Several pathogenetic mechanisms account for the association of the ascending aorta dilation with aortic valve dysfunction. Functional aortic insufficiency can derive from medial degeneration of the aortic wall and annuloaortic ectasia; leaflet structural disease can determine root dilation by increasing aortic wall stress in case of both regurgitation and stenosis; aortic valve disease and aortic aneurysm can however coexist due to two different intrinsic etiologies. In the attempt to best tailor the surgical correction of such conditions to the underlying causative mechanism, several technical options have already been developed including composite or separate aortic valve and root replacement, valve-sparing operations, and aortoplasty techniques. The criteria for surgical indication cannot leave the underlying pathogenesis out of consideration as well. The newly acquired knowledge in the basic research on this topic is expected to affect the approach to the individual patient in the future.
"Notably, abnormal flow patterns also occur in patients with stenosis of their initially normal TAV. It was reported that in these patients the resulting AAD is symmetrical, “pear” or “teardrop” shaped, while in patients with CBAV, the AAD is convex toward the right antero-lateral aspect, where degenerative media changes were also found to be the most severe . These observations agree with our own, in which we found stress-overload at the same location in patients with “normally” functioning CBAVs with no pressure gradients or regurgitation . "
[Show abstract][Hide abstract] ABSTRACT: The cause of ascending aortic dilatation occurring in patients with congenitally bicuspid aortic valves was investigated.
Flow patterns through human aortic roots with congenitally bicuspid aortic valves as well as through porcine constricted aortas were studied in a left heart simulator. Vibration was recorded as a measure of turbulence in the post-stenotic segment. Histological changes in fetal aortas with isolated congenitally bicuspid aortic valves were compared to fetal aortas with congenitally bicuspid aortic valves and hypoplastic left hearts, as well as to normal fetal aortas with tricuspid aortic valves.
Congenitally bicuspid aortic valves were anatomically stenotic even in the absence of pressure gradients and without history of relevant symptoms. Histology of the aortic wall in isolated fetal congenitally bicuspid aortic valves was similar to that of fetal aortas with normal tri-leaflet aortic valves, but was abnormal if congenitally bicuspid aortic valves was associated with other cardiovascular anomalies. Flow studies revealed that turbulence and vibration in the post-stenotic aortic segments generated by the stenosis were proportional to the degree of the narrowing.
Congenitally bicuspid aortic valves are inherently stenotic, asymmetrical, generate turbulence and vibration. This not only leads to early failure but also to injury of the ascending aortic wall and ascending aortic dilatation. The more progressive form of ascending aortic dilatation occurs in patients where congenitally bicuspid aortic valves is combined with other inborn anomalies and may require a radical procedure (replacement).
[Show abstract][Hide abstract] ABSTRACT: Experience with a new operation for patients with aortic valve disease and aneurysm or dissection of the ascending aorta is described. Twenty-four patients aged 66-87 years were operated on using a subcoronary implantation technique with a stentless aortic valve bioprosthesis and an extension using a vascular tube prosthesis. No major adverse cardiac events were observed in the postoperative period. This operation offers a safe alternative to the technically more demanding procedures of composite bioprosthetic ascending aortic replacement or full root replacement.
Asian cardiovascular & thoracic annals 11/2008; 16(5):355-60. DOI:10.1177/021849230801600503
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