Unibody Endografts for Abdominal Aortic Aneurysm Repair Reduce Radiation and Nephrotoxic Exposure Compared with Modular Endografts

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.

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.

Comprehensive Learning Curve Analysis of a Long-Term Experience With Thoracic Endovascular Aneurysm Repair

PURPOSE

To analyze the learning curve for thoracic endovascular aortic repair (TEVAR) in a single center over a period of 25 years.

MATERIALS AND METHODS

In total, 390 consecutive standard TEVAR procedures undertaken between 1996 and 2021 were included in a retrospective, observational, single-center study. Cumulative sum charts were elaborated for the entire center experience (primary outcome) as well as for the first and second implanting physicians. Data on procedural variables (contrast volume, operative and fluoroscopy time), 30-day major adverse events (MAEs) and clinical success, and endoleak and reintervention rates were secondary outcomes and subdivided into 4 quartiles of experience (Q1-Q4) or presented as first 2 versus latest 2 quartiles (Q1-Q2 vs Q3-Q4).

RESULTS

The mean follow-up was 4.3±4.0 years. The center's learning curve was achieved after 75 procedures, and it was similar for the first implanting physician. The surgeon coming thereafter had a significantly shorter curve (10 TEVARs). Comparing Q1-Q2 with Q3-Q4, 30-day MAEs (16.1 vs 11.3%, p=0.164), 30-day mortality (11.4% vs 3.6%, p=0.003), and intraoperative additional maneuvers (21.5% vs 13.3%, p=0.033) were reduced along with an improvement in clinical success (85.9% vs 90.3%, p=0.190). From Q1 to Q4, operative time (139.8±65.5 to 76.7±43.7 min, p=0.001), fluoroscopy time (15.1±8.8 to 7.1±5.1 min, p<0.001), and contrast volume (244.0±112.1 to 104.3±46.1 mL, p<0.001) showed a considerable reduction. Late endoleak and aortic-related mortality declined significantly from Q1-Q2 to Q3-Q4 (24.1% to 15.5%, p=0.033 and 18.6% vs 8.2%, p=0.006, respectively). Operative time (p=0.021), contrast volume (p=0.016), and fluoroscopy time (p=0.004) were independent risk factors for endoleak, causing a 1.3-fold risk increase for both each 60 minutes of additional operative time (p=0.021) and every 100 mL of additional contrast medium (p=0.016). Each 10-minute increase in fluoroscopy time determined a 1.4-fold risk increment (p=0.004).

CONCLUSION

The learning curve shortened significantly over time with non-negligible clinical outcome improvements, suggesting that specific endovascular training is mandatory to become an effective TEVAR performer.

CLINICAL IMPACT

For the first time in literature, the standard TEVAR's learning curve has been evaluated at a single vascular surgery center over a period of 25 years. The learning curve for the center and the first physician historically undertaking TEVAR was achieved at the 75th treated patient. The learning curve of the surgeons coming thereafter was significantly shorter (10 cases). This quarter-century demonstrated that intraoperative learning-related variables were associated with long-term clinical outcomes and all have improved over time. Centers approaching TEVAR for the first time and training program providers could use these data to aim to offer better clinical outcomes.

Learning Curve and Long-Term Outcomes of Thoracic Endovascular Repair With the Relay Stent-Graft

PURPOSE

To define the learning curve of a widely employed stent-graft for thoracic endovascular repair (TEVAR) by analyzing procedural variables and their impact on long-term outcomes.

MATERIALS AND METHODS

Standard TEVARs for each major aortic thoracic disease were included excluding procedures using thoracoabdominal, arch fenestrated/branched devices and/or chimneys. The primary outcome was the learning curve analysis using the cumulative sum chart method. The secondary outcomes, presented as early (Q1-Q2) versus latest (Q3-Q4) quartiles of experience, were 30-day major adverse events (MAEs); procedural details (additional maneuvers, operative and fluoroscopy time, and contrast volume); 30-day clinical success; endoleak; aorta-related reintervention; and overall and aorta-related survival.

