Risk Factor Analysis for the Mal-Positioning of Thoracic Aortic Stent Grafts

Area of Science:

• Vascular Surgery
• Interventional Radiology
• Medical Imaging

Background:

• Thoracic endovascular aortic repair (TEVAR) is a minimally invasive treatment for thoracic aortic pathologies.
• Accurate stent graft placement is crucial for TEVAR success, but mal-positioning can lead to complications.
• Anatomical variations can influence stent graft deployment accuracy.

Purpose of the Study:

• To quantify mal-positioning during TEVAR.
• To analyze how anatomical factors influence stent graft positioning.
• To identify predictors of mal-positioning in TEVAR.

Main Methods:

• Retrospective review of 66 patients undergoing TEVAR between 2007 and 2014.
• Analysis of proximal landing zones (LZ) based on anatomical landmarks (LZ 1, 2, 3).
• Evaluation of pre- and post-operative CT angiography to measure planned vs. achieved LZ.
• Assessment of anatomical factors: iliac diameter, calcification, aortic angulation, and tortuosity index (TI).

Main Results:

• Mal-positioning ranged from 2 to 15 mm, with a cutoff of 11 mm indicating adverse event risk.
• Univariate analysis showed significant association between TI and LZ with mal-positioning (p=0.01, p=0.04).
• Multivariate analysis identified TI as the unique independent risk factor for mal-positioning (OR 241, p=0.05), with TI >1.68 predicting inaccurate deployment.

Conclusions:

• The tortuosity index (TI) is a valuable tool for anticipating challenges in stent graft deployment.
• Calculating TI can help reduce mal-positioning during TEVAR.
• Incorporating TI assessment into pre-procedural planning may improve TEVAR outcomes.