9. VADs- Exam 2 Flashcards
1
Q
year?
Carrell and Lindbergh and Demikhov
-Experimented with mechanical support in animal models
A
1930s
2
Q
Year?
Gibbon
-1st use of CPB
-Inability to wean fueled interest in prolonged mechanical support in order to promote myocardial recovery
A
1953
3
Q
year?
Spencer, et al.
-Reported using a roller pump to support a patient to recovery
-Roller pumps aren’t good VADS
A
1963
4
Q
why are roller pumps not good VADs
A
Tethering
Blood trauma
Adjust pump speeds due to changes in heart pressures
5
Q
year?
DeBakey
-1st successful clinical application of a true VAD
-Pneumatically driven diaphragm pump
-Paracorporeal= LA to Axillary Artery
-Supported for 10 days, weaned and discharged
A
1966
6
Q
year?
Klaus, et al.
-Introduced the concept of atrial counter pulsation
–Rapid systolic unloading of the ventricle with diastolic augmentation
A
1960s
7
Q
what did the introduction of atrial counter pulsation by Klaus in the 1960s lead to
A
Lead to the development of the balloon pump which was developed in 1963 and applied clinically in 1967
8
Q
year?
Total artificial heart was used in a dog model
-Supported for 90 min
A
1958
9
Q
year?
Reporting survival up to 24 hours with TAH
A
1962
10
Q
year?
Cooley
-1st used a TAH to temporarily support a patient to transplant
-Implanted the “Liotta Heart” which was a pneumatic device
-Supported the patient for 64 hours
A
1969
11
Q
who was the first in the world to implant a permanent TAH on 12/2/1982.
A
University of Utah investigators
12
Q
for the 1st implanted TAH by the university of utah: what was the name of the device? what doctor performed the procedure? name of the patient and their condition? how long did it support the patient?
A
- Jarvik 7 TAH
- performed by Dr. William DeVries
- Implanted into Dr. Barney Clark, 61 yo dentist with end stage idiopathic dilated cardiomyopathy. Died of complications from aspiration pneumonia, Renal failure, colitis with septicemia.
- Was supported for 112 days.
13
Q
how many patients received permanent TAH under FDA trial and what was the Longest survival
A
5 patients
620 days
14
Q
who did the 1st planned TAH implant as a Bridge to Transplant (BTT)? year?
A
1985 – Copeland at the University of Arizona
15
Q
what happened to the Syncardia, Cardiowest TAH from Tucson, AZ?
A
Device implanted in Tucson had issues with the manufacturer, so the FDA withdrew the FDA exemption for implantation
16
Q
after the FDA withdrew the FDA exemption for implantation of the Syncardia, Cardiowest TAH, what happened to it
A
Drs. Olsen and Copeland revived the model
Modified and renamed – Cardiowest C70
Received FDA Approval as a BTT in 2004
17
Q
year? Norman -Device used for 5 days of support -Intracorporeal pneumatic device -Patient died of multi-organ system failure s/p transplant
A
1978
18
Q
when did Transplantation became a widely applied therapy.
A
early 1980s
19
Q
in the earlt 1980s when Transplantation became a widely applied therapy–how many patients died on the list
A
30%
20
Q
year?
NIH sent out request for proposals
-To develop an “implantable, integrated, electrically powered left heart assist system” that could be used on a long term basis and allow extensive patient mobility
A
1980
21
Q
year?
Stanford University
-Oyer and Colleagues – Implanted the Novacor LVAD
-1st successful transplant s/p BTT with LVAD
A
9/1984
22
Q
who followed Stanford University’s 1st successful transplant s/p BTT with LVAD
A
Followed by Hill and colleagues who implanted a Pearce-Donachey pneumatic LVAD
23
Q
year? Frazier and colleagues -1st to report successful BTT with Thoratec Heartmate IP VAD -Implantable pneumatic -Restored near normal hemodynamics
A
1992
24
Q
what were the limitations to frazier and colleagues BTT with Thoratec Heartmate IP VAD
A
- Devices dependent on large consoles for power and controller function
- Patients confined to hospital until transplantation despite being fully ambulatory
25
year?
Kormos at University of Pittsburg
-Developed a program to transfer VAD patients to a monitored outpatient setting until transplantation
1990
26
year?
