Left ventricular assist device complications: Difference between revisions

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==Background==
==Background==
*Developed in 1960s and used as a bridge to Cardiac Transplant
*Commonly referred to as an LVAD
*Indication is New York Heart Association class 4 heart failure, ejection fraction <25%, VO2 max less than 15 among other criteria.<ref>Mancini D, Lietz K. Selection of cardiac transplantation candidates in 2010. Circulation. 2010;122(2):173-83.</ref>
*Developed in 1960s and used as a bridge to Cardiac Transplant but have evolved into permanent, or “destination therapy"
*All VADs are pre-load dependent.
*Indication is New York Heart Association class 4 heart failure, ejection fraction <25%, VO2 max less than 15 among other criteria<ref>Mancini D, Lietz K. Selection of cardiac transplantation candidates in 2010. Circulation. 2010;122(2):173-83.</ref>
*VADs are ECG independent, unlike ICDs.
*Goal of a VAD is to assist the ventricle and augment cardiac output
**LVAD (left ventricle), RVAD (right ventricle), BiVAD (both venticles via separate pumps)<ref name="LVAD Prehospital">Mechem CC. Prehospital assessment and management of patients with ventricular-assist devices. Prehosp Emerg Care. 2013 Apr-Jun;17(2):223-9.</ref>
*VADs have 3 major variables:
*#Speed
*#Flow
*#Power


:VADs have 3 major variables:
===Components===
#Speed
*'''Pump''' = Internal pump (usually placed in preperitoneal space), takes blood from a cannula in the apex of the left ventricle and pumps it into the aorta
#Flow
*'''Driveline''' = Percutaneous cable that exits the abdominal wall, connects pump to external components (controller, battery)
#Power
*'''Controller''' = External "box" containing computer for the device that monitors pump performance, has a display screen and controls for settings/alarms/diagnostics, and will display will show pump speed in RPM and pump output in L/min
*'''Power Supply''' = Controller can be connected to batteries for patient mobility, or to a "power base station" that plugs into the wall for home use


==Mechanism of Action==
===Devices Overview===
*External pump unit outside body with intake channel (blood is drained from the apex of the left ventricle) and output channel (blood is ejected into the aorta). Bypasses left ventricle function. BiVAD bypasses both ventricles.
 
==Special Considerations==
*Patient does not have a pulse due to the mechanics of the device
*Listen to the heart to hear if the pump is working


[[File:Heartmate i.png|thumb|Heartmate I]]
[[File:Heartmate i.png|thumb|Heartmate I]]
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[[File:Thoratec.jpg|thumb|Thoratec-VAD]]
[[File:Thoratec.jpg|thumb|Thoratec-VAD]]


==Complications==
====HeartMate I or XVE====
#Driveline/Pocket infections: Treat for gram negative and positive coverage. Consider endocarditis for recently transplanted pts.
#'''Use:''' Destination Therapy
#Pump Thrombosis (due to inappropriate anticoagulation)
#'''Flow Type:''' Pulsatile
##Consider heparin/tPA if device thrombus is a high probability or seen on bedside echo
#'''Backup Method:''' Hand Pump
#Bleeding (many patients are anticoagulated on the LVAD)
#'''Battery:''' 12volt MiMH - 10hrs
##Acquired Von Willebrand disease (similar to patients on dialysis or with aortic stenosis)
#'''Defib/Cardioversion:''' Use hand pump during defib/cardioversion
##Hypercoagulability due to coumadin
 
#Dead Battery for Device
====HeartMate II====
##Usually a button to check remaining battery charge
('''Most common type in use today''')
#Arrythmias: Okay to defibrillate (front-to-back), but not over pump
#'''Use:''' Bridge to transplant or destination therapy
#Acute Infarction
#'''Flow type:''' Continuous
#'''Backup Method:''' No external method
#'''Battery:''' 14V Li-Ion - 10 hrs
#'''Defib/Cardioversion:''' No precautions
 
