During the past 6 years, we have been developing and testing various technological iterations for total heart replacement in our animal laboratory and have achieved survival periods as long as 90 days in calves. We describe the development, preclinical trials, and adaptation for human use of the modified HeartMate II apparatus, as well as its role in our patient's survival.

We implanted a continuous-flow total heart replacement device in a 55-year-old man who had severe end-stage heart failure due to amyloidosis and no other options for treatment. The device was composed of 2 modified HeartMate II ventricular assist pumps. After the implantation, our patient recovered normal neurologic function and was able to converse with his family and work on his computer. He died of multisystem organ failure caused by severe amyloidosis 5 weeks after the implantation.

During the past 6 years, we have been developing a continuous-flow device to totally replace the failing heart. The device, composed of 2 continuous-flow ventricular assist devices, has been subjected to extensive in vivo testing, with survival periods as long as 90 days in calves. In March 2011, we first used a similar device to replace the heart of a man who had refractory heart failure due to amyloidosis. The patient had no other treatment options. We describe this device's development, preclinical trials, adaptation for human use, and role in the patient's survival.

Case Report

A 55-year-old man was admitted to our institution in February 2011. He had rapidly progressive end-stage heart failure due to amyloidosis, which was confirmed histologically ( ). Intra-aortic balloon pump counterpulsation and intravenous inotropic therapy were unsuccessful in restoring adequate circulation. The patient had to be intubated because of progressive respiratory distress and was undergoing continuous hemodialysis for anuric renal failure. At that point, we decided to try extra-corporeal circulatory assistance with use of a TandemHeart® (CardiacAssist, Inc.; Pittsburgh, Pa). A transseptal 21F left atrial cannula was placed percutaneously via the right femoral vein, and a 17F cannula was placed via the left femoral artery. Because of severe right ventricular compromise, only 3 L/min of flow was attainable with the device. Despite multiorgan failure, the patient's neurologic function remained intact. An echocardiogram obtained after 2 weeks of TandemHeart support showed a small, akinetic-restricted heart and no evidence of myocardial recovery.

Options were limited for this gravely ill patient, partially because of his small physical stature (height, 175.3 cm; weight, 63.2 kg). However, we thought that he might be a candidate for heart and bone marrow transplantation if his other organs could recover enough function.1 Emergent cardiac transplantation was not considered, not only because of the logistical unlikelihood of finding a donor but also because the patient's critical condition would have made post-transplantation survival unlikely.

Use of a left or right ventricular assist device was considered for intermediate-term circulatory support. However, the patient's extremely thickened and stiff left ventricular (LV) wall and small, contracted LV cavity were contraindications to LV assist device placement. In such patients, obtaining an unobstructed inlet-cannula position is extremely difficult. In addition, the patient's small body habitus and hepatomegaly greatly limited the space available for an implantable subdiaphragmatic pump, necessitating paracorporeal device placement. The Syn Cardia CardioWest® pneumatically actuated total artificial heart (SynCardia Systems, Inc.; Tucson, Ariz) was also not an option: the patient had a narrow chest cavity, and suturing the device to the stiff amyloid-infiltrated rim of ventricular muscle would have been a technical challenge. For this second reason, advanced cardiac amyloidosis is a contraindication to the use of the SynCardia pump. We finally decided to replace his heart with 2 HeartMate® II axial-flow pumps (Thoratec Corporation; Pleasanton, Calif) that would function as a continuous-flow total heart replacement. To achieve this, we used customized atrial adapters that we had developed for use with the HeartMate II blood pumps during the preceding 6 years of extensive in vitro and in vivo preclinical studies.

The Continuous-Flow Total Heart Replacement Device The 2 atrial adapters used in this case were fabricated from knitted polyester Vascutek® Gelseal™ cardiovascular patches (Terumo Cardiovascular Systems Corporation; Ann Arbor, Mich) that were reinforced with 4 layers of 10 × 14-in polypropylene hernia repair mesh (C.R. Bard, Inc.; Murray Hill, NJ). The adapters were impregnated with medical-grade silicone adhesive and subjected to both ethylene-oxide and steam sterilization. Each polyester patch was fashioned into a cone of proper dimension (20° at the apex) by using a single hand-sewn line of 5-0 polypropylene suture. Each polyester cone was then placed over a solid plastic mandrel to hold the conical geometry while the outer layers were reinforced with the polypropylene hernia mesh and medical silicone adhesive. When the adhesive had dried, the cones were removed from the mandrels, and the apex of each cone was excised at a sharp angle. The resulting elliptical opening was then measured, and an elliptical patch of the same dimensions was fashioned from mesh-reinforced polyester. A round hole, 14 mm in diameter, was then cut in each elliptical patch close to one end to accommodate the HeartMate II inflow after removal of the inflow cannulas.