LVADs: Understanding the Basics
LVADs (Left Ventricular Assist Device) are devices used to move blood from a failing left ventricle into the aorta. They are often seen in end-stage heart failure patients who, despite optimization of medical management, have a poor prognosis. LVADs can be used as a therapy to bridge patient to cardiac transplantation if they qualify or as destination therapy.
- Inner cannula: this is a suction pipe in the left ventricle
- Outflow cannula: pumps blood into the ascending aorta
- Drive line: connects the outflow cannula to the system controller
- System controller: the LVADs computer, which is connected to a power source
- Most LVAD patients do not have a palpable pulse
- Auscultate the chest and listen to the continuous hum of the LVAD
- Measure MAP: Use a doppler over the brachial artery and inflate a manual blood pressure cuff, record the pressure when flow returns during deflation. MAP should be between 70 to 90.
- Consider A-line
- Assess for signs of infection around the driveline
Testing to consider:
CBC, BMP, LFT, pro-BNP
LDH (increased RBC hemolysis, often increased in the setting of pump thrombosis)
INR (usually on Coumadin with goal INR 2-3 to prevent pump thrombosis)
Common problems encountered in the ED
- Acute decompensated heart failure
- Acute right ventricular failure
- Hypertension: consider afterload reduction as this can lead to an obstruction of flow
- Hypotension: patients are preload sensitive and are responsive to fluid boluses
- Pump thrombosis: consider in patients with symptoms of fatigue or cardiogenic shock. This is often seen with low INR and elevated LDH. Consider heparin as systemic thrombolytics are not recommended. This decision should be made in conjunction with the LVAD coordinator.
- Suction events: the inner cannular suctions the left ventricle wall. This is caused by hypovolemia and can lead to arrhythmia or syncope.
- Arrhythmia: ~25% of LVAD patients will experience arrhythmia within 30 days of implantation. Follow ACLS including cardioversion and defibrillation
- GI bleed: 30% of LVAD patients will develop GI bleeds secondary to anticoagulation or thrombocytopenia. They can also develop an acquired von Willebrand’s disease or AVMs in the GI tract.
- Stroke: 17% of LVAD patients will have a stroke but MRI is contraindicated
- Infections: range from pneumonia to sepsis to driveline infections
- Cardiac arrest: check the controller and connect it to a battery, check the driveline, auscultate the heart for the hum. CPR is controversial as there is a theoretical risk of displacing the outflow cannula but can be lifesaving.
Take Home Points
- contact the LVAD coordinator as early as possible
- assure that the patient has additional batteries and access to a power source
- Transfer to LVAD center when patient is stable
Alvarez PA, McClelland MC, Guha A. Left Ventricular Assist Device (LVAD) Assessment. In: Reichman EF. eds. Reichman's Emergency Medicine Procedures, 3e. McGraw-Hill; Accessed September 07, 2020. https://accessemergencymedicine-mhmedical-com.ezproxy.rowan.edu/content....