====Thoratec VAD (HeartMate III)====
#'''Use:''' Bridge to Transplant
#'''Flow Type:''' Pulsatile
#'''Backup Method:''' No external method
#'''Battery:''' 12V lead acid gel battery - 7.2 Ah - up to 3 hrs
#'''Defib/Cardioversion:''' No precautions
 
==Complications/Differential Diagnosis<ref name="LVAD" />==
*Bleeding - most common reason for ED visit (frequency 42%<ref name="REMATCH">Rose EA, Gelijns AC, Moskowitz AJ et al. Long-term use of a left ventricular assist device for end-stage heart failure. N. Engl. J. Med. 2001; 345: 1435–1443.</ref>)
**[[GI Bleed]], [[epistaxis]], [[ICH]], intrathoracic bleeding
**Mechanisms:
***Acquired [[Von Willebrand Disease (vWD)]]
***[[Coagulopathy (main)|supratherapeutic anticoagulation]]
***Lack of pulsatile flow → AV malformations in GI tract
**Immediately consult VAD team/coordinator
**Treatment - [[anticoagulant]] reversal based on specific agents used
***In life-threatening bleeds, consider [[TXA]], [[PCC]], [[Desmopressin]], [[FFP]]
***[[Warfarin reversal]] carries low risk for acute thrombosis <ref>Jennings, D, et al. Safety of Anticoagulation Reversal in Patients Supported with Continuous-Flow Left Ventricular Assist Devices. ASAIO Journal. July 2014. 60:381–384</ref>
*Infection - driveline and pocket are most common sites<ref name="REMATCH" />
**Usually [[gram positive bacteria]], but also need to cover for [[fungal infection]]
*Pump Thrombosis
**Low output state with falsely elevated pump flow estimates on controller
**Diagnose with echo or cardiac CTA
**Treatment with [[heparin]] and [[antiplatelet]] therapy
**Consider [[tPA]] in severe (life-threatening) situations
*[[Arrhythmia]] - very common
**Get labs to evaluate electrolytes and troponin
**Treatment [[atrial fibrillation]] as in any other patient
**Treatment ventricular arrhythmias with volume replacement and pharmacological or electrical cardioversion
***Place pads anterior/posterior if going to cardiovert/defibrillate
 
==Evaluation<ref name="LVAD">Partyka C, Taylor B. Review article: ventricular assist devices in the emergency department. Emerg Med Australas. 2014 Apr;26(2):104-12.</ref>==
*Assess perfusion and general state (mental status, skin temp/color, capillary refill, etc)
**LVADs are preload dependant - if symptoms of hypoperfusion, give fluid blous
*HR measured via ECG or auscultation (may be difficult secondary to pump noise)
*Get 12-lead ECG on all LVAD patients
**Demonstrates primary cardiac disease<ref name="LVAD 2">Pistono M, Corrà U, Gnemmi M, Imparato A, Temporelli PL, Tarro Genta F, Giannuzzi P. How to face emergencies in heart failure patients with ventricular assist device. Int J Cardiol. 2013 Oct 15;168(6):5143-8</ref>
**Generally, VAD does not influence underlying cardiac rhythm
*Bedside echo if able, formal echo if available
*Blood pressure measured with manual BP cuff and Doppler ultrasound - MAP is identified when constant flow is heard
**MAP should be 70-90 mmHg
**Can also monitor with [[arterial line]]
*Basic labs (CBC, CMP, Coags) should be obtained on all LVAD patients
*LDH elevation over 1,150 IU/L suggestive of pump thrombosis<ref>Zoler ML. Cardiology News. STS: Lactate dehydrogenase of 1,150 IU/L flags LVAD thrombosis. https://www.mdedge.com/ecardiologynews/article/106621/heart-failure/sts-lactate-dehydrogenase-1150-iu/l-flags-lvad. Published Feb 19, 2016.</ref>
**Approximate sensitivity of ~80% and specificity of 90%
**Hemolysis within thrombosed pump releases LDH
*Assess LVAD status
**Auscultate for pump noise
**Device parameters (found on controller)
***'''Pump speed''' - varies by device - 2,000-10,000 RPM
***'''Power''' - normal 4-6 Watts
***'''Flow''' - normal 4-6 L/min
***'''Pulsatility Index (PI)''' - normal 1-10
****Measures magnitude of pulsatile flow provided by native cardiac contractions
****Higher PI = less LVAD support
**Clinical status more important than LVAD parameters
 
