Jai V. Patel

Initial Clinical Experience Using the Amplatzer Vascular Plug

Background and purposeThe Amplatzer Vascular Plug (AVP) is a self-expanding nitinol wire mesh vascular embolization device derived from the Amplatz septal occluder. We assessed the results of vascular embolization obtained using the AVP.MethodsA retrospective review was carried out of 23 consecutive cases of vascular embolization using the AVP in a variety of different clinical settings. The AVP was chosen to have a diameter approximately 30–50% greater than the target vessel. The device was delivered via an appropriately sized guide catheter and was released when satisfactorily positioned. Additional embolic agents were used in some cases.ResultsAll target vessels were successfully occluded with no device malpositioning or malfunction. In 14 (61%) patients the AVP was the sole embolic material. In the remaining patients additional agents were used, particularly in preoperative embolization of highly vascular renal tumors. The AVP does not cause instantaneous thrombosis and in high-flow situations thrombosis typically takes up to 15 min.ConclusionThe AVP is a safe, effective embolization device that provides a useful adjunct to the therapeutic armamentarium. It is particularly suited to the treatment of short high-flow vessels where coil migration and catheter dislodgment might occur. In the majority of cases no additional embolic agents are necessary but it may take up to 15 min for complete thrombosis to occur.

Hepatic artery pseudoaneurysm after liver transplantation: treatment with percutaneous thrombin injection.

Pseudoaneurysms of the hepatic artery are a rare complication of liver transplantation. Early diagnosis and treatment are essential to avoid life-threatening hemorrhage. Conventional treatment consists of surgical resection and vascular reconstruction or transarterial coil embolization. More recently, percutaneous thrombin injection has been successfully used in the treatment of femoral artery pseudoaneurysms. We describe a 70-year-old woman who had a hepatic artery pseudoaneurysm after orthotopic liver transplantation, which was successfully treated by percutaneous thrombin injection.

Endovascular Treatment of Visceral Aneurysms Associated with Pancreatitis and a Suggested Classification with Therapeutic Implications

PURPOSE To describe a 10-year experience of endovascular and percutaneous treatment of aneurysms and pseudoaneurysms complicating pancreatitis, and to analyze this experience and propose a classification based on computed tomography (CT) and angiographic findings that has therapeutic implications. This may reduce the rate of recurrent bleeding after surgery or endovascular treatment. MATERIALS AND METHODS Twenty-three patients with aneurysms or pseudoaneurysms associated with acute pancreatitis were treated by endovascular or percutaneous methods. All underwent CT and angiography. The early development of a simple classification based on the CT and angiographic findings was used to guide treatment decisions. In accordance with this classification, 19 patients were treated by primary coil embolization and four were treated by primary percutaneous thrombin injection. RESULTS Among the 19 patients treated by primary coil embolization, there were two early recurrences of the pseudoaneurysm. All four patients treated by percutaneous thrombin injection exhibited late recurrences and were successfully treated by percutaneous thrombin injections. Twenty-one patients (91.3%) were alive at 6 months. CONCLUSIONS Endovascular and percutaneous treatment of aneurysms and pseudoaneurysms complicating pancreatitis is safe and effective and is associated with good outcomes, but careful follow-up is necessary. The decision of which treatment option is most appropriate can be made in accordance with a classification based on CT and angiographic appearance.

Hemorrhagic Complications After Whipple Surgery: Imaging and Radiologic Intervention

OBJECTIVE The aim of this pictorial essay is to illustrate the radiologic patterns, sites of bleeding, and vascular interventional techniques used in the management of postpancreatectomy hemorrhage. CONCLUSION Hemorrhagic complications occur in fewer than 10% of patients after Whipple pancreatoduodenectomy but account for as many as 38% of deaths. Bleeding typically occurs from the stump of the gastroduodenal artery, but other sites of bleeding are increasingly recognized.

Assessment of Apparent Internal Carotid Occlusion on Ultrasound: Prospective Comparison of Contrast-enhanced Ultrasound, Magnetic Resonance Angiography and Digital Subtraction Angiography

OBJECTIVES Modern conventional ultrasound is sensitive to slow flow, but may misclassify some tight stenoses as occlusion. Symptomatic patients with tight proximal internal carotid artery stenoses may benefit from carotid endarterectomy but those with occlusion or long-segment disease do not. DESIGN A prospective study of the diagnostic accuracy of contrast-enhanced ultrasound (CE-US), 2D time-of-flight magnetic resonance angiography (2D-TOF MRA) and contrast-enhanced magnetic resonance angiography (CE-MRA) against a reference standard of digital subtraction angiography (DSA) in patients with apparent carotid occlusion on conventional ultrasound. MATERIALS AND METHODS Thirty-one patients with apparent carotid occlusion on conventional ultrasound and with recent ispilateral hemispheric transient ischaemeic attacks (TIAs) were studied. The primary endpoint was confirmation of occlusion with a secondary endpoint of identification of a surgically correctible lesion. RESULTS The sensitivity and specificity of CE-US, 2D-TOF MRA and CE-MRA for patency were 1 & 1, 0.33 & 1 and 0.6 & 1 respectively and for the detection of a surgically correctible lesion were 1 & 0.96, 0.67 & 1 and 1 and 0.96 respectively. CE-US was difficult to interpret, precluding confident diagnosis in 5 cases. CONCLUSIONS 2D-TOF MRA had poor sensitivity for patency and cannot be recommended as a second-line investigation to assess vessels apparently occluded on conventional ultrasound. Confident diagnosis on CE-US and CE-MRA accurately identified occlusion. If occlusion is confirmed by either of these modalities, no further imaging is required. The relative advantages of CE-US or CE-MRA in this situation are uncertain.

