Open resection for subvalvular aortic stenosis in dogs.
OBJECTIVE
To describe the surgical technique for open resection of congenital subvalvular aortic stenosis in dogs and to determine outcome of dogs undergoing the procedure.


METHODS
Uncontrolled clinical trial.


METHODS
17 dogs with congenital discrete subvalvular aortic stenosis.


METHODS
Dogs were placed on cardiopulmonary bypass by catheterizing the femoral artery and both vena cavae. The aorta was cross clamped, and cold cardioplegia solution was administered. The aortic root then was opened with a curvilinear incision. A subvalvular discrete fibrous ring was resected in all dogs. Septal myectomy was performed simultaneously on 11 dogs.


RESULTS
15 of 17 dogs survived the operation and were discharged from the hospital. Mean +/- SD maximal instantaneous aortic systolic pressure gradient measured by means of Doppler echocardiography was significantly reduced from 119 +/- 42 mm of Hg before surgery to 41 +/- 10 mm of Hg 12 months after surgery. Despite substantial reduction in the systolic pressure gradient, 4 of 15 dogs died suddenly between 7 days and 30 months after surgery. Three of the 4 dogs that died suddenly had pressure gradients > or = 180 mm of Hg and ventricular tachycardia before surgery. Eleven dogs were still alive between 1 and 48 months after surgery.


CONCLUSIONS
The procedure resulted in substantial reductions in systolic pressure gradients in dogs with severe congenital subvalvular aortic stenosis. However, some dogs with severe aortic stenosis died suddenly after surgery. Thus, this surgery should not be considered curative. Proof of a survival benefit in dogs undergoing this surgery will have to await longer term follow-up.
Monnet
E
E
Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA.
Orton
E C
EC
Gaynor
J S
JS
Boon
J
J
Wagner
A
A
Linn
K
K
Eddleman
L A
LA
Brevard
S
S
D000818:Animals; D001024:Aortic Valve Stenosis / Q000151:congenital / Q000601:surgery / Q000662:veterinary*; D001794:Blood Pressure; D002315:Cardiopulmonary Bypass / Q000662:veterinary*; D016757:Death, Sudden, Cardiac / Q000662:veterinary; D004283:Dog Diseases / Q000151:congenital / Q000601:surgery*; D004285:Dogs; D015150:Echocardiography, Doppler / Q000662:veterinary; D006345:Heart Septal Defects, Ventricular / Q000601:surgery / Q000662:veterinary; D011183:Postoperative Complications / Q000662:veterinary; D016896:Treatment Outcome