Prevalence of type II endoleak after elective endovascular aneurysm repair with polytetrafluoroethylene- or polyester-based endografts.

OBJECTIVE: Type II endoleak is the most frequent complication after endovascular abdominal aneurysm repair. Polytetrafluoroethylene and polyester (PE) are the two most commonly used graft materials in endovascular aneurysm repair (EVAR) devices. Biological properties of the material might influence the appearance and persistence of type II endoleak (T2EL). Therefore, the aim of this study was to evaluate potential differences in the prevalence of T2EL after EVAR between polytetrafluoroethylene (PTFE) and PE endografts in patients electively treated for an infrarenal abdominal aortic aneurysm. METHODS: A single-center, retrospective, observational study was conducted between January 2011 and January 2022. Preoperative, procedural, and follow-up data were derived from electronic health records. Imaging included computed tomography scans, and/or duplex ultrasound examination. The primary end point was the prevalence of T2EL diagnosed within 1 year after EVAR. Secondary end points included the prevalence of T2EL throughout follow-up, early (≤30 days) and late (>30 days) T2EL, the rate of T2EL disappearance during the follow-up period, the prevalence of type I and III endoleak, and T2EL-related reinterventions. RESULTS: Follow-up was available for 394 patients, 245 in the PE and 149 in the PTFE group. The prevalence of T2EL diagnosed within 1 year after endovascular repair was 11.8% in the PE group and 21.5% in the PTFE group (P = .010). There was no significant difference in early (≤30 days) and late (>30 days) T2EL between groups (P = .270 and P = .311). There was no difference in the freedom from endoleak type II reinterventions between groups (P = .877). CONCLUSIONS: The prevalence of T2EL after elective EVAR is significantly higher with the use of PTFE-based endografts compared with PE-based endografts. This difference is mostly based on T2EL diagnosed after 30 days of follow-up.

Systematic review of risk factors and outcomes of post-implantation syndrome following endovascular aortic repair.

OBJECTIVE: Post implantation syndrome (PIS) is an early systemic inflammatory response following endovascular aortic repair (EVAR). The response is variable in patients and the clinical significance of PIS upon outcomes is unknown. This study aims to evaluate the incidence, risk factors, and prognostic implication of PIS. METHODS: Systematic literature review and analysis was performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and Cochrane guidelines of PubMed, Scopus, ClinicalTrials.gov, and the Cochrane Central Register of Controlled Trials. Eligible English-language studies regarding PIS after infrarenal EVAR were included, after removing duplicates. RESULTS: After screening, 31 studies were included. A total of 2847 patients were reviewed, with mean age of 70.7 years, of which 2012 (90.4%) were male, with a pooled mean follow-up of 26.1 months. PIS was reported in 25.3% of cases, with mean aneurysm diameter of 56.4 cm. Polytetrafluoroethylene (PTFE) grafts were utilized in 794 patients (27.9%) with polyester in 1839 (64.6%). White blood cell count, C-reactive protein, interleukin (IL)-6, IL-8, and IL-10 levels were all significantly elevated postoperatively. Thirty-day outcomes included type I endoleak rate of 0.8%, type II endoleak rate of 1.7%, reintervention rate of 0.35%, and mortality rate of 0.25%. Subgroup pooled analysis of patients with PIS (n = 309) vs No-PIS (n = 691) revealed that polyester (n = 642), rather than PTFE (n = 234) grafts, were associated with a higher rate of PIS (94.8% vs 3.7%; P = .0001), White blood cell count was higher in the PIS group both preoperatively (7.61 vs 6.76 × 109/L; P = .04) and postoperatively (15.0 vs 9.8 × 109/L; P = .0007) and IL-6 levels were higher in the PIS group postoperatively (98.6 vs 25.2 pg/mL; P = .02). Aneurysm diameter and amount of chronic or new thrombus within the aneurysm sac was not identified as a risk factor for PIS. Pooled outcomes of patients with PIS vs No-PIS demonstrated a significantly higher rate of 30-day mortality (0.6% vs 0%; P = .03) and major adverse cardiac events (5.8% vs 0.43%; P < .0001) without any differences seen in reintervention or 30-day type I or type II endoleaks. CONCLUSIONS: This systematic review suggests that polyester grafts are strongly associated with PIS compared with PTFE. Interestingly, this report is suggestive of an association between 30-day mortality and major adverse cardiac events and PIS. Given these clinical sequelae, consideration for use of PTFE over polyester grafts to reduce the incidence of PIS may be a simple step to improve overall outcome. Further, exploration of the relationship between inflammatory mediators associated with PIS and mortality and cardiac complications may engender deeper understanding of risks, leading to eventual mitigation of harm for patients experiencing PIS.

Injection of n-Butyl-2-Cyanoacrylate into the Abdominal Aortic Aneurysm Sac during Endovascular Aortic Repair to Prevent Type II Endoleaks Caused by Lumbar Arteries.

