A new "angle" on aortic neck angulation measurement

The Correlation of Aortic Neck Angle and Length in Abdominal Aortic Aneurysm with Severe Neck Angulation for Prediction of Intraoperative Neck Complications and Postoperative Outcomes after Endovascular Aneurysm Repair

OBJECTIVES

Endovascular aneurysm repair (EVAR) in a hostile neck has been associated with adverse outcomes. We aimed to determine the association of infrarenal aortic neck angle and length and establish an optimal cutoff value to predict intraoperative neck complications and postoperative outcomes.

METHODS

This was a retrospective review of patients with an intact infrarenal abdominal aortic aneurysm (AAA) with severe neck angulation (>60 degrees) who underwent EVAR from October 2010 to October 2018. Demographic data, aneurysm morphology, and operative details were collected. The ratio of neck angle and length was calculated as the optimal cutoff value of the aortic neck angle-length index. The patients were categorized into two distinct groups using latent profile analysis, a statistical technique employed to identify concealed subgroups within a larger population by examining a predetermined set of variables. Intraoperative neck complications, adjunct neck procedures, and early and late outcomes were compared.

RESULTS

115 patients were included. Group 1 (G1) had 95 patients with an aortic neck angle-length index ≤ 4.8, and Group 2 (G2) had 20 patients with an aortic neck angle-length index > 4.8. Demographic data and aneurysm morphology were not significantly different between groups except for neck length (p < 0.001). G2 had more intraoperative neck complications than G1 (21.1% vs. 55%, p = 0.005). Adjunctive neck procedures were more common in G2 (18.9% vs. 60%, p < 0.001). The thirty-day mortality rate was not statistically different. G1 patients had a 5-year proximal neck re-intervention-free rate comparable to G2 patients (93.7% G1 vs. 87.5% G2, p = 0.785). The 5-year overall survival rate was not statistically different (59.9% G1 vs. 69.2% G2, p = 0.891).

CONCLUSIONS

Patients with an aortic neck angle-length index > 4.8 are at greater risk of intraoperative neck complications and adjunctive neck procedures than patients with an aortic neck angle-length index ≤ 4.8. The 5-year proximal neck re-intervention-free rate and the 5-year survival rate were not statistically different. Based on our findings, this study suggests that the aortic neck angle-length index is a reliable predictor of intraoperative neck complications during EVAR in AAA with severe neck angulation.

Evaluation of an in vivo preclinical model for human middle meningeal artery embolization using the posterior intercostal artery of the swine

BACKGROUND

Embolization of the middle meningeal artery (MMA) is a promising minimally invasive technique that is gaining traction in the treatment of chronic subdural hematoma. Unfortunately, the human meninges and associated arteries are significantly larger than those of conventional laboratory animals, making the development of a clinically relevant animal model for testing of embolization agents elusive.

OBJECTIVE

To introduce the posterior intercostal artery (PIA) model in swine and provide anatomical, angiographic, histological, and procedural data to validate its relevance in modeling the human MMA.

METHODS

In human cadaveric specimens, 3D angiograms of the internal maxillary arteries (n=6) were obtained and the dura with MMA were harvested and histologically processed. Angiographic and histologic data of the human MMA were compared with the swine PIA (three animals). Then, embolization of the PIA (n=48 arteries) was conducted with liquid embolization agent (Onyx, Medtronic), and angiographic and histological results were assessed acutely (four animals) and after 30 days (two animals).

RESULTS

The human MMA has equivalent diameter, length, branching pattern, 3D trajectory, and wall structure to those of swine PIAs. Each swine has 12 to 14 PIAs (6-7 per side) suitable for acute or chronic embolization, which can be performed with high fidelity using the same devices, agents, and techniques currently used to embolize the MMA. The arterial wall structure and the acute and chronic histological findings in PIAs after embolization are comparable to those of humans.

CONCLUSIONS

This PIA model in swine could be used for research and development; objective benchmarking of agents, devices, and techniques; and in the training of neurointerventionalists.