Preoperative imaging of left portal vein at the Rex recess for Rex shunt formation using wedged hepatic vein carbon dioxide portography.

BACKGROUND In children with extrahepatic portal vein obstruction (EHPVO), formation of a mesentericoportal bypass (Rex shunt) restores hepatopetal flow, relieves portal hypertension, and reduces variceal bleeding and hypersplenism. The Rex shunt is created by inserting a vein graft between the superior mesenteric vein and the umbilical segment (Rex) of the left portal vein within the Rex recess of the liver. The preoperative evaluation of a patient with EHPVO includes an accurate assessment of the venous inflow and outflow. The inflow portal vein is readily assessed by ultrasound and magnetic resonance imaging. The outflow intrahepatic portal vein is harder to assess. We report our experience of patients evaluated with wedged hepatic vein carbon dioxide portography (WHVCP). METHOD All children referred for venography from October 2001 to October 2007 were prospectively identified, and clinical and radiologic data were reviewed retrospectively. The imaging findings were correlated to findings at surgery. RESULTS Eleven children (range, 3-14 years, median, 6 years) were referred for preoperative wedged hepatic venography. The left portal vein at the Rex recess was clearly identified in 9 patients (82%). In the other 2 patients (18%), the Rex segment was not identified despite opacification of left and right intrahepatic portal veins; this was taken to indicate an occluded segment. Wedged venography was performed with carbon dioxide in 10 patients (91%). Carbon dioxide was contraindicated in the final patient because of the presence of a ventricular septal defect. CONCLUSION Our series demonstrates the use of WHVCP as a diagnostic tool in preoperative assessment of the Rex segment of left portal vein in children with extrahepatic portal vein obstruction.

Calcium channel blockers enhance sac shrinkage after endovascular aneurysm repair

OBJECTIVE Sac shrinkage is a surrogate marker of success after endovascular aneurysm repair (EVAR). We set out to determine if any common cardioprotective medications had a beneficial effect on sac shrinkage. METHODS This retrospective observational study took place at Leeds Vascular Institute, a tertiary vascular unit in the Northern United Kingdom. The cohort comprised 149 patients undergoing EVAR between January 1, 2005, and December 31, 2008. Medication use was recorded at intervention (verified at study completion in 33 patients), and patients were monitored for 2 years. The main outcome measures were the effect of medication on sac shrinkage as determined by percentage change in maximal idealized cross-sectional area of the aneurysm at 1 month, 6 months, 1 year, and 2 years by linear regression model, in addition to 2-year endoleak and death rates determined by a binary logistic regression model. RESULTS After exclusions, 112 patients, who were a median age of 78 years (interquartile range, 78-83 years), remained for analysis. The median Glasgow Aneurysm Score was 85 (interquartile range, 79-92). At 2 years, mortality was 13.4%, endoleak developed in 37.5%, and significant endoleak developed in 14.3%. Patients taking a calcium channel blocker had enhanced sac shrinkage, compared with those not taking a calcium channel blocker, by 6.6% at 6 months (-3.0% to 16.3%, P = .09), 12.3% at 1 year (2.9% to 21.7%, P = .008), and 13.1% at 2 years (0.005% to 26.2%, P = .007) independent of other medication use, graft type, endoleak development, or death. CONCLUSIONS Enhanced sac shrinkage occurred after EVAR in patients taking calcium channel blockers. This warrants further study in other centers and at the molecular level.

Ischemic Skin Ulceration Complicating Glue Embolization of Type II Endoleak after Endovascular Aneurysm Repair

The optimal treatment for type II endoleaks remains unclear. The present report describes a case of ischemic skin ulceration after glue embolization of a type II endoleak with challenging access in a multiply comorbid 82-year-old woman with an expanding aneurysm sac 3 years after endovascular aneurysm repair. Embolization was performed from a proximal position with an n-butyl cyanoacrylate/Ethiodol mixture to allow flow into the endoleak because direct sac puncture was hazardous. One week after intervention, an eschar, which progressed to superficial necrosis as a result of partial nontarget delivery of sclerosant, developed over the left iliac crest. The eschar was self-limiting, with complete resolution by 6 months.

Endovascular management of arterial conduit pseudoaneurysm after liver transplantation: a report of two cases.

We describe two cases of pseudoaneurysms in liver-transplant iliac artery conduits, which were successfully treated with endovascular stent grafting.

Routine chest radiography following imaging-guided placement of tunneled central lines: a waste of time, money, and radiation.

BACKGROUND This study sought to evaluate routine chest radiography following placement of tunneled central lines using combined ultrasound and fluoroscopic guidance. MATERIALS AND METHODS A prospective study of 150 consecutive patients who underwent placement of tunneled central lines in the vascular radiology suite. Ultrasound-guided vein puncture was performed with an 18-gauge needle in each case, and the access site was noted. Line position was confirmed by fluoroscopy. Following the procedure, 50 patients had both an on-table digital chest radiograph and a conventional chest radiograph. Subsequent patients had a digital radiograph and a fluoroscopic image grab. Final line tip position was scored, and complications were recorded. RESULTS Line placement was optimal (95%) or acceptable (5%) in all patients. Line tip position could be satisfactorily evaluated on supine fluoroscopy. Mean fluoroscopic x-ray dose was 0.5 cGy/cm2. Digital chest x-ray dose was 9.0 cGy/cm2, and formal chest radiography dose was 12.0 cGy/cm2. The only complications were 2 carotid artery punctures without clinical sequelae. CONCLUSION When lines are placed under imaging guidance with ultrasound to direct the venous puncture, complications are rare and are not likely to be clinically important. Conventional and digital chest radiographs do not contribute clinically relevant information but do add to the radiation dose, time, and expense of the procedure.