Etiology

Pulmonary regurgitation may be congenital or acquired. In the acquired form it may result from any left-sided cardiac condition, such as mitral stenosis, or severe pulmonary disease and pulmonary hypertension. Other known causes are dilation of the pulmonary annulus secondary to pulmonary hypertension or post balloon valvuloplasty for pulmonary valve stenosis. Endocarditis may destroy the integrity of the pulmonary valve leaflets, resulting in pulmonary regurgitation.[1][3]​ Other conditions that may result in abnormal pulmonary valve leaflets are congenital anomalies, rheumatic heart disease, carcinoid heart disease, syphilis, and trauma (e.g., from a Swan-Ganz catheter).[4] Connective tissue disease, such as Marfan syndrome, may also be an associated cause.[4] Very rarely, it may be caused by primary or metastatic malignancies that involve the main pulmonary artery.

In addition, the acquired form commonly results decades after surgical repair of tetralogy of Fallot, pulmonary stenosis, or atresia. It has also been associated with the Ross procedure (pulmonary autograft used for aortic valve replacement).[5]

Pathophysiology

Severe isolated pulmonary valve regurgitation is rare. However, when present, it results in volume overload and dilation of the right ventricle with compensatory right ventricular (RV) hypertrophy. Eventually, this results in equalization of the pulmonary artery pressure and the RV pressure in diastole. Furthermore, with severe progression and RV failure, right-sided stroke volume decreases, leading to peripheral edema, dyspnea, and easy fatigability.

Pulmonary regurgitation associated with pulmonary hypertension is usually nonsignificant and has few to no hemodynamic consequences. It is the pulmonary hypertension that results in RV failure and dilation and low right-sided cardiac output.

The regurgitant pulmonary volume depends on several factors:[3]

  • Diastolic filling period

  • The regurgitant orifice dimension

  • Pressure gradient across pulmonary valve

  • Pulmonary artery distensibility

  • RV compliance and function.

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