Practice Essentials
Pulmonary or pulmonic regurgitation (PR) is defined as an abnormal reversal of blood flow from the pulmonary artery into the right ventricle. Most often, PR is not the primary process but a finding secondary to an underlying process, such as pulmonary hypertension or dilated cardiomyopathy.
Signs and symptoms
Patients with PR are typically asymptomatic prior to the onset of right ventricular (RV) dysfunction. Symptoms consist of exertional dyspnea and fatigue. With the progression of RV dysfunction, the onset of atrial and ventricular arrhythmias, palpitations, and syncope may occur.
The murmur is in early diastole and it may increase in intensity with inspiration. With more signicant PR, an ejection murmur in systole may be heard and a third heart sound may be present.
Significant PR can be associated with the following symptoms:
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Distended neck veins
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Palpable pulmonary artery pulsation
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Pedal edema
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Hepatosplenomegaly
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Ascites
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Syncope
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Lightheadedness
Diagnosis
Echocardiography generally confirms the diagnosis of PR, which also provides an evaluation of the mechanism, cause, and severity of the valve disease. In addition, echocardiography provides information about the hemodynamic effects and the assessment of associated disorders, such as pulmonary artery hypertension. PR severity is determined by jet width, density, and deceleration rate. Patients with moderate or greater PR should also undergo evaluation with cardiovascular magnetic resonance imaging (CMRI) to provide a quantitative assessment of PR and of RV size and function.
Imaging studies
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Radiography
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Echocardiography
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Computed tomography scanning
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CMRI
Management
PR is seldom severe enough to warrant special treatment. It is recommended to treat the underlying etiologies that cause severe PR. When right-sided heart failure due to PR cannot be ameliorated by medical therapy, surgical reconstruction or replacement of the pulmonic valve is an appropriate option.
The following are indications for surgical pulmonic valve replacement:
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Severe, symptomatic PR
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Asympatomatic severe PR with severe RV dilatation and/or dysfunction, or symptomatic atrial and/or ventricular arrythmias; dysfunction on CMRI with a RV end-diastolic volume above 150 mL/m 2, an end-systolic volume over 80 mL/m 2, and an ejection fraction below 47%
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Severe PR and progressive tricuspid valve regurgitation
Background
The pulmonic valve is normally a thin tricuspid structure that prevents blood from regurgitating into the right ventricle (RV) once it is ejected into the low-pressure pulmonary circulation. Pulmonary or pulmonic regurgitation (PR) refers to retrograde flow from the pulmonary artery into the RV during diastole. Physiologic (trace to mild) PR is present in nearly all individuals, particularly in those with advanced age. However, pathologic conditions that produce excessive and clinically significant regurgitation can result in impairment of RV function and eventual clinical manifestations of right-sided volume overload and heart failure. Most often, PR is not the primary process but a finding secondary to an underlying process such as pulmonary hypertension or dilated cardiomyopathy.
Pathophysiology
Pulmonary or pulmonic regurgitation (PR) or incompetence of the pulmonic valve occurs by one of three basic pathologic processes: dilatation of the pulmonic valve ring, acquired alteration of the pulmonic valve leaflet morphology, or congenital absence or malformation of the valve. PR leads to right ventricular (RV) volume overload, which will subsequently lead to RV enlargement and RV dysfunction. In time, PR will lead to tricuspid regurgitation.
Etiology
Significant pulmonary or pulmonic regurgitation (PR) occurs variably as a complication of various conditions.
The most common causes for a leaky pulmonary valve is pulmonary hypertension or a congenital heart defect (most commonly tetralogy of Fallot).
Less common causes of PR include the following:
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Carcinoid syndrome
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Complications following surgical repair of tetralogy of Fallot
Primary and pulmonary hypertension
Primary pulmonary hypertension occurs in approximately 1 per 500,000 cases. This diagnosis can be made only after all other causes have been excluded. Primary causes include iatrogenic, infective endocarditis, systemic (carcinoid disease), immune-mediated (rheumatic heart disease), and congenital heart disease. [1, 2]
Secondary pulmonary hypertension (multiple causes) is the most common cause of pulmonic regurgitation in adults. Secondary or functional PR occurs in patients with nromal pulmonic valve who have severe pulmonary arterial hypertension and/or pulmonary artery dilatation. [3]
Tetralogy of Fallot
Tetralogy of Fallot, especially with congenital absence of the pulmonary valve, or postoperative following surgical repair of this condition (eg, pulmonary valvotomy), commonly cause significant PR. [4]
Infective endocarditis
In rare cases, infective endocarditis results in significant PR. It may occur in an intravenous/injection drug user or in an individual with an atrial septal defect and a large left-to-right intracardiac shunt.
Rheumatic and carcinoid heart diseases
In rheumatic heart disease leading to significant PR, the pulmonary valve is affected following mitral, aortic, and tricuspid valve involvement.
For more information on carcinoid heart disease, see Carcinoid Lung Tumors and Intestinal Carcinoid Tumor.
Medications
Medications that act via serotoninergic pathways may result in significant PR (eg, methysergide, pergolide, fenfluramine).
Disorders that dilate the pulmonic valve ring to create valvular incompetence
Disorders that dilate the pulmonic valve ring to create valvular incompetence are the most common cause of PR and include primary or secondary pulmonary hypertension, dilatation of the pulmonary trunk in Marfan syndrome or Takayasu arteritis, and idiopathic causes.
