Ralph Jackson

Results of a Retrospective Multicenter Trial of the Viatorr Expanded Polytetrafluoroethylene– covered Stent-Graft for Transjugular Intrahepatic Portosystemic Shunt Creation

PURPOSE To report the results of a multicenter experience with the Viatorr expanded polytetrafluoroethylene-covered stent-graft for transjugular intrahepatic portosystemic shunt (TIPS) creation in which patency and clinical outcome were evaluated. MATERIALS AND METHODS One hundred consecutive patients with portal hypertension, with a mean age of 52 years (range, 22-86 years), underwent implantation of the Viatorr TIPS stent-graft at one of three hospital centers. The indications for TIPS creation were variceal bleeding (n = 81) and refractory ascites (n = 19). Twenty patients had Child-Pugh class A disease, 46 had class B disease, and 34 had class C disease. Eighty-seven patients underwent de novo TIPS placements, with 13 treated for recurrent TIPS stenosis. Sixty-two patients were available for follow-up portal venography and portosystemic pressure gradient (PSG) measurement commencing 6 months after Viatorr stent-graft placement. RESULTS The technical success rate was 100%. TIPS creation resulted in an immediate decrease in mean PSG (+/-SD) from 21 mm Hg +/- 6 to 7 mm Hg +/- 3. Acute repeat intervention (within 30 days) was required for portal vein thrombosis (n = 1), continued bleeding (n = 3), and encephalopathy (n = 1). The all-cause 30-day mortality rate was 12%. Two patients developed acute severe refractory encephalopathy, which led to death in one case. New or worsening encephalopathy was identified in 14% of patients. The incidence of recurrent bleeding was 8%. The cumulative survival rate at 1 year was 65%. Sixty-two patients available for venographic follow-up had a mean PSG of 9 mm Hg +/- 5 at a mean interval of 343 days (range, 56-967 days). There were four stent-graft occlusions (6%) and seven hemodynamically significant stenoses (11%), four within the stent-graft and three in the non-stent-implanted hepatic vein. The primary patency rate at 1 year by Kaplan-Meier analysis was 84%. CONCLUSIONS This retrospective multicenter experience with the Viatorr stent-graft confirms the preliminary findings of other investigators of good technical results and improved patency compared with bare stents. Early mortality and symptomatic recurrence rates are low by historical standards. The theoretical increase in TIPS-related encephalopathy was not demonstrated. Longer-term follow-up will be required to determine whether the additional cost of the Viatorr stent-graft will be offset by reduced surveillance and repeat intervention.

Folic acid handling by the human gut: implications for food fortification and supplementation

Background: Current thinking, which is based mainly on rodent studies, is that physiologic doses of folic acid (pterylmonoglutamic acid), such as dietary vitamin folates, are biotransformed in the intestinal mucosa and transferred to the portal vein as the natural circulating plasma folate, 5-methyltetrahydrofolic acid (5-MTHF) before entering the liver and the wider systemic blood supply. Objective: We tested the assumption that, in humans, folic acid is biotransformed (reduced and methylated) to 5-MTHF in the intestinal mucosa. Design: We conducted a crossover study in which we sampled portal and peripheral veins for labeled folate concentrations after oral ingestion with physiologic doses of stable-isotope–labeled folic acid or the reduced folate 5-formyltetrahydrofolic acid (5-FormylTHF) in 6 subjects with a transjugular intrahepatic porto systemic shunt (TIPSS) in situ. The TIPSS allowed blood samples to be taken from the portal vein. Results: Fifteen minutes after a dose of folic acid, 80 ± 12% of labeled folate in the hepatic portal vein was unmodified folic acid. In contrast, after a dose of labeled 5-FormylTHF, only 4 ± 18% of labeled folate in the portal vein was unmodified 5-FormylTHF, and the rest had been converted to 5-MTHF after 15 min (postdose). Conclusions: The human gut appears to have a very efficient capacity to convert reduced dietary folates to 5-MTHF but limited ability to reduce folic acid. Therefore, large amounts of unmodified folic acid in the portal vein are probably attributable to an extremely limited mucosal cell dihydrofolate reductase (DHFR) capacity that is necessary to produce tetrahydrofolic acid before sequential methylation to 5-MTHF. This process would suggest that humans are reliant on the liver for folic acid reduction even though it has a low and highly variable DHFR activity. Therefore, chronic liver exposure to folic acid in humans may induce saturation, which would possibly explain reports of systemic circulation of unmetabolized folic acid. This trial was registered at clinicaltrials.gov as NCT02135393.

The Renal Impact of Aortic Stent-Grafting in Patients with a Horseshoe Kidney

Aortic stent grafting may be an alternative to surgery for patients with an abdominal aortic aneurysm and coexistent horseshoe kidney but is not without difficulties. This study examines the renal consequences of aortic stent grafting in such patients. This is a retrospective review of patients with horseshoe kidney in whom aortic stent grafting was performed between December 1995 and August 2000. Follow-up occurred within the EUROSTAR protocol and included measurement of serum creatinine. Of 130 patients in whom aortic stent grafting was performed, 4 had coexistent horseshoe kidney. In all patients the aneurysm was successfully excluded with the occlusion of between one and four anomalous renal arteries. At follow-up, no clinically significant renal impairment was detected. Endovascular aneurysm repair is an attractive option for patients with a horseshoe kidney and normal preoperative creatinine levels.

