Segmental liver ischemia/infarction after elective transjugular intrahepatic portosystemic shunt creation: clinical outcomes in 10 patients.

PURPOSE: To determine the clinical significance and potential mechanisms of segmental liver ischemia and infarction following elective creation of a transjugular intrahepatic portosystemic shunt (TIPS). MATERIALS AND METHODS: A retrospective review of 374 elective TIPS creations between March 2006 and September 2014 was performed, yielding 77 contrast-enhanced scans for review. Patients with imaging evidence of segmental perfusion defects were identified. Model for End-stage Liver Disease scores, liver volume, and percentage of liver ischemia/infarct were calculated. Clinical outcomes after TIPS creation were reviewed. RESULTS: Ten patients showed segmental liver ischemia/infarction on contrast-enhanced imaging after elective TIPS creation. Associated imaging findings included thrombosis of the posterior division (n = 7) and anterior division (n = 3) of the right portal vein (PV). The right hepatic vein was thrombosed in 5 patients, as was the middle hepatic vein in 3 and the left hepatic vein in 1. One patient had acute thrombosis of the shunt and main PV. Three patients developed acute liver failure: 2 died within 30 days and 1 required emergent liver transplantation. One patient died of acute renal failure 20 days after TIPS creation. A large infarct in a transplant recipient resulted in biloma formation. Five patients survived without additional interventions with follow-up times ranging from 3 months to 5 years. CONCLUSIONS: Segmental perfusion defects are not an uncommon imaging finding after elective TIPS creation. Segmental ischemia was associated with thrombosis of major branches of the PVs and often of the hepatic veins. Clinical outcomes varied significantly, from transient problems to acute liver failure with high mortality rates.

Superior vena cava (SVC) filters placed over central lines - analysis of line trapping and difficulties with line retrieval: an in-vitro experimental study.

BACKGROUND: Placement of superior vena cava (SVC) filters has been shown to be both safe and effective in preventing symptomatic pulmonary embolism in patients with upper extremity deep venous thrombosis that have contraindications to anticoagulation therapy. In many patients, existing central lines pose a challenge to SVC filter placement due to the theoretical risk of line displacement and/or entrapment. PURPOSE: To assess the risk of catheter entrapment by filter legs during SVC filter deployment and the risk of subsequent filter migration during catheter removal. MATERIAL AND METHODS: A model was created by placing a 22 mm vascular graft inside a plastic tube and submerged in a warm saline bath. Five types of filters were deployed under fluoroscopic guidance over different types of central lines of varying calibers (5-14 Fr). Each filter was deployed five times over each type of central line. The positioning of the legs of the filters in relationship to the central lines was studied by fluoroscopic and direct inspection. The lines were then removed under fluoroscopic guidance noting any line trapping, migration, and/or tilting of the filters. RESULTS: Movement of the lines during filter expansion was commonly seen after deployment of all filters with varying frequencies. During line removal slight resistance was encountered with the Celect filter (10%) and the Option filter (5%), while significant resistance was only encountered when using the OptEase filter (20%). Filter migration was only observed when the OptEase filter was deployed over large (>10 Fr) caliber lines (10%). CONCLUSION: When SVC filters are placed over existing central lines, the risk of catheter entrapment is very low in this in-vitro model. Filter migration during line retrieval was only observed when the OptEase filter was placed over >10 Fr caliber lines.

Role of interventional procedures in obstetrics/gynecology.

In uterine fibroid embolization (UFE), knowledge of the potential ovarian-uterine anastomoses is important because they provide collateral blood flow that may result in the failure of the UFE or ovarian nontarget embolization. Uterine artery embolization is an alternative treatment of postpartum hemorrhage with 80% to 90% bleeding control and in which fertility can be preserved. Diagnosis of pelvic congestion syndrome on routine sonographic or computed tomography/magnetic resonance imaging is often missed. Fallopian tube recanalization allows couples to have unlimited attempts to conceive naturally and avoids the risks (multiple pregnancies, ovarian hyperstimulation syndrome), and high cost of in vitro fertilization.

Embolization of a large high-flow renal arteriovenous fistula using 035″ and 018″ detachable coils.

Transcatheter embolization of renal arteriovenous fistula (AVF) is a minimally invasive procedure that, in some occasions, can replace surgery and potentially save the kidney. The embolization techniques for the renal AVFs have evolved considerably with the availability of newer hardwares. Still, the risk of inadvertent migration of the embolization materials to the pulmonary circulation is a concern. This article describes a novel technique of coiling the feeding segmental artery to a large high-flow renal AVF using 035″ and 018″ detachable coils only, and briefly reviews the previously described strategies to safely embolize renal AVFs.

Traumatic occlusion and dissection of the main renal artery: endovascular treatment.

PURPOSE: To report experience with endovascular treatment of traumatic injuries of the main renal artery. MATERIALS AND METHODS: A retrospective review of traumatic injuries to the main renal artery was performed in three major trauma institutions. Eight patients (age range, 17-46 y; mean age, 27 y) presented with main renal artery occlusion (n = 7) or dissection (n = 1) after major blunt abdominal trauma. Associated injuries were present in the majority of patients. The mean time from injury to intervention was 5 hours (range, 2-8 h). RESULTS: Recanalization of the occluded renal artery with stent placement was successfully achieved in six patients. In two of the eight patients, interventions resulted in extravasation of contrast medium, and embolization of the main renal artery was performed. At follow-up 2-24 months after injury, four patients had kidney atrophy (two treated with embolization and two with stents), two had proven stent patency with functional kidneys, one was normotensive with unknown stent patency, and one was lost to follow-up. One of the patients with an occluded stent developed severe renal hypertension and required nephrectomy. CONCLUSIONS: The majority of occlusions and dissections of the main renal artery after major blunt abdominal trauma can be successfully treated with recanalization and stent placement. However, long-term kidney salvage is not always achieved, and there is a potential of development of renovascular hypertension, which may require late nephrectomy.

