Andersons pediatric cardiology 1756

Current Devices for Short-Term Mechanical Circulatory Support in Pediatrics Extracorporeal membrane oxygenation (ECMO) has been the primary means of short-term MCS for many years due to its familiarity and ease of rapid deployment Although ECMO is useful in certain circumstances such as the need for emergent support or simultaneous pulmonary support, throughout its 25 years of use we have yet to see significantly more than half the cardiac patients survive to hospital discharge reported in multiinstitutional studies Furthermore, ECMO as a bridge to transplant is a well-established independent risk factor for posttransplant mortality.20 For isolated heart failure, other forms of short-term MCS have been developed and are preferred in most situations Historically, adult short-term left VADs (LVADs) (e.g., BVS 5000) were occasionally used in larger children, with cannula and device size/output being factors limiting their widespread use Currently, temporary devices are extracorporeal centrifugal pumps used with cardiopulmonary bypass cannulas, such as the ROTAFLOW (Maquet Cardiovascular) and the CentriMag/PediMag (Abbott) These centrifugal pumps are now found in most pediatric ECMO programs and therefore are familiar and accessible to the vast majority of pediatric heart programs Another pump, the TandemHeart (CardiacAssist), has percutaneously placed cannulas to the left atrium and femoral artery, whereas the Impella (Abiomed) is a percutaneous, rotary heart pump that sits across the aortic valve in the left ventricular outflow tract Both devices, especially the TandemHeart, require adolescent-sized, if not adult-sized, children Cannula movement with minimal patient manipulation requiring cannula repositioning makes the use of the TandemHeart in smaller patients quite challenging Until recently, there was a paucity of pediatric data regarding the outcomes of temporary devices and support, but studies are beginning to accumulate The notion of temporary support revolves around a quick and simple cannulation strategy meant to briefly sustain cardiac output (CO) in a patient with a reversible cause of heart failure or in urgent need of MCS For temporary support, the left atrium can be rapidly cannulated along with the aorta, using bypass cannulas and without the need for cardiopulmonary bypass This strategy is useful for patients with severe graft rejection or fulminant myocarditis so that perfusion is normalized and end-organ function is supported until the inflamed state of the heart can resolve and function can, hopefully, return The device can then be removed However, it can also be used to get a patient out of INTERMACS 1 so they become a better long-term support candidate or in a patient who needs support to allow time to determine etiology of heart failure, neurologic status, genetic issues, and so forth as a bridge to decision The PediMag and ROTAFLOW have historically been synonymous with temporary support and were connected to patients with bypass cannulas in a temporary cannulation configuration However, in the past few years, surgeons have begun connecting the same device pumps to EXCOR cannulas as a bridge to transplantation This is significantly different because EXCOR cannula placement is a more permanent cannulation technique requiring a more involved surgery and cardiopulmonary bypass By virtue of using EXCOR cannulas with a pump, these devices are no longer used only as a means of temporary support because it is the cannulas that determine the duration for which support can be provided, not the pump itself This combination of EXCOR cannulas with CF pumps is being done as a bridge to transplant in smaller children to simplify management of their anticoagulation during their postoperative inflammatory state Furthermore, centrifugal pumps may require a lower level of anticoagulation, but if they do become thrombosed, they are easier and cheaper to replace Once the patient stabilizes, the pump can be exchanged for an EXCOR pump to increase patient mobility if desired A similar strategy is becoming the standard of care for smaller patients (