The Impact of Target Vessel Anatomy and Bridging Stent Geometry on Branched Endovascular Aortic Repair Outcomes

OBJECTIVE

This study aimed to evaluate the impact of target vessel anatomy and bridging stent geometry on target vessel instability in branched endovascular aortic repair (b-EVAR).

METHODS

This retrospective, single centre cohort study included all consecutive b-EVARs performed between September 2018 and December 2022 for thoracoabdominal (TAAA) or complex abdominal aortic aneurysms (CAAA). The primary endpoints were target vessel instability and related re-interventions at 12 months. Secondary endpoints were 30 day results, including target vessel instability and re-interventions. Target vessel instability analysis consisted of assessment of target vessel anatomy, including diameter, aortic trunk to branch angle, and tortuosity. Post-operative parameters included change of clock position/horizontal misalignment, bridging length (gap), sealing length, tortuosity, post-stenting angle, and oversizing ratio.

RESULTS

A total of 69 patients (TAAA: n = 56, 81%; CAAA: n = 13, 19%) and 271 (133 visceral and 138 renal) target vessels were included. Cumulative incidence of target vessel instability was 4.8%, 6.4%, and 7.9% at one year, two years, and three years, respectively. In the renal target vessel group, vessel diameter ≤ 4 mm (hazard ratio [HR] 1.28, 95% confidence interval [CI] 1.116 - 2.54; p = .022) and a bridging length ≥ 25 mm (HR 1.320, 95% CI 1.066 - 1.636; p = .011) were associated to increased target vessel instability. In visceral vessels, a change in clock position/horizontal misalignment ≥ 70 minutes (HR 1.072, 95% CI 1.026 - 1.121; p = .002) showed a significant association with target vessel instability.

CONCLUSION

Target vessel diameter, bridging length (gap), and horizontal misalignment seemed to be associated with adverse target vessel outcomes. This may be solved with more customised endograft solutions to reduce the negative impact of the latter parameter.

Five-year outcomes of fenestrated and branched endovascular repair of complex aortic aneurysms based on aneurysm extent

OBJECTIVE

The aim of this study was to evaluate the 5-year outcomes of fenestrated/branched endovascular aortic repair (F/BEVAR) for the treatment of complex aortic aneurysms stratified by the aneurysm extent.

METHODS

Patients with the diagnosis of complex aortic aneurysm, who underwent F/BEVAR at a single center were included in this study and retrospectively analyzed. The cohort was divided according to the aneurysm extent, comparing group 1 (types I-III thoracoabdominal aneurysms [TAAAs]), group 2 (type IV TAAAs), and group 3 (juxtarenal [JRAAs], pararenal [PRAAs], or paravisceral [PVAAs] aortic aneurysms). The primary endpoints were 30-day and 5-year survival. The secondary endpoints were technical success, occurrence of spinal cord ischemia, primary patency of the visceral arteries, freedom from target vessel instability, and secondary interventions.

RESULTS

Of 436 patients who underwent F/BEVAR between July 2012 and May 2023, 131 presented with types I to III TAAAs, 69 with type IV TAAAs, and 236 with JRAAs, PRAAs, or PVAAs. All cases were treated under a physician-sponsored investigational device exemption protocol with a patient-specific company-manufactured or off-the-shelf device. Group 1 had significantly younger patients than group 2 or 3 respectively (69.6 ± 8.7 vs 72.4 ± 7.1 vs 73.2 ± 7.3 years; P < .001) and had a higher percentage of females (50.4% vs 21.7% vs 17.8%; P < .001). Prior history of aortic dissection was significantly more common among patients in group 1 (26% vs 1.4% vs 0.9%; P < .001), and mean aneurysm diameter was larger in group 1 (64.5 vs 60.7 vs 63.2 mm; P = .033). Comorbidities were similar between groups, except for coronary artery disease (P < .001) and tobacco use (P = .003), which were less prevalent in group 1. Technical success was similar in the three groups (98.5% vs 98.6% vs 98.7%; P > .99). The 30-day mortality was 4.5%, 1.4%, and 0.4%, in groups 1, 2, and 3, respectively, and was significantly higher in group 1 when compared with group 3 (P = .01). The incidence of spinal cord ischemia was significantly higher in group 1 compared with group 3 (5.3% vs 4.3% vs 0.4%; P = .004). The 5-year survival was significantly higher in group 3 when compared with group 1 (P = .01). Freedom from secondary intervention was significantly higher in group 3 when compared with group 1 (P = .003). At 5 years, there was no significant difference in freedom from target vessel instability between groups or primary patency in the 1652 target vessels examined.

