Right ventricular outflow tract obstruction overview

WikiDoc Microchapters for Right ventricular outflow tract obstruction
Right ventricular outflow tract obstruction Home
Overview
Anatomy of Pulmonary valve
Classification
Pulmonary valve stenosis Pulmonary subvalvular stenosis Pulmonary supravalvular stenosis Pulmonary valve atresia
Diagnosis
Differential diagnosis Symptoms Physical examination Electrocardiogram Chest x ray Echocardiography Cardiac catheterization Pulmonary angiography
Management

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Associate Editors-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Keri Shafer, M.D. [3]

Overview

Right ventricular outflow tract (RVOT) and/or pulmonary artery obstruction are present in some form in 25 % of all congenital heart defects. The right ventricular outflow tract obstruction includes stenosis or narrowing of the pulmonary valve, the tissue above the valve (supravalvar obstruction) and below it(subvalvar obstruction). Congenital subvalvar and supravalvar right ventricular outflow tract stenosis usually occurs with other congenital heart defects such as Ventricular Septal Defect (VSD) or Tetralogy of Fallot. The timing and type of surgery will vary from patient to patient depending upon the severity of the obstruction and the associated congenital defect.

If right ventricular outflow tract obstruction is present and the ventricular septum is intact, usually the right ventricle will adapt better given that no right to left shunting is present. This absence of shunting may result in sufficient pulmonary blood flow to allow the patient to remain asymptomatic longer.

Pulmonary stenosis is one of the most common RVOT obstructions. The oxygen-depleted blood is coming from the body to the heart through the superior and inferior vena cava, arriving into the right atrium, right ventricle, passing through the RVOT and pulmonary valve to the pulmonary artery and lungs to pick up oxygen. Normally the pulmonary valve has three leaflets. These leaflets can be malformed due to congenital defects, producing pulmonary valve narrowing (stenotic) or leaky (insufficient). If the pulmonary valve is tight (stenosis), the right side of the heart needs to work harder to push blood through the valve to the lungs. The stenosis, insufficiency or both can be mild to severe. Therefore the symptoms will depend upon the grades of pulmonary stenosis.

Usually therapy is directed to increase pulmonary blood flow and decompressing the right ventricle (RV) and it will depend on the severity and location of the defect. According to the anatomic features of the pulmonary valve stenosis, the physician may use balloon dilatation (a minimally invasive transvenous procedure) to dilate the obstruction during cardiac catheterization, but if the pulmonary artery is the structure involved, stenting (insertion of a small tube) within the narrowed region can be done following balloon angioplasty. Standard treatment of right ventricular outflow tract or pulmonary artery obstruction involves open chest surgery.