Failure to reduce the size of experimentally produced myocardial infarcts by cortisone treatment.

Cortisone, whether used prophylactically or therapeutically, did not appear to have any beneficial effect in reducing the size of the mvocardial infarcts produced by coronary artery ligation in dogs. No significant differences were noted between the control and cortisone-treated animals in respect to the vascularity of the infarcted area or the rate of healing.stein reported recently that cortisone reduces the area of residual fibrosis resulting from experimental acute coronary occlu-sion.' Since the need for a method of reducing the size of myocardial infarcts is well recognized this report received much attention even prior to publication in this journal. Unfortunately, the result of similar experiments to be detailed here fail to confirm the claims made by Johnson and co-workers. PROCEDURE Two series of experiments were performed. In the first series 8 of 15 dogs were treated daily with 10 mg. per kilogram of cortisone acetate subcu-taneously, starting six days prior to ligation of the left anterior ramus descendens coronary artery. The remaining seven dogs were operated upon but received no cortisone treatment. The coronary arteries were ligated via a conservative intercostal approach by the two-stage technic of Harris2 at sites varying from 10 to 33 mm. from the point of origin of the artery. The cortisone injections were continued throughout the experiment, and each experiment terminated at the time indicated in table 1. Observations were made relative to the nature and amount of pleural and pericardial adhesions, the external appearance of the hearts, and the size of the in-farcts as revealed by serial sectioning of the fresh specimens. Sections were taken for microscopic examination after suitable fixation in formalin. After learning that our cortisone dosage was much higher than that used by the Detroit group' a second series of experiments was undertaken which followed their design except where more physiologic pro-From the Merck Institute for Therapeutic Research , Rahway, N. J. 544 cedures seemed desirable. Fourteen dogs were subjected to standardized ligation of the ramus de-scendens artery. The arteries were ligated by the two-stage technic at the point where the posterior margin of the left atrial appendage overlies the vessel. This corresponds roughly to the "high liga-tion" described by Johnson and associates.' Seven dogs received an intramuscular injection of 3 mg. per kilogram of cortisone acetate at the precise moment of complete occlusion of the artery and daily thereafter for the duration of the experiment. The remaining seven dogs were untreated. …