Hepatorenal bypass allowing fenestrated endovascular repair of juxtarenal abdominal aortic aneurysm: a case report

A 61-year-old man presented with a 66-mm juxtarenal aortic aneurysm. He was unfit for open repair. The anatomical proximity of his right renal artery (RRA) and his superior mesenteric artery (SMA) precluded fabrication of an endograft allowing perfusion of both vessels. He underwent a hepato-renal bypass to his RRA and subsequent fenestrated endovascular aneurysm repair (EVAR) using an endoprosthesis with fenestrations for the SMA and the left renal artery (LRA), and a scallop for the coeliac trunk. Follow-up imaging showed all visceral vessels to be perfused. The use of this limited hybrid approach allows endovascular treatment of aneurysms that are initially unsuitable for such an approach.

Endovascular thoracoabdominal aortic aneurysm repair: a literature review of early and mid-term results

Successful endovascular repair of abdominal aortic aneurysms (AAA) requires undilated proximal (infrarenal neck) and distal landing zones (common or external iliac arteries). A range of approved endografts are available to exclude such aneurysms. Recent multicentric prospective randomized trials have demonstrated a short and midterm decrease in aneurysm-related deaths of the endovascular technique compared to open surgery. These results have induced an overall increase in the rate of endovascular repair of AAA. Patients with more complex aortic aneurysms, involving the visceral vessels (juxta, para and thoraco-abdominal aneurysms (TAAA), have increased perioperative morbidity and mortality after open repair compared to AAA. These patients could potentially benefit from an endovascular approach. Branched and fenestrated endografts have been developed to address this endovascular challenge. This review was carried out on the current literature evaluating these new endovascular complex procedures. Spinal cord ischemia, 30-day mortality and branch patency rates after endovascular exclusion of TAAA ranged from 2.7% to 20%, 0% to 9.1% and 96% to 100% respectively. Mid-term results of endovascular complex aortic repairs are favourable compared to open surgery in high risk patients. Long-term results will be necessary to evaluate specific complications such as migration, material fatigue and component separation that can result in loss of visceral branches.

Zenith abdominal aortic aneurysm endovascular graft: a literature review

The early experience of endovascular aneurysm repair (EVAR) using ''first generation'' devices was disappointing. There was an appreciable incidence of delayed, post-EVAR, aneurysm rupture. This was primarily a consequence of structural device failure. These failures provided important lessons for re-design and the modern ''second generation'' devices, including the Zenith (Cook Inc, Bloomington, IN, USA) endograft, are thought to be more reliable, particularly providing better fixation and sealing and also a more durable stent/fabric structure. This article comprises a review of the English literature detailing the endovascular treatment of abdominal aortic aneurysms using the Zenith endograft. It focuses on clinical studies or trials with intermediate to long-term follow-up, and related the literature to our own experience. In the series examined (N.=2 017 patients) the early mortality rate ranged from 0% to 4.1% and the technical success rate from 97.7% to 100%. The re-intervention rate was related to the length of follow-up (6.8% to 14%). Conversion rates were consistently <1%. There was a low incidence of device migration, limb thrombosis, component separation and stent fracture. These data support the ongoing use of the Zenith endovascular graft in patients with abdominal aortic aneurysms suitable for EVAR.

Biological behaviour of an endothelial cell line (HPMEC) on vascular prostheses grafted with hydroxypropylgamma-cyclodextrine (HPgamma-CD) and hydroxypropylbeta-cyclodextrine (HPbeta-CD)

The cytocompatibility of cyclodextrins (CDs) grafting on vascular polyester (PET) prostheses for further loading with biomolecules was investigated in this study. Viability tests demonstrated no toxicity of HP-CDs and PolyHP-CDs at 4,000 mg/l with survival rates of 80 to 96%. Proliferation tests using the human pulmonary microvascular endothelial cell line (HPMEC-ST1) revealed an excellent biocompatibility for Melinex (Film form of PET). For Polythese and Polymaille, a good proliferation rate was observed at 3 days (60-80%) but decreased at 6 days (56-73%). For all CD-grafted samples, low proliferation rates were observed after 6 days (35-38%). Vitality tests revealed excellent functional capacities of HPMEC cells after 3 and 6 days for all samples. Adhesion kinetics tests showed a similar adhesion of HPMEC cells on control and Melinex. A low adhesion was observed on Polythese and especially on Polymaille compared to control. After CD grafting, the cell adhesion was decreased. The woven or knitted architecture and CD grafting were the most likely causes of this weak adhesion. The adhesion kinetic test was confirmed by SEM observations and immunocytochemistry. The low proliferation of HPMEC on virgin prostheses and especially on grafted prostheses was not due to a cytotoxic effect, but to the physical surface characteristics of the prostheses.

