Pulmonary stenosis

Two-dimensional echocardiography with Doppler assessment

Severity of right ventricular outflow tract (RVOT) obstruction is defined as follows:​[15]European Society of Cardiology. 2020 ESC guidelines for the management of adult congenital heart disease (previously grown-up congenital heart disease). Aug 2020 [internet publication]. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Grown-Up-Congenital-Heart-Disease-Management-of ​

• Mild: peak gradient is <36 mmHg and peak velocity is <3 m/s

• Moderate: peak gradient is 36-64 mmHg and peak velocity is 3-4 m/s

• Severe: peak gradient is >64 mmHg and peak velocity is >4 m/s; mean gradient is >35 mmHg.

Critical pulmonary stenosis may occur in neonates if the RVOT obstruction caused by the stenotic valve is so severe that it leads to cyanosis. The major source of pulmonary blood flow in severely obstructed patients is through the ductus arteriosus. Once the ductus arteriosus begins to close, blood flow will be insufficient and the neonate will become hypoxemic.[9]Latson LA. Critical pulmonary stenosis. J Interv Cardiol. 2001 Jun;14(3):345-50. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1540-8183.2001.tb00343.x?sid=nlm%3Apubmed http://www.ncbi.nlm.nih.gov/pubmed/12053395?tool=bestpractice.com