Charles A. Owens

Islet Transplantation for Brittle Type 1 Diabetes: The UIC Protocol

This prospective phase 1/2 trial investigated the safety and reproducibility of allogeneic islet transplantation (Tx) in type I diabetic (T1DM) patients and tested a strategy to achieve insulin‐independence with lower islet mass. Ten C‐peptide negative T1DM subjects with hypoglycemic unawareness received 1–3 intraportal allogeneic islet Tx and were followed for 15 months. Four subjects (Group 1) received the Edmonton immunosuppression regimen (daclizumab, sirolimus, tacrolimus). Six subjects (Group 2) received the University of Illinois protocol (etanercept, exenatide and the Edmonton regimen). All subjects became insulin‐ independent. Group 1 received a mean total number of islets (EIN) of 1460 080 ± 418 330 in 2 (n = 2) or 3 (n = 2) Tx, whereas Group 2 became insulin‐ independent after 1 Tx (537 495 ± 190 968 EIN, p = 0.028). All Group 1 subjects remained insulin free through the follow‐up. Two Group 2 subjects resumed insulin: one after immunosuppression reduction during an infectious complication, the other with exenatide intolerance. HbA1c reached normal range in both groups (6.5 ± 0.6 at baseline to 5.6 ± 0.5 after 2–3 Tx in Group 1 vs. 7.8 ± 1.1 to 5.8 ± 0.3 after 1 Tx in Group 2). HYPO scores markedly decreased in both groups. Combined treatment of etanercept and exenatide improves islet graft function and facilitates achievement of insulin‐independence with less islets.

Efficacy and Safety of Flow-Directed Pulmonary Artery Catheter Thrombolysis for Treatment of Submassive Pulmonary Embolism

OBJECTIVE The purpose of this study was to assess the efficacy and safety of flow-directed catheter thrombolysis for treatment of submassive pulmonary embolism (PE). MATERIALS AND METHODS In this single-institution retrospective study, 19 patients (nine men and 10 women; mean age [± SD], 54 ± 13 years) with submassive PE underwent catheter-directed thrombolysis between 2009 and 2013. Presenting symptoms included dyspnea in 18 of 19 (95%) cases. Submassive PE was diagnosed by pulmonary CT arteriography and right ventricular strain. PE was bilateral in 17 of 19 (89%) and unilateral in two of 19 (11%) cases. Thrombolysis was performed via a pulmonary artery (PA) catheter infusing 0.5- 1.0 mg alteplase per hour and was continued to complete or near complete clot dissolution with reduction in PA pressure. IV systemic heparin was administered. Measured outcomes included procedural success, PA pressure reduction, clinical success, survival, and adverse events. RESULTS Procedural success, defined as successful PA catheter placement, fibrinolytic agent delivery, PA pressure reduction, and achievement of complete or near complete clot dissolution, was achieved in 18 of 19 (95%) cases. Thrombolysis required 57 ± 31 mg of alteplase administered over 89 ± 32 hours. Initial and final PA pressures were 30 ± 10 mm Hg and 20 ± 8 mm Hg (p < 0.001). All 18 (100%) technically successful cases achieved clinical success because all patients experienced symptomatic improvement. Eighteen of 19 (95%) patients survived to hospital discharge; 18 of 19 (95%) and 15 of 16 (94%) patients had documented 1-month and 3-month survival. One fatal case of intracranial hemorrhage was attributed to supratherapeutic anticoagulation because normal fibrinogen levels did not suggest remote fibrinolysis; procedural success was not achieved in this case because of early thrombolysis termination. No other complications were encountered. CONCLUSION Among a small patient cohort, flow-directed catheter thrombolysis with alteplase effectively dissolved submassive PE and reduced PA pressure. Postprocedure short-term survival was high, and patients undergoing thrombolysis required close observation for bleeding events.

