Many children who develop acute viral myocarditis present to their care team in shock or in impending shock. They frequently have poor circulation, weak or “thready” pulses, and irregular heart rhythms. Their other organs such as the kidney, liver and lungs may also be weakened or injured. These patients are at greatest risk of cardiovascular collapse and death.
Fortunately, mechanical circulatory support (MCS) devices may allow doctors and surgeons to save the lives of children with advanced heart failure caused by myocarditis. A MCS device is a type of artificial heart pump that is inserted into the patients’ blood vessels and/or directly into the heart. Basically, it takes over the work of the heart, pumping blood to the body and providing adequate circulation to the failing organs. It also unloads the heart, allowing it to rest and heal while the viral infectious process resolves. Dr. Ivan Wilmot, and others from Texas Children’s Hospital in Houston, reported on their experience using MCS in children with acute or persistent myocarditis. They treated 16 children with MCS. Of those patients, 12 of 16 (75%) survived: 5 went on to develop complete recovery of their heart function and 7 were successfully “bridged” to cardiac transplantation. These findings provide further evidence that patients can survive even severe myocarditis if diagnosed and treated in a timely manner. The Houston medical team speculated that MCS allows physicians and surgeons a new way to think about treating acute myocarditis in children.
In a separate multi-institutional study of 15 children supported with MCS, Dr. Brian Duncan reported that 80% of patients survived. Seven out of 9 patients who were weaned from the MCS support remained alive at a median time of 1.1 years, ranging from 0.9 to 5.5 years after undergoing surgery.
Awareness of the potential recovery of heart function in children with myocarditis, plus the ability to save lives with MCS devices, has fostered an urgency to create more miniaturized versions of heart pumps that can allow for better and safer support of the circulation in small patients. The National Heart, Lung and Blood Institute Institute has awarded funding to develop a heart pump suitable for supporting the circulation of children as small as infants. The Infant Jarvik 2000 is about to enter the clinical research phase and will be studied through 2018. The pump, about the length of a paper clip, can be used in children as small as 4kg (~9 lbs).