Multicenter Safety and Efficacy Analysis of Assisted Closure after Antegrade Arterial Punctures Using the StarClose Device

Purpose: To evaluate the safety and efficacy of the StarClose device for closure of antegrade punctures following infrainguinal endovascular interventions. Methods: A retrospective review was conducted of 221 consecutive patients treated with the StarClose device in a 12-month period at 5 centers (4 French and 1 British). Of these, 107 patients (69 men; median age 75 years, range 44–93) were from the UK cohort (111 closures), and 94 patients (75 men; median age 67 years, range 32–95) were from the French cohort (111 closures). Technical success, complication rates, demographic data, medical history, and procedural details were gathered for all patients. Residual bleeding and the requirement for additional manual compression were recorded when the device failed. Clinical evaluation was performed at discharge; color-coded duplex ultrasonography was done in a subset of French patients. Results: The overall technical success rate was 94.6% (210/222; 95% CI 3.1%–9.2%). The results were similar in the 2 cohorts: 95.5% (106/111; 95% CI 1.9%–10.1%) in the UK and 93.7% (104/111; 95% CI 3.1%–12.4%) in France. The 12 failures (5 UK and 7 France) were due to several mechanisms: device failure (n=5), obesity (n=1), groin scarring (n=2), and unexplained (n=4). In 2 failed cases, open surgical closure of the arteriotomy was performed because pressure hemostasis failed. Two pseudoaneurysms were observed: one after immediate failure was successfully treated by prolonged pressure; the other, after apparent success of the device, required surgical therapy. The incidence of serious vascular complication was 1.8% (4/222; 95% CI 0.7%–4.5%); 2 patients from each cohort. Conclusion: The StarClose device safely and effectively closes antegrade punctures after infrainguinal endovascular intervention, even in patients who would be considered to be at high risk for puncture-site bleeding. However, a randomized trial would be required to support any definitive recommendations.

Percutaneous ablation of an internal iliac aneurysm using tissue adhesive

We report the percutaneous injection of tissue adhesive (Tisseal, Immuno, Vienna, Austria) to ablate a 12-cm internal iliac aneurysm. The complex history of this lesion included previous surgery for a ruptured aortic aneurysm, attempted repair of the internal iliac aneurysm, and several embolization procedures. These factors precluded further open repair or transcatheter techniques and dictated the choice of a more direct approach.

Use of a multilayered stent for the treatment of hepatic artery pseudoaneurysm after liver transplantation.

To the Editor: We would like to use this opportunity to share with the wider clinical community our experience in managing a hepatic artery pseudoaneurysm (HAP) of a 59-year-old man after liver transplant using a multilayered stent. HAP is a rare but well-recognised complication occurring after orthotopic liver transplantation (OLT). The reported incidence is 0.3% to 2.6% [1, 2]. The majority of cases of HAP occurring after OLT arise in the context of endovascular intervention or secondary to diathermy injury to the artery during surgery [3]. They have also been reported to complicate other hepato-pancreatico-biliary surgical procedures [4]. With time, the natural history of HAP is of enlargement and an associated risk of rupture, which can be fatal [5]. Patients most commonly present with intraperitoneal bleeding or gastrointestinal haemorrhage secondary to haemobilia; however, incidental and asymptomatic HAP may be recognised [6]. Established management options include surgical ligation and endovascular coil embolisation; however, both of these methods are associated with a significant risk of hepatic ischaemia, which often requires retransplantation [5]. Coronary artery stent-grafts have also been used to treat HAP, often after failure of coil embolisation [7]. The introduction of the Multilayer Aneurysm Repair System (MARS) stent (Cardiatis SA, Belgium) is a recent development in endovascular aneurysm repair. This is an uncovered stent comprised of three-dimensional braided tubing that decreases blood flow velocity in the aneurysmal sac whilst improving laminar blood flow in the main artery and surrounding arterial tributaries [8]. Its use for the treatment of HAP occurring after OLT has not previously been reported. Our case involves a 59 year-old man who underwent OLT for alcoholic cirrhosis in January 2011. The patient’s main indication for OLT was recurrent ascites. A transjugular intrahepatic portosystemic shunt was inserted in November 2010 before emergency surgical repair of a ruptured umbilical hernia. He was transplanted in early January 2011. He received a whole liver from a 74-year-old brainstem-dead donor who was involved in a road-traffic accident. His hepatectomy was performed whilst he was on veno-venous bypass and was uncomplicated. The implantation included a cavocavostomy, end-to-end pulmonary vein anastomosis using 5.0 Prolene (Ethicon, UK) suture material, end-to-end arterial anastomosis to the common hepatic artery using 6.0 Prolene (Ethicon, UK) suture material, and duct-to-duct biliary anastomosis using 5.0 polydioxanone (Ethicon, UK) suture material. The cold ischaemic time was 12 h and 40 min. During surgery, he received 4 U of blood, 1 pool of platelets, and 6 U of fresh frozen plasma. His postoperative recovery was complicated by mild acute cellular rejection on day 10, which required augmentation with intravenous methylprednisolone. He was discharged home on day 16. His immunosuppression medication included tacrolimus, azathioprine, and prednisolone. Because he was a cytomegalovirus mismatch, vanganciclovir was given for 100 days. At 3 months after OLT, the patient was admitted to our hospital for investigation of graft dysfunction. Liver histology showed evidence of perivenular haemorrhage and A. M. Elsharkawy (&) G. Sen M. Hudson S. Masson D. M. Manas Liver Unit, Freeman Hospital, Freeman Road, Newcastle Upon Tyne NE7 7DN, UK e-mail: ahmede@doctors.org.uk

