Suprarenal Stent Research Articles

Early experience with patient-specific unibody bifurcated fenestrated-branched devices for complex endovascular aortic aneurysm repair

ObjectiveShort distances between the lowest visceral/renal artery and the aortic bifurcation are technically challenging during complex endovascular aortic aneurysm repair (EVAR), particularly after previous infrarenal repair. Traditionally, inverted limb bifurcated devices have been used in addition to fenestrated-branched (FB) endografts, but short overlap, difficult cannulation, and potential crushing of bridging stents are limitations for their use. This study reviews the early experience of patient-specific company manufactured devices (PS-CMDs) with a unibody bifurcated FB design for complex EVAR. MethodsConsecutive complex EVAR procedures over a 34-month period with unibody bifurcated FB-devices as part of physician-sponsored investigational device exemption studies at two institutions were reviewed. Unibody bifurcated FB designs included FB bifurcated or fenestrated inverted limb devices. End points included technical success, survival, frequency of type I or III endoleaks, limb occlusion, and secondary interventions. ResultsAmong 168 patients undergoing complex EVAR, 33 patients (19.6%; 78.7% male; mean age, 77 years) received unibody bifurcated FB PS-CMDs. FB bifurcated and fenestrated inverted limb devices were used in 31 (93.9%) and 2 (6.06%) patients, respectively. The median maximum aneurysm diameter was 61 mm (interquartile range [IQR], 55-69 mm). Prior EVAR was reported by 29 patients (87.9%), of whom 2 (6.06%) had suprarenal stents. A short distance between the lowest renal artery and aortic bifurcation was demonstrated in 30 patients (90.9%), with median distance of 47 mm (IQR, 38-54 mm). Preloaded devices were used in 23 patients (69.7%). A total of 128 fenestrations were planned; 22 (17.2%) were preloaded with guidewires and 5 (3.9%) with catheters. The median operative time was 238 minutes (226-300 minutes), with a median fluoroscopy time of 65.5 minutes (IQR, 56.0-77.7 minutes) and a median dose area product of 147 mGy∗cm2 (IQR, 105-194 mGy∗cm2). Exclusive femoral access was used in 14 procedures (42.4%). Technical success was 100%. Target vessel primary patency was 100% at a median follow-up time of 11.7 months (IQR, 3.5-18.6 months). Two patients (6.06%) required reintervention for iliac occlusion; one patient required stenting and the other a femoral-femoral bypass. No aortic-related deaths occurred after the procedure. During follow-up, 11 type II endoleaks (33.3%) and 1 type Ib endoleak (3.03%) were detected; the latter was treated with leg extension. No type Ia or III endoleaks occurred. ConclusionsComplex EVAR using unibody bifurcated FB-PS-CMDs is a simple, safe, and cost-effective alternative for the treatment of patients with short distances between the renal arteries and the aortic bifurcation. Further studies are required to assess benefits and durability of unibody bifurcated FB devices.

Early Clinical Outcomes of Initial Launch of the Zenith Alpha Abdominal Endovascular Graft in Japan

Purpose: This study retrospectively evaluated the 12-month outcomes of the Zenith Alpha Abdominal Endovascular graft (Zenith Alpha AAA, Cook, Inc, Bloomington, Indiana), which was launched partially in Japan in March 2019, starting with 9 selected sites. Methods: A retrospective analysis was performed of all endovascular aneurysm repairs (EVAR) for abdominal aortic aneurysms using the Zenith Alpha AAA. Late complications were defined as any aneurysm-related events occurring >30 days after EVAR, including an aneurysm sac enlargement of >5 mm and any reinterventions performed. Endoleaks without sac enlargement or reinterventions were excluded from late complications. Results: During the study period, 79 EVARs using the Zenith Alpha AAA were performed. The mean age was 76.6±6.9 years old, 91.1% of patients were male, and the mean aneurysm diameter was 51.1±7.5 mm. Instructions for use violation was observed in 27 patients (34.2%), most frequently being a severely angulated proximal neck (>60°). There were 4 intraoperative complications, including 2 unintentional partial renal artery coverages caused by the premature anchoring of the exposed suprarenal stent barb to the aortic wall, which was a result of the design change of the top cap deletion. Since it was a partial coverage without flow impairment and since renal stenting was unsuccessful, it was left untreated and had no subsequent renal function impairment. During the mean follow-up of 444±123 days, 74 patients completed 12 months of follow-up. Freedom from late complications at 12 months was 90.8%, which included 2 limb occlusions (2.5%). Of 71 patients with a 12-month computed tomography scan, there was only 1 type 1a endoleak (1.3%), 1 sac enlargement of >5 mm (1.3%), and an aneurysm sac shrinkage of >5 mm was observed in 42.2% of patients. There was no type 3 endoleak during the follow-up. Conclusions: This study demonstrated that the new generation of low-profile Zenith Alpha AAA has satisfactory early clinical outcomes, comparable to those obtained with the conventional Zenith endovascular graft. Long-term follow-up is needed to determine whether these favorable outcomes persist.

