Michel M. P. J. Reijnen

Multicenter Nellix EndoVascular Aneurysm Sealing system experience in aneurysm sac sealing

OBJECTIVE Despite improvements in endograft devices, operator technique, and patient selection, endovascular repair has not achieved the long-term durability of open surgical aneurysm repair. Persistent or recurrent aneurysm sac flow from failed proximal sealing, component failure, or branch vessel flow underpins a significant rate of reintervention after endovascular repair. The Nellix device (Endologix, Irvine, Calif) employs a unique design with deployment of polymer-filled EndoBags surrounding the endograft flow lumens, sealing the aneurysm sac space and potentially reducing complications from persistent sac flow. This retrospective analysis represents the initial experience in consecutive patients treated with the device in real-world practice. METHODS This study was performed at six clinical centers in Europe and one in New Zealand during the initial period after commercialization of the Nellix device. Patients underwent evaluation with computed tomography and other imaging modalities following local standards of care. Patients were selected for treatment with Nellix and treated by each institution according to its endovascular repair protocol. Clinical and imaging end points included technical success (successful device deployment and absence of any endoleak at completion angiography), freedom from all-cause and aneurysm-related mortality, endoleak by type, limb occlusion, aneurysm rupture, and reintervention. RESULTS During a 17-month period, 171 patients with abdominal aortic aneurysms were treated with the Nellix device and observed for a median of 5 months (range, 0-14 months). The 153 male and 18 female patients with mean age of 74 ± 7 years had aneurysms 61 ± 9 mm in diameter with an average infrarenal neck length of 28 ± 15 mm and infrarenal angulation of 37 ± 22 degrees. Technical success was achieved in all but two patients (99%); one patient had a type Ib endoleak and another had a type II endoleak. Through the last available follow-up, type Ia endoleak was observed in five patients (3%), type Ib endoleak in four patients (2%), and type II endoleak in four patients (2%). There were eight limb occlusions (5%), among which seven were evident at the 1-month follow-up visit. Aneurysm-related reinterventions were performed in 15 patients (9%). There were no aneurysm ruptures or open surgical conversions. CONCLUSIONS This first multicenter postmarket report of the Nellix device for infrarenal abdominal aortic aneurysm repair demonstrates satisfactory results during the initial learning phase of this new technology. The rate of aneurysm exclusion was high, and frequency of complications was low. More definitive conclusions on the value of this novel device await the results of the ongoing Nellix EVAS FORWARD Global Registry and the EVAS FORWARD investigational device exemption trial.

The relevance of aortic endograft prosthetic infection

BACKGROUND Vascular prosthetic graft infection is a severe complication after open aortic aneurysm repair. Reports of infected endografts are scarce. General treatment consensus with infected graft material is that it should be removed completely. The objective of this study was to describe the incidence of endograft infection after endovascular repair of abdominal (EVAR) and thoracic aortic aneurysm (TEVAR) and to report treatment options and their outcome. METHODS A retrospective cohort study was performed of patients endovascularly operated for abdominal and thoracic aortic aneurysm in two large hospitals (one tertiary referral center and one large community hospital) between March 1996 and June 2009. Diagnosis of infected endograft was made based on clinical findings, blood tests and cultures, imaging studies (computed tomography, fludeoxyglucose positron emission tomography), and intraoperative findings at reoperation. RESULTS Eleven patients with an infected endograft were identified in 1431 endovascular procedures. One other patient was referred from another hospital. Patients were aged 68 ± 9 years, and all but one were male. The median time from initial TEVAR/EVAR to the diagnosis of infection was 115 days (range, 7-3748 days), with 42% of patients presenting within 3 months after TEVAR/EVAR. Seven patients were diagnosed with endograft infection after elective TEVAR/EVAR and five after emergency TEVAR/EVAR. The incidence was significantly higher in patients that were treated in an emergency setting (0.56% vs 2.79%; P = .002), while there was no significant difference between TEVAR and EVAR procedures (1.37% vs 0.77%). All patients were initially treated with antibiotic therapy, which was complemented with surgical intervention in six patients. In four patients, the infected graft material was completely explanted. Isolated microorganisms included Staphylococcus species (n = 4), Streptococcus species (n = 4), Enterobacter cloacae (n = 1), Escherichia coli (n = 1), Pseudomonas aeruginosa (n = 1), and Listeria monocytogenes (n = 1). Median time of follow-up was 201 days (range, 6-2023 days). During the study period, three out of 12 patients died, of which two were treated conservatively (P = ns). At their last follow-up visit, seven of nine patients still used antimicrobial therapy. CONCLUSIONS The incidence of endograft infection is below 1%, with a mortality rate of 25%. Although consensus is that infected graft material should always be removed, this study shows no significant difference in mortality between the conservatively- and the surgically-managed group, possibly related to the small sample size. There may be a role for conservative treatment in selected cases of patients with an infected endograft.

