Surgery for Heart Disease in Pregnancy

Dateline: 08/23/98

Pregnancy is one of the physiological conditions that places a considerable burden on the heart, forcing it to work harder for a significantly long period - nine months. While a normal heart is quite capable of taking this extra workload right in its stride, a diseased one may not be able to cope. Different kinds of heart disease may cause different problems during pregnancy. In this series of articles I plan to discuss this topic in depth.

What are the indications for heart surgery ?

Heart surgery is necessary when

• medical treatment fails to control heart failure
• symptoms are intolerable to the patient despite medical therapy

Closed Mitral Valvuloplasty (CMV)

While open heart surgery is not undertaken lightly during pregnancy because of the risks to the fetus, closed mitral valvuloplasty (CMV) for mitral stenosis can be done relatively safely. CMV is advised in

• severe congestion of the lungs (with blood), unresponsive to drugs quickly
• any episode of pulmonary edema before pregnancy (because there is a high chance of a recurrent attack during this pregnancy)
• profuse hemoptysis (coughing out blood)

While the second trimester of pregnancy is usually preferred for any heart operation, CMV can be safely performed at any stage of pregnancy if needed.

In recent times, the introduction of the balloon valvotomy procedure to widen the mitral valve has made non-surgical treatment available for mitral valve stenosis. The disadvantages in pregnancy are

1. radiation exposure
2. need to assume the supine position for a long period, which can decrease blood pressure in pregnant women

Aortic valvotomy is sometimes done for critical aortic valve stenosis during pregnancy. Almost always, this is a temporary measure to tide over the pregnancy, after which most patients will require an aortic valve replacement operation.

Open Heart Surgery during pregnancy

The decision to perform open heart surgery in a pregnant woman is a difficult one. The risks to the fetus are considerable, and only in serious heart disease that would be harmful to the mother if left untreated can such a major procedure be justified. Such conditions would include life threatening pulmonary edema which cannot be managed medically. Open heart surgery is rarely indicated for congenital heart disease in pregnancy.

Maternal outcome after open heart surgery has been reasonably good in several series. The reason for this is probably the inadequate blood flow to the placenta during the period of heart lung bypass as a result of the lower blood pressure and non-pulsatile nature of blood flow. All these cases however were reported to have had surgery during the first trimester (first 12 weeks) of pregnancy.

In the next article, we will discuss aspects of ante-natal care of heart disease patients during the pregnancy.