Ventricular Assist Device (VAD)

Indications for Ventricular Assist Devices (VAD) (Modified from Circulation, 2009) [MEDLINE]

Clinical Scenarios in Which Ventricular Assist Devices (VAD) May Be Used

Bridge to Transplantation

  • Use of an Intermediate/Long-Term Left Ventricular Assist Device in Patient Who is or May Be a Heart Transplant Candidate, But is Too Unstable to Wait Any Longer without Circulatory Support
    • Used in Worsening NYHA Class IIIB-IV Patients Despite Inotropic Therapy and Intra-Aortic Balloon Pump Support
    • Patients May Have Organ Dysfunction or Potentially Reversible Medical Conditions Which are Temporary Contraindications to Heart Transplant
    • LVAD Used in this Setting May Allow for Improved Secondary Organ Function, Improved Nutrition, and Decreased Pulmonary Hypertension: all of which may improve post-heart transplant survival
  • Epidemiology
    • Due to a Static Number of Donor Hearts, an Increasing Number of Patients Have Required LVAD Prior to Heart Transplant
      • LVAD Therapy Has Increased from 13.4% to 20.1% Over the Last Two Decades (1992-2001 to 2002-2009)
  • Indications
    • Patient is a Heart Transplant Candidate

Bridge to Decision (Regarding Heart Transplant Eligibility)

  • Use of an Intermediate/Long-Term Left Ventricular Assist Device Before a Final Heart Transplant Decision Has Been Reached
    • Approximately 30% of LVAD’s Inserted Between 2006-2013 Were Done So as a Bridge to Decision
    • Use of LVAD in this Setting May Complicate Planning: discouraged by some third-party insurers/payers

Bridge to Recovery

  • Use of an Intermediate/Long-Term Left Ventricular Assist Device While Waiting for Recovery
    • There is Evidence that LVAD Unloading Can Promote Recovery of Myocardial Function (Particularly in Acute Myocarditis): this allows LVAD to be removed from some patients without heart transplant
    • Pharmacologic Agents (ACE Inhbitors, Beta Blockers, Aldosterone Antagonists) May Be Used at Higher Doses While on LVAD Than Would Have Been Tolerated Prior to the LVAD: these agents may function to reverse athologic hypertrophy and remodeling, normalize myocardial metabolic function
      • Clenbuterol (an Anabolic Steroid) Has Been Used in This Setting: induces physiologic hypertrophy in experimental models (including models with pressure overload hypertrophy)
  • Clinical Efficacy
    • Utah Cardiac Recovery Program (UCAR) Study of Continuous Flow LVAD Unloading (J Am Coll Cardiol, 2013) [MEDLINE]
      • After 6 Months, 34% of Patients Had a Relative LV Ejection Fraction Increase Above 50% and 19% Achieved an Ejection Fraction Increase ≥40%
      • LV Systolic Function Improved as Early as 30 Days with the Greatest Degree of Improvement by 6 mo (Which Persisted at 1 Year Follow-Up)
      • LV Diastolic Parameters Also Improved as Early as 30 Days and Persisted Over Time
      • LV Mass Decreased as Early as 30 Days and Continued to Do So Over the the 1 Year Follow-Up, But Did Not Reach Values Below the Normal Reference Range: this suggests that there is no atrophic remodeling after prolonged LVAD unloading

Destination Therapy

  • Use of an Intermediate/Long-Term Left Ventricular Assist Device as a Final Treatment Has Increased with Improved Long-Term Survival Rates of These Devices
    • There are Currently 141 Medical Centers in the US Which are Medicare-Designated Destination Centers
    • Percentage of Destination Implants Has Increased Significantly from 14.7% to 41.6% from 2006-2007 to 2011-2013: this correlates with a decrease in percentage implanted as bridge to transplantation (from 42.4% to 21.7%)
  • Risk Factors for Early Death in These Cases
    • Age
    • Critical Cardiogenic Shock (see Cardiogenic Shock, [[Cardiogenic Shock]])
    • Diabetes Mellitus (see Diabetes Mellitus, [[Diabetes Mellitus]])
    • Pulmonary Hypertension (see Pulmonary Hypertension, [[Pulmonary Hypertension]])
    • Hyponatremia (see Hyponatremia, [[Hyponatremia]])
    • Elevated Blood Urea Nitrogen (BUN)
    • Need for Concomitant Surgery
    • Need for Biventricular Assist Device (Bi-VAD) Support
  • Indications
    • Continued Need for Intravenous Inotropic Therapy Limited by Symptomatic Hypotension, Decreasing Renal Function, or Worsening Pulmonary Congestion: Medicare specifies this criterion as a requirement for VAD destination therapy
    • Failure to Respond to Optimal Medical Management for >60 of the Last 90 Days: Medicare specifies this criterion as a requirement for VAD destination therapy
    • LV Ejection Fraction ≤25%: Medicare specifies this criterion as a requirement for VAD destination therapy
    • Patient is Not a Candidate for Heart Transplant (see Cardiac Transplant, [[Cardiac Transplant]]): Medicare specifies this criterion as a requirement for VAD destination therapy
  • Clinical Efficacy
    • REMATCH Trial (NEJM, 2001) [MEDLINE]: landmark trial
      • Left Ventricular Assist Device (Heartmate I) in Patients with Advanced Heart Failure Improved Survival (48% Decrease in All-Cause Mortality) and Improved Quality of Life

