Impact of suprarenal neck angulation on endovascular aneurysm repair outcomes

Friendly Neck Anatomy Does Not Prevent Neck-Related Adverse Events After EVAR

BACKGROUND

Life-long follow-up after endovascular aneurysm repair (EVAR) is costly and burdensome to the patient. Follow-up should be stratified based on the risk of EVAR failure. Aneurysm neck is thought to be the single most important risk factor. This study investigated neck anatomy as a predictor of neck-related adverse events after EVAR.

METHODS

This retrospective single-center study included consecutive patients undergoing elective EVAR for infrarenal abdominal aortic aneurysms between 2011 and 2016 (n = 222) who were followed with yearly imaging until December 2020. Hostile neck was defined as neck length ≤15 mm, width ≥28 mm, angulation ≥60°, calcification, or thrombus ≥50% of circumference or conical neck based on preoperative computed tomography angiography. Neck-related adverse event was defined as aneurysm rupture, any neck-related reintervention or type 1a endoleak during follow-up.

RESULTS

Ninety (41%) patients had hostile neck and 132 (59%) had friendly neck. There were no differences in 30-day mortality (1% vs. 1%, P = 0.78), major adverse events (20% vs. 16%, P = 0.43) or reinterventions during the hospital stay (8% vs. 4%, P = 0.20) between patients with hostile and friendly neck. Estimated survival at 1 year was 89 ± 3% for hostile neck and 95 ± 2% for friendly neck patients (P < 0.01). Five-year survival estimates were 51 ± 6% and 66 ± 4%, respectively. Aneurysm-related mortality was higher after 6 years in patients with hostile neck (P < 0.01). Twenty-four patients (11%) suffered neck-related adverse events with mean time-to-event of 3.3 ± 2.8 years; there were no differences between the groups stratified by neck anatomy. Incidentally, preoperative aneurysm diameter was found to be an independent risk factor for neck-related adverse events and aneurysm-related mortality; 53 patients (24%) had aneurysm diameter ≥70 mm, which was associated with nearly 4-fold risk of neck-related complications during the follow-up.

CONCLUSIONS

Friendly neck anatomy may not protect from neck-related adverse events after EVAR in the long-term. Especially patients with large aneurysms should be followed closely.

Incidence of endoleak type IA in patients undergoing chimney endovascular aortic repair (ChEVAR) vs. standard endovascular repair

Objectives

Almost half of endovascular aortic aneurysm repair (EVAR) procedures are performed in hostile anatomy, increasing the risk of procedure related complications such as type IA endoleaks, which may be prevented with the chimney technique in EVAR (ChEVAR). Our aim is to describe the differential characteristics between EVAR in favorable anatomy and ChEVAR in hostile necks.

Materials and methods

A cohort of patients with infrarenal abdominal aortic aneurysms (AAA) that were treated with EVAR or ChEVAR were included. The primary outcome was the incidence of type IA endoleak. Secondary outcomes were the rate of chimney occlusion, reintervention, migration, rupture, acute limb ischemia, sac growth, and aneurysm-related mortality during the follow-up period.

Results

. With a median follow-up of 11.5 months, 79 patients were treated with EVAR and 21 with ChEVAR. The overall age was 76.49 ± 7.32 years old, and 82% were male. The ChEVAR cohort had a higher prevalence of tobacco use than the EVAR cohort (38.1% vs. 17.7%, p = 0.041), and a shorter neck (7.88 mm ± 5.73 vs 36.28 mm ± 13.73, p<0.001). There were no differences in type IA endoleak incidence between the groups (a single endoleak type IA in the EVAR group, p = 0.309). One patient experienced an asymptomatic chimney occlusion in the ChEVAR group, and another patient required a reintervention due to chimney occlusion. Sac regression and reinterventions were not different between groups. There were no migration, rupture, acute limb ischemia, or aneurysm-related mortality events.

Conclusions

. In patients with abdominal aortic aneurysms, ChEVAR in hostile necks had similar event rates to EVAR in favorable necks.

