Dissection of the aneurysm is the most dangerous step during graft replacement of the descending thoracic aorta. Sudden hemorrhage may follow wall rupture or disruption of major collaterals before the aorta can be clamped. A simple modification of the classic Gott is illustrated, which makes the shunt work also as a partial bypass if needed, with rapid reinfusion of blood losses. Nineteen of 25 patients requiring resection of descending aortic aneurysms from 1982 to 1990 were treated with this method with no mortality.