CONCLUSIONS

Larger aneurysm extent was associated with lower 5-year survival, higher 30-day mortality, incidence of secondary interventions, and spinal cord ischemia. The prevalence of secondary interventions in all groups makes meticulous follow-up paramount in patients with complex aortic aneurysm treated with F/BEVAR.

Effect of narrow paravisceral aorta on target vessel instability after fenestrated and branched endovascular aortic repair

OBJECTIVE

To investigate the effect of narrow paravisceral aorta (NPA) on target vessel instability (TVI) after fenestrated-branched endovascular aortic repair.

METHODS

We conducted a single-center retrospective study (2014-2023) of patients treated by fenestrated-branched endovascular aortic repair for thoracoabdominal aortic aneurysms (TAAA) or pararenal aortic aneurysms. The paravisceral aorta was defined as the aortic segment limited by the diaphragmatic hiatus proximally and the emergence of lower renal artery distally, and was considered "narrow" in case of a minimum inner diameter of <25 mm. The minimum aortic diameter, location, longitudinal extension, angulation, calcification, and thrombus thickness of NPA were evaluated at the preoperative computed tomography angiogram. End points were 30-day technical success and freedom from TVI.

RESULTS

There were 142 patients with JRAA/pararenal aortic aneurysm (n = 85 [59%]) and extent IV (n = 24 [17%]) or extent I-III (n = 33 [23%]) TAAA, with 513 target arteries successfully incorporated through a fenestration (n = 294 [57%]) or directional branch (n = 219 [43%]). A NPA was present in 95 patients (70%), 73 (86%) treated by fenestrated endovascular aortic repair (FEVAR) and 22 (39%) by branched endovascular aortic repair (BEVAR). The overall 30-day mortality was 2% and technical success was 99%, without differences between NPA and non-NPA (P = .99). Kaplan-Meier estimated freedom from TVI at 4 years was 82%, 81% (95% CI, 75-95) in patients with a NPA and 80% (95% CI, 68-94) and in those without NPA (P = .220). The result was maintained for both FEVAR (NPA: 81% [95% CI, 62-88]; non-NPA: 76% [95% CI, 60-99]; P = .870) and BEVAR (NPA: 77% [95% CI, 69-99]; non-NPA: 80% [95% confidence interval (CI) 66-99]; P = .100). After multivariate analysis, the concomitant presence of a NPA <20 mm and angulation of >30° was significantly associated with TVI in FEVAR (HR, 3.21; 95% CI, 1.03-48.70; P = .036), being the result mostly driven by target vessel occlusion. In BEVAR, a NPA diameter of <25 mm was not associated with TVI (HR, 2.02; 95% CI, 0.59-5.23; P = .948); after multivariate analysis, the use of outer branches in case of a NPA longitudinal extension of >25 mm (hazard ratio [HR], 3.02; 95% CI, 1.01-36.33; P = .040) and NPA severe calcification (HR, 1.70; 95% CI, 1.00-22.42; P = .048) were associated with a higher chance for TVI.

CONCLUSIONS

FEVAR and BEVAR are both feasible in cases of NPA and provide satisfactory target vessels durability. The use of outer branches should be avoided in cases with an inner aortic diameter of <25 mm with a longitudinal extension of >25 mm or moderate to severe NPA calcifications. In FEVAR, bridging stent patency may be negatively influenced by NPA of <20 mm in association with aortic angulation of >30°.

Analysis of predisposing factors for type III endoleaks from directional branches after branched endovascular repair for thoracoabdominal aortic aneurysms

BACKGROUND

Mid-term durability of branches has already been established, and BF-branched and fenestrated endovascular repair has shown comparable results with open repair in the treatment of thoracoabdominal aortic aneurysms (TAAAs). Nevertheless, target vessel instability remains the most frequent adverse event after complex endovascular aortic repair. Type III endoleaks from directional branches have been reported with a low incidence, but risk factors for this complication have not been investigated yet.