Frazier at Texas Heart Institute
-First to use an untethered vented electric LVAD for long term support
1991
27
describe the untethered vented electric LVAD Frazier did at Texas Heart Institute in 1991
Battery operated Heartmate VE
500 days of support
Patient died of embolic cerebral vascular accident
28
year?
| FDA sponsored several multi-institution trials of assist devices as bridge to transplant and bridge to recovery
1990s
29
year?
| Heartmate LVAD was the first FDA approved implantable device for bridge to transplant
1994
30
what are some
- Blood versus Foreign surface
- Moving parts
- Changes to patients anticoagulation and immune system over time in response to the mechanical pump
- Pharmacologic modifications
31
why is Blood versus Foreign surface a Biological Barriers to VAD design
Blood contact surface cannot harm the patient
| Minimum generation of blood clots
32
why is Changes to patients anticoagulation and immune system over time in response to the mechanical pump a Biological Barriers to VAD design
Coagulopathy immediately after implantation b/c of CPB
Period of hypercoagulability
Returning to baseline
33
why is Pharmacologic modifications a Biological Barriers to VAD design
(Heparin, Coumadin, ASA)
| Need to anticoagulate on some level
34
Indications for VAD:
| Bridge to Transplant=
Worsening hemodynamics despite high level of IV inotropic support and/or vasodilator therapy or refractor arrhythmias
35
Indications for VAD:
| Destination Therapy=
Patients who are not transplant candidates. Have an EF less than 25% and NYHA Class IV symptoms despite optimal therapy
36
name 5 contraindications for VADs
| there are 14 on slide 17
- Neurological deficits impairing the ability to manage device
- Coexisting terminal condition
- Abdominal aortic aneurysm (greater than 5 cm)
- Active infection
- Inability to tolerate anticoagulation
37
name 5 design musts
| there are more on slide 18
- Structurally stable in a corrosive saline environment
- Operate continuously w/o regular maintenance for years.
- Cannot fail under increased stress conditions
- Reduce power requirements to save battery life
- Must be efficient – reduce heat waste.
38
Positive Displacement VS Rotary Pump:
| Flow and Pressure
Positive Displacement: Change volume in the chamber
| Rotary: Rotating Impeller
39
Positive Displacement VS Rotary Pump:
| Source of Energy
Positive Displacement: Air pressure/ Electricity
| Rotary: Electricity
40
Positive Displacement VS Rotary Pump:
| Size
Rotary is smaller with a smaller cannula
41
Positive Displacement VS Rotary Pump:
| Prime Volume
Positive Displacement: Large Prime Volume
| Rotary: Smaller Prime Volume
42
Positive Displacement VS Rotary Pump:
| Flow Ranges
Both plagued with thrombosis with decreased flow and hemolysis with increased flow
43
Positive Displacement VS Rotary Pump:
| Afterload
Positive Displacement: Unaffected by changes in afterload
| Rotary: Flow drops with increased SVR
44
Positive Displacement VS Rotary Pump:
| Preload
Positive Displacement: Passive filling, output follows venous return
Rotary: Flow increases with increased VR, but no active suction applied
45
how do Positive Displacement pumps work
- Propels fluid by changing the internal volume of a pumping chamber. (Compression of a sac/membrane_
- Provides pulsatile flow
- Requires 1 way valves to produce forward flow
46
Positive Displacement pumps: flow
5-10 liters per minute
47
Positive Displacement pumps: mean BP
100-150 mmHg
48
Positive Displacement pumps: rate (bpm)
<120 bpm
49
Positive Displacement pumps: Mean filling pressure
appx 20mmHg
50
Thoratec PVAD/IVAD has been approved by the FDA for a BTT device since what year
1995
51
Thoratec PVAD/IVAD provides support for what
Provides support for the right, left or both ventricles
52
what % of of LVADs will need an RVAD
10%
53
a BiVAD is common after what?
```
transplant failure
postpartum Cardiomyopathy
Acute MI
Myocarditis
Used least with idiopathic CM and Ischemic CM
```
54
According to the Thoratec Registry, __% received BiVAD support with hybrid RVAD and LVAD or Thoratec BiVAD
25%
55
BiVAD use has increased __% since 2000
18%
56
Preop risk factors for Right Heart Failure include?
- Hemodynamics – Low CI with inc. RA pressure not necessarily an indicator of Rt. Heart failure. (May improve when LV is unloaded with LVAD)
- Ability of RV to generate pressure
- Low pulse pressure with high CVP – indicator of BiVAD
57
Indicators of BiVAD include what 6 things
1. Early insertion of LVAD before significant major organ dysfunction
2. Higher pre-op bilirubin
3. Higher pre-op creatinine
4. Emergent Implant
5. Intraop Bleeding
6. Greater transfusion requirements increases pulmonary vascular resistance and promotes the development of right heart failure.