Technical pitfalls and proposed modifications of instructions for use for endovascular aortic aneurysm repair using the Gore Excluder conformable device in angulated and short landing zones

We describe a case of an abdominal aortic aneurysm (AAA) and angulated proximal neck treated with a Gore Excluder conformable endoprosthesis and show relevant technical pitfalls in the deployment of the graft main body. An 82-year-old man presented with a 71-mm asymptomatic AAA with an angulated infrarenal proximal neck (75°) and was referred to our unit. The patient was treated with a 26-mm Gore Excluder conformable device, which was deployed slightly above the renal arteries after precatheterization of the lowest renal artery. The graft was then repositioned with support of the introducer sheath and a stiff guide wire. The proximal sealing zone was ballooned before the endograft delivery system was retrieved to avoid distal migration. Technical success was achieved. The patient was discharged with no complications. No type Ia endoleak was present on the 6-month computed tomography scan. Endovascular treatment of an AAA with a severe angulated proximal neck can be effective with a conformable stent graft if technical measures are used during deployment of the main body to optimize the seal.

Postendovascular Aneurysmal Repair Increase in Local Energy Loss for Fusiform Abdominal Aortic Aneurysm: Assessments With 4D flow MRI

BACKGROUND

Although endovascular aneurysmal repair (EVAR) is a preferred treatment for abdominal aortic aneurysm (AAA) owing to its low invasiveness, its impact on the local hemodynamics has not been fully assessed.

PURPOSE

To elucidate how EVAR affects the local hemodynamics in terms of energy loss (EL).

STUDY TYPE

Prospective single-arm study.

FIELD STRENGTH/SEQUENCE

A 3.0 T/4D flow MRI using a phase-contrast three-dimensional cine-gradient-echo sequence.

POPULATION

A total of 13 consecutive patients (median [interquartile range] age: 77.0 [73.0, 78.8] years, 11 male) scheduled for EVAR as an initial treatment for fusiform AAA.

ASSESSMENT

4D flow MRI covering the abdominal aorta and bilateral common iliac arteries and the corresponding stent-graft (SG) lumen was performed before and after EVAR. Plasma brain natriuretic peptide (BNP) was measured within 1 week before and 1 month after EVAR. The hemodynamic data, including mean velocity and the local EL, were compared pre-/post-EVAR. EL was correlated with AAA neck angle and with BNP. Patients were subdivided into deformed (N = 5) and undeformed SG subgroups (N = 8) and pre-/post-EVAR BNP compared in each.

STATISTICS

Parametric or nonparametric methods. Spearman's rank correlation coefficients (r). The interobserver/intraobserver variabilities with Bland-Altman plots. A P value < 0.05 is considered significant.

RESULTS

The mean velocity (cm/sec) at the AAA was five times greater after EVAR: 4.79 ± 0.32 vs. 0.91 ± 0.02. The total EL (mW) increased by 1.7 times after EVAR: 0.487 (0.420, 0.706) vs. 0.292 (0.192, 0.420). The total EL was proportional to the AAA neck angle pre-EVAR (r = 0.691) and post-EVAR (r = 0.718). BNP (pg/mL) was proportional to the total EL post-EVAR (r = 0.773). In the deformed SG group, EL (0.349 [0.261, 0.416]) increased 2.4-fold to 0.848 (0.597, 1.13), and the BNP 90.3 (53.6, 105) to 100 (67.2, 123) post-EVAR.

CONCLUSION

The local EL showed a 1.7-fold increase after EVAR. The larger increase in the EL in the deformed SG group might be a potential concern for frail patients.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 2.

Long-term Results of Angulated Versus Hyperangulated Neck in Endovascular Aneurysm Repair With Endurant Endoprosthesis

PURPOSE

Patients with a hyperangulated (>60°) proximal aortic neck and at high risk of open surgery have been treated with endovascular aortic repair (EVAR). However, long-term outcomes are not well reported. The aim of this study is to compare the technical and clinical success of EVAR in angulated (45°-60°) and hyperangulated (>60°) proximal neck angulation.

MATERIALS AND METHODS

The data of all consecutive patients undergoing EVAR treated between November 2007 and February 2020 were collected. A retrospective analysis of this prospective database was performed. The primary measure outcome was technical and clinical success. In addition, we evaluated sack evolution, type IA endoleak, secondary procedures, aneurysm rupture, mortality, aneurysm-related mortality, and migration.

