Structural determinants of aortic regurgitation in type A dissection and the role of valvular resuspension as determined by intraoperative transesophageal echocardiography

Disruption of the aortic root by dissection often produces significant aort ic regurgitation (AR). Resuspension of the native valve usually reestablish es competence. The mechanisms of this complex process are poorly understood . We used intraoperative transesophageal echocardiography to characterize t he in vivo aortic root structure of type A aortic dissection and the change s brought about by native valve resuspension. Intraoperative transesophagea l echocardiograms were obtained from 34 patients with type A dissection and aortic resuspension between January 1990 and April 1997. The severity of A R, aortic root diameter, circumference of the aortic annulus, percentage of the annulus dissected, and presence of leaflet prolapse were assessed in m ultiple planes. Preoperatively, AR of varying degree was present in 25 pati ents (73%). Multivariate analysis revealed that preoperative AR was most re lated to percentage of the annulus dissected (p <0.0001) and less related t o root diameter (p <0.01), Leaflet prolapse was predicted by percent aortic annulus dissected (p <0.0001), After resuspension, annular dissection and leaflet prolapse were no longer present. Postoperative AR was significantly decreased fram preoperative AR (p <0.0001) and was considered trace to mil d. Although postoperative root diameter and annular circumference decreased (p <0.001), individual reductions in AR did not correlate with individual changes in root diameter or annular circumference. The degree of dissection of the valve annulus is the most significant determinant of leaflet prolap se and AR severity. Overall size of the aortic root also contributes to AR. Surgical resuspension significantly decreases root size, but its primary b enefit is restoration of the structural integrity of the aortic annulus. (C )2000 by Excerpta Medica, Inc.