Peak systolic velocity and color aliasing are important in the development of duplex ultrasound criteria for external carotid artery stenosis.

OBJECTIVE: The external carotid artery (ECA) serves as a major collateral pathway for ophthalmic and cerebral artery blood supply. It is routinely examined as part of carotid duplex ultrasound, but criteria for determining ECA stenosis are poorly characterized and typically extrapolated from internal carotid artery data. This is despite the fact that the ECA is smaller in diameter, with a higher resistance and lower volume flow pattern. We hypothesized that using the cutoff of a peak systolic velocity (PSV) ≥125 cm/s, extrapolated from internal carotid artery data, will overestimate the prevalence of ≥50% ECA stenosis and aimed to determine a more appropriate criterion. METHODS: From December 2016 to July 2017, consecutive carotid duplex ultrasound studies performed in our university hospital Intersocietal Accreditation Commission-accredited vascular laboratory were prospectively identified and categorized with respect to prevalence and distribution of ECA PSVs and color aliasing, an indication of turbulent flow or flow acceleration. Presence of color aliasing was determined by two individual reviewers and agreement assessed by Cohen κ coefficient. ECA stenosis was calculated by the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method in patients with computed tomography angiography (CTA) performed within 3 months of carotid duplex ultrasound without an intervening intervention. Receiver operating characteristic analysis was performed to identify best criteria for determining ≥50% ECA stenosis. RESULTS: There were 1324 ECAs from 662 patients analyzed; 174 patients had a total of 252 ECAs with PSV ≥125 cm/s (19% of the total sample). Of those ECAs with PSVs ≥125 cm/s, 30.5% were between 125 and 149 cm/s, 22.2% were between 150 and 174 cm/s, 13.1% were between 175 and 199 cm/s, and 34.1% were ≥200 cm/s. There were 341 ECAs that were analyzed for the presence of color aliasing. In 86 ECAs with PSV ≥200 cm/s, 58.1% had color aliasing, whereas in 255 ECAs with PSV <200 cm/s, only 19.2% had color aliasing (P = .0001). There were 325 CTA studies reviewed and assessed for the presence of a ≥50% ECA stenosis as determined by CTA. Overall, the combination of an ECA PSV ≥200 cm/s with the presence of color aliasing provided the highest combination of sensitivity (90%), specificity (96%), positive predictive value (83%), and negative predictive value (98%) and the greatest area under the curve of 0.971 for determining the presence of a ≥50% ECA stenosis based on CTA. CONCLUSIONS: A PSV ≥125 cm/s alone probably overestimates the prevalence of ≥50% ECA stenosis. A PSV ≥200 cm/s combined with color aliasing is highly predictive of >50% ECA stenosis based on correlation with CTA.

Ambulation and functional outcome after major lower extremity amputation.

OBJECTIVE: Major lower extremity amputations (MLEAs) remain a significant source of disability. It is unknown whether postamputation functional outcomes and outcome predictability have changed with a population of increasingly aging and obese patients. Accordingly, we sought to evaluate contemporary trends. METHODS: A retrospective chart review was performed to identify patients undergoing MLEA using Current Procedural Terminology codes in a university hospital. Demographics, comorbidities, perioperative variables, and outcomes were obtained. Descriptive statistics, t-tests, and χ2 and multivariate logistic regression modeling were used where appropriate. Survival analyses were performed with the Kaplan-Meier method. RESULTS: From October 2005 to November 2016, 206 patients (147 male; mean age, 63 ± 13.5 years) underwent 256 MLEAs (90.9% below-knee amputations, 1.3% through-knee amputations, and 7.8% above-knee amputations [AKAs]) related to acute and critical limb ischemia, infection, or other causes. Mean follow-up was 178.7 ± 266.9 days. Conversion from below-knee amputation to AKA was 3.5%. Estimated 1-year survival was 83%, and it was 15% lower in nonambulatory patients (75% vs 90%; P = .04). Overall 1-year postamputation ambulatory rate was 46.1%. Nonambulatory patients had a higher body mass index (30.9 ± 8.0 vs 25.6 ± 5.4; P < .001), lower preoperative hematocrit (31.0% ± 7.4% vs 33.3% ± 8.1%; P < .05), higher modified frailty index (mFI; 8.4 ± 1.0 vs 5.4 ± 1.2; P < .0001), higher chronic alcohol use (9% vs 1%; P = .01), dependent preoperative functional status (29% vs 2.1%; P < .01), and lack of family support (66.3% vs 17.9%; P < .01); they were less likely to be married (83.2% vs 35.8%; P < .01) and more likely to have an AKA (20% vs 52.6%; P = .004). There were no patients with dementia, on dialysis, or with bilateral MLEAs who were ambulatory after amputation. Factors predictive of nonambulatory status after MLEA with multivariate logistic regression analysis included increased body mass index (odds ratio [OR], 0.88; 95% confidence interval [CI], 0.81-0.98; P = .017) and an increased mFI (OR, 0.23; 95% CI, 0.16-0.34; P < .0001); a higher hemoglobin level was protective (OR, 1.3; 95% CI, 1.03-1.62; P = .019). CONCLUSIONS: Patients should be counseled that <50% of patients receiving MLEAs are ambulatory after amputation. Educating patients about the deleterious effects of obesity on ambulatory status after MLEA may motivate patients to improve their level of fitness to achieve successful ambulation. Patients with an elevated mFI, patients with dementia, and those on dialysis should be considered for AKAs.