RESULTS

In all, 246 of 1353 EVAR patients presented with an angulation of the proximal neck >45°, 130 patients presented with an infrarenal angulation >60°, while 116 patients had an angulation between 45° and 60°. Patients with a hyperangulated infrarenal aortic neck were significantly more often women (8.6% vs 26.9%), older (73.9 vs 76.7 years), and had less often diabetes mellitus (20.7% vs 10.8%). Suprarenal neck angulation and reversed tapered neck were significantly more frequent in the hyperangulated group so that propensity scores were generated using these anatomical parameters to create a matched cohort group. No significant differences in technical (87.9% vs 94.8%) and clinical success (66.4% vs 69.8%) were observed. After a mean clinical follow-up of 58.9 months significantly more secondary procedures were performed in the hyperangulated group (23.3% vs 12.9% p=0.04); however, neck-related secondary procedures were comparable (1.7% vs 6.0%; p=0.09). Also, all-cause and aneurysm-related mortality, sack evolution, type IA endoleak, aneurysm rupture, and migration were comparable for both groups.

CONCLUSION

Compared with less angulated proximal aortic neck, hyperangulated neck anatomy did not reduce the technical and clinical success of EVAR but increased the risk of secondary procedures. In patients who are not good candidates for open surgery, EVAR is a reasonable alternative.

DANCER: Study protocol of a prospective, non-randomized controlled trial for crossed limb versus standard limb configuration in endovascular abdominal aortic aneurysm repair

Background

Hostile anatomy, especially severely angulated neck and tortuous iliac arteries, has always been a conundrum in endovascular aneurysm repair (EVAR). Crossed limb (CL) graft, also called the “ballerina technique,” has been utilized to address this problem by facilitating gate cannulation. In terms of short and long-term outcomes, correlated studies have made inconsistent conclusions and this issue remains controversial. Based on a previous cohort study conducted in our center, we aim to prospectively compare the safety and efficacy between CL and standard limb (SL) configuration in patients receiving EVAR.

Methods

This is a prospective, single-center, non-randomized controlled trial. A total of 275 patients who meet the inclusion criteria will be enrolled and allocated with a 4:11 ratio of CL to SL, which is based on results of our previous study. All patients will receive same perioperative management and postoperative medications. All EVAR procedures will be performed under standard protocol, utilizing Endurant II or IIs Stent Graft. The configuration of the graft stent will be decided by surgeons and confirmed by final angiography. The primary outcome is 3-year freedom from major adverse limb-graft events (MALEs). Endpoints will be assessed at the following time points: 1, 6, 12, 24, and 36 months.

Discussion

To our best knowledge, this crosseD vs. stANdard Configuration in Endovascular Repair (DANCER) trial is the first non-randomized controlled trial to compare these two graft configurations in EVAR. The main aim is to compare the MALEs between two groups at 3 years postoperatively. This trial will hopefully provide high-level evidence for employing CL in EVAR.

Clinical trial registration

[www.chictr.org.cn], identifier [ChiCTR2100053055].

Pre-operative Aortic Neck Characteristics and Post-operative Sealing Zone as Predictors of Type 1a Endoleak and Migration After Endovascular Aneurysm Repair: A Systematic Review and Meta-Analysis

OBJECTIVE

Establishing the predictive value of neck characteristics and real achieved sealing zone is essential to foster risk stratified procedure selection and imaging surveillance. This systematic review provides an overview of pre-operative aortic neck characteristics and post-operative real achieved sealing zone and their respective risk of type 1a endoleak and migration after endovascular aneurysm repair (EVAR).

METHODS

In agreement with PRISMA guidelines, MEDLINE, Embase, and Cochrane CENTRAL were searched. Data on neck characteristics, sealing zone, and EVAR outcome were extracted. Meta-analyses were performed to investigate the effect of neck diameter, angulation, and shape on type 1a endoleak (total, early ≤ 90 days, and late > 90 days) and migration in patients who underwent EVAR. A qualitative summary was also provided.

RESULTS

Thirty-three studies were included. Patients with a larger neck diameter had an increased risk of total type 1a endoleak (nine studies: OR 3.32, 95% CI 2.38 - 4.63), early type 1a endoleak (six studies: OR 2.64, 95% CI 1.27 - 5.48), late type 1a endoleak (six studies: OR 3.26, 95% CI 2.12 - 5.03), and migration (seven studies: OR 2.88, 95% CI 1.32 - 6.26). An angulated neck increased the risk of total type 1a endoleak (seven studies: OR 4.27, 95% CI 1.55 - 11.78) and late type 1a endoleak (seven studies: OR 5.56, 95% CI 2.19 - 14.13). Neck shape was not associated with type 1a endoleak. Neck length and real achieved sealing zone on post-EVAR computed tomography were identified as risk factors for type 1a endoleak and migration through qualitative summary.

