Lawrence G. Sahler

Superselective Microcoil Embolization for the Treatment of Lower Gastrointestinal Hemorrhage

PURPOSE To evaluate the safety and effectiveness of superselective microcoil embolization for the treatment of lower gastrointestinal (LGI) hemorrhage. MATERIALS AND METHODS A retrospective review of LGI superselective microcoil embolization data for a 10-year period was performed. During this period, twenty-two patients with evidence on angiography of LGI bleeding underwent superselective microcoil embolization. Hemorrhage was treated in the colon (n = 19) and jejunum (n = 3). Ivalon was used adjunctively in two patients and gelfoam was used as a secondary agent in two additional patients. Postembolization ischemia was evaluated objectively in 14 patients by colonoscopy (n = 10), surgical specimen (n = 3), and barium enema (n = 1). All patients were followed for clinical evidence of bowel ischemia. Four patients died before further follow-up could be performed. Additionally, 122 cases of LGI hemorrhage treated with superselective microcoil embolization were identified in a review of the literature. A meta-analysis was then performed, combining the data in this study and the data from the literature, to estimate the rate of major and minor ischemic complications on a total of 144 superselective microcoil embolizations. RESULTS Immediate hemostasis was achieved in all 22 patients in this study. Complete clinical success was achieved in 86% of patients (19 of 22 patients). Rebleeding occurred in 14% of patients (3 of 22 patients) and each underwent colonoscopic intervention with success. Postembolization objective follow-up was performed in 64% of patients (14 of 22 patients). Ten patients underwent follow-up colonoscopy; one patient received a follow-up barium enema; and three patients underwent subsequent surgery. Colonic resection (one partial and one total) was performed in two patients. The partial colectomy was performed in a patient who had been diagnosed with colonic polyps and dysplasia. The total colectomy was performed on a patient with history of chronic LGI bleeding complicated by long-term anticoagulation therapy and a history of tubular adenoma resection. The third surgical patient (16 months old) underwent a follow-up exploratory laparotomy after embolization of a proximal jejunal branch of the superior mesenteric artery. None of the three patients who underwent surgery were found to have postembolic ischemic changes in the bowel specimen. Four patients in this study died, for reasons unrelated to hemorrhage or embolization, before further follow-up could be performed. The last four patients were followed clinically and experienced no symptoms of intestinal ischemia. A minor ischemic complication was reported in 4.5% of patients (1 of 22 patients), and there were no major ischemic complications (0%) in this series. A review of the data from 122 cases of LGI superselective microcoil embolization in the literature is also presented. Combined with the data in this study, the minor complication rate was 9% (13 of 144 patients), and the major complication rate was 0% (0 of 144 patients). CONCLUSION Superselective microcoil embolization is a safe and effective treatment for LGI hemorrhage.

Transhepatic Dilation of Anastomotic Biliary Strictures in Liver Transplant Recipients with Use of a Combined Cutting and Conventional Balloon Protocol: Technical Safety and Efficacy

PURPOSE To determine the safety and technical efficacy of a transhepatic dilation protocol involving the use of a combined cutting and conventional balloon protocol in the management of anastomotic biliary strictures in adult liver transplant recipients. MATERIALS AND METHODS Retrospective review of adult transplant recipients undergoing transhepatic cutting balloon dilation for anastomotic biliary strictures was performed over a period of 8 months. Cutting balloon dilation was followed by conventional balloon dilation with use of a balloon with a diameter at least as large as that of the initial cutting balloon. Technically successful dilation was defined by improvement of the biliary stricture. A technically successful regimen was defined by a residual stenosis less than 30% after a maximum of three sessions. The technical results were stratified according to lesions treated for the first time and those with restenosis. Comparison among institutions in terms of published methods and technical results were made. RESULTS Twenty-two patients with liver transplants underwent 49 cutting balloon dilation sessions as part of 27 regimens (1.8 sessions per regimen): 12 cases of primary treatment, 10 cases of restenosis, four for intraprocedural failures of conventional balloon dilation, and one for the latter two indications. Technical success rates of regimens for primary stenoses, restenoses, and all cases were 100%, 90%, and 93%, respectively. These results compare favorably with historic intrainstitutional results, which are 89%, 73%, and 85% for primary stenoses, restenoses, and all cases, respectively. In addition, no biliary ruptures or cases of major hemobilia were encountered. Minor hemobilia was encountered in 10% of cases. CONCLUSIONS The use of commercially available cutting balloons augmented subsequently with larger conventional balloons is safe for transhepatic balloon dilation and can increase the technical success rate of percutaneous management of transplant biliary strictures.

