Berlin Heart EXCOR® pediatric

Johannes Müller
Chief Scientific and Medical Officer, Berlin Heart GmbH
Berlin, Germany

Weaning from cardiac support by a mechanical assist device is the ideal outcome after placement of such a system in patients with heart failure. Heart transplantation becomes redundant. However, despite intensive research there is no predictive parameter available which allows a decision in favour for weaning before placement of a device. Derived from an increasing experience made during the last 10 to 15 years some general statements can be given and seem to be plausible.
　Precondition for weaning is unloading of the heart. Unloading reduces the inflammatory status of the myocardium. Weaning is most likely if the remodelling process of the myocardium and in particular of the extracellular matrix is unincisive or the acute damage is reversible. This in turn has something to do with the duration of heart failure or in patients with acute heart failure (postcardiotomy; acute myocarditis) with the degree of the destruction of the myocardial structure.
　In children there are two aspects to be taken into account. On one hand the remodelling process runs definitely faster than in adults on the other hand the potential for a reverse remodelling is more pronounced. In clinical practice, this experience has to be translated into an early implantation of a device with a significant unloading of the heart, because only by the unloading of the heart the remodelling process can be interrupted and the reverse remodelling process (recovery) can be initialised.
　Though the implantation of an ECMO system leads to maintenance of the circulatory condition of the patients, ECMO does not unload the heart to a significant extent.
　Criteria for weaning are the significant improvement of the hearts function to near normal values measured by echo examination. Main parameters are ejection fraction, internal diameter of the left ventricle, wall motion velocity in systole, strain rate and the geometry of the left ventricle.
　According to available data approximately 25 percent of children with myocarditis can be weaned, about 30 percent with ischemic heart disease, 20 percent with postcardiotomy syndrome, and 40 percent by post heart transplantation.
　To conduct a successful weaning procedure the weaning process has to be performed after a protocol derived from experience in the last couple of years. The main focus of this protocol is to find the right balance between unloading, over unloading and loading of the heart by the adjustment of the pump.
　Considering all the available weaning experience in children one can state that the unloading of the heart on time (early) is most likely the key for success and a high number of weaned patients after placement of a device.