Pulmonary Stenosis: Causes, Symptoms, Diagnosis, Treatment

Pulmonary stenosis is the narrowing of the outflow tract of the right ventricle, causing an impediment to the flow of blood from the right ventricle into the pulmonary artery during systole.

Pulmonary stenosis is most often congenital and occurs mostly in children. Pulmonary stenosis may be valvular or directly subvalvular, localized in the outflow tract (subvalvular). Rareer causes include Noonan syndrome (a family syndrome similar to Turner's syndrome but without a chromosomal defect) and adult carcinoid syndrome.

Many children do not have clinical symptoms for many years. Such patients do not consult a doctor until adulthood. When the symptoms appear, they resemble aortic stenosis (fainting, angina, shortness of breath). Visible and palpable features reflect right ventricular (RV) hypertrophy and include visible swelling of the jugular veins (due to increased atrial contraction in response to hypertrophy of the prostate), precardial right ventricular protrusion (cardiac hump) and systolic jitter left of the sternum in the second intercostal space. With auscultation, I heart tone (S1) normal, II cardiac tone (S2) is split and elongated due to prolonged pulmonary expulsion [pulmonary component S3 (P) is delayed]. With insufficiency and hypertrophy of the right ventricle III and IV, cardiac tones (S3 and S4) are sometimes heard in the fourth intercostal space to the left of the sternum. It is believed that clicking with congenital pulmonary stenosis is a consequence of the pathological stress of the ventricular wall. A click appears in the early systole (very close to S2) and is not subject to hemodynamic changes. A rough accretion-decreasing ejection noise is best heard on the left of the sternum in the second (valve stenosis) or the fourth (subvalvular stenosis of the pulmonary trunk) intercostal space through the stethoscope with the diaphragm when the patient leans forward. In contrast to the noise of aortic stenosis, the noise of pulmonary stenosis does not radiate, and the growing component of noise is lengthened with progression of stenosis. The noise becomes louder when carrying out the Valsalva test and when inhaling; the patient must stand up for this phenomenon to become more audible.

Diagnosis is established using Doppler echocardiography, whose data can characterize stenosis as minimal (peak gradient <40 mmHg), moderate (41-79 mmHg), or severe (> 80 mmHg). ECG data always contribute to a partial assessment. They can be normal or reflect hypertrophy of the right ventricle or blockade of the right leg of the bundle. Right heart catheterization is prescribed only if there are suspicions of two levels of obstruction (valvular and subvalvular) when the clinical and echocardiographic results of the study differ, as well as before the surgery.

The prognosis without treatment is generally good and improves with adequate medical intervention. Treatment involves balloon valvuloplasty, prescribed to patients with manifestations of pulmonary stenosis and patients without clinical symptoms, with normal systolic function and a peak gradient> 40-50 mm Hg. Art.

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