Pulmonic Regurgitation

Introduction
Background

The pulmonic valve is normally a thin tricuspid structure that prevents blood from regurgitating into the right ventricle once ejected into the low-pressure pulmonary circulation. Pulmonic regurgitation refers to retrograde flow from the pulmonary artery into the right ventricle during diastole. Physiologic (trace-to-mild) pulmonic regurgitation 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 right ventricular function and eventual clinical manifestations of right-sided volume overload and heart failure. Often, pulmonic regurgitation is not the primary process but a finding secondary to an underlying process such as pulmonary hypertension or dilated cardiomyopathy.

Pathophysiology

Incompetence of the pulmonic valve occurs by 1 of 3 basic pathologic processes: dilatation of the pulmonic valve ring, acquired alteration of pulmonic valve leaflet morphology, or congenital absence or malformation of the valve.
Frequency
United States

Physiologic pulmonic regurgitation is present in nearly all individuals and is a normal echocardiographic finding. Pulmonic regurgitation detected by physical examination is not a normal finding in healthy adults. Congenital pulmonic regurgitation and congenital absence of the pulmonic valve are rare conditions.
International

No difference in international incidence is known.
Mortality/Morbidity

The morbidity and mortality rates associated with pulmonic regurgitation vary considerably, depending on the underlying etiology.
Race

No racial or ethnic predilection exists.
Sex

Differing frequency of pulmonic regurgitation between men and women corresponds to the specific etiology resulting in pulmonic regurgitation.
Age

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 pulmonic regurgitation occur is variable and is primarily related to the underlying process causing the pulmonic regurgitation.
Clinical
History

Pulmonic regurgitation is seldom clinically significant. However, symptoms of right-sided heart failure can occur when the severity and duration of the regurgitation result in right ventricular enlargement and decompensation. Dyspnea on exertion is the most common complaint. Easy fatigability, light-headedness, peripheral edema, chest pain, palpitations, and frank syncope may occur in patients with any cause of right-sided heart failure and do little to elucidate the etiology of the right-sided failure. Patients who experience these symptoms may attribute them to poor physical fitness or anxiety, delaying evaluation until their condition worsens. In more advanced presentations of right-sided heart failure, abdominal distension secondary to ascites, right upper quadrant pain secondary to hepatic distension, and early satiety may occur.

Other symptoms specific to the underlying disease process causing pulmonic regurgitation may occur. Such disease processes include connective-tissue disease, infective endocarditis, carcinoid heart disease, rheumatic heart disease, and primary or secondary pulmonary hypertension. For example, hemoptysis is generally not associated with pulmonic regurgitation per se, but, in severe pulmonary hypertension causing pulmonic regurgitation, it may occur as a result of the associated pulmonary arteriole rupture and hemorrhage and/or parenchymal inflammation.

Physical
Jugular venous pressure (JVP) is usually increased. Often, an increased A wave is present, but this may be less apparent when significant tricuspid regurgitation with a dominant V wave is also present. When right ventricular enlargement is present, a palpable impulse (lift or heave) is usually present at the left lower sternal border. Palpable pulmonary artery pulsation at the left upper sternal border may be present in the setting of significant pulmonary artery dilatation. With significant pulmonary hypertension, pulmonic valve closure can be palpated.
The pulmonic component of the second heart sound (P2) is inaudible in the absence of a pulmonic valve, whether congenital or secondary to surgical resection. In pulmonic regurgitation due to pulmonary hypertension, P2 is accentuated; with increased right ventricular end-diastolic volume, the ejection time is increased, P2 is delayed, and the S2 split is widened.
A low-pressure regurgitant flow across the pulmonic valve, as occurs when the pulmonary arterial pressure is normal, is heard as a brief, decrescendo early diastolic murmur at the upper left sternal border. It is made louder by squatting or inspiration and softer by Valsalva maneuvers or expiration. An S3 or S4 may be noted at the left mid-to-lower sternal border because of the presence of right ventricular hypertrophy or failure and is augmented by inspiration.
The Graham Steell murmur of pulmonary hypertension is a high-pitched, early diastolic decrescendo murmur noted over the left upper-to-left midsternal area and is a result of high-velocity regurgitant flow across an incompetent pulmonic valve. The regurgitant flow murmur may be present during the whole of diastole because there is a pulmonary-to-right ventricular pressure gradient throughout this time period. Typically, the murmur occurs in severe pulmonary hypertension when the pulmonary artery systolic pressure is more than 60 mm Hg. The quality of this high-pitched early decrescendo diastolic murmur is identical to that of aortic insufficiency. However, the peripheral manifestations of aortic insufficiency are absent. The associated findings of tricuspid regurgitation are frequently present, that is, prominent JVP with surging V waves, holosystolic murmur at the lower left sternal border (louder with inspiration), and enlarged, pulsatile liver.
Causes
Significant pulmonic regurgitation occurs variably as a complication of the following:

Primary pulmonary hypertension (~1 instance per 500,000 cases): This diagnosis can be made only after all other causes have been excluded.
Secondary pulmonary hypertension (multiple causes): This is the most common cause of pulmonic regurgitation in adults.
Tetralogy of Fallot: Especially with congenital absence of the pulmonary valve or postoperative following surgical repair of this condition (eg, pulmonary valvotomy).
Infective endocarditis: Rare, but may occur in an intravenous drug user or an individual with an atrial septal defect and a large left-to-right intracardiac shunt.
Rheumatic heart disease: Pulmonary valve affected following mitral, aortic, and tricuspid valve involvement.
Carcinoid heart disease: See Carcinoid Lung Tumors and Carcinoid Tumor, Intestinal.
Medications: Medications that act via serotoninergic pathways (eg, methysergide, pergolide, fenfluramine).
Disorders that dilate the pulmonic valve ring to create valvular incompetence are the most common cause of pulmonic regurgitation.
Primary or secondary pulmonary hypertension
Dilatation of the pulmonary trunk in Marfan syndrome or Takayasu arteritis
Idiopathic
Acquired disorders that alter pulmonic valve morphology
Rheumatic heart disease: In most cases, the other valves (ie, mitral, aortic, tricuspid) are also substantially affected.
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.
Complications related to therapeutic balloon catheter dilatation 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.
Complications of surgical repair of pulmonic stenosis or congenital heart disease, such as tetralogy of Fallot
Syphilis infection
Carcinoid heart disease: The heart is affected in up to 60% of patients in whom carcinoid has metastasized to the liver, most commonly manifesting as valvular disease. In Pellikka and colleagues' 1993 series of 74 patients, the pulmonic valve was involved in 88%. Of those, 49% exhibited significant pulmonic stenosis, and 81% had significant pulmonic regurgitation.1
Congenital disorders that produce an incompetent pulmonic valve
Complete absence of the pulmonic valve
Valvular abnormalities such as fenestrations or redundant leaflets

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