The Persistent Sciatic Artery

BACKGROUND A persistent sciatic artery (PSA) is a rare vascular anomaly with an estimated incidence of 0.03-0.06%. During early embryonic development, the sciatic artery usually disappears when the superficial femoral artery has developed properly. This study aimed to assess the clinical presentation and outcome of a PSA. METHOD A systematic review of all cases of PSA published between 1964 and 2007 was performed. RESULTS In this review, 159 PSAs were described in 122 patients. The mean age at which the PSA was discovered was 57 years, and the incidence was equally distributed with regards to gender. The majority of PSAs was unilateral (70%) and of the complete type (79%). Ninety-one patients (80%) presented with symptoms including intermittent claudication, ischaemia, a pulsating mass or neurological symptoms. An aneurysm was found in 48%, a stenosis in 7%, an occlusion of the PSA in 9% and an occlusion of an artery distal to the PSA in 6% of the subjects. The treatment depended on the symptoms and classification of the PSA. In nine cases (8%), an amputation was required eventually. CONCLUSION The PSA is a rare anomaly with a high incidence of complications including aneurysm formation and ischaemia that may lead to amputation. Strategies for follow-up could not be deduced from the available literature.

Endovascular Aneurysm Sealing for Juxtarenal Aneurysm Using the Nellix Device and Chimney Covered Stents

Purpose: To show the feasibility of the Nellix device in conjunction with a chimney technique for treating juxtarenal aneurysms in two patients who were deemed unsuitable for fenestrated endovascular aneurysm repair or open surgery. Case Reports: Two men aged 83 and 81 years were referred with a juxtarenal abdominal aortic aneurysm (66 and 69 mm, respectively). Both were considered for open surgery as well as custom-made fenestrated stent-graft but deemed unsuitable for both options. They were both treated using the Nellix endoprosthesis in combination with chimney grafts to preserve the renal arteries. Technical success was achieved in both cases, with successful aneurysm exclusion and target vessel preservation (the right renal artery in the first case and both renal arteries in the second). At 6 months, duplex ultrasound and computed tomographic angiography of the first patient showed no signs of endoleak and patent renal arteries. The second patient developed a right retroperitoneal hematoma with minor extravasation near the lower pole of the right kidney for which coil embolization was necessary. The subsequent clinical sequelae led to respiratory insufficiency and ultimately death. Conclusion: The use of the Nellix endoprosthesis combined with chimney grafts is technically feasible. The addition of chimney grafts can increase the applicability of endovascular aneurysm sealing to treat short-neck and juxtarenal aneurysms. Further studies are needed to confirm these findings and establish longer term outcome.

Outcome-based anatomic criteria for defining the hostile aortic neck

OBJECTIVE There is abundant evidence linking hostile proximal aortic neck anatomy to poor outcome after endovascular aortic aneurysm repair (EVAR), yet the definition of hostile anatomy varies from study to study. This current analysis was undertaken to identify anatomic criteria that are most predictive of success or failure at the aortic neck after EVAR. METHODS The study group comprised 221 patients in the Aneurysm Treatment using the Heli-FX Aortic Securement System Global Registry (ANCHOR) clinical trial, a population enriched with patients with challenging aortic neck anatomy and failure of sealing. Imaging protocols were not protocol specified but were performed according to the institutions standard of care. Core laboratory analysis assessed the three-dimensional centerline-reformatted computed tomography scans. Failure at the aortic neck was defined by type Ia endoleak occurring at the time of the initial endograft implantation or during follow-up. Receiver operating characteristic curve analysis was used to assess the value of each anatomic measure in the classification of aortic neck success and failure and to identify optimal thresholds of discrimination. Binary logistic regression was performed after excluding highly intercorrelated variables, creating a final model with significant predictors of outcome after EVAR. RESULTS Among the 221 patients, 121 (54.8%) remained free of type Ia endoleak and 100 (45.2%) did not. Type Ia endoleaks presented immediately after endograft deployment in 58 (58.0%) or during follow-up in 42 (42.0%). Receiver operating characteristic curve analysis identified 12 variables where the classification of patients with type Ia endoleak was significantly more accurate than chance alone. Increased aortic neck diameter at the lowest renal artery (P = .013) and at 5 mm (P = .008), 10 mm (P = .008), and 15 mm (P = .010) distally; aneurysm sac diameter (P = .001), common iliac artery diameters (right, P = .012; left, P = .032), and a conical (P = .049) neck configuration were predictive of endoleak. By contrast, increased aortic neck length (P = .050), a funnel-shaped aortic neck (P = .036), and neck mural thrombus content, as measured by average thickness (P = .044) or degrees of circumferential coverage (P = .029), were protective against endoleak. Binary logistic regression identified three variables independently predictive of type Ia endoleak. Neck diameter at the lowest renal artery (P = .002, cutpoint 26 mm) and neck length (P = .017, cutpoint 17 mm) were associated with endoleak, whereas some mural neck thrombus content was protective (P = .001, cutpoint 11° of circumferential coverage). CONCLUSIONS A limited number of independent anatomic variables are predictive of type Ia endoleak after EVAR, including aortic neck diameter and aortic neck length, whereas mural thrombus in the neck is protective. This study suggests that anatomic measures with identifiable threshold cutpoints should be considered when defining the hostile aortic neck and assessing the risk of complications after EVAR.

