In Vitro Hemolytic Performance of the Realheart® V11C TAH Prototype with Porcine Blood

BACKGROUND

Hemolysis testing of new devices to treat heart failure is a regulatory requirement. The ASTM F1841-97 standard for hemolysis testing was developed for continuous flow pumps and does not specify test rig design. When research groups use different methodologies, results are difficult to compare. Pulsatile flow pump rigs require compliance chambers, thus the Aachen rig (Gräf et al) was developed for the pulsatile Reinheart TAH. The study objective was to use this rig to test the early Realheart TAH prototype V11C hemolysis performance compared to literature.

METHODS

The experimental control was the continuous flow pump BPX-80 (Medtronic) and pooled heparinized porcine blood was used.

RESULTS

The mgNIH of BPX-80 and V11C was 5.42 ± 1.47 and 25.20 ± 5.46 mg/100 L, respectively. The NIH ratio of V11C over BPX-80 was 5.5.

CONCLUSION

The absolute and the relative hemolysis of the V11C are lower compared to both the large and small Reinheart TAH devices published values. Pulsatile pumps create more hemolysis in the Aachen rig, and it is not known if this is because how the rig handles pulsatile flow or due to the devices. Future studies will therefore use a pulsatile pump such as the SynCardia as clinical comparator and human blood to test the performance of future Realheart TAH prototypes.

Success of Thrombectomy in Management of Ischemic Stroke in Two Patients with SynCardia Total Artificial Heart in Bridge-to-Transplantation

Introduction: Circulatory assistance from a SynCardia Total Artificial Heart (SynCardia-TAH) is a reliable bridge-to-transplant solution for patients with end-stage biventricular heart failure. Ischemic strokes affect about 10% of patients with a SynCardia-TAH. We report for the first time in the literature two successful thrombectomies to treat the acute phase of ischemic stroke in two patients treated with a SynCardia-TAH in the bridge-to-transplant (BTT). Case report: We follow two patients with circulatory support from a SynCardia-TAH in the bridge-to-transplant for terminal biventricular cardiac failure with ischemic stroke during the support period. An early in-hospital diagnosis enables the completion of a mechanical thrombectomy within the first 6 h of the onset of symptoms. There was no intracranial hemorrhagic complication during or after the procedure and the patients fully recovered from neurological deficits, allowing a successful heart transplant. Conclusion: This case report describes the possibility of treating ischemic strokes under a SynCardia-TAH by mechanical thrombectomy following the same recommendations as for the general population with excellent results and without any hemorrhagic complication during or after the procedure.

Total artificial heart in the pediatric patient with biventricular heart failure

Mechanical circulatory support emerged for the pediatric population in the late 1980s as a bridge to cardiac transplantation. The Total Artificial Heart (TAH-t) (SynCardia Systems Inc., Tuscon, AZ) has been approved for compassionate use by the Food and Drug Administration for patients with end-stage biventricular heart failure as a bridge to heart transplantation since 1985 and has had FDA approval since 2004. However, of the 1,061 patients placed on the TAH-t, only 21 (2%) were under the age 18. SynCardia Systems, Inc. recommends a minimum patient body surface area (BSA) of 1.7 m(2), thus, limiting pediatric application of this device. This unique case report shares this pediatric institution's first experience with the TAH-t. A 14-year-old male was admitted with dilated cardiomyopathy and severe biventricular heart failure. The patient rapidly decompensated, requiring extracorporeal life support. An echocardiogram revealed severe biventricular dysfunction and diffuse clot formation in the left ventricle and outflow tract. The decision was made to transition to biventricular assist device. The biventricular failure and clot formation helped guide the team to the TAH-t, in spite of a BSA (1.5 m(2)) below the recommendation of 1.7 m(2). A computed tomography (CT) scan of the thorax, in conjunction with a novel three-dimensional (3D) modeling system and team, assisted in determining appropriate fit. Chest CT and 3D modeling following implantation were utilized to determine all major vascular structures were unobstructed and the bronchi were open. The virtual 3D model confirmed appropriate device fit with no evidence of compression to the left pulmonary veins. The postoperative course was complicated by a left lung opacification. The left lung anomalies proved to be atelectasis and improved with aggressive recruitment maneuvers. The patient was supported for 11 days prior to transplantation. Chest CT and 3D modeling were crucial in assessing whether the device would fit, as well as postoperative complications in this smaller pediatric patient.