Sensitivity analysis of cardiac function detection for patients with ventricular assist device support

Maximum ventricular elastance, Emax, is a strong candidate representing the healthy status of a patient's heart. However evaluating Emax usually requires invasive pressure and flow sensors, which only can be performed under certain clinical facility. If an indirect index of Emax can be identified from the measurements of a ventricular assist device (VAD) without any indwelling sensor, this would facilitate an effective way to monitor the healthy condition of the patient's heart while the patients is under VAD support. This index can also be used to control the VAD to gradually wean the patient from the mechanical circulatory support. In this paper, two possible indices, pump flow pulsatility and arterial pulse pressure, were evaluated as a representation of Emax using data from a computer simulation model of cardiovascular system with a HeartMat II rotary type VAD. Pump flow pulsatility showed a strong correlation to Emax regardless of pump speed changes, and thus can be used as an Emax index.