58
why is Early insertion of LVAD before significant major organ dysfunction an indicator for a BiVAD
Less likely to need RVAD too
59
why is Higher pre-op creatinine an indicator for a BiVAD
Normalize w/in 2-3 weeks after implant of VAD
60
why is Post op bleeding is common for BiVAD patients
Related to the severity of hepatic failure
61
Thoratec PVAD/IVAD: internal mechanics
- 65 mL Stroke volume pump chamber
- Made of Thoralon Polyurethane
- 2 mechanical valves
- Alternate positive and negative air pressure by console/ Portable driver
62
Thoratec PVAD/IVAD: bpm and lpm
Beats 40-110 bpm
| Flow is 1.3-7.2 Lpm
63
Thoratec PVAD/IVAD: is placed where?
- Placed in the anterior abdominal wall with cannulas crossing into the chest wall to connect the VAD to the heart and great vessels.
- External location is suitable for use in smaller patients
- BSA >0.73m2
64
what are the 6 Pump considerations for Implant: Thoratec PVAD/IVAD
1. Ideally use bicaval cannulation
2. Normothermic
3. 0w/o cardioplegia or XC
4. LV Vented
5. De-aired via LV Apex cannula before connecting to the VAD
6. Ultrafiltrate to keep hematocrit greater than 30% (in case clotting factors are needed to assist coagulation)
65
describe the Anticoagulation for Thoratec PVAD/IVAD
Chronic Warfarin Anticoagulation: INR= 2.5-3.5
- Starts with heparin – PTT 1.5x baseline until GI function is stable and show low bleeding risk (10-14 days)
- Switch to warfarin and ASA
66
Worldwide survival from implant to transplant/ recovery:
RVADs %
BIVADs %
LVADs %
31. 2% of RVADs
56. 6% of BIVADs
64. 8% of LVADs
67
why can the PVAD be used in pediatrics
due to being paracorporeal
68
how many peds patients as of 1/2005 have received a PVAD
150
69
what are the adverse events to the PVAD
Thromboembolism
| Hemorrhage (more common than in adults)
70
what is the % survival rate for PVADs
68.4%
71
Intracorporeal VAD (or Implantable VAD)=
Used when longer term support is anticipated
Approved in 2004 by the FDA as a BTT or BTR
BSA >1.3m2 b/c of intracorporeal position
72
how are IVADs different from PVADs
```
Polished Titanium Body – makes it implantable
Reduced weight
339gms vs. 417 gms
Narrower Percutaneous leads
9mm vs. 20mm
```
73
the Heartmate XVE has been placed in how many patients world wide
5000
74
benefits of the Heartmate XVE
- Textured inner surface
- Circulatory assistance without anticoagulation except an antiplatelet agent
- Promotes pseudointimal layer= Limits thrombogenesis
75
cons of the Heartmate XVE
Immunologically active
| -Limit transplant candidacy due to increase in immunologic reactivity.
76
describe the mechanics of the Heartmate XVE
- Positive displacement pump
- Made of titanium with a polyurethane diaphragm and a pusher plate actuator (which is responsible for producing mechanical energy).
- Powered pneumatically: 9kg driver console, batteries (4-7hours of use)
77
where is the Heartmate XVE cannulated
1. Cannulate LV Apex (apical cannula)
- Dacron conduit with 25mm porcine valve
2. Cannulate ascending aorta
- 20mm Dacron outflow graft with porcine valve
78
Heartmate XVE: stroke volume
83 ml
79
Heartmate XVE: fixed vs auto mode
1. Auto - SV maintained at 97% full. Flow – 4-10 Lpm
| 2. Fixed – stroke volume depends upon filling. Rate is adjusted manually to keep stroke volume between 70-80mL
80
describe the pseudointima promoted by the Heartmate XVE
- Thin layer of biologic matrix that resists thrombogenesis
- Composed of cellular elements, collagen, and cells derived from circulating progenitor cells.
- Immunologically active microenvironment
- Heightened susceptibility to opportunistic infections
81
describe the implantation of Heartmate XVE (6)
- Dacron grafts must be pre-clotted
- Placed intraperitoneal or in peritoneal pocket in left upper quadrant. Must go through diaphragm with cannulas
- AI, MS and PFOs must be corrected at implantation
- Requires CPB, No cardioplegia or cooling
- BSA: >1.5m2
- Anticoagulation – ASA only
82
when do the bearing wear out on the Heartmate XVE
18-24 months
83
with the Heartmate XVE, Vent filters are changed regularly and sent to Thoratec for evaluation. Why?