Surgical treatment of renal cell carcinoma with right atrial thrombus: Early experience and description of a simplified technique

Operative management of patients presenting renal cell carcinoma's (RCC) with right atrial tumor thrombus extension is a technical challenge. It requires the use of cardiopulmonary bypass (CPB). The aim of this study was to report our early experience and to describe a simplified CPB technique. 5 consecutive patients underwent surgical resection by a joint cardiovascular and urological team. The ascending aorta was canulated. The venous drainage was achieved using a proximal canula inserted in the superior vena cava and a distal canula inserted in the IVC below the renal veins. Right atrium thrombus extension was extracted under normothermic CPB without cross clamping or cardioplegic arrest. A cavotomy was performed at the ostium of the renal vein and an endoluminal occlusion catheter was introduced. The thrombectomy and the radical nephrectomy were then performed. The occurrence of gaseous or tumor embolism, operative time, perioperative bleeding, and post-operative complications were assessed. Mean patients age was 62.9 years. Atrial and caval thrombectomy were achieved successfully in all patients. Mean operative time was 206 min. Mean CPB time was 62 min. Mean hospital stay was 18.8 days. One death occurred, due to respiratory failure. An asymptomatic early thrombosis of the IVC was diagnosed by CT scan in 1 patient. The four remaining patients were alive 6 months after the surgical procedure. Minimally invasive CPB technique can be used to treat intra atrial thrombus tumor extension arising from renal cell carcinoma. It can be performed safely with acceptable complications rate.

Branched Grafting for Aortoiliac Aneurysms

PURPOSE

To evaluate a novel approach to preserve pelvic perfusion during endovascular AAA repair in patients with common iliac aneurysms extending to the iliac bifurcation.

MATERIALS AND METHODS

A multicenter prospective analysis of patients undergoing implantation of a branched endograft designed to perfuse the internal iliac artery was conducted. All patients enrolled were considered high risk for open surgical repair and presented with common iliac artery aneurysms greater than 20mm and anatomy amenable to implant the branched device. Preoperative high resolution spiral CT, and follow-up CT studies in addition to abdominal radiographs were obtained at discharge, 1, 6, 12, and 24 months.

RESULTS

Between 2003 and 2006, 52 patients (53 internal iliacs) were implanted with an investigational device. Mean common iliac aneurysm maximal diameter was 38 mm. The branch graft was combined with a proximal standard bifurcated component (61%), a fenestrated or a visceral branch component (33%), an aortouni-iliac component (2%), and alone in 2 patients (4%, following prior aortobi-iliac repair). Technical success was achieved in 94% of patients. Within the first month, 6 (11%) internal iliac branches occluded. No occlusions were noted after 1 month. The mean follow-up was 14.2 months. Common iliac aneurysm shrinkage was noted in 42% and 81% of patients at 6 and 12 months. There were no rupture, aneurysm related deaths or conversions, but there were 7 deaths during follow-up.

CONCLUSIONS

The placement of endovascular prostheses that maintain antegrade perfusion of one or both internal iliac arteries is feasible, and early results provide evidence for optimism with regard to safety and efficacy.

