Three-Dimensional Holographic Guidance, Navigation, and Control (3D-GNC) for Endograft Positioning in Porcine Aorta: Feasibility Comparison With 2-Dimensional X-Ray Fluoroscopy.

Objectives: Intraprocedural deployment of endovascular devices during complex aortic repair with 2-dimensional (2D) x-ray fluoroscopic guidance poses challenges in terms of accurate delivery system positioning and increased risk of x-ray radiation exposure with prolonged fluoroscopy times, particularly in unfavorable anatomy. The objective of this study was to assess feasibility of using an augmented reality (AR) system to position and orient a modified aortic endograft delivery system in comparison with standard fluoroscopy.

Materials And Methods: The 3-dimensional guidance, navigation, and control (3D-GNC) prototype system was developed for eventual integration with the Intra-Operative Positioning System (IOPS, Centerline Biomedical, Cleveland, OH) to project spatially registered 3D holographic representations of the subject-specific aorta for intraoperative guidance and coupled with an electromagnetically (EM) tracked delivery system for intravascular navigation. Numerical feedback for controlling the endograft landing zone distance and ostial alignment was holographically projected on the operative field. Visualization of the holograms was provided via a commercially available AR headset. A Zenith Spiral-Z AAA limb stent-graft was modified with a scallop, 6 degree-of-freedom EM sensor for tracking, and radiopaque markers for fluoroscopic visualization. In vivo, 10 interventionalists independently positioned and oriented the delivery system to the ostia of renal or visceral branch vessels in anesthetized swine via open femoral artery access using 3D-GNC and standard fluoroscopic guidance. Procedure time, fluoroscopy time, cumulative air kerma, and contrast material volume were recorded for each technique. Positioning and orientation accuracy was determined by measuring the target landing-zone distance error (δ) and the scallop-ostium angular alignment error (θ) using contrast-enhanced cone beam computed tomography imaging after each positioning for each technique. Mean, standard deviation, and standard error are reported for the performance variables, and Student's tests were used to evaluate statistically significant differences in performance mean values of 3D-GNC and fluoroscopy.

Results: Technical success for the use of 3D-GNC to orient and position the endovascular device at each renal-visceral branch ostium was 100%. 3D-GNC resulted in 56% decrease in procedure time in comparison with standard fluoroscopic guidance (p<0.001). The 3D-GNC system was used without fluoroscopy or contrast-dye administration. Positioning accuracy was comparable for both techniques (p=0.86), while overall orientation accuracy was improved with the 3D-GNC system by 41.5% (p=0.008).

Conclusions: The holographic 3D-GNC system demonstrated improved accuracy of aortic stent-graft positioning with significant reductions in fluoroscopy time, contrast-dye administration, and procedure time.