False aneurysm formation: a complication following the modified Blalock-Taussig shunt

False aneurysm formation is a rare complication of the modified Blalock-Taussig shunt. A patient is described in whom this complication arose 11 months after operation. Death resulted from rupture of the aneurysm into the right lung with associated massive hemoptysis. The onset of hemoptysis in patients with a functioning modified Blalock-Taussig shunt may be the first evidence of a developing false aneurysm.