PURPOSE: To evaluate midterm results of whether the strategy to occlude target lumbar arteries using n-butyl-2-cyanoacrylate (nBCA) injection during endovascular aneurysm repair (EVAR) reduced the incidence of Type II endoleak (T2EL) after EVAR. MATERIALS AND METHODS: Between 2013 and 2020, 187 patients underwent EVAR; 106 in the treatment group received nBCA injection during EVAR, whereas 81 in the historical control group did not. The incidence of T2EL at 7 days, need for reintervention, and post-EVAR aneurysmal shrinkage were compared between the groups. RESULTS: Between the treatment group and the control group, significant differences were achieved in the incidence of T2EL (2.8% vs 28.4%; P < .0001) and decreased aneurysmal diameter was observed at 1 year after EVAR (-5.2 vs -3.8 mm; P = .034). In multivariate analysis, nBCA injection (odds ratio [OR], 0.04; P = .001) and younger age (OR, 0.92; P = .036) were significantly associated with a reduced incidence of T2EL. As a possible adverse event associated with nBCA injection, 2 cases of transient lower-limb motor dysfunction (1.9%) were observed. Propensity score analysis revealed that the treatment group had a significantly lower incidence of T2EL than that in the control group (P = .0002) even though there was no difference in the incidence of inferior mesenteric artery coil embolization between the groups. The survival rate without aneurysm sac enlargement (100.0% vs 69.8%; P = .014) and the reintervention-free rate (100.0% vs 63.1%; P = .034) in the treatment group were significantly higher than those in the control group. CONCLUSIONS: Concomitant nBCA injection can provide durable EVAR without T2EL, as supported by the avoidance of reintervention associated with aneurysm sac enlargement.

Midterm Outcomes of Antegrade In Situ Laser Fenestration of Polyester Endografts for Urgent Treatment of Aortic Pathologies Involving the Visceral and Renal Arteries.

OBJECTIVE: Aortic endografting and antegrade in situ laser fenestration of visceral arteries (LFEVAR) may be considered as an alternative to open surgery for the emergency repair of complex abdominal aortic aneurysms (AAA) in fragile patients. The aim of this article was to evaluate the midterm results of LFEVAR performed with polyester endografts. METHODS: From August 2015 to December 2020, all consecutive LFEVAR performed for non-deferrable treatment of complex AAA were analysed. Polyester endografts were deployed and subsequently fenestrated using an atherectomy laser probe; the fenestrations were enlarged using cutting and semicompliant balloons before implantation of balloon expandable bridging stents into the target vessels. Prospectively collected midterm survival, patency, and re-intervention rates were analysed. RESULTS: Forty four procedures were performed for 11 type 1a endoleaks, five thoraco-abdominal aneurysms, 20 pararenal aneurysms, four segmental renal artery (RA) preservations, three anastomotic aneurysms, and one aortic dissection. One hundred and eight laser fenestrations were performed (26 for the superior mesenteric artery [SMA], 13 for the coeliac trunk, 33 and 31 for the right and left RA, respectively). The median ischaemia duration was 7, 48, 48, and 45 minutes, respectively. The technical success rate was 97%, with no open surgical conversions. The 30 day mortality was 4.5% (n = 2). No spinal cord ischaemia events were observed nor early stent related complications. Kaplan-Meier overall survival at two years was 73%, the aortic related re-intervention free survival was 70%, and the stent related re-intervention free survival was 90.6%. Four target vessel thromboses were detected, of which three were rescued. Three type IIIc endoleaks, one RA false aneurysm, and one SMA stenosis, required re-intervention during a median follow up of 24.7 months. CONCLUSION: Antegrade LFEVAR is feasible, safe, and provides satisfactory early and midterm outcomes for non-deferrable treatment of aortic pathologies involving the visceral segment. Long term data are mandatory to confirm the usefulness of this promising off label technique.

Cryopreserved Arterial Allografts Versus Rifampin-Soaked Dacron for the Treatment of Infected Aortic and Iliac Aneurysms.

BACKGROUND: Infected aortic and iliac artery aneurysms are challenging to treat. Cryopreserved arterial allografts (CAAs) or rifampin-soaked Dacron (RSD) are standard options for in situ reconstruction. Our aim was to compare the safety and effectiveness of CAA versus RSD for these complex pathologies. METHODS: This is a retrospective review of infected iliac, abdominal, and thoracoabdominal aortic aneurysms treated with either CAAs or RSD between 2002 and 2022 at our institution. The diagnosis was confirmed by intraoperative, radiologic, or microbiological evidence of aortic infection. Perioperative events, 30-day and long-term mortality, reinfection, and reintervention were analyzed. RESULTS: Thirty patients (17 CAA, 13 RSD) with a mean age of 61 and 68 years, respectively, were identified. The infected aneurysm was most commonly suprarenal or infrarenal. Culture-negative infections were present in 47% of the CAA group and 54% in the RSD group. Early major morbidity was 57% and 54% for the CAA and RSD, respectively. Thirty-day mortality was similar between groups (18% vs. 23% CAA vs. RSD, P ≥ 0.99). Median follow-up was longer in the RSD group (14.5 months vs. 13 months). Overall survival at 1 and 5 years was 80.8% and 64.8% in the CAA group and 69.2% and 57.7% in the RSD group. Reinterventions only occurred with CAA repairs and indications included graft occlusion (2), multiple pseudoaneurysms and reinfection (1), and hemorrhagic shock caused by graft rupture (1). Freedom from reintervention at 1 and 3 years was 87.5% and 79.5% (CAA group) versus 100% and 100% (RSD, P = 0.06). Freedom from reinfection at 1 year was 100% in both groups, while at 3 years it was 90.9% for the CAA group and 100% for the RSD group (P = 0.39). CONCLUSIONS: Infected aortic and iliac aneurysms have high early morbidity and mortality. CAA and RSD had similar outcomes in our series; CAA trended toward higher reintervention rates. Both remain viable options for complex scenarios but require close surveillance.