An unusual cause of failure in Zenith Alpha Abdominal endograft

BackgroundGraft disruption is an unusual complication of the endovascular abdominal aortic aneurysm repair (EVAR).Case presentationA 71-year-old man underwent standard EVAR with Zenith Alpha Abdominal endograft. Follow-up examinations revealed an initial significant sac shrinkage. At 24 months, duplex ultrasound (DUS) scan and computed tomography showed increase of the sac diameter associated with complete disconnection of the suprarenal stent-graft from the main body without evidence of endoleak. A standard relining with a thoracic endograft was performed between the suprarenal stent and the main body of the previous graft. At 6 months DUS revealed sac shrinkage.ConclusionsThis report demonstrates an uncommon cause of endograft failure with suprarenal stent disconnection from main body and highlights the need for continuous follow-up in patients undergoing EVAR.

Risk Factors, Dynamics, and Clinical Consequences of Aortic Neck Dilatation after Standard Endovascular Aneurysm Repair

Aortic neck dilatation (AND) occurs after endovascular aneurysm repair (EVAR) with self expanding stent grafts (SESs). Whether it continues, ultimately exceeding the endograft diameter leading to abdominal aortic aneurysm (AAA) rupture, remains uncertain. Dynamics, risk factors, and clinical relevance of AND were investigated after EVAR with standard SESs. All intact EVAR patients treated from 2000 to 2015 at a tertiary institution were included. Demographic, anatomical, and device related characteristics were investigated as risk factors for AND. Outer to outer diameters were measured at a single standardised aortic level on reconstructed computed tomography (CT) images. A total of 460 patients were included (median follow up 5.2 years, interquartile range [IQR] 3.0, 7.7 years; CT imaging follow up 3.3 years, IQR 1.3, 5.4). Baseline neck diameter was 24 mm (IQR 22, 26) and increased 11.1% (IQR 1.5%, 21.9%) at last CT imaging. Endograft oversizing was 20.0% (IQR 13.6, 28.0). AND was greater during the first year (5.2% [IQR 0, 11.7]) decreasing subsequently (two to four years to 1.4%/year [IQR 0.0, 4.5%], p ≤ .001) and was associated with suprarenal fixation endografts (t value = 7.9, p < .001) and oversizing (t value = 4.4, p < .001). AND exceeding the endograft was 3.5% (95% CI 2.2% – 4.8%) and 14.4% (95% CI 11.0% – 17.8%) at five and eight years, respectively. Excessive AND was associated with baseline neck diameter (OR 1.2/mm, 95% CI 1.05 – 1.41) while the Excluder endograft had a protective effect (OR 0.15, 95% CI 0.04 – 0.58). Excessive AND was associated with type 1A endoleak (HR 3.3, 95% CI 1.1 – 9.7) and endograft migration > 5 mm (HR 3.1, 95% CI 1.4 – 6.9). AND after EVAR with SES is associated with endograft oversizing and radial force but decelerates after the first post-operative year. Baseline aortic neck diameter and suprarenal stent bearing endografts were associated with an increased risk of AND beyond nominal stent graft diameter. However, it remains unclear whether patient selection, differences in endograft radial force or the suprarenal stent are accountable for this difference.

Risk Factors, Dynamics, and Clinical Consequences of Aortic Neck Dilatation after Standard Endovascular Aneurysm Repair

Aortic neck dilatation (AND) occurs after endovascular aneurysm repair (EVAR) with self expanding stent grafts (SESs). Whether it continues, ultimately exceeding the endograft diameter leading to abdominal aortic aneurysm (AAA) rupture, remains uncertain. Dynamics, risk factors, and clinical relevance of AND were investigated after EVAR with standard SESs. All intact EVAR patients treated from 2000 to 2015 at a tertiary institution were included. Demographic, anatomical, and device related characteristics were investigated as risk factors for AND. Outer to outer diameters were measured at a single standardised aortic level on reconstructed computed tomography (CT) images. A total of 460 patients were included (median follow up 5.2 years, interquartile range [IQR] 3.0, 7.7 years; CT imaging follow up 3.3 years, IQR 1.3, 5.4). Baseline neck diameter was 24 mm (IQR 22, 26) and increased 11.1% (IQR 1.5%, 21.9%) at last CT imaging. Endograft oversizing was 20.0% (IQR 13.6, 28.0). AND was greater during the first year (5.2% [IQR 0, 11.7]) decreasing subsequently (two to four years to 1.4%/year [IQR 0.0, 4.5%], p ≤ .001) and was associated with suprarenal fixation endografts (t value= 7.9, p < .001) and oversizing (t value= 4.4, p < .001). AND exceeding the endograft was 3.5% (95% CI 2.2% - 4.8%) and 14.4% (95% CI 11.0% - 17.8%) at five and eight years, respectively. Excessive AND was associated with baseline neck diameter (OR 1.2/mm, 95% CI 1.05 - 1.41) while the Excluder endograft had a protective effect (OR 0.15, 95% CI 0.04 - 0.58). Excessive AND was associated with type 1A endoleak (HR 3.3, 95% CI 1.1 - 9.7) and endograft migration > 5 mm (HR 3.1, 95% CI 1.4 - 6.9). AND after EVAR with SES is associated with endograft oversizing and radial force but decelerates after the first post-operative year. Baseline aortic neck diameter and suprarenal stent bearing endografts were associated with an increased risk of AND beyond nominal stent graft diameter. However, it remains unclear whether patient selection, differences in endograft radial force or the suprarenal stent are accountable for this difference.

