A reappraisal of the mechanical factors associated with aortic insufficiency has led to a clearer delineation of the surgical procedures. The anatomic lesions of endocarditis, congenital lesions, aneurysms of the sinus of Valsalva and aortic root, dissecting aneurysms, and others are widely divergent; in most cases, valve cusps are involved. Surgical correction has been achieved with anatomically shaped synthetic cusps or total valves to replace the destroyed valvular tissue. They have been sutured into the normal anatomic position to achieve complete control of the insufficiency. Cardiac arrest has been induced and maintained during the operations by local cardiac cooling for periods ranging from 20 minutes to 2 hours. The results have been highly encouraging.