Artificial Heart

B. MeynsCardiale Heelkunde

UZ GasthuisbergLeuven

• Het klinisch probleem - Chronisch hart falen• Huidige status van ‘Ventricular Assist Devices’• Onderzoek en ontwikkeling

1. Het Klinisch ProbleemHartfalen

Schatting prevalentie Westerse wereldN

umbe

r of

Pat

ient

s (m

illio

ns)

NYHA Disease Severity Class

I II III IV Shock0

1

2

3

4

5

3.79m 3.62m3.11m

0.79m0.40mCRT 300,000

LVADS3,000

No Symptoms on Exertion

Symptomson Exertion Symptoms at Rest

IIIb early

Chronisch Hartfalen

• Oorzaken– Ischemisch lijden– Gedilateerde cardiomyopathie– Myocarditis– …

• Behandeling– Medicamenteuze ondersteuning– Resynchronisatie (pace-maker)– Transplantatie = Meest efficiënt

01/01/10

KUL patient survival

0102030405060708090

100

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

years

%

91 8673

52

the expert help of H. Ector, MD, PhD is gratefully acknowledged

NUMBER OF HEART TRANSPLANTS REPORTED BY YEAR

0

500

1000

1500

2000

2500

3000

3500

4000

4500

Num

ber o

f Tra

nspl

ants

OtherEuropeNorth America

ISHLT 200901/01/10

heart transplantation in Belgium

2 8 419

37

8093

127

108

154

124130115

98111116

96 9184 8180

877169697074

67

'82 '84 '86 '88 '90 '92 '94 '96 '98 '00 '02 '04 '06 '081 3 4 5 6 7 N active centers

01/01/10

- 44%

2. Huidige status van Ventricular Assist Devices

Het kunsthart voor hartchirurgie

Hartpompen

• Verplaatsingspompen– Slag volume– Kleppen

• Rotatie pompen– Centrifugaal– Axiaal– Diagonaal

1. Korte termijn (1week)centrifugaal pomp

ECMOHemopomp - Impella

Abiomed

2. Middenlange termijn (3 maanden)Medos

ThoratecBerlin Heart

3. Lange termijn (>3 maanden)Heartmate

Incor

PostcardiotomiePost -infarct

Plotse shock

Chronisch hartfalen

HartpompenIndicatie

Voorbeeld korte termijn pompImpella

Differential pressure sensor P aorta

P ventricle

Motor Cannula

0

1

2

3

4

5

6

0 30 60 90 120 150 180

differential pressure [mmHg]; PAorta-PVentrikel

flow

[l/M

in]

P1 P2 P3 P4 P5 P6 P7 P8 P9

ImpellaLP2.5

• Ease of Placement • 2.5 L/min• 12 Fr vascular access

Gebruik korte termijn pomp

• Therapie bij hartfalen na acute problemen • Hartrecuperatie is nog mogelijk in de eerste

dagen• Afhankelijk van de indicatie kan in 30 – 50 %

de hartfunctie gerecupereerd worden

Voorbeeld medium term

Plotse shock‘Bridging to transplantation’

Thoratec

Berlin Heart Excor

-verschillende ventrikels-poly-urethaan kleppen en mechanische kleppen-Silicone cannules

-Minder thrombus thv kleppen

controle pannel

Lange termijn pompen

Novacor

3 Novacor Recipients ongoing >4y(Berlin Heart Center)

• Male, 40 y/o, DCMP • Implant 7 Jul 2000• Permanent support• Pump exchange 08/02• Now BTT

• Male, 50 y/o, DCMP • Implant 6 Jun 2000• Permanent support• Pump exchange 05/04

• Female, 55 y/o, DCMP • Acromegaly, tumor, HIT II• Implant 8 May 2000• Permanent support

First patient >6y

Patient from Verona, IT (courtesy G. Faggian)

• 56 y/o, Chronic HF (13 yr)• High TPG, severe COPD• Elective pump replacement (1487

days; bearing wear and inflow valve incompetence)

• Eligible for Transplant• Transplant after 2220 days (6.08 yr)

