LVAD/RVAD/Heart Transplant Flashcards
What were the first generation LVADs?
HeartMate1, Thoratec PVAD, and Novacor N100; they were pulsatile
What is the difference between centrifugal and axial flow LVADs?
Axial flow = blood enters one end of a rotor and is driven along the axia of the rotor to the outflow (higher shear stress and hemolysis); Centrifugal flow = blood enters at the central axis and is driven outward to the outflow pump (less shear stress)
Which LVAD works via axial flow?
HeartMate II
What are the 6 components of an LVAD?
Inflow cannula + pump + outflow cannula + percutaneous driveline + power supply + controller
What are absolute contraindications for an LVAD?
Unrepaired VSD/PFO/ASD + acute endocarditis + aortic dissection + AI >/= moderate + mechanical AV (increased risk of thrombus)
What considerations should you have with your anesthetics in a minimally invasive LVAD implantation?
Peripheral CPB + ventilation required while on CPB + one lung ventilation at times + TEE
What are pre-implantation red flag findings on TEE?
LV and interventricular septum findings (small LV size, thrombus, aneurysm, or VSD) + RV (dilation or decreased function) + LAA thrombus + PFO/ASD + valvular abnormalities (prosthetic valves, >mild AI, mod/sev MS, mod/sev TR, > mild TS, > mild PS, mod/sev PR) + acute aortic pathology + mobile mass lesion
What are post-implantation red flag findings on TEE?
Septal shifts + size of LV (large or small) + RV dysfunction + > mild AI + mod/sev TR + turbulent outflow
What is the pulse index?
A unitless value that averages the number of LV contractions (flow pulses) over a 15 sec interval
What are you concerned about if you see an alarm for high flow? Low flow?
High flow = vasodilatory state (i.e. sepsis -> consider vasopressor); Low flow = suction event (i.e. hypovolemia)
What are you concerned about if you see an alarm for high power? Low power?
High power = pump thrombosis (tx = anticoagulation or pump exchange); Low power = Pump failure/ disconnection
What are you concerned about if you see an alarm for low pulse index?
Suction event
How much can an Impella RP flow?
Up to 5L/min of axial flow
Where does an Impella RP sit?
Usually starts at the femoral vein; the silver ball outlet should be 2-4cm from the pulmonic valve while the inlet should be at the level of the IVC
What is the ProtekDuo?
Dual-lumen cannula where inflow sits in SVC/RA junction and the second lumen (outflow) sits in the PA; usually accessed via the RIJ and can give 4-5 L/min of centrifugal flow; you can also ambulate unlike the Impella RP
What is the Spectrum Medical Dual Lumen Cannula?
Similar to the ProtekDuo except it has two drainage sites (one in the RA and another in the RV); the outflow outlet remains distal to the PA
What is the CentriMag RVAD?
Surgically implanted RVAD with the inflow cannula in the RA (via SVC or IVC) and the outflow cannula in the PA; centrifugal pump that can provide up to 7 L/min
Can you add an oxygenator to an Impella RP?
No
What makes a patient a Status 1 transplant candidate?
ECMO (up to 7 days) + VAD + mechanical circulatory support with ventricular arrhythmias
What are contraindications for orthotopic heart transplantation?
Sever systemic illness + pulmonary HTN (PVR > 3 Wood units) + psychosocial criteria + acute or recent malignancy + multisystem disease with organ dysfunction + severe symptomatic cerebrovascular disease
What is the biatrial technique for OHT?
The posterior wall of the RA with connections to the IVC/SVC remain attached; will see two p waves
What is the bicaval technique for OHT?
The RA is explanted without the IVC/SVC connections so you need to reconnect the IVC/SVC as well as the LA and the great vessels
What is the total OHT technique?
The entire heart is explanted leaving behind two LA cuffs (pulmonary veins); need to make SVC/IVC, great vessels, and two LA cuff anastamoses
How is ex-vivo heart perfusion (EVHP) done?
The ends of the IVC and SVC are ligated and the donor aorta and PA are cannulated; maintenance solution is infused
What is the goal total ischemic time for OHT?
<300 minutes (but ideally <240 minutes)
What is primary graft dysfunction?
Diagnosed within 24 hours of transplant; can be left (PGD-LV) or right (PGD-RV); increased 30-day and 1-year mortality
What is secondary graft dysfunction?
Hyperacute rejection with known pulmonary HTN or surgical complication
What are donor specific risk factors for primary graft dysfunction?
Age, female, cause of death, trauama, cardiac dysfunction, inotropic support
What are recipient specific risk factors for primary graft dysfunction?
Age, elevated PVR, Inotropic support, congenital heart disease, preop amio use, redo sternotomy, allosensitization
What are procedural specific risk factors for primary graft dysfunction?
Ischemic time, donor-recipient sex and weight mismatch, increased transfusions, cardioplegic solution, experience of team, redo heart transplant
How does brain stem death in the donor affect the potential for primary graft dysfunction?
Increased ICP -> adrenergic response -> Pulm/systemic HTN -> increased afterload and O2 demand; Loss of spinal cord SNS -> decreased preload/afterload -> severe vasodilation -> myocardial NE release -> increased O2 demand
What is the major indicator for what level of primary graft dysfunction we have after lung transplantation?
The PaO2/FiO2 ratio; if <200, grade 3
What is the most common valvular dysfunction after OHT?
Tricuspid regurgitation (possibly from pulmonary HTN, annular dilation from RV dilation, alteration of RA morphology due to surgery, or papillary dysfunction)
Why is the bicaval technique for OHT better than the biatrial technique?
The bicaval technique reduces the incidence of late RA dilation, need for temporary pacing, SVT arrhythmias, and TR
