Abstract Objectives: A continuous-flow centrifugal blood pump system has been recently developed as an implantable left ventricular assist device for patients with end- stage heart failure. The objective of this study was to evaluate the initial in vivo performance of a newly developed left ventricular assist device (iHeart or Istanbul heart; Manufacturing and Automation Research Center, Koc University, Istanbul, Turkey) in an acute setting using a pig model. Materials and Methods: Three pigs (77, 83, 92 kg) received implants via a median sternotomy, with animals supported for up to 6 hours. An outflow cannula was anastomosed to the ascending aorta. Anticoagulation was applied by intravenous heparin administration. During the support period, pump performance was evaluated under several flow and operating conditions. All pigs were humanely sacrificied after the experiments, and organs were examined macroscopically and histopathologically. Results: Flow rate ranged between 1.5 and 3.6 L/min with pump speeds of 1500 to 2800 revolutions/min and motor current of 0.6 to 1.3 A. Initial findings confirmed that the iHeart ventricular assist device had sufficient hydraulic performance to support the circulation. During the experimental period, plasma free hemoglobin levels were found to be within normal ranges. Thrombus formation was not observed inside the pump in all experiments. Conclusions: The iHeart ventricular assist device demonstrated encouraging hemodynamic performance and good biocompatibility in the pig model for use as an implantable left ventricular assist device. Further acute in vivo studies will evaluate the short-term pump performance prior to chronic studies for long-term evaluation. Key words: Animal experiment, Centrifugal blood pump, Heart failure, Mechanical circulatory support Introduction Heart failure is a global life-threatening condition that affects more than 35 million people worldwide. 1,2 In Turkey, more than 2 million people have heart failure according to data from the Turkish Cardiology Association. 3 Although heart transplant is the best solution for treatment of end-stage heart failure, it is only available for a limited number of patients (< 100 patients) per year in Turkey. 3 Ventricular assist devices (VADs) have become an alternative therapy for patients with end-stage heart failure as a bridge to transplant, recovery, or destination treatment. 4-8 The demand for implantable VADs with a hydrodynamic impeller or magnetic suspension systems has been increasing worldwide because these devices show great potential for long-term survival and have extreme mechanical durability. 9-11 In 2001, Kucukaksu and associates performed the first application of an implantable left ventricular assist device (MicroMed DeBakey LVAD; MicroMed Technology, Houston, TX, USA) in Turkey. 12 However, the number of LVAD implantations remains restricted due to high operational costs. Cost-effective devices are thus needed to increase the clinical use of LVADs in Turkey. 13 Given these facts, a new centrifugal flow- type LVAD, named iHeart VAD (or Istanbul heart; Manufacturing and Automation Research Center, Copyright © Başkent University 2019 Printed in Turkey. All Rights Reserved. A Short-Term In Vivo Evaluation of the Istanbul Heart Left Ventricular Assist Device in a Pig Model Ismail Lazoglu, 1 Deniz Suha Kucukaksu, 2 Caglar Ozturk, 1 Ibrahim Basar Aka, 1 Vedat Bakuy, 2 Nurcan Arat, 3 Ozlem Yalcin, 4 Elif Ugurel, 4 Pelin Celikbilek Erkasap, 5 Emin Aksoy, 5 Sevket Ruacan 6 From the 1 Manufacturing and Automation Research Center, College of Engineering, Koc University, Istanbul, Turkey; the 2 Department of Cardiovascular Surgery, School of Medicine, Baskent University, Istanbul, Turkey; the 3 Department of Cardiology, School of Medicine, Istanbul Bilim University, Istanbul, Turkey; the 4 Department of Physiology, School of Medicine, Koc University, Istanbul, Turkey; the 5 Center of Advanced Simulation and Education, School of Medicine, Acıbadem University, Istanbul, Turkey; and the 6 Department of Pathology, School of Medicine, Koc University, Istanbul, Turkey Acknowledgements: The authors have no sources of funding for this study and have no conflicts of interest to declare. Corresponding author: Ismail Lazoglu, Koc University, Rumelifeneri Yolu, 34450, Sariyer, Istanbul, Turkey Phone: +90 212 3381587 E-mail: ilazoglu@ku.edu.tr Experimental and Clinical Transplantation (2019) ArtIcle DOI: 10.6002/ect.2019.0110