II. Indications: Congestive Heart Failure

  1. Criteria
    1. NYHA Class 4 Heart Failure
    2. Ejection Fraction <25%
    3. VO2 Max <15
    4. Poor response to optimal medical management (e.g. Beta Blockers, ACE Inhibitors)
    5. Life Expectancy <2 years
  2. Scenarios (three possible)
    1. Bridge to Heart Transplant
    2. Destination therapy
      1. Primary treatment for those not candidates for Heart Transplant
    3. Reversible disease (e.g. severe Myocarditis)
      1. Bridge to recovery (remodeling of heart allows for LVAD removal)

III. Mechanism

  1. Blood is shunted from ventricle to external pump and back to outflow tract
    1. Pump blood flow capacity up to 10 L/min
  2. Left Ventricular Assist Device (LVAD)
    1. Shunts blood from inflow cannula at the left ventricle apex via external pump
    2. Transfers blood to outflow cannula in the proximal aorta
  3. Biventricular Assist Device (BiVAD)
    1. Shunts blood from both ventricles via external pump
  4. Power
    1. Driveline exits implanted device and is tunneled via skin
    2. Driveline connects to controller
    3. Controller connects to AC power base unit or to two batteries
      1. Allows for battery to be changed without device interruption
      2. One battery or AC power base unit must be connected at all times

IV. Precautions

  1. Patients are instructed to carry emergency supplies with them
    1. Backup controller
    2. Charged spare batteries
    3. Cords to connect the battery packs to a charger
    4. Emergency card with device information and their VAD treatment team (e.g. VAD coordinator, cardiologist, CV surgeon)

V. Preparations: LVAD

  1. First Generation LVAD
    1. Pulsatile-flow mechanism
    2. Bulky and less durable
  2. Second Generation LVAD
    1. Continuous-flow mechanism (via centrifugal or axial flow pump)
    2. Smaller, more durable and quieter than first generation pumps
    3. Pump implanted in Abdomen (HeartMate II) or chest (HeartWare)

VI. Symptoms

  1. Maintain a high level of suspicion for serious underlying cause in LVAD patients
  2. Patients with LVAD malfunction may present nonspecifically despite potentially lethal impending decompensation
    1. Weakness
    2. Malaise

VII. Exam: Continuous Flow LVAD

  1. Auscultation
    1. A working continuous flow LVAD should emit a continuous hum
  2. Arterial Pulses are weak or absent and Pulse Pressure is decreased
    1. If pulses present, standard Blood Pressure may be obtained
    2. Pulses are often absent with normally functioning continuous flow LVADs
  3. Mean arterial pressure (MAP) approximation (in place of standard BP)
    1. Apply manual cuff to arm and apply handheld doppler over brachial artery
    2. Slowly lower cuff pressure
    3. Listen for start of Karotkoff sound (will not be pulsatile with continuous flow LVAD)
    4. Onset of Karotkoff sound approximates MAP
    5. Goal MAP: 70-90 mmHg
      1. Hypertension (increased Afterload) puts the LVAD patient at risk for pump malfunction and failure
  4. Oxygen Saturation
    1. Typically unreliable with continuous flow LVAD and decreased Pulse Pressure
    2. Consider cerebral oximetry instead

VIII. Labs

  1. Basic metabolic panel (Chem8)
    1. Electrolytes
    2. Renal Function tests (BUN and Serum Creatinine)
  2. Complete Blood Count
    1. Evaluate for Anemia and Thrombocytopenia
  3. INR
    1. Typical goal for LVAD: 1.5 to 2.5 (ideally 1.8 to 2.3)
  4. Other labs as indicated
    1. Serum Troponin
    2. Infection suspected
      1. Serum Lactate
      2. Blood Cultures
    3. Significant Hemolysis suspected
      1. Lactate Dehydrogenase (LDH) increased

IX. Diagnostics: As Indicated

X. Imaging: As Indicated

  1. Chest XRay
  2. Echocardiogram (or Bedside Ultrasound)
    1. See Inferior Vena Cava Ultrasound for Volume Status
    2. See Inflow cannula obstruction or malposition (below)

