Abstract 2228: Delineation of the Severity and Mechanisms of Aortic Regurgitation Using Multidetector Computed Tomography. Comparison with Transthoracic and Transoesophageal Echocardiography
In patients with aortic regurgitation (AR), both the severity and the mechanisms of AR are critical information in the decision-making process, particularly when reconstructive surgery is contemplated. In daily clinical practice, this information is usually obtained using transthoracic (TTE) and/or transesophageal (TEE) echocardiography. It has been recently suggested that these parameters could also be obtained by multidetector computed tomography (MDCT). Accordingly, the aim of the present study was to investigate the ability of MDCT to delineate both the severity and mechanisms of AR prior to surgery. 42 AR patients (34 men, aged 54 ± 11 years) successfully underwent MDCT, TTE and TEE prior to valve surgery. For analysis of MDCT images, the readers first inspected the aortic valve on long-axis cine mode loops for the presence of incomplete valve closure during diastole. Once an area of malcoaptation was identified, they reconstructed serial contiguous images parallel to the plane of the regurgitant orifice. Then, by using an electronic caliper, they manually traced the inner contours of the anatomical regurgitant orifice (ARO). These measurements were compared to those of the effective regurgitant orifice (ERO) measured by TTE, using the PISA method. The readers also assessed the mechanisms of AR (type I: aortic dilatation, type II: cusp prolapse and type III: restrictive cusp motion) on both MDCT and TEE images. MDCT-derived ARO correlated strongly with PISA-derived ERO (r=0.87, p<0.001). Yet, the ARO by MDCT significantly overestimated the ERO by PISA (27 ± 15 vs 23 ± 11 mm2, p<0.001). According to TEE, 21 patients had type I, 17 had type II and 4 had type III AR. Evaluation of AR mechanisms by MDCT demonstrated an excellent agreement with that by TEE (k=0.80). In pts with chronic AR, MDCT allows to accurately measure the size of the regurgitant orifice and permits correct identification of the mechanisms of AR.