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SCC > Cardiac Support Devices > Flashcards

Cardiac Support Devices Flashcards

1
Q

What are some examples of cardiac support devices;

A

Intra-aortic balloon pump (IABP)
ECMO
Short-term ventricular assist devices
Permanent LVAD (L-ventricular assist devices)
TAH (total artificial heart)

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2
Q

This cardiac support devices consists of a flexible catheter with a distal cylindrical balloon that inflates and deflates in the descending thoracic aorta;

A

IABP

(Provides temporary hemodynamic support to pts in cardiogenic shock; typically after MI)

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3
Q

How does an IABP work?

A

IABP catheter has two lumens; one for transducing arterial pressure, one to deliver helium to balloon system

Inflation of balloon occurs during diastole (right after aortic valve closes)

Deflation of balloon occurs right before aortic valve opens and ventricular ejection

Cycles of inflation/deflation controlled by an external pump; usually synced to patient’s cardiac cycle as detected on arterial transducer or EKG

IABP augments cardiac cycle in 1;1 ratio or 1:2 ratio (every other beat)

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4
Q

How is an IABP placed?

A

Commonly via femoral approach

Floated to descending thoracic aorta; tip should be 1-2 at take-off of L-subclavian artery

Positioning/placement done under fluoro or TEE

Can be confirmed by chest X-ray showing tip 1-2 below aortic arch (between 2nd/3rd rib spaces)

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5
Q

Common reasons for IABP placement?

A

MI

Cardiogenic shock

Hemodynamic support around time of cardiac cath

Help with weaning from cardiopulmonary bypass

Pre-op support for high risk cardiac surgery

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6
Q

Clinical evidence shows IABP use limited to what?

A

Cardiogenic shock

MI without shock

High-risk PCI

Cardiac surgery

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7
Q

What are some physiological effects of the IABP?

A

Effects due to the inflation/deflation of the balloon in the aorta and displacement of blood in the aorta

Balloon inflation during diastole—-> helps diastolic pressure and root pressure

Balloon deflation right before LV ejection—> decreases afterload, LV wall stress, LV systolic work, myocardial oxygen demand, increase SV, CO

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8
Q

What’s an integral part of the IABP functioning properly?

A

Accurate timing

Early IABP inflation—> increases LV systolic stress, and LV afterload, thus decreasing SV

Late IABP deflation—-> increases afterload during systole

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9
Q

Absolute contraindications to IABP?

A

Significant aortic regurgitation

Aortic dissection—> can blow up balloon in false lumen making dissection worse

Aortic aneurysms

Other aortic pathology

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10
Q

MC complications of IABPs?

A

Bleeding

Vascular injury

Limb ischemia

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11
Q

Is there a limit to duration of IABP therapy?

A

No limit

But risks of complications increases with duration;

Independent risk factors for complications after IABP therapy; female sex, DM, PVD

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12
Q

What is counter-pulsation with the IABP?

A

When the heart contracts during systole—> the balloon deflates

When the heart relaxes during diastole—> balloon contracts

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13
Q

Benefits of IABP during inflation (diastole)?

A

Displaced blood from aorta, more blood goes retrograde to perfume the coronaries, also get an increase in SBP

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14
Q

What are some short term ventricular assist devices?

A

Impella + Tandemheart —-> percutaneously placed

Centrimag—> surgically placed

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15
Q

How do short-term short term ventricular assist devices like the Impella work?

A

They are continuous flow axial pumps

In the catheter there is a pump which revolves at high speeds to draw blood into the catheter and pump it forward

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16
Q

How does the Impella work?

A

Short term ventricular assist device

Impelle 2.0, 5.0, CP, and LD support LV function by taking blood from LV and pumping it out towards the aorta

The inflow part of the catheter is in the ventricle and the outflow part is in the aorta

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17
Q

How is the Impella LD (short term ventricular assist device) implanted?

A

Sternotomy or thoracotomy to place the device into the aorta and across the aortic valve

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18
Q

What is special about the Impella RP?

A

Used to assist RV function

Inflow part inserted into IVC and outflow part is in pulmonary artery

Can be placed percutaneously via common femoral vein

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19
Q

What are some uses of the Impella LVADs?

A

Cardiogenic shock

Decompensated heart failure

Bridge to cardiac tx

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20
Q

Benefits of Short-term ventricular assist devices like the Impella?

A

Augment forward flow in ascending aorta; increase CO

This increases coronary perfusion an end-organ perfusion

They also draw blood directly off the LV, off-loading the LV, thus reducing LV end-diastolic volume, thus reducing myocardial wall tension, myocardial work and oxygen demand

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21
Q

Benefits of Impalla RV device?

A

Increases Cardiac index ( CO/surface body area)

Decreases central venous pressure

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22
Q

Common complications of Impella devices?

A

Bleeding
Hemolysis
Vascular injury
Limb ischemia

23
Q

Benefit of Impella RP compared to other Impellas?

A

Impella RP can be used up to 14 days for acute right heart failure or decompensation after LVAD placement

Other Impella devices usually in for <6 hrs for temporary circulatory support

24
Q

What are some contraindications to placement of short-term ventricular assist devices?

A

Valvular or vascular pathology

25
Q

Continuous flow ventricular assist device that directs blood from left atrium to the systemic circulation;

A

Tandem-heart (short-term ventricular assist device)

26
Q

How does Tandem-Heart work?

