Abstract 17722: Does Aortic Resection without an Open Distal and Hemi-Arch Procedure Address all Regions at Risk of Progression in Bicuspid Aortopathy?

Abstract

Introduction: Aggressive aortic resection strategies for bicuspid aortic valve (BAV) patients with significant aortopathy are sometimes warranted. 4D flow MRI can identify regions of the aorta with elevated wall shear stress (WSS) that may be at risk of disease progression and thus should be resected during aneurysm repair. This study assesses the efficacy of standard aortic resection practices to include areas at risk as determined by preoperative imaging. Methods: 13 BAV patients (51±17 yrs) undergoing ascending aortic repair received preoperative 4D flow MRI. 10 age-matched normal subjects (50±14 yrs) with healthy tricuspid aortic valves were used to determine the range of physiologically normal WSS. Patient WSS above the healthy 95% confidence interval classified tissue at risk. The surgeon was blinded to the results and postoperative MRI identified the exact region of resection. Results: Preoperative mean aortic diameter was 4.7±0.7 cm; the age-matched control diameter was 2.9±0.5 cm (P<0.001). 38% of patients had severe aortic stenosis. All patients had WSS above the physiologic norm. All 5 patients with open distal and hemi-arch repair had complete removal of “at-risk” tissue as defined by elevated WSS. In all 5 cases, resection with the clamp on would have resulted in residual at risk regions. Of the 8 patients with the occluding clamp left on: 4 had regions at risk that matched/were smaller than the resected regions (-9±6% of resection area) while 4 had remaining tissue at risk (36±22% of resection area). The average at risk region remaining was 14±28% of the resection area. Conclusions: In selected patients with BAV, aggressive resection using open distal/hemi-arch repair is necessary for complete resection of tissue at risk of disease progression. Less aggressive resections without an open distal anastomosis does not always completely remove “at risk” regions. With further validation, 4D flow MRI could be used to guide patient-specific resection strategies.