For more than a decade, University of Miami researcher Steven E. Lipshultz led a national team of pediatric specialists trying to solve a medical mystery that had proved fatal for its youngest victims: Why did some children suffering from hypertrophic cardiomyopathy die of heart failure or sudden cardiac death while others didnt?
Lipshultz untangled part of that complex riddle and published his findings online earlier this month in the medical journal The Lancet, giving hope to thousands of families whose children live with this rare disease. His team discovered that infants under a year old with certain subtypes of the chronic heart ailment were more at risk of death than children who were older.
What may seem like a small difference is actually very important. Lipshultz developed a risk calculator that classifies the risk factors and provides guidelines to predict outcomes for patients. This will help pediatric heart specialists determine a childs need for an immediate heart transplant.
Before these findings, children under a year old with pediatric hypertrophic cardiomyopathy a disease in which the heart muscle deteriorates and cant supply the body with enough blood were not put on transplant lists. Yet, Lipshultz found that if these infants exhibited two or more risk factors at diagnosis, they had the lowest survival rate of all pediatric HCM patients and were prime candidates for a transplant. (Risk factors that worsened infants prognoses include low weight or body mass index, congestive heart failure, abnormal echocardiographic measure, genetic metabolism disorders and mixed types of cardiomyopathy.)
Most older kids with HCM, however, survived. The study showed that 97 percent of children diagnosed after their first birthday could be treated conventionally and had excellent outcomes, transplant free.
This is a step in the right direction because predicting the outcome for children with HCM has been very difficult, said Lipshultz, director of the Batchelor Childrens Research Institute at UMs Miller School of Medicine. HCM has many causes and symptoms, and the causes, in turn, have very different outcomes. Before this we didnt know which factors were more important in predicting those outcomes.
Lipshultz and his team analyzed more than 1,000 cases from 98 medical centers in the United States and Canada. The cases, enrolled over a 19-year period in the Pediatric Cardiomyopathy Registry, which Lipshultz founded in 1994, gave researchers enough material to analyze patterns. This would have been impossible to do without the registry because individual pediatric care centers see few patients with HCM.
Hypertrophic cardiomyopathy is one of five forms of the chronic heart ailment. About 30,000 children in the United States are living with some form of cardiomyopathy that is either inherited or acquired later in life. Studies show that children are about 10 times more likely to develop it during their first year than during ages 2 to 18. Depending on the type and the stage of the disease, symptoms can vary. These include shortness of breath, chest pain, fatigue, irregular heartbeats, dizziness, lightheadedness, swelling of the legs, ankles and feet, and abdominal bloating.
There is no cure, but the disease is treatable by medications, surgery, implantable defibrillators and, in extreme cases, with heart transplants.