Pulmonic sricture

Description, Causes and Risk Factors:

Pulmonic stricture is narrowing of the pulmonary artery, a large artery that sends oxygen-poor blood into the lungs to be enriched with oxygen. The narrowing may occur in the main pulmonary artery and/or in the left or right pulmonary artery branches. This narrowing makes it difficult for blood to reach the lungs to pick up oxygen. Without enough oxygen, the heart and body cannot function as they should. In an effort to overcome the narrowing, the pressure in the right ventricle (the chamber that pumps blood into the pulmonary arteries) rises to levels that can be damaging to the heart muscle.

Causes and Risk Factors:

Tetralogy of Fallot - a four-pronged defect consisting of:

• A ventricular septal defect.

• A narrowing at or just beneath the pulmonary valve.

• A right ventricle that is more muscular than normal.

• An aorta that lies directly over the ventricular septal defect.

• Pulmonary atresia - absence of a pulmonary valve, preventing blood from flowing from the right ventricle into the pulmonary artery and onward to the lungs.

• Truncus arteriosus - the formation of only one combined artery instead of the normal two outlets from the heart, the aorta and pulmonary artery.

• Pulmonary valve stenosis - problems with the pulmonary valve (for example, development of less than three leaflets, leaflets that may be partially fused together, thick leaflets that do not open all the way) that make it more difficult for the valve leaflets to open and permit blood to flow from the right ventricle to the lungs.

• Patent ductus arteriosus - an open passageway between the pulmonary artery and the aorta. Normally, this passageway closes on its own within a few hours of birth, but when it does not, surgery or an outpatient catheter-based procedure is needed to close the opening

The exact prevalence is unknown.

Symptoms:

Dyspnea on exertion.

• Exercise intolerance.

• Exercise-dependent fatigue.

• Palpitations.

• Presyncope and syncope.

• Angina pectoris.

Signs:

Systolic ejection click.

• Widely split second heart sound.

• Harsh spindle-shaped ejection murmur.

• Left parasternal thrill.

• Right ventricular impulse.

• Distended neck veins.

• Cyanosis, clubbing of the fingers.

Diagnosis:

Diagnosis may include:

EKG/ECG: ECG/EKG shows signs of atrial dilatation and right ventricular hypertrophy (RVH).

• Chest radiograph: The chest film shows signs of right atrial and right ventricular enlargement and prominent pulmonary arteries. There is no evidence of increased lung perfusion, and decreased perfusion of the peripheral lung vessels is occasionally noted. Doppler echocardiography can measure the pressure gradient across the pulmonary valve. In case of severe pulmonic stenosis the pressure gradient exceeds 80 mmHg.

• Pulmonary angiography - a dye-enhanced x-ray of the pulmonary arteries and veins of the heart.

• Perfusion scan - a test in which the patient is injected with a small amount of a radioactive material. A special machine shows how well blood is flowing through each of the two lungs.

Treatment:

Treatment for pulmonary stricture will vary depending on the severity of the condition and age of the patient. At present most cases of pulmonary stricture are treated by percutaneous valvuloplasty. Disruption of the valve shortenthe length of the right ventricular outflow tract in adults. This leads to an increase in infundibular muscular stenosis, often necessitating a limited course of therapy with beta blockers.

Balloon dilation and stent placement: In an effort to improve on the results of balloon dilation, a search for a more effective treatment was begun and led to the development of the stainless steel balloon-expandable stent. Stent placement is accomplished by positioning the stent across the narrowed segment of the artery. The stent is mounted on a balloon angioplasty catheter and covered with a sheath as it is moved into position. The sheath then is withdrawn off the stent-balloon angioplasty assembly and the balloon is inflated to its recommended pressure, expanding the stent and anchoring it in place.

The Cutting Balloon Technique™: This procedure is similar to standard balloon dilation but the balloon has been specially designed with small blades running up and down its length. When the balloon is inflated, the blades are activated and they cut through the narrowed area, making the vessel easier to dilate and resulting in a larger opening. Cutting balloons are available in different sizes.

Complications such as fluid collection around the heart or lungs occur after the surgery, but these are rarely serious.

NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.

DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.