Acquired disorders that alter pulmonic valve morphology
Acquired conditions that alter pulmonic valve morphology include the following:
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Rheumatic heart disease: In most cases, the other valves (ie, mitral, aortic, tricuspid) are also substantially affected.
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Trauma from a Swan-Ganz catheter: This cause is unusual, but it can result if the catheter tip is withdrawn across the pulmonic valve with the balloon inflated.
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Complications related to therapeutic balloon catheter dilation of a stenotic pulmonic valve (eg, pulmonary balloon valvuloplasty): Such complications are not uncommon; however, in most cases, the degree of regurgitation is clinically insignificant, rendering pulmonic valve balloon catheter dilation a safe and effective treatment for moderate to severe pulmonic stenosis in adult and pediatric patients.
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Syphilis infection
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Carcinoid heart disease: The heart is affected in up to 60% of patients in whom carcinoid heart disease has metastasized to the liver, most commonly manifesting as valvular disease. In a series of 74 patients, the pulmonic valve was involved in 88%. [8] Of those affected, 49% exhibited significant pulmonic stenosis, and 81% had significant PR.
Congenital disorders that produce an incompetent pulmonic valve
These include complete absence of the pulmonic valve and valvular abnormalities (eg, fenestrations or redundant leaflets).
Epidemiology
United States
Physiologic pulmonary or pulmonic regurgitation (PR) is present in nearly all individuals and is a normal echocardiographic finding. PR detected by physical examination is not a normal finding in healthy adults. Congenital PR and congenital absence of the pulmonic valve are rare conditions.
International
No difference in international incidence is known.
Race-, sex-, and age-related demographics
No racial or ethnic predilection exists.
The differing frequency of PR between men and women corresponds to the specific etiology resulting in this condition.
Except for congenital absence of the pulmonic valve, which is more likely to cause right-sided ventricular decompensation early in life, the age at which clinical symptoms of PR occur is variable and is primarily related to the underlying process causing the PR. Patients are usually in their third or fourth decade of life at presentation, typically with severe PR that is manifested by surgical repair.
Prognosis
The prognosis for patients with severe pulmonary or pulmonic regurgitation (PR) depends on the presence or absence of right ventricular (RV) dysfunction, pulmonary artery dilatation, and symptoms.
Most patients with with PR following repair of tetralogy of Fallot carry an excellent prognosis. However there is a late mortality that is related to RV dysfunction. [4, 9] Residual PR is an important determinant of outcome, as it may contribute to RV hypertrophy and dysfunction, a propensity for arrhythmias, and an increased risk for sudden cardiac death. [10, 11]
In general, survival is not significantly affected by mild to moderate PR. If the PR is severe, the RV is initially able to compensate for the volume overload state, and the state may remain well compensated for years. However, persistently elevated RV volumes may eventually cause RV dilatation and, finally, failure.
As previously stated, the various disorders causing pulmonary hypertension are the most common causes of clinically significant PR. The principal prognostic indicators of mortality in PR associated with pulmonary hypertension are (1) the severity and duration of the pulmonary hypertension at the time of diagnosis and (2) the RV response to the state of volume overload.
In all etiologies of pulmonary hypertension, early diagnosis that allows for intervention to slow or reverse the cause of pulmonary hypertension is essential, although, in many cases, diagnosis is difficult and requires a high degree of clinical suspicion.
In primary pulmonary hypertension, the pathologic process is often insidious, and symptoms manifest at an advanced disease state, resulting in an average survival period of 2.5 years from the time of diagnosis.
In congenital regurgitation of the pulmonic valve, the prognosis depends upon the initial severity, progression of the regurgitation, and the ability of the RV to adapt to volume overload. Usually, the degree of regurgitation in this condition is no more than moderate, so no clinical sequelae occur. Congenital absence of the pulmonic valve, a much rarer condition, confers an increased risk of morbidity and mortality because of more severe regurgitation, and it usually warrants pulmonic valve replacement for improved prognosis.
Morbidity, mortality, and complications
As noted, the morbidity and mortality rates associated with pulmonic regurgitation vary considerably, depending on the underlying etiology.
Severe pulmonary valve regurgitation may result in RV enlargement, systolic dysfunction, and death. [4, 12, 13] Complications of severe PR may lead to right-sided heart failure (itself a complication of RV volume overload), thromboembolic events, hepatic congestion, systolic dysfunction, arrhythmias, and death.
Other complications are related to the underlying disease processes resulting in PR.
After a pulmonic valve replacement, infective endocarditis and structural valve failure are signifcant long-term complications. [14]
Patient Education
Carefully explain to patients that pulmonary or pulmonic regurgitation (PR) is in essence a leaky pulmonary valve. The pulmonary valve helps control the flow of blood passing from the heart to the lungs. Thus, a leaky pulmonary valve permits blood to flow back into the heart chamber before it returns to the lungs and becomes oxygenated.
If symptoms occur, patients should be reviewed by their physicians. Although there is little available on the risk of endocarditis following pulmonary valve surgery, the current recommendation is to provide antibiotic prophylaxis before dental or urologic procedures.
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Continuous-wave signal of transpulmonary flow in severe pulmonary regurgitation. Courtesy of Wikimedia Commons [AMC Echolab, AMC, The Netherlands].
