Raja S. Ramaswamy

Alterations in 3-Hydroxyisobutyrate and FGF21 Metabolism Are Associated With Protein Ingestion–Induced Insulin Resistance

Systemic hyperaminoacidemia, induced by either intravenous amino acid infusion or protein ingestion, reduces insulin-stimulated glucose disposal. Studies of mice suggest that the valine metabolite 3-hydroxyisobutyrate (3-HIB), fibroblast growth factor 21 (FGF21), adiponectin, and nonesterified fatty acids (NEFAs) may be involved in amino acid–mediated insulin resistance. We therefore measured in 30 women the rate of glucose disposal, and plasma 3-HIB, FGF21, adiponectin, and NEFA concentrations, under basal conditions and during a hyperinsulinemic-euglycemic clamp procedure (HECP), with and without concomitant ingestion of protein (n = 15) or an amount of leucine that matched the amount of protein (n = 15). We found that during the HECP without protein or leucine ingestion, the grand mean ± SEM plasma 3-HIB concentration decreased (from 35 ± 2 to 14 ± 1 µmol/L) and the grand median [quartiles] FGF21 concentration increased (from 178 [116, 217] to 509 [340, 648] pg/mL). Ingestion of protein, but not leucine, decreased insulin-stimulated glucose disposal (P < 0.05) and prevented both the HECP-mediated decrease in 3-HIB and increase in FGF21 concentration in plasma. Neither protein nor leucine ingestion altered plasma adiponectin or NEFA concentrations. These findings suggest that 3-HIB and FGF21 might be involved in protein-mediated insulin resistance in humans.

US-Guided, Direct Puncture Retrograde Thoracic Duct Access, Lymphangiography, and Embolization: Feasibility and Efficacy.

PURPOSE To describe technical details, success rate, and advantages of direct puncture of the thoracic duct (TD) under direct ultrasound (US) guidance at venous insertion in the left neck. MATERIALS AND METHODS All patients who underwent attempted thoracic duct embolization (TDE) via US-guided retrograde TD access in the left neck were retrospectively reviewed. Indications for lymphangiography were iatrogenic chyle leak, pulmonary lymphangiectasia, and plastic bronchitis. Ten patients with mean age 41.4 years (range, 21 d to 72 y) underwent US-guided TD access via the left neck. Technical details, procedural times, and clinical outcomes were evaluated. TD access time was defined as time from start of procedure to successful access of TD, and total procedural time was defined from start of procedure until TDE. RESULTS All attempts at TD access via the neck were successful. Technical and clinical success of TDE was 60%. There were no complications. Mean TD access time was 17 minutes (range, 2-47 min), and mean total procedure time was 49 minutes (range, 25-69 min). Mean follow-up time was 5.4 months (range, 3-10 months). CONCLUSIONS TDE via US-guided access in the left neck is technically feasible and safe with a potential decrease in procedure time and elimination of oil-based contrast material.

Modified Balloon-Occluded Retrograde Transvenous Obliteration (BRTO) Techniques for the Treatment of Gastric Varices: Vascular Plug-Assisted Retrograde Transvenous Obliteration (PARTO)/Coil-Assisted Retrograde Transvenous Obliteration (CARTO)/Balloon-Occluded Antegrade Transvenous Obliteration (BATO)

Gastric varices in the setting of portal hypertension occur less frequently than esophageal varices but occur at lower portal pressures and are associated with more massive bleeding events and higher mortality rate. Balloon-occluded retrograde transvenous obliteration (BRTO) of gastric varices has been well documented as an effective therapy for portal hypertensive gastric varices. However, BRTO requires lengthy, higher-level post-procedural monitoring and can have complications related to balloon rupture and adverse effects of sclerosing agents. Several modified BRTO techniques have been developed including vascular plug-assisted retrograde transvenous obliteration, coil-assisted retrograde transvenous obliteration, and balloon-occluded antegrade transvenous obliteration. This article provides an overview of various modified BRTO techniques.

Arterial Embolization for the Treatment of Renal Masses and Traumatic Renal Injuries

Renal artery embolization (RAE) for a variety of indications has been performed for several decades. RAE techniques have been refined over time for clinical efficacy and a more favorable safety profile. Owing to improved catheters, embolic agents for precise delivery, and clinical experience, RAE is increasingly used as an adjunct to, or as the preferred alternative to surgical interventions. The indications for RAE are expanding for many urologic and medical conditions. In this article, we focus on the role and technical aspects of RAE in the treatment of renal masses and traumatic renal injuries.

