Miniaturized HIA Microdiagonal Pump as Left Ventricular Assist Device in a Sheep Model

Abstract

We evaluated the newly developed miniaturized HIA microdiagonal blood pump (MDP) as a continuous flow left ventricular assist device. In a sheep model (n = 6), the MDP was implanted through left lateral thoracotomy and placed paracorporeally with inflow conduit to left atrium and outflow conduit to descending aorta. The sheep were pumped at a mean flow rate of 2.5 L/min for 7 days. Anticoagulation was applied by intravenous heparin administration. Postoperatively, activated clotting time was held stable with values of 200 seconds. During follow-up, blood samples (creatinine kinase, creatinine, glutamic-oxaloacetic transaminase (aspartate aminotransferase) (GOT), glutamate dehydrogenase (GLDH), gamma-GT, plasma-free hemoglobin, and hemoglobine) were taken daily. After 7 days, the sheep were killed for macroscopic examination. Systemic artery pressures remained stable during the whole test period. Because of operative reasons, the hemoglobin value (7.5 +/- 0.61 g/dl) decreased perioperatively, but recovered within the test period, whereas creatinine kinase increased initially after thoracotomy, but decreased to normal within days. Renal and liver functions were slightly impaired perioperatively, indicated by temporarily enhanced values of GOT, gamma-GT, GLDH, and creatinine. The MDP did not produce significant hemolysis as measured by plasma-free hemoglobin levels. Wound infections did not occur. We conclude that the MDP ran successfully as an left ventricular assist device for 7 days in sheep has potential for long-term support, and may serve as an alternative to current technologies. Presented data were not obtained in a clinical trial; however, the results are promising enough to proceed with longer duration animal studies.

Influence of Mild Metabolic Acidosis on Cardiac Contractility and Isoprenaline Response in Isolated Ovine Myocardium

“…Underlining this, Kohlhardt et al described already in the 1960s a significant, moderateacidosisinduced cardiac output decrease in nonfailing cats by 25% (pH = 7.00) (13). Further investigations on acidosis-induced decrease of myocardial contractility and its effect on catecholamine response were performed using different approaches and models (14)(15)(16)(17)(18)(19)(20)(21)(22); however, there still exist no experimental data describing the specific effect of metabolic acidosis in isolated ovine hearts even though sheep are widely used as animal models (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41).…”

Two axial-flow Synergy Micro-Pumps as a biventricular assist device in an ovine animal model

“…18,22,29 However, patient mobility is limited, and risks of infection and other adverse events that compromise outcome are quite high. 10 For this reason, long-term options that allow for patient mobility with lower risks of adverse events are being sought.…”

“…28,29 The inflow cannula is designed for insertion into the atrium or, with an extended titanium cage into the ventricle. In either case, the tip can be used in the respective chambers on the right or left sides without modifications.…”

“…[23][24][25][26][27] However, these devices are not ideally suited for implantation in the right heart, and therefore, research on VADs remains necessary. [28][29][30][31][32][33][34][35][36][37][38][39][40] The Synergy Micro-Pump (CircuLite Inc, Saddle Brook, NJ) is the size of an AA battery, connects to the heart via an 8-mm-diameter by 20-cm-long inflow cannula, has a pumping capacity of up to ϳ4.25 liters/min, and is small enough to be placed in a subcutaneous pocket. [41][42][43] Although clinical experience is currently limited to pumping blood from the left atrium to the subclavian artery, recent cadaveric research has indicated that this micropump can also be easily positioned as an RVAD.…”

Minimally Invasive Ventricular Assist Device Surgery

“…Conventional LVAD procedures have been associated with major incisions, high complication rates, and poor outcomes, but the advent of minimally invasive techniques is changing the entire field . With the fast development and miniaturization of next‐generation devices, outcomes have improved significantly . Minimally invasive procedures mean smaller incisions, less blood loss, shorter hospital stays, and lower costs .…”