METHODS

This was a dual-center observational retrospective cohort study. Data were collected prospectively for each patient treated with branched endovascular repair between April 2008 and December 2019. The primary outcome was to assess potential risk factors for branch disconnection and fracture. A logistic regression analysis was performed, including preoperative and postoperative measurements as well as intraoperative details. A Cox regression hazard analysis was performed to evaluate the influence of preoperative aneurysm diameter and target vessel angulation on the outcome during follow-up.

RESULTS

Two hundred ninety-five target visceral vessels (TVVs) in 91 patients were considered suitable for cannulation. Technical success was 96.9% (286/295 TVVs). The median follow-up was 32.5 months (interquartile range, 14.2-50.1 months). Twelve type III endoleaks from directional branches were detected (4.2%; 5 bridging stent graft fractures and 7 disconnections). Five type III endoleaks involved the celiac trunk (one fracture and four disconnections), five the superior mesenteric artery (four fractures and one disconnection), and two the renal arteries (both disconnections). The median time to type III endoleak was 22.2 months (interquartile range, 10.9-37.6 months). Preoperative TAAA diameter (P = .028), preoperative TVV angulation (P = .037), the use of a BeGraft stent graft as bridging stent graft (P = .001), and different stent types on the same vessel (P = .048) were associated with type III endoleak at univariable analysis. Using a BeGraft stent graft (P = .010) was the only significant factor predisposing to type III endoleak at multiple logistic regression. The Cox regression analysis showed a two-fold increased risk for type III endoleak for every 10-mm increase in preoperative TAAA diameter (hazard ratio, 2.00; 95% confidence interval, 1.08-3.72; P = .028) and a 1.5 increased risk every 12° increase of preoperative TVV angulation (hazard ratio, 1.47; 95% confidence interval, 1.02-2.10; P = .037).

CONCLUSIONS

Type III endoleaks from directional branches are a non-negligible complication after branched endovascular repair, with a relevant incidence. They tended to be clustered on specific patients, and aneurysm diameter and TVV angulation are strictly associated with the outcome. Different stent types on the same vessel should be avoided whenever possible. An intensified follow-up should be adopted for patients with large aneurysms, implanted with first-generation BeGraft, or who have been already diagnosed with type III endoleaks.

Bridging stent-graft fracture after branched endovascular aortic repair in a dual-center retrospective cohort study

OBJECTIVE

Target vessel instability is a relevant complication after thoracoabdominal aortic aneurysms branched endovascular aortic repair (BEVAR). Long-term bridging stent-graft (BSG) durability has already been established, but the incidence of long-term complications as component fractures was not deeply investigated. This paper aims to assess BSG fracture incidence and risk factors after BEVAR.

METHODS

This was a dual-center observational retrospective cohort study. Data of each patient treated with BEVAR between April 2008 and December 2019 were prospectively collected. The primary outcome was the incidence of BSG fracture during follow-up. A logistic regression analysis was performed, including preoperative and postoperative measurements as well as intraoperative details to identify potential risk factors.

RESULTS

Two hundred ninety-five target visceral vessels in 91 patients were considered suitable for cannulation. Technical success was 96.9% (286/295 target visceral vessels). The median follow-up was 32.5 months (interquartile range, 14.3-50.1 months). Five BSG fractures (1.75%; 5/286) were detected. Four BSG fractures involved the superior mesenteric artery, and one the celiac trunk. Four different types of fractured stents were detected during follow-up: two Advanta, one BeGraft, one Fluency, and one Viabahn. The median time to BSG fracture was 28.2 months (interquartile range, 11.7-50.8 months). The use of multiple stents (P = .030) and different stent types on the same vessel (P = .004) were associated with BSG fracture at univariable analysis. Using bare-metal stents for distal relining (P = .045) was the only significant factor predisposing to BSG fracture at multiple logistic regression.

CONCLUSIONS

BSG fracture is a rare but severe complication after BEVAR. It is not related to the stent type used as bridging stent, and it is hardly predictable based on preoperative anatomy. Using multiple and different stents on the same vessel and relining the bridging stents with bare-metal stents may increase BSG fracture risk. A strict computed tomography angiography follow-up remains the best strategy to detect target vessel instability.