Endovascular Management of SVC Syndrome due to Fibrosing Mediastinitis—A Feasibility and Safety Analysis

Purpose: To assess the outcomes of endovascular management for superior vena cava (SVC) syndrome secondary to fibrosing mediastinitis (FM). Methods: Between January 2004 and December 2016, 10 consecutive patients with endovascularly managed SVC syndrome secondary to FM were identified in an institutional database. Venograms were performed to assess the severity and location of the lesion and allow measurement for stent selection. Standard stenting and angioplasty techniques were utilized to establish luminal patency. The safety, feasibility, clinical success, and the primary and secondary patency were evaluated. Kaplan-Meier survival analysis was used to determine median duration of stent patency. A log-rank test was used to test differences in prior stent use. Results: Our cohort was predominantly female (7/10) with an average age of 42.2 years. Of the 10 patients, 3 had undergone endovascular stenting at an outside institution prior to referral to our institution due to new, recurrent, or worsening symptoms. All patients underwent venography demonstrating stenosis (8/10) or occlusion (2/10) at initial presentation. Stenting or angioplasty was technically successful in 9 (90.0%) patients. Eight of 10 patients had primary stenting, while 1 achieved vascular patency and symptom resolution with angioplasty alone. Median duration of primary patency was 31.3 months (95% confidence interval: 5.9-103). Six (54.5%) patients required secondary revision procedures. Median duration of secondary patency was 6.1 months, with 25% of revisions occurring by 4 months and 75% occurring by 20.9 months. All treated patients (9/9) reported symptomatic relief at 1-month follow-up, establishing a clinical success rate of 100%. There were no 30-day adverse effects related to the procedure. Conclusion: This study demonstrates that endovascular therapy is a safe and feasible approach for managing FM-related SVC syndrome.

Intravascular access devices from an interventional radiology perspective: indications, implantation techniques, and optimizing patency: IR Perspective On Access Devices

Central venous access has become invaluable in the treatment of patients with a wide array of acute and chronic disease entities. Central venous catheters provide durable, short‐term and long‐term access solutions while saving the patient from repeated peripheral needle sticks. Central venous catheters include: non‐tunneled central venous catheters, tunneled central venous catheters, and port catheters. Typically, the placement of a central venous catheter is performed by Vascular and Interventional Radiologists. The purpose of this article is to familiarize the reader with the role of Interventional Radiology in the placement and management of intravascular or implantable access devices, with a focus on discussing indications for central venous catheter placement, implantation techniques, potential complications, and management of catheter dysfunction.

The muscle anabolic effect of protein ingestion during a hyperinsulinaemic euglycaemic clamp in middle‐aged women is not caused by leucine alone

It has been suggested that leucine is primarily responsible for the increase in muscle protein synthesis after protein ingestion because leucine uniquely activates the mTOR‐p70S6K signalling cascade. We compared the effects of ingesting protein or an amount of leucine equal to that in the protein during a hyperinsulinaemic‐euglycaemic clamp (to eliminate potential confounding as a result of differences in the insulinogenic effect of protein and leucine ingestion) on muscle anabolic signalling and protein turnover in 28 women. We found that protein, but not leucine, ingestion increased muscle p‐mTORSer2448 and p‐p70S6KThr389, although only protein, and not leucine, ingestion decreased muscle p‐eIF2αSer51 and increased muscle protein synthesis.

Acute Lower Extremity Deep Venous Thrombosis: The Data, Where We Are, and How It Is Done

The incidence of venous thromboembolism, including both deep vein thrombosis and pulmonary embolism, is estimated at 300,000-600,000 per year. Although thrombosis may occur anywhere, it is thrombosis of the deep veins of the lower extremities that is of interest as this is where thrombosis occurs most often within the venous system. This article discusses the evaluation and interventions, including endovascular catheter-direct treatments, for patients with acute deep venous thrombosis.

Endovascular Treatment of Deep Vein Thrombosis

Venous thromboembolic disease (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE), is a major health problem in the United States and worldwide. Lower extremity DVT is a serious medical condition with short- and long-term complications that can result in major disability as a result of pulmonary embolism, postthrombotic syndrome, paradoxical embolization, and/or limb amputation. Although anticoagulation is the mainstay, first-line treatment, the last two decades have seen increased use of catheterbased methods to treat acute deep venous thrombosis. The purpose of this chapter is to highlight the rationale, safety profile, evidence, and clinical outcomes that are achieved utilizing endovascular methods for the treatment of acute DVT.

Thermal ablation versus surgical resection for localized hepatocellular carcinoma: a population study using the SEER database

AIM To compare overall survival (OS) and liver cancer-specific survival (LCSS) in patients with localized hepatocellular carcinoma treated with surgical resection (SR) or thermal ablation (TA) using the Surveillance, Epidemiology and End Results database. MATERIALS & METHODS Kaplan-Meier, competing risk and Cox regression analyses were performed after identifying patients. Propensity score matching was then applied. RESULTS There was significantly better OS in the SR group and significantly lower probability of LCSS in the TA group. After matching, there was significantly longer OS in the SR group and a lower probability of LCSS in the TA group. CONCLUSION SR offered a significant survival benefit over TA for localized hepatocellular carcinoma.