Key result
Alteration in LVAD pump speed demonstrated a strong linear relationship with flow rates (r2 = 0.89, p < 0.00001), though marked interpatient variation and adverse events limited upward titration.
Why the study?
Does alteration in pump speed affect pump output and safety in stable outpatients with continuous-flow LVAD?
Does alteration in pump speed affect pump output and safety in stable outpatients with continuous-flow LVAD?
Effect estimate: r2 = 0.89
p-value: p=< 0.00001
LVAD pump flow is stable within a relatively small speed range and should not be altered without close monitoring due to the risk of ventricular suction or VT, particularly in patients with right ventricular impairment.
Interpatient variation and adverse events warrant caution with LVAD speed titration; leaves open safe outpatient protocols.
Third-generation continuous-flow left ventricular assist devices (LVAD) provide reduced pulsatility flow. We examined the safe working range for LVAD pump speed and the effect on pump output and cardiac function in 13 stable outpatients with VentrAssist-LVAD (Ventracor Ltd, Australia). Pump speed was decreased from a baseline mean of 2,073 ± 86 revolutions per minute (RPM, with corresponding mean flow of 5.59 ± 1.18 L/min, mean ± standard deviation) to an average low-speed of 1,835 ± 55 RPM (corresponding flow 4.68 ± 0.99 L/min) and up to high-speed of 2,315 ± 66 RPM (corresponding flow 6.30 ± 1.29 L/min). There was a strong linear relationship between alteration in speed and flow rates (r(2) = 0.89, p < 0.00001) but marked interpatient variation. Downward titration to preset minimum 1,800 RPM was achieved in 9/13 (69%) and upward titration to the preset maximum 2,400 RPM was achieved in 4/13 (31%). Upward titration was stopped due to ventricular suction or nonsustained ventricular tachycardia (VT) in 4/13 (31%). Ventricular suction or VT (in 4/13) tended to be more common in patients with poor right ventricular (RV) function (p = 0.07). In summary, pump flow is stable within a relatively small speed range and should not be altered without close monitoring due to variation in response between patients, particularly with concomitant RV impairment.
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Hayward et al. (2011) studied Stable outpatients with VentrAssist-LVAD (n=13). Alteration in LVAD pump speed vs. Baseline mean of 2,073 ± 86 RPM was evaluated on Relationship between alteration in speed and flow rates (r2 = 0.89, p=< 0.00001). Alteration in LVAD pump speed demonstrated a strong linear relationship with flow rates (r2 = 0.89, p < 0.00001), though marked interpatient variation and adverse events limited upward titration.
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