Stented bioprosthetic valve hemodynamics: is the supra-annular implant better than the intra-annular?
OBJECTIVE
The use of stented bioprostheses for aortic valve replacement (AVR) in elderly patients with a small aortic annulus may result in unsatisfactory hemodynamic performance of the prosthesis. To overcome this limitation, new bioprostheses have been designed for complete supra-annular implantation, but the actual hemodynamic advantage of the supra-annular implant over the intra-annular has not been fully investigated. Accordingly, the hemodynamic performance of the same stented bioprosthesis (except for sewing ring design) implanted in the supra-annular and conventional intra-annular seating was compared.


METHODS
Twenty-two patients received an intra-annular implant, and 38 a supra-annular implant. Age (74 +/- 5 versus 76 +/- 5 years, p = 0.54), gender (55% versus 50% males, p = 0.79) and body surface area (1.74 +/- 0.2 versus 1.81 +/- 0.2 m2, p = 0.13) were similar in both subgroups, who underwent echocardiography at 8 +/- 2 and 6 +/- 2 months after surgery, respectively (p = 0.09).


RESULTS
The two patient subgroups had similar preoperative left ventricular outflow tract diameters (2.06 +/- 0.2 and 2.1 +/- 0.2 cm; p = 0.62), average size of implanted prosthesis (21.0 and 21.3 mm; p = 0.44) and mean transprosthetic flow rate (246 +/- 70 and 218 +/- 58 ml/s; p = 0.12). Mean (8 +/- 3 and 19 +/- 8 mmHg, p < 0.0001), and peak (17 +/- 6 and 40 +/- 13 mmHg; p < 0.0001) transprosthetic gradients were lower, and mean effective orifice area (EOA) (1.78 +/- 0.4 and 1.45 +/- 0.5 cm2, p = 0.006) was higher in patients with supra-annular implants than in those with intraannular. The incidence of patient-prosthesis mismatch (EOA index < 0.85 cm2/m2) decreased from 50% to 34% (p < 0.0001), with no case of severe mismatch using the supra-annular implant. During follow up, a left ventricular mass reduction occurred in patients with supra-annular implants (from 225 +/- 110 to 173 +/- 59 g/m2; p < 0.03), but not in patients with intra-annular implants (173 +/- 62 and 186 +/- 64 g/m2; p = 0.87)


CONCLUSIONS
The study results showed that, compared to intra-annular implantation, supra-annular implantation of bioprosthetic stented valves in the aortic position was associated with a significantly better hemodynamic performance of the prosthesis and significant regression of left ventricular hypertrophy.
Badano
Luigi P
LP
Department of Cardiopulmonary Sciences, A.O. S. Maria della Misericordia, Udine, Italy. badano.luigi@aoud.sanita.fvg.it
Pavoni
Daisy
D
Musumeci
Sergio
S
Frassani
Romeo
R
Gianfagna
Pasquale
P
Baldassi
Mara
M
Tursi
Vincenzo
V
Mazzaro
Enzo
E
Zakja
Edlira
E
Fioretti
Paolo M
PM
Livi
Ugolino
U
D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001024:Aortic Valve Stenosis / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D001705:Bioprosthesis; D001783:Blood Flow Velocity / Q000502:physiology*; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000295:instrumentation*; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging / Q000209:etiology / Q000517:prevention & control; D008297:Male; D011446:Prospective Studies; D011474:Prosthesis Design; D012720:Severity of Illness Index; D015607:Stents; D016896:Treatment Outcome