• Totally implantable left ventricular assist device system

• Blood pump and cannulae, implanted controller, compliance chamber, power transmitter, power pack, charger/supply

• Not available

Arrow LionHeart 2000

• Kleiner, minder invasief• Geen kleppen• Minder complicaties (minder thrombusvorming)

• Mechanische ‘bearings’• Magnetische ophanging

Evolutie naar rotatiepompen

Incor

Jarvik 2000®

• Voornamelijk rotatie pompen• Overleving belangrijk verbeterd

68% at 1 yearMiller et al. NEJM 2007

• Geaccepteerde therapie in transplant centra

• Belangrijkste nevenwerkingen– Bloeding– CVA door bloedklonters– Kabel poort infectie

Lange termijn pompen

01/01/09

05

1015202530354045

'88 '90 '92 '94 '96 '98 '00 '02 '04 '06 '08

%

Eerste klinische studies lopen

- Grote chirurgie- Complicaties- Geen terugbetaling- Implementatie ?

‘Destination therapy’ ???

KUL VADaantal patiënten

0

10

20

30

40

50

60

70

ECMO

VAD

3. OntwikkelingenOnderzoek

• Kleiner; minder invasief• Recuperatie eigen hartfunctie ?• Pump control - sensing• Transcutane energie• Totaal artificieel hart

3.1 Kleiner – minder invasiefPartial support – The concept

• Pace-maker pocket• Outflow to subclavian

artery• Inflow from left atrium

(thoracotomy)• Cable tunneled to

abdomen

The pump

• Outer diameter: 13.2 mm• Length: 49 mm• Priming volume: 1.9 ml• max. rot. speed: 28,000 rpm• max. flow rate: 4 L / min, 80mmHg• design point: 2.5 L/min• Power consumption: 6 - 9 W• Mechanical –hydrodynamic bearing

0

50

100

150

200

250

0 1 2 3 4flow [l/min]

p [m

mH

g]

2000022000240002600028000

Inflow cannula and batteries

1. Incision under clavicle2. Small right thoracotomy3. Two purse strings on LA4. Seldinger insertion cannula5. Tunneling cannula to pace-

maker pocket6. Suture graft to subclavian

artery7. Tunnel cable to abdomen

No ECC

Implantation procedure

PocketIncision

IntendedPump

Position

Thoracotomy

2nd ICS 4th ICS

OutflowGraft

Two purse strings on left atrium

Seldinger insertion inflow cannula

Suture graft to subclavian arteryConnect pump

Technical details

Impeller

Inflow cage

Magnetic coupling

Motor

Ball bearing Pump housing

Graft connector

Bearing configuration

Axial bearing: mechanical / magnetic

Radial bearing: magnetic / hydrodynamic

Prevention of clott formation

Secondary flow path Washout holes

Original Washout (OWR) Enlarged Washout (EWR) Heart Shaped (HSR)

Rotor Designs

1.Computational fluid dynamics

2. Particle Image Velocimetry (PIV)Experimental Setup

3. In-vivo testing (animals)

5252

Original Washout (OWR) Enlarged Washout (EWR) Heart Shaped (HSR)

Rotor Design - PIV

Flow-visualisation 10:1 24krpm 3.3L/min

• Rare clinical data of weaning (not reproduced)– - Berlin Heart Center– - Harefield protocol with ‘clenbuterol’

• Depends of underlying disease• Current research focuses on

– Effect of unloading on the heart function– Window of opportunity to treat with medication

3.2 Recuperatie van de hartfunctie

• 150 papers• Different changes during support• The heart does show reverse remodeling• No prove of better function• Pump allows interaction with other drugs

• Algorhytms for pump speed reduction basedon motor current.

• Opportunity

3.3 Sensors – Pump control

Abdominale kabel

Permanente kabel

3.4 Transcutane energie

• Oude droom• In ontwikkeling– technical challenge• Maximaal invasief• Momenteel alleen als bridge

3.5 Totaal artificieel hart

• Home monitoring anticoagulatie• VAD nurses • E-Health

– Automatische controle van pomp stroom verbruik– Automatische controle van patiënt parameters

Implementatie met minimale inzet van zorgverleners

3.6. Home management