==Management==
*Immediately contact hospital or patient's LVAD coordinator to help coordinate care
*Take special care to not twist, bend, cut, or otherwise damage the driveline
*First generation LVADs had pulsatile flow
**Subsequent designs use continuous flow - patient will not have a palpable pulse
*Patient will be on anticoagulation and antiplatelet therapy secondary to high risk of pump thrombus, CVA, and other thromboembolic events
*VADs are ECG independant, unlike ICD (many patients with a VAD will also have an ICD in place)
**ICD discharges are common, and frequently inappropriate (possibly secondary to LVAD interference)<ref name="LVAD 2" />
 
===Cardiac Arrest<ref name="LVAD" />===
*Unconscious, apneic, no evidence of LVAD function (auscultate for mechanical noise)
*Immediately evaluate LVAD components and attach to reliable power source
**Some first-generation LVADs have external hand pumps that can be used to provide circulation
*Otherwise follow [[ACLS]] as in a normal patient
**Patient should be intubated, given IV fluids and drugs, etc
*'''Avoid chest compressions unless absolutely necessary''' - evaluate other causes of pump failure or lack of perfusion (e.g. pump thrombus) first
**Compressions can potentially damage LVAD, disrupt its connection to the heart (risk of exsanguination), etc
**Some studies available<ref>Shinar Z, Bellezzo J, Stahovich M, Cheskes S, Chillcott S, Dembitsky W. Chest compressions may be safe in arresting patients with left ventricular assist devices (LVADs). Resuscitation. 2014 May;85(5):702-4.</ref><ref>Mabvuure NT, Rodrigues JN. External cardiac compression during cardiopulmonary resuscitation of patients with left ventricular assist devices. Interact Cardiovasc Thorac Surg. 2014 Aug;19(2):286-9.</ref> indicate that CPR may not be as harmful as currently thought, or that abdominal compressions are an alternative<ref>Eric M Rottenberg, Jarrett Heard, Robert Hamlin, Benjamin C Sun, and Hamdy Awad. Abdominal only CPR during cardiac arrest for a patient with an LVAD during resternotomy: A case report. J Cardiothorac Surg. 2011; 6: 91.</ref> but further investigation needed
**Use clinical judgement for initiation of compressions


==Devices Overview==
==Disposition==
*Immediately contact the patient's VAD coordinator
*Almost all LVAD patient presenting to the ED will require admission


#'''HeartMate I or XVE'''
==See Also==
##'''Use:''' Destination Therapy
*[[ACLS (Main)]]
##'''Flow Type:''' Pulsatile
##'''Pulse:''' Has pulse but may not match ECG rhythm
##'''Backup Method:''' Hand Pump
##'''Battery:''' 12volt MiMH - 10hrs
##'''Defib/Cardioversion:''' Use hand pump during defib/cardioversion
##'''Anticoagulation:''' patient on aspirin
#'''HeartMate II'''
##'''Use:''' Bridge to transplant or destination therapy
##'''Flow type:''' axial flow
##'''Backup Method:''' No external method
##'''Pulse:''' No palpable pulse or BP.  Dopplerable Only
##'''Battery:''' 14V Li-Ion - 10 hrs
##'''Defib/Cardioversion:''' No precautions necessary
##'''Anticoagulation:''' Warfarin


#'''Thoratec VAD'''
==External Links==
##'''Use:''' Bridge to Transplant
*[http://marylandccproject.org/2013/12/12/introduction-ventricular-assist-devices/ VAD Review]
##'''Flow Type:''' Patient will have pulse and BP but may not match ECG rhythm
*[http://emcrit.org/wee/left-ventricular-assist-devices-lvads/ EMCrit LVAD Management]
##'''Backup Method:''' No external method
*[http://www.mylvad.com/sites/mylvadrp/files/Field%20Guides%20Master%20Document.pdf Mechanical Circulatory Support Organization EMS Guide]
##'''Battery:''' 12V lead acid gel battery - 7.2 Ah - up to 3 hrs
##'''Defibrillation/Cardioversion:''' No precautions
##'''Anticoagulation:''' Warfarin