Vascular prostheses with controlled release of antibiotics

Vascular prostheses were functionalised with the aim to obtain a slow release of antibiotics in order to reduce postoperative infections. The original process that we present in this paper is based on the use of a family of cage molecules named cyclodextrins (CD). These compounds have the ability to form reversible inclusion complexes with drugs such as antibiotics. The aim of this work was to graft CD onto the prosthesis, so that an antibiotic can be bound on it by this inclusion phenomenon, and then be progressively released over a prolonged period by a complex dissociation mechanism. This paper presents the first part of this research program and concerns mainly the study of the functionalization parameters. It presents surface characterization results of the modified prostheses. The PET prostheses were immersed into a solution containing a cross linking agent, cyclodextrins (beta-CD, gamma-CD, HP-beta-CD and HP-gamma-CD) and a catalyst and were padded. Grafting occurred by the mean of a thermofixation step at a temperature comprised between 140 and 180 degrees C. It was observed that the support was permanently modified when the CD polymer that coated the fibres resisted to the final washing process. Grafting rates of 12 wt% in CD polymer could be reached. It was also observed that the fibre coating reaction induced an increase of the permeability of the grafts.

Vascular prostheses with controlled release of antibiotics

Viability tests by the colony forming method show no toxicity for all CDs (beta-CD, gamma-CD, HPbeta-CD and HPgamma-CD) and their associated polymer. A survival rate of 100% is observed for all CDs at high concentration 400 ppm. Proliferation tests revealed a low proliferation of L132 cells on grafted vascular prostheses and untreated prostheses and good proliferation on Melinex (film form of PET). A proliferation of 17% is observed after 3 days of incubation and decrease at 4% after 6 days on prostheses. Melinex exhibits a proliferation rate as the controls. Vitality tests confirm proliferation tests and show a good vitality of cells even for low cell amounts. From these experiments it becomes obvious that the decreasing proliferation rate is not a cytotoxic effect but is due to the chemical and/or physical surface characteristics. A similar result is obtained for cell adhesion kinetics between grafted vascular prostheses and control. After 2 h adhesion, a lower adhesion is observed on untreated prostheses. Theses results were confirmed by immunochemistry and morphology tests. This cell adhesion inhibiting effect of the PET prostheses contributes to a better "survival" of vascular prostheses without secondary obstruction or stenosis.

[The best of vascular medicine in 2005]

It is illusory to think that one year is long enough to establish all the truths that will guide our clinical practice in vascular medicine. On the contrary, one year was long enough to contradict what the preceding twelve months had set out to demonstrate. Consequently, promising trials in the treatment of abdominal aortic aneurysms by endoprostheses have been the object of contradictory debate with regards to the long-term benefits. In fundamental research, circulating progenitors of endothelial cells have been shown to be a marker of atherosclerosis, but is it a better marker than LDL-cholesterol values? The demonstration that these progenitors are of value in the treatment of essential ischaemia of the lower limbs is awaited. Finally, ximelagatran, a direct thrombin antagonist, seemed to have all the qualities of an ideal anticoagulant: easy to use, safe... until the report of raised hepatic enzymes, the clinical relevance of which remains to be determined. In the good news section: the Systolic Pressure Index, an unquestioned marker of arterial disease. Its reduction was known to be correlated with the prevalence of cardiovascular complications. However, it has now been shown that an increase in the index is also associated with cardiovascular complications, a real U-shaped curve. Renal arterial stenosis should be considered in patients with left ventricular failure presenting with flash pulmonary oedema. In the absence of cardiac pathology, BNP would seem to be a good biological marker of haemodynamically significant renal arterial stenosis. Finally, should superficial femoral artery stenosis be treated by an active stent. To date, there is no formal proof.

Vascular PET Prostheses Surface Modification with Cyclodextrin Coating: Development of a New Drug Delivery System

PURPOSE

Cyclodextrins (CDs) are torus shaped cyclic oligosaccharides with a hydrophobic internal cavity and a hydrophilic external surface. We performed and analysed an antibiotic binding on Dacron (polyethyleneterephtalate, PET) vascular grafts, previously coated with CDs based polymers.

METHODS

The CDs coating process was based on the pad-dry-cure method patented in our laboratory. The Dacron prostheses were immersed into a solution containing a polycarboxylic acid, a cyclodextrin and a catalyst, and placed into a thermofixation oven before impregnation with an antibiotic solution (Vancomycin). Biocompatibility tests were performed with L132 human epithelial cells. The antibiotic release in an aqueous medium was assessed by batch type experiments using UV spectroscopy.

