Babies in whom a heart defect was diagnosed before birth were more likely to survive initial surgery to correct the defect than those in whom a defect was diagnosed after birth, a new study has shown. Only two thirds of those with a postnatal diagnosis survived.
Dr Wayne Tworetzky, lead investigator of the study, said: "This is the first study to demonstrate that patients diagnosed prenatally with hypoplastic left heart syndrome have improved survival after the first stage of surgery compared to those diagnosed after birth" (Circulation 2001;103:1269-73).
Dr Tworetzky is a clinical instructor in the cardiology department at Boston Children's Hospital. The study, which used standard prenatal ultrasound, was carried out at the University of California, San Francisco.
Previous studies did not show a significant benefit, but Dr Tworetzky said that these were smaller and may not reflect recent medical advances in managing such cases. This study dealt with 88 infants in whom the condition was diagnosed at the university between July 1992 and March 1999: it was diagnosed prenatally in 33 cases and postnatally in 55. Only 52 of the babies underwent surgery, and the survival rate among those with a prenatal diagnosis was higher than among the rest.
In the heart condition studied, the left side of the heart is underdeveloped and unable to support blood circulation after birth. Without treatment, babies with this defect usually die within the first few days of life. Treatment entails a series of operations.
Dr Tworetzky said that prenatal diagnosis affords time for physicians both to counsel parents and to optimise early treatment, which allows the infant to be in the best condition for surgery. Without the benefit of prenatal diagnosis, many babies with this condition are born in a facility that is not equipped to care for them.
He said: "The delay in diagnosis may lead to the infant going into shock or suffering multiple organ damage among other complications--all of which limit the success of the initial surgery ... The normal changes that occur in the newborn infant's circulatory system shortly after birth are not well tolerated by these infants. The first operation is the most difficult and carries the highest risk of death."
Overall survival from surgery to hospital discharge was 75%, but all of the babies with a prenatal diagnosis survived to discharge. Those with a postnatal diagnosis were generally more ill before going into surgery and had poorer outcomes after surgery: about 66% survived the surgery.
Among the 52 infants who underwent surgery, those with a prenatal diagnosis also had a significantly lower incidence of preoperative lactic acidosis. These babies also had lower rates of ventricular dysfunction and were significantly less likely to need drugs for resuscitation before the operation.
Although hypoplastic left heart syndrome is one of the most common cardiac defects found prenatally, Dr Tworetzky said that it is still common for the condition to be diagnosed after birth. The mothers of most babies with a postnatal diagnosis in this study had not undergone routine prenatal ultrasound screening. There are no known risk factors or genetic causes for the condition, but research is under way to fred possible genetic links.
David Spurgeon Quebec
COPYRIGHT 2001 British Medical Association
COPYRIGHT 2001 Gale Group
Contact
Home
A
Hairy cell leukemia