Visceral stent patency after fenestrated endovascular aneurysm repair using bare-metal stent extensions versus covered stents only

Outcomes of iCAST Bridging Stents in Zenith Fenestrated Endografts - A Single Center Experience

OBJECTIVES

To evaluate outcomes of patients undergoing placement of balloon-expandable iCAST bridging stents during fenestrated endovascular aortic aneurysm repair (FEVAR) with Zenith Fenestrated Endografts (ZFEN), and to identify pre-operative and peri-operative risk factors for stent-related complications.

METHODS

Between 2012-2020, 207 patients underwent FEVAR using unmodified ZFEN with bridging iCAST covered stents to visceral target vessels. We collected patient demographics and operative variables from the index repair. We collected long term follow up data for endoleaks, branch patency, and re-intervention. We defined branch stent complications as malalignment, kinking, occlusion or endoleak requiring intervention as determined by surveillance imaging studies. We compared variables from the index operation in those patients with stent complications to those patients without stent complications to identify significant risk factors.

RESULTS

Patients in our cohort were predominantly male (n=158, 76.3%), white (n=199, 96.1%), and demonstrated cardiovascular comorbidity. The majority of repairs were for juxtarenal aortic aneurysms (n=149, 72%) with the remainder of repairs extending further cephalad. We identified 23 patients with bridging stent complications in follow up that required re-intervention. Brachial access was more frequently used in the complication group (34.8% vs 15.8%, p = 0.0251). A significantly higher proportion of patients in the complication group were treated for extent IV thoracoabdominal aneurysms (17.8% vs 5.4%, p = 0.0316). Additional patient characteristics and perioperative factors are compared between the branch complications and no branch complications groups in Table 1. An intervention-free patency Kaplan-Meier plot is presented in Figure 1.

CONCLUSIONS

Here we present a large single institution experience with iCAST branch stents during FEVAR using unmodified ZFEN and risk factors for stent related complications. Patients with branch complications were more likely to have brachial access and more extensive aneurysm repair. Most branch complications were identified within the first two years, with half of re-interventions occurring within 7.5 months of the index operation.

Physician modification of the Gore conformable endovascular aortic device using inner branches

Endovascular aortic repair has become the preferred treatment modality for patients with abdominal aortic aneurysms. However, there are no commercially available endovascular options in patients with infrarenal necks measuring <4 mm. To address the limitations of commercially available options, physician-modified endografts became a technique used by vascular surgeons. In this report, we describe a case of a patient treated with a physician-modified Gore conformable endograft using inner branches along with how to perform the procedure.

Fate of target visceral vessels in fenestrated and branched complex endovascular aortic repair

OBJECTIVE

To assess branch vessel outcomes after endovascular repair of complex aortic aneurysms analyzing possible factors influencing early and long-term results.

METHODS

The Italian Multicentre Fenestrated and Branched registry enrolled 596 consecutive patients treated with fenestrated and branched endografts for complex aortic disease from January 2008 to December 2019 by four Italian academic centers. The primary end points of the study were technical success (defined as target visceral vessel [TVV] patency and absence of bridging device-related endoleak at final intraoperative control), and freedom from TVV instability (defined as the combined results of type IC/IIIC endoleaks and patency loss) during follow-up. Secondary end points were overall survival and TVV-related reinterventions.

