The SynCardia Temporary Total Artificial Heart—Evolving Clinical Role and Future Status
US Cardiology Review
Heart failure remains the final common pathway of all forms of heart disease. Currently, more than 20 million patients suffer with heart failure in the US and Europe combined. 1 Over the past two decades, advances in medical therapeutics have made inroads in reducing mortality associated with early-and mid-stage heart failure. Unfortunately, once patients progress to advanced heart failure, i.e. American Heart Association (AHA) stage D, New York Heart Association (NYHA) class IV, they face
... IV, they face progressive and near-certain mortality. It is estimated that nearly 100,000 patients have advanced heart failure in the US. For these patients a 'pump' is needed to countervail circulatory failure, either in the form of a human heart transplant or a mechanical prosthetic device. The SynCardia temporary Total Artificial Heart (TAH) is the only TAH, despite 40 years of research and development by many groups, that has successfully passed the hurdles of rigorous clinical trials, US Food and Drug Administration (FDA) pre-market regulatory approval (PMA), and Centers for Medicare and Medicaid Services (CMS) reimbursement. 2,3 In this article the evolving role and future status of the SynCardia TAH will be discussed. Specifically, the following issues will be covered: (i) advantages of the TAH relative to ventricular assist devices (VADs); (ii) a summary of TAH clinical experience; (iii) indications for TAH use and selection considerations; (iv) TAH technology advances-enhanced mobility, home discharge, remote monitoring, and next-generation designs; and (v) the growing need for the TAH. Advantages of the Total Artificial Heart Relative to Ventricular Assist Devices In the rapidly advancing field of mechanical circulatory support (MCS) it is becoming clear that there is need for a spectrum of devices able to address the varying degrees of cardiac dysfunction that are encountered in advanced heart failure. To date, a wide range of devices has been developed with varying pump capabilities, ranging from partial support, to ventricular assist, to full replacement. The SynCardia TAH is the only effective device in use in the world today that is capable of providing full cardiac replacement. If we examine MCS devices from the perspectives of intrinsic design, laboratory testing, and clinical trials, specific device features emerge that are distinctive and beneficial. From this perspective, the TAH has several unique features that are advantageous relative to VADs. The SynCardia TAH is a bi-ventricular pneumatic pulsatile pump consisting of three components: prosthetic ventricles (two), drivelines, and an external pneumatic driver (see Figure 1) . Details of the TAH have been extensively described. 4 Recently, several major Abstract The SynCardia Temporary Total Artificial Heart (TAH) is the only clinically effective, Conformité Européene (CE) registered, Food and Drug Administration (FDA) approved and Centers for Medicare and Medicaid Services (CMS) reimbursed total artificial heart system available in the world today. The TAH is a complete, robust, pulsatile, biventricular replacement system indicated for use as a bridge to transplantation in cardiac transplant candidates at risk of imminent death from non-reversible biventricular failure. The TAH offers several advantages relative to present continuous flow left ventricular assist devices (LVADs), including higher 'quality' flow rates, reduced afterload and preload sensitivity, reduced thrombosis and stroke rates, and freedom from device-induced bleeding. More than 900 TAHs have been implanted to date, with a bridge-to-transplant success rate >79%. The availability of the new portable Freedom ® driver has significantly enhanced patient mobility and made home discharge of patients possible. With home discharge, significant experience with long-term support on the TAH is now beginning to be accumulated. Technological advances continue to be imparted to the TAH system including portable driver enhancements, remote monitoring, and next-generation TAH designs.