Apico-aortic shunt: a support technique during surgery on the descending thoracic aorta

To find out whether apico-aortic shunt may become an alternative support technique during surgery on the descending thoracic aorta, performance between apico-aortic shunt and aorto-aortic shunt was compared. In 5 sheep weighing 20-25 kg, apico-aortic shunt and aorto-aortic shunt were instituted with covalently bonded heparin coated polyvinyl tube (internal diameter 5 mm). After clamping the descending thoracic aorta, apico-aortic shunt and aorto-aortic shunt were opened for 30 minutes each. Proximal pressure was elevated to 200 mmHg and distal pressure was fallen to 55 mmHg after clamping the descending thoracic aorta. Opening of apico-aortic shunt and aorto-aortic shunt decreased proximal pressure to 178 +/- 14.8 and 173 +/- 12.0 mmHg, respectively (p = 0.57), and raised distal pressure to 82.4 +/- 7.8 and 90.0 +/- 3.5 mmHg, respectively (p = 0.83). The baseline blood flow of the descending thoracic aorta was 1.4-1.5 l/min. Apico-aortic shunt and aorto-aortic shunt were 0.76 +/- 0.16 and 0.80 +/- 0.22 l/min, respectively (p = 0.67). Blood gas tension, pH and BE measurement showed no significant change and difference between apico-aortic shunt and aorto-aortic shunt, and before and after clamping the descending thoracic aorta. Using apico-aortic shunt, interposition of bioprosthetic valved conduit in the descending thoracic aorta in 10 sheep was successfully performed without paraplegia and any other complications. We concluded that apico-aortic shunt may become an alternative support technique during surgery on the descending thoracic aorta in some specific situations.