Two Decades of Abdominal Aortic Endovascular Repair With the Anatomical FiXation at the Aortic Bifurcation in a Large Single-Center Experience

Tailoring silk-based covering material with matched mechanical properties for vascular tissue engineering

Vascular covered stents play a significant therapeutic role in cardiovascular diseases. However, the poor compliance and biological inertness of commercial materials cause post-implantation complications. Silk fibroin (SF), as a biomaterial, possesses satisfactory hemocompatibility and tissue compatibility. In this study, we developed a silk film for use in covered stents by employing a layer-by-layer self-assembly strategy with regenerated SF on silk braiding fabric. We investigated the effects on the mechanical properties of the silk films in detail, which were closely correlated with fabric parameters and layer-by-layer self-assembly. The results showed that there was a significant relationship between these factors and both the compliance and mechanical strength. The 1 × 2/90°/100/SF6 film exhibited excellent mechanical properties. Notably, compliance reached 2.6%/100 mmHg, matching that of the human saphenous vein. Thus, this strategy shows promise in developing a novel covered stent, with biocompatible and comprehensive mechanical properties, and significant potential for clinical applications.

Infrarenal Aortic Treatment With AFX2 Endograft: Results From a Multicentric, International, Non-Randomized, Prospective Registry-the AFX2-LIVE Study

INTRODUCTION

To confirm real-world clinical practice results reported with anatomically fixed bifurcated endograft, a physician-initiated study was designed-AFX2-LIVE registry.

MATERIALS AND METHODS

From November 2019 to August 2021, investigators enrolled all consecutive patients treated with AFX2 (Endologix Inc., Irvine, CA, USA) endograft. Patients with abdominal aortic aneurysms (AAAs), penetrating aortic ulcers (PAU), and isolated infrarenal aortic dissections were included. Clinical and anatomical data, including baseline, intraoperative, and in-hospital details, as well as follow-up data, were collected in an anonymized prospectively compiled database. The primary endpoint of this study was to evaluate the technical and clinical success of endovascular aortic repair (EVAR) using AFX2 endograft.

RESULTS

A total of 535 patients were enrolled from 43 Italian and Spanish centers and analyzed according to the protocol. Four hundred eighty-nine patients were male (91.4%), with a mean age of 75±8.92 years (range 52-94). Four hundred sixty-six patients (87.1%) were treated for AAA, 49 (9.3%) for PAU, and 20 (3.6%) for isolated abdominal aortic dissection. A proximal extension was needed in 48% of the cases. Assisted technical success was achieved in all but one patient (99.8%). At 30 days follow-up, no AAA-related deaths were recorded, and nine patients (1.6%) required reintervention. At a mean follow-up period of 15.22±13.65 (range 1-53) months, data were available for 479 patients (89.5%). Clinical success was achieved in 98.2% (95% confidence interval [CI]: 96.4-99.1) at 3 months, 93.9% (95% CI: 90.1-96.1) at 1 year, and 74.1% (95% CI: 62.8-82.4) at 4 years follow-up. The estimated freedom from all-cause mortality was 97.7%, 93.4%, 81.6%, 77.5%, and 70.9%, and freedom from AAA-related mortality was 100%, 99.6%, 99.6%, 99.6%, and 97.3% at 3, 12, 24, 36, and 48 months, respectively. Twenty reinterventions (3.7%) were required in 19 patients, of which 3 late open conversions (0.6%) were performed, and 2 AAA-related deaths were observed.

CONCLUSION

This study demonstrated excellent clinical and technical success rates of EVAR with anatomically fixed endografts, providing valuable insights into real-world clinical outcomes.

CLINICAL IMPACT

The AFX2-LIVE study could have a significant impact by providing robust evidence supporting the effectiveness and safety of EVAR using bifurcated endografts with anatomical fixation in real-world clinical practice, ultimately leading to improved outcomes and enhanced patient care in the management of abdominal aortic pathologies.

Type III Endoleak Incidence and Outcomes in Endovascular Aortic Repair: Comparison of Anatomical and Proximal Fixation Devices

PURPOSE

To evaluate the influence of endograft fixation type on the incidence, treatment, and outcomes of type III endoleaks (TIIIELs).

MATERIALS AND METHODS

Abdominal aortic aneurysms (AAAs) treated with bifurcated endografts between 1994 and 2020 were prospectively collected and reviewed. The endograft included were classified as "Anatomical Fixation" (AF) (Powerlink [Endologix] and AFX [Endologix]) or "Proximal Fixation" (PF). The primary outcome was the incidence of TIIIEL over time, stratified by fixation type. Secondary outcomes included between-group comparisons of baseline characteristics, intraoperative details during TIIIEL correction, and survival analysis after TIIIEL diagnosis.

