Porcine Model of the Arterial Switch Operation: Implications for Unique Strategies in the Management of Hypoplastic Left Ventricles

Abstract

There are no reports on the performance of the arterial switch operation (ASO) in a normal heart with normally related great vessels. The objective of this study was to determine whether the ASO could be performed in a healthy animal model. Cardiopulmonary bypass (CPB) and coronary translocation techniques were used to perform ASO in neonatal piglets or a staged ASO with prior main pulmonary artery (PA) banding. Primary ASO was performed in four neonatal piglets. Coronary translocation was effective with angiograms confirming patency. Piglets could not be weaned from CPB due to right ventricle (RV) dysfunction. To improve RV function for the ASO, nine piglets had PA banding. All survived the procedure. Post-banding RV pressure increased from a mean of 20.3 ± 2.2 mmHg to 36.5 ± 7.3 mmHg (p = 0.007). At 58 ± 1 days post-banding, piglets underwent cardiac MRIs revealing RV hypertrophy, and RV pressure overload with mildly reduced RV function. Catheterization confirmed RV systolic pressures of 84.0 ± 6.7 mmHg with LV systolic pressure 83.3 ± 6.7 mmHg (p = 0.43). The remaining five PA banded piglets underwent ASO at 51 ± 0 days post-banding. Three of five were weaned from bypass with patent coronary arteries and adequate RV function. We were able to successfully perform an arterial switch with documented patent coronary arteries on standard anatomy great vessels in a healthy animal model. To our knowledge this is the first time this procedure has been successfully performed. The model may have implications for studying the failing systemic RV, and may support a novel approach for management of borderline, pulsatile left ventricles.

A Multi-omic and Multi-Species Analysis of Right Ventricular Failure

“…Four ( n =4) pigs of similar age and weight were housed at the University of Minnesota Research Animal Resources facility for 8 weeks and these animals served as controls. Animals were anesthetized and underwent pulmonary artery banding (PAB) surgical procedure using an approach previously described(12). The main pulmonary artery was accessed via a left thoracotomy and an umbilical tape looped around the vessel and cinched until the peak systolic pressure in the right ventricle increased to two-thirds of peak systemic pressure, or approximately 30-40 mmHg.…”

“…Cardiac MRI: We previously described our large animal cardiac MRI protocol (12). Briefly, all studies were performed on a Siemens Aera 1.5T (Siemens, Malvern, PA, USA) scanner.…”

Establishing Background Pathologic Changes of Valve Replacement Surgery in Sheep

“…CPB was initiated and when adequate return to the venous reservoir was established, the animal was cooled to approximately 28 °C a standard practice common in heart valve replacement surgeries in large animals. 1 , 6 , 10 A small stab incision was made through the center of a previously placed purse string in the left ventricular apex and an appropriately sized venous cannula was positioned within the left ventricle. Venting was established immediately at low flow.…”