Onyx™ Cast Fragmentation After Embolization of Endoleaks.

PURPOSE: Endoleaks are common following endovascular aneurysm repair (EVAR), and the liquid embolic material Onyx has been widely used in their treatment. We report our experience of long-term morphological changes of Onyx casts on surveillance imaging. MATERIALS AND METHODS: We identified 10 patients over 10 years who underwent Onyx embolization in our institution. Morphological changes of Onyx casts were assessed on surveillance radiographs and computed tomography (CT) scans. Relevant outcome data and sequelae were obtained via electronic patient records. RESULTS: Twelve procedures were performed on 10 cases, 9 for type 2, and 1 for a type 1a endoleak. Five cases showed evidence of Onyx fragmentation on follow-up imaging ranging from a single fracture to gross fragmentation with migration of fragments. Of these 5, 3 had achieved primary success but 2 went on to develop recurrence of endoleak. Onyx volume ranged from 4 to 46.5 ml (median 10.5 ml) per patient with larger volumes demonstrating the most marked fragmentation on follow-up. Follow-up ranged from 9 months to 8 years (median 2.25 years). CONCLUSION: To our knowledge, this is the first report of Onyx fragmentation after endoleak embolization. If long-term morphological stability of the Onyx cast is necessary to maintain aneurysm seal, then Onyx may not offer a permanent solution to some patients with post-EVAR endoleaks. Our study cannot ascertain whether the observed changes were the cause or the effect of ongoing aneurysm growth, persistent endoleak, and/or other forces acting on the solidified polymer, but it raises important questions on the use of Onyx in this setting.

"Aortic Balloon Molding" during Ovation Endograft Implantation Expands Graft Use for Hostile Neck Anatomy.

BACKGROUND: Challenging aortoiliac anatomy such as short neck and narrow access vessels is responsible for endovascular repair of abdominal aortic aneurysm (EVAR) ineligibility in up to 50% of cases. The Ovation stent graft helped widen the range of abdominal aortic aneurysms (AAAs) suitable for EVAR thanks to its low-profile delivery system and polymer-filled sealing rings. However, its advantages are offset by a tight sizing chart that can lead to increased risk of type Ia endoleak or endograft infolding from under- or oversizing, respectively. We sought to assess the safety and efficacy of a novel endovascular technique developed to expand the use of the Ovation endograft while avoiding these issues. METHODS: We conducted a retrospective review of all patients who underwent EVAR with the Ovation endograft at our institution between March 2019 and December 2020. "Aortic Balloon Molding" or ABM is a novel endovascular technique in which the graft is pre-cannulated and a compliant aortic balloon is inflated at the site of the graft's sealing rings during polymer administration. The technique was preferentially performed in patients with hostile neck anatomy (HNA) defined as any or all of angulation >60°, reverse taper configuration, ≥50% circumferential thrombus, or calcification. Patients undergoing traditional deployment were compared to those in whom ABM was performed. End points included neck-related adjunctive procedures, technical success, type Ia endoleak at completion angiogram, and 1-year freedom from type Ia endoleak and migration. RESULTS: A total of 43 patients were included in the study, of which 26 (60.5%) were treated with the ABM technique. Mean follow-up was 7.9 ± 6 months. Patients in the ABM group were more likely to have a reverse taper neck (61.5% vs. 41.2%, P = 0.1), have significant circumferential thrombus or calcium (23.1% vs. 5.9%, P = 0.1), and be treated outside of the Ovation indications for use regarding anatomic characteristics (65.4% vs. 41.2%, P = 0.1). Technical success was achieved in 100% of cases. However, patients in the ABM group were less likely to require a neck-related adjunctive procedure (7.7% vs. 23.5%, P = 0.1). Only 1 type Ia endoleak was observed at completion angiogram in a patient treated without ABM. At 1 year, freedom from type Ia endoleak or migration was 100% for both groups. CONCLUSIONS: ABM proves to be a safe and effective adjunctive technique for the treatment of AAAs with HNA using the Ovation stent graft. This may allow optimal endograft sizing to achieve adequate seal in complex aortic anatomies. Further research is warranted to evaluate the long-term outcomes of this technique.

