. Discrepancy rates varied among subspecialties and modalities, suggesting the use of a RADPEER system with attention to modality and subspecialty as a methodology for identifying areas for targeted resident education.

Ulcerlike Projections Developing in Noncommunicating Aortic Dissections: CT Findings and Natural History

OBJECTIVE Aortic ulcerlike projections are focal, contrast-filled outpouchings projecting from the aortic lumen. Our aim was to document the CT findings and natural history of ulcerlike projections developing in patients with preexisting noncommunicating aortic dissection, including intramural hematoma or false lumen thrombosis. MATERIALS AND METHODS By searching the radiology information system, we found 38 ulcerlike projections arising in an underlying noncommunicating aortic dissection that were identified at CT in 24 patients. Clinical factors were determined from patient records. CT scans were reviewed to determine aortic pathology type and appearance time of ulcerlike projections and to measure the diameters of the aorta and ulcerlike projections for comparison over time. Complications were defined as an increase of at least 20% in the diameters of the ulcerlike projections or aorta, the need for surgical repair, or both. Comparisons of ulcerlike projections with and without complications were performed using various statistical tests. RESULTS The underlying aortic disease of the 38 ulcerlike projections was intramural hematoma in 26, false lumen thrombosis in nine, and unknown in three. The mean time of ulcerlike projection appearance was 2.4 months (SD, 1.8) for intramural hematoma and 19.3 months (SD, 18.1) for false lumen thrombosis. Nine of the 28 ulcerlike projections with follow-up scans showed stability, size decrease, or resolution; 10 increased in size; and nine were incorporated into an expanded aortic lumen. Four of 36 ulcerlike projections with imaging or clinical follow-up (or both) required surgical repair. The only clinical or imaging feature significantly associated with the development of complications was false lumen thrombosis (p = 0.04). CONCLUSION Ulcerlike projections forming in noncommunicating dissections may enlarge over time, although they rarely require surgical repair. Given the potential for critical complications, these lesions should be followed with serial CT scans.

Determining the preferred modality for real-time biofeedback during balance training

Vestibular rehabilitation therapy has been shown to improve balance and gait stability in individuals with vestibular deficits. However, patient compliance with prescribed home exercise programs is variable. Real-time feedback of exercise performance can potentially improve exercise execution, exercise motivation, and rehabilitation outcomes. The goal of this study is to directly compare the effects of visual and vibrotactile feedback on postural performance to inform the selection of a feedback modality for inclusion in a home-based balance rehabilitation device. Eight subjects (46.6±10.6years) with peripheral vestibular deficits and eight age-matched control subjects (45.3±11.1years) participated in the study. Subjects performed eyes-open tandem Romberg stance trials with (vibrotactile, discrete visual, continuous visual, and multimodal) and without (baseline) feedback. Main outcome measures included medial-lateral (M/L) and anterior-posterior mean and standard deviation of body tilt, percent time spent within a no-feedback zone, and mean score on a comparative ranking survey. Both groups improved performance for each feedback modality compared to baseline, with no significant differences in performance observed among vibrotactile, discrete visual, or multimodal feedback for either group. Subjects with vestibular deficits performed best with continuous visual feedback and ranked it highest. Although the control subjects performed best with continuous visual feedback in terms of mean M/L tilt, they ranked it lowest. Despite the observed improvements, continuous visual feedback involves tracking a moving target, which was noted to induce dizziness in some subjects with vestibular deficits and cannot be used during exercises in which head position is actively changed or during eyes-closed conditions.