The lift snorkel technique for type Ia endoleak after fenestrated endovascular aneurysm repair of a juxtarenal abdominal aortic aneurysm

BackgroundThe snorkel technique for a juxtarenal abdominal aortic aneurysm (JAAA) is an important treatment option for high-risk patients. We report the lift snorkel technique through the trans-femoral access for a type Ia endoleak after fenestrated endovascular aneurysm repair (FEVAR) in a case of difficult trans-brachial access.Case presentationA 76-year-old woman who had JAAA presented with a type Ia endoleak and sac expansion after FEVAR. We planned for proximal additional stentgraft with the bilateral renal artery snorkel technique. However, during the secondary intervention, it was difficult to cannulate to the left renal artery through the trans-brachial access due to interference of the supra-renal stent. Stentgraft was eventually delivered into the left renal artery via the trans-femoral access with a 5 Fr sheath. A plain angioplasty balloon was inserted coaxially through the sheath. The balloon was inflated in the proximal end of the stentgraft and then pushed up to replace the proximal end from down to up. The additional aortic cuff was deployed parallel to the snorkel stentgraft. One year after the additional treatment, computed tomography (CT) revealed aneurysm sac shrinkage.ConclusionThe lift snorkel technique is a unique method converting the retrograde approach to antegrade renal artery stenting and would be an effective option for difficult trans-brachial cases for a type Ia endoleak after FEVAR of a JAAA.

Five-year results of the INSPIRATION study for the INCRAFT low-profile endovascular aortic stent graft system

ObjectiveWe present the 5-year results of a prospective regulatory study of the INCRAFT device, a low-profile endovascular stent graft system for repair of abdominal aortic aneurysms. MethodsThis was an open-label prospective nonrandomized single-arm study enrolling in centers in the United States and Japan. The primary effectiveness outcome was successful aneurysm treatment and the primary safety outcome was the incidence of major adverse events at 30 days after the procedure. Major long-term outcomes were mortality, reintervention, adverse limb outcomes, and suprarenal stent fracture. ResultsOne hundred and ninety patients (mean age, 73.8 ± 7.6 years; 90% male; 69% white and 30% Asian) were enrolled from 32 centers throughout the United States and Japan. Minimal access vessel size was less than 7 mm on both sides in 43.9% of the study cohort. Thirty-day major adverse events occurred in 3.2% of patients (6/190). Periprocedural technical success was 94.1% (176/187). Successful aneurysm treatment was 100% at 30 days and 87.9% at 1 year. Two patients required open conversion for thromboembolic complications, 3 developed new type I or III endoleaks, and 7 experienced graft or limb occlusion. Freedom from graft occlusion was 96 ± 2% at 1 year and 94 ± 2% at 5 years. Freedom from stent fracture was 97 ± 1% at 1 year and 87 ± 3% at 5 years. Freedom from aneurysm-related mortality was 99 ± 1% at 1 and 5 years. ConclusionsThis study demonstrates good efficacy and safety and a very low rate of aneurysm related deaths with the INCRAFT device in a population with a high proportion of challenging anatomy.

Endovascular Aortic Repair with the “Step-by-Step” Deployment of the Endurant Stent-Graft System in Severe Neck Angulation: Technique and Review of the Literature

To describe a new technique based on a different deployment of the Endurant Stent-Graft System (Medtronic Cardiovascular, Santa Rosa, CA) during endovascular aortic aneurysm repair to guarantee a more precise deployment in presence of severe neck angulation (SNA). The "step-by-step" deployment technique consists of an alternate partial release of the main body and of the free-flow suprarenal stents to approximate the radiopaque markers of the graft fabric to the aortic wall, obtaining a more precise delivery, reducing the possibility of downward dislodgments along the external curve of the infrarenal angle and asymmetrical deployments in presence of SNA. The "step-by-step" technique is a simple, safe, and effective graft-deployment method, which allows a very precise release in SNA and possibly achieves better results in the long-term period in such difficult anatomies.

