LVAD Pump Thrombosis — EECC MCQ
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Correct answer: C — Pump thrombosis — elevated power consumption reflects the motor working harder to overcome intraluminal thrombus obstruction; presents with haemolysis (elevated LDH, plasma-free haemoglobin), dark urine, and haemodynamic compromise
LVAD pump thrombosis is a serious complication (incidence 2-13% depending on device type). Clinical features: (1) elevated pump power (watts) — the motor increases speed to maintain flow against thrombotic resistance; (2) haemolysis — mechanical destruction of RBCs by thrombus: elevated LDH (>2.5x ULN), plasma-free haemoglobin, bilirubin, low haptoglobin, dark urine (haemoglobinuria); (3) haemodynamic compromise (HF symptoms, hypotension); (4) device alarms. Diagnosis: power spikes, haemolysis markers, echocardiographic assessment (ramp study — failure of LV to unload with speed increase). Management: (1) intensify anticoagulation (heparin bridge); (2) thrombolysis (tPA) for acute pump thrombosis — carries significant bleeding risk; (3) device exchange (surgical) if thrombolysis fails or is contraindicated. The HeartMate 3 (with artificial pulse) has significantly lower thrombosis rates than HeartMate II.
Reference: ESC (2023): HF Guidelines; MOMENTUM 3 Trial