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Noninvasive measurements of blood pressure (BP) and cardiac output (CO) are crucial in the follow-up of continuous-flow left ventricular assist device (CF-LVAD) patients. For our pilot study, we sought to compare BP measurements between a tonometry blood pressure pulse analyzer (BPPA) (DMP-Life, DAEYOMEDI Co., Ltd., Gyeonggi-do, South Korea) and Doppler ultrasound in CF-LVAD patients, as well as to compare the BPPA estimated CO to LVAD calculated blood flow and to the patient's intrinsic CO estimated with transthoracic echocardiography (TTE). Ambulatory CF-LVAD patients (6 HeartMate, 26 HeartMate II), were included. According to TTE findings, patients were then subdivided in two groups: patients with an opening aortic valve (OAV) [n = 21] and those with an intermittent opening aortic valve (IOAV) [n = 11]. We found a very good correlation of systolic BP (SBP) measurements between the two methods, BPPA and Doppler ultrasound (r = 0.87, P < 0.0001). Bland-Altman plots for SBP revealed a low bias of -4.6 mm Hg and SD of ±4.7 mm Hg. In CF-LVAD patients with IOAV, the BPPA-CO had a good correlation with the LVAD-flow (r = 0.78, P < 0.0001), but in OAV patients, there was no correlation. After adding the patient's intrinsic CO, estimated from TTE in patients with OAV to the LVAD-flow, we found a very good correlation between the BPPA-CO and LVAD-flow + TTE-CO (r = 0.81, P = 0.002). Our study demonstrated that compared with the standard clinical method, Doppler ultrasound, the BPPA measured BP noninvasively with good accuracy and precision of agreement. In addition, tonometry BPPA provided further valuable information regarding the CF-LVAD patient's intrinsic CO., (© 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.)

A mock heart circulation loop (MHCL) is a hydraulic model simulating the human circulatory system. It allows in vitro investigations of the interaction between cardiac assist devices and the human circulatory system. In this study, a preload sensitive MHCL, the MHCL AUTO , was developed to investigate the interaction between the left ventricle and left ventricular assist devices (LVADs). The Frank-Starling mechanism was modeled by regulating the stroke volume (SV) based on the measured mean diastolic left atrial pressure (MLAP diast ). The baroreflex autoregulation mechanism was implemented to maintain a constant mean aortic pressure (MAP) by varying ventricular contractility (E max ), heart rate (HR), afterload/systemic vascular resistance (SVR) and unstressed venous volume (UVV). The DP3 blood pump (Medos Medizintechnik GmbH) was used to simulate the LVAD. Characteristic parameters were measured in pathological conditions both with and without LVAD to assess the hemodynamic effect of LVAD on the MHCL AUTO . The results obtained from the MHCL AUTO show a high correlation to literature data. The study demonstrates the possibility of using the MHCL AUTO as a research tool to better understand the physiological interactions between cardiac implants and human circulation., (Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.)