Cutaneous hydrophilic polymer emboli following endovascular repair of an abdominal aortic aneurysm: a case and review of literature.

Hydrophilic polymer embolism (HPE) is a rare iatrogenic complication of the use of polymer-coated intravascular devices, which may affect several organ systems including the skin. Herein, we present a patient who developed a cutaneous eruption with associated neurologic manifestations secondary to localized HPE. This is a potentially underdiagnosed, life-threatening complication and physicians should consider HPE when evaluating skin eruptions in patients who have undergone endovascular procedures.

Outcomes of translumbar embolization of type II endoleaks following endovascular abdominal aortic aneurysm repair.

OBJECTIVE: Presence of an endoleak can compromise aneurysm exclusion after endovascular abdominal aortic aneurysm repair (EVAR). Type II endoleaks (T2Es) are most common and may cause sac expansion. We report outcomes of translumbar embolization (TLE) of T2Es following EVAR. METHODS: We conducted a retrospective chart review of patients with T2E after EVAR treated with TLE from 2011 to 2018 at a single academic institution. Treatment indications were the presence of persistent T2E and aneurysm growth ≥5 mm. Sac stabilization was defined as growth ≤5 mm throughout the follow-up period. RESULTS: Thirty consecutive patients were identified. The majority were men (n = 24), with a mean age of 74.3 years (95% confidence interval [CI], 70.9-77.6 years). The most common comorbidities were hypertension (83.3%) and coronary artery disease (54.0%). The mean maximal sac diameter at T2E discovery was 5.8 cm (95% CI, 5.4-6.2 cm). The mean time to intervention from endoleak discovery was 33.7 ± 28 months with a mean growth of 0.84 cm (95% CI, 0.48-1.2 cm) during that time period. The mean follow-up time after TLE was 19.1 months (95% CI, 11.1-27.2 months). Twenty-eight patients were treated with cyanoacrylate glue (CyG) alone, and two were treated with CyG plus coil embolization (CE). There was immediate complete endoleak resolution as assessed intraoperatively, and sac stabilization in 15 cases (50.0%). Eleven patients (36.7%) had evidence of persistent T2E on initial imaging after the embolization procedure; additional follow-up revealed eventual sac stabilization at a mean of 21.3 ± 7.2 months, and therefore, these patients did not require further intervention. In the remaining four cases (13.3%), there was persistent T2E after the initial TLE, requiring a second intervention. Repeat TLE stabilized growth in three of these four patients after a mean of 17.6 ± 12.9 months. One patient required open sacotomy and ligation of lumbar vessels due to continued persistence of the T2E and continued aneurysm growth. There were no ischemic complications related to the embolization procedures. Factors associated with persistent endoleak after initial embolization were larger aneurysm diameter at the time of initial endoleak identification (P < .001) and the use of antiplatelet agents (P < .02). The use of anticoagulation was not a significant risk factor for endoleak recurrence or aneurysm growth after TLE. CONCLUSIONS: TLE of T2E is a safe and effective treatment option for T2E with aneurysm growth following EVAR. Patients taking antiplatelet medication and those with larger aneurysms at the time of endoleak identification appear to be at increased risk for persistent endoleak and need for subsequent procedures following initial TLE. These patients may require more intensive monitoring and follow-up.

Onyx versus coil embolization for the treatment of type II endoleaks.

OBJECTIVE: Little evidence is available supporting the optimal treatment of type II endoleaks associated with aortic sac growth. Previous studies have lacked comparisons between treatment methods and long-term follow-up. The purpose of the present study was to review our center's experience with the treatment of type II endoleaks comparing Onyx (a liquid embolization agent consisting of ethylene vinyl alcohol; Medtronic, Minneapolis, Minn) embolization and coil embolization. METHODS: A retrospective review of prospectively collected data from a vascular surgery database was performed to identify all patients who had undergone embolization of a type II endoleak for aortic sac growth after endovascular aneurysm repair from 2005 to 2018. The Onyx and coil embolization groups were compared using univariate statistics. RESULTS: A total of 58 patients had undergone 77 embolization procedures for type II endoleaks with either Onyx (27 patients; 37 procedures) or coils (31 patients; 40 procedures). The average aneurysm size at embolization was larger in the Onyx group (77.9 ± 15.1 mm) compared with coil embolization (73.4 ± 11.9 mm). The mean follow-up was 57 months for the Onyx group and 74 months for the coil embolization group. Of the 27 patients who had undergone Onyx embolization, 2 (7.4%) had required graft explantation compared with 5 of the 31 patients (16.1%) who had undergone coil embolization (P = .33). The results of the per-patient analysis showed that the coil embolization group had a significantly greater rate of the need for further reintervention compared with the Onyx group (55% vs 19%; P < .01). Clinical success was observed in 13 patients (48%) in the Onyx embolization group compared with 10 patients (32%) in the coil embolization group (P = .04). Two patients in each group had presented with secondary rupture of the aneurysm sac after attempted embolization. CONCLUSIONS: Type II endoleaks associated with sac growth treated with Onyx were less likely to require further reinterventions than were those treated with coil embolization. A trend was found toward a greater need for endovascular aneurysm repair explant after coil embolization. With a high rate of further reintervention and potential for sac rupture, diligent follow-up is required after attempted type II embolization, regardless of the technique used.