Chimney with the Use of Nellix Device: An Alternative Solution for Type I Endoleak Treatment

Introduction - Endovascular aortic repair with chimney technique (Ch-EVAR) is commonly used in the treatment of type I endoleak when the patient is unsuitable for conversion to open surgery or custom made endograft implantation. Main issue with chimney technique is related to gutter endoleak; this risk may be reduced with the use of a Nellix device (Ch-EVAS), that could fill the gutter and reduce the incidence of type I endoleak. Methods - Sixteen consecutive patients (mean age 80.7 ± 7.0 years; 94% men) with prior EVAR were treated with ChEVAS between August 2015 and March 2018 in a single center. Indication for treatment was proximal type I endoleak in all patients, with associated neck dilation in 5 patients and migration in 5. The median diameter of residual aneurismal sac was 79.1 ± 2.4 mm The median time between original procedure and ChEVAS was 92.7±5.3 (range 1-148) months. Prior EVARs included different endografts (5 Zenith, 3 Endurant, 4 Talent, 1 Anaconda, 1 Fortron and 2 Nellix). In 12 patients (75%) preoperative CT scan showed the presence of suprarenal stent at the level of the visceral vessels. Two patients needed one chimney, ten patients needed double chimney and four patients needed three chimneys for a total of 34 target vessel overstented. In 30 visceral vessels a balloon expandable stent (Advanta atrium or Bentley BeGraft) was implanted, in the remaining 4 vessels a self-expandable stent (Viabahn Gore) was delivered. The Nellix endograft was implanted by bilateral percutaneous femoral approach in 11 patients Results - Technical success was achieved in 100% of the patients by completion angiography at the end of the procedure. No perioperative mortality was observed, one patient experienced non disabling posterior stroke at the end of the procedure. CT scan performed 1 month after the procedure showed sealing of 15/16 (94%) of type I endoleak , the remaining patient with residual proximal endoleak underwent a successful Onyx embolization one month later. At median follow-up of 13 months no recurrent endoleaks were recorded. All target vessel stented were patent with no need of reintervention. Conclusion - ChEVAS may serve as alternative treatment option in patients with type I endoleak where the implantation of fEVAR/brEVAR is hampered by the presence of previous endograt in site. Further follow-up and a multicenter study are needed to corroborate these preliminary results

In Vitro Evaluation of Balloon-Expandable Chimney Grafts in the Renal Arteries Combined With the Endurant Endograft

Purpose: To compare balloon-expandable covered stents (BECS) available for use as renal chimney grafts to the Advanta V12 approved for use with the Endurant endograft. Materials and Methods: A silicone model was manufactured based on preoperative computed tomography angiography (CTA) scans of a patient with a 7-cm juxtarenal aneurysm treated with an Endurant bifurcated endograft and an Advanta V12 covered stent for the 6-mm-diameter right renal artery. The model was placed in a flow box filled with a 37°C blood-mimicking solution equipped with a pulsatile pumping system (140/60 mm Hg). The tested BECS were the Advanta V12, the VBX, and the BeGraft+. A 36-mm-diameter Endurant II endograft with a 16-mm-diameter contralateral limb and a 6×59-mm BECS chimney graft were used in 9 consecutive tests (3 for each combination). After each implantation, the model was placed in the CT scanner, and 2 radiologists blinded to the test device independently measured the gutter areas and the patent chimney graft lumen at the level of the Endurant’s suprarenal stent, at the level of the chimney’s maximum curvature, and 10 mm inside the renal artery. The intraclass correlation coefficients (ICC) were calculated to assess interreader reliability. Results: The mean gutter areas were 19.3±7, 20.2±8, and 22.3±8 mm2 for the Advanta, VBX, and BeGraft+, respectively (all p>0.05). At the level of the aortic endograft’s suprarenal stent struts, the mean diameter of the Advanta V12, VBX, and BeGraft+ were 4.46±0.3, 4.12±0.4, and 4.12±0.3 mm, respectively (all p>0.05). At the level of the maximum chimney graft angulation, the mean diameters were 3.77±0.3, 4.16±0.1, and 3.74±0.3 mm, respectively (all p>0.05). In the right renal artery, the mean diameters were 3.91±0.2, 4.05±0.9, and 4.3±0.4 mm, respectively (all p>0.05). The ICCs varied between 0.7 and 0.9, indicating good agreement between readers. Conclusion: These in vitro findings showed comparable results between the Advanta V12 and the available BECS used in conjunction with the Endurant endograft according to the instructions for use. Further clinical evaluation is needed to confirm these results.

