Ventricular Assist Device (VAD)

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

  • Body Surface Area >1.5 m2
  • Continued Need for Intravenous Inotropic Therapy Limited by Symptomatic Hypotension, Worsening Renal Function, or Worsening Pulmonary Congestion
  • Failure to Respond to Optimal Medical Management for >60 of the Last 90 Days
  • Life Expectancy <2 yrs
  • Left Ventricular (LV) Ejection Fraction ≤25%
  • New York Heart Association (NYHA) Functional Class IV Symptoms
  • Progressive Cardiac Cachexia
  • Recurrent Symptomatic Sustained Ventricular Tachycardia or Ventricular Fibrillation in the Presence of an Untreatable Arrhythmogenic Substrate
  • Refractory Cardiogenic Shock or Cardiac Failure: without potential for recovery
    • Either Ischemic/Dilated Cardiomyopathy or Restrictive/Hypertrophic Cardiomyopathy
      • For Ischemic/Dilated Cardiomyopathy: ejection fraction <25% or cardiac index <2.2 L/min per m2
      • Data Suggest that the 1-Year Survival for LVAD Implantation in Ischemic/Dilated Cardiomyopathy vs Restrictive/Hypertrophic Cardiomyopathy are Comprarable
  • Threshold Levels: these are not required for bridge to transplantation, but are considered for later heart transplantation
    • Peak Oxygen Consumption ≤12 mL/kg/min with Cardiac Limitation
    • 6-Minute Walk Distance <300 m (see 6-Minute Walk Test, [[6-Minute Walk Test]])
  • Unmanageable Angina Unresponsive to Therapy or Revascularization

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]

  • Age >65 y/o: unless minimal or no other clinical risk factors
  • Chronic Kidney Disease (CKD) with Cr >3 mg/dL (see Chronic Kidney Disease, [[Chronic Kidney Disease]])
  • Malnutrition (BMI <21 kg/m2 in Males/BMI <19 kg/m2 in Females)
  • Mechanical Ventilation (see Mechanical Ventilation-General, [[Mechanical Ventilation-General]])
  • Morbid Obesity (BMI >40 kg/m2) (see Obesity, [[Obesity]])
  • Moderate-Severe Aortic Insufficiency (see Aortic Insufficiency, [[Aortic Insufficiency]])
  • Severe Mitral Stenosis (see Mitral Stenosis, [[Mitral Stenosis]])
  • Uncorrectable Mitral Regurgitation (see Mitral Regurgitation, [[Mitral Regurgitation]])

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

  • Active Systemic Infection/Major Chronic Risk for Infection
  • Abdominal Aortic Aneurysm (AAA) ≥5 cm (see Abdominal Aortic Aneurysm, [[Abdominal Aortic Aneurysm]])
  • Biventricular Heart Failure in Patient >65 y/o
  • Contraindication to Anticoagulation
  • Fixed Portal Hypertension
  • Fixed Pulmonary Hypertension
  • Heparin-Induced Thrombocytopenia (HIT) (see Heparin-Induced Thrombocytopenia, [[Heparin-Induced Thrombocytopenia]])
  • High Surgical Risk for Successful Implantation
  • Impending Hepatic Failure
  • Impending Renal Failure
  • Multiorgan Failure
  • Neurologic Deficits Which May Impair the Ability to Manage the Device
  • Potentially Reversible Cause of Heart Failure
  • Recent/Evolving Stroke (see Ischemic Cerebrovascular Accident, [[Ischemic Cerebrovascular Accident]])
  • Severe Pulmonary Disease (FEV1 <1L)
  • Significant Psychiatric Illness or Lack of Social Support Which May Impair the Ability to Manage Device
  • Terminal Condition
    • Cirrhosis/End-Stage Liver Disease (see Cirrhosis, [[Cirrhosis]])
    • Metastatic Cancer

Physiology

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

Technique

Anticoagulation/Anti-Platelet Agents

  • Required for LVAD

Ventricular Assist Device (VAD) Parameters

Device Parameters to Set

  • Pump Speed (RPM) is the Only Parameter Set by the Physician
    • For HeartMate II Device, Pump Speed Can Be Set Between 6k-15k RPM to Achieve Blood Flow Up to 10 L/min
    • Other Variables (Below) Which are Displayed by the Machine (Including Power, Flow, and Pulsatility) are Dependent on the Patient’s Underlying Physiology

