Off-pump replacement of the pulmonary valve in large right ventricular outflow tracts: a hybrid approach.
BACKGROUND
Percutaneous pulmonary valve replacement has recently been introduced and is under investigation in humans. This technique is, however, limited to patients with a right ventricular outflow tract that does not exceed 22 mm in diameter. We report our experience of off-pump pulmonary valve replacement using a hybrid approach in animals with large right ventricular outflow tracts.


METHODS
Eight ewes were included in the protocol and were equally divided into 2 groups. A left thoracotomy was first performed, and the main pulmonary artery was banded by using 2 radiopaque rings with a diameter of 18 mm that allowed for further pulmonary valve replacement. We then intended to implant a valved stent either percutaneously (group 1) or through a transventricular approach (group 2). All animals were killed after valve implantation. The operation allowed the pulmonary diameter to be reduced from 30 to 17.6 mm.


RESULTS
The right ventricular pressure did not significantly increase after reduction of the pulmonary artery diameter (25 vs 36 mm Hg). Subsequent pulmonary valve replacement through a percutaneous or a transventricular approach was always possible without any requirement for extracorporeal circulation. All devices were successfully delivered inside the pulmonary artery banding and were functioning perfectly at early evaluation.


CONCLUSIONS
Implantation of a pulmonary valve is possible in ewes through a hybrid approach when the right ventricular outflow tract exceeds 22 mm in diameter. This involves both surgeons and interventionists and allows for a staged procedure in which the valvulation is performed percutaneously or, for a combined hybrid approach, in which the valve is implanted off pump transventricularly during the same operation.
Boudjemline
Younes
Y
Service de Cardiologie pédiatrique, Hôpital Necker Enfants Malades, Paris, France. younes.boudjemline@nck.ap-hop-paris.fr
Schievano
Silvia
S
Bonnet
Caroline
C
Coats
Louise
L
Agnoletti
Gabriella
G
Khambadkone
Sachin
S
Bonnet
Damien
D
Deanfield
John
J
Sidi
Daniel
D
Bonhoeffer
Philipp
P
D000818:Animals; D006328:Cardiac Catheterization; D002404:Catheterization / Q000295:instrumentation; D005260:Female; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000295:instrumentation / Q000379:methods*; D006352:Heart Ventricles / Q000601:surgery*; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D011664:Pulmonary Valve / Q000601:surgery*; D011859:Radiography; D012756:Sheep; D015607:Stents; D013908:Thoracotomy; D017725:Ventricular Pressure / Q000502:physiology