Reverse slider technique using the Endurant stent graft for accurate proximal sealing in hostile neck endovascular aneurysm repair

This report introduces the reverse slider technique to obtain proximal sealing effectively in endovascular aneurysm repair in short or angulated necks. It is the deployment process of the stent graft main body by repeatedly rotating and reversing the external slider with slight loosening of the suprarenal stent. This method helps obtain accurate placement of the proximal edge and effective sealing on the greater curvature side even in short and angulated necks. It is an effective method of extending the proximal sealing zone. It is gained by changing the deployment process with the Endurant stent graft (Medtronic, Santa Rosa, Calif) as an existing popular device.

Use of Synchrotron Radiation to Accurately Assess Cross-Sectional Area Reduction of the Aortic Branch Ostia Caused by Suprarenal Stent Wires

Purpose: To compare in vivo the use of synchrotron radiation to computed tomography angiography (CTA) for the measurement of cross-sectional area (CSA) reduction of the aortic branch ostia caused by suprarenal stent-graft wires. Methods: This study was performed with a Zenith stent-graft placed in a phantom of the human aorta to simulate treatment of abdominal aortic aneurysm. Synchrotron radiation scans were performed using beam energies between 40 and 100 keV and spatial resolution of 19.88 μm per pixel. CSA reduction of the aortic branch ostia by suprarenal stent wires was calculated based on these exposure factors and compared with measurements from CTA images acquired on a 64-row scanner with slice thicknesses of 1.0, 1.5, and 2.0 mm. Results: Images acquired with synchrotron radiation showed <10% of the CSA occupied by stent wires when a single wire crossed a renal artery ostium and <20% for 2 wires crossing a renovisceral branch ostium. The corresponding areas ranged from 24% to 25% for a single wire and from 40% to 48% for double wires crossing the branch ostia when measured on CT images. The stent wire was accurately assessed on synchrotron radiation with a diameter between 0.38±0.01 and 0.53±0.03 mm, which is close to the actual size of 0.47±0.01 mm. The wire diameter measured on CT images was greatly overestimated (1.15±0.01 to 1.57±0.02 mm). Conclusion: CTA has inferior spatial resolution that hinders accurate assessment of CSA reduction. This experiment demonstrated the superiority of synchrotron radiation over CTA for more accurate assessment of aortic stent wires and CSA reduction of the aortic branch ostia.

Comparison of Endovascular Stent Grafts for Abdominal Aortic Aneurysm Repair in Medicare Beneficiaries

Increased renal complications have been suggested with suprarenal stent grafts, but long-term analyses have been limited. Therefore, the purpose of this study was to evaluate the effect of endograft choice on perioperative and long-term outcomes. We compared Medicare beneficiaries undergoing endovascular abdominal aortic aneurysms repair from 2005 to 2008 with endografts with infrarenal fixation and a single docking limb (AneuRx, Excluder) to those with suprarenal fixation and 2 docking limbs (Zenith), or a unibody configuration (Powerlink). Propensity score weighting accounted for differences in patient characteristics among the different graft formations, and perioperative mortality, complications, and length of stay and 4-year rates of survival, rupture, and reintervention were compared. Forty-six thousand one hundred seventy-one Medicare beneficiaries were identified including 11,002 (24%) with suprarenal fixation, 32,909 (71%) with infrarenal fixation, and 2,260 (5%) with a unibody graft. After propensity score weighting, there were no significant differences in patients' baseline clinical and demographic characteristics. The suprarenal fixation patients had higher rates of perioperative mortality (1.7% vs. 1.3%, P<0.01), renal failure (6.0% vs. 4.7%, P<0.001), and mesenteric ischemia (0.7% vs. 0.4%, P<0.01) and longer length of stay (3.4days vs. 3.0days, P<0.001) compared with patients with infrarenal fixation. Unibody grafts had higher rates of renal failure (5.9% vs. 4.7%, P<0.001), mesenteric ischemia (1.0% vs. 0.4%, P<0.001), and conversion to open repair (0.7% vs. 0.1%, P<0.001) compared to those with infrarenal fixation and single docking limbs. At 4 years, mortality remained slightly higher with suprarenal compared to infrarenal fixation (30% vs. 29%, P=0.047), although these patients had fewer conversions to open repair (0.6% vs. 0.9%, P=0.03) and aneurysm-related reinterventions (10% vs. 12%, P<0.01). At 4 years, unibody grafts had more aneurysm-related interventions compared to infrarenal fixation grafts (15% vs. 12%, P<0.01) but fewer conversions to open repair (0.4% vs. 0.9%, P=0.02). Late rupture did not differ among the groups. Compared to infrarenal fixation devices, patients who underwent EVAR with suprarenal fixation had higher perioperative mortality and renal complications but fewer reinterventions including conversion, while the unibody graft had more perioperative complications and aneurysm-related reinterventions, but fewer conversions to open repair. Although these differences could be explained by selection bias, these data suggest that further comparative effectiveness analyses should be performed to understand the outcomes following EVAR with suprarenal fixation and unibody grafts.