Device Parameters to Monitor

  • Pump Power: direct measurement of the number of watts required by the device to pump blood at the set RPM
    • Pump Power Generally Correlates Well with Blood Flow (with Some Exceptions, as Noted Here)
    • Etiology of Increased Pump Power Required
      • Pump Thrombosis
  • Blood Flow: calculated based on the measured pump power and the the set pump speed
    • Blood Flow Depends on the Pump Speed and the Pressure Differential (Head Pressure) Across the Pump
      • At a Given Pump Speed, the Difference Between Mean Arterial Pressure (Afterload) and the Left Ventricular Chamber Pressure (Preload) Correlates Inversely with Blood Flow
        • Although the Greatest Determinant of Pump Differential Pressure is the LV Intracavitary Pressure, Increased Vascular Tone (Afterload) Can Also Decrease Blood Flow
      • During Exercise
        • Systemic Vascular Resistance (Afterload) Decreases, Resulting in a Decreased Pump Differential During Systole
        • Blood Flow Will Therefore, Increase, Even at a Given Pump Speed
    • Calculated Blood Flow May Underestimate Cardiac Output, Since it Does not Account for Blood Ejected by the Native LV Across the Aortic Valve
    • Device-Specific Considerations
      • For HeartMate II Devices, Calculated Flows are Inaccurate with Pump Speeds ≤8000 RPM
      • For HeartWare Devices, Blood Viscosity Significantly Impacts Flow: consequently, hematocrit is integrated into its algorithm
    • Etiology of Decreased Blood Flow
      • Arrhythmia
        • Address by Treating Arrhythmia
      • Hypovolemia/Hemorrhage (see Hypovolemic Shock, [[Hypovolemic Shock]] and Hemorrhagic Shock, [[Hemorrhagic Shock]])
        • Address with Intravenous Fluids/Packed Red Blood Cells
    • Etiology of Increased Blood Flow
      • Vasodilation
        • Address by Decreasing Vasodilator Dosage
      • Sepsis (see Sepsis, [[Sepsis]])
        • Address by Treating Sepsis with Vasopressors, etc
  • Pulsatility Index (PI): mathematical difference between the maximal and minimal flows divided by the average flow per cardiac cycle
    • Normal PI: 3.5-5.5
    • PI is Largely Dependent on the Intrinsic LV Performance and Preload
    • Device-Specific Considerations
      • When the HeartMate II Detects a Abrupt Decrease in PI, it Automatically Decreases the Pump Speed to the Lower Limit Pump Speed Set by the Operator (Which Serves to Ameliorate the Suction Event)
      • HeartWare Device Does Not Mathematically Calculate the Pulstatility (But Flow and Pulsatility is Shown Graphically on the Display
    • Etiology of Decreased PI
      • Decreased LV Contractility
        • Address by Adding Inotropic Support
      • Excessive Pump Speed
        • Address by Decreasing Pump Speed
      • Hypovolemia/Hemorrhage (see Hypovolemic Shock, [[Hypovolemic Shock]] and Hemorrhagic Shock, [[Hemorrhagic Shock]])
        • Address with Intravenous Fluids/Packed Red Blood Cellls
      • Outflow Cannula Obstruction
    • Etiology of Increased PI
      • Percutaneous Lead Damage
        • Assess VAD Components
      • Recovery of Left Ventricular Function

Other Problems

  • Suction Event: defined as the VAD pulling out more blood than the LV can supply
    • Clinical Features of Suction Event
      • Collapse of Ventricular Cavity Around Device Inflow
      • Shift of the Intraventricular Septum and Partial Obstruction of the LV Outflow Cannula
      • Contact Between the Cannula and the LV Wall Can Trigger Ventricular Tachycardia
      • Sudden Decrease in PI (Since Pump Flow Decreases)
        • May Be Associated with Low Flows, Low PI, or Alarms
    • Etiology of Suction Event
      • Ventricular Tachycardia (VT): due to a decrease in LV preload
        • Address by Treating Arrhythmia
      • Excessive Unloading of Ventricle by the VAD
        • Lower Pump Speed
      • Hypovolemia (see Hypovolemic Shock, [[Hypovolemic Shock]]): most common etiology
        • Address with Intravenous Fluids

Physical Exam Findings

  • Absence of Peripheral Pulses: due to continuous flow VAD

Blood Pressure Management

General Comments

  • MAP is Usually Maintained at 70-90 mm Hg
    • Assuming Adequate Intracavitary Volume, Increasing Pump Speed Will Increase Mean Arterial Pressure and Diastolic Blood Pressure (without Changing the Systolic Blood Pressure)
    • Excessive Blood Pressure is Associated with Neurologic Events, Hemorrhage, and Decreased Blood Flow

