Grading of severity of pulmonary stenosis by Doppler echocardiography

Grading of severity of pulmonary stenosis by Doppler echocardiography

Pressure gradient across the pulmonary valve is estimated from the continuous wave Doppler derived velocity across the pulmonary valve using the simplified Bernoulli equation: Pressure gradient = 4V². Sample volume of Doppler has to be aligned parallel to the flow, guided by colour Doppler imaging in the parasternal short axis view. Subcostal view may be better in children. Highest value obtained from multiple views should be used [1]. Doppler derived gradient has good correlation with cath derived gradient [2]. It should be remembered that Doppler measures peak instantaneous gradient while cath measures peak to peak gradient [3].

Grading of severity is based on peak jet velocity and the corresponding gradient. Severe pulmonary stenosis is defined as peak jet velocity more than 4 m/s and peak gradient of more than 64 mm Hg. Moderate pulmonary stenosis has a peak jet velocity between 3-4 m/s and peak gradient between 36-64 mm Hg. Mild pulmonary stenosis has a peak velocity less than 3 m/s and peak gradient less than 36 mm Hg [4]. But this grading does not mention the minimum gradient required for the diagnosis of mild pulmonary stenosis!

References

1. Frantz EG, Silverman NH. Doppler ultrasound evaluation of valvar pulmonary stenosis from multiple transducer positions in children requiring pulmonary valvuloplasty. Am J Cardiol. 1988 Apr 1;61(10):844-9. doi: 10.1016/0002-9149(88)91077-6. PMID: 3354449.
2. Lima CO, Sahn DJ, Valdes-Cruz LM, Goldberg SJ, Barron JV, Allen HD, Grenadier E. Noninvasive prediction of transvalvular pressure gradient in patients with pulmonary stenosis by quantitative two-dimensional echocardiographic Doppler studies. Circulation. 1983 Apr;67(4):866-71. doi: 10.1161/01.cir.67.4.866. PMID: 6825241.
3. Aldousany AW, DiSessa TG, Dubois R, Alpert BS, Willey ES, Birnbaum SE. Doppler estimation of pressure gradient in pulmonary stenosis: maximal instantaneous vs peak-to-peak, vs mean catheter gradient. Pediatr Cardiol. 1989 Summer;10(3):145-9. doi: 10.1007/BF02081678. PMID: 2798190.
4. Baumgartner H, Hung J, Bermejo J, Chambers JB, Evangelista A, Griffin BP, Iung B, Otto CM, Pellikka PA, Quiñones M; EAE/ASE. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. Eur J Echocardiogr. 2009 Jan;10(1):1-25. doi: 10.1093/ejechocard/jen303. Epub 2008 Dec 8. Erratum in: Eur J Echocardiogr. 2009 May;10(3):479. PMID: 19065003.