Pulmonary Embolism from Upper Extremity Deep Vein Thrombosis and the Role of Superior Vena Cava Filters: A Review of the Literature

The placement of superior vena cava (SVC) filters to prevent pulmonary emboli (PE) from upper-extremity deep vein thrombosis (UEDVT), although controversial, has been reported. A total of 21 publications were identified that reported 209 SVC filters and documented eight major filter-related complications (3.8%), including four cardiac tamponades, two aortic perforations, and one recurrent pneumothorax. The in-hospital or 1-month mortality rate was 43.1%. Twenty-eight additional publications were identified that reported 3,747 cases of UEDVT. The rates of PE and associated mortality were 5.6% and 0.7%, respectively. Studies imaging both upper and lower extremities found deep vein thrombus 14.7 times more likely to occur in the lower extremities and the rate of PE from a lower-extremity thrombus to be 25.1%. The lack of evidence documenting the risk from UEDVT and the absence of data supporting the safety and efficacy of SVC filters bring their benefit into question.

The inaccuracy of duplex ultrasonography in predicting patency of transjugular intrahepatic portosystemic shunts

BACKGROUND & AIMS A prospective double-blinded study with preset sonographic criteria has not been performed to assess the accuracy of duplex ultrasonography in determining the patency of transjugular intrahepatic portosystemic shunts (TIPS). The purpose of this study was to determine the sensitivity and specificity of duplex ultrasonography in predicting shunt malfunction using accepted preset sonographic criteria. METHODS Sixty ultrasonographic and venographic follow-up comparisons were made on 38 cirrhotic patients who had undergone TIPS placement for variceal bleeding (n = 28) or intractable ascites (n = 10). Ultrasonographic results were analyzed by one of two board-certified ultrasonographers without knowledge of venographic findings. RESULTS Of the 31 occluded (n = 8) and stenotic (n = 23) shunts, ultrasonography accurately predicted a shunt malfunction (occlusion or stenosis) in only 11 studies and incorrectly predicted patency in 20. Compared with venography, ultrasonography had a sensitivity of 35% and a specificity of 83% in predicting TIPS stenosis or occlusion. CONCLUSIONS These results suggest that duplex sonography is not a sensitive test in predicting the presence of a hemodynamically significant stenosis and that shunt status should be assessed by venography and direct portal pressure measurements until a more reliable and proven noninvasive ultrasonographic criterion is devised.

Comprehensive Review of TIPS Technical Complications and How to Avoid Them

OBJECTIVE The goal of this article is to describe potential technical complications related to transjugular intrahepatic portosystemic shunts (TIPS) placement and to discuss strategies to avoid and manage complications if they arise. CONCLUSION TIPS is an established interventional therapy for complications of portal hypertension. Although TIPS remains a relatively safe procedure, direct procedure-related morbidity rates are as high as 20%. The technical complexity of this intervention increases the risk for methodologic mishaps during all phases of TIPS placement, including venous access and imaging, transhepatic needle puncture, shunt insertion, and variceal embolization. Thus, interventional radiologists require a thorough stepwise understanding of TIPS insertion, possible adverse sequela, and technical tips and tricks to maximize the safety of this procedure.

TIPS for Treatment of Variceal Hemorrhage: Clinical Outcomes in 128 Patients at a Single Institution over a 12-Year Period

PURPOSE To assess clinical outcomes of transjugular intrahepatic portosystemic shunt (TIPS) treatment of variceal hemorrhage. MATERIALS AND METHODS A total of 128 patients (82 men and 46 women; mean age, 52 y) with liver cirrhosis and refractory variceal hemorrhage underwent TIPS creation from 1998 to 2010. Mean Child-Pugh and Model for End-stage Liver Disease (MELD) scores were 9 and 18, respectively. From 1998 to 2004, 12-mm Wallstents (n = 58) were used, whereas from 2004 to 2010, 10-mm VIATORR covered stent-grafts (n = 70) were used. Technical success, hemodynamic success, complications, shunt dysfunction, recurrent bleeding, and overall survival were assessed. RESULTS Technical and hemodynamic success rates were 100% and 94%, respectively. Mean portosystemic gradient reduction was 13 mm Hg. Complications at 30 days included encephalopathy (14%), renal failure (5.5%), infection (1.6%), and liver failure (0.8%). Shunt patency rates were 93%, 82%, and 60% at 30 days, 1 year, and 2 years, respectively. Dysfunction, or loss of TIPS primary patency, occurred more with Wallstent versus VIATORR TIPSs (29% vs 11%; P = .009). Recurrent bleeding incidences were 9%, 22%, and 29% at 30 days, 1 year, and 2 years, respectively, and were similar between Wallstent and VIATORR TIPSs (19% vs 19%; P = .924). Variceal embolization significantly reduced recurrent bleeding rates (5% vs 25%; P = .013). Overall survival rates were 80%, 69%, and 65% at 30 days, 1 year, and 2 years, respectively, and were similar between Wallstent and VIATORR TIPSs (35% vs 26% mortality rate; P = .312). Advanced MELD score was associated with increased mortality on multivariate analysis. CONCLUSIONS Wallstent and VIATORR TIPSs effectively treat variceal hemorrhage, particularly when accompanied by variceal embolization. Although TIPS with a VIATORR device showed improved shunt patency, patient survival is similar to that with Wallstent TIPS. These results further validate TIPS creation for refractory variceal bleeding.

