An odd case of hypertension.
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Biomedical subjects
Publications and source records attributed to John E Aruny.
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Vascular access dysfunction is a major source of morbidity for end-stage renal disease patients on hemodialysis. The arteriovenous graft is a common access type for many of these patients. Frequent stenosis formation and thrombosis complicate this form of access. Patients may have a rapidly forming and recurrent venous stenosis at the graft-vein anastomosis that has been seen in both animal models and end-stage renal disease patients to be the result of neointimal hyperplasia. This venous lesion is particularly resistant and sometimes intractable to conventional angioplasty. As a result, new therapies have been developed to reduce the formation and/or recurrence of neointimal hyperplasia. These include special cutting balloons, drug-eluting stents, and endovascular brachytherapy. The authors present the cases of 5 patients with rapidly recurrent venous lesions at the graft-vein anastomosis that derived benefit from angioplasty with the cryoballoon. The time to stenosis or thrombosis in the arteriovenous grafts was increased from a mean of 3 weeks to more than 16 weeks with this technology. Cryotherapy with the cryoballoon (cryoplasty) may represent a useful therapy for patients with intractable stenoses at or near the venous anastomosis of arteriovenous grafts.
BACKGROUND/AIMS: Vascular access thrombosis is one of the most morbid problems encountered by hemodialysis patients. Surveillance protocols utilizing venous pressure (Vp) and vascular access blood flow (VABF) measurements have been employed to preserve vascular access. We undertook a study to evaluate combined dynamic Vp and VABF measurements in the identification of vascular access impairment. We also assessed the effect of preventive repair on thrombosis rates in impaired vascular accesses identified by surveillance. METHODS: Eighty-six chronic hemodialysis patients with a functioning vascular access were enrolled into the surveillance protocol. All vascular accesses with greater than 50% of monthly Vp readings >120 mm Hg or VABF <500 ml/min in arteriovenous fistulas (AVFs) and VABF <650 ml/min in arteriovenous grafts (AVGs), or a decrease in VABF >25% compared to the highest previously measured value, were considered positive. Stenosis >50% on fistulography or a thrombotic event were defined as a 'vascular access impairment episode' while a stenosis <50% or the absence of a thrombotic event was defined as 'no vascular access impairment episode'. Thrombosis rates and intervention rates were calculated per access year at risk. RESULTS: The sensitivity and specificity of the combined surveillance protocol for AVFs were 73.3 and 91%, respectively. In AVGs, they were 68.8 and 87.5%, respectively. The rate of thrombotic events was lower in patients who underwent early repair. The addition of dynamic Vp did not reduce the thrombosis rate any further than surveillance based on VABF alone. CONCLUSION: Combined monitoring for surveillance of AVFs improved sensitivity but had little benefit in AVGs over VABF monitoring alone. Raising VABF cutoff levels might increase and improve identification of vascular access risk for thrombosis, but at the expense of lower specificity.
This report describes a 67-year-old trauma victim in whom a retrievable Günther Tulip (Cook, Bloomington, IN) inferior vena cava filter was placed. The filter migrated to the right atrium immediately after placement. Initial attempts to retrieve the filter with Amplatz Goose Neck snares (Microvena, White Bear Lake, MN) were unsuccessful. A second attempt performed a week later with the addition of the new EnSnare (MDTech, Gainesville, FL) was successful. Possible causes of the migration are discussed and the difficulties encountered while removing this retrievable filter are described.
OBJECTIVE: To determine the usefulness of the rapid parathyroid hormone (PTH) assay during venous localization for primary hyperparathyroidism (1 degrees HPTH). SUMMARY BACKGROUND DATA: Remedial exploration for persistent 1 degrees HPTH poses a significant challenge when noninvasive preoperative localization studies are negative. Based on experience with the intraoperative rapid PTH assay, this technique was extrapolated to the interventional radiology suite and generated near real-time data for the interventional radiologist employing on-site hormone analysis, with a 12-minute turnaround time from blood sampling to assay result. METHODS: Between November 1997 and July 2002, 446 patients with 1 degrees HPTH were referred for treatment. Of these, 56 (12.5%) represented remedial patients who had each undergone one or more previous cervical explorations. Noninvasive imaging studies were positive for or suggestive of localized disease in 49/56 (87.5%) of these patients, who therefore proceeded directly to surgical exploration. Seven patients with persistent 1 degrees HPTH and negative noninvasive studies underwent selective venous sampling employing a rapid PTH assay in the interventional suite. RESULTS: Venous localization demonstrated an apparent PTH gradient in six of the seven patients. In three, a subtle gradient demonstrated in near real-time prompted additional sampling, which confirmed an unequivocal hormone gradient. In an additional case, the absence of a gradient on initial sampling prompted further sampling, which was positive. All of the patients were explored, and in five of the six patients with a positive PTH gradient, a parathyroid adenoma (mean weight 636 +/- 196 mg) was resected from a location predicted by venous localization. In the sixth patient with a positive gradient, parathyroid tissue was not identified; however, there was a significant fall in the intraoperative PTH values, and immediate postoperative and follow-up laboratory data at 1 month are indicative of a cure. In the one patient with negative localization, abnormal parathyroid tissue could not be located during surgical exploration. CONCLUSIONS: The rapid PTH assay is a major adjunct for obtaining informative venous localization in patients with persistent 1 degrees HPTH. This information is extremely helpful to the surgeon in this challenging group of patients and resulted in a 100% cure rate when a venous gradient was demonstrated. The authors now employ this technique routinely in remedial patients with negative noninvasive imaging studies.
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