What is constrictive pericarditis?

What is constrictive pericarditis?

Constrictive pericarditis is thickening and scarring of the outer covering of the heart over a long period. The outer covering of the heart is called pericardium. The thickened pericardium acts as a restraint to proper filling of the heart when it relaxes after a contraction. When the filling of the heart is impaired too much, the back pressure is transmitted into the great veins which bring blood to the heart.

The superior vena cava from the upper part of the body is enlarged and along with it, the veins in the neck become distended. Veins are the blood vessels returning oxygen poor blood to the heart for pumping to the lungs for oxygen enrichment. The inferior vena cava which brings blood from the lower part of the body is also distended and at high pressure. This produces enlargement of the liver, collection of fluid within the tummy and the under the skin of the legs. In severe cases the person has breathlessness.

Tuberculosis is an important cause of constrictive pericarditis in regions where it is prevalent. Other bacterial infections of the pericardium can also lead to constrictive pericarditis later. Injury to the pericardium during a heart operation is also a rare cause of constrictive pericarditis. Radiation given for cancer of the adjacent organs like breast and lungs can also affect the pericardium as a collateral damage. Rarely this can lead to constrictive pericarditis in the long run. Sometimes the cause of constrictive pericarditis may not be evident by the time the disease manifests after a long time.

The disease is slowly progressive and hence the diagnosis is often delayed. Because of fluid collection in the tummy and liver enlargement, it may be mistaken for liver disease initially. But distension of the neck veins differentiates it from liver disease without heart failure. In advanced long standing cases, there is deposition of calcium within the thickened pericardium, which can be seen even on routine chest X-ray. In earlier cases, calcium will be visible on image intensifier fluoroscopy, a more advanced type of X-ray imaging. Excess calcium deposits and increase in thickness of the pericardium can be seen well on computed tomography (CT scan).

Echocardiography or ultrasound imaging of the heart is also useful in diagnosis of constrictive pericarditis. It will show the increased thickness of pericardium as well as enlargement of the superior and inferior vena cava. There are also important patterns on a special mode of echocardiography known as Doppler echocardiography which measures the blood flow velocity in different parts of the heart. CT scan is superior to echocardiography in measuring the calcium deposits and thickness of pericardium.

Another important test which may be done in suspected constrictive pericarditis is cardiac catheterization. In cardiac catheterization, small tubes known as catheters are introduced through the blood vessels of the groin into the heart, guided by X-ray imaging. The procedure is done in a special procedure room known as cardiac catheterization laboratory (cathlab). Measurements of pressure tracing from the various chambers of the heart is useful in the diagnosis of constrictive pericarditis. In older persons, visualization of blood vessels of the heart after injecting radiocontrast medications by a test known as coronary angiography may also be done.

Once the diagnosis is confirmed, treatment is usually removal of the thickened pericardium by a surgery called pericardiectomy. For better results, pericardiectomy has to be done early in the course of the disease. If it is done after a long time, the thickened pericardium is quite adherent to the heart and may be difficult to remove. Injury to the heart muscle and the blood vessels of the heart may occur while removing grossly thickened pericardium with a lot of calcium deposits.