"Questions and Answers with Thomas Di Sessa, M.D."
- Written by:
- Thomas Di Sessa, M.D.
- Chief, Division of Pediatric Cardiology
- University of Tennessee, Memphis
Edited by: Mona Barmash
Posted: April 17, 1998
Pregnancy in women with repaired or palliated congenital heart disease
- Q. What research has been, is being done on pregnancy in adults with congenital heart disease?
- A. A seminar was given during the recent American Heart Association 70th Scientific Session. The title of the seminar was "Managing Heart Disease in Pregnancy ". The seminar moderator was Joseph K. Perloff, M.D., Professor of Medicine at the University of California, Los Angeles. Although Dr.Perloff is not doing active research in the area, he is one of the world's authorities on pregnancy in heart disease.
- Research on the following topics were presented:
- Cardiovascular physiology of pregnancy - Roberto M. Lang, M.D. (Chicago, IL)
Heart Disease that occurs during pregnancy - Marla A. Mendelson, M.D. (Chicago, IL)
Pregnancy and artificial heart valves - Dr. Shahbdudin H. Rahimtoola ( USC- Los Angeles)
Congenital Heart Disease and pregnancy - Carole A. Warnes, M.D. (Mayo Clinic)
- Q. Are there publications about other forms of congenital heart disease besides the Fontan in terms of pregnancy?
- A. Yes, there are other publications. The best reference from a medical standpoint is a textbook entitled "Congenital Heart Disease in Adults" by Joseph Perloff, M.D. and John Childs, M.D., published by W. B. Saunders Company. Chapter 9 is entitled: Pregnancy and Congenital Heart Disease: The Mother and the Fetus.
- Q. How many women do you see per year who are considering getting pregnant? What happens with most of them?
- A. I see approximately 2-3 women per year with either repaired or unrepaired congenital heart disease who are considering becoming pregnant. The outcome of pregnancy in these women depends upon the type of congenital heart disease. In my experience, I have had one maternal death and 2 fetal deaths. Most have done well.
- Q. What types of congenital heart disease are more likely to experience complications during pregnancy?
- A. The answer to this question is rather broad. I will try to summarize it briefly. Certainly women with severe, unrepaired forms of congenital heart disease are at high risk during pregnancy. Patients that are palliated (not completely repaired with separation of the circulations) are at high risk. The woman who has had a Fontan operation may to be at some risk. The cyanotic woman and the woman with pulmonary hypertension are at exceptional risk for a complication during pregnancy.
- If one examines mortality in women during pregnancy and uses the New York Heart Association functional classification for severity of heart disease, mortality is highest in women who are class III and IV; their mortality is about 6.8%. Another major risk factor for the woman who decides to become pregnant is the presence of congestive heart failure with lung fluid (pulmonary edema). Other major risk factors include severe obstruction to blood flow from the left ventricle, which has a 17% mortality, and Marfan Syndrome with a large aorta.
- Q. Are there some doctors or hospitals that specialize in women with congenital heart disease who have become pregnant?
- A. Most women with congenital heart disease who have become pregnant are cared for in high risk obstetrical settings, by physicians who are expert in this area.
- Q. Have any of your adult patients suffered from severe complications due to pregnancy, for example strokes?
- A. Yes, we have had 1 death from a stroke in a woman who did not seek obstetrical care during the pregnancy. Another woman had severe bleeding post-birth.
- Q. I have read that Fontans are having good luck with pregnancy. From what you said, that does not seem to be true. What is the advice given to Fontan patients about pregnancy?
- A. The most recent literature concerning women who have had the Fontan operation and who have become pregnant was published by Mary Canobbio, M.N., R.N. and Douglas Mair, M.D. et.al. in The Journal of the American College of Cardiology. They studied 33 pregnancies in 21 female patients who have had the Fontan operation. There were 15 live births in these 33 pregnancies. In addition, there were 13 spontaneous abortions (miscarriages) and 5 elective terminations. Problems reported prior to pregnancy included atrial flutter (an abnormally fast heart rate) in 1 patient and cardiac dysfunction in another, aortic valve regurgitation (leak) and atrioventricular (inlet) valve regurgitation (leak) in another. One patient developed supraventricular tachycardia (abnormally fast heart rate) during pregnancy. There were no maternal cardiac complications reported during labor, delivery, or immediately post-delivery. Thus, it appears from these data that the woman who has had a Fontan operation fares well during pregnancy. However, the high incidence of spontaneous abortion may indicate that the fetus does not do well during the Fontan pregnancy.
- As to the advisability of pregnancy after the Fontan operation, the woman needs to be aware of the following and discuss the subject with her obstetrician, if necessary:
- The pregnant woman increases blood volume and cardiac output by 50% during pregnancy. In addition, patients who have had the Fontan operation have a limited cardiac output (cardiac output is the volume of blood that the heart distributes to the body in a minute). Normal cardiac output is approximately 3-4 liters per minute per meter squared of body surface area. Patients with the Fontan operation have a cardiac output of 2-3 liters, or less. In addition, their cardiac reserve, or the amount of blood that the heart can pump per minute with exercise, is somewhat limited. Thus, some of these women may not have the cardiac reserve to support pregnancy. The inability to increase cardiac output appropriately may be the reason for the high frequency of spontaneous abortion or miscarriage. The fetus may not be getting enough blood supply.
