Coronary involvement in dissecting aneurysm of the aorta.

Although there are many reports of cases of dissecting aneurysm of the aorta, the number with involvement of the coronary arteries, either deduced from electrocardiographic change or discovered at death, is not great. Shennan (1934) makes no mention of these in his monograph. Also, in the few examples that have been recorded, little attention has been paid to the exact mode of interference with the coronary blood supply. The problem is not without clinical interest, as cases of dissecting aortic aneurysm with long survival are well known. Graham (1886) is usually considered to have recorded the longest period of survival, his patient living for more than thirty years; but the date of formation of the aneurysm is assumed by him to be that on which an internal injury was. sustained. Even after involvement of the coronary arteries the patient may survive for many months. From a study of the autopsy reports it is apparent that there are several ways in which the coronary blood supply can be rendered inadequate. First, the coronary arteries can be involved in the aortic dissection, which may merely occlude their mouths, or actually extend into and along their walls. Secondly, they can be compressed, either by extravasated blood from the leaking aneurysm, or by the blood of a hlmopericardium. It has been claimed that this blood may distend the pericardial sac, thereby compressing the coronary arteries, or give rise to the formation of percardial adhesions which subsequently exert traction. Thirdly, cases are recorded with cardiographic changes of the type met with in coronary ischlmia, yet without obvious involvement of the coronary arteries. These changes have been considered to result from deficient coronary filling, due to the fall in blood pressure associated with massive himorrhage frotn the dissecting aneurysm. Finally, because atheroma is common in patients with dissecting aneurysm, it is also to be expected that coronary occlusion will, at times, be an incidental event independent of the dissection. We record below a case showing cardiographic changes in which both coronary arteries were surrounded by extravasated blood derived from the aneurysm.