Acute in vivo evaluation of a new stentless mitral valve.
OBJECTIVE
We have developed a stentless pericardial mitral valve prosthesis in 2 configurations; the purposes of this acute study in sheep were to assess (1) valve design and implant technique; (2) valve performance; and (3) acute effects on postimplant left ventricular function.


METHODS
A stentless bovine pericardial bileaflet valve was developed with the intent to preserve annular-papillary muscle continuity. This valve, in 2 configurations-with (n = 5) and without (n = 5) flap chordae-was implanted in 10 sheep (mean weight 73 +/- 9 kg). Epicardial echocardiography was performed to assess valve performance. Load-independent left ventricular function was also estimated before implantation (baseline), 1 hour after discontinuing cardiopulmonary bypass (rest), and during dobutamine stimulation using conductance technology.


RESULTS
Implantation was easily accomplished for both configurations. Both configurations had low transvalvular pressure (mean 2.1 +/- 1.2 mm Hg at rest; 2.2 +/- 1.0 mm Hg with dobutamine stimulation with flap chordae; 1.7 +/- 0.5 mm Hg and 1.6 +/- 0.3 mm Hg without flap chordae). No mitral regurgitation was observed in 8 sheep, and mild regurgitation was seen in 2 sheep. Compared with baseline, slope of maximum rate of change of left ventricular pressure-end-diastolic volume relation increased with stimulation both with flap chordae (+52 +/- 41 mm Hg x s(-1)x mL(-1), P = .0005) and without (+20 +/- 12 mm Hg x s(-1) x mL(-1), P = .003).


CONCLUSIONS
Both configurations of this newly designed stentless mitral bioprosthesis, which preserves annular-papillary muscle continuity using different novel surgical implantation techniques, demonstrated reliable valve performance, with low transvalvular pressure gradients, minimal regurgitation, and acutely preserved postimplant left ventricular function. Further chronic study is needed to verify these results and evaluate reliability of implantation procedures, biocompatibility, and durability.
Navia
Jose L
JL
Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, Cleveland, Ohio 44195, USA. naviaj@ccf.org
Doi
Kazuyoshi
K
Atik
Fernando A
FA
Fukamachi
Kiyotaka
K
Kopcak
Michael W
MW
Dessoffy
Raymond
R
Ruda-Vega
Pablo
P
Garcia
Mario
M
Houghtaling
Penny L
PL
Martin
Maureen
M
Blackstone
Eugene H
EH
McCarthy
Patrick M
PM
Lytle
Bruce W
BW
D000818:Animals; D001705:Bioprosthesis; D005240:Feasibility Studies; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000295:instrumentation*; D008943:Mitral Valve; D023421:Models, Animal; D011474:Prosthesis Design; D012756:Sheep; D015607:Stents; D016277:Ventricular Function, Left / Q000502:physiology*