Twenty-Year Experience with Aorto-Enteric Fistula Repair: Gastrointestinal Complications Predict Mortality.

BACKGROUND: Aorto-enteric fistulas (AEF) represent a lethal subset of aortic graft infections. The optimal management of AEF remains unclear. We aimed to identify predictors of morbidity and mortality. STUDY DESIGN: We performed a single-center retrospective review of consecutive AEF repairs. Demographics, comorbidities, and perioperative variables were obtained. Descriptive statistics, chi-square, Kruskall-Wallis, and Cox proportional-hazards modeling were used where appropriate. RESULTS: Between June 1995 and October 2014, 50 patients (30 male; 60%) presented with AEF, with a median age of 70 years (interquartile range [IQR] 61 to 75 years). Median follow-up for the entire cohort was 14 months (IQR 5 to 27 months). Thirty-four (68%) subjects underwent aortic reconstruction with femoral vein; 12 (24%) with extra-anatomic bypass and aortic ligation; 3 (6%) with rifampin-soaked Dacron graft; and 1 (2%) with cryopreserved aortic allograft. The duodenum was the most common location of the enteric defect (n = 40, 80%). Duodenal leak complicated 6 (12%) of the primary enteric repairs, but none of the complex enteric repairs performed with resection and/or bypass. Twenty-three patients (46%) died by 60 days. Advanced age, chronic renal insufficiency, any complications, and gastrointestinal (GI) complications (n = 13, 26%) were all associated with an increase in overall mortality on univariate analysis (p < 0.05). Gastrointestinal complications (hazard ratio [HR] 3.23; 95% CI 1.27 to 8.25; p = 0.015) and advanced age (HR 1.07; 95% CI 1.01 to 1.13; p = 0.01) were the only independent predictors of mortality on multivariable regression models. CONCLUSIONS: Over 20 years, approximately 50% of patients with AEF repairs died within 60 days. Gastrointestinal complications increase the risk of mortality more than 3-fold, representing an attractive surgically modifiable risk factor. Future multicenter studies are required to clarify optimal methods of arterial and GI reconstruction in AEF.

Uncertain Patency of Covered Stents Placed for Traumatic Axillosubclavian Artery Injury.

BACKGROUND: Traumatic axillosubclavian artery injuries (ASAIs) are uncommon but devastating. There is increasing acceptance of covered stent use for ASAIs. However, epidemiologic and long-term outcomes data are limited. We investigated national trends in ASAI management and our institutional outcomes after emergent covered stent placement and open surgical repairs for ASAIs. STUDY DESIGN: A review of the National Trauma Data Bank from 2010 to 2012 was performed for epidemiologic data. International Classification of Diseases and procedure codes were used to identify ASAIs and therapy type. A single-center, retrospective review of consecutive patients with ASAIs between January 2010 and August 2014 was also performed. RESULTS: National Trauma Data Bank review included 511,286 patients with 520 ASAIs, yielding an incidence of 0.1%. Endovascular therapy was used in 76 patients (14.7%) vs open repair in 280 patients (53.8%). Nonoperative or unknown treatment was used in 164 (31.5%). From 2010 to 2012, endovascular interventions increased from 11.3% to 17.2% (p < 0.05). Endovascular therapy was used more frequently in blunt compared with penetrating trauma (59.2% vs 40.8%; p < 0.005). Our institutional review identified 10 ASAIs treated with covered stents with a median follow-up of 117 days (interquartile range 13 to 447 days) and 70% lost to follow-up. No treatment-related mortality or amputation occurred. Stent occlusion occurred in 30% at a median of 132 days (interquartile range 30 to 223 days). Three patients with ASAIs were initially treated with open surgery, 2 died and the third required ligation. CONCLUSIONS: Covered stents are being used increasingly for ASAIs nationwide, despite variable reports of durability. Follow-up is poor in urban trauma centers and might be responsible for the variable patency. Population-based efforts to improve compliance among trauma patients can help improve covered stent patency in ASAI.