RESULTS

We excluded 591 patients (3 patients with a surgical debranching and 2 patients who died before completion from the study cohort) were treated for a total of 1991 visceral vessels targeted by either a directional branch or a fenestration. The overall technical success rate was 98.4%. Failure was related to the use of an off-the-shelf (OTS) device (custom-made device vs OTS, HR, 0.220; P = .007) and a preoperative TVV stenosis of >50% (HR, 12.460; P < .001). The mean follow-up time was 25.1 months (interquartile range, 3-39 months). The overall estimated survival rates were 87%, 77.4%, and 67.8% at 1, 3, and 5 years, respectively (standard error [SE], 0.015, 0.022, and 0.032). During follow-up, TVV branch instability was observed in 91 vessels (5%): 48 type IC/IIIC endoleaks (2.6%) and 43 stenoses-thromboses (2.4%). The extent of aneurysm disease (thoracoabdominal aortic aneurysm [TAAA] types I-III vs TAAA type IV/juxtarenal aortic aneurysm/pararenal aortic aneurysm) was the only independent predictor for developing a TVV-related type IC/IIIC endoleak (HR, 3.899; 95% confidence interval [CI]:, 1.924-7.900; P < .001). Risk of patency loss was independently associated with branch configuration (HR, 8.883; P < .001; 95% CI, 3.750-21.043) and renal arteries (HR, 2.848; P = .030; 95% CI, 1.108-7.319). Estimated rates at 1, 3, and 5 years of freedom from TVV instability and freedom from TVV-related reintervention were 96.6%, 93.8%, and 90% (SE, 0.005, 0.007, and 0.014) and 97.4%, 95.0%, and 91.6% (SE, 0.004, 0.007, and 0.013), respectively.

CONCLUSIONS

Intraoperative failure to bridge a TVV was associated with a preoperative TVV stenosis of >50% and the use of OTS devices. Midterm outcomes were satisfying, with an estimated 5-year freedom from TVV instability and reintervention of 90.0% and 91.6%, respectively. During follow-up, the larger extent of aneurysm disease was associated with an increased risk of TVV-related endoleaks, whereas a branch configuration and renal arteries were more prone to patency loss.

Endovascular treatment of thoracoabdominal aortic aneurysms

Endovascular repair of thoracoabdominal aneurysms using fenestrated and/or branched stent grafts is technically feasible and efficacious but carries a steep learning curve. This innovative surgical approach is associated with less perioperative morbidity than traditional open repair and its early and mid-term outcomes are very favorable. Spinal cord ischemia remains a devastating complication after these procedures, hence the importance of various neuroprotective strategies. Widespread applicability remains limited in the United States, as no custom-made or off-the-shelf endografts are commercially available. Access to these devices remains limited to physician-sponsored or industry-sponsored clinical trials, but results from the Cook p-Branch and Gore Thoracoabdominal Branch Endoprosthesis trials are on the horizon.

Evaluation of physician-modified endografts for the treatment of thoraco-abdominal and pararenal aortic pathologies at a single institution

BACKGROUND

This study aimed to describe the outcomes of high-risk patients with symptomatic or impending ruptured pararenal aneurysm and thoraco-abdominal aortic aneurysm with comorbidities unsuitable for conventional open surgery, using physician-modified endografts (PMEGs).

METHODS

A single-center retrospective analysis was conducted on 59 patients (mean age: 75 years; 47 males) treated with PMEGs between 2017 and 2020. Data on baseline characteristics, procedures, and clinical follow up were collected to retrospectively analyze early (technical success, perioperative mortality, and major adverse events) and late (patency, endoleak, intervention, aneurysm thrombosis, and survival) outcomes.

RESULTS

Technical success was achieved in 96.6% (57/59) of cases. The 30-day mortality rate was 5.1% (3/59). Five patients suffered renal failure and required temporary or permanent dialysis, one developed respiratory failure, and one suffered bowel ischemia. The major stroke rate was 3.4%, the spinal cord injury rate was 0%, and the myocardial infarction rate was 3.4%. During a mean follow-up period of 18.8 ± 9.2 months, one patient suffered upper gastrointestinal bleeding and died after 7 postoperative months. Primary branch patency was observed in 97.2% of target vessels. Estimated freedom from reintervention was 88.1% and 87.5% at 6 months and 1 year, respectively. Five cases of endoleak (one type I, one type II, and three type III) were detected, and 7.1% required reintervention. The aneurysmal lumen thrombosis rate at 1 year was 89.6%. The estimated overall survival rate was 94.9% and 92.9% at 6 and 12 months, respectively.

CONCLUSIONS

When used by experienced teams under appropriate anatomical conditions, PMEGs are a safe and effective alternative to open surgery. However, further technical advancement and larger studies with long-term follow-up periods are warranted.