Systematic review of embolization of type I endoleaks using liquid embolic agents.

OBJECTIVE: The long-term success of endovascular aneurysm repair (EVAR) is limited by complications, most importantly endoleaks. In case of (persistent) type I endoleak (T1EL), secondary intervention is indicated to prevent secondary aneurysm rupture. Different treatment options are suggested for T1ELs, such as endo anchors, (fenestrated) cuffs, embolization, or open conversion. Currently, the treatment of T1EL with liquid embolic agents is available; however, results are not yet addressed. This review presents the safety and efficacy of embolization with liquid embolic agents for treatment of T1ELs after EVAR. METHODS: A systematic literature search was performed for all studies reporting the use of liquid embolic agents as monotherapy for treatment of T1ELs after EVAR. Patient numbers, technical success (successful delivery of liquid embolics in the T1EL) and clinical success (absence of aneurysm related death, endoleak recurrence or additional interventions during follow-up) were examined. RESULTS: Of 1604 articles, 10 studies met the selection criteria, including 194 patients treated with liquid embolics; 73.2% of the patients were male with a median age of 71 years. The overall technical success was 97.9%. Clinical success was 87.6%. Because the median follow-up was only 13.0 months (range, 1-89 months), data on long-term success are almost absent. Four cases (2.1%) of secondary aneurysm rupture after embolization owing to endoleak recurrence were reported. All ruptures occurred in aneurysms exceeding initial treatment diameter of 70 mm. CONCLUSIONS: Initial technical success after liquid embolization for T1EL is high, although long-term clinical success rates are lacking. Within this review, the risk of secondary rupture is comparable with untreated T1EL at 2% with a median follow-up of 13 months, regardless of the initial success of embolization. In general, no decrease in secondary aneurysm rupture after embolization of T1EL after EVAR is demonstrated, although the results of late embolization are debated.

Modeling and Computational Comparison of the Displacement Forces Exerted between the AFX Unibody Aortic Stent Graft and its Hybrid Combination with a Nitinol-based Proximal Aortic Cuff.

BACKGROUND: The bifurcated AFX (Endologix, Inc, Irvine, CA, USA) aortic stent-graft is the sole unibody endograft for the management of Abdominal Aortic Aneurysms (AAA). In order to improve the AFX central sealing and clinical efficacy in challenging cases, a replacement of the central chromium-cobaltium AFX extension with a Nitinol-based proximal aortic cuff has been suggested. Yet, comparative data regarding the hemodynamic performance of this design is missing. Aim of this study was to compare the displacement forces (DF) acting on the hybrid AFX-Endurant design, with the classic AFX and Endurant endografts, in angulated and non-angulated cases based on patient-specific Computational Fluid Dynamics (CFD) simulations. METHODS: 3D endograft models of 11 treated AAA cases were reconstructed from Computed Tomography Angiography (CTA) imaging data: 5 cases of AFX, 3 cases of the combination AFX-Endurant and 3 cases of the classic Endurant design. The DF on the main-body, the iliac limbs, and the entire stent-graft was calculated by processing the velocity and pressure fields generated by pulsatile CFD simulations. RESULTS: The range of total DF (acting on the whole endograft structure) in the AFX, hybrid AFX-Endurant and Endurant group was 2.5-5.2N, 2.0-5.9N and 1.9-2.9N respectively, with the maximum total DF being lower for Endurant. The DF on the main-body of the classic and hybrid AFX cases were higher than the right and left iliac limbs (2.5-4.9N vs. 0.6-5.3N and 0.7-3.6N respectively). Conversely, the DF on the main-body of the Endurant cases was comparable to the force exerted on the right and left limbs. When separating the cases with respect to their neck angulation, the DF on all endograft parts (main-body, limbs) and on the endograft as a whole were lower for the hybrid AFX-Endurant group compared to the classic AFX and Endurant groups, for cases with almost straight neck. CONCLUSION: The off-label use of the hybrid AFX-Endurant stent-graft does not seem superior to the conventional AFX or Endurant endografts in angulated cases but was associated with lower DF than AFX or Endurant in non-angulated cases. The clinical value and utility of these findings remain to be elucidated.

The Potential Relation Between polytetrafluoroethylene Grafts after Open Reconstructions for Abdominal Aortic Aneurysm and Perigraft Seromas.