CONCLUSION

There seems to be some consistent evidence that aortic neck diameter, angulation, and length are associated with the development of type 1a endoleak or migration. Real achieved sealing zone might be an important addition during follow up. However, a small number of studies, with serious limitations, could be included, and there was considerable variability in reporting patients and outcomes. A proposal for standardisation of aortic and EVAR data in future studies is provided.

EVALUATION OF AORTIC TORTUOSITY AS A NEGATIVE PREDICTOR OF ABDOMINAL AORTIC ANEURYSM RUPTURE

OBJECTIVE

Maximal aortic diameter has been used as a key indication to repair an abdominal aortic aneurysm (AAA). Aortic tortuosity has been proposed as another consideration. This study compared the degree of aortic tortuosity in ruptured aneurysms with those who underwent elective repair using CT imaging.

METHODS

A retrospective review of a prospectively maintained database of patients that underwent AAA repair from Dec 2014 to Dec 2019 was undertaken. Patients with ruptured aneurysm (rAAA) were matched to a group of non-ruptured AAA (nrAAA) patients with the same maximal aneurysm diameter and age. The degree of aortic tortuosity, defined as the maximum lateral deviation (mm) from aortic centerline, was measured on preoperative CT scans on coronal views.

RESULTS

Over a 5-year period, 572 AAA cases were identified. The aortic tortuosity of 25 rAAA cases were compared with a matched control group of 31 nrAAA that were selected based on same mean maximum diameter of 8.4cm and similar age. In the rAAA group, the mean age was 74.8 years (84% males). For the nrAAA group, the mean age was 76.3 years (88%) males. The mean aortic tortuosity for the rAAA cases and nrAAA groups were 9.3±7.9 mm and 18.0±11.2 mm, respectively (p<0.01).

CONCLUSIONS

Greater aortic tortuosity was seen in nrAAA cases compared with rAAA cases at the same matched aneurysm size. This suggests that aortic tortuosity may confer a reduced rupture risk. Further studies with larger cohorts are needed to verify this observation.

The Correlation Of Aortic Neck Length To Late Outcomes Following EVAR with the Ovation Stent Graft

BACKGROUND

Endovascular aneurysm repair (EVAR) performed outside manufacturers' instructions for use (IFU) due to short aortic neck for the treatment of abdominal aortic aneurysm (AAA) is associated with unfavorable outcomes. Newer endografts now have an indication for shorter neck aneurysms that previous endografts do not, but this cohort has yet to be evaluated individually. The aim of this study is to evaluate 5-year outcomes after EVAR in patients with short aortic necks (<10mm) using the Ovation stent graft.

METHODS

The study comprised 238 patients who underwent EVAR as part of the prospective international multicenter Ovation stent graft trials. The main inclusion criteria were AAA diameter ≥ 5cm, proximal parallel neck length ≥7mm, neck angulation ≤60° and bilateral iliac fixation length ≥10 mm. 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. Patients were divided into short neck (<10mm) and standard neck (≥10mm) groups. Endpoints included long-term survival, freedom from aneurysm-related mortality (ARM), freedom from type Ia Endoleak and freedom from reintervention.

RESULTS

Patients were predominantly male (81%) with a mean age of 73±8 years. Median follow-up time was 58 months (IQR 36-60). Out of 238 patients, 41 (17.2%) had a proximal neck length <10mm and would be considered outside the IFU with other stent grafts. Baseline characteristics were relatively similar between the two groups. The 5-year overall survival estimates were 77.8% for the standard neck group compared to 59.5% for the short neck group (P= .03) (Figure1). There were no differences in the 5-year freedom from ARM (99.2% vs. 100%, P= .7), freedom from type Ia Endoleak (96.3% vs. 96.3%, P= .8) and freedom from reintervention (77.9% vs. 79.7%, P= .7) between the standard and short neck groups, respectively. After adjusting for age and other potential confounders, short proximal neck was associated with a 2-fold increase in 5-year all-cause mortality [aHR(95%CI): 2(1.02-3.8), P= .04].

