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

Impact of Cross-Limb Stent-Graft Configuration on Hemodynamics in Abdominal Aortic Aneurysm Interventional Therapy

PURPOSE

The cross-limb (CL) technique is a commonly used endovascular treatment for addressing unfavorable anatomical features in patients with abdominal aortic aneurysm (AAA). The configuration of CL stent-graft plays a critical role in determining the postoperative hemodynamic properties and physiological behaviors, which ultimately impact the efficacy and safety of endovascular AAA treatment. This study aims to investigate the relationship between hemodynamics and CL stent-graft configuration from a hemodynamic perspective.

METHODS

Five distinct geometric models of cross-limb (CL) stent-graft configurations were constructed by optimizing the real clinical computed tomography angiography (CTA) data. These models varied in main body lengths and cross angles and were used to perform numerical simulations to analyze various hemodynamic parameters. Flow pattern, distribution of wall shear stress (WSS)-related parameters, localized normalized helicity (LNH), pressure drop, and the displacement force of all models were examined in this paper.

RESULTS

In patient-specific cases, helical flow and WSS increase with the main body. However, it also generated secondary flow in localized areas, leading to increased oscillation in the WSS direction. Notably, increasing the stent graft's main body length or decreasing the cross angle reduced the displacement force exerted on the stent-graft. Reducing the cross angle did not significantly alter the hemodynamic characteristics.

CONCLUSION

In the clinical practice of CL deployment, it is crucial to carefully consider the stent-graft configuration and the patient specific to achieve optimal postoperative outcomes. This study provides valuable insights for guiding stent selection and treatment planning in patients with abdominal aortic aneurysm undergoing CL techniques, from a hemodynamic perspective.

Fast-Track Management of Concurrent Percutaneous Coronary Intervention in Patients Scheduled for Endovascular Abdominal Aortic Aneurysm Repair

PURPOSE

To investigate the safety and efficacy of fast-track management of concurrent percutaneous coronary intervention (PCI) in patients with abdominal aortic aneurysm scheduled for endovascular aortic aneurysm repair (EVAR).

MATERIALS AND METHODS

Eligible patients with abdominal aortic aneurysm who received EVAR from January 2011 to December 2019 were included in this retrospective cohort study. Propensity score (PS)-matched analysis was used to balance the baseline between the fast-track and standard control (EVAR without significant coronary artery disease) groups. Effects of fast-track management on short-term and midterm outcomes were evaluated via Cox proportional hazard regression and logistic regression analyses with corresponding hazard ratio (HR) or odds ratio (OR) and associated 95% confidence intervals (95% CIs), respectively.

RESULTS

The study included 669 patients (73 fast-track and 596 standard control). Compared with the standard control group, no significant difference was found regarding major adverse cardiac events (HR 0.78, 95% CI [0.36, 1.68], p=0.519), overall mortality (HR 0.63, 95% CI [0.25, 1.55], p=0.315), and 30-day major hemorrhage events (OR 1.01, 95% CI [0.99, 1.03], p=0.514). The results were consistent in the PS-matched cohorts regarding major adverse cardiac events (HR 0.57, 95% CI [0.25, 1.29], p=0.176), overall mortality (HR 0.43, 95% CI [0.17, 1.11], p=0.820), and 30-day major hemorrhage events (OR 1.00, 95% CI [0.05, 10.61], p=0.999). Similar results were found in the subgroup analyses concerning fast-track management of 2-week intervals and patients with high age-adjusted Charlson comorbidity index.

CONCLUSIONS

Under appropriate perioperative care, shortening the time interval between PCI and EVAR to 1 month, or even 2 weeks, seemed to be safe and effective. Short-term and midterm cardiovascular and survival outcomes were comparable with patients who underwent standard EVAR without significant coronary artery disease.

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].

A Comparative Study on the Hemodynamic Performance Within Cross and Non-cross Stent-Grafts for Abdominal Aortic Aneurysms With an Angulated Neck

Objectives: Cross-limb stent grafts for endovascular aneurysm repair (EVAR) are often employed for abdominal aortic aneurysms (AAAs) with significant aortic neck angulation. Neck angulation may be coronal or sagittal; however, previous hemodynamic studies of cross-limb EVAR stent grafts (SGs) primarily utilized simplified planar neck geometries. This study examined the differences in flow patterns and hemodynamic parameters between crossed and non-crossed limb SGs at different spatial neck angulations.

Methods: Ideal models consisting of 13 cross and 13 non-cross limbs were established, with coronal and sagittal angles ranging from 0 to 90°. Computational fluid dynamics (CFD) was used to capture the hemodynamic information, and the differences were compared.

Results: With regards to the pressure drop index, the maximum difference caused by the configuration and angular direction was 4.6 and 8.0%, respectively, but the difference resulting from the change in aneurysm neck angle can reach 27.1%. With regards to the SAR-TAWSS index, the maximum difference caused by the configuration and angular direction was 7.8 and 9.8%, respectively, but the difference resulting from the change in aneurysm neck angle can reach 26.7%. In addition, when the aneurysm neck angle is lower than 45°, the configuration and angular direction significantly influence the OSI and helical flow intensity index. However, when the aneurysm neck angle is greater than 45°, the hemodynamic differences of each model at the same aneurysm neck angle are reduced.

Conclusion: The main factor affecting the hemodynamic index was the angle of the aneurysm neck, while the configuration and angular direction had little effect on the hemodynamics. Furthermore, when the aneurysm neck was greatly angulated, the cross-limb technique did not increase the risk of thrombosis.

Meta-Analysis of the Crossed Versus Standard Limb Configuration in Endovascular Aneurysm Repair

OBJECTIVE

To investigate whether the crossed-limb technique confers better or worse clinical outcomes compared to the standard straight limb configuration in standard endovascular aneurysm repair (EVAR).

METHODS

We conducted a systematic review to identify studies comparing outcomes of EVAR with the crossed versus standard limb configuration. MEDLINE, EMBASE, CINAHL, and CENTRAL were searched in March 2021 using the Healthcare Databases Advanced Search interface developed by the National Institute for Heath and Care Excellence. The risk of bias was assessed with the Newcastle-Ottawa scale (NOS) and the Risk Of Bias In Non-randomized Studies - of Interventions (ROBINS-I) tool. Summary estimates were calculated using the odds ratio (OR), risk difference (RD), or mean difference (MD) and 95% confidence interval (CI), applying the Mantel-Haenszel or inverse variance statistical method. Random-effects models were employed.

RESULTS

Four observational studies qualified for inclusion, reporting a total of 1132 patients. All presented contemporary experiences. Baseline clinical characteristics were largely similar between patients with and without the crossed-limb configuration, but the anatomy tended to be less favourable in patients treated with the crossed-limb technique. No statistically significant difference was found in the primary outcomes: limb occlusion (OR 1.44, 95% CI 0.65 - 3.19), type Ib endoleak (RD 0.01, 95% CI -0.03 - 0.04), type III endoleak (RD 0.01, 95% CI -0.01 - 0.03); or secondary outcomes: perioperative mortality (RD 0.00, 95% CI -0.03 - 0.03), type Ia endoleak (RD 0.00, 95% CI -0.03 - 0.02), type II endoleak (OR 1.38, 95% CI 0.51 - 3.74), procedure duration (MD 18.07 min, 95% CI -1.14-37.29). Inconsistency across studies was low for all outcomes. The studies were judged to be of high quality on the NOS. The main bias identified using the ROBINS-I tool was due to confounding.

CONCLUSIONS

The crossed-limb technique was not found to confer inferior clinical outcomes in the medium term compared to the standard limb configuration in patients who undergo standard EVAR.