Pulmonary Valvar Stenosis

16 Pulmonary Valvar Stenosis


With Christian J. Kellenberger


Definition and Classification



  • image Pulmonary valvar stenosis occurs with a reduced orifice of the pulmonary valve due to fusion of the thickened valve leaflets. The valve can also be bicuspid and have a hypoplastic annulus. Stenosis of the dysplastic valve is typically seen in Noonan syndrome.
  • image Isolated or associated with subvalvar, supravalvar, or peripheral branch pulmonary artery stenosis
  • image Critical pulmonary stenosis refers to obstruction resulting in suprasystemic right ventricular systolic pressures, tricuspid regurgitation, and a right-to-left shunt across the atrial septum, and often pulmonary circulation is dependent on the flow through the ductus arteriosus.

Pathophysiology



  • image Increased impedance to right ventricular outflow requires increased right ventricular pressure to maintain pulmonary circulation.
  • image Increasing pressure results in concentric hypertrophy of the right ventricle and loss of compliance with impaired diastolic filling.
  • image Systolic pressure in the right ventricle and degree of hypertrophy are proportional to the degree of obstruction in the absence of heart failure.
  • image Severity of the lesion is generally classified according to the right ventricular systolic pressure.
  • image Less severe obstruction is well tolerated with gradual hypertrophy and dilatation of the right ventricle and preserved right ventricular function.
  • image More severe obstruction leads to suprasystemic right ventricular pressures, moderate dilatation of the right ventricle, and right heart failure.
  • image Right atrium may also become hypertrophied and dilated with tricuspid valve regurgitation.
  • image Increasing right atrial pressures leads to right-to-left shunting at atrial level if foramen ovale is patent or an atrial defect is present.

Clinical Manifestations

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Jan 14, 2016 | Posted by in RESPIRATORY IMAGING | Comments Off on Pulmonary Valvar Stenosis

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