Other Diseases of the Cardiac Valves

Pulmonary stenosis is almost always congenital. It will be discussed in chapter 10. Pulmonary regurgitation is rare. It occasionally develops in severe pulmonary hypertension, without intrinsic disease of the valve leaflets, when high pressure in the pulmonary artery makes the healthy pulmonary valve incompetent. Damage to the pulmonary valve may occur in infective endocarditis, found most frequently in intravenous drug abusers since bacteria introduced with intravenously administered drugs tend to infect right-sided cardiac valves.

Tricuspid stenosis is a rare complication of rheumatic fever. It almost always coexists with mitral-valve disease. Tricuspid regurgitation is a relatively common sequel to pulmonary hypertension. It commonly results in right ventricular failure, when the tricuspid orifice stretches, making the valve incompetent. Its presence merely aggravates the effect of right ventricular failure on the pressure

in the veins bringing blood to the right atrium. Tricuspid-valve repair or replacement is occasionally imperative, but physicians prefer to avoid it because operations on the tricuspid valve are not as effective as those performed on left-sided cardiac valves. Tricuspid-valve involvement may also occur in endocarditis among drug abusers.

Combined diseases of cardiac valves are a relatively common consequence of rheumatic fever involving the mitral and aortic valves. Aortic stenosis or regurgitation resulting from rheumatic fever is more frequent in combination with mitral-valve involvement (usually stenosis) than as the sole consequence of rheumatic fever. The course and prognosis of double valve disease usually follows the pattern of the predominant lesion.

Stenosis of the mitral or aortic valve may be associated with incompetence of the same valve. The consequences of combined stenosis and regurgitation of a left-sided cardiac valve usually differ little from those of pure stenosis; less commonly, however, they follow the pattern of pure regurgitation of the valve.