Insights on Bridging Stent Grafts in Fenestrated and Branched Aortic Endografting

Major branches of the aortic arch and visceral aorta pose a particular challenge for endovascular repair of aneurysms involving these regions. To preserve perfusion through these essential branches, fenestrated and branched endografts have been used. Current fenestrated and branched aortic endografts have evolved into modular devices in which the aortic main body provides appropriate access to the target branch vessel either through reinforced fenestrations or directional cuffs as the hinge point for bridging stent grafts (BSGs). BSGs are used to connect the aortic main body and target branch vessel, and must provide both unhindered flow and a seal. Appropriate selection of BSG for target vessels in branched and fenestrated endovascular aortic repair is critical for technical success and durability. At present, there are no dedicated devices for use as BSGs, and a variety of stent grafts are currently used off-label. In this report, we review the available published series on the performance of presently available BSGs in relation to their design and selection.

Preliminary Outcomes of Viabahn Balloon-Expandable Endoprosthesis as Bridging Stent in Renal Arteries During Fenestrated Endovascular Aortic Repair

PURPOSE

To report preliminary outcomes of Viabahn Balloon-Expandable Endoprosthesis (VBX) stent-graft as bridging stent for renal arteries in fenestrated endovascular aneurysm repair (FEVAR).

MATERIALS AND METHODS

Between 2018 and 2019, patients undergoing FEVAR at 3 referral Italian university hospitals were prospectively collected. During the study period, VBX was the first-line choice as bridging stent for renal arteries. Procedural and anatomical data were analyzed, including renal artery (RA) configuration. A dedicated software (3Mensio, Vascular Imaging, Bilthoeven, The Netherlands) was used and RA anatomy classified as follow: upward-oriented in case of any angle >30° above the horizontal or transverse axis perpendicular to the aortic axis, downward-oriented if there was an angle >30° measured below the transverse axis and downward + upward in case of an angle <30° associated with a renal artery angulation >90°. Primary endpoints were technical success, defined as complete deployment of the fenestrated endograft without target vessel (TV) loss, limb stenosis or occlusion and type I or III endoleak, and freedom from target artery instability (TAI), defined by target vessel-related death, occlusion, rupture or reintervention for stenosis, endoleak or disconnection. Secondary endpoints were target artery patency rate and freedom from reinterventions.

RESULTS

A total of 26 elective FEVAR for juxta/pararenal aneurysm (20), thoracoabdominal type II (3) and type IV (3) were included. Fifty-one RA were planned for revascularization. Of these, 32 were downward, 10 horizontal, 6 upward, 4 were downward + upward. Technical success was achieved in 88.5% (23/26) of patients and 94.2% (48/51) of the TVs. One occlusion (2.1%) occurred within 30 days in a patient with previous endovascular aortic repair and suprarenal fixation. During follow-up (median 10 months), there was 1 type IC endoleak after 6 months (2.1%) in a patient with upward plus downward arterial orientation. Freedom from TAI was 96.1% (CI = 0.89 to 1.04) at first month and 92.3% (CI = 0.82 to 1.03) at 6 months. No aneurysm-related mortality and renal insufficiency occurred during follow-up.

CONCLUSION

The use of VBX as bridging stent of RA in FEVAR is safe and feasible. Previous EVAR and tortuosity of RA may be a challenging on target vessel fate.

Effects of preoperative visceral artery stenosis on target artery outcomes after fenestrated/branched endovascular aortic aneurysm repair

OBJECTIVE

Target artery stenosis might affect the outcomes of fenestrated/branched endovascular aortic aneurysm repair (F-BEVAR). The aim of the present study was to assess the effects of preoperative stenosis of the celiac artery (CA) and superior mesenteric artery (SMA) on the target artery outcomes after F-BEVAR.