Endothelial cells are susceptible to rapid siRNA transfection and gene silencing ex vivo.

BACKGROUND: Endothelial gene silencing via small interfering RNA (siRNA) transfection represents a promising strategy for the control of vascular disease. Here, we demonstrate endothelial gene silencing in human saphenous vein using three rapid siRNA transfection techniques amenable for use in the operating room. METHODS: Control siRNA, Cy5 siRNA, or siRNA targeting glyceraldehyde-3-phosphate dehydrogenase (GAPDH) or endothelial specific nitric oxide synthase (eNOS) were applied to surplus human saphenous vein for 10 minutes by (i) soaking, (ii) applying 300 mm Hg hyperbaric pressure, or (iii) 120 mm Hg luminal distending pressure. Transfected vein segments were maintained in organ culture. siRNA delivery and gene silencing were assessed by tissue layer using confocal microscopy and immunohistochemistry. RESULTS: Distending pressure transfection yielded the highest levels of endothelial siRNA delivery (22% pixels fluorescing) and gene silencing (60% GAPDH knockdown, 55% eNOS knockdown) as compared with hyperbaric (12% pixels fluorescing, 36% GAPDH knockdown, 30% eNOS knockdown) or non-pressurized transfections (10% pixels fluorescing, 30% GAPDH knockdown, 25% eNOS knockdown). Cumulative endothelial siRNA delivery (16% pixels fluorescing) and gene silencing (46% GAPDH knockdown) exceeded levels achieved in the media/adventitia (8% pixels fluorescing, 24% GAPDH knockdown) across all transfection methods. CONCLUSION: Endothelial gene silencing is possible within the time frame and conditions of surgical application without the use of transfection reagents. The high sensitivity of endothelial cells to siRNA transfection marks the endothelium as a promising target of gene therapy in vascular disease.

Infectious mononucleosis with secondary cold agglutinin disease causing autoimmune haemolytic anaemia.

This case report describes a 20-year-old woman whose initial clinical, laboratory, and radiological presentation suggested obstructive jaundice. However, she was subsequently found to be suffering from autoimmune haemolytic anaemia resulting from an Epstein-Barr virus infection complicated by cold agglutinin disease. The patient went on to make a complete clinical recovery after discharge.

The reduction of platinum(IV) and palladium(IV) ions by 2,6-pyridinedihydroxamic acid.

Reaction of K(2)[Pt(IV)Cl(6)] and K(2)[Pd(IV)Cl(6)] with 2,6-pyridinedihydroxamic acid (2,6-pyha) and its disodium salt, 2,6-pyhaNa(2), yielded not the desired Pt(IV) and Pd(IV) 2,6-pyridinedihydroxamato complexes, but rather the Pt(II) and Pd(II) 2,6-pyridinedicarboxylato complexes, trans-[Pt(II)(2,6-pyca(H-1))(2)].2H(2)O and trans-[Pd(II)(2,6-pyca(H-1))(2)].2H(2)O respectively (2,6-pyca = 2,6-pyridinedicarboxylic acid). Thus in the presence of Pt(IV) and Pd(IV), the dihydroxamic acid was adventitiously hydrolysed to the corresponding dicarboxylic acid and Pt(IV) and Pd(IV) reduced to Pt(II) and Pd(II) in situ. The X-ray crystal structures of 2,6-pyha, 2,6-pyhaNa(2).8H(2)O, trans-[Pt(II)(2,6-pyca(H-1))(2)].2H(2)O and trans-[Pd(II)(2,6-pyca(H-1))(2)].2H(2)O are reported, together with a possible mechanism for the metal-assisted hydrolysis of the dihydroxamic acid and reduction of Pt(IV) and Pd(IV) to Pt(II) and Pd(II) respectively.