RESULTS

Viability tests confirmed that the CDs polymers coating the Dacron fibers were not toxic towards L132 cell. Cell proliferation was similar on coated and uncoated grafts. A linear release of Vancomycin was observed over 50 days.

CONCLUSION

Our results demonstrate the feasibility of coating CDs onto vascular Dacron grafts. Biological tests show no toxicity of the different cyclodextrins coated. A linear release of antibiotics was depicted over 50 days, demonstrating that cyclodextrin grafting was an efficient drug delivery system.

Primary Endovascular Repair of Juxtarenal Aneurysms with Fenestrated Endovascular Grafting

PURPOSE

To evaluate outcomes of an endovascular graft incorporating the visceral aortic segment with graft material in the setting of juxtarenal aneurysms.

MATERIALS AND METHODS

A prospective analysis of patients undergoing implantation of an endovascular device with graft material proximal to the renal arteries was conducted. All patients were deemed unacceptable candidates for open surgical repair and had proximal neck length=<10 mm, or =<15 mm with a compromising morphology (funnel or thrombus). Fenestrations were customized to accommodate aortic branch anatomy based upon CT and intravascular ultrasound data. Selective visceral ostia were treated with balloon expandable stents following endograft deployment. All patients were evaluated with CT, duplex ultrasound, and abdominal radiograph at discharge, 1, 6, 12 and 24 months.

RESULTS

A total of 32 patients were enrolled in the trial. Short proximal necks (3-10 mm) were present in 22, and 10 had necks 10-15 mm in length with concomitant angulation or thrombus compromising neck quality. Endograft design included bifurcated (30) and aortic tube (2) systems. A total of 83 visceral vessels were incorporated (mean of 2.6 per patient). These most commonly included both renal arteries and the SMA. All prostheses were implanted successfully without the acute loss of any visceral arteries. The mean follow-up was 9.2 months (range 0-24 months). One patient died within 30 days of device implantation and hypogastric bypass following the development of aspiration pneumonia. Three early (<30 days) and three late secondary interventions were performed. The 30-day endoleak rate was 6.5%. The aneurysm sac decreased greater than 5 mm in 58% of patients at 6 months and in 75% of patients at 12 months. One patient, with a persistent type II endoleak had 5 mm of sac growth over 12 months. Six patients had transient or permanent elevation of serum creatinine (>30% from baseline), with one requiring hemodialysis. Of the 83 vessels incorporated, three late stenoses (all successfully treated with an endovascular approach) and two renal occlusions were detected during follow-up. Three patients died of unrelated causes during the follow-up period.

CONCLUSIONS

The placement of endovascular prostheses with graft material incorporating the visceral arteries is technically feasible. The incidence of endoleaks is exceptionally low. It remains critical to follow the status of stented visceral vessels, and establish the long-term efficacy of this type of repair.

Angioplasty and stenting for high-grade internal carotid artery stenosis: safety study in 39 selected patients

BACKGROUND

Carotid angioplasty and stenting (CAS) is sometimes used as an alternative to surgery, despite the lack of evidence for its safety and efficacy.

METHOD

Over a 33-month period, 39 consecutive patients with a stenosis >/=70% underwent CAS (4 in a randomized trial and 35 because of contra-indications for surgery).

RESULTS

In 5 patients (13%; 95% CI: 3-23), a major complication occurred (3 disabling ischaemic strokes, 1 myocardial infarction, 1 acute interstitial nephropathy). In 7 patients (18%; 95% CI: 6-30), a minor complication occurred (5 transient ischaemic attacks, 1 transient confusional state, 1 non-disabling ischaemic stroke).

CONCLUSION

CAS cannot be considered as a routine procedure and should be restricted to high-risk patients unfit for surgery.

