Pathology of pulmonic valve stenosis and pure regurgitation

Abstract

Summary:Little morphologic information is available on o p eratively excised pulmonic valves. The causes of pulmonic stenofi\ are limited to a few conditions: (1) rhewnatic and (2) nonrheiiinulic (congenital, carcinoid, infective endocarditis). Congenital causes of pulmonic stenosis constitute well over 95% of the\e conditions. Congenital types of pulmonic stenosis include acommissural dome-shaped, dysplastic, and bicuspid. Rare acquired causes of pulmonic stenosis include carcinoid, rheumatic, and infective endocarditis. Of the acquired causes of pulmonic stenosis, carcinoid is the most common condition. In contrast. causes of pure pulmonic regurgitation are multiple. Two mqjor categories of pure pulmonic regurgitation include ( 1 ) conditions associated with anatomically a b n o m l valve cusps (congenital, rheumatic, carcinoid, trauma, and infective endocarditis) and (2) conditions associated with anatomically nonnal cusps (elevated pulmonary artery systolic pressures, idiopathic dilated pulmonary trunk, and Marfan's syndrome).

Causes and hemodynamic findings in chronic severe pulmonary regurgitation

“…The most common cause of severe PR is as a sequelae of treatment of a congenital disorder involving the pulmonic valve and/or RV outflow tract, most frequently Tetralogy of Fallot or pulmonic stenosis . Many tetralogy patients have small pulmonary arteries and right ventricular outflow tracts and one surgical approach to treating RV outflow tract narrowing is dissection of the pulmonary annulus and enlargement with a transannular patch.…”

“…Subsequently, this approach has been essentially replaced with balloon valvuloplasty. Both approaches can lead to PR over time due to dilation of the annulus and/or damage to the pulmonic valve leaflets . One review found that 57% of children who underwent percutaneous balloon valvuloplasty developed moderate to severe PR .…”

“…Severe PR in the absence of prior treatment of RV outflow obstruction or pulmonic stenosis is a rare occurrence . Causes of PR can be classified into two groups based on whether the pulmonic valve is anatomically normal or abnormal.…”

“…This can be congenital or acquired and has been seen with both primary and secondary pulmonary hypertension. Other causes include Marfan's syndrome, idiopathic pulmonary artery dilation, and connective tissue disorders . Congenital disorders with anatomically abnormal pulmonic valves resulting in severe PR include absent valves, absent leaflets, bicuspid valve, malformed tricuspid valve, and quadricuspid valve .…”

“…Infective endocarditis is the most common cause of acquired PR and can cause either tissue perforation or fibrosis of the leaflets leading to poor coaptation . Pulmonic valvular endocarditis is a rare phenomenon occurring in 1.5–2% of admissions for endocarditis and only 38 cases have been reported in 40 years in structurally normal valves .…”