CONCLUSION

The Ovation endograft performed well in short AAA neck with no difference in 5-year type Ia Endoleak, reintervention and ARM rates. However, short proximal neck was independently associated with a two-fold increase in the risk of all-cause mortality at five years. These findings confirm the prior literature on the association of hostile neck anatomy with late mortality following EVAR.

Predictive value of elliptical neck parameters and oversizing ratio for type Ia endoleaks after endovascular aneurysm repair

OBJECTIVE

To assess the predictive value of elliptical geometric parameters regarding type IA endoleak (T1AEL) after endovascular aneurysm repair (EVAR) and investigate optimal range of oversizing ratio (OSR) in patients with elliptical aneurysmal neck.

METHODS

In this propensity-score matched case-control study, case patients were those diagnosed with T1AEL, control patients were those who did not have T1AEL after EVAR in the same period from 2012 to 2018. Geometric and oversizing parameters were compared based on both 2D and 3D measurement. Net reclassification improvement (NRI) was used to measure prediction increment of elliptical model (major axis OSR, neck length and severe neck angulation (SNA)) compared to conventional model (OSR 2D, neck length and SNA).

RESULTS

Nineteen case patients and 111 control patients were included. The median OSR 2D of T1AEL patients were 17% (15%-22%), but the median major axis OSR were only 7% (5%-12%). Among geometric parameters, axis difference had the highest area under the curve (AUC) of 0.74 (95%CI 0.63-0.84) in predicting T1AEL. As for elliptical oversizing parameters, major axis OSR had an AUC of 0.89 (95%CI 0.78-0.97) with a cut-off value of 13%. Elliptical model had higher discriminating ability in T1AEL compared to conventional model (AUC 0.91 vs 0.86, P=0.045), with improved reclassification ability (NRI 27.93%, 95% CI 19.22%-36.64%, P<0.0001).

CONCLUSION

Elliptical aneurysmal neck, assessed by axis difference, is associated with an increased risk of T1AEL. Calculation of oversizing based on major axis for at least 13% can significantly reduce the risk of T1AEL in patients with elliptical aneurysmal neck.

Late Type 1A Endoleaks: Associated Factors, Prognosis and Management Strategies

BACKGROUND

Unlike periprocedural Type 1A endoleaks, late appearing proximal endoleaks have been poorly described.

METHODS

We studied all elective EVAR from 2010 -2018 in a single institution. Late endoleaks were defined as those appearing after 1 year. We used Cox regression to study factors associated with late Type 1A endoleaks and survival.

RESULTS

Of 477 EVAR during the study period, 411 (86%) had follow-up imaging, revealing 24 Type 1A endoleaks; 4 early and 20 late. Freedom from Type 1A endoleaks was 99%, 92-81% at 1, 5 and 8 years with a median time to occurrence of 2.5 years (.01-8.2 years). On completion angiogram, only 10% of patients with a late Type 1A had a proximal endoleak, and 60% had no endoleak. Only 21% of late Type 1As were diagnosed on routine 1-year CT angiogram, but 79% had stable or expanding sacs. Two thirds (65%) of the patients eventually diagnosed with late Type 1A endoleaks had previously been treated for other endoleaks, mostly Type 2 (10/13). Age (HR 1.07/year [1.02-1.12], P = 0.01), neck diameter >28mm (HR 3.5 [1.2-10.3], P = 0.02), neck length <20mm (HR 3.0 [1.1-8.6], P = 0.04), and neck angle>60 degrees (HR 3.4 [1.5-7.9], P = 0.004) were associated with higher rates of Type 1A endoleak, but not female sex, endograft, or the use of suprarenal fixation. 2 patients had proximal degeneration and 5 experienced graft migration. There were 2 ruptures (10%), and 13 patients underwent repair with 5 open conversions. Median survival after late Type 1A repair was 6.6 years (0-8.4 years).

CONCLUSION

Late appearing Type 1A endoleaks have a high rate of rupture and present significant diagnostic and management challenges. Careful surveillance is needed in patients with hostile neck anatomy and those who undergo intervention for other endoleaks. Adverse neck anatomy may be better suited for open repair or fenestrated/branched devices rather than conventional EVAR.

Effect of vertebral compression fractures on aortic neck angulation after endovascular aneurysm repair

OBJECTIVE

Aortic neck angulation (ANA) prior to endovascular aneurysm repair (EVAR) and its changes after EVAR are considered important predictors of postoperative complications. We sought to assess the effects of vertebral body height loss on ANA in patients post-EVAR.