BACKGROUND: The presence of sac enlargement after abdominal aortic aneurysm (AAA) open repair, a condition usually called perigraft seroma (PGS), nearly always has a benign behavior. Some theories implicated for PGS formation include coagulation abnormalities, fibroblast inhibition, low-grade infection, or improper graft handling. METHODS: This is a retrospective study including patients treated for AAA in 2 academic vascular surgery departments from 2007 to 2014, where 1 center preferably used polytetrafluoroethylene (PTFE) grafts whereas the preference of other center was mostly Dacron graft. The definition of PGS was conceived as a fluid collection around the graft on CT scan imaging with a radiodensity ≤25 Hounsfield units, reaching at least 30 mm in diameter and beyond the third postoperative month. Analysis was performed between patients with and without PGS. RESULTS: Seventy-eight patients met the inclusion criteria: 42 received Dacron and 36 PTFE grafts. Twenty-three (29.5%) patients accomplished the PGS diagnosis. Having a PTFE graft was the strongest factor for PGS formation on multivariate analysis. The medium seroma size was 42 mm (range, 30-90.6 mm) and the mean time from AAA repair to PGS detection was 26 months (range, 4-106 months). Three patients of the 23 with PGS required surgical repair, all of them were successfully treated: 2 by endovascular means and the remaining with explantation and Dacron reconstruction. CONCLUSIONS: PGS formation is not an unusual complication after open reconstructions for AAA treatment. This is especially true for PTFE grafts, and thus, closer follow-up is warranted if using this material. Treatment is clearly needed when symptoms appear; however, preventive strategies with either endovascular relining or reopen reconstructions require an individual approach counterbalancing benefits versus risk of the procedures.

Polyester Stent Graft Devices and Higher Risk of Post-Implantation Syndrome after EVAR: Single-Center Analysis of 367 Patients.

BACKGROUND: The post-implantation syndrome may occur shortly after endovascular aneurysm repair in patients treated for abdominal aortic aneurysm. Different types of biomaterials may provoke varying inflammatory responses in patients receiving different endografts. The purpose of this article is to evaluate the PIS after EVAR and the influence of different types of device fabric. METHODS: All patients submitted to elective AAA endovascular repair at our institution from January 2014 to December 2019 were enrolled. The PIS was defined by a body temperature of >38°C and WBC >12'000/µl without any evidence of an infection during (48h) the observation period. RESULTS: Three hundred and sixty-seven patients (89% males) were enrolled in this study and post-implantation syndrome occurred in 41 cases (11.2%). The incidence of PIS was significantly higher (P< 0.001) in patients treated with polyester stent grafts (39/201, 19,4%) compared to patients with PTFE stent grafts (2/166, 1,2%). CRP was related to the presence of PIS with a cut-off values of 109.31 mg/dL (P = 0.0052). The median in-hospital stay considering the polyester group was 6,2 days, while in the PTFE group it was 5,6 days (P = 0.04). CONCLUSIONS: The postoperative inflammatory response after EVAR seems significantly higher by using polyester stent graft compared to PTFE devices. CRP could be a useful biomarker in defining PIS. Multi-center studies are necessary to confirm these data.

Polymer based endografts have improved rates of proximal aortic neck dilatation and migration.

BACKGROUND: Proximal aortic neck dilatation (PND) affects a considerable proportion of patients undergoing endovascular aneurysm repair (EVAR) and is associated with increased rates of type I endoleak (EL1), migration, and reinterventions. Although there are numerous studies investigating PND following the placement of endografts that utilize self-expanding stent (SES) technology, there are few reports for patients treated with endografts that utilize polymer-filled rings. The purpose of this study is to examine PND and graft migration after EVAR with the Ovation stent graft. METHODS: The study comprised patients who underwent EVAR as part of the prospective, international, multicenter Ovation stent graft trial. A clinical events committee adjudicated adverse events through 1 year, an independent imaging core laboratory analyzed imaging through 5 years, and a data safety and monitoring board provided study oversight. Neck diameter was measured at the level of the lowest renal artery. PND was defined as neck enlargement of 3 mm or more. Graft migration was defined as distal movement >10 mm or movement ≤10 mm when resulting in secondary intervention. RESULTS: A total of 238 patients received this device during the study period. Patients were predominantly male (81%), with a mean age of 73 ± 8 years. Median follow-up was 58 months (IQR 36-60). Almost half the patients (110 patients, 46%) had challenging anatomy; defined as outside the instructions for use (IFU) with other commercially available stent grafts. 41 patients (17.2%) had a proximal neck length <10 mm and 93 (39%) had a minimum access vessel diameter <6 mm. The technical success rate was 100%. The 1-, 3- and 5-year overall survival rates were 96.6%, 86.2% and 74.9%, respectively. The immediate postoperative proximal neck diameter ranged from 16 mm to 31 mm with a mean of 22.4 ± 3 mm. During follow-up, ten patients (4.2%) developed PND. Freedom from PND estimates at 1, 3 and 5 years were 97.7%, 96%, and 93.6%, respectively. None of the patients developed endograft migration. CONCLUSIONS: The use of the Ovation stent graft was associated with low rates of PND despite challenging neck anatomy in 17% of patients. No graft migration was observed. The design of this endograft may explain its superiority to SES in preventing neck dilatation and migration even in patients with challenging neck anatomy. This is important, as we continue to see significant late failures of EVAR due to proximal neck degeneration.

Use of Heparin-Bonded Expanded Polytetrafluoroethylene Grafts for Renal Artery Reconstruction.