METHODS

During a 4-year period, 287 consecutive patients, 204 men (71%) and 83 women (29%), had undergone F-BEVAR using fenestrated (83%), fenestrated-branched (4.5%), branched (3.5%), and off-the-shelf t-Branch (9%) devices (Cook Medical Inc, Bloomington, Ind). Preoperative SMA and CA significant stenosis was defined as a computed tomography angiography-based intraluminal diameter reduction >50%. The primary endpoints included primary patency, freedom from target vessel instability, and patient survival.

RESULTS

The median patient age was 71 years (interquartile range, 67-77 years). Suprarenal (36%), juxtarenal (25%), and thoracoabdominal (39%) aortic aneurysms were treated. The technical success rate was 99%. The 30-day survival was 97%. Among 981 stented vessels, 179 (18%) were CAs and 270 (27.5%) were SMAs. Significant preoperative CA stenosis was identified in 39 patients (22%) and SMA stenosis in 24 (9%). The median follow-up was 29.9 months. The primary patency rates at 12, 36, and 60 months were 98%, 92%, and 92% for the CA and 99%, 98%, and 98% for the SMA, respectively. Primary patency was significantly lower in the patients with previous significant CA stenosis than in those without stenosis (83%, 83%, and 76% vs 100%, 100%, and 97% at 12, 36, and 60 months, respectively; P < .01). Freedom from celiac branch instability was also significantly lower among patients with significant stenosis (84%, 84%, and 76% vs 100%, 93%, and 93% at 12, 36, and 60 months; P < .01). The presence of significant SMA stenosis did not affect either primary patency or freedom from target vessel instability. The survival rates at 12, 36, and 60 months were significantly lower for the patients with CA stenosis than for those without stenosis (67%, 61%, and 55% vs 90%, 84%, and 82%, respectively; P < .01). Similarly, lower survival rates were observed for patients with significant SMA stenosis (70%, 60%, and 60% vs 87%, 79%, and 78% at 12, 36, and 60 months, respectively; P = .04).

CONCLUSIONS

F-BEVAR was associated with overall primary patency rates >90% for the CA and SMA. Preoperative CA stenosis was associated with lower primary patency and freedom from target vessel instability. In contrast, neither SMA branch primary patency nor freedom from target vessel instability were affected by preoperative SMA stenosis. We found visceral artery stenosis was a marker of atherosclerosis burden associated with reduced mid- and long-term patient survival.

Comparison of the Biomechanical Properties of the Advanta V12/iCast and Viabahn Stent-Grafts as Bridging Devices in Fenestrated Endografts: An In Vitro Study

Purpose: To compare experimentally the biomechanical properties of the Viabahn Balloon-Expandable Stent Graft (VBX) with the widely used Advanta V12/iCast in the role of bridging stent-grafts for fenestrated endovascular aortic repair. Materials and Methods: Test sheets made of polyester having 2 rows of 5 fenestrations in 6-mm and 8-mm diameters were used to simulate a commercially made fenestrated aortic endograft. In total, 40 stent-grafts measuring 6×39 mm and 8×39 mm (10 of each size for each stent-graft) were implanted in fenestration sheets immersed in a 37°C water bath. After flaring, all stent-grafts were evaluated using microscopy and radiography. Biomechanical evaluation included pullout and the shear stress force testing; results are reported in Newtons (N) as the median (minimum–maximum). Results: After flaring, no damage or fracture to the stent-graft structures were detected. Pullout forces for the 6-mm stent-grafts were 27.1 N (20.0–28.9) for the VBX and 16.6 N (14.7–19.2) for the Advanta (p=0.008). Pullout forces for the 8-mm stent-grafts were 20.1 N (14.8–21.5) for the VBX and 15.8 N (12.4–17.5) for the Advanta (p=0.095). The shear stress forces necessary to dislocate the device at 150% stent diameter displacement was 12.5 N (VBX) vs 14.7 N (Advanta) for the 6-mm devices and 23.3 N (VBX) vs 20.2 N (Advanta) for the 8-mm stents (p>0.99 and p=0.222, respectively). Conclusion: In vitro tests simulating external pull and shear forces on bridging stent-grafts implanted in fenestrations showed that the VBX had resistance to dislocation equivalent to a well-known control device.