Description

• Left ventricular assist devices (LVAD) are portable mechanical circulatory support devices that assist in pumping blood from the left ventricle to the aorta in patients with severe heart failure (HF)
• Goals of VAD therapy:
  • Bridge to transplantation (BTT): 8.9%, support cardiac function prior to heart transplant
  • Bridge to recovery (BTR): 18%, support cardiac function for a temporary recovery period (reversible pathology)
  • Destination therapy (DT): 73.1%, Support cardiac function, improvement in quality of life
• Components:
  • Inflow cannula (from left ventricle into the pump)
  • Pump: Continuous blood flow
    • Patient has no palpable pulse due to LVAD continuous flow
  • Outflow cannula (to the ascending aorta)
  • Percutaneous driveline: Connects pump to external system controller
  • System controller:
    • Regulates motor power and speed
    • Alarm display
    • Performs diagnostic monitoring
    • Stores data for download
  • Batteries (typically 2): Powers system controller and pump
  • Power base unit: Charges batteries, powers controller and pump

Epidemiology

• 56.2 million patients with HF worldwide
• 6.7 million patients with HF in the US
• Up to 150,000 patients classified with severe HF, with heart transplant being treatment of choice when medical management has failed
• 2.7-mo transplant wait time (2019–2020)
• Annual mortality rate for patient awaiting heart transplant has dropped continuously from 17% in 2001 due to LVAD as BTT
• VAD present in 34.5% of patients at the time of transplantation
• Nearly 50% of patients with newly implanted LVADs visit the ED within the 1st month of implantation, with an average of 7 ED visits in the 1st year

Etiology

Common LVAD-associated emergencies

• Bleeding – most common major complication:
  • Intracranial hemorrhage (ICH)
  • Gastrointestinal (∼30% of LVAD patients):
    • Arteriovenous malformations (AVMs)
    • Angiodysplasias
  • Hematuria
  • Epistaxis
• Anemia (0.5–18% of patients):
  • Patients are anticoagulated
  • Acquired von Willebrand disease type 2A due to shear stress on red blood cells
  • Reduced pulse pressure leads to AVMs
• Infection (30–50% of patients):
  • Driveline: Most common (17–30%)
  • Pump pocket (2–10%)
  • Cannula or device (0.6%)
  • Bloodstream (20–27%)
• Suction events: Excessive negative pressure causing partial ventricular collapse
• Poor perfusion:
  • Thrombosis (35%) can lead to pump/device failure
  • Mechanical pump failure
  • Pump speed too high
  • Non-LVAD related causes
• Arrhythmias:
  • AFib, flutter, and SVTs reduce LVAD preload; managed with rate control, anticoagulation, or cardioversion
  • Atrial fibrillation is the most common atrial arrhythmia
  • Ventricular arrhythmias may be tolerated but require amiodarone, cardioversion, or defibrillation if unstable
• Cardiac arrest