BACKGROUND: The purpose of this study was to analyze our initial experience in renal artery reconstruction with heparin-bonded expanded polytetrafluoroethylene (ePTFE) grafts. METHODS: The authors retrospectively reviewed the data of consecutive patients who received open renal reconstruction with a heparin-bonded ePTFE graft at our institution between January 2014 and December 2019. RESULTS: A total of 22 renal reconstructions with a heparin-bonded ePTFE graft were performed in 17 consecutive patients. In all cases, renal reconstruction was a concomitant procedure during surgical or endovascular aortic procedures. Postoperative complications within 30 days were observed in 9 (53%) patients, including acute kidney injury (n = 6), pneumonia (n = 1), retrograde type B aortic dissection (n = 1), and lower limb ischemia (n = 1). The 30-day mortality rate was 0%. In a median follow-up period of 32 (19-39) months, all grafts were patent without re-intervention. Six patients with preoperative stage 2 chronic kidney disease progressed to stage 3 during follow-up. No patient required temporary or permanent hemodialysis. One patient died from intestinal ischemia at 23 months after surgery. CONCLUSIONS: This study showed that the patency after open renal reconstruction with a heparin-bonded ePTFE graft was excellent, with acceptable renal outcomes, and demonstrates its safety as a concomitant procedure during an aortic procedure. Heparin-bonded ePTFE grafts are a feasible and effective choice for open renal reconstruction in contemporary practice.

Final results from a postmarket registry of an iliac leg graft with a continuous, spiral nitinol stent.

OBJECTIVE: To evaluate clinical outcomes from a postmarket registry of the Zenith Spiral-Z abdominal aortic aneurysm iliac leg graft with a continuous, spiral nitinol stent that was designed for improved conformability, kink, and migration resistance. METHODS: This prospective, multicenter registry was designed to evaluate physician-reported outcomes of the Spiral-Z leg graft in up to 600 patients who underwent endovascular repair of abdominal aortic or aortoiliac aneurysms at up to 30 investigative sites in the United States and Canada. Study outcomes were focused on iliac limb occlusion, limb-related reintervention, limb-related endoleak, component separation, and device integrity. Short-term data were collected during an interval of 1 to 6 months, with longer term data collected at 12 months. RESULTS: Between March 2012 and March 2015, 599 patients (mean age 74 ± 8 years; 87% male; 26% with aortoiliac aneurysm) were treated, with Spiral-Z iliac leg grafts placed in 564 left iliac arteries and 559 right iliac arteries. The mean iliac inner diameters (both left and right) were 9 ± 3 mm; moderate/severe occlusive disease, calcification, and vessel tortuosity were present in 14%, 25%, and 36% and 15%, 25%, and 34% of the left and right iliac arteries, respectively. Iliac artery adjunctive procedures (iliac artery angioplasty and/or stent placement) were performed intraoperatively in 112 patients (19%; bilateral in 52 patients). Mortality within 30 days was 1.7% (10/599); cumulative mortality at 1 year was 6.2% (37/599). There were no aortic ruptures and only one open conversion (0.2%). Limb occlusions occurred in 11 of 599 patients (2%; 3 within 30 days and 8 after 30 days, all unilateral, none had received procedural iliac artery adjuncts at implantation); of these, 7 patients underwent reinterventions. Other limb-related reinterventions were performed on eight patients for nonocclusive kink, compression, or thrombus (six within 30 days and three after 30 days). In total, 13 patients (2%) underwent 15 limb-related reinterventions (7 for occlusions and 8 for nonocclusive causes). In one patient, a distal type I endoleak and device migration (>10 mm) involving a right iliac leg was noted at the 12-month follow-up visit. No other limb-related endoleak, migration, component separation, or stent fracture was reported during a mean follow-up of 11 ± 6 months. CONCLUSIONS: The Spiral-Z leg graft demonstrated excellent patency and required infrequent limb-related reinterventions in routine clinical care in a postmarket registry.

Outcomes of Onyx® Embolization of Type II Endoleaks After Endovascular Repair of Abdominal Aortic Aneurysms.