MRI of perfusion-diffusion mismatch in non-human primate (baboon) stroke: a preliminary report.

The goal of this study was to develop a clinically relevant non-human primate (baboon) stroke model and multi-parametric MRI protocols on a clinical scanner with long-term goals to better model human stroke and facilitate clinical translations of novel therapeutic strategies. Baboons were chosen because of their relatively large brain volume and that they are evolutionarily close to humans. Middle cerebral artery occlusion (MCAO) was induced using a minimally invasive endovascular approach to guide an inflatable balloon catheter into the MCA and followed by permanently or transiently inflate the balloon. Using multimodal MRI, including perfusion and diffusion imaging, the spatiotemporal dynamic evolution of the ischemic lesions in permanent and transient occlusion experiments in baboons were investigated. Perfusion-diffusion mismatch, which approximates the ischemic penumbra, was detected. In the permanent MCAO group (n = 2), the mean infarct volume was 29 ml (17% of total brain volume) whereas in the transient MCAO group (n = 2, 60 or 90 min of occlusion), the mean infarct volume was 15 ml (9% of total brain volume). Substantial perfusion-diffusion mismatch tissue (~50%) was salvaged by reperfusion compared to permanent MCAO. This baboon stroke model has the potential to become a translational platform to better design clinical studies, guide clinical diagnosis and improve treatment time windows in patients.

MDCT angiography of mesenteric bypass surgery for the treatment of chronic mesenteric ischemia.

OBJECTIVE: Chronic mesenteric ischemia (CMI) is a serious condition that requires surgical or endovascular intervention. Surgical revascularization for the treatment of CMI uses different operative techniques including endarterectomy, vessel reimplantation, and mesenteric bypass. A basic understanding of the operative techniques is essential for the adequate interpretation of imaging studies in patients who have undergone surgery for CMI. In this article, we review the different operative techniques used in the treatment of CMI, discuss the results of surgical intervention for CMI, and illustrate how MDCT angiography (MDCTA) can be used for follow-up and for the detection of early and late complications after surgery. CONCLUSION: MDCTA is a powerful tool for the postoperative evaluation of patients with CMI. Early detection of graft dysfunction is critical to prevent graft occlusion and the development of potentially fatal mesenteric ischemia. MDCTA can detect early and late complications after surgery and guide additional surgical or endovascular interventions.

Transjugular intrahepatic portosystemic shunt flow reduction with adjustable polytetrafluoroethylene-covered balloon-expandable stents.

Creation of a transjugular intrahepatic portosystemic shunt (TIPS) can effectively treat complications of portal hypertension, but excessive shunting can cause life-threatening hepatic encephalopathy and hepatic insufficiency. The present report describes a novel technique that allows for controlled and adjustable flow reduction through the TIPS via partial closure of the shunt with a balloon-mounted covered stent. The method results in clinical improvement of hepatic encephalopathy and hepatic insufficiency and immediate increase in the portosystemic pressure gradient. However, among the four patients described herein, survival beyond 1 year was seen in only one, who underwent liver transplantation after TIPS reduction.

Causes of TIPS dysfunction.

OBJECTIVE: Transjugular intrahepatic portosystemic shunt (TIPS) creation is an effective method to control portal hypertension. TIPS creations with bare stents have shown limited and unpredictable patency. In nearly all cases of rebleeding or recurrent ascites after TIPS creation, there is shunt stenosis or occlusion. The purpose of this article is to review the biologic and technical factors that predispose to TIPS failure and how the use of an expandable polytetrafluoroethylene (PTFE)-covered-stent has significantly improved TIPS patency. CONCLUSION: Biologic and technical factors may predispose to shunt failure. The combination of improved technique and expandable PTFE has significantly improved TIPS patency. The need for follow-up venography and secondary interventions has been reduced significantly as a result of improved shunt patency.

Crural artery traumatic injuries: treatment with embolization.

The purpose of this paper is to report our experience with the endovascular treatment of crural arterial injuries using transcatheter and direct embolization techniques. A total of eight consecutive patients have been treated during a 7-year period. Six males and two females, mean age 32 years (range, 15-56 years), presented with penetrating trauma to the lower extremities. Mechanisms of injuries were stab wounds in six patients, gun shot wound in one patient, and iatrogenic injury in one patient. Five patients presented with acute trauma, while three patients presented with delayed injuries. Crural arterial injuries encountered included pseudoaneurysms with arteriovenous fistulas (n = 6), pseudoaneurysms with vessel transections (n = 2), and pseudoaneurysm (n = 1). Proximal and distal embolization with coils was used in three cases, proximal embolization with coils in three cases, percutaneous thrombin injection in one case, and liquid n-butyl cyanoacrylate in one case. Complete exclusion of the lesions was accomplished by sacrifice of one crural vessel in seven cases and of two crural vessels in one case. Two cases of delayed injuries required combined coil and liquid embolization techniques for lesion exclusion. A minor complication (groin hematoma) occurred in one patient, no distal ischemia was seen, and no amputations were required. Mean follow-up was 61 days (range, 1-180 days). One pseudoaneurysm treated with thrombin injection recurred and required surgical excision. We conclude that transcatheter embolization alone or in combination with different endovascular techniques is useful in the treatment of traumatic crural vessel injuries.