Blood Pressure Measurement

  • Non-Invasive Blood Pressure Cuff
    • Unreliable and Values Usually Underestimate the Mean Arterial Pressure (MAP) and Systolic Blood Pressure (SBP)
    • Occlusion Pressures Obtained by Doppler at the Brachial Artery Usually Correlate Well with Invasive Arterial Blood Pressure Measurements
      • This Measurement Reflects the Mean Arterial Pressure, But Not the Systolic Blood Pressure
  • Arterial Line (see Arterial Line, [[Arterial Line]])
    • Usually Required in the Immediate Post-Operative Period, During Shock, and to Assesss Device Function

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

  • Disadvantages
    • Pulse Oximetry May Be Unreliable in the Setting of Minimal/Absent Pulse

Echocargiogram (see Echocargiogram, [[Echocargiogram]])

  • Clinical Utility
    • Echocardiogram May Be Used to Assess Septal Position and Chamber Size (Both of Which May Guide Pump Speed Adjustments)
    • Echocardiogram May Be Used to Assess Aortic Valve Opening to Determine the Contribution of Native Cardiac Function to Overall Output

Adverse Effects/Complications

General Comments

  • Complications Requiring Hospitalization are Common with VAD’s
    • Dcereasing Frequency of Complications Occurs within the First 6 mo of Implantation, with Subsequent Stabilization (J Am Coll Cardiol, 2013) [MEDLINE]
    • Most Common Adverse Effects/Complications (J Am Coll Cardiol, 2013) [MEDLINE]
      • Arrhythmia
      • Congestive Heart Failure
      • Hemorrhage
      • Infection
      • Thrombosis

Cardiovascular Adverse Effects/Complications

Left Ventricular Thrombus/Thromboembolic Complications

  • Epidemiology: occurs in 10-16% of cases
    • Rate of Pump Thrombosis with HeartMate II Has Recently Been Noted to Increase from 2.2% to 8.4% (NEJM, 2014) [MEDLINE]
      • Median Time from Implantation to Thrombosis Decreased from 18.6 mo to 2.7 mo
      • Pump Thrombosis was Presaged by an Increase in LDH within the Weeks Before Diagnosis
      • Pump Thrombosis was Managed by Either Pump Replacement or Heart Transplantation
      • Mortality Rate Among Patients with Pump Thrombosis Who Did Not Undergo Pump Replacement or Heart Transplantation was 48.2% in the 6 mo After Pump Thrombosis
  • Risk Factors for Pump Thrombosis
    • Declining Renal Function
    • Development of Thrombus or Myocardial Infarction Before Device Implantation
    • Large Stature
    • Left Atrial Cannulation
    • Less Severe Ventricular Dysfunction
    • Marked LDH Elevation 1 mo Post-Implantation
    • Post-Implantation Hemorrhage
    • Recent Implantation: risk of thrombosis appears to be highest within the first 6 mo
    • Younger Age
  • Diagnosis
    • Echocardiogram (see Echocardiogram, [[Echocardiogram]]): useful to detect pump thrombosis
    • Cardiac CT (see Cardiac Computed Tomography, [[Cardiac Computed Tomography]]): may be more reliable means of detecting pump thrombosis (sensitivity = 85%, specificity = 100%)
  • Clinical
    • Evidence of Increased Hemolysis (Manifested by Increased LDH): may be an early harbinger of pump thrombosis
    • Evidence of Increased Pump Power Utilization: may be an early harbinger of pump thrombosis
    • Evidence of Worsened Heart Failure Symptoms
    • Systemic Embolization
  • Treatment
    • Heparin Anticoagulation in Anticipation of LVAD Explantation/Reimplantation (see Heparin, [[Heparin]]): commonly used strategy with the lowest mortality rate (around 5%)
    • Lepirudin (XXXX) (see Lepirudin, [[Lepirudin]])
    • Thrombolytics: has been described, but has very high mortality rate (up to 50%)