Editor's Choice – Renal complications after EVAR with suprarenal versus infrarenal fixation among all users and routine users

BackgroundPrevious studies comparing endografts with suprarenal and infrarenal fixation for endovascular abdominal aortic aneurysm repair (EVAR) have found conflicting results and did not account for differences in patient selection. This study aims to evaluate the differences in outcomes among surgeons who routinely use either suprarenal or infrarenal fixation, as well as all surgeons in the Vascular Study Group of New England (VSGNE). MethodsAll patients undergoing EVAR in the VSGNE from 2003 to 2014 were identified. All ruptured aneurysms, repairs with concomitant procedures, and infrequently used stent grafts (<50) were excluded. Suprarenal endografts included Talent, Zenith, and Endurant; infrarenal endografts included AneuRx and Excluder. Grafts were compared among surgeons who used only one type of endograft (suprarenal or infrarenal) for >80% of cases, as well as all surgeons. Multivariate regression and Cox hazard models were utilised to account for patient demographics, comorbidities, operative differences, and procedure year. ResultsThis study identified 2574 patients (suprarenal, 1264; infrarenal, 1310) with 888 endografts placed by routine users (suprarenal, 409; infrarenal, 479). There were no differences in baseline comorbidities, including the estimated glomerular filtration rate, between suprarenal and infrarenal fixation, or between patients with endografts placed by routine and non-routine users. Patients treated with suprarenal endografts received more contrast than all users (102 mL vs. 100 mL, p = .01) and routine users (110 mL vs. 88 mL, p < .01), but other vascular and operative details were similar. Among all users, patients treated with suprarenal grafts had higher rates of creatinine increase >.5 mg/dL (3.7% vs. 2.0%, p = .01), length of stay >2 days (27% vs. 19%, p < .01), and discharge to a skilled nursing facility (9.2% vs. 6.7%, p = .02). There were no differences in 30 day or 1 year mortality. Following adjustment, suprarenal stent grafts remained associated with an increased risk of renal deterioration (OR 2.0; 95% CI 1.2–3.4) and prolonged length of stay (OR 1.8; 95% CI 1.4–2.2). Among routine users, suprarenal fixation was also associated with higher rates of renal dysfunction (3.7% vs. 1.3%, p = .02; OR 2.9; 95% CI 1.1–7.8). ConclusionDespite potential differences in patient selection, endografts with suprarenal fixation among all users and routine users were associated with higher rates of renal deterioration and longer length of hospital stay. Longer-term data are needed to determine the duration and severity of renal function decline and to identify potential benefits of decreased migration or endoleak.

Parallel Grafts Used in Combination with Physician-Modified Fenestrated Stent Grafts for Complex Aortic Aneurysms in High-risk Patients with Hostile Anatomies

The objective of the study was to evaluate the feasibility and early outcomes of complex aortic aneurysm repair in high-risk patients with hostile anatomies using both parallel stents and physician-modified stent graft (PMSG) techniques to address the renovisceral arteries. Consecutive patients with complex suprarenal (SRA) and thoracoabdominal aortic aneurysms (TAAAs) undergoing endovascular repair using combined parallel stents technique and PMSG between September 2013 and November 2015 were evaluated. All patients required prompt aneurysm treatment. Fenestrations to preserve branch vessels were created in thoracic stent grafts. Depending on the anatomy, chimney or snorkel stents were deployed in renal or visceral arteries as complementary technique to overcome severe angulations or preexisting suprarenal stent. Preoperative, intraoperative, and postoperative data were recorded by means of a prospectively maintained database. Six high-risk patients with TAAA (type I: n=2, type III: n=1) and SRA (n=3) underwent endovascular repair using both parallel stents technique and PMSG. Indications were painful aneurysms (n=1) and >70-mm rapidly enlarging aneurysms (n=5). Ten thoracic components were used, of which 6 were modified intraoperatively. Twenty-one renovisceral arteries were revascularized, using dedicated fenestrations (n=10, 47.7%), chimney (n=7, 33.3%), and snorkel stents (n=4, 19%). The mean operative time was 326 ± 82min including the device modification time. The mean time for graft modification was 90 ± 15min. In 1 patient, a rescue chimney stent intended to the superior mesenteric artery was deployed because of failed cannulation through the dedicated fenestration. Technical success rate was 83.3%. One patient died during the early postoperative course from severe stroke. Among surviving patients, 3 required early reinterventions for iliac occluder-related type II endoleak (n=1), type Ia endoleak (n=1), and gastroduodenal artery embolization (n=1). The mean follow-up was 14.2 ± 4.8months. One early gutter-related type I endoleak resolved during follow-up. No other complications occurred, and all target vessels remained patent. PMSG combined with parallel stent provided acceptable short-term results in specific presentation of SRA and TAAA with hostile anatomies in selected high-risk patients with contraindication for standard fenestrated/branched grafts. More reliable outcomes require larger population and follow-up.

