Fetal Heart Surgery - Survival

Dateline: 03/15/98

With the explosion of technology in cardiac surgery, it is difficult to point to one development and say "This is it, THIS is the most innovative advance in recent times". Over the past month, we have discussed the concept of minimally invasive heart surgery, and the use of this novel technique in treating coronary artery disease , heart valve disease and birth defects of the heart. For more information on minimally invasive surgery, visit the MICAS website. However, the concept of treating diseases of the heart even when the "child" is in the womb - fetal intervention - is perhaps the nearest to "IT".

Fetal Heart Surgery is an idea which has totally captured my imagination. It has strong detractors as well. So I thought of starting a forum to discuss this contentious issue. Many, many issues are involved. I will discuss some of them here. It would be nice if you could suggest others as well. You can post your comments on the Bulletin Board.

This week, the issue is ....

SURVIVAL AFTER FETAL SURGERY ?

The yardstick by which we measure the success of a surgical procedure is SURVIVAL.

• How many patients live through the operation with relief of their problems ?

• How long do they live ?

• And how well are they ?

In fetal surgery, a peculiar situation exists. Each intervention would have TWO survivals. The first survival would be after the fetal operation is performed, and the fetus replaced within the protective womb. Heart action would have to recover enough to sustain life through the rest of the gestational period.

The second survival would be the REAL one, when the fetus reaches viability and is delivered at or near term. At this time, in every sense - legal, medical and ethical - the child could be called a "survivor" .

Its "early days" yet, and we have absolutely no evidence to say what kind of survival can be expected after fetal surgical interventions. This is why, atleast to begin with, fetal surgery can only be recommended for those extremely sick fetuses, with complex malformations which anyway have a high attrition rate when untreated.

Most investigators in the field firmly believe that the concept of in-utero correction has the potential to salvage a significant proportion of fetuses which would otherwise NOT make it through pregnancy. Indeed, that is the only justification of developing such a complex procedure.

I have some reservations over this issue. Granted that these infants do survive to term and are delivered from the womb, what evidence is there to predict how they will behave after this ? Survival also means how long they will live, and with what quality of life. My concerns are in three areas.

• First, are we intervening in a "genetically weak" subset of fetuses ? Many more undetectable anomalies involving other systems may coexist, which in their own right will reduce survival. Correcting the "fatal" heart defect will "unmask" them. We may then end up with poor long term survival from non-cardiac causes.

• Second, what about complications introduced by the procedure itself ? Neurologic complications - involving the brain and nerves - are particularly tragic. Would it be justified to deliver a infant with a repaired heart, but accept a damaged brain as the price of this ?

• And third, what if these complications are not fatal, but proved disabling nonetheless ? We would then be faced with a population of "walking wounded". Who should make decisions about the level of intensive care to be extended to these unfortunate survivors ?

Many issues thus remain to be thrashed out in the experimental lab, as well as in medical, surgical, ethical and religious fora regarding similar issues. It is time the concerned bodies take cognizance of the impending arrival of fetal cardiac surgery on the clinical scene, and prepare themselves in all ways.

Next week : Terminate the pregnancy ?