RESULTS

Between November 2005 and September 2021, 220 consecutive TEVAR procedures involving the Relay endograft (Terumo Aortic, Sunrise, FL, USA) were performed and included in the present analysis. The mean follow-up was 4.5 ± 3.9 years. The learning curve was reached after 10 patients. Secondary outcomes improved significantly over experience. Thirty-day MAE occurrence was 14.5% versus 11.8% (p=0.550). Additional maneuvers (p=0.009), access-vessel additional maneuvers (p=0.010), operative time (p=0.004), Relay Plus (p=0.001), and implantation of multiple stent-grafts (p=0.034) were independent risk markers for MAEs. Operative time (125.9 ± 66.7 vs 86.7 ± 48.5 minutes, p<0.001), contrast volume (185.4 ± 112.8 vs 140.5 ± 88.2 mL, p=0.003), and fluoroscopy time (12.4 ± 12.7 vs 8.8 ± 7.5 minutes, p=0.017) decreased significantly. Late endoleak occurrence was 19.5% with a nonsignificant reduction (21.8% vs 17.3%, p=0.395). Fluoroscopy time (hazard ratio [HR]=1.0; 95% confidence interval [CI]=1.0-1.1; p=0.008), contrast volume (HR=1.0; 95% CI=1.0-1.1; p=0.018), and type III aortic arch (HR=3.3; 95% CI=1.7-6.4; p<0.001) were independent risk markers for endoleak. Fluoroscopy time (HR=1.0; 95% CI=1.0-1.1; p=0.032) and type III aortic arch (HR=3.6; 95% CI=1.7-7.4; p=0.001) confirmed their significant association in a multivariable analysis.

CONCLUSION

In a high-volume center with a consistent previous endovascular experience, the Relay graft presented satisfactory long-term results with a short learning curve supporting its reliability.

CLINICAL IMPACT

The manuscript addresses the understanding of how many TEVAR procedures with a currently implanted device have been required to reach the learning curve for an endovascular skilled center. Our TEVAR experience with the Relay stent-graft (Terumo Aortic) demonstrated that ten implantations were required to achieve the device-related learning curve. The fifteen-year analyzed period showed that intraoperative learning-related variables were associated with long-term clinical outcomes and both improved over time. The Relay stent-graft presented satisfactory long-term results along with a short learning curve in a high-volume endovascular center supporting its ongoing implantation.

Combined AFX2 with thoracic stent graft: A different endovascular approach of an abdominal aorta aneurysm

The AFX2 endovascular repair system is a unibody, bifurcated stent graft that can be used in an abdominal aortic aneurysm associated with anatomical challenges, especially if it is combined with different aortic cuffs. The use of an AFX2 main body combined with a thoracic stent graft as a proximal aortic cuff was selected to treat a 77-year-old male patient with abdominal aortic aneurysm. The AFX2 endograft combined with a proximal thoracic aortic cuff plays a safe and effective role in treating complex infrarenal abdominal aortic aneurysm that may otherwise be technically more challenging with the open technique and inaccessible with the traditional endovascular technique.

Unibody bifurcated aortic endograft: device description, review of the literature and future perspectives

The unibody (Powerlink/AFX/AFX2) Endovascular AAA device (Endologix Inc., CA, USA) presents a unique design with its long main body and two innate limbs. The device is designed to be deployed and sits on the native aortoiliac bifurcation and represents the only one-piece bifurcated endograft designed to use anatomical fixation for endograft stabilization. According to published literature, the unibody device seems to represent a valid choice in the treatment of abdominal aortic aneurysms. This particular device would seem to satisfactorily perform even in the treatment of more compressed aneurysms (also in off-label association with parallel grafts) and in occlusive pathologies. Ongoing studies will provide new real-life data in a large and unselected patient population to better understand the device’s advantages and limitations.

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

OBJECTIVE

The introduction of new endograft models improved long-term results of abdominal aortic aneurysm (AAA) endovascular repair (EVAR), but most of them maintained an old and unchanged design: a short body and long legs shifting up the flow divider. This study assessed the long-term results of EVAR with unimodular endoprosthesis fixed at the aorto-iliac bifurcation (Anatomical FiXation), in a large, unselected cohort.

MATERIALS AND METHODS

In a single-center, retrospective cohort study, 623 patients selectively treated between 1999 and 2016, were analyzed. Follow-up protocol included at least a computed tomography angiography within 3 months and a duplex ultrasound and clinical exam yearly. All enrolled patients were analyzed by 2020. The primary outcomes were technical success, clinical success, and survival. Secondary outcomes included survival-free from late-open-conversion (LOC), reintervention, and endoleaks.