Changing Profiles of Diagnostic and Treatment Options in Subclavian Artery Aneurysms

BACKGROUND Subclavian artery aneurysms (SAAs) are rare and may cause life- and limb-threatening complications. Therapeutic options greatly differ as do access alternatives. The aim of the study was to assess its clinical presentation, diagnostics and therapeutic options as reported in the literature. METHOD A literature search was performed of the Medline, Cochrane and EMBASE databases. All articles, published until September 2009, describing treatment of an SAA were included. RESULTS A total of 191 reports, of which 126 met the inclusion criteria, were identified and were published from June 1915 until September 2009. Of these, 394 SAAs were described in 381 patients, with a mean age of 52+/-16 years. The median diameter was 40 mm (range: 10-180 mm). The aetiology appeared to change in time towards more exogenous causes. Fifty-one percent of the SAAs presented with a pulsating mass, shoulder pain and/or non-specific chest pain. Embolisation, rupture and thrombosis were present in 16%, 9% and 6% of patients, respectively, and their incidence was related to the anatomical localisation of the SAA. Open surgery and endovascular repair had a complication rate of 26% and 28%, respectively (p=0.49). Cardiopulmonary complications were restricted to open repair. Mortality rates for open and endovascular techniques were similar (5%). The mortality rates for conventional elective and emergency procedures were 3% and 13%, respectively, and for endovascular repair 4% and 8%, respectively. CONCLUSION The profiles of diagnostic and treatment options of SAAs are changing. Although guidelines considering timing of intervention may not be conducted from available literature, intervention appears to be indicated, especially in distal SAAs, due to the risk of thrombo-embolic complications. Endovascular repair and hybrid procedures appear to be the preferred treatment modalities, due to a lower rate of cardiopulmonary complications.

Results of the Nellix system investigational device exemption pivotal trial for endovascular aneurysm sealing

OBJECTIVE The Nellix EndoVascular Aneurysm Sealing system (Endologix, Inc, Irvine, Calif) is a novel approach to abdominal aortic aneurysm (AAA) endovascular repair whereby biocompatible polymer is employed to exclude and to seal the AAA sac. We report 30-day results of the U.S. pivotal trial. METHODS Consecutive, eligible, consenting patients were enrolled at 29 sites in the United States and Europe. Inclusion criteria required an asymptomatic infrarenal AAA, with aortic neck length ≥10 mm and angle to the sac ≤60 degrees, aortic neck diameter of 18 to 32 mm, aneurysm blood lumen diameter ≤6 cm, common iliac artery lumen diameter of 9 to 35 mm, access artery diameter ≥6 mm, and serum creatinine level ≤2 mg/dL. Follow-up at 30 days included clinical assessment and computed tomography angiography evaluation of endoleaks and device integrity as assessed by a core laboratory. The primary safety end point is the incidence of independently adjudicated 30-day major adverse events (MAEs), with success defined as superiority with reference to the Society for Vascular Surgery open repair control group (56%). RESULTS Between January and November 2014, 150 trial patients having a mean AAA diameter of 5.8 cm were enrolled and treated with the Nellix system with 100% procedural success. One early death (0.7%) occurred secondary to multisystem organ failure. All 149 surviving patients completed 30-day follow-up. There were no aneurysm ruptures, conversions, limb thromboses, stent fractures, or stent kinking. Five early MAEs occurred in four patients (2.7%) and included one death, bowel ischemia (1), renal failure (2), and respiratory failure (1). One (0.7%) secondary intervention to treat inadvertent coverage of a renal artery was performed. The core laboratory identified nine (6%) endoleaks (one type I, eight type II) on 30-day computed tomography angiography. Freedom from MAE was 97.3% (95% confidence interval, 93.3%-99.0%). CONCLUSIONS In selected patients, perioperative outcomes with the Nellix system for endovascular aneurysm sealing are encouraging, with very low 30-day morbidity and mortality and high procedural success. The primary safety end point has been achieved. Longer term follow-up is in progress.

