Pulmonary valve regurgitation, also known as pulmonary valve insufficiency or pulmonary valve incompetence, is a valvulopathy that describes leaking of the pulmonary valve diastole that causes blood to flow in the reverse direction from the pulmonary trunk and into the right ventricle.
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Epidemiology
Prevalence of pulmonary regurgitation is thought to have two demographical peaks, firstly in young patients with repaired congenital pulmonary stenosis or right ventricular outflow tract obstruction repairs, or secondly in patients with pulmonary arterial hypertension 1. As such, given the multitude of causes, the exact prevalence is difficult to determine.
Clinical presentation
Clinical features can vary dependent on the severity of the pulmonary regurgitation, and often only manifest when pulmonary regurgitation is severe 1,2. When symptomatic, it eventually leads to right-predominant clinical features of heart failure 1,2. Depending on the etiology, patients may have clinical features of pulmonary hypertension 1,2.
Clinical examination classically reveals a right ventricular heave on praecordial palpation and an early diastolic murmur that is heard on praecordial auscultation known as the Graham Steell murmur 1-3. Occasionally the murmur heard may be holodiastolic, reflecting increased disease severity 1,2.
Pathology
The characteristic hemodynamic feature of severe pulmonary regurgitation, similarly to the effect of aortic regurgitation on the left side of the heart, is an enlargement of the right ventricle in response to right ventricular overload and an effort to maintain cardiac output 1,2. This results in right ventricular dysfunction, explaining the clinical features of this valvulopathy, and functional tricuspid regurgitation 1,2. At this point, there is also a decrease in the cardiac output 1,2.
Etiology
Etiologies of pulmonary regurgitation can be considered primary, where there is valvular pathology, or secondary ('functional'), where there is dilation of the annulus as a result of pulmonary arterial hypertension or pulmonary artery dilation 1,2. Overall, secondary pulmonary regurgitation is more common than primary pulmonary regurgitation 1,2.
Primary causes include 1,2,4,5:
- iatrogenic (most common primary cause)
- surgical treatment of congenital pulmonary stenosis
- surgical treatment of tetralogy of Fallot
- infective endocarditis
- carcinoid heart disease (often alongside pulmonary stenosis)
- rheumatic heart disease
- congenital pulmonary regurgitation
Disorders leading to secondary (functional) pulmonary regurgitation include 1,2,4,5:
- any cause of pulmonary arterial hypertension (see individual article for an in-depth discussion)
- pulmonary artery dilation
Radiographic features
Plain radiograph
Signs of pulmonary regurgitation on chest radiograph are often subtle, but include 1:
- right ventricular enlargement
- prominent pulmonary trunk
- features of tricuspid regurgitation may also be present
- features of congestive heart failure may also be present
Ultrasound: echocardiography
Echocardiography is useful for evaluating the cause of pulmonary regurgitation, for assessing the regurgitant volume, and for assessing the right-sided cardiac chambers 4. The echocardiographic detection of minor or trivial pulmonary regurgitation is common and present in up to 78% of people 4.
For pathological pulmonary regurgitation, various parameters are used in order to determine severity, such as 4:
- mild
- pulmonary valve normal
- right ventricular size normal
- central jet thin
- jet density soft
- jet deceleration slow
- pulmonary systolic flow compared to systemic flow slightly increased
- moderate
- pulmonary valve may be normal or abnormal
- right ventricular size may be normal or abnormal
- central jet intermediate
- jet density dense
- jet deceleration variable
- pulmonary systolic flow compared to systemic flow intermediate
- severe
- abnormal valve morphology
- right ventricular dilation
- jet width exceeding 70% of the annular diameter
- dense spectral envelope with a pressure half time < 100 ms
- steep jet deceleration with deceleration time < 260 ms
- pulmonary systolic flow compared to systemic flow greatly increased
- regurgitant fraction > 40%
- diastolic flow reversal within pulmonary artery branches
Additionally, the shape of the pulmonary annulus can also be measured with echocardiography, although this is often technically challenging 4.
CT/MRI
Cross-sectional imaging demonstrates the same radiographic features appreciated on plain film and echocardiography but in greater detail 5,6. In particular, cardiac MRI may be particularly useful for accurate measurements to assess the severity of the valvulopathy and for assessing areas of the heart that are technically challenging to review with echocardiography (e.g. the pulmonary annulus, the right ventricular outflow tract) 5,6.
Treatment and prognosis
The decision to treat pulmonary regurgitation is based on its severity 1. Management involves pharmacotherapy measures (especially diuretics and management of underlying pulmonary arterial hypertension) and consideration of surgery in primary disease 1. Details of this management are beyond the scope of this article.
Complications
See also
- valvular heart disease
- general pulmonary valve pathologies:
- specific pulmonary valve pathologies:
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