Switch from Assist Device to Total Artificial Heart to Improve Cardiac Output

Case Report

Left ventricular assist devices (LVADs) are an integral part of the therapeutic scenario in end-stage congestive heart failure as a bridge to heart transplantation, bridge to recovery or as a destination therapy [1], [2], [3]. The development of small size assist devices such as the free floating axial impeller pump InCor, (BerlinHeart, Berlin, Germany) has been a big step forward in terms of reducing the extent of the surgical intervention and allowing the patient a maximum of mobility. However, the maximum cardiac output of such free floating axial impeller pumps is limited, and for some patients a system offering a greater output such as the CardioWest total artificial heart (SynCardia Inc., Tucson, AZ, USA) may be beneficial [4], [5].

A 30-year-old male patient (height 188 cm, weight 125 kg, body surface area 2.49 m²) with a known history of idiopathic dilative cardiomyopathy was admitted to our department with recurrent manifestations of cardiac decompensation despite optimal heart failure medication and cardiac resynchronization therapy. Echocardiography revealed a severely dilated left ventricle (end-diastolic diameter 10.9 cm, end-diastolic volume 717 ml) and an ejection fraction of 11 % plus a mild aortic valve insufficiency in the presence of regular diastolic blood pressures. The right ventricular systolic pressure was 56 mmHg, and pulmonary vascular resistance was about 3 Wood units. The patient could be stabilized by use of β-mimetics. After consideration of the patient's clinical condition, the primary goal was heart transplantation. However, an increase in listing criteria to give him a high urgency status was repeatedly rejected by Eurotransplant (Leiden, The Netherlands) due to pulmonary artery hypertension and considerably elevated body weight. Therefore, an InCor LVAD was implanted in order to reduce pulmonary artery pressures and to give the patient time to reduce his body weight. Implantable pulsatile devices of the Novacor (WordHeart Inc., Oakland, CA, USA) or HeartMate (Thoratec Corp., Pleasanton, CA, USA) type are no longer used in our department. Due to the long waiting time until cardiac transplantation of around 300 days we did not choose an extracorporeal device. The operation was performed without complications, but the patient showed a considerably delayed recovery in the intensive care unit. The LVAD speed was increased to a maximum of 8000 rounds per minute to achieve a cardiac output of about 5 l/minute. Unfortunately, typical signs of hemolysis appeared with a higher flow. With a LVAD flow of 5 l/min the patient could not achieve the desired mobilization and remained in intensive care for 2 months. Finally, he developed signs of a low output syndrome with the need for inotropic support and renal replacement therapy. In addition, right heart failure also occurred. An additional right ventricular assist device would have solved the problem of the right heart failure but not the low output syndrome of the left heart. Therefore, the decision was made to switch to a total artificial heart (TAH) ([Fig. 1]), which would allow the cardiac output to be increased to about 8 l/min. Intraoperatively, both ventricles were severely dilated with impaired contractions. After preparation, both ventricles were excised at the atrioventricular level. The trimmed atrial cuffs were anastomosed and the outflow grafts were connected to the aorta and pulmonary artery. Following implantation of the TAH the clinical situation improved quickly. The elevated liver enzymes returned to normal levels and kidney function improved soon after the implantation. The patient is now at home and is on the waiting list for heart transplantation. His body weight is reducing continuously following a dietary plan.

Fig. 1 a to d Switch from LVAD to a total artificial heart: 30-year-old patient with an InCor LVAD (a Chest X‐ray, b InCor during explantation). After 2 months the InCor LVAD was switched to a total artificial heart (CardioWest) because a higher cardiac output was required (c Chest X‐ray, d CardioWest during implantation).

References

• 1 Schmid C, Tjan T D, Etz C. et al . First clinical experience with the InCor left ventricular assist device.  J Heart Lung Transplant. 2005;  24 1188-1194
• 2 Schmid C, Tjan T, Etz C. et al . The Excor device – revival of an old system with excellent results.  Thorac Cardiovasc Surg. 2006;  54 393-399
• 3 Birks E J, Tansley P D, Hardy J. et al . Left ventricular assist device and drug therapy for the reversal of heart failure.  N Engl J Med. 2006;  355 1873-1884
• 4 Copeland J G, Smith R G, Arabia F A. et al . CardioWest total artificial heart investigators. Cardiac replacement with a total artificial heart as a bridge to transplantation.  N Engl J Med. 2004;  351 859-867
• 5 Copeland J G, Arabia F A, Tsau P H. et al . Total artificial hearts: bridge to transplantation.  Cardiol Clin. 2003;  21 101-113