Transhepatic balloon dilation of anastomotic biliary strictures in liver transplant recipients : The significance of a patent hepatic artery

PURPOSE To determine the significance of hepatic artery steno-occlusive disease on the patency of anastomotic biliary strictures in liver transplant recipients after transhepatic balloon dilation. MATERIALS AND METHODS A retrospective review of records of all patients undergoing transhepatic balloon dilation for anastomotic biliary strictures after orthotopic liver transplantation was performed over an 8-year period. Patency of the anastomosis was based on subsequent cholangiography. The presence of hepatic artery steno-occlusive disease was determined by Doppler ultrasound and/or angiography. The anastomotic biliary stricture patency rates were calculated by the Kaplan-Meier method. RESULTS Thirty-eight patients who had undergone liver transplants underwent 53 balloon dilations for anastomotic biliary strictures (nine patients for arterial disease, 26 patients had patent arteries and three patients had arteries of indeterminate patency). Eight of the 53 strictures treated (15%) were refractory to balloon dilation: 10.5% of first comers and 27% of restenotic lesions. Two of the 53 strictures treated (4%) had significant complications: hemobilia requiring blood transfusion and ductal rupture. One-year cumulative primary patency rates for anastomotic biliary strictures for patients with arterial disease, patent hepatic arteries, and all-comers were: 0%, 45% (P = .01), and 36%, respectively. One-year cumulative primary patency rates for choledocho-choledocal and choledocho-jejunal anstomoses in patients with patent arteries were 43% and 48%, respectively (P = .10). CONCLUSIONS In the presence of hepatic artery disease there is a lower patency of anastomotic biliary strictures after balloon dilation. Imaging of the hepatic artery should be considered to stratify patients who will have a successful outcome.

Calcium Binding by Radiopaque Media

This study quantified the binding of ionic calcium by contrast media with disodium edetate and trisodium citrate versus those with only calcium disodium edetate. First, calcium binding by sodium diatrizoate with calcium disodium edetate was measured using an ion-selective electrode at ionic strengths of .08, .16, and .80 molal. Significant binding of calcium was observed, and the probable reaction product is calcium chloride diatrizoate. Second, solutions were mixed containing Renografin 76 (or Hypaque 76) and NaCl at a physiologic ionic strength. The Renografin, which contains disodium edetate and trisodium citrate, caused significantly more binding than did the Hypaque. However, 60% of the drop in ionic calcium was observed with Hypaque and is related to the diatrizoate anion. The nonionic agent iopamidol produced no decrease in ionic calcium. Significant reductions in ionic calcium are produced by both the diatrizoate anion and by edetate and citrate additives.

Catheter Thrombolysis of Thrombosed Hepatic Arteries in Liver Transplant Recipients: Predictors of Success and Role of Thrombolysis

Hepatic artery thrombosis is an uncommon complication of liver transplantation. However, it is a major indication for re-transplantation. The use of transcatheter thrombolysis and subsequent surgical revascularization as a graft salvage procedure is discussed. Four of 5 cases (80%) were successful in re-establishing flow and uncovering underlying arterial anatomic defects. None were treated definitively by endoluminal measures due to an inability to resolve the underlying anatomic defects. However, 2 of 5 cases (40%) went on to a successful surgical revascularization and represent successful long-term outcome of transcatheter thrombolysis followed by definitive surgical revascularization. We conclude that, definitive endoluminal success cannot be achieved without resolving associated, and possibly instigating, underlying arterial anatomical defects. However, reestablishing flow to the graft can unmask underlying lesions as well as asses surrounding vasculature thus providing anatomical information for a more elective, better planned and definitive surgical revision.

Arc of Buhler: Incidence and Diameter in Asymptomatic Individuals

The purpose of this study was to determine the incidence and diameter of the Arc of Buhler by power injection digital subtraction angiography in asymptomatic patients. A retrospective evaluation of 120 combined celiac (CAx) and superior mesenteric artery (SMA) angiograms was carried out on potential live related liver transplant donors (asymptomatic patients) performed from January 1999 to May 2002. The diameter of the Arc of Buhler was calculated with reference to the 5 French catheters used to perform the diagnostic angiograms. It was considered hemodynamically significant if it preferential filled the branches of the other visceral vessel. An Arc of Buhler was identified in 4 patients (3.3%). All 4 patients had a patent gastroduodenal artery (GDA) and none of the 4 had a hemodynamically significant stenosis of either the SMA or the CAx. All Arcs of Buhler found measured less than 2.5 mm in diameter and half of them (2 of the 4) filled the CAx when power injecting the SMA and/or vice versa. There is a low incidence of Arc of Buhler in asymptomatic patients; however, 50% of those encountered were hemodynamically significant. When evaluating the Arc of Buhler by angiography in the setting of pathology, it is important to have a reference diameter and hemodynamic reference in the normal setting, particularly when the prospect of GDA ligation or embolization is entertained in the presence of CAx or SMA occlusion.