Aortic Dissections: New Perspectives and Treatment Paradigms

Aortic dissection is a complex manifestation of disease of the arterial wall. The severity and consequences of a dissection are related to the physical characteristics and anatomic location of the tear as well as the underlying patient physiology. Despite in vitro and in vivo modeling advances, our understanding of the pathophysiology has been limited to evaluations of the success and failure of various treatment modalities. The indications for intervention have historically included rupture, intractable pain or hypertension, distal ischemia and degeneration of the aortic wall causing aneurysm formation. The management decisions for patients with dissections are dependent upon the abnormal anatomy, the acuity of the patient presentation, and physiology. Despite the availability of open surgery as a therapeutic option, acute dissections with evidence of ischemia are now handled using an endovascular approach that is specifically directed at the cause of the ischemia. Endovascular treatments include the placement of a stentgraft into the proximal aorta, branch vessel stenting, uncovered stent placement in the abdominal aorta, and aortic fenestrations. Chronic dissections, in contrast, are still most frequently managed with open surgical techniques. However, a subset of patients that are not candidates for traditional surgical repair of the thoracoabdominal aorta may be managed with a combined open mesenteric revascularization with subsequent endovascular grafting of the thoracoabdominal aorta.

Risk factors of early and late complications in patients undergoing endovascular aneurysm repair

OBJECTIVES

to identify pre-operative factors that could predict complications following from transluminal repair of abdominal aortic aneurysms (AAA).

METHODS

during a 5-year period, 96 consecutive patients underwent elective endovascular treatment of a AAA. In all patients, helical CT and/or Magnetic Resonance Imaging (MRI), and plain abdominal roentgenogram were performed at 1, 3, 6, 12, 18, and 24 months and yearly thereafter. Angiography was performed systematically 1 year after the stent-graft implantation, or earlier if helical CT or MRI diagnosed an increase in the maximal transverse diameter or a high flow endoleak.

RESULTS

early (<30 days) morbidity (12%) was significantly increased by pre-operative renal insufficiency (p < 0.01). Early mortality (2%) correlated with ASA score (p = 0.01). Median follow-up was 27 months (range 3-66). Mortality (12%) during follow-up was correlated to the pre-operative coronary status (p = 0.01). A type I endoleak was diagnosed in 18 patients (19%). Common iliac artery diameter was correlated with the presence of type I endoleak (p < 0.001). A type II endoleak was diagnosed in 47 (49%) patients. The diagnostic of type II endoleak was significantly increased (p = 0.001) in patients with pre-operative patent IMA associated with more than four patent lumbar arteries. The anatomic characteristics of the aneurysm were correlated to the additional endovascular procedures during stentgraft implantation (p = 0.01), and to the implantation of a complementary iliac limb extension during follow-up (p = 0.01).

CONCLUSIONS

the risk factors determined by this statistical analysis could help surgeons to select more accurately patients suitable for endovascular treatment.

Percutaneous endovascular treatment for stenoses and occlusions of infrarenal aorta and aortoiliac bifurcation: midterm results

OBJECTIVE

evaluation and comparison of the endovascular treatment of isolated aortic and aortoiliac atherosclerotic lesions (stenoses and occlusions).

METHODS

a percutaneous endovascular procedure was performed in 52 patients (38 men and 14 women) with a mean age of 52 years (range, 25-85 years). The baseline angiogram showed 35 aortic lesions (31 stenoses, 4 occlusions) and 17 aortoiliac lesions (14 stenoses, 3 occlusions). Percutaneous techniques used in this series included variable combinations of transluminal angioplasty and stenting. All stents placements were performed over-the-wire using the transfemoral route (most often bilateral approach). Clinical examination and Duplex-scan were performed at discharge, 1 month, 6 months, 12 months, and then yearly.

RESULTS

technical success was 100% for aortic and aortoiliac lesions. Angiographic success rates were comparable for aortic (91%) and aortoiliac (94%) lesions. No death occurred during or early after the endovascular intervention. Duplex-scan confirmed 100% patency rate at discharge. There was no significant difference between the aortic (94%) and aortoiliac (96%) groups regarding immediate clinical improvement. Mean follow-up was 34+/-31 months (range, 0-130 months). The cumulative primary patency rate at 36 months was 85% in the aortic group and 86% in the aortoiliac group. Clinical success, defined as a symptom-free status at the end of follow-up, was also similar in both groups.

CONCLUSION

endovascular treatment of isolated aortic lesions of the infra-renal aorta has favorable outcomes comparable to those of aortoiliac lesions.