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Background: The segment of the vein mobilized for arterial anastomosis in the creation of an arteriovenous fistula (AVF) is the swing segment. This segment may experience turbulent flow and altered shear mechanical stress that result in stenosis. We sought to determine the frequency of stenotic lesions in the swing segment.Study Design: Case series.Settings& Participants: From January 31, 2003, to June 30, 2005, records of all patients referred to an outpatient hemodialysis vascular access center for AVF dysfunction were reviewed (n = 484). Of these, 278 patients had angiographically documented stenosis (any degree of luminal narrowing) on their first visit.Outcomes& Measurements: Distribution of stenoses in different segments of the AVF. Swing-segment stenoses were classified as proximal (outflow into axillary vein system), distal or juxta-anastomotic (adjacent to the anastomosis), and the cephalic arch.Results: Overall prevalence of angiographically documented swing segment stenosis (proximal, distal or juxta-anastomotic, and cephalic arch) was 45.7% (127 of 278 patients), whereas the remaining stenoses (151 of 278 patients) were distributed among the puncture zone, arterial, arterial anastomosis, and central veins. The most frequent location of the swing-segment stenosis was juxta-anatomosis (63%; 80 of 127 patients), followed by cephalic arch (19%; 24 of 127 patients) and proximal swing segment (18%; 23 of 127 patients). The distribution of swing-segment stenosis (n = 127) was equivalent among the various fistulas (brachial-cephalic, 35.4%; radial-cephalic, 33.9%; and brachial-basilic, 30.7%). Eighty-three percent of swing-segment stenoses were significant (>50% luminal narrowing) and underwent percutaneous transluminal angioplasty, with a 93% success rate.Limitations: Retrospective nature of the study and potential selection bias.Conclusion: In our population, swing-segment stenosis is the most common lesion in dysfunctional AVFs; juxta-anastomotic stenosis is the predominant lesion independent of fistula type. Whether the occurrence of swing-segment stenosis is caused by mobilization of the vein during surgery is not clear. [ABSTRACT FROM AUTHOR]

Objectives: Controversy exists regarding utility of cardiac troponin I (cTnI) in predicting significant coronary artery disease (CAD) in hemodialysis (HD) patients with chest pain and no acute ischemia on electrocardiogram (non-ST segment elevation myocardial infarction, non-STEMI). We sought to determine if cTnI elevation predicts significant CAD (>70% stenosis) in these patients., Methods: Ninety patients with non-STEMI referred for cardiac catheterization were included, divided equally into HD and non-HD groups., Results: Mean age and baseline characteristics were not significantly different between groups, except for left ventricular hypertrophy which was higher in HD patients (56 vs. 27%, p = 0.012). Initial cTnI correlated with obstructive CAD and was stratified into <0.3 and >0.3 ng/ml. By logistic regression, cTnI >0.3 ng/ml was not predictive of CAD in HD patients [odds ratio = 0.87 (95% CI 0.19-4.0), p = 0.8], while non-HD patients had an increased risk of CAD if first cTnI was >0.3 ng/ml [odds ratio = 1.461 (95% CI 1.01-2.11), p = 0.04] as expected. Sensitivity, specificity, negative and positive predictive values of cTnI in predicting obstructive CAD were better in non-HD patients., Conclusion: cTnI in these patients had no predictive value for obstructive CAD. This contrasts with the general population, suggesting a higher index of suspicion for high-grade CAD irrespective of cTnI levels in HD patients.

Radiocontrast exposure has now become an important cause of iatrogenic acute kidney injury (AKI) in hospitalized patients due to an increase in the number of diagnostic and interventional procedures done. Gadolinium, a well-known paramagnetic contrast agent used primarily for magnetic resonance imaging (MRI), has attracted a lot of attention for its safety in patients at risk for AKI, namely those with chronic kidney disease (CKD) and diabetes. Since its widespread use, a few cases of gadolinium nephrotoxicity have been reported in the literature. However, this remains a largely unrecognized complication in the field of nephrology. Here we describe such a case of AKI due to gadolinium toxicity in a 65-year-old African-American man with a history of hypertension, diabetes and chronic kidney disease, who was admitted for a toe infection and consequently developed AKI from multiple imaging studies involving the use of gadolinium.