Renal handling and physiologic effects of the paramagnetic contrast medium, gadolinium-DOTA

Gadolinium DOTA (Gd-DOTA) is a magnetic resonance (MR) contrast agent similar to Gd-DTPA but with greater stability in vitro. The effects of a high intravenous dose (0.5 mmol/kg) of Gd-DOTA (1360 mOsm/kg) on renal excretory function and its general systemic effects are examined in this animal study. This dose was selected to accentuate and better define the qualitative nature of these effects. A decrease in arterial pressure of 8% (131.9 +/- 6.8 at 120 minutes versus a control of 142.8 +/- 3.7 mm Hg, mean +/- standard error of mean, no significant change in electrocardiogram (ECG) lead II, a 16% increase in renal blood flow (106.0 +/- 5.4 at 7.5 minutes versus 91.2 +/- 3.2 ml/min), and a decrease in arterial hematocrit of 9% (38.9 +/- 1.5 at 120 minutes versus 41.9% +/- 1.7%) were noted. In general, qualitatively similar effects have been noted as a nonspecific effect of other hyperosmolar solutions. The filtration fraction decreased (0.23 +/- 0.01 at 7.5 minutes versus 0.28 +/- 0.02) followed by a rapid return to baseline values. No significant change was noted in glomerular filtration rate throughout the experimental protocol. Urine flow increased nearly 1.5-fold and osmolal clearance (Cosm) increased approximately 1.5 times. A natriuresis occurred as the fractional excretion of sodium (FENa+) increased from a control value of 3.5 +/- 0.3 to 5.2 +/- 0.5 at 7.5 minutes. The systemic and renal physiologic effects of high-dose intravenous Gd-DOTA on the kidney reflects a nonspecific, osmotically induced alteration. These data suggest that the main systemic and renal physiologic actions of Gd-DOTA are a nonspecific response to agent osmolality that is similar qualitatively to conventional, water-soluble contrast media.

Endoluminal Management of Arterioportal Fistulae in Liver Transplant Recipients: A Single-Center Experience

Transcatheter embolization of arterioportal fistulae in liver transplant recipients is restricted to symptomatic arterioportal fistulae. Angiograms of liver transplant recipients from a single university medical center were retrospectively reviewed. Hemodynamically significant arterioportal fistulae were defined as those exhibiting opacification of the main portal vein of the transplanted hepatic graft or its first order branch with or without portal venous changes by Doppler ultrasound imaging. Six arterioportal fistulae were found. Doppler ultrasound imaging detected 50% of all arterioportal fistulae and all 3 hemodynamically significant arterioportal fistulae. Three successful embolizations were performed. Follow-up (37 to 67 months) demonstrated patent hepatic arteries and no parenchymal ischemic changes with graft preservation. High-throughput arterioportal fistulae may require larger intrahepatic artery branch embolization. There is a window of opportunity for embolizing significant arterioportal fistulae before their progression to large symptomatic, high through-put arterioportal fistulae with their added risk of ischemic changes before and after embolization.

Comparison of vasa vasorum after intravascular stent placement with sirolimis drug-eluting and bare metal stents

The cytostatic drug, sirolimis has shown prevention in neointimal hyperplasia after stent placement. Recent studies have shown persistent inflammation seen with drug‐eluting stents (DES) may result in late stent thrombosis. The aim of this study is to compare effects of bare metal stents (BMS) and sirolimis DES on the neointima and vasa vasorum in stented rabbit aortas. Stents were implanted in eight New Zealand rabbits for 9 weeks. Group I rabbits received BMS. Group II rabbits received sirolimis DES. A balloon‐mounted BMS or DES was placed in the infrarenal aorta. Following euthanasia, aortas were perfused with barium sulfate and sectioned for histology. After 9 weeks the qualitative intrastent luminal diameter was fairly uniform in both the DES and the BMS. The thickness of neointima was similar in both groups. The number of vasa vasorum in the sirolimis DES increased compared with the BMS (P < 0.05). An increased number of vasa vasorum produced by the DES when compared with the BMS shows a difference in response to local vessel injury in rabbits. This result suggests that vasa vasorum may play a role in the persistent inflammation generated by sirolimis‐coated stents.

Transjugular intrahepatic portosystemic shunt in a living donor left lateral segment liver transplant recipient: technical considerations.

The technical aspects of placing transjugular intrahepatic portosystemic shunts (TIPS) in liver transplant recipients with full allografts have well been described. In the era of live related hepatic donors, and the growing population of their recipients, it is likely that TIPS shunts will be placed in failing transplant lobes/segments. Growing allografts that are initially undersized can have an unconventional orientation of the hepatic and portal veins, which may also change with remodeling and rotation of the graft during their growth. The authors review the technical differences for TIPS procedures in transplants, particularly split grafts. They describe a technically successful TIPS procedure in an undersized and remodeled left lateral segment liver recipient and the additional difficulty this may pose.