EVAHEART 2 with double cuff tipless inflow cannula is suitable for long-term support atrial switch operation in transposition of great arteries.

Implantation of continuous-flow left ventricular assist device in a narrow lumen is technically challenging to secure an optimal support. We experienced a patient with the transposition of the great arteries after the Senning procedure who was initially implanted with Jarvik 2000®. She presented with worsening heart failure symptoms 2 years after implanting Jarvik 2000®. We assumed that the inflow cannula was stuck in the highly developed trabeculae on the interventricular septum, which disturbed the VAD to maintain an expected support. After converting to the EVAHEART® 2, we successfully obtained an adequate inflow. We consider that the tipless cannula of EVAHEART® 2 is the most suitable when there is no sufficient room to place a conventional inflow cannula in the systemic ventricle.

Influence of a Rotational Speed Modulation System Used With an Implantable Continuous-Flow Left Ventricular Assist Device on von Willebrand Factor Dynamics.

We have developed a rotational speed (RS) modulation system for a continuous-flow left ventricular assist device (EVAHEART) that can change RS in synchronization with a patient's electrocardiogram. Although EVAHEART is considered not to cause significant acquired von Willebrand syndrome, there remains a concern that the repeated acceleration and deceleration of the impeller may degrade von Willebrand factor (vWF) multimers. Accordingly, we evaluated the influence of our RS modulation system on vWF dynamics. A simple mock circulation was used. The circulation was filled with whole bovine blood (650 mL), and the temperature was maintained at 37 ± 1°C. EVAHEART was operated using the electrocardiogram-synchronized RS modulation system with an RS variance of 500 rpm and a pulse frequency of 60 bpm (EVA-RSM; n = 4). The pumps were operated at a mean flow rate of 5.0 ± 0.2 L/min against a mean pressure head of 100 ± 3 mm Hg. The continuous-flow mode of EVAHEART (EVA-C; n = 4) and ROTAFLOW (ROTA; n = 4) was used as controls. Whole blood samples were collected at baseline and every 60 min for 6 h. Complete blood counts (CBCs), normalized indexes of hemolysis (NIH), vWF antigen (vWF:Ag), vWF ristocetin cofactor (vWF:Rco), the ratio of vWF:Rco to vWF:Ag (Rco/Ag), and high molecular weight multimers (HMWM) of vWF were evaluated. There were no significant changes in CBCs throughout the 6-h test period in any group. NIH levels of EVA-RSM, EVA-C, and ROTA were 0.0035 ± 0.0018, 0.0031 ± 0.0007, and 0.0022 ± 0.0011 g/100 L, respectively. Levels of vWF:Ag, vWF:Rco, and Rco/Ag did not change significantly during the test. Immunoblotting analysis of vWF multimers showed slight degradation of HMWM in all groups, but there were no significant differences between groups in the ratios of HMWM to low molecular weight multimers, calculated by densitometry. This study suggests that our RS modulation system used with EVAHEART does not have marked adverse influences on vWF dynamics. The low NIH and the absence of significant decreases in CBCs indicate that EVAHEART is hemocompatible, regardless of whether it is operated with the RS modulation system.

Pulsatile support using a rotary left ventricular assist device with an electrocardiography-synchronized rotational speed control mode for tracking heart rate variability.

We previously developed a novel control system for a continuous-flow left ventricular assist device (LVAD), the EVAHEART, and demonstrated that sufficient pulsatility can be created by increasing its rotational speed in the systolic phase (pulsatile mode) in a normal heart animal model. In the present study, we assessed this system in its reliability and ability to follow heart rate variability. We implanted an EVAHEART via left thoracotomy into five goats for the Study for Fixed Heart Rate with ventricular pacing at 80, 100, 120 and 140 beats/min and six goats for the Study for native heart rhythm. We tested three modes: the circuit clamp, the continuous mode and the pulsatile mode. In the pulsatile mode, rotational speed was increased during the initial 35 % of the RR interval by automatic control based on the electrocardiogram. Pulsatility was evaluated by pulse pressure and dP/dt max of aortic pressure. As a result, comparing the pulsatile mode with the continuous mode, the pulse pressure was 28.5 ± 5.7 vs. 20.3 ± 7.9 mmHg, mean dP/dt max was 775.0 ± 230.5 vs 442.4 ± 184.7 mmHg/s at 80 bpm in the study for fixed heart rate, respectively (P < 0.05). The system successfully determined the heart rate to be 94.6 % in native heart rhythm. Furthermore, pulse pressure was 41.5 ± 7.9 vs. 27.8 ± 5.6 mmHg, mean dP/dt max was 716.2 ± 133.9 vs 405.2 ± 86.0 mmHg/s, respectively (P < 0.01). In conclusion, our newly developed the pulsatile mode for continuous-flow LVADs reliably provided physiological pulsatility with following heart rate variability.