Results of endoluminal grafting in an experimental aortic aneurysm model

We studied the impact of an endoluminally placed stented aortic graft on the geometry of a surgically created abdominal aortic dilation (AAD) in nonatherosclerotic mongrel dogs. Patulous iliac vein patch infrarenal aortoplasty produced a fusiform AAD, doubling the aorta diameter. Lumbar and mesenteric aortic tributaries were preserved and no mural thrombus formed. AADs created in 23 dogs were endoluminally excluded through transfemoral placement of a thin-wall Dacron graft 4 +/- 2 months later. Balloon-expandable stents were used to anchor each end of the graft to the aorta. The graft was crimped radially in its body and longitudinally at its ends to provide longitudinal and radial expandability in these respective zones. Serial color duplex, angiography, and direct caliper measurements were made. Before graft placement, a 19% +/- 11% diameter growth was observed. At graft placement, flow arrest immediately occurred in the space between the graft and the AAD intima in all cases. Although microscopic recanalization of the thrombus in this space was seen at sacrifice 6 and 12 months later, no macroscopic duplex flow was imaged. A 10% +/- 11% reduction in AAD diameter was measured at 6 months (p < 0.001), with no further reduction at 12 months. Graft dimensions remained stable. No anastomotic leaks developed. AAD growth stopped during the first year after effective endoluminal exclusion in normotensive dogs despite patent side branches (< 1.5 mm internal diameter) and no mural thrombus at the time of graft placement. Whether microscopic recanalization of the thrombus that forms outside the graft has an impact after 1 year remains to be seen.

Ultrasound-Enhanced Thrombolysis: EKOS EndoWave Infusion Catheter System

The purpose of the EKOS EndoWave Infusion Catheter System is to enhance catheter-directed thrombolysis by accelerating the fibrinolytic process with the application of ultrasound. Improving the efficiency of the thrombolytic process reduces the treatment time and total lytic dose delivered, thereby lowering the overall cost of therapy and the risk of an associated bleeding complication.

Current Tumor Ablation Technologies: Basic Science and Device Review

Image-guided tumor ablation is an increasingly utilized tool to treat focal malignancy. Tumor ablation can be divided into two large categories, thermal and chemical ablation. The authors provide an overview of the current methods used to achieve thermal and chemical ablation of tumors, specifically addressing the basic science behind the ablation methods as well as providing a brief synopsis of the commercial devices currently available for use in the United States.

Pulmonary Artery Pseudoaneurysm After Tube Thoracostomy

Pulmonary artery pseudoaneurysm has been described as a complication of Swan-Ganz catheterization and right heart catheterization. Isolated cases of this condition occurring in blunt and penetrating chest trauma have been reported. In this communication, we describe the case of a patient with intracranial hemorrhage who required positive-pressure ventilation and in whom subsequent pneumothorax developed, necessitating tube thoracostomy. A persistent opacification of the lung field resulted in evaluation with computed chest tomography and color-flow Doppler ultrasonography. A pseudoaneurysm of the lingular segmental artery was identified and successfully obliterated by Gelfoam coil embolization.