METHODS

All patients who had undergone EVAR for infrarenal aortic aneurysms in our institution between August 2010 and December 2018 were assessed. Anterior and posterior vertebral body heights were measured in all patients on preoperative, early postoperative, and follow-up computed tomography scans (T12-L5 vertebral bodies). Patients who had significant height loss in their follow-up period were designated as the Study group. These were matched to a Control group of the same size using propensity-score matching based on age, gender, and duration between follow-up scans. Aortic neck morphology indices including ANA and its changes were measured, and information related to postoperative endoleaks and aneurysm sac size were extracted in the Study and Control groups.

RESULTS

During the follow-up period, 10 of 185 patients had a radiologically significant vertebral body compression fracture. There was no significant difference between the Study (n = 10) and Control groups in age (77.6 ± 6.9 vs 77.2 ± 7.5 years; P = .64), gender (seven males and three females in each group; P = 1.0), duration between postoperative scans (1830 ± 665 vs 1800 ± 670 days; P = .25), preoperative ANA (36.0° ± 15.6° vs 42.4° ± 18.6°; P = .41), and early postoperative ANA (21.9° ± 11.7° vs 20.9° ± 16.3°; P = .72). Changes in ANA in the postoperative period (7.2° ± 11.1° vs -4.7° ± 6.7°; P = .009; power = .838) were significantly higher in the Study group.

CONCLUSION

Post-EVAR vertebral body compression fractures exacerbate ANA. Awareness of this can guide both preoperative assessment and postoperative management and follow-up.

Outcomes of Endovascular Aneurysm Repair with Adjunctive Stenting

OBJECTIVE

Endovascular aneurysm repair is the standard of care for abdominal aortic aneurysm repair, however data regarding adjunctive stenting at the time of endovascular aneurysm repair (EVAR) are limited. The study aims to evaluate outcomes of patients undergoing EVAR with and without adjunctive stenting.

METHODS

Patients undergoing EVAR with stenting (EVAR-S) and without stenting (EVAR) (2008 to 2017) were selected from Cerner HealthFacts® database using ICD-9 diagnosis and procedure codes. Chi-square analysis and multivariable logistic regression were used to evaluate the association of patient characteristics with medical and vascular outcomes.

RESULTS

4,957 patients undergoing EVAR procedures were identified (3,816 EVAR and 1,141 EVAR-S). Demographic analysis revealed that patients who underwent EVAR-S had higher Charlson comorbidity scores (2.35 vs. 2.13, p = .0001). EVAR-S was associated with a greater frequency of vascular complications such as thrombolysis/percutaneous thrombectomy (0.9% vs. 0.2%; p < .0004). There were no differences seen in access complications between EVAR and EVAR-S. Multivariable analysis revealed that EVAR-S was associated with prolonged length of stay (OR 1.37, 95% CI 1.03-1.82), readmission < 30 days (OR 1.36, 95% CI 1.11-1.68), major adverse cardiac events (OR 1.59, 95% CI 1.09-2.32), respiratory complications (OR 1.47, 95% CI 1.16-1.88) and renal failure (OR 1.57, 95% CI 1.16-2.11).

CONCLUSIONS

Endovascular aneurysm repair with adjunctive stenting (EVAR-S) was associated with vascular complications requiring reintervention, although the overall rate was very low. As well, readmission within 30 days, cardiac complications, respiratory problems and renal failure were more likely when compared to standard EVAR. The need for adjunctive stenting acts as a marker for an overall sicker and more complex population, not just in terms of vascular complications but across all medical complications as well. Staging the procedure may be helpful in terms of spreading out the operative risk into smaller portions. Furthermore, consideration of a non-operative strategy should be discussed with the patient if the risk of the procedure outweighs the risk of aneurysm rupture in high-risk groups.

Use of Chimney Technique Does Not Improve the Outcome of Endovascular Aneurysm Repair in Patients With a Hyperangulated and Short Proximal Aortic Neck

PURPOSE

We hypothesized that extending the proximal landing zone with the chimney technique could be beneficial in patients with a hyperangulated proximal aortic neck, defined as more > 60 degrees.