A

Direct blood from left atrium to systemic circulation

Inflow cannula inserted via femoral vein into right atrium; then trans-septal puncture performed and cannula placed in left atrium

Blood from left atrium then pumped out into systemic circulation via femoral artery

27
Q

Complications from Tandemheart?

A

Bleeding, vascular injury, limb ischemia

Cannula migration, thromboembolism

Tamponade from septal puncture

Atrial-septal defect from residual hole after removal

28
Q

What is the centrimag?

A

Surgically placed, short-term, ventricular assist device that can be used for LV, RV and bi-ventricular support

Can generate up to 10 L/min of blood flow

29
Q

Where do we place the cannulas for Centrimag LV v RV support?

A

LV support; inflow is placed in LA and outflow is placed in ascending aorta

RV support; inflow is placed in RA and outflow is placed in pulmonary artery

30
Q

How long can the Centrimag be used for?

A

Up to 6 hrs for LV support

Up to 30 days for RV support

31
Q

What are two examples of continuous flow LVADs?

A

HeartWare
HeartMate II

32
Q

WHen do we use continuous flow LVADs?

A

End-stage heart failure pts awaiting heart tx

End stage heart failure pts who are not candidates for tx

End stage heart failure pts whose candidacy for tx has not been determined yet

33
Q

REMATCH trial?

A

demonstrated superiority of LVADs over medical therapy for treatment of end-stage heart failure

34
Q
A

Continuous flow LVAD; HeartMate II and Heart Ware

Inflow cannula is placed at the ventricular apex, outflow cannula is placed by aorta

HeartWare—> pump is implanted directly on heart apex

HeartMate—> pump is implanted subdiaphragamatically

35
Q

Flow pulsatility in continuous LVAD devices measures what?

A

Representative of the native ventricular function

36
Q

Contraindications to continuous LVADs?

A

Active malignancy

Advanced hepatic dysfunction

Severe obstructive pulmonary dx

Significant renal dysfunction

Systemic illness that limits life expectancy beyond 2 yrs

37
Q

How does aortic regurgitation affect continuous LVADs?

A

Creates a loop where the blood from aorta is regurgitating back into ventricle and pumped out of the LVAD in a continuous cycle

38
Q

WHy is RV function measured and important before placement of LVAD?

A

The increased CO may not be able to be accommodated by the RV

39
Q

Common complications of continuous LVADs?

A

Bleeding

Thrombo-embolism

Stroke

40
Q

What is a totally artificial heart?

A

Pts native valves and ventricles are removed and replaced by a pneumatically powered artificial heart

41
Q

How does a totally artificial heart work?

A

Two mechanical ventricles have two valves, each connected to aorta and pulmonary artery

42
Q

Indications for total artificial heart?

A

Pts with end-stage biventricular failure as a bridge to cardiac transplant

Also been used in pts with congenital heart dx, massive LV thrombus, large VSDs

43
Q

Risks with the total artificial heart?

A

No contraindications to valvular dysfunction; since all valves are replaced

Bleeding due to systemic anticoagulation, hemolysis and chronic anemia due to mechanical valves, oliguric renal failure, thromboembolism, stroke, infections

44
Q

What is VV ECMO?

A

Used for respiratory support

Blood is drained from venous system, to the pump, and oxygenator, and returned to the same venous system

***does not support cardiac output

45
Q

When do we use VV ECMO?

A

Indicated for hypercapnia or hypoxemia in setting of preserved CO

Cannulas are commonly placed in the IJ, femoral veins, or both

46
Q

Uses of VV ECMO?

A

Protect the lung to facilitate recovery while optimizing oxygenation and ventilation

Used in; ARDS, lung injury after drowning, end stage pulm dx as bridge to transplant

47
Q

What is AV ECMO?

A

Pumpless extracorporeal lung assist

Pt’s arterial-venous pressure gradient is driving force for flow

Blood flows from arterial femoral cannulation to gas exchange device and then back to venous circulation vie femoral venous cannula

This technique requires increased cardiac work; great for CO2 removal

48
Q

What’s a problem sometimes with multi-site VV ECMO?

A

Can get re-circulation of blood from one cannula, oxygenator and back into the other cannula without entering the heart

To combat this, a dual lumen, single stick catheter has been used; Avalon Elite dual lumen catheter

49
Q

What’s the advantage of single stick dual lumen VV ECMO catheters?

A

Avoids re-circulation phenomenon

Avoids access of femoral vessels and fear of limb ischemia

IJ usually used, more mobile for pt and nursing staff

50
Q

What is VA ECMO?

A

Veno-arterial ECMO; blood is drained from venous system and returned to the arterial circulation

51
Q

When do we use VA ECMO?

A

Indicated for cardia failure

Indicated for respiratory failure with hemodynamic instability or right heart failure

52
Q

What are some benefits of VA ECMO?

A

Decreases cardiac work, reduces ventricular wall tension, reduces myocardial oxygen consumption

Goal is to allow for myocardial recovery by reducing myocardial work

Reduces the native cardiac work

53
Q

ECMO and CPR?

A

Has been used to provide cardiopulmonary support during cardiac arrest vs conventional CPR

54
Q

Contraindications to ECMO;

A

Can’t obtain vascular access for cannulation

Severe irreversible multi-organ failure

Prolonged CPR without tissue perfusion

Unrecoverable cardiac function in pts not candidates for transplant

SCC (9 decks)

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