Aortic root distensibility after subcoronary stentless valve implantation.
OBJECTIVE
The preservation of aortic root dynamics is considered important for the durability of aortic valve bioprostheses. Stentless heart valves are believed to support physiologic biomechanics. To date, dynamic analysis has been limited to the full root prosthesis, and exclusively in the radial direction. The study aim was to investigate and compare the radial and longitudinal aortic root distensibilities of subcoronary stentless valves, and of stented and native pig valves.


METHODS
Stented pericardial (Mitroflow) or stentless (Solo, Toronto SPV) valve prostheses, or native porcine valves, were investigated in 32 pigs. Postoperatively, 12 sonomicrometry crystals were placed on the aortic root in order to measure aortic root distensibility, in both radial and longitudinal directions.


RESULTS
Sonomicrometry data were obtained from 23 pigs (72%). At the annular level, the native and Solo valves were significantly more distensible in a radial direction than the Mitroflow valve (p = 0.04). However, at the level of the sinotubular junction (STJ), commissures and aorta, the native valve was significantly more distensible than all of the artificial valves (p = 0.006, p = 0.006, and p = 0.02, respectively). The Solo valve exhibited less longitudinal distensibility than the Toronto SPV and Mitroflow valves. The Toronto SPV initiated a radial expansion at the STJ significantly later in the cardiac cycle than did both the Solo and native valves (p = 0.03), but showed no difference compared to the Mitroflow valve. Longitudinal expansion between the annulus and the STJ started significantly earlier for the Solo valve than for both the Toronto SPV (p = 0.03) and Mitroflow (p = 0.02) valves.


CONCLUSIONS
The Solo valve proved to be superior in maintaining annular distensibility immediately following implantation when compared to the Mitroflow valve. The Solo valve did not, however, preserve longitudinal distensibility as well as the other investigated valves. Finally, the Solo valve appeared to provide a more physiologic aortic root expansion pattern than its prosthetic counterparts.
Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Skejby, Aarhus, Denmark. funder@ki.au.dk
Jonas A
JA
Funder
Markus W
MW
Frost
Kaj-Erik
KE
Klaaborg
Per
P
Wierup
Vibeke
V
Hjortdal
Hans
H
Nygaard
J Michael
JM
Hasenkam
D000818:Animals; D001011:Aorta / Q000502:physiology*; D001021:Aortic Valve; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation; D009200:Myocardial Contraction; D011312:Pressure; D013552:Swine