RESULTS

A total of 2065 endovascular aneurysm repairs were performed: 872 (42.2%) with AF and 1193 (57.8%) with PF devices. The estimated incidence of TIIIEL at 1, 5, and 10 years was 0.4%, 4.2%, and 7.3%, and 0.5%, 3.2%, and 4.6% for AF and PF, respectively (p=0.157), and fixation type was not associated with TIIIEL development in the competing risk regression model (p=0.101). The cumulative overall survival rate in patients diagnosed with TIIIEL did not differ significantly between the groups (p=0.077). The rate of recurrent TIIIELs was significantly lower in the AF group (7.1% vs 22.7%; p=0.044); however, no significant difference was found in secondary reintervention between the two groups (11.9% vs 27.3%, p=0.074). Patients with angulated and calcified aortic neck (SHR 3.4, 95% CI 1.2-9.6, p=0.022) and larger aneurysms (SHR 1.2; 95% CI 1.1-1.3; p<0.001) had a higher risk of TIIIEL. Likewise, the use of three or more endograft components increased the risk of TIIIEL by 3.1 times (SHR 3.1; 95% CI 1.7-5.4; p<0.001).

CONCLUSIONS

The occurrence of TIIIELs was not affected by the type of endograft fixation. For larger abdominal aortic aneurysms (AAAs) and aneurysms with angulated and calcified aortic necks, there is a higher likelihood of developing TIIIELs during follow-up, regardless of the endograft type used.

CLINICAL IMPACT

The type of fixation does not influence the incidence of TIII ELs. EVAR in larger AAAs and aneurysms with angulated and calcified aortic necks have a higher risk of developing TIII EL. Moreover, the risk of TIII EL is considerably increased by the use of three or more modular components.

Incidence, Risk Factors, and Prognostic Impact of Type Ib Endoleak Following Endovascular Repair for Abdominal Aortic Aneurysm: Scoping Review

OBJECTIVE

The primary objectives of this scoping review were to assess the rate of and risk factors for type Ib endoleak and to evaluate the extent of the evidence base that links type Ib endoleak to short and long term outcomes in patients undergoing endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA).

METHODS

Potentially eligible studies were searched in the Cochrane Central Register of Controlled Trials, MEDLINE, Web of Science Core Collection, SciELO Citation Index, Russian Science Citation Index, and KCI-Korean Journal Database. A scoping review was performed according to PRISMA extension for Scoping Reviews.

RESULTS

A total of 27 articles (four prospective registries and 23 retrospective cohort studies) dealing with type Ib endoleak were included in the final analysis. The number of patients reported on was 7 197, with follow up ranging between 12 months and 93 months. The reported frequency of type Ib endoleak in patients treated with EVAR ranged from 0% to 8%, Patient and or procedure related factors associated with risk of type Ib endoleak were (1) common iliac artery (CIA) diameter ˃ 18 mm requiring use of flared stent graft limbs (FLs) ˃ 20 mm, (2) length of CIA landing zone ˂ 20 mm, (3) marked iliac tortuosity, and (4) large initial AAA diameter. Depending on the study, 50 - 100% of type Ib endoleaks were corrected by endovascular means, with a reported immediate technical success of 100% in the studies providing this information.

CONCLUSION

Type Ib endoleak after EVAR has been reported to occur in 0 - 8% of cases. Several anatomical features, including CIA diameter ˃ 18 mm or requiring the use of FLs ˃ 20 mm, length of CIA landing zone ˂ 20 mm, marked iliac tortuosity, and large initial AAA diameter, could increase the risk of type Ib endoleak and may require alternative therapeutic options and or more stringent follow up. Therefore, this updated scoping review provides a comprehensive summary of the frequency, risk factors, prognosis, and treatment of type Ib endoleaks, and has identified knowledge gaps in the literature to guide further studies.

Incidence, Long Term Clinical Outcomes, and Risk Factor Analysis of Type III Endoleaks Following Endovascular Repair of Abdominal Aortic Aneurysm

OBJECTIVE

To assess the real world incidence, outcomes, and risk factors of type III endoleaks (TIIIEL) after endovascular aneurysm repair (EVAR).

METHODS

This was a single centre, retrospective, observational, cohort study. All patients with abdominal aortic aneurysms (AAAs) receiving EVAR between 1994 and 2020 were collected prospectively and reviewed. The primary outcome was the cumulative incidence and impact on survival of TIIIELs, either defined as disconnections of modular graft components (TIIIaEL) or fabric defects (TIIIbEL). Secondary outcomes included risk factor analysis evaluating baseline morphological and stent graft details, as well as a comparison of TIIIaEL and TIIIbEL.