Endovascular Aneurysm Sealing Early and Midterm Results From the EVAS FORWARD Global Registry

Purpose: To report the early and 12-month results of a global registry of patients treated with endovascular aneurysm sealing (EVAS) for abdominal aortic aneurysms (AAAs). Methods: The EVAS FORWARD Global Registry was a postmarket, multicenter, open-label, single-arm registry that enrolled 277 patients (mean age 75 years; 228 men) treated with the Nellix EVAS system for nonruptured AAAs at 18 sites over a 1-year period. The cohort had challenging aortic anatomy, with 17% having a proximal aortic neck length <10 mm, 8% a neck angulation >60°, and 20% an iliac diameter >25 mm. Baseline and follow-up computed tomography images were assessed by an independent core laboratory, and major adverse events were reviewed by an independent safety committee. Results: Three patients died within 30 days of the procedure (none device-related). There were 13 endoleaks recorded in this time frame: 8 type Ia, 1 type Ib, and 5 type II. Root cause analysis demonstrated that the majority of type Ia endoleaks were due to technical error (low device placement and underfilling of the endobags). Between 30 days and 1 year, there were 4 new type Ia endoleaks; all were treated. There was also 1 type III endoleak between a Nellix device and a distal extension limb. At 1 year, the persistent endoleak rate was 0.7% (1 type Ia and 1 type II). The Kaplan-Meier estimates of freedom from types I and II endoleak at 12-month follow-up were 96% and 98%, respectively. The estimate of freedom from open conversion (n=7) was 98% at 12 months and the rate of freedom from any reintervention was 92%. The need for secondary intervention was associated with aortic morphology; for patients meeting the requirements of the instructions for use (IFU), the freedom from reintervention at 12 months was 98% compared with 86% when the implant was outside the IFU (p=0.009). At 1 year, the estimates of freedom from aortic-related and all-cause mortality were 98% and 95%, respectively. Conclusion: The EVAS FORWARD Global Registry documents the 12-month outcome of EVAS in an unselected group of patients with challenging aortic morphology. The results at present appear acceptable with regard to perioperative outcomes and complications. The type II endoleak rate is low. The place of EVAS in the armamentarium of techniques to treat AAAs will be defined by durability data in the longer term.

The Ongoing Battle Between Infrapopliteal Angioplasty and Bypass Surgery for Critical Limb Ischemia

BACKGROUND Critical limb ischemia (CLI) represents the extreme of the peripheral arterial occlusive disease spectrum and is associated with high mortality. Limb salvage often requires infrapopliteal revascularization by either angioplasty or bypass surgery. The past decade has witnessed a paradigm shift in CLI management toward endovascular treatment. This narrative review describes the clinical outcome, treatment strategy, and limitations of both modalities. METHOD A literature search was performed of the PubMed and Cochrane databases. All articles, published until September 2011, describing treatment by infrapopliteal arterial revascularization were included. RESULTS Angioplasty and bypass surgery are both related to a limb salvage rate of approximately 80% at 3-year follow-up. Patency rates appear to be higher after surgery. A reliable comparison of the two modalities, however, is complicated by various confounders, including patient selection, lesion characteristics, and complication rates. Additionally, most studies did not describe the standard use of best medical treatment or outcome for relief of ischemic pain, wound healing, or functional improvement. CONCLUSION Infrapopliteal angioplasty and bypass surgery both provide an acceptable limb salvage rate, but patency appears to be better after bypass surgery. Both modalities are likely to be complementary. Additional randomized trials are indicated to provide a treatment algorithm for patients with CLI and infrapopliteal arterial occlusive disease.

Current Role of Imaging in Diagnosing Aortic Graft Infections

Vascular prosthetic graft infection is a rare but serious complication after aortic graft replacement, with high morbidity and mortality rates. Therefore, adequate diagnostics are needed to detect and treat these infections as early as possible. Several imaging modalities provide different diagnostic values for detecting prosthetic graft infection. Previous studies reported on the diagnostic value of ultrasound, computed tomography imaging, magnetic resonance imaging, fluorodeoxyglucose-positron emission tomography, and single-photon emission computed tomography. In addition, adjunctive studies on new and promising techniques to detect prosthetic graft infection (eg, bio-optical imaging and target imaging with nuclear techniques) have also been investigated. This review provides a summary of noninvasive imaging modalities and their diagnostic values in order to evaluate and treat possible vascular graft infections as early as possible.