TY - JOUR
T1 - Estimation of left ventricular pressure with the pump as "sensor" in patients with a continuous flow LVAD
AU - Pennings, Kim A. M. A.
AU - van Tuijl, Sjoerd
AU - van de Vosse, Frans N.
AU - de Mol, Bas A. J.
AU - Rutten, Marcel C. M.
PY - 2015/8
Y1 - 2015/8
N2 - In long-term ventricular support of patients with LVADs, left ventricular pressure (p(lv)) is relevant for indicating the unloading level of the heart. Monitoring of p(lv) over time might give more insight into the increase or decrease in native ventricular function. In this study, we aim to assess dynamic p(lv) noninvasively, using the LVAD as a pressure sensor.Pressure head (dp(lvad)) was estimated from pump flow with a dynamic pump model (1). Estimated dp(lvad) and measured aortic pressure were used to calculate left ventricular pressure. Moreover, parameters dp/dtmax and mean, minimum, and maximum p(lv) were derived.The method was validated with a porcine ex vivo beating heart model by measurements conducted in 4 hearts supported with a Micromed DeBakey VAD and 3 hearts with a Heartmate II VAD. During each measurement, aortic and left ventricular pressure, pump flow, and pressure head were recorded for 30 s with a sampling frequency of 1 kHz.The estimation of left ventricular pressure appeared to be accurate for both pumps. The parameters mean and minimum pressure were estimated with high accuracy. The degree of accuracy of the estimated p(lv) was proportional to the degree of accuracy of the dynamic pump model.We proved that the LVAD model described in this paper can be used as a pressure indicator to determine LV pressure at any time based on noninvasive measurements of pump flow, aortic pressure, and the properties of the outlet graft.
AB - In long-term ventricular support of patients with LVADs, left ventricular pressure (p(lv)) is relevant for indicating the unloading level of the heart. Monitoring of p(lv) over time might give more insight into the increase or decrease in native ventricular function. In this study, we aim to assess dynamic p(lv) noninvasively, using the LVAD as a pressure sensor.Pressure head (dp(lvad)) was estimated from pump flow with a dynamic pump model (1). Estimated dp(lvad) and measured aortic pressure were used to calculate left ventricular pressure. Moreover, parameters dp/dtmax and mean, minimum, and maximum p(lv) were derived.The method was validated with a porcine ex vivo beating heart model by measurements conducted in 4 hearts supported with a Micromed DeBakey VAD and 3 hearts with a Heartmate II VAD. During each measurement, aortic and left ventricular pressure, pump flow, and pressure head were recorded for 30 s with a sampling frequency of 1 kHz.The estimation of left ventricular pressure appeared to be accurate for both pumps. The parameters mean and minimum pressure were estimated with high accuracy. The degree of accuracy of the estimated p(lv) was proportional to the degree of accuracy of the dynamic pump model.We proved that the LVAD model described in this paper can be used as a pressure indicator to determine LV pressure at any time based on noninvasive measurements of pump flow, aortic pressure, and the properties of the outlet graft.
KW - LVAD
KW - Left ventricular assist device
KW - Left ventricular pressure
KW - Left ventricular function
KW - Pump characteristics
U2 - 10.5301/ijao.5000424
DO - 10.5301/ijao.5000424
M3 - Article
C2 - 26349533
SN - 0391-3988
VL - 38
SP - 433
EP - 443
JO - International Journal of Artificial Organs
JF - International Journal of Artificial Organs
IS - 8
ER -