==Sources==
==References==
*[http://mylvad.com/assets/ems_docs/00003528-2012-field-guide.pdf mylvad pdf]
<references/>
*Slaughter MS, Pagani FD, Rogers JG, et al. Clinical management of continuous-flow left ventricular assist devices in advanced heart failure. J Heart Lung Transplant. 2010;29(4 Suppl):S1-39.
*[http://www.emdocs.net/ventricular-assist-device-management/ EMdocs VAD Review]


[[Category:Cards]] [[Category:EMS]]
[[Category:Cardiology]]  
[[Category:EMS]]

Revision as of 23:58, 17 October 2018

Background

  • Commonly referred to as an LVAD
  • Developed in 1960s and used as a bridge to Cardiac Transplant but have evolved into permanent, or “destination therapy"
  • Indication is New York Heart Association class 4 heart failure, ejection fraction <25%, VO2 max less than 15 among other criteria[1]
  • Goal of a VAD is to assist the ventricle and augment cardiac output
    • LVAD (left ventricle), RVAD (right ventricle), BiVAD (both venticles via separate pumps)[2]
  • VADs have 3 major variables:
    1. Speed
    2. Flow
    3. Power

Components

  • Pump = Internal pump (usually placed in preperitoneal space), takes blood from a cannula in the apex of the left ventricle and pumps it into the aorta
  • Driveline = Percutaneous cable that exits the abdominal wall, connects pump to external components (controller, battery)
  • Controller = External "box" containing computer for the device that monitors pump performance, has a display screen and controls for settings/alarms/diagnostics, and will display will show pump speed in RPM and pump output in L/min
  • Power Supply = Controller can be connected to batteries for patient mobility, or to a "power base station" that plugs into the wall for home use

Devices Overview

Heartmate I
Heartmate II
Thoratec-VAD

HeartMate I or XVE

  1. Use: Destination Therapy
  2. Flow Type: Pulsatile
  3. Backup Method: Hand Pump
  4. Battery: 12volt MiMH - 10hrs
  5. Defib/Cardioversion: Use hand pump during defib/cardioversion

HeartMate II

(Most common type in use today)

  1. Use: Bridge to transplant or destination therapy
  2. Flow type: Continuous
  3. Backup Method: No external method
  4. Battery: 14V Li-Ion - 10 hrs
  5. Defib/Cardioversion: No precautions

Thoratec VAD (HeartMate III)

  1. Use: Bridge to Transplant
  2. Flow Type: Pulsatile
  3. Backup Method: No external method
  4. Battery: 12V lead acid gel battery - 7.2 Ah - up to 3 hrs
  5. Defib/Cardioversion: No precautions

Complications/Differential Diagnosis[3]

Evaluation[3]

  • Assess perfusion and general state (mental status, skin temp/color, capillary refill, etc)
    • LVADs are preload dependant - if symptoms of hypoperfusion, give fluid blous
  • HR measured via ECG or auscultation (may be difficult secondary to pump noise)
  • Get 12-lead ECG on all LVAD patients
    • Demonstrates primary cardiac disease[6]
    • Generally, VAD does not influence underlying cardiac rhythm
  • Bedside echo if able, formal echo if available
  • Blood pressure measured with manual BP cuff and Doppler ultrasound - MAP is identified when constant flow is heard
  • Basic labs (CBC, CMP, Coags) should be obtained on all LVAD patients
  • LDH elevation over 1,150 IU/L suggestive of pump thrombosis[7]
    • Approximate sensitivity of ~80% and specificity of 90%
    • Hemolysis within thrombosed pump releases LDH
  • Assess LVAD status
    • Auscultate for pump noise
    • Device parameters (found on controller)
      • Pump speed - varies by device - 2,000-10,000 RPM
      • Power - normal 4-6 Watts
      • Flow - normal 4-6 L/min
      • Pulsatility Index (PI) - normal 1-10
        • Measures magnitude of pulsatile flow provided by native cardiac contractions
        • Higher PI = less LVAD support
    • Clinical status more important than LVAD parameters