In vitro comparison of the hemocompatibility of two centrifugal left ventricular assist devices.

OBJECTIVES: Shear stress from left ventricular assist devices induces von Willebrand factor degradation and platelet dysfunction, leading to nonsurgical bleeding. We characterized the hemostatic changes induced by 2 centrifugal left ventricular assist devices, the HeartMate 3 (Abbott Inc, Chicago, Ill) and the EVAHEART (Evaheart Inc, Houston, Tex), for comparison. METHODS: Whole blood from 8 healthy volunteers was used ex vivo. Blood from the same donor was used for 6 hours of circulation in a miniature mock-loop system consisting of 2 identical extracorporeal circuits to compare the following experimental settings: (1) optimal revolutions per minute (rpm) for the HeartMate 3 (n = 4; 5000 rpm) and the EVAHEART (n = 4; 2500 rpm) and (2) equal rpm (3000 rpm for the HeartMate 3 and EVAHEART, n = 4 vs n = 4). For both settings, blood flow was adjusted to 1 mock-loop filling volume per minute (HeartMate 3 = 82 mL/min, EVAHEART = 100 mL/min). A panel of coagulation markers was analyzed to investigate hemostatic changes. RESULTS: The free plasma hemoglobin concentration was significantly lower in the EVAHEART compared with the HeartMate 3 after 6 hours of mock-loop circulation under both settings (optimal: 37 ± 31 vs 503 ± 173 mg/dL, P < .0001; equal: 27 ± 4 vs 139 ± 135 mg/dL, P = .024). Loss of von Willebrand factor high-molecular-weight multimers occurred in both left ventricular assist devices and settings, but the von Willebrand factor:activity/von Willebrand factor:antigen ratio after 6 hours was significantly lower in optimal settings for the HeartMate 3 (P = .009). The thrombin-antithrombin complex level was significantly lower with the EVAHEART for both settings (P < .0001). CONCLUSIONS: The EVAHEART left ventricular assist device caused less hemolysis, resulted in lower coagulation activation, and provided better preservation of von Willebrand factor functional activity compared with the HeartMate 3 device. These findings prove that left ventricular assist device design plays a major role in minimizing blood damage during left ventricular assist device support.

Post-approval study of a highly pulsed, low-shear-rate, continuous-flow, left ventricular assist device, EVAHEART: a Japanese multicenter study using J-MACS.

BACKGROUND: The EVAHEART left ventricular assist device was approved in 2010 by the Japanese Pharmaceuticals and Medical Devices Agency (PMDA) for bridge to heart transplantation (BTT). However, its effectiveness has not been evaluated since approval. In this study we evaluated the EVAHEART device in a commercial setting in Japan. METHODS: Ninety-six consecutive patients enrolled in the Japanese Registry for Mechanically Assisted Circulatory Support (J-MACS), who were listed for transplant or likely to be listed and who received an EVAHEART device, were enrolled from 2011 to 2013 at 14 Japanese centers. Patients' survival rates, adverse events and quality-of-life data were obtained from the J-MACS Registry. RESULTS: Patients' median age was 43 years (85% male). The Interagency Registry for Mechanically Assisted Circulatory Support profiles revealed 12 patients in Level 1, 45 in Level 2, 37 in Level 3 and 1 in Level 4. The mean support duration was 384.7 days, with a cumulative duration of 101.2 years. The Kaplan-Meier survival rate during support was 93.4% at 6 months, 87.4% at 1 year and 87.4% at 2 years. Seventy-seven patients (80.2%) currently remain on support, 7 received a transplant and 10 died during support. Major adverse events included drive-line infection (14.6%) and neurologic events such as ischemic stroke (17.7%), hemorrhage (13.5%), transient ischemic attack (3.1%), pump thrombosis (1%) and hemolysis (1%). There was no gastrointestinal (GI) bleeding or right heart failure requiring right ventricular assist device (RVAD). There was no pump exchange due to mechanical failure. CONCLUSIONS: The EVAHEART device provides safe, reliable and long-term circulatory support with improved survival in commercial settings of BTT in Japan, where the transplant waiting period is much longer. Incidences of GI bleeding, hemolysis, right ventricular failure, device thrombosis and mechanical failure were extremely rare in patients on EVAHEART devices.