Comparison of Intraoperative Doppler Flow Measurement with Device-Provided Flow Estimation during Left Ventricular Assist Device Implantation

All articles of this category (opens in new window) Background: In fully magnetically levitated left ventricular assist devices (LVAD), blood flow is estimated by the device based on power consumption and blood viscosity. This study aimed to compare intraoperative Doppler flow measurements with device-provided flow values displayed on the device monitor. Methods: Twenty consecutive patients who underwent LVAD implantation with intraoperative Doppler-guided flow optimization between January and April 2025 were retrospectively analyzed. LVAD blood flow was routinely measured with a Doppler probe at the outflow graft after weaning from cardiopulmonary bypass. Measurements were obtained at multiple pump speeds: 4,400, 4,800, 5,200 rpm, and the final optimized speed. Concomitant transesophageal echocardiography was performed to guide optimal pump speed adjustment. Results: In this cohort of 20 patients, 15% were female, the median age was 63 years, and the mean BMI was 28.5 kg/m 2 . Preoperative comorbidities included diabetes (40%), COPD (15%), and CKD (25%). The etiology of heart failure was ischemic cardiomyopathy in 45% and nonischemic cardiomyopathy in 55%; 15% experienced prior cardiac arrest. Preoperative temporary mechanical circulatory support was present in 40%, with 30% bridged using a microaxial flow pump, 5% with ECLS, and 5% with combined ECLS and IABP. Across all speed settings, Doppler-derived flow exceeded device-displayed values by a consistent mean difference of 0.49 to 0.56 L/minutes (range: −0.1 to 1.0, p ≤ 0.001; [ Table 1 ]). Table 1 Pump speed (rpm) Flow probe (L/min) Flow pump (L/min) Mean difference (L/min) p -Value Power (W) Pulsatility index RVOT VTI (cm) 4,400 3.4 ± 0.4 2.9 ± 0.3 0.5695% CI (0.40, 0.70)