XI. Management: Approach Emergency Department

  1. Contact VAD team on patient arrival (LVAD coordinator or cardiothoracic surgeon)
  2. Evaluate device power (interruption of power even briefly is an emergency)
    1. Check driveline skin exit (for Trauma) and its connection to controller
    2. Check controller connection to batteries
    3. Check for green light on controller (indicates device is powered)
    4. Plug driveline into AC power base unit if available (to conserve battery power)
    5. Feel the controller for excessive heat
      1. Suggests increased circuit resistance
      2. May indicate device malfunction, pump thrombosis or increased Afterload
  3. Evaluate that device is functioning
    1. Check for warning lights or alarms on device
    2. Auscultate for the hum or blender-like sound of an operating LVAD
  4. Evaluate for signs infection
    1. Evaluate skin overlying driveline (or sternal incision if recent implantation)
    2. Consider evaluating pump pocket or device endocarditis with Echocardiogram
    3. Consider other infection sites (e.g. Urinary Tract Infection, Pneumonia) with risk of seeding the device
  5. Evaluate for signs of Fluid Overload (e.g. rales, edema, JVD)
  6. Evaluate for Hypertension (MAP >90 mmHg)
    1. MAP over 90 mmHg is a risk of CVA and impaired Cardiac Function
    2. Consider Fluid Overload or missed antihypertensive dose
    3. Consider Beta Blocker or ACE Inhibitor (consult cardiology)
  7. Evaluate for Hypotension (MAP <60 mmHg)
    1. Consider causes (see each described in detail below under complications)
      1. Obtain Echocardiogram and coagulation panel
    2. Dehydration
    3. Gastrointestinal Bleeding
    4. Infection (Sepsis)
    5. Right ventricular dysfunction with Heart Failure exacerbation
    6. Inflow cannula obstruction or malposition
    7. Pump thrombosis (increased risk when MAP <60)
  8. Evaluate for arrhythmia
    1. See Tachyarrhythmia below (VF, VT, a fib with RVR, SVT)
    2. See Cardiac Arrest below

XII. Complications: Infection

  1. Infection occurs in 18-36% of LVAD implantations
    1. Infection is less common with continuous-flow devices by more than 2.5 fold
    2. May present non-specifically (e.g. weight loss, Fatigue, low-grade fever)
    3. Primary cause of death for LVAD patients
      1. First month: 8.6% of deaths
      2. After the first month: 20.5% of deaths
  2. Sites
    1. Non-LVAD related infections (UTI, Pneumonia, Cellulitis)
    2. Sternal incision infection (mediastinitis)
    3. LVAD pump pocket or pump infection
      1. Presents with vague symptoms (weight loss, malaise and low grade fever)
      2. Consider Echocardiogram or CT to evaluate device or pocket for infection
      3. Pump pocket infection
        1. Introduced in perioperative period (near the time of pump insertion)
      4. LVAD Endocarditis
        1. Pump may be seeded with Bacteria or fungus resulting
    4. Driveline infection
      1. Most common site of infection
      2. Often responds to antibiotics alone (without surgical drainage), covering for organisms listed below
      3. May result if driveline wire fails to adhere well to surrounding tissue (excessive manipulation)
        1. Allows for pocket to form along the driveline, in which infection can develop
      4. Presents with driveline exit site signs of infection
        1. Purulent drainage
        2. Erythema or tenderness or persistent serous drainage
        3. Wound dehiscence
      5. Prevention
        1. Avoid excessive manipulation of the driveline after insertion
        2. Daily cleaning of the driveline skin exit site
  3. Organisms (high risk of nosocomial organisms and Gram Negative infections)
    1. Staphylococcus aureus (including MRSA)
    2. Staphylococcus epidermidis
    3. Enterococcus
    4. Pseudomonas aeruginosa
    5. Klebsiella
    6. Enterobacter
    7. Fungal organisms
  4. Evaluation and Management
    1. Consider CT chest and CT Abdomen if mediastinitis, LVAD pump or pump pocket infection is suspected
    2. Consultation with cardiothoracic surgery
    3. Aim for MAP >65 mmHg in Sepsis via IV fluids
    4. Vasopressors may be needed
    5. Cover for Bacteria listed below with broad spectrum antibiotics
      1. Vancomycin (preferred) or Daptomycin AND
      2. Cefepime (preferred) or Ciprofloxacin or Levofloxacin AND
      3. Fluconazole (preferred) or Voriconazole, Caspofungin, Micafungin, Anidulafungin
  5. References
    1. (2016) Sanford Guide, accessed 4/8/2016
    2. Gordon (2006) Lancet Infect Dis 6(7): 426-37 [PubMed]
    3. Pereda (2011) Cardiol Clin 29(4): 515-27 [PubMed]
    4. Topkara (2010) Ann Thorac Surg 90(4): 1270-7 [PubMed]

XIII. Complications: Bleeding

  1. Anticoagulation
    1. Most patients with LVAD or BiVAD are dual anticoagulated (e.g. Coumadin and Aspirin)
    2. Coumadin may be transiently stopped for major bleeding without serious risk of Thromboembolism in the short-term
      1. Reverse Coagulopathy in serious bleeding events (e.g. Vitamin K, Platelet Transfusion, DDAVP)
  2. Small Bowel angiodysplasia (Intestinal arteriovenous malformation)
    1. Unclear etiology, although postulated to result from decreased intestinal mucosal perfusion
    2. Most common cause of Gastrointestinal Bleeding in LVAD patients
  3. Mechanical lysis of blood factors
    1. Acquired Von Willebrand's Disease (mechanical lysis of vwF)
    2. LVAD pump related Hemolysis (mechanical lysis of Red Blood Cells)
  4. Presentations
    1. Gastrointestinal Bleeding is the most common presentation