Multicenter retrospective investigation into migration of fenestrated aortic stent grafts

OBJECTIVE Fenestrated stent grafts are subject to the same hemodynamic forces that have resulted in migration of standard infrarenal stent grafts. Outcome data for fenestrated endovascular aneurysm repair consist of short-term and midterm efficacy studies where migration was generally poorly investigated. This study investigated the migration of fenestrated stent grafts in patients treated by fenestrated endovascular aneurysm repair in the United Kingdom. METHODS A total of 154 patients were retrospectively enrolled from nine sites across the United Kingdom. Patients had been treated with a Zenith fenestrated endograft (Cook Medical, Bloomington, Ind) between 2003 and 2010. Patients were required to have a baseline (first) postoperative computed tomography (CT) scan and at least one additional CT scan available. Measurements from the proximal stent graft to the superior mesenteric artery and from the distal stent graft to the iliac bifurcation were performed on the first postoperative CT scan. These measurements were repeated on all subsequent CT scans, and differences between the baseline and subsequent CT scans for the same anatomical location were suggestive of device migration. Migration was defined as cranial (-) or caudal (+) movement of the stent graft of ≥4 mm. RESULTS Proximal migration (median, +6.0 mm; range, +4.1 to +10.0 mm) was evident in 33 patients (21%). The probability of being free from proximal migration at 12, 24, and 36 months was estimated as 82% (95% confidence interval [CI], 75%-89%), 77% (95% CI, 70%-85%), and 77% (95% CI, 70%-85%), respectively. Of 259 limbs assessed, 34 (13%) showed evidence of cranial migration (median, -6.1 mm; range, -21.3 to -4.1 mm). The observed probability of being free from any iliac limb migration at 12, 24, and 36 months was 85% (95% CI, 79%-92%), 82% (95% CI, 75%-90%), and 65% (95% CI, 52%-80%), respectively. CONCLUSIONS Proximal migration occurs in approximately one-third of patients by 4 years, all migration was caudal in direction, with 60% <6.0 mm in length. Clinical sequelae were infrequent, with no statistically significant differences in the number of complications or reinterventions in patients with and without proximal migration.

Descending Thoracic Endovascular Aneurysm Repair: Antegrade Approach via Ascending Aortic Conduit

Challenging access situations continue to arise in endovascular aneurysm repair, despite evolving arterial access techniques. We report a modified access approach, where an ascending aortic conduit was successfully used for antegrade delivery of a thoracic endograft to repair a descending thoracic aortic aneurysm, in a patient with previous surgical ligation of the infra-renal aorta.

Use of the profunda femoris to facilitate closure of an antegrade puncture with the StarClose device after proximal SFA angioplasty.

Purpose: To report a novel technique for safely closing antegrade common femoral artery (CFA) punctures using the StarClose device after proximal superficial femoral artery (SFA) angioplasty. Technique: The vessel locator of the StarClose device should not be deployed within a recently dilated vessel, so after proximal SFA angioplasty, the sheath is withdrawn into the CFA. A second guidewire is inserted into the profunda femoris artery followed by insertion of the StarClose sheath. The vessel locator is deployed in the profunda main stem and withdrawn into the CFA until resistance is felt, indicating apposition to the luminal aspect of the vessel wall. The device is subsequently deployed according to the manufacturers instructions. Conclusion: Use of profunda femoris artery allows safe closure of the CFA using the StarClose device following antegrade puncture for proximal SFA angioplasty.

Endovascular Repair of Iliac, Visceral and False Aneurysms

This chapter has focussed on endovascular treatment for a variety of aneurysms. Visceral and isolated iliac aneurysms are relatively uncommon, but with the exception of common iliac aneurysms they can be very challenging to treat by open surgical methods. Although their incidence makes it highly unlikely that firm evidence will ever be available from randomised studies, it is clear that a variety of endovascular therapies are now available which provide successful treatment, at least in the medium term, whilst avoiding the potential complications of difficult surgery. The use of ultrasound compression and more recently percutaneous thrombin injection has been a revolution in the management of femoral, and other, false aneurysms occurring after catheterisation, so that few of these patients now need to be managed with open surgery.