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 but have evolved into permanent, or “destination therapy | *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 | *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> | ||
*Goal of a VAD is to assist the ventricle and augment cardiac output | *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> | **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 | |||
#Speed | *#Flow | ||
#Flow | *#Power | ||
#Power | |||
===Components=== | ===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 | *'''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) | *'''Driveline''' = Percutaneous cable that exits the abdominal wall, connects pump to external components (controller, battery) | ||
*'''Controller''' = External "box" containing computer | *'''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 | *'''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=== | ===Devices Overview=== | ||
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***Place pads anterior/posterior if going to cardiovert/defibrillate | ***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) | *Assess perfusion and general state (mental status, skin temp/color, capillary refill, etc) | ||
**LVADs are preload dependant - if symptoms of hypoperfusion, give fluid blous | **LVADs are preload dependant - if symptoms of hypoperfusion, give fluid blous | ||
*HR measured via ECG or auscultation (may be difficult secondary to pump noise) | *HR measured via ECG or auscultation (may be difficult secondary to pump noise) | ||
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*Take special care to not twist, bend, cut, or otherwise damage the driveline | *Take special care to not twist, bend, cut, or otherwise damage the driveline | ||
*First generation LVADs had pulsatile flow | *First generation LVADs had pulsatile flow | ||
**Subsequent designs use continuous flow - patient will not have a palpable pulse | **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 | *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) | *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" /> | **ICD discharges are common, and frequently inappropriate (possibly secondary to LVAD interference)<ref name="LVAD 2" /> | ||
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**Some first-generation LVADs have external hand pumps that can be used to provide circulation | **Some first-generation LVADs have external hand pumps that can be used to provide circulation | ||
*Otherwise follow [[ACLS]] as in a normal patient | *Otherwise follow [[ACLS]] as in a normal patient | ||
**Patient should be intubated, given IV fluids and drugs, etc | **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 | *'''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 | **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 | **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 | **Use clinical judgement for initiation of compressions | ||
==Disposition== | ==Disposition== | ||
*Immediately contact the patient's VAD coordinator | *Immediately contact the patient's VAD coordinator | ||
*Almost all LVAD patient presenting to the ED will require admission | *Almost all LVAD patient presenting to the ED will require admission | ||
==See Also== | ==See Also== | ||
Revision as of 01:44, 28 July 2016
Background
- 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:
- Speed
- Flow
- 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 or XVE
- Use: Destination Therapy
- Flow Type: Pulsatile
- Backup Method: Hand Pump
- Battery: 12volt MiMH - 10hrs
- Defib/Cardioversion: Use hand pump during defib/cardioversion
HeartMate II
(Most common type in use today)
- Use: Bridge to transplant or destination therapy
- Flow type: Continuous
- Backup Method: No external method
- Battery: 14V Li-Ion - 10 hrs
- Defib/Cardioversion: No precautions
Thoratec VAD
- 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
Differential Diagnosis[3]
- Bleeding - most common reason for ED visit (frequency 42%[4])
- GI Bleed, epistaxis, ICH, intrathoracic bleeding
- Mechanisms
- acquired Von Willebrands Disease
- supratherapeutic anticoagulation
- lack of pulsatile flow → AV malformations in GI tract
- Immediately consult VAD team/coordinator
- Tx - anticoagulation reversal based on specific agents used
- In life-threatening bleeds, consider TXA, PCC, Desmopressin, FFP
- Coumadin reversal carries low risk for acute thrombosis [5]
- Infection - driveline and pocket are most common sites[4]
- 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
- Dx with echo or cardiac CTA
- Tx with heparin and antiplatelet therapy
- Consider tPA in severe (life-threatening) situations
- Arrhythmia - very common
- Get labs to evaluate electrolytes and troponin
- Tx atrial fibrillation as in any other patient
- Tx ventricular arrhythmias with volume replacement and pharmacological or electrical cardioversion
- Place pads anterior/posterior if going to cardiovert/defibrillate
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
- 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
- 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[7][8] indicate that CPR may not be as harmful as currently thought, or that abdominal compressions are an alternative[9] 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
- ↑ Mancini D, Lietz K. Selection of cardiac transplantation candidates in 2010. Circulation. 2010;122(2):173-83.
- ↑ Mechem CC. Prehospital assessment and management of patients with ventricular-assist devices. Prehosp Emerg Care. 2013 Apr-Jun;17(2):223-9.
- ↑ 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.
- ↑ 4.0 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.
- ↑ 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
- ↑ 6.0 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
- ↑ 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.
- ↑ 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.
- ↑ 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.