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

  • Epidemiology
    • Definition of RV Dysfunction: need for right ventricular support (pharmacologic or mechanical) for >14 days after LVAD implantation
    • RV Dysfunction iOccurs in 20-30% of Patients Receiving LVAD’s (Cardiovasc Surg, 2000) [MEDLINE]
    • RV Dysfunction After Implantation Predicts Poorer LVAD Outcome
  • Pre-Operative Risk Factors (Mayo Clin Proc, 2016) [MEDLINE]
    • Anemia (see Anemia, [[Anemia]])
    • Echocardiographic Indicators of Right Ventricular Dysfunction
    • Elevated Filling Pressures
    • Hepatic Dysfunction
    • Renal Dysfunction
    • Requirement for Intra-Aortic Balloon Pump Support (IABP)
  • Physiologic Mechanisms of RV Dysfunction After LVAD Placement
    • Altered Interventricular Balance
    • Excessive Right Ventricular Preload
    • Leftward Shift of Intraventricular Septum
    • Perioperative Fluctuations in Pulmonary Vascular Resistance
    • Preoperative RV Dysfunction and Pulmonary Hypertension: preexisting RV dysfunction increases the susceptibility of the RV to further decline after LVAD implantation
    • RV Ischemia: although the RV is generally less susceptible to ischemia than the LV (due to less myocardial mass and a more favorable oxygen supple/demand ratio)
  • Considerations: however, since preexisting RV dysfunction can be managed, it is not an absolute contraindication to LVAD implantation

Ventricular Arrhythmias

  • Epidemiology
    • Incidence of Arrhythmias is Highest in the First Month After Implantation
  • Physiologic Mechanisms
    • Cannula Malposition: may occur months after implantation due to migration of the device associated with change in body weight or development of scar tissue
    • Contact Between the Cannula and the Ventricular Septum During Hypovolemia, RV Failure, or Small Ventricular Size
    • Creation of Reentrant Circuit by Placement of the LVAD Cannula
    • Mechanical Irritation of the Left Ventricle
  • Clinical
  • Treatment
    • First, Decrease the LVAD Speed to Allow for Increased Ventricular Filling: this may shift the cannula away from the ventricular wall
    • Treat Hypovolemia with Intravenous Fluids
    • Antiarrhythmics

Gastrointestinal Adverse Effects/Complications

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

  • Epidemiology
    • Continuous-Flow LVAD: bleeding rate is 63 per 100 patient-years (ASAIO J, 2010) [MEDLINE]
      • Increased Bleeding Risk May Be Due to Acquired Von Willebrand Syndrome Secondary to Cleavage of Large Von Willebrand Factor Multimers into Smaller Multimers in the Pump: smaller multimers are cleared more readily, leading to lower levels of Von Willebrand factor
    • Pulsatile-Flow LVAD: bleeding rate is 6.8 per 100 patient-years (ASAIO J, 2010) [MEDLINE]
    • Specific Etiologies of Gastrointestinal Hemorrhage
      • Arteriovenous Malformation
      • Gastroesophageal Reflux with Erosions
      • Gastrostromy/Feeding Tube
      • Polyp
  • Physiology
    • Anticoagulation
    • Effect of Pump on Von Willebrand Factor: as noted above

Hematologic Adverse Effects/Complications

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

  • Epidemiology: occurs in most patients (although is generally not severe)

Hemorrhage

  • Epidemiology
    • Hemorrhage is the Most Common Complication of VAD Implantation
      • Early Bleeding Requiring Repeat Surgery Occurs in 26% of Cases
    • Most Common Sites of Early Hemorrhage
      • Chest Wall Hemorrhage
      • Gastrointestinal Hemorrhage (see Gastrointestinal Hemorrhage, [[Gastrointestinal Hemorrhage]])
      • Mediastinal Hemorrhage: most common early site of hemorrhage
      • Pleural Space
    • Most Common Sites of Hemorrhage >30 Days After Implantation
      • Epistaxis (see Epistaxis, [[Epistaxis]])
      • Gastrointestinal Hemorrhage (see Gastrointestinal Hemorrhage, [[Gastrointestinal Hemorrhage]])
      • Intracranial Hemorrhage
      • Mediastinal Hemorrhage
      • Pleural Space
  • Treatment
    • Use Only Leukoreduced, Irradiated Blood Products in Patients Being Considered for Future Cardiac Transplantation

Thrombocytopenia (see Thrombocytopenia, [[Thrombocytopenia]])

  • Epidemiology: occurs in 7% of cases

Infectious Adverse Effects/Complications

Infection (see Sepsis, [[Sepsis]])

  • Epidemiology
    • Infection Occurs in 50% of Cases
    • Infection is the Second Most Common Cause of Death (After Heart Failure) in Patients with VAD’s
  • Mechanisms
    • Presence of Foreign Body
    • Impairment of T-Cell Function
  • Prevention: continuous antimicrobial treatment before/during/after transplantation was associated with fewer relapses compared to a limited course of antibiotics
  • Prognosis
    • Infection May Be Fatal
    • However, Infection Does Not Preclude Transplantation