MATERIAL AND METHODS

We retrospectively analyzed the outcome of prospectively collected data of patients treated by endovascular aneurysm repair (EVAR) for infrarenal aortic aneurysm with a hyperangulated proximal aortic neck. In all, 104 out of 130 patients were treated without (Group A) and 24 with the chimney endovascular aortic repair (ChEVAR, Group B). Primary outcome was technical and clinical success according to the reporting standards of the Society of Vascular Surgery.

RESULTS

The use of the chimney technique was associated with a significantly longer operation duration (167 vs. 93 min, p < .001), longer fluoroscopy time (44 vs.30 min, p = < .001), and larger amount of contrast medium used (149 vs. 127 ml, p = .03) but did not significantly improve technical (79.2% vs. 87.7%) and clinical success (54.2% vs. 68.9%). Aneurysm-related mortality was higher in group B (8.3% vs. = 0%, p < .001). Type IA endoleak was high in both groups at completion angiography (11.3% in Group A vs. 12.5% in Group B) and at follow-up (10.4% in Group A vs. 4.5% in Group B) without significant difference between the groups.

CONCLUSIONS

Our data did not show a benefit of the primary use of the chimney technique in patients with a hyperangulated and short neck, although more studies are required to support this conclusion. Other strategies or new technologies are required for improving EVAR results in aneurysm patients with severe angulated proximal and short neck.

A preliminary analysis of late structural failures of the Navion stent graft in the treatment of descending thoracic aortic aneurysms

OBJECTIVE

Patients in the Valiant Evo U.S. and international clinical trials had positive short-term outcomes; however, late structural failures, including type IIIb endoleaks have been recently discovered. Type IIIb endoleaks are serious adverse events because the repressurization of the aneurysm sac increases the risk of rupture. The purpose of the present study was to detail the imaging patterns associated with the structural failures with the aim of increasing awareness of failing graft presentation, early recognition, and prompt treatment.

METHODS

The Valiant Evo clinical trial was a prospective, single-arm investigation of a thoracic stent graft system. With the recent late structural failures, sites were requested to submit all available imaging studies to date to allow the core laboratory to assess for structural failures such as type IIIb endoleaks, stent ring fractures, and stent ring enlargement. Of the 100 patients originally enrolled in the trial from 2016 to 2018, the core laboratory assessed the imaging studies performed at ≥1 year for 83 patients.

RESULTS

No structural failures of the graft were reported through 1 year of follow-up. At 1 to 4 years, graft structural failures were detected in 11 patients with descending thoracic aortic aneurysms. Of the 11 patients, 5 had a type IIIb endoleak. Four of the five had imaging findings showing stent fractures consistent with the location of the graft seam and one had a type IIIb endoleak attributed to calcium erosion with no stent fracture or ring enlargement. Of the four patients with stent fracture in line with the graft seam, three underwent a relining procedure that successfully excluded the type IIIb endoleak. One of these three patients died 4 days later of suspected thoracic aortic rupture because the distal thoracic endovascular aortic repair extension had been landed in a previously dissected and fragile section of the aorta. The remaining six patients had had stent ring enlargement. One of the six patients had had persistent aneurysm expansion from the time of implantation onward and had died of unknown causes. The remaining five patients have continued to be monitored.

CONCLUSIONS

In the present preliminary analysis, the imaging patterns associated with type IIIb endoleaks, stent fractures, and stent ring enlargement appear to be related to the loss of seam integrity or detachment of the stent rings from the surface of the graft material. The imaging patterns we have detailed should be closely monitored using computed tomography angiography surveillance to allow structural failures to be promptly identified and treated.

Editor's Choice - Mid Term Outcomes of Crossed Limb vs. Standard Limb Configuration in Endovascular Abdominal Aortic Aneurysm Repair: A Propensity Score Analysis

OBJECTIVE

The aim was to compare mid term outcomes between crossed limb (CL) and standard limb (SL) configuration in patients who underwent endovascular aortic aneurysm repair (EVAR).

METHODS

This was a comparative cohort study. Eligible patients who underwent EVAR between September 2011 and March 2019 in a tertiary academic centre were included. Inverse probability of treatment weighting (IPTW) was used to balance the demographic, anatomical and operative baseline characteristics between the two groups. The primary outcome was adverse limb events including type IB endoleak (T1BEL), type III endoleak, and limb occlusion. Cox proportional hazards regression and marginal structural model were performed to compare time to event outcomes.