Management

  • Immediately contact hospital or patient's LVAD coordinator to help coordinate care
  • Take special care to not twist, bend, cut, or otherwise damage the driveline
  • First generation LVADs had pulsatile flow
    • Subsequent designs use continuous flow - patient will not have a palpable pulse
  • Patient will be on anticoagulation and antiplatelet therapy secondary to high risk of pump thrombus, CVA, and other thromboembolic events
  • VADs are ECG independant, unlike ICD (many patients with a VAD will also have an ICD in place)
    • ICD discharges are common, and frequently inappropriate (possibly secondary to LVAD interference)[6]

Cardiac Arrest[3]

  • Unconscious, apneic, no evidence of LVAD function (auscultate for mechanical noise)
  • Immediately evaluate LVAD components and attach to reliable power source
    • Some first-generation LVADs have external hand pumps that can be used to provide circulation
  • Otherwise follow ACLS as in a normal patient
    • Patient should be intubated, given IV fluids and drugs, etc
  • Avoid chest compressions unless absolutely necessary - evaluate other causes of pump failure or lack of perfusion (e.g. pump thrombus) first
    • Compressions can potentially damage LVAD, disrupt its connection to the heart (risk of exsanguination), etc
    • Some studies available[8][9] indicate that CPR may not be as harmful as currently thought, or that abdominal compressions are an alternative[10] but further investigation needed
    • Use clinical judgement for initiation of compressions

Disposition

  • Immediately contact the patient's VAD coordinator
  • Almost all LVAD patient presenting to the ED will require admission

See Also

External Links

References

  1. ↑ Mancini D, Lietz K. Selection of cardiac transplantation candidates in 2010. Circulation. 2010;122(2):173-83.
  2. ↑ Mechem CC. Prehospital assessment and management of patients with ventricular-assist devices. Prehosp Emerg Care. 2013 Apr-Jun;17(2):223-9.
  3. ↑ 3.0 3.1 3.2 Partyka C, Taylor B. Review article: ventricular assist devices in the emergency department. Emerg Med Australas. 2014 Apr;26(2):104-12.
  4. ↑ 4.0 4.1 Rose EA, Gelijns AC, Moskowitz AJ et al. Long-term use of a left ventricular assist device for end-stage heart failure. N. Engl. J. Med. 2001; 345: 1435–1443.
  5. ↑ Jennings, D, et al. Safety of Anticoagulation Reversal in Patients Supported with Continuous-Flow Left Ventricular Assist Devices. ASAIO Journal. July 2014. 60:381–384
  6. ↑ 6.0 6.1 Pistono M, Corrà U, Gnemmi M, Imparato A, Temporelli PL, Tarro Genta F, Giannuzzi P. How to face emergencies in heart failure patients with ventricular assist device. Int J Cardiol. 2013 Oct 15;168(6):5143-8
  7. ↑ Zoler ML. Cardiology News. STS: Lactate dehydrogenase of 1,150 IU/L flags LVAD thrombosis. https://www.mdedge.com/ecardiologynews/article/106621/heart-failure/sts-lactate-dehydrogenase-1150-iu/l-flags-lvad. Published Feb 19, 2016.
  8. ↑ Shinar Z, Bellezzo J, Stahovich M, Cheskes S, Chillcott S, Dembitsky W. Chest compressions may be safe in arresting patients with left ventricular assist devices (LVADs). Resuscitation. 2014 May;85(5):702-4.
  9. ↑ Mabvuure NT, Rodrigues JN. External cardiac compression during cardiopulmonary resuscitation of patients with left ventricular assist devices. Interact Cardiovasc Thorac Surg. 2014 Aug;19(2):286-9.
  10. ↑ Eric M Rottenberg, Jarrett Heard, Robert Hamlin, Benjamin C Sun, and Hamdy Awad. Abdominal only CPR during cardiac arrest for a patient with an LVAD during resternotomy: A case report. J Cardiothorac Surg. 2011; 6: 91.
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