Assessment of arterial blood pressure during support with an axial flow left ventricular assist device.

BACKGROUND: Axial-flow left ventricular assist devices (LVADs) have a number of advantages over pulsatile LVADs, including their small size and better durability. Although the design of axial-flow pumps should result in fewer serious complications during support, some adverse events persist. Thus, optimizing patient treatment may minimize complications, allowing broader acceptance of these devices. In this study, we analyzed standard blood pressure measurements obtained by cuff and arterial lines and used these values to help establish guidelines for the safe operation of axial-flow LVADs.
METHODS: The study included 35 heart failure patients who had received a Jarvik 2000 (Jarvik Heart Inc, New York, NY) axial-flow LVAD as a bridge to cardiac transplantation. Blood pressure and echocardiographic data were collected during speed-change studies.
RESULTS: Systolic blood pressure did not change, but diastolic, mean, and pulse pressure values changed significantly with changes in pump speed (p < 0.0001). When blood pressure values obtained from an arterial line were compared with those from an automated cuff machine, the systolic, diastolic, and mean values did not correlate (p < 0.05), but the calculated pulse pressures did (p = 0.33). A pulse pressure calculation of < 15 mm Hg resulted in aortic valve opening 24% of the time, and a pulse pressure > 15 mm Hg was predictive of aortic valve opening 65% of the time.
CONCLUSIONS: Because aortic valve opening minimizes the risk of complications, a safe zone for most patients is a pulse pressure > 15 mm Hg. Arterial blood pressure changes during axial-flow LVAD support can be predicted and may be used as a guide for the proper management of pump speed settings. A calculated pulse pressure from an arterial line or automated cuff may be used to determine a safe zone of Jarvik 2000 operation, leading to fewer complications.