L. Bernstein

We report a technique for the enlargement of a hypoplastic aortic root by an operation whereby the hypoplastic aortic root has been so enlarged by the insertion of a Dacron fabric gusset that it will accommodate a size 9A or larger Starr-Edwards prosthesis. Our experience in five patients is described. No matter what type of valve is used for replacement of a diseased aortic valve, and no matter what improved designs of valvular prosthesis are ultimately developed, it will be necessary (in the particular group described) to enlarge the aortic ring to accommodate a size which will function correctly without causing left ventricular outflow obstruction.

The pharmacodynamics of nitroglycerin have been studied in dogs and man. In dogs, intravenous nitroglycerin (TNG) caused a decrease in left ventricular work, myocardial blood flow (MFB), and myocardial oxygen consumption, and no significant change in coronary vascular resistance. Intracoronary artery TNG in dogs caused an immediate increase in MBF and a decrease in coronary vascular resistance that persisted until arterial pressure fell. In man, sublingual TNG (0.4 mg.) caused a decrease in left ventricular work, MBF, and myocardial oxygen consumption, and no significant decrease in coronary vascular resistance in patients with and without arteriographically proven coronary artery disease. The injection of doses of 0.1 to 0.2 mg. of TNG directly into the coronary artery in man caused an immediate increase in MBF and a decrease in coronary vascular resistance in patients with and without arteriographically proven coronary artery disease. The hypothesis proposed for the mechanism of action of TNG in the relief of angina pectoris is first, a decrease in coronary vascular resistance due to its effect on the coronary circulation, and, secondly, a decrease in cardiac work due to its effect on the systemic circulation.