BACKGROUND: Type II endoleaks (T2ELs) are common following endovascular repair of abdominal aortic aneurysms (EVAR). Embolization with ethylene vinyl alcohol copolymer (Onyx) may present an effective treatment alternative for T2ELs. Due to limited data supporting its use, we sought to analyze outcomes of Onyx embolization for T2ELs. METHODS: Retrospective review of consecutive patients treated for T2ELs utilizing Onyx embolization agent from 2009-2018. All pre- and post-Onyx intervention CT scans were analyzed for diameter and volume changes with 3D reconstruction software. The primary outcomes were change in maximum AAA diameter and volume. Secondary outcomes included additional interventions, rupture, and mortality. A subset analysis was performed with patients with isolated T2ELs (no other types of endoleaks present). RESULTS: We identified 85 patients (73 males, mean age 77.6 ± 7.6 years) who underwent 112 Onyx interventions. Average time to first Onyx intervention after index EVAR was 3.3 ± 2.6 years and average sac growth was 6.3 ± 6.7 mm. Patients underwent mean 1.3 Onyx interventions using a mean of 4.9 ± 4.7 ml for treatment. Three complications occurred (Onyx extravasation, colon ischemia, and access site hematoma). Mean follow-up was 2.5 ± 2.1 years after initial Onyx treatment. At the most recent follow-up, sac diameter stabilization was seen in 47% and reduction >5 mm was seen in 19%. Sac growth of >5 mm was seen in 34% of patients following the first Onyx intervention. In our subset of isolated T2EL, 72% had sac stabilization or reduction >5 mm. Four patients experienced a ruptured aneurysm (3 had active type 1 endoleaks). Rupture-free survival was 95% at 5 years, and overall survival was 54% at 5 years. Notably, increasing Onyx interventions were not associated with sac stabilization or reduction (OR 0.6, P = 0.1). On multivariable analysis, AAA sac diameter stabilization or reduction was independently associated with BMI >30 kg/m2 (OR 4.2, P = 0.01) and having only 1 Onyx intervention (OR 3.8, P = 0.02). CONCLUSIONS: Onyx for embolization of T2ELs resulted in AAA sac diameter stabilization or reduction in 66% of patients, and up to 72% in isolated T2ELs. Further, increasing Onyx interventions were not associated with either aneurysm sac stabilization or reduction. Given its similar outcomes to other embolization strategies in the literature, Onyx embolization for management of T2ELs needs to be judiciously considered, particularly for T2ELs persisting after an initial Onyx embolization intervention.

Endovascular Aortic Aneurysm Repair without Type 2 Endoleak Using Concomitant N-Butyl-2-Cyanoacrylate Injection into the Abdominal Aortic Aneurysm Sac.

BACKGROUND: The aim of this study was to evaluate our new method to occlude target lumber arteries using N-butyl-2-cyanoacrylate (NBCA) during endovascular aneurysm repair (EVAR) for prevention of type 2 endoleak (T2E). METHODS AND RESULTS: Between 2013 and 2018, 176 patients who underwent EVAR for abdominal aortic aneurysm (AAA) were reviewed. Starting from October 2015, 83 patients (treatment group) underwent NBCA injection into the aneurysmal sac during EVAR. The incidence of T2E at 7 days and AAA sac diameter 12 months after EVAR were compared with those of the control group comprising 93 consecutive patients who underwent EVAR alone before 2015. The incidence of T2E at 7 days was significantly lower in the treatment group (2.4%) than in the control group (22.6%) (P < 0.001). AAA sac diameter at 12 months in the treatment group had a mean decrease of 6.6 mm as compared with the mean 4.4 mm in the control group (P = 0.026). In multivariate analysis, NBCA injection was significantly related to the reduction of incidence of T2E at 7 days (odds ratio = 11.8, P < 0.001) and a decrease in AAA sac diameter at 12 months (P < 0.001). There was no NBCA injection-related complication and reintervention in the treatment group. CONCLUSIONS: NBCA injection might be safe and useful to reduce the incidence of T2Es and to prevent AAA sac expansion.

Image-Based Displacements Analysis and Computational Blood Dynamics after Endovascular Aneurysm Repair.

BACKGROUND: To examine intraheartbeat displacements (IHD) and geometrical changes of endografts for abdominal aortic aneurysm repair over the course of years, defined as follow-up displacements (FUD), and to correlate them with computational fluid dynamics (CFD). Despite the widespread use of endovascular aneurysm repair (EVAR), we still know little about endograft behavior after deployment. METHODS: Two cases, treated with either expanded polytetrafluoroethylene on a nitinol stent frame (PI) or with woven polyester fabric sutured to a stainless-steel Z stent skeleton (PII), were submitted to dynamic computed tomography angiography at 1, 12, and 60 months after implantation. After segmentation, IHD were computed as displacements of the reconstructed surface with respect to the diastolic instant. Similarly, FUD were studied using imaging techniques that align temporal successive segmentations. In addition, numerical simulations for blood dynamics were performed to compute viscous forces, specifically wall shear stress and time-averaged wall shear stress (TAWSS). RESULTS: IHD analysis showed slight translations without deformation for the PI endograft with respect to the stiffer stainless-steel endograft behavior of PII. FUD showed in PI motion of the metallic struts mainly focused on the distal main body of the endograft and in the zone overlapping with iliac branches. In PII, we observed a huge FUD in the middle and inferior-anterior regions of the main body. CFD analysis revealed changes of velocity patterns associated with remodeling of the iliac zone for PI and of the main body region for PII, where flow impinges the lumen wall and progressively induces deformation of the endograft wires. Measurement of TAWSS demonstrated flow disturbances in the enlarged region correlated with displacement analysis. CONCLUSIONS: Image-based displacement analysis associated with CFD enabled very subtle evaluations of endograft behavior on different temporal scales. This kind of study could be helpful both for physicians, forecasting evolution during the life span of the endograft, and manufacturers, giving them useful information about endograft implant performance and design.