Ventricular Assist Devices Flashcards
How many hospital admissions annually for CHF and most commonly diagnosed in patients aged?
1 million
65 and older
What percent of the American population have congestive heart failure?
2 percent
That’s 4.8 million Americans
How many new cases of CHF each year and what mortality?
400,000
50% 5 year mortality
End stage heart failure is defined as
Symptoms at rest despite maximal medical therapy
High risk with no symptoms
Stage A
Structural heart disease with no symptoms
Stage B
Structural disease, previous or current symptoms
Stage C
Refractory symptoms requiring special intervention
Stage D
The first successful LVAD implant occurred in
1966
What became the first device to achieve FDA approval for short term use in 1992?
Abiomed BVS 5000
The VAD is a mechanical circulatory device used to ______ replace the function of either the left or right ventricle depending on the underlying heart disease
Partially or completely
What are the elements of VAD?
Inflow - atria or ventricle
Outflow - aorta, pulmonary artery, femoral artery
The bridge to recovery is used when
Patients heart failure is temporary
VADs can be implanted for a few weeks or months
The bridge to transplantation is implanted to temporarily support a heart failure patient while
Waiting for a heart transplant
VAD is removed when a new heart is implanted
A heart failure patient who is not eligible for a heart transplant will use VAD as
Destination therapy
What might disqualify someone for a heart transplant?
Advanced age, smoking, cancer, other health reasons
First generation VADs emulated the heart by using a _____, alternately sucking blood from ____ then forced out into
Pulsation action
Left ventricle
Aorta
Second generation VADs are ______ flow pumps with greater simplicity resulting in smaller size and reliability
Continuous flow
They are centrifugal pumps or axial flow impeller driven pumps
What is a side effect of a second generation pump?
The user will not have a pulse or the pulse intensity is greatly reduced
Example of first generation VAD?
HeartMate IP LVAS
Examples of second generation VADs?
Jarvik 2000 Pacemaker
Nimbus/Heartmate II
Micromed DeBakey
Third generation VADs suspend the impeller in the pump using _____. They remove the need for _____ and reduce the number of moving parts to
Hydrodynamic or electromagnetic suspension
Bearings, one
What does REMATCH stand for?
Randomized evaluation of mechanical assistance for the treatment of congestive heart failure
According to REMATCH, how did patients receiving HeartMate XVE compare with patients only receiving optimal medical management?
81% improvement in two year survival
What are the two major complications of VAD implantation?
Infection
Mechanical failure
Did REMATCH show that LVAD assist had better results of transplant compared with patients without LVAD?
Yes
The tandem Heart pVAD is a ______ centrifugal pump driven by a three phase motor capable of delivering up to
Extracorporeal
5 L/min
The Tandem Heart pVAD withdraws blood from the left atrium via _____ and returns it to
Transseptal cannula placement
Femoral artery
The goals of the Tandem Heart pVAD are to reduce _____ and ______. Increase
Left ventricular workload, myocardial O2 demand
Cardiac output, mean arterial pressure
What is an impeller? This is a component is which LVADs?
Motor used to increase the pressure and flow of a fluid.
Second and third generation
The HeartMate II can generate flows up to ___ and pressures up to
10 L/min
100 mmHg
Key clinical considerations for noncardiac surgery?
What chambers are being supported. Does the patient have LVAD, RVAD, BIVAD, or TAH?
Does the patient have pulsatile or no pulsatile pump?
What type of procedure?
What other questions should be considered when asking if a patient has a first or second generation pump?
Anticoagulation status
Determination of flow through pump
Electrocautery interference
Intravenous access
Four aspects have to be considered in the management of patients with LVADs presenting for non cardiac surgery
LVAD specialists
Power supply and electromagnetic interference
Hemodynamics
Anticoagulation
Why should a bipolar cautery be used when possible with LVADs?
The device is prone to alteration by electromagnetic interference such as electrocautery or a defibrillator.
The grounding pad should be placed to facilitate current dispersion away from device.
LVADs have to be connected to the _______ once the patient reaches the OR
Mains supply
The pumping mechanism of the LVAD depends on both
Preload and after load
T or F. LVADs obey Starlings law respect to stroke volume.
False. They can only pump the delivered volume; inadequate filling leads to inadequate flow. CVP, PAC, or TEE is indicated for procedures that will alter intraday ulnar volume.
Which positions can decrease preload? Other factors?
Lateral decubitus
Reverse trendelenburg
Drug induced venodilation, dehydration, hemorrhage
Elevation in after load ____ LVAD output and promotes ____. This occurs even when the patient is
Reduces
Stasis of blood and increase thrombus formation
Anticoagulated
What is the primary aim in peri operative management of patients with LVAD?
Avoidance of hypertension
Attenuation of systemic responses to laryngoscopy and surgical stimulus
What can cause low LVAD output?
Increased PVR
Reduced RV output
What should be used with caution with LVAD?
Negative inotropic drugs - volatiles, beta blockers, calcium channel blockers
What would you use to treat low LVAD output with increase in CVP?
Positive inodilator - milrinone
Pulmonary vasodilator - inhaled nitric oxide
LVAD patients require long term _____. Should it be continued on the day of surgery in patients using LVAD?
Warfarin treatment concerted to heparin therapy before elective surgery.
No, heparin treatment should be discontinued
