Assisted Circulation
1. Advanced Mechanical Support
A. Indications
1) Post-cardiotomy cardiogenic shock
2) Post-MI cardiogenic shock
3) Post-transplant graft failure
4) High-risk PTCA support
5) Cardiopulmonary resuscitation (CPR)
6) Hypothermia rewarming
7) Alternative to transplantation(clinical trials)
2. Circulatory Support
A. Mechanical cardiac assist
1) Intra-aortic balloon pump (IABP)
2) Ventricular assist devices (VAD)
3) Cardiopulmonary support (CPS, ECMO)
B. Mechanical cardiac replacement
1) Total artificial hearts (TAH)
C. Others
1) Biologic cardiac assist- cardiomyoplasty
2) Ventricular remodeling
3) Pacing
3. Mechanical Circulatory Support- Characterization
A. Output hemodynamics
1) Pulsatile
2) Non-pulsatile
B. Drive mechanism
1) Pneumatic; electric (hydraulic, mechanical)
C. Configuration
1) TAH, BVAD, RVAD, LVAD
D. Status/availability
1) Approved for market, IDE trials, in development
4. Placement position
A. Orthotopic; heterotopic; extracorporeal
B. Paracorporal; transcutaneous
C. Implantability
1) Fully; partially; not at all
D. Application/ permanence
1) Temporary; bridge-to-transplant, cardiogenic shock; bridge-to-recovery
2) Permanent; alternative-to-transplantation
5. Device Selection for Bridge-to-Transplantation
| Criteria | LVAD | RVAD | BVAD | TAH |
|---|---|---|---|---|
| LV failure | ++ | -- | -- | + |
| RV failure | -- | ++ | -- | + |
| LV & BV failure | -- | -- | + | + |
| Unresectable trombus | -- | -- | -- | + |
| S/P mechanical valve | -- | -- | -- | + |
| AI (or PI) | -- | -- | -- | + |
| Irreparable intracardiac shunts | -- | -- | -- | + |
| Uncorrectable arrhythmias | ? | ? | + | + |
| Refractory ischemia, angina | -- | -- | -- | + |
| Transplant heart rejection | -- | -- | -- | + |
| Acute MI at cannula site | ? | ? | ? | + |
| Unresectable cardiac tumor | -- | -- | -- | ? |
6. Bridge-to-Transplant
A. Problems
B. Cardiovascular
1) Failure on non-supported ventricle
2) Arrhythmias
3) Cyanosis/shunting with PFO
4) Ischemia/angina
C. Systemic
1) Hemorrhage
2) End-organ failure
3) Infection
4) Infection
5) Immune sensitization
6) Compromised quality of life
D. Device related
1) Thromboemboli
2) Obstruction/compression
3) Improper orientation
4) Device infection
5) Device failure
6) Hemorrhage
7) Air entrianment/embolus
8) Hemolysis
E. Results
1) 65-75% successfully bridged (90+% possible)
2) 90+% of those transplanted are discharged
7. Mechanical Circulatory Support– Issues for the future
A. Technological improvements
1) Size, biocompatibility, control, reliability, power and durability
B. Clinical effectiveness
1) Longevity, quality of life, complications, recovery, expertise
C. Cost-effectiveness
1) Of technology and implementation
D. Societal and ethical concerns
1) Allocation of resources; patient populations
E. Permanent Implantation– future NEED
1) By the year 2010
a) Number or patients: 35,000- 70,000 per year for long-term support
b) Devices:10,000-20,000 TAH and 25,000-60,000 VAD
8. Total Artificial Heart
A. Results– Bridge-to-transplant
| TAH | Control | |||
| N | % | N | % | |
| Pateints | 27 | -- | 18 | -- |
| Transplanted | 25 | 93 | 8 | 44 |
| Discharged home | 28 | 89 | 7 | 39 |
| Neurologic-embolic | 9 | 33 | -- | -- |
B. Copeland et al
9. Summary
A. May be life saving in selected patients with end-stage heart disease
B. Need for this intervention is increasing with decreasing donor availability
C. May ultimately become an alternative to transplantation
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