Self-expandable valved stent of large size: off-bypass implantation in pulmonary position.
OBJECTIVE
To evaluate the feasibility of the off-bypass implantation of a self-expandable valved stent of large size in pulmonary position.


METHODS
A glutaraldehyde preserved valved bovine jugular xenograft with internal diameter = 22 mm, mounted in two rings of nitinol 'Z' stent, expandable from 7 to 24 mm of internal diameter, was acutely evaluated in 6 adult pigs, mean body weight 55.6 kg (range 47-67 kg). Through a stent-graft delivery system (24 French) the self expandable valved stent was implanted off-bypass in pulmonary valve position by trans-ventricular approach through median sternotomy.


RESULTS
The mean diameter of the main pulmonary artery measured was 21.7 +/- 1.6 mm. The mean length of the self expandable valved stent was 23.1 +/- 0.7 mm, the mean internal diameter 21.6 +/- 0.7 mm and the mean external diameter 26.3 +/- 0.7 mm. The mean peak pressure gradient recorded across the valve was 6.33 +/- 2.8 mmHg (range 4.5-9.6 mmHg) at Doppler echocardiography, and 4.5 +/- 3.1 mmHg (range 0-7 mmHg) at invasive measurement, with a pulmonary blood flow of 3.03 +/- 0.05 l/min. Intra-vascular ultrasound showed complete opening and closure of the valve (mean area reduction from 315.08 +/- 54.13 to 0 mm2).


CONCLUSIONS
(a) Off-bypass implantation of self-expandable valved stent is feasible in pulmonary position; (b) off-bypass surgical approach allows for valved stent implantation of adult size with adequate hemodynamic functioning; and (c) intra-vascular ultrasound makes implantation and evaluation easy and reproducible.
Zhou
Jun Qing
JQ
Cardiothoracic Department, The No. 1 People's Hospital of Shaoxing, Zhejiang, China.
Corno
Antonio F
AF
Huber
Christophe H
CH
Tozzi
Piergiorgio
P
von Segesser
Ludwig K
LK
D000818:Animals; D001705:Bioprosthesis; D019917:Blood Vessel Prosthesis Implantation; D002417:Cattle; D018618:Echocardiography, Doppler, Color; D004867:Equipment Design; D005240:Feasibility Studies; D023421:Models, Animal; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000601:surgery*; D011664:Pulmonary Valve / Q000000981:diagnostic imaging / Q000601:surgery*; D015607:Stents; D013552:Swine; D018084:Ultrasonography, Interventional