Heparin-coated shunts for lesions of the descending thoracic aorta. Experimental and clinical observations.

Heparin sodium-coated shunts are employed frequently to maintain trunk and lower extremity perfusion during temporary occlusion of the descending thoracic aorta. In the past five years, this shunt has been used in a series of 39 patients ranging in age from 19 to 72 years old, with 34 survivors (87%). The proximal end of the shunt was placed in the subclavian artery in 17 patients, the left ventricle in ten, and in the ascending or transverse aortic arch in 12. The distal end of the shunt was placed either in the lower thoracic aorta or in the femoral artery. For further evaluation of effectiveness, paired observations were made in dogs to determine the physiological consequences with the proximal end of the shunt inserted at two different sites. Although neither shunt decompressed the left ventricle fully, the subclavian-femoral shunt was significantly more effective than was the left ventricle-femoral artery bypass. If a choice exists for sites of insertion of the shunt, it appears that it should be placed distal to the aortic valve, since this position provides the least increase in systolic blood pressure and is associated with a lower demand for myocardial blood flow.