AUGMENTED REALITY SYSTEM FOR ULTRASOUND GUIDANCE OF TRANSCATHETER AORTIC VALVE REPLACEMENT

Abstract

Transcatheter aortic valve replacement (TAVR) relies on fluoroscopy and nephrotoxic contrast medium for valve deployment. We propose an alternative guidance system using augmented reality (AR) and transesophogeal echocardiography (TEE) to guide TAVR deployment. The goals of this study were to determine how consistently the aortic valve annulus is defined from TEE using different aortic valve landmarks, and to compare AR guidance to fluoroscopic guidance of TAVR deployment in an aortic root model. Magnetic tracking sensors were integrated into the TAVR catheter and TEE probe, allowing these tools to be displayed in an AR environment (Figure 1). Variability in identifying aortic valve commissures and cuspal nadirs was assessed using TEE aortic root images. To compare AR guidance of TAVR deployment to fluoroscopic guidance, a TAVR stent was deployed ten times in the aortic root model using each of the two guidance systems. Commissures and nadirs were both investigated as features for defining the valve annulus in the AR guidance system. The commissures were identified more consistently than the nadirs with an intraobserver variability of 2.2mm and 3.8mm respectively and an interobserver variability of 3.3 and 4.7mm respectively. The precision of TAVR deployment using fluoroscopic guidance was 3.4mm while the precision of AR guidance was 2.9mm and its overall accuracy was 3.4mm indicating similar performance. Aortic valve commissures can be identified more reliably than cuspal nadirs from TEE. The AR guidance system achieved similar deployment accuracy to fluoroscopy while eliminating the use and consequences of nephrotoxic contrast and radiation.