Definition:—A condition of the aortic orifice in which, through the influence of disease, the lumen of the aorta has become narrowed—reduced in size—or constricted, resulting in a permanent obstruction to the flow of the blood from the ventricle. The condition is one of much importance and is evidenced by a murmur, which occurs at the time of systole, and which is usually followed b/ a characteristic regurgitant murmur. It must be borne in mind, however, that a systolic murmur may occur at other times and from other causes, such as aneurysm or calcareous deposits on the walls of the aorta. If incompetency of the aortic valves is not apparent at the time of the diagnosis of the aortic stenosis, it will soon follow, with unmistakable evidences. This condition seldom follows aortic insufficiency.
Etiology:—While the condition occurs more commonly among men who are advanced in years, because in these atheromatous changes are more apt to occur, it is not uncommon in individuals of either sex and in middle life, and cases occasionally occur in which the condition is thought to have been congenital; however, this may have resulted from a masked or latent form of rheumatism, as this latter disease by inducing endocarditis, is a frequent cause of stenosis at any time of life, from thickening and adhesion of the covering membranes. There is, however, a slow development of stenosis, which occurs from calcareous deposits referred to. Granulations, fibrous thickening and other structural changes and the deposit of vegetations, will each, or all combined, result in the narrowing of the lumen of this important orifice. The condition usually includes changes in the structure of the walls of the aorta, and these changes later, extend to the valves. It is therefore rare that the condition is a simple one. It is almost invariably complex in its character.
Symptomatology:—The pulse beat in aortic stenosis is usually normal. Occasionally it is slow, regular and not readily compressible, but small; very seldom, if ever, frequent. This corresponds with the heart effort, which is also slow, labored and forceful, sometimes heaving in the advanced cases; however, where there is much dilatation it is apt to be enfeebled. With these conditions, after the disease is well established, there is headache, vertigo, syncope and often extreme paleness of the countenance. This latter condition may be a constant one, from anemia, which occurs very soon, as a result of the failure in the proper oxygenation of the blood.
It must be borne in mind that the condition may exist quite a long time, perhaps some years, before many symptoms appear; this is due to the fact that compensatory hypertrophy is sufficient. When this is no longer the case, the evidences of impaired circulation are soon apparent, often abruptly so. As the condition progresses, mild dropsical symptoms will occur, such as edema of the face or of the feet, but general dropsy is not common.
Prognosis:—If this condition can be correctly diagnosed early, and the patient will follow advice as to habits of life and eating, it can be considered a less unfavorable lesion than perhaps any other valvular disease. The fact, also, that there is advanced atheroma in old men of previously good habits is not necessarily a serious condition, but if there has been dissipation, especially the extreme use of alcohol, and luxurious habits of living, the outlook is much less favorable. In patients of middle life, where the condition is due to fibrinous changes or to the result of severe inflammation, the outlook is much less favorable.