Development of a new experimental model for total exclusion of the right heart without the aid of cardiopulmonary bypass.
A new experimental model for the total exclusion of the right heart was successfully developed in mongrel dogs without the use of cardiopulmonary bypass. A Y-shaped conduit was constructed with tube grafts spirally stented on the exterior (10 mm in diameter), and each upper limb of the conduit was provided with a 30F cannula. The foot of the conduit was anastomosed with the main pulmonary artery in an end-to-side way with a side clamp. After a closed atrioseptostomy was performed with a special knife of our design, the upper limbs of the graft were connected to the superior and inferior venae cavae by a cannulation method. The operative procedure was completed by tightening the occluding snares around the venae cavae and ligating the root of the pulmonary artery and azygos vein. Thus, without any use of the right atrium, venous blood from the venae cavae was totally diverted to the pulmonary circulation via the conduit, and only the coronary venous return was shunted to the left atrium. Five consecutive dogs tolerated the operative procedure. No pressure gradients were observed between the pulmonary arteries and venae cavae. The circulation with this model was able to be sufficiently sustained with mean pulmonary arterial pressures of about 25 mm Hg, and no significant changes were shown in the left ventricular pump function from the preoperative state. However, the decrease in the mean pulmonary artery pressure to 20 mm Hg resulted in severe circulatory failure, and two of the five dogs succumbed to this condition. Our new model will be useful for studying the hemodynamic characteristics of the circulation after operations that result in total exclusion of the right heart.
Nawa
S
S
Second Department of Surgery, Okayama University Medical School, Japan.
Irie
H
H
Takata
K
K
Sugawara
E
E
Teramoto
S
S
D000818:Animals; D001794:Blood Pressure; D002302:Cardiac Output; D006348:Cardiac Surgical Procedures / Q000379:methods*; D002315:Cardiopulmonary Bypass; D004285:Dogs; D004562:Electrocardiography; D006439:Hemodynamics; D008955:Models, Cardiovascular