Jeffrey A. Morgan and Yoshifumi Naka (eds.)Surgical Treatment for Advanced Heart Failure201310.1007/978-1-4614-6919-3_15© Springer Science+Business Media New York 2013
15. Ventricular Assist Devices and Transplantation for Adults with Congenital Heart Disease
Department of Pediatrics and Cardiothoracic Surgery, New York Presbyterian Hospital, Cornell Campus, 525 E. 68th Street, Suite M404, New York, NY 10023, USA
Division of Cardiothoracic Surgery, Department of Surgery, New York Presbyterian Hospital, Columbia Campus, 177 Fort Washington Ave., Milstein Hospital Building, Room 7GN-435, New York, NY 10023, USA
Patients with congenital heart disease pose a unique challenge to the transplant surgeon often due to prior complex reconstructive procedures and/or abnormalities in systemic and pulmonary venous return. Options for mechanical assistance of advanced heart failure in this population as well as considerations regarding operative technique required at the time of cardiac transplant are discussed.
While corrective surgery for congenital heart lesions generally obviates the need for further operative repairs, concurrent cardiomyopathy, acquired ischemic damage, and progressive failure of the systemic ventricle can all too often lead to end-stage heart failure in this complex cohort. While the principles of ventricular assist device (VAD) support or transplantation in these settings are no different than for those patients with dilated cardiomyopathy, prior palliative procedures, the presence of progressive aortopulmonary collaterals, and the existence of multiple prior operations significantly complicate later mechanical ventricular assistance and transplantation. In this setting, surgical flexibility and creativity are essential to adjust to the challenges of anatomy and physiology that the adult with congenital heart disease presents.
The most common indications for mechanical ventricular assistance in adults with congenital heart disease are progressive concurrent cardiomyopathy, the failing systemic right ventricle, and the failing Fontan. While most adult patients with congenital disease are closely followed throughout their lifetime, “acquired” cardiomyopathy and heart failure may represent the cumulative insult of several prior operative repairs, progressive ischemic damage, or ongoing volume overload from aortopulmonary collaterals on myocardium that is inherently abnormal (e.g., noncompaction). In patients with corrected transposition of the great vessels (ccTGA), an additional sustained risk of complete heart block may contribute substantially to this progression. The failed Fontan candidates, incomplete volume unloading, significant atrioventricular valve regurgitation, malignant atrial tachyarrhythmias, and significant cyanosis or ascites in aggregate contribute significant risk to any such procedure.
The tenets of mechanical support in this setting, then, must address several key questions. First, is the indication for support short or long term—is this supportive therapy for the patient with ccTGA until they can be properly paced (with uni- or biventricular pacing), or is this an adult with a Mustard or Senning whose right ventricle has finally decompensated and is unsalvageable? Second, will the mechanical assistance address the problem? Single ventricular support of the failing Fontan will not necessarily improve oxygenation, in particular because of the ongoing need for passive pulmonary blood flow. In such a situation, extracorporeal membrane oxygenation (ECMO) therapy may be most appropriate. Creative solutions for assistance of pulmonary arterial flow may also actually be what is required if the ventricular function is reasonable.
Third, in the presence of prior repairs, is the proposed assistance feasible? A patient with a Mustard/Senning who requires biventricular support will present unique challenges to obtain right ventricular assist device (RVAD) inflow, given the location and orientation of the systemic venous baffle. The extensive trabeculations within a systemic right ventricle may increase the risk of obstruction of the inflow cannula if not properly resected. Creative solutions to single ventricular support through a previously unused approach (e.g., thoracotomy) must take into account ventricular looping and apical directionality (e.g., dextrocardia). Additionally, those with right ventricular to pulmonary artery conduits generally have such severe calcification of the prior conduit that cannulation for RVAD outflow would be nearly impossible. Fourth, does the anatomy demand a particularly creative approach? Although rare, situs inversus totalis unsurprisingly requires significant changes in the location and choice of cannulation, as does dextrocardia, mesocardia, and situs ambiguous. In these cases, the preoperative evaluation with cardiac catheterization, magnetic resonance imaging (MRI), and computed tomography (CT) scan is of utmost importance.
An essential question is also whether the patient would best be served with one of several less traditional options. The most common of these is ECMO, which can often be approached percutaneously and/or peripherally. As with ECMO for any other indication, it will be less effective in the presence of moderate or severe aortic (or neoaortic) valve regurgitation. If ECMO is being pursued in the presence of an intact atrial septum, it must be remembered that this therapy will not completely decompress the systemic ventricle, which is of pertinence if ventricular recovery is being considered. For these patients, a blade septostomy may allow for capture of pulmonary venous return, as may an additional pulmonary artery catheter. However, for those with significant aortopulmonary collaterals, only inflow from a site distal to the left atrium will afford adequate drainage and decompression of the systemic ventricle. Ultimately, however, ECMO requires intubation and sedation, with no realistic hope for extubation or mobilization; for an adult with a projected long waiting time to transplantation, this may not be a viable therapeutic strategy.
A new option that is also for short to medium term (days to weeks) use is represented by new percutaneous support devices. We have used RVAD support with two percutaneous venous cannulae (BioMedicus centrifugal pump, Medtronic Inc, Minneapolis, MN) in the right atrium (via right internal jugular) and main pulmonary artery (via femoral venous access) with a centrifugal pump for RVAD or ECMO support, in concert with an Impella 2.5 (Abiomed, Danvers, MA) device for partial ventricular support in a teenager with fulminant transplant rejection. Here, the risks of hemorrhage and infection from reoperative sternotomy and the potential need for an open chest are obviated, but again the duration of support is somewhat limited. Other devices that have been considered in this realm are the TandemHeart (Cardiac Assist, Pittsburgh, PA) and other percutaneous assist devices under current investigation. The possibility of a full-flow device (e.g., Impella 5.0) for adult sizes may make this particular strategy more appealing in the future.