Predictors of early aortic neck dilatation after endovascular aneurysm repair with EndoAnchors

ObjectiveDilatation of the aorta within the proximal neck after endovascular aneurysm repair (EVAR) can be associated with late endoleaks and migration. This study was designed to identify predictors of early neck dilation in patients undergoing EVAR with Heli-FX EndoAnchors (Medtronic, Santa Rosa, Calif) measured perioperatively to 1 year at different longitudinal levels of neck length. MethodsThe study group of Aneurysm Treatment Using the Heli-FX Aortic Securement System (ANCHOR) comprises 257 consecutive patients prospectively enrolled between April 2012 and September 2014 undergoing EVAR with Heli-FX EndoAnchor implantation at 38 investigational sites. Only patients undergoing EndoAnchor implantation at the time of the initial EVAR were included (primary treatment arm). Aortic diameter was measured at the suprarenal level and at three levels within the proximal neck. Neck dilatation was assessed in 209 patients with adequate computed tomography imaging at baseline and 1 month and in 62 patients at 1 month and 1 year (mean, 11.9 ± 4.0 months). Multivariable analyses were performed to identify independent predictors of perioperative (baseline to 1 month) and early postoperative (1 month to 1 year) aortic dilation at each level; analyses included 6 candidate variables, 6 clinical, and 14 anatomic run in eight models (one at each of the four aortic levels for both time frames). ResultsThe mean aortic neck dilation at 1 month was 0.2 ± 1.7 mm, 0.7 ± 2.2 mm, and 0.9 ± 3.6 mm at 0 mm, 5 mm, and 10 mm below the lowest renal artery, and 0.0 ± 1.5 mm at the suprarenal level. From 1 month to 1 year, neck dilatation was 0.5 ± 1.6 mm, 0.4 ± 1.5 mm, 0.2 ± 1.8 mm, and −0.3 ± 1.1 mm at the same four levels, respectively. Dilatation of ≥3 mm at level 5 mm distal to the lowest renal artery was observed in 26 patients (12.5%) from preoperative to 1 month and in 5 patients (8.1%) between 1 month and 1 year. Multivariable regression identified several variables predictive of perioperative (preoperative to 1 month) neck dilatation: baseline neck diameter, mural calcium (protective), and endografts with a suprarenal stent. Neck dilatation between 1 month and 1 year was associated with baseline neck diameter, neck length (protective), neck angulation, device oversizing, number of EndoAnchors implanted (protective), and endografts with a suprarenal stent. ConclusionsAortic diameter and graft oversizing appear to be independent risk factors for early aortic neck dilatation. EndoAnchors have a protective effect on neck dilatation at their usual level of deployment.

Comparison of Renal Complications between Endografts with Suprarenal and Infrarenal Fixation

Surgeons have multiple grafts options available for the endovascular treatment of abdominal aortic aneurysm (EVAR), and some hypothesize that suprarenal fixation endografts may result in higher rates of renal complications than infrarenal endografts. This study aimed to compare the outcomes of contemporary suprarenal and infrarenal endografts. The Targeted Vascular Module of the National Surgical Quality Improvement Project was utilised to identify patients undergoing EVAR for infrarenal aneurysm from 2011 to 2013. Pre-operative and operative variables and 30 day outcomes were compared among suprarenal (Zenith and Endurant) and infrarenal fixation devices (Excluder). Renal complications included creatinine increase > 2mg/dL or new dialysis, as defined by NSQIP. Multivariate regression was completed to account for patient demographics, comorbidities, and operative characteristics. A total of 3587 patients were evaluated including 2273 (63%) with suprarenal grafts and 1314 (37%) with infrarenal grafts. Patients with suprarenal grafts were less commonly white (84% vs. 88%, p<.01) and more commonly male (83% vs. 80%, p=.03). There were no differences in age or comorbidities. Renal complications (1.1% vs. 0.1%, p<.01) and length of stay more than 2 days (34% vs. 25%, p<.01) occurred more commonly after suprarenal fixation. After adjustment, suprarenal grafts had significantly higher rates of renal complications (OR, 12.0; 95% CI, 1.6-91) and length of stay more than 2 days (OR, 1.4; 95% CI, 1.2-1.7). Overall rates of renal complications following EVAR are low. Patients selected for suprarenal stent grafts are at increased risk of renal complications and prolonged length of stay, which may be due to selection bias, deployment techniques, or the presence of a bare stent overlying the renal arteries. Further studies are necessary to evaluate the mechanism and duration of renal dysfunction and important long-term outcomes of interest.