RESULTS

The study included 729 patients (194 CL and 535 SL) with a median follow up of 34 months (interquartile range 16 - 62 months). The weighted analyses revealed no significant difference between CL and SL EVAR in terms of adverse limb events, type IA endoleak (T1AEL), type II endoleak (T2EL), re-intervention, and overall survival. In the subgroup analysis of large aneurysm sac, the CL configuration was associated with a significantly decreased risk of T1BEL (hazard ratio [HR] 0.31, 95% confidence interval [CI] 0.12 - 0.78, p = .014). Similar results were also observed in the subgroup of tortuous iliac arteries (HR 0.30, 95% CI 0.11 - 0.81, p = .017). After stratification by severe neck angulation, no significant difference was found between CL and SL EVAR for T1AEL, but the CL configuration was associated with a significantly increased risk of re-intervention (HR 2.69, 95% CI 1.31 - 5.51, p = .007). In addition, a trend towards a higher risk of adverse limb events in the CL group with severely angulated proximal neck was observed.

CONCLUSION

CL configuration in EVAR is safe and may be associated with a lower risk of T1BEL in patients with a large aneurysm sac or tortuous iliac arteries. However, it should be applied cautiously to aneurysms with a severely angulated neck due to the potentially higher risk of re-intervention.

Effect of aortic angulation on the outcomes of fenestrated-branched endovascular aortic repair

OBJECTIVE

To investigate the effect of aortic angulation on the early and midterm outcomes of fenestrated-branched endovascular aneurysm repair for thoracoabdominal aortic aneurysms (TAAA) or pararenal aortic aneurysms (PRAA).

METHODS

We retrospectively reviewed the data of consecutive patients enrolled in a prospective nonrandomized physician-sponsored investigational device exemption study (2013-2018). The infrarenal, suprarenal, and supraceliac aortic angles were measured on three-dimensional reconstructions of the preoperative computed tomography angiogram; a 45° cutoff was used for the analysis. End points were technical success, freedom from endograft-related complications (defined by type IA/IB/IIIA/IIIB/IIID endoleaks, and limb thrombosis); and freedom from target vessel instability (defined by branch-related death, occlusion, rupture or reintervention for stenosis, endoleak, or disconnection). Cox proportional hazard multivariable regression analyses were preformed to assess impact of covariates.

RESULTS

There were 298 patients treated for 102 PRAAs (34%) and 196 TAAAs (66%) (78 extent IV, 118 extent I-III) with 1156 renal-mesenteric vessels incorporated. An angulation of >45° was present in the infrarenal aortic axis in 94 patients (32%), suprarenal axis in 39 (13%), and supraceliac axis in 93 (31%). A supraceliac angle of >45° was more common with extent I-III TAAAs (P = .01). Technical success was 97% and was not significantly related to aortic angulation; the total operating time and fluoroscopy time were significantly longer in patients with any aortic angulation of >45°. Freedom from endograft-related complications was 93% (95% confidence interval [CI], 90%-97%) at 42 months, and was not associated with infrarenal (HR, 1.0; 95% CI, 0.4-2.9; P = .976), suprarenal (HR, 1.7; 95% CI, 0.5-1.8; P = .428), or supraceliac (HR, 0.9; 95% CI, 0.3-2.6; P = .886) aortic angles of >45°. Overall freedom from target vessel instability was 92% (95% CI, 90%-94%) at 42 months. By multivariable analysis, target vessel instability was not affected by an infrarenal angle of >45° (HR, 1.5; 95% CI, 0.9-2.4; P = .135) and a supraceliac angle of >45° (HR, 0.9; 95% CI, 0.5-1.5; P = .627), but was associated with a suprarenal angle of >45° (HR, 5.6; 95% CI, 3.5-9.1; P < .001), even after adjustment for aneurysm extent and type of bridging stent. In this subgroup of patients, the use of directional branch vs fenestration (P = .10) and the type of bridging stent (P = .10) did not significantly impact target vessel instability.

CONCLUSIONS

Fenestrated-branched endovascular aneurysm repair can achieve excellent early and midterm results among patients with an aortic angulation of >45°, with no increase in rates of graft-related complications. However, increased aortic angulation was associated with longer operative and fluoroscopy times. The suprarenal aortic angle was the most important determinant of more target vessel events, independent of stent design or which bridging stent was selected.