Relative Contraindications to Ventricular Assist Device (VAD) (Modified from Circulation, 2009) [MEDLINE]

Contraindications to Ventricular Assist Device (VAD) (Modified from Circulation, 2009) [MEDLINE]


Device Structure, Design, and Effects on Physiology

Components of Left Ventricular Assist Devices (LVAD) System

  • Cannula Placed into the Apex of the Heart
  • Pump
  • Outflow Conduit Sutured to the Aorta
  • Driveline Tunneled Out of Body to a Belt Controller and Batteries

Hemodynamic Consequences of Left Ventricular Assist Devices (LVAD) Implantation

  • Decreased Pulmonary Hypertension (Decreased RV Afterload)
    • Decrease in the Pulmonary Artery Pressure May Not Occur Immediately After Implantation, But May Take Weeks-Months
    • In Some Cases, Pulmonary Artery Pressure May Instead Increase After Implantation
  • Improved RV Compliance
  • Increased Venous Return to Right Side of the Heart: due to the increase in forward flow
    • This Effect May Contribute to the Development of Post-LVAD Implantation RV Dysfunction
  • Leftward Shift of Intraventricular Septum

Continuous Flow vs Pulsatile Flow Pumps

  • Continuous Flow Pumps Have Demonstrated a Clear Survival Advantage Over Pulsatile Pumps
  • Continuous Flow Ventricular Output Has Defined Adverse Physiologic Effects
    • Endothelial Dysfunction
    • Glomerular Periarteritis
    • Impaired Gas Exchange: observed in animal models
    • Impaired Nitric Oxide Production
    • Increased Inflammatory Biomakers (TNFα, CRP)
    • Organ Microcirculatory Dysfunction

Types of Ventricular Assist Devices (VAD’s)

Differences Between Left Ventricular Assist Device (LVAD) vs Biventricular Assist Device (BIVAD)

  • Clinical Efficacy
    • Patients Receiving BiVAD Support are More Critically Ill at the Time of Mechanical Cardiac Support Implantation (J Heart Lung Transplant, 2011) [MEDLINE]
    • Biventricular Assist Device Recipients Have Lower Survival Rates and Higher Serious Adverse Event Rates than Patients Requiring LVAD Support (J Heart Lung Transplant, 2011) [MEDLINE]

Third-Generation Left Ventricular Assist Devices (LVAD)

  • HeartWare
    • Device Features: continuous flow centrifugal pump
      • Device Has Impeller and No Mechanical Bearings: should have long durability
    • FDA Approval: approved in 2012 as bridge to transplantation
  • Heartmate II/III (Thoratec Corp)
    • Device Features: fully levitated centrifugal flow device inserted in the apex of the LV
      • May Decrease Sheer Stress and Lower Device Complications
    • Current Trials: non-inferiority trial comparing Heartmate II to Heartmate III
  • DuraHeart (XXX)

Biventricular Assist Devices (BVAD)

  • SynCardia Total Artificial Heart (TAH) Device
    • Originally Developed 30 years Ago as the Jarvik Total Artificial Heart and Late Renamed the CardioWest TAH
    • Over 1100 Patients Have Been Implanted: longest implantation prior to heart transplant is 1374 days
    • Device Features
      • Pulsatile Total Artificial Heart
  • Thoratec PVAD Used as a Biventricular Device
    • This Device Has Only Intermediate Durability

Effects of Respiratory Physiology/Mechanical Ventilation

  • Pulmonary Vasoconstriction May Increase Pulmonary Vascular Resistance, Worsening RV Dysfunction
  • By Computer Models, Increasing Positive Intrathoracic Pressure Increases RV Efficiency and Decreases LV Efficiency
    • This Effect Offsets the Increase in RV Stroke Work Created by the Continuous Flow Pump
    • Consequently, RV Function May Worsen After Extubation


Anticoagulation/Anti-Platelet Agents

Ventricular Assist Device (VAD) Parameters

Device Parameters to Set

Device Parameters to Monitor

Other Problems

Physical Exam Findings

Blood Pressure Management

General Comments

Blood Pressure Measurement

Pulse Oximetry (see Pulse Oximetry, [[Pulse Oximetry]])

Echocargiogram (see Echocargiogram, [[Echocargiogram]])

Adverse Effects/Complications

General Comments

Cardiovascular Adverse Effects/Complications

Left Ventricular Thrombus/Thromboembolic Complications

Right Ventricular Dysfunction After Left Ventricular Assist Device (LVAD) Implantation

Ventricular Arrhythmias

Gastrointestinal Adverse Effects/Complications

Gastrointestinal Hemorrhage (see Gastrointestinal Hemorrhage, [[Gastrointestinal Hemorrhage]])

Hematologic Adverse Effects/Complications

Hemolysis (see Hemolytic Anemia, [[Hemolytic Anemia]])


Thrombocytopenia (see Thrombocytopenia, [[Thrombocytopenia]])

Infectious Adverse Effects/Complications

Infection (see Sepsis, [[Sepsis]])

Neurologic Adverse Effects/Complications

Intracranial Hemorrhage


Risk Factors for Mortality After Ventricular Assist Devices (VAD) Implantation (Modified from Circulation, 2009) [MEDLINE]

Destination Therapy Risk Score

Risk Factors for Mortality After Left Ventricular Assist Devices (LVAD) Implantation (J Heart Lung Transplant, 2014) [MEDLINE]