Neurologic Adverse Effects/Complications

Intracranial Hemorrhage


Prognosis

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

  • Platelet Count ≤148k: risk score = 7
  • Serum Albumin ≤3.3 g/dL: risk score = 5
  • INR >1.1: risk score = 4
  • Vasodilator Therapy: risk score = 4
  • PA Mean ≤25 mm Hg: risk score = 3
  • AST >45 IU/mL: risk score = 2
  • Hct ≤34%: risk score = 2
  • BUN >51 U/dL: risk score = 2
  • No Intravenous Inotropes: risk score = 2

Destination Therapy Risk Score

  • Low Risk: score 0-8
  • Medium-High Risk: score 9-19
  • Very High Risk: score >19

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

  • Older Age
  • Female Sex
  • Higher BMI
  • High BUN and Creatinine
    • Baseline Creatinine Predicts Survival After LVAD
  • History of Dialysis
  • History of Stroke
  • Hypoalbuminemia
  • Implantation for Destination Therapy
  • Lower Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Class
  • Previous Cardiac Surgery
  • Signs of Right-Sided Heart Dysfunction (High Central Venous Pressure, Elevated Bilirubin, Ascites, or Concurrent RVAD)

References

  • Postoperative acute refractory right ventricular failure: incidence, pathogenesis, management and prognosis. Cardiovasc Surg 2000, 8(1):1-9 [MEDLINE]
  • REMATCH Trial. Long-term use of a left ventricular assist device for end-stage heart failure. N Engl J Med. 2001;345(20):1435 [MEDLINE]
  • Use of a continuous-flow device in patients awaiting heart transplantation. N Engl J Med 2007; 357:885.
  • Chronic mechanical circulatory support for inotrope-dependent heart failure patients who are not transplant candidates: results of the INTrEPID Trial. J Am Coll Cardiol 2007; 50:741
  • Use of continuous-flow device in patients awaiting heart transplantation.  N Engl J Med  2007;357:885–896 [MEDLINE]
  • Advanced heart failure treated with continuous-flow left ventricular assist device. N Engl J Med 2009; 361:2241.
  • Extended mechanical circulatory support with a continuous-flow rotary left ventricular assist device. J Am Coll Cardiol 2009; 54:312
  • Evaluation for a ventricular assist device: selecting the appropriate candidate.  Circulation 2009;119:2225–2232 [MEDLINE]
  • Heartmate II axial-flow left ventricular assist system: management, clinical review and personal experience. J Cardiovasc Med (Hagerstown). 2009 Oct;10(10):765-71. doi: 10.2459/JCM.0b013e32832d495e [MEDLINE]
  • Comparative analysis of von Willebrand factor profiles in pulsatile and continuous left ventricular assist device recipients. ASAIO J. 2010;56(5): 441-445 [MEDLINE]
  • Right ventricular failure—a continuing problem in patients with left ventricular assist device support.  J Cardiovasc Transl Res 2010;3:604–611 [MEDLINE]
  • Management of right ventricular failure in the era of ventricular assist device therapy.  Curr Heart Fail Rep  2011;8:65-71 [MEDLINE]
  • Who needs an RVAD in addition to an LVAD?  Cardiol Clin.  2011;29:599–605 [MEDLINE]
  • Survival after biventricular assist device implantation: an analysis of the Interagency Registry for Mechanically Assisted Circulatory Support database. J Heart Lung Transplant. 2011 Aug;30(8):862-9. Epub 2011 May 31 [MEDLINE]
  • Results of the post-U.S. Food and Drug Administration-approval study with a continuous flow left ventricular assist device as a bridge to heart transplantation: a prospective study using the INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support). J Am Coll Cardiol 2011; 57:1890
  • Multicenter evaluation of an intrapericardial left ventricular assist system. J Am Coll Cardiol 2011; 57:1375.
  • Use of an intrapericardial, continuous-flow, centrifugal pump in patients awaiting heart transplantation. Circulation 2012; 125:3191.
  • Outcomes in advanced heart failure patients with left ventricular assist devices for destination therapy. Circ Heart Fail 2012; 5:241
  • Magnitude and time course of changes induced by continuous-flow left ventricular assist device unloading in chronic heart failure: insights into cardiac recovery. J Am Coll Cardiol. 2013;61(19):1985 [MEDLINE]

  • Readmissions after implantation of axial ow left ventricular assist device. J Am Coll Cardiol 2013; 61:153–163 [MEDLINE]

  • Unexpected abrupt increase in left ventricular assist device thrombosis. N Engl J Med. 2014;370:33–40. doi: 10.1056/NEJMoa1313385. Epub 2013 Nov 27 [MEDLINE]

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