- Furthermore, I believe it is well known that patients who have had the Fontan operation have problems with fluid after the operation. Many patients have to take diuretics long-term after the operation. Thus, it seems reasonable to assume that increasing blood volume by a significant amount would create problems with the Fontan circulation. Canobbio's study evaluated only 33 pregnancies in 21 women and only 15 went to term. This is a rather small sample to make broad statements from. Although these data are promising, the ultimate answer remains to come forward.
- Q. How common is it to overlook an atrial septal defect and other defects with multiple echo examinations?
- A. It can be quite common in the adult patient. The size of the adult patient sometimes prohibits transmission of the ultrasound waves to the heart. Images are often not very clear. It is becoming apparent that the best method for imaging the adult with congenital heart disease may be with the use of transesophageal echocardiography. In other words, an echo transducer that has been reduced in size to fit into the esophagus is passed into the mouth and into the esophagus behind the heart. The esophagus in essence touches the back of the heart so the close proximity of the heart to the transducer provides excellent imaging.
- Q. How about in infants and children? Is this something that can be difficult to image on echo?
- A. In infants and children, the reliability of echocardiography depends upon the experience of the doctor reading the ultrasound images and upon the experience of the technician obtaining the images. If the images are not acquired well, the physician reading the images, no matter how expert, can overlook problems. In addition, the images may be obtained in an excellent manner but the physician may not have the expertise to read the images. In general, atrial septal defect and other common abnormalities in children are seldom missed by pediatric echocardiographers.
- Q. What are the major long-term differences in the extra-cardiac Fontan and the regular Fontan that goes through the atrium?
- A. The extra-cardiac Fontan uses a tube made of Gortex that connects the inferior vena cava to the pulmonary artery along the outside of the right atrium. (See Figure.) This operation has only been used for the past 3-4 years. Thus, it becomes some what problematic to discuss long term differences. It has the oretical advantages over the Fontan that goes through the atrium. (See Figure.) These advantages include: (1) better flow characteristics and, (2) a reduction in the frequency of heart rate changes (arrhythmias) that occur after the Fontan operation. The Gortex tube may have the disadvantage of in-growth of tissue into the conduit. Tissue that does grow into the conduit (tube) can make the size of the conduit smaller and ultimately create obstruction. We know from the use of Dacron conduits within the heart that this does happen. It also happens with Gortex shunts (connections between the aorta and pulmonary artery). Thus, long term outcome is pretty much unknown.
- Surgeons have entertained the notion of using human homograft conduits instead of Gortex conduits. These human conduits tend to undergo a rejection process and can shrink and calcify. If there is enough shrinkage of the human conduit, obstruction can also occur. I must stress , however, that to date nearly all surgeons are using Gortex for the extra-cardiac Fontan. In addition, I must stress that long term outcome is still unknown.
- Q. Do you watch this with echo?
- A. Yes, this can be evaluated with echo. In particular the Doppler component of the echo will be able to detect flow disturbances within the conduit.
- Q. Pleural effusions have kept most Fontan kids in the hospital. Why does this occur after the Fontan operation?
- A. It is an adaptive response to the increased right atrial pressures after the Fontan. In addition, there are certain hormonal problems that occur after the Fontan operation. I will discuss first the pressure issue. Normal right atrial pressures are approximately 3-4 mmHg on an average. Immediately after the Fontan operation, right atrial pressures can be in excess of 20 mmHg. Leakage of fluid into a body cavity occurs when the pressure within a vessel exceeds the pressure that keeps fluid in the vessel. Pressure that keeps fluid in the vessel is created by the protein and blood products in the circulation. The critical pressures that allow for seepage of fluid into the body cavity occur above 18 mmHg. The Fontan who has compensated well has a pressure in the right atrium of approximately 10-15 mmHg. Thus, if pressure in the right atrium is excessive, fluid will leak into the pleural space.
- Pressure is not the only problem that is happening. There is also a problem when the kidney retains salt and fluid. This occurs as a response to circulating hormonal changes.
- The length of time that it takes for the circulation to adjust to the fluid retention and pressures in the right atrium is quite variable. It can be anywhere from days to weeks to months.
- Many surgeons have employed the use of a fenestration (a hole between the right atrium and left atrium after the Fontan) to reduce the pressures in the right atrium and reduce the risk of fluid accumulations. This is called a fenestrated Fontan operation. The fenestration can be adjustable and the fenestration (hole) can gradually be closed non-surgically, usually during a heart catheterization procedure.
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- This article was reviewed prior to publication by:
- Richard Donner, M.D.
- Chief, Pediatric Cardiology,
- Temple University School of Medicine
- Co-Chief, Pediatric Cardiology,
- St. Christopher's Hospital for Children
- Philadelphia, PA
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