RESULTS

In total, 2 565 EVARs were performed and 95 (3.7%) TIIIELs were diagnosed at a median interval of 49.5 months (interquartile range [IQR] 19.4, 67.6). Estimated TIIIEL incidence at five years was 6.8%, 2.2%, and 3.6% for first and second generation, third and fourth generation, and fifth and sixth generation, respectively. The survival rate in patients without any high flow endoleak was 88.0%, 67.9%, 56.9%, and 52.1%, while in TIIIEL patients it was 98.6%, 77.2%, 49.8%, and 32.3% at one, five, 10, and 15 years, respectively (p = .77). The distribution of TIIIaEL and TIIIbEL was 70.5% and 29.5%, respectively. TIIIbEL received a higher rate of open treatment (28.6% vs. 7.5%; p = .005) and device or procedure related re-interventions (35.7% vs. 13.4%; p = .013). Fourteen (15.4%) recurrent TIIIELs were diagnosed at a median of 16.8 months (IQR 7.6, 32.1). Old generation endografts (hazard ratio [HR] 2.1, 95% confidence interval [CI] 1.3 - 3.4; p = .002) and non-proprietary extensions (HR 3.6, 95% CI 1.9 - 6.8; p < .001), and angulated and calcified aneurysm neck (HR 3.6, 95% CI 1.2 - 10.6; p = .017) were risk factors for TIIIEL. Every 10 mm maximum AAA diameter increase presented a 1.4 fold higher risk of TIIIEL.

CONCLUSION

TIIIEL is a severe condition that is often fatal if left untreated. Old endografts, the implantation of non-proprietary extensions, large AAAs, and angulated and calcified necks are risk factors for TIIIEL that require careful follow up due to the high rate of recurrence.

Anatomical Feasibility of an Off-the-shelf Single-Renal Scalloped Stent-Graft for Hostile Neck Abdominal Aortic Aneurysm: A Preclinical Study

OBJECTIVES

To evaluate the feasibility of a standardized single-renal scallop stent-graft.

DESIGN

Preclinical, single-center, real-world, all-comers, retrospective cohort study.

METHODS

A total of 1347 abdominal aortic aneurysm (AAA) repairs (endovascular and open) performed between 2010 and 2020 were screened for elective treatment and retrievable preoperative high-quality computed tomography angiography (CTA) performed <6 months of the surgical procedure. Six hundred of the included CTAs involved prespecified measurements and a morphological assessment protocol (NCT05150873). The proximal sealing zones suitable for standard stent-graft implantations were further analyzed (N=547). The primary outcome assessed the feasibility of 2 single-renal scallop designs (10×10 mm and 15×10 mm, height × width). The feasibility was the inter-renal length ≥10 mm and ≥15 mm for prototypes #10 and #15, respectively. The secondary outcome quantified hypothetical length and surface improvements comparing those suitable for investigational devices implantation (study group) versus those not (control group).

RESULTS

Of the total, 24.7% (n=135) was feasible with prototype #10. The study versus control group sealing zones were shorter (p=0.008), with a smaller surface (p=0.009) and a higher alpha angle (p=0.039). The length and surface area increased by about 25% and 23%, respectively, (both p<0.001) within the study group and became significantly better versus the control group (standard stent-graft; both p<0.001). Of the total, 7.1% (n=39) was suitable for prototype #15. The study versus control group sealing zones were shorter (p=0.148), with a smaller surface (p=0.077) and a higher alpha angle (p=0.027). The length and surface area increased by about 34% and 31%, respectively, (both p<0.001) within the study group and became significantly higher versus the control group (standard stent-graft; both p<0.001).

CONCLUSIONS

The use of single-renal scalloped stent-graft might be feasible in a considerable number of AAA patients. The breakthrough stands in treating hostile AAAs presenting in mismatched renal arteries, keeping the complexity of the repair as similar as possible to standard endovascular repair with a remarkable improvement in sealing.

CLINICAL IMPACT

The anatomic feasibility of a single renal stent graft for the treatment of "hostile" abdominal aortic aneurysm (AAA) with mismatched renal arteries was evaluated. The experimental device could be feasible in a considerable number of patients with AAA, approaching 25%, and demonstrate significant improvements in sealing. As far as we know, this is the first paper to report the prevalence of mismatched renal arteries in a large cohort of AAA patients in the real world, while proposing a dedicated device. The breakthrough is to keep the complexity of the repair as close as possible to standard endovascular repair.