Pulmonary regurgitation
Aetiology
Numerous conditions can cause pulmonary regurgitation (PR). It can be caused by either a disease of the pulmonic valve or secondary to pulmonary hypertension.
A table of common causes is provided below (Image 1).
Clinical manifestation
Isolated PR causes right ventricular (RV) volume overload and may be tolerated for many years without difficulty unless it complicates.
In most patients, clinical manifestations of the primary disease usually overshadow the PR, which often results only in incidental auscultatory findings.
With the disease progression the patient may report:
- fatigue
- exertional dyspnea
- abdominal fullness or bloating
- lower extremity swelling
If the PR is secondary to pulmonary hypertension, the clinical picture is dominated by the primary lung disease or the high pulmonary vascular resistance rather than the volume load.
Auscultation
A diastolic low pitched murmur can be heard best at the third and fourth left intercostal spaces adjacent to the sternum. A Graham Steell murmur occurs when pulmonary artery pressure exceeds approximately 55 mm Hg and is high-pitched, blowing, and decrescendo, beginning immediately after P2, and is most prominent in the left parasternal region in the second to fourth intercostal spaces.
ECHO diagnosis
A slight amount of PR has been reported in 40–78% of patients with normal pulmonary valves.
TTE, TOE, or 3D echo could provide useful information regarding anomalies of cusp number (bicuspid or quadricuspid valves), motion (doming or prolapse), or structure (hypoplasia, dysplasia, absence of pulmonary valve).
The evaluation of the pulmonary valve anatomy is, however, more difficult than for other valves (limited by poor acoustic access).
In adults, visualisation of the pulmonary valve is obtained from the parasternal short-axis view at the level of the aortic valve or from a subcostal approach.
With more severe degrees, two-dimensional echocardiography shows RV dilation and, in patients with pulmonary hypertension, RV hypertrophy as well. RV function can be evaluated. Abnormal motion of the septum characteristic of volume overload of the right ventricle in diastole and septal flutter may be evident. The motion of the pulmonic valve may point to the cause of the PR.
1) Severity of PR
Colour flow imaging is used to diagnose PR by documenting a diastolic jet in the RV outflow tract directed towards the RV.
Pathological PR is distinguished from physiological PR by a longer duration of flow (holodiastolic) and a wider jet as the regurgitant jet crosses the pulmonic valve. Functional PR jets are usually very small, central, and spindle shaped.
In severe PR, where equalisation of the diastolic pulmonary artery and RV pressures occurs earlier in diastole, the colour jet area can be brief and inaccurate (dependency on the driving pressure). The assessment of PR severity is usually estimated by the diameter of the jet at its origin.
The maximum colour jet diameter (width) is measured in diastole immediately below the pulmonic valve (at the junction of the RV outflow tract and pulmonary annulus) in the parasternal short-axis view or from the subcostal view.
Although this measurement suffers from a high inter-observer variability, a jet width that occupies >50–65% of the RV outflow tract width measured in the same frame suggests severe PR. Additionally, reversal of colour Doppler flow in pulmonary arteries is a very specific sign of severe PR.
Limitations
Grading of the severity of PR is limited and some methods used to grade aortic regurgitation have not been validated for the use in PR. These include the flow convergence method, pulsed Doppler and continuous wave Doppler.
Image 2 Grading ot PR severity
Lancellotti P, Tribouilloy C, Hagendorff A, et al. Scientific Document Committee of the European Association of Cardiovascular Imaging. Recommendations for the echocardiographic assessment of native valvular regurgitation: an executive summary from the European Association of Cardiovascular Imaging. Eur Heart J Cardiovasc Imaging. 2013 Jul;14(7):611-44.
Video 1 Mild PR, subcostal view with Colour Doppler - regurgitant jet is seen inside the RVOT
Video 2 Moderate PR, PSAX view with Colour Doppler - large regurgitant jet in RVOT
Image 3 CW Doppler of PR jet, Moderate PR
Image 4 Vena contracta (VC) measurement, moderate PR - diameter of the narrowest part of the regurgitant jet at the level of the pulmonic valve is measured, VC is 0,4 cm.
Video 3 Massive PR in a patient with correction of Tetralogy of Fallot, Colour Doppler - a large regurgitant jet is visualized
Image 5 CW Doppler measurement at the level of pulmonic valve, massive PR - note the dense signal and triangular waveform of the CW PR jet with steep acceleration and deceleration
Other diagnostic methods
Cardiac magnetic resonance may be used to assess pulmonic valve anatomy, recognise any obstruction above or below the valve, measure pulmonary artery dilation, and quantify PR severity.
Management
Treatment of the primary condition is the most crucial aspect of management. Eliminating the primary cause of PR can lead to improvement of the PR.
Symptomatic patients who are not surgical candidates receive management with heart failure therapy, especially diuretics, ACE inhibitors, and digoxin.
1) Surgery
Surgery is indicated in severe symptomatic PR or in asymptomatic severe PR with two out of four of the following conditions:
- elevated right ventricular volume (end-diastolic vol. index more than 160 mL/m2 or end-systolic volume index of 80 ml/m2)
- elevated right ventricular pressure
- reduced exercise tolerance
- mild to moderate systolic dysfunction of either right or left ventricle
In case of surgery a bioprosthetic valve is preferable to a mechanical valve as long-term anticoagulation is not required and has better longevity (up to 15 years).
Patients with iatrogenic PR caused by the surgical correction of tetralogy of Fallot (TOF) might benefit from pulmonary valve replacement, preferably with a porcine bioprosthesis or a pulmonary allograft.
2) Transcatheter therapy
In addition to surgery, the transcatheter pulmonary valve replacement is being implemented with great success in native pulmonic valve disease and PR following surgical correction of congenital heart defects.
The Melody Transcatheter Pulmonary Valve (also known as a “Melody valve”) is a replacement pulmonary heart valve (Image 6).
TPV Systems - Melody TPV Ensemble II Delivery System | Medtronic
References
- https://www.statpearls.com/ArticleLibrary/viewarticle/28063
- Ruckdeschel E, Kim YY Pulmonary valve stenosis in the adult patient: pathophysiology, diagnosis and management Heart 2019;105:414-422.
- Zipes, Peter Libby, Robert O. Bonow ; founding editor and online editor Eugene Braunwald. Braunwald's Heart Disease : a Textbook of Cardiovascular Medicine. Philadelphia, PA :Elsevier/Saunders, 2015
- Patrizio Lancellotti, Christophe Tribouilloy, Andreas Hagendorff, Bogdan A. Popescu, Thor Edvardsen, Luc A. Pierard, Luigi Badano, Jose L. Zamorano, On behalf of the Scientific Document Committee of the European Association of Cardiovascular Imaging: Thor Edvardsen, Oliver Bruder, Bernard Cosyns, Erwan Donal, Raluca Dulgheru, Maurizio Galderisi, Patrizio Lancellotti, Denisa Muraru, Koen Nieman, Rosa Sicari, Document reviewers: Erwan Donal, Kristina Haugaa, Giovanni La Canna, Julien Magne, Edyta Plonska, Recommendations for the echocardiographic assessment of native valvular regurgitation: an executive summary from the European Association of Cardiovascular Imaging, European Heart Journal - Cardiovascular Imaging, Volume 14, Issue 7, July 2013, Pages 611–644, https://doi.org/10.1093/ehjci/jet105