RESULTS

Median age was 74±11 years and the follow-up 93±54 months. The technical success was achieved in 99.4% and the 30-day clinical success was 98.4%. A 5-year clinical success of 97.7% was registered and at 10 years success was 96.7%. The overall survival at 1, 5, 10, and 15 years was 92.4%, 79.5%, 64.9%, and 45.5%, respectively. Six (0.98%) AAA-related death were registered, 3 caused by infection of the endograft and 3 for secondary rupture. LOCs were 9 (1.47%) and reintervention-free survival at 1, 5, 10, and 15 years were 88.4%, 78.0%, 76.2%, and 74.6%, respectively. Freedom from endoleaks was 88.8% at 1 year and 72.7% at 15 years. A total of 63 high-flow endoleaks were registered (43 type I, 7 type IIIa, 12 type IIIb, and 1 type Ib+IIIb). No migrations were recorded, and the graft limb thrombosis rate was 1.14%. From a multivariate analysis resulted that long-term clinical success appeared to be reduced in patients affected by diabetes [odds ratio (OR) 0.24; p=0.04] and in presence of calcified and thrombotic iliac accesses (OR 0.16; p=0.006).

CONCLUSION

EVAR with the Anatomical FiXation was confirmed to be safe, feasible, and effective to prevent AAA rupture in the long term as well. However, the overall survival remains afflicted by cardiovascular accident. The original concept of unibody bifurcated design allowed a very low rate of graft thrombosis and zeroed the risk of migration and related reintervention.

Unibody Endograft Using AFX 2 for Less Invasive and Faster Endovascular Aortic Repair: Protocol for a Multicenter Nonrandomized Study

Background

Since the introduction of endovascular aortic repair (EVAR) for treatment of abdominal aortic aneurysms (AAAs), progressive improvements in results have been achieved. However, conventional bifurcated stent grafts have been proven to have a nonnegligible risk of failure and secondary intervention, principally due to the lack of adequate proximal sealing. The unique AFX 2 Endovascular AAA System (Endologix, Irvine, CA) unibody device, which provides different sealing and fixation features compared with conventional devices, seems to overcome these limitations.

Objective

The aim of this study is to evaluate intraoperative, perioperative, and postoperative results in patients treated with the AFX 2 Endovascular AAA System endografts for elective AAA repair in a large cohort of consecutive patients.

Methods

All eligible EVAR patients will be included in this observational, multicenter, prospective, nonrandomized study. The number of patients to be enrolled is 500.

Results

The primary endpoint of the study is to evaluate the technical and clinical success of EVAR with unibody endografts in short- (90-day), mid- (1-year), and long-term (5-year) follow-up periods. The following secondary endpoints will also be addressed: operative time, intraoperative radiation exposure, contrast medium usage, AAA sac shrinkage at 12-month and 5-year follow-up, and any potential role of patients’ baseline characteristics and device configuration on primary endpoint. The actual start date of the investigation was November 2019. The final patient is expected to be treated by the end of December 2020, and the estimated study completion date is December 2025.

Conclusions

This study will provide verified real-world data on AAAs treated by AFX 2 endografts and followed for a long-term interval.

International Registered Report Identifier (IRRID)

PRR1-10.2196/16959

Meta-analysis of Cumulative Radiation Duration and Dose During EVAR Using Mobile, Fixed, or Fixed/3D Fusion C-Arms

Purpose: To investigate the total fluoroscopy time and radiation exposure dose during endovascular aortic repairs using mobile, fixed, or fixed C-arms with 3-dimensional image fusion (3D-IF). Methods: A systematic search was performed to identify original articles reporting fluoroscopy time (FT) and the kerma area product (KAP) during endovascular aortic repairs. Data were grouped by noncomplex or complex (fenestrated, branched, or chimney) repairs and stratified by type of C-arm. The search identified 27 articles containing 51 study groups (35 noncomplex and 16 complex) that included 3444 patients. Random-effects meta-analysis and meta-regression models were used to calculate the pooled mean estimates of KAP and FT, as well as any effect of equipment or type of intervention. Results are presented with the 95% confidence interval and the statistical heterogeneity ( I2). Results: Within the noncomplex procedure studies, a significant (p<0.001) increase was found in the pooled mean KAP estimate in the fixed C-arm group (181 Gy·cm2, 95% CI 129 to 233; I2=99.7) compared with the mobile C-arm (78 Gy·cm2, 95% CI 59.6 to 97.3; I2=99.6). For complex cases, use of 3D-IF showed a significantly (p<0.001) lower mean KAP (139 Gy·cm2, 95% CI 85 to 191; I2=94%) compared to using fixed C-arms without 3D-IF (487 Gy·cm2, 95% CI 331 to 643; I2=94%). Conclusion: For equivalent fluoroscopy times, the use of a fixed C-arm in noncomplex procedures leads to higher patient radiation doses compared to a mobile C-arm. Complex procedures, which are predominantly performed using fixed C-arms, are associated with the highest radiation dose per intervention. Using fixed C-arms combined with 3D-IF techniques during complex cases might seem an adequate method to compensate for the higher radiation doses measured when a fixed C-arm is used.