Pulmonary Valve Stenosis

Pulmonary valve stenosis is a fixed narrowing at the pulmonary valve that impedes blood leaving the right ventricle for the pulmonary artery. The right ventricle must generate higher systolic pressure to move blood through the narrowed opening. Over time, this pressure load produces concentric right ventricular hypertrophy. A compensated patient may have no symptoms for years. Sustained severe obstruction eventually makes the hypertrophied ventricle stiff during diastole. Filling becomes less efficient, tricuspid regurgitation may worsen, and the right ventricle can dilate and fail. The resulting findings are systemic venous congestion—elevated jugular venous pressure, hepatomegaly, ascites, and peripheral edema—rather than the pulmonary crackles that more strongly suggest left-sided failure. In a neonate with critical obstruction, very little blood reaches the lungs through the stenotic valve. Pulmonary blood flow depends on the ductus arteriosus. Blood may cross the patent foramen ovale from right to left, bypassing the lungs and producing cyanosis. This is why a critically ill cyanotic neonate with pulmonary stenosis requires a different first response from a stable older child or adult. The usual examination pattern is a harsh systolic...