XIV. Complications: Pump failure

  1. Presents with a pulseless patient in extremis
  2. Pump failure results in blood backflow into ventricle, and resistance to forward flow
    1. LVAD dependent patients (e.g. severe Aortic Stenosis) will have no forward systemic flow
  3. Auscultate chest (or Abdomen) to confirm that the pump is working (hum or blender-like sound)
  4. Check tubes, cables and controller
  5. Assess if the LVAD controller is over-heating (see above)
  6. Check battery power remaining (press button on battery)
    1. Patient should have extra batteries with the pump
    2. Patient may have power pack that allows for AC plug-in
    3. EMS may also have available AC base power supplies
  7. Evaluate pump output
    1. Obtain mean arterial pressure via doppler Ultrasound
    2. Obtain EKG to assess for acute Myocardial Infarction or arrhythmia
    3. Obtain Echocardiogram to assess for interval changes from prior Echocardiogram
  8. Assess alarms
    1. Red lights or audible alarms suggest impending pump failure (address emergently)
  9. Restarting a stopped pump
    1. Press "Test Select" or "Alarm Reset" buttons may restart the LVAD

XV. Complications: Inflow cannula obstruction or malposition

  1. Evaluate with Bedside Ultrasound
    1. Evaluate left ventricular and right ventricular function
    2. Small right ventricle and left ventricular collapse may suggest hypovolemia (see below)
  2. Hypovelemia allows left ventricle to collapse over the LVAD inflow cannula (suction event, suck-down phenomenon)
    1. Results in obstructing blood flow into the device
    2. Fluid bolus may re-expand left ventricle and relieve obstruction
  3. Inflow cannula may also be malpositioned
    1. Urgent cardiovascular surgeon Consultation

XVI. Complications: Pump thrombosis

  1. Pump may become clogged with clot
  2. Emergent condition typically presenting with MAP <60 mmHg
  3. Evaluate pump parameters
    1. Pump parameters are available when the pump is on external power
    2. High pump power despite slowed pump speed and decreased flow may suggest pump thrombosis
  4. Labs
    1. Lactate Dehydrogenase (LDH) may be increased, and hemoglobuniuria may occur
  5. Management
    1. Consider intravenous Thrombolytics

XVII. Complications: Heart Failure exacerbation despite pump operating

  1. Right ventricular dysfunction is common after LVAD insertion
  2. Consider Endotracheal Intubation
    1. May decrease Pulmonary Hypertension
    2. May improve Respiratory Acidosis and Metabolic Acidosis
  3. Consider pressors

XVIII. Complications: Tachyarrhythmia

  1. Common arrhythmias
    1. Ventricular Tachycardia or Ventricular Fibrillation
      1. Sustained VT or VF occurs in up to 52% of LVAD patients
      2. May be asymptomatic for days in some LVAD patients
      3. Those with AICD may fire repeatedly
    2. Atrial Fibrillation or Atrial Flutter
    3. Supraventricular Tachycardia
  2. Presentation
    1. Right-sided Heart Failure
      1. Decreased left Ventricular Preload may result in Syncope, light headedness or weakness
  3. Management
    1. AICD may fire repeatedly if present
    2. Consult with VAD team when able
    3. Cardioversion is critical
      1. Attempt chemical cardioversion (e.g. Procainamide, Amiodarone) in stable patients
      2. Electrical cardioversion if unstable or refractory tachyarrhythmia
        1. Avoid overlapping conductor pads over the LVAD (or AICD) if possible

XIX. Complications: Cardiac Arrest

  1. Precautions
    1. Absent pulse or Blood Pressure does not equate to Cardiac Arrest in the LVAD patient (see exam above)
    2. Chest Compressions may dislodge left ventricle LVAD inflow cannula
      1. Start Chest Compressions as a last resort, but do not withhold if indicated
      2. Abdominal only CPR has been suggested as possible option (experimental only)
    3. Avoid overlapping electrical Defibrillation conductor pads over the LVAD (or AICD) if possible
  2. Diagnostics
    1. Bedside Echocardiogram to evaluate assess left and right ventricles
    2. Confirm that LVAD is operational (see above under pump failure)
  3. Management
    1. Follow ACLS protocol (including electrical Defibrillation)
    2. Address pump failure, pump thrombosis, and inflow cannula obstruction (see above)
    3. Consider Intravenous FluidResuscitation if left ventricular collapse suspect (with inflow cannula obstruction)
  4. References
    1. Shinar (2014) Resuscitation 85(5): 702-4 [PubMed]

XX. Efficacy

  1. Survival rates (continuous flow devices)
    1. Year 1: 80% (compared with 25% on medical therapy)
    2. Year 2: 70% (compared with 8% on medical therapy)
    3. Kirklin (2013) J Heart Lung Transplant 32(2):141-56 [PubMed]

XXI. References

  1. Lo and Devine (2014) Crit Dec Emerg Med 28(7): 2-9
  2. Mallemat, Swaminathan and Egan in Herbert (2014) EM:Rap 14(10): 3-5
  3. Swadron and Shinar in Majoewsky (2012) EM:RAP 12(4): 4-5
  4. Vanlandingham (2015) Crit Dec Emerg Med 29(10): 2-14
  5. Klein (2012) Cardiol Clin 30(4): 673-82 [PubMed]

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