Other meanings of Pulmonary valve stenosis
Cardiology
Pulmonary valve stenosis is a heart condition characterized by narrowing of the pulmonary valve, which obstructs blood flow from the right ventricle to the pulmonary artery. This obstruction increases pressure in the right ventricle and can lead to right ventricular hypertrophy and, if severe, heart failure. The condition may be congenital or acquired, with severity ranging from mild to critical. Pulmonary valve stenosis is one of the most common congenital heart defects, accounting for approximately 8–10% of all congenital heart disease cases.
The primary defect is a narrowing at the valvular level, often due to a dome-shaped valve with fused commissures, but it can also be subvalvular (infundibular) or supravalvular. In congenital cases, the valve may be dysplastic, with thickened, immobile leaflets, as seen in Noonan syndrome. Acquired causes include rheumatic heart disease and carcinoid syndrome, though these are rare in developed countries. The obstruction increases right ventricular afterload, leading to concentric hypertrophy, reduced compliance, and eventually diastolic dysfunction. In severe neonatal cases, critical pulmonary stenosis can cause right-to-left shunting through a patent foramen ovale, resulting in cyanosis.
Mild stenosis is often asymptomatic and discovered incidentally on physical examination. Typical findings include a systolic ejection murmur at the left upper sternal border, radiating to the back, and a palpable right ventricular heave. Severe stenosis may present with exertional dyspnea, fatigue, syncope, or chest pain. In infants with critical stenosis, symptoms include cyanosis and heart failure. Diagnosis is confirmed by echocardiography, which assesses valve morphology, Doppler peak gradient, and right ventricular size and function. Cardiac catheterization is reserved for cases where intervention is planned or when echocardiography is inconclusive. Electrocardiography may show right axis deviation and right ventricular hypertrophy.
Asymptomatic patients with mild or moderate stenosis (peak gradient <64 mmHg) are managed conservatively with regular follow-up. For symptomatic patients or those with severe stenosis, balloon pulmonary valvuloplasty is the first-line intervention, with success rates exceeding 90% in typical valvular stenosis. Surgical valvotomy or valve replacement is reserved for dysplastic valves, subvalvular or supravalvular stenosis, or failed balloon procedures. Long-term outcomes are excellent for mild to moderate cases, with survival similar to the general population. However, patients may develop pulmonary regurgitation after intervention, requiring lifelong surveillance. Pregnancy is generally well tolerated in mild cases but carries increased risk in severe untreated stenosis.
Pulmonary valve stenosis is a component of several genetic syndromes, including Noonan syndrome, where the valve is often dysplastic and responds poorly to balloon valvuloplasty. It also occurs in association with congenital rubella infection and in Alagille syndrome. In rare cases, acquired pulmonary stenosis can result from extrinsic compression by mediastinal tumors or aortic aneurysms. Historical treatment began with closed transventricular valvotomy in 1948, pioneered by Russell Brock, before the advent of cardiopulmonary bypass. The first successful balloon valvuloplasty was performed in 1982 by Jean Kan, revolutionizing management. In developing countries, rheumatic pulmonary stenosis remains a rare but recognized entity, often coexisting with mitral valve disease. Additionally, mild pulmonary stenosis is a common finding in patients with Noonan syndrome and may be mistaken for an innocent murmur in infancy.
This article focuses on pulmonary valve stenosis as a distinct clinical entity, not to be confused with subvalvular or supravalvular stenosis, which have different etiologies and management.
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