Arterial Pulsatility in Patients with Continuous Flow Left Ventricular Assist Device Support: Comparing Velocity and Mean Arterial Pressure

Purpose An increasing number of end-stage heart failure patients are supported by continuous-flow Left Ventricular Assist Devices (cfLVADs) as a bridge to heart transplantation. Accurate assessment of arterial pulsatility remains a challenge because of diminished pulse pressure, which itself can be associated with adverse events such as gastrointestinal bleeding and stroke. Our study investigates the value of simultaneous arterial pressure and arterial blood velocity assessment in cfLVAD patients. Methods Brachial artery flow velocity (cm/s, Huntleigh) and brachial cuff oscillometry pressure (mmHg, Sphygmocor XCel) data were collected during outpatient visit. Velocity measurements obtained included peak, minimum, average velocity as well as pulsatility index. Pressure measurements obtained were systolic, diastolic as well as mean arterial pressure. Results Twelve velocity and pressure measurements were obtained from a total of nine VAD patients. Mean age was 57 years (Range 44-71). Mean device support duration was 187 days (Range 44-471). Mean brachial MAP was 92 mmHg (Range 74-112), whereas mean peak brachial artery velocity was 11 cm/s (Range 6-26). Mean pulsatility index was 3 (range 1-8). Correlation analysis using Spearman's rho demonstrated a significant inverse relationship between Brachial MAP and Peak velocity (Rho=-0.72, p=0.08). Conclusion Arterial flow measurements may provide incremental value over purely pressure-based assessment. Discrepancies between these modalities may provide further information regarding the arterial vasculature, specifically pertaining to the impact of higher MAP on blood flow.