Its most frequent cause is acute exudative and interstitial rheumatic endocarditis. The origin of nearly all valvular disease may be traced back to an attack of rheumatic fever. Next to acute rheumatism, chorea is its most frequent cause. Bright's disease and pyæmia may cause it, and atheroma or arteritis deformans extending to the valves will give rise to valvular lesions which cause obstruction.
Any of the conditions that cause acute exudative and interstitial endocarditis may effect changes in the valves, and the tissue thus developed, undergoing atheromatous, fatty, fibroid, calcareous, or connective-tissue change, will cause obstruction.
Increased tension of the aorta may be the result of chronic spinal deformity, and may be regarded as the indirect cause of aortic stenosis.
The connection between cancer and cardiac valvular disease is to be noticed, if not as cause and effect, at least as a remarkable and noteworthy coincidence.
Women are far less subject to aortic obstruction after rheumatism than men. In men the aortic valves are subject to more pressure and strain than in women, and hence non-rheumatic disease of these valves is very common, while in women it is very rare.
Aortic disease especially occurs in men whose occupations involve repeated, sudden, and great muscular effort.
In old age the walls of the aorta are weakened, and when aortic disease is met with in young subjects it must be regarded as the result of a premature senile condition of the vessels. Allbutt says that in Leeds quite young men have aortic valvular disease, and Peacock mentions several cases where the disease has occurred in young girls who have been placed at service before they were fully developed.
Sometimes the valves are found to be studded with vegetations, apparently of syphilitic origin. Corvisart and Virchow both admit the possibility of such an origin for valvular disease of the heart, but no unquestionable case has as yet been advanced in proof of it. It has been claimed that this is the reason why soldiers so frequently suffer from heart disease; but sailors are notoriously more subject to syphilis than soldiers, and heart disease is rare among them.
The reason is evidently to be found in their mode of dress: sailors wear loose clothes, soldiers have the tightest possible fitting garments. More force is required to pump the blood through the constricted vessels, hence arises more strain on the aorta and more strain on the valves.
Single, sudden muscular efforts have in a limited number of cases produced disease at the aortic orifice.