Direct atrioventricular versus atriopulmonary connection: a comparative experimental study.

A study of 31 dogs, divided into two groups, was conducted to compare direct atrioventricular with atriopulmonary connection using a valved conduit to treat tricuspid atresia. The first group (n = 9) acted as controls. In the second group (n = 22), an experimental model was established for direct atrioventricular connection that could be converted to atriopulmonary connection. In subgroup A (n = 11), the blood from the right atrium (RA) was conducted to a haemodynamically effective residual right ventricle (RV), whereas in subgroup B (n = 11) the blood was conducted from the RA to an ineffective residual RV. There were haemodynamic advantages of atrioventricular connection in subgroup A. No such differences were found between the two surgical techniques in subgroup B. In both subgroups, light external compression of the pulmonary artery produced a profound deterioration in the haemodynamic state. The technique of direct atrioventricular connection does not appear to offer any advantages as a method of atriopulmonary bypass.

[Experimental evaluation of the role of the coronary sinus pressure in the regulation of coronary return volume via the coronary sinus. Surgical considerations in atrio-pulmonary diversion procedures]. / Valoración experimental del papel de la presión en seno coronario en la regulación del volumen de retorno vía seno coronario. Consideraciones quirúrgicas en las técnicas de derivación atriopulmonar.

In order to find out the validity of the vascular waterfall mechanism in coronary venous circulation, the role of coronary sinus pressure in the regulation of coronary return volume via the coronary sinus is studied in healthy animals. An experimental model of pressure regulation in the coronary sinus was prepared, and aortic pressure, EKG and the cardiac output (measured by thermodilution) were recorded. The return volume via the coronary sinus was measured at coronary sinus pressure of 10 or less, 15, 20, and 25 mmHg or more, for a total of 36 determinations. Increased coronary sinus pressure did not produce significant changes in aortic pressure, heart rate, cardiac index or coronary return volume via coronary sinus. When coronary sinus pressure was 25 mmHg or more, there was a significant decline in the average of coronary return volume via coronary sinus. Nevertheless, stepwise variant regression showed that the coronary sinus pressure per se does not condition the volume of coronary return via the coronary sinus. Our results suggest that in the healthy animals, the vascular waterfall mechanism in coronary venous circulation is not valid. Our results suggest that in the correction of congenital cardiac malformations using atriopulmonary anastomosis procedures, employing techniques that ensure coronary sinus drainage into the left atrium, in order to avoid the hemodynamic repercussions attributable to the vascular waterfall mechanism, is not justified.

A new physiologic correction technique for re-establishment of pulmonary circulation. Experimental surgical development.

A new physiologic technique is presented for surgical correction of truncus arteriosus, pseudotruncus, transposition of the great arteries, double right ventricular outflow tract with subpulmonary ventricular septal defect and certain cases of Fallot's tetralogy. The basis of the technique are creation of a neo-right atrium, neo-pulmonary trunk, neo-right atrioventricular valve and a neo-pulmonary valve by right angular atriotomy and insertion of a homologous pericardial patch with a monocuspid valve. The pulmonary circulation is re-established by anastomosis of the neo-pulmonary trunk to the pulmonary tree. The technique was used on 26 mongrel dogs. In 14 the experiments were preliminary, to evaluate the technique's validity, and in the other 12 it was performed with extracorporeal circulation and the hemodynamic status was studied at 30 and 180 min postoperatively. The technique and its results and potential advantages are described. Clinical application is considered to be feasible.

Experimental evaluation of atriopulmonary anastomosis in the presence of high pulmonary resistance.

We studied pulmonary resistance as a surgical criterion for atriopulmonary shunt. We created a model of experimental pulmonary hypertension by establishing a systemic-pulmonary shunt in 11 dogs. Two to 3 months after the shunt operation, total pulmonary resistance was calculated before (7.24 +/- 1.54 U . m2) and after (3.50 +/- 1.54 U . m2) ligation of the shunt. An atriopulmonary anastomosis technique was then performed and the hemodynamic status of the dogs during the first 2 postoperative hours was evaluated. Pathologic study of the lungs disclosed no arterial lesions. From our experimental work, we conclude that the surgical criterion for establishing the indication for this operation should be pulmonary resistance, which is conditioned by the state of the intrapulmonary vessels. We propose a procedure for determining real pulmonary resistance in the course of preoperative catheterization.

Complete atrioventricular canal. Anatomic study and presentation of a new technique for total correction.

A new surgical technique for total correction of complete common atrioventricular canal was evolved from study of 34 specimens from affected infants who had died in the first year of life. An interventricular patch was fashioned to reconstruct the interventricular septum and the atrioventricular valves. The patch had two distinct components, one superior or atrial and the other inferior or ventricular. The division was made by inserting a lateral support at different levels on either face of the patch, to which the anterior and posterior atrioventricular cusps were sutured. The interatrial defect was closed with a patch that, together with the atrial component of the interventricular patch, produced a foramen ovale type closure mechanism. The authors present the pathologic observations which served as a basis for development of the surgical technique.

Extraatrial interatrial duct and reestablishment of aortopulmonary communication by enlarging the aortic arch. Experimental development of two surgical techniques for hypoplastic left heart syndrome palliation without extracorporeal circulation.

A new surgical procedure is presented for palliation of hypoplastic left heart syndrome. The first palliative technique consists of creation of an extraatrial interatrial duct and the second, reestablishment of the aortopulmonary communication by enlarging the aortic arch with a "conduit patch". Both procedures avoid having to clamp small systemic vessels and pulmonary veins and extracorporeal circulation is not needed. Extraatrial interatrial ducts were created in 10 dogs and the effectiveness of the procedure was evaluated. Reestablishment of the aorto-pulmonary communication and enlargement of the aortic arch was done in 7 specimens from patients with hypoplastic left heart syndrome who had died in the first hours of life and in 8 dogs. The surgical procedures, their advantages and the results obtained are described.

A new surgical technique for orthoterminal correction: experimental development.

A new technique is presented for surgical correction of tricuspid atresia, univentricular heart, pulmonary atresia with intact ventricular septum and hypoplastic ventricle, and hypoplastic left heart syndrome. The procedure consists of an angled right atriotomy, creation of an interatrial septal defect and a right neoatrium that is anastomosed to the pulmonary artery, and creation of a left neoatrium communicating with the left atrium through the interatrial septal defect. The technique was evaluated in 28 mongrel dogs. In 15 of these experimental procedures, the objective was to acquire skill in performing the technique. In the remaining 13, the procedure was executed with cardiopulmonary bypass. Hemodynamic studies were made at 30, 60, 120, and 180 minutes after operation. The results and advantages of the procedure are discussed. We consider it feasible for clinical application.