- Test for signs of motor dust
| - Excessive motor dust is an indication of bearing wear
84
Heartmate XVE: BTT Survival
| __% survive to transplant/ recovery. If they survive the first month, they have an __% chance of a successful outcome.
65%
| 85%
85
- DeBakey and Noon developed a small axial flow LVAD that went into clinical trials in ____
- Followed by Jarvik 2000 in ____
- Nimbus/ HMII axial flow pump in ____
1998
1999
2000
86
how do Rotary pumps work
Uses rotating impellers to propel blood forward
Supported with bearings
Powered by spinning shaft/ magnetic forces
87
describe the Micromed
- Mini electromagnetically actuated titanium pump with ball and cup bearings weighing less than 93 grams
- Has Elbow shaped inflow cannula, pump housing unit, dacro outflow, *ultrasonic flow probe encircling outflow graft*, flexible drive line to controller
88
describe the development of the Micromed by Debakey
- Collaboration between NASA engineers and Dr. DeBakey and Dr. George Noon
- Established in 6/1996 with NASA license
- Implanted in 1998 in Europe
89
what is used for anti-coagulation for the micromed
coumadin
90
what are some management issues of micromed
- Fibrin deposition on Impellar leading to thrombus formation=Could lead to pump stoppage or Back flow
- Treatment is TPA and Heparin
- Possible device change out
91
when was the Heartmate II developed? describe the collaboration
early 1990s
Collaboration between engineers at Nimbus, Inc and Univeristy of Pittsburg
Initially developed thru NIH grant
92
Heartmate II=
Axial flow device (2nd generation VAD)
| Reduced size/ weight compared to XVE
93
describe the internal mechanics of the heartmate II
- Electric Motor
- Rotor spins within magnetic field on inlet and outlet of bearings-Only moving part of pump
- Dacron grafts may require pre-clotting
94
with the heartmate II, Flow is an ESTIMATE and is not accurate under what floe
3 lpm
95
where is the heartmate II implanted
Implant is below the L. Costal Margin under the rectus abdominus muscle
Leave LV Apex to diaphragm to pump
96
when was the heartmate II approved as a Destination Therapy device.
1/20/2010
97
heartmate II 1 and 2 year survival %
Survival to 1 year was 68%
| Survival to 2 years was 58%
98
what the longest duration of use for the heartmate II
6+ years (patient still on device)
99
bsa range for the heartmate II
BSA: 1.14-3.16m2
100
heartmate II: ___% have either been transplanted, recovered or supported to 6 months
90%
101
when did the Randomized Evolution of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH) Trial start
1996
102
REAMATCH trial=
- Provided evidence for FDA to approve the device for Destination Therapy in 2002
- Medicare approved device for permanent implantation in 2003
- Set the stage for multiple clinical trials of other devices as permanent therapy for heart failure
103
VentrAssist=
3rd generation device (from Australia)
| device development stopped due to lack of company funds
104
Heartware HVAD=
Small continuous flow rotary pump with a centrifugal and non-contact bearing design
- First human implant – 2006
- Approved November 20, 2012
105
where is the heartware HVAD implanted
Placed within the pericardial cavity at the apex of the LV
| -No need for abdominal pocket
106
DuraHeart LVAS=
By Terumo Heart, Inc.: 2nd gen
| Continuous-flow rotary pump
107
DuraHeart LVAS flow rate and motor speed
Flow rates of 2-8lpm
| motor speeds of 1200-2400rpm
108
Levacor VAD=
By WorldHeart Corp.
| -Bearingless centrifugal pump with an impeller competely magnetically levitated
109
where is the Levacor VAD implanted
Implanted in small subcostal, pre-peritoneal space
110
Abiomed Impella 2.5/5.0=
Intracatheter VAD
Can pump 2.5/5.0 Lpm
Pulls blood from the LV tip to the aorta.
111
First completely self-contained replacement heart=
Abiomed Abiocor
112
VAD Capable of pumping 12 liters per minute=
Abiomed Abiocor
113
Tandem Heart=
10cc hydrodynamic centrifugal pump
- Integrated motor
- 21 pounds
- 1 hour backup battery
114
Tandem Heart flows
8LPM flow
Cannula dependent
-Tandem Heart transeptal cannula and 17fr arterial cannula = 5LPM
115
Syncardia TAH=
- After implant and stable, patient is moved to 1A , top of the list
- 6 moving parts – inflow and outflow valves, and the diaphragm
- All electronics outside the body
- Utilizes a pneumatic driver
116
syncardia TAH flows
9.5 liters per minute through both ventricles
117
Berlin Heart=
December 16, 2011 – FDA approved Berlin Heart (Excor Pediatric System)