Push-Up Technique and Anatomical Deployment With the Endurant Stent-Graft System for Severely Angulated Aneurysm Necks

Purpose: To describe a technique suitable for treating severely angulated (>75°) necks during endovascular aneurysm repair using the Endurant stent-graft. Technique: In the push-up technique, the suprarenal stent is released early to fix the proximal stent-graft in place so that each stent in the neck can be deployed individually without displacing the device upward. It is important to push the delivery system up after each stent deployment to allow the fabric between the stents to fold up circumferentially. By doing so, there is minimal upward force applied to the suprarenal stent. Because the stents expand along the angulated neck while catching blood flow, this anatomical deployment is feasible, with hardly any change to the proximal neck shape after stent-graft implantation. Conclusion: The push-up technique and anatomical deployment with the Endurant stent-graft system are effective and safe methods for treating aneurysms with severely angulated necks.

Pulse Wave Analysis after Treatment of Abdominal Aortic Aneurysms with the Ovation Device

Ovation aortic stent-graft system is a new device for the endovascular treatment of Abdominal Aortic Aneurysms achieving fixation via a 35-mm long, rigid anchored suprarenal stent and sealing stent at the infrarenal level by a means of a polymer-filling pair of inflatable O-rings, which cause narrowing of flow lumen and regional stenosis. Thus, concerns have been raised regarding hemodynamic consequences associated with this new design. Our preliminary report showed no significant increase of aortic pulse wave velocity (aPWV) immediately after implantation of the ovation in 3 patients. We studied further the hemodynamic implications of the Ovation implantation in 6 patients for a follow-up of 6months. A brachial cuff-based automatic oscillometric device (Mobil-O-Graph; IEM, Stolberg, Germany) was used to perform noninvasively pulse wave analysis and stiffness estimation. Measurements were held preoperatively in 6 patients treated for abdominal aortic aneurysm, at the end of the first postoperative week, first and sixth postoperative month. Changes in systolic and diastolic blood pressure (cSyst, cDiast), heart rate, aPWV, augmentation index (AI@75), augmentation pressure (AP), and in the amplitude ratio of the reflected-to-forward pressure waves (reflection magnitude, RM) were recorded and compared. Significant change in any parameter was examined via analysis of variance repeated measures. The cSyst was 132±19.6, 127±17.63, 131.3±19.96, and 129.83±31.72mm Hg (P= 0.81) and cDiast was 88±10.58, 86.83±11.72, 89.83±16.01, and 98.5±24.56mm Hg (P= 0.40). The heart rate showed an increasing yet nonsignificant tendency (67±10.60, 75.1±8.63, 74.33±8.89, and 70.66±6.65 beats/min, 0.27). The aPWV remained constant (11.61±1.88, 11.6±1.74, 11.8±2.08, and 11.85±2.30m/sec, P = 0.79). Similarly, RM (71.16±9.94, 60.66±11.79, 61.5±14.47, and 64.5±3.78), AI@75 (33.83±12.25, 22.16±7.93, 27.83±11.23, and 19.5±14.72), and AP (18.33±10.36, 9.83±4.91, 11.5±9.22, and 12±15.08mm Hg) remained practically unaltered during the follow-up period (P value: 0.79, 0.25, 0.10, and 0.27), respectively. The implantation of the Ovation stent graft does not cause increase in aortic stiffness or in pulse wave reflection in the mid-period. The rationale of investigating noninvasively the impact of aortic stent grafts on the mechanical properties and the hemodynamic parameters should be encouraged because such findings may contribute to further development of newer endograft designs.

Disintegration of the Top Stent on Zenith Abdominal Aortic Stent-Grafts

Purpose: To describe a heretofore unreported complication involving the Zenith Low Profile (LP) stent-graft. Case Report: Two men, aged 75 and 67 years, respectively, underwent abdominal aortic aneurysm repair with a Zenith LP device. At 4 and 3 years, respectively, computed tomography angiography revealed separation of the proximal fixation stent from the stent-graft. In the first patient, there was stent-graft migration but no evidence of an endoleak; however, the aneurysm had grown. A fenestrated cuff was placed, sealing distally in the previous LP graft. The second patient had a type I endoleak. Open surgery was performed, and the main body of the graft was explanted. Postoperative examination of the device revealed that the fixation sutures on the suprarenal stent were still attached to the stent and had eroded through the graft material. Conclusion: Physicians should be aware of the potential for top stent separation from the Zenith LP stent-graft as a cause of endoleak and migration.