TRANSLATIONAL SCIENCE What is it? How does it relate to the practise of perfusion?

The scientist’s perspective

Clive Landis

Edmund Cohen Laboratory for Vascular Research University of the West Indies, Barbados

Disclosures

Barbados Diabetes Foundation Bayer Healthcare British Heart Foundation Cave Shepherd Ltd. Cellplex Destiny Group of Companies Edmund Cohen Foundation Medicor International Point Care Technologies

Medical innovation that yields meaningful clinical benefit and advances the

national competitive edge

What is translational research?

Scientists Industry

Clinicians Government

1. rational interventions 2. biological feedback 3. real time information

What do you really need?

Contact of blood with the foreign surface of the bypass circuit activates:

Need for a more holistic view of blood activation

  Coagulation System   Cytokines and white cells   Fibrinolytic System   Platelets   Complement System   Hemolysis

“… activation of complement, coagulation, fibrinolytic, and kallikrein cascades, activation of neutrophils with degranulation and protease enzyme release, oxygen radical production, and the synthesis of various cytokines from mononuclear cells”

Butler J, Rocker GM, Westaby S. 1993. Inflammatory response to cardiopulmonary bypass. Ann. Thorac. Surg 55:552-9.

systemic factors

Is heparin coating a rational intervention?

1. rational interventions 2. biological feedback 3. real time information

What do you really need?

How adequate is tissue perfusion in your patient?

systemic factors organ injury local trigger + =

Landis, C. J Extracorpor Technol 2007;39:281 Landis, RC. Sem Cardiovasc Anesth 2009, in press Landis RC. Core Topics in Cardiac Anaesthesia, 2nd Ed. 2009 …

Platelet activation

Endothelial activation

Bradykinin

Leukocyteactivation

XII

intrinsic coagulation

Kallikrein

fibrinolysis

tPA

Plasmin C3

C5

IgM/IgG

classical complement

white cell adhesion

Oxidative stress

hemolysis/ RBC transf

systemic

local

Thrombin

organ injury

Platelet activation

Endothelial activation

Bradykinin

Leukocyteactivation

XII

intrinsic coagulation

Kallikrein

fibrinolysis

tPA

Plasmin C3

C5

IgM/IgG

classical complement

white cell adhesion

Oxidative stress

hemolysis/ RBC transf

systemic

local Inflammation, cytodestruction

Thrombin

Ritter LS et al. Stroke 2000;31:1153

Rat Model

Midline cerebral artery

Ischemia/Reperfusion

Pre-occlusion

ischemic reperfused

local trigger

Cognitive impairment is associated with perioperative ischemia and is more severe with greater ischemic load

1. rational interventions 2. biological feedback 3. real time information

What do you really need?

cerebral oxymetry

“Monitoring cerebral rSO2 in coronary artery bypass patients avoids profound cerebral oxygen

desaturation and is associated with significantly fewer incidences of organ dysfunction”

“How useful would it be to your discipline to receive real time information on multiple inflammatory cytokines?”

The value of cross cutting disciplines

(Private research foundation from the field of flow cytometry)

1. coagulation 2. flow cytometry 3. army 4. aviation 5. rheumatology ...

cross cutting disciplines …

systemic factors organ injury local trigger + =

Intervention: pharmacologic/ circuit modification approaches

Intervention: clinical management changes

long term strategy

short term

Landis, C. J Extracorpor Technol 2007;39:281 Landis, RC. Sem Cardiovasc Anesth 2009, in press Landis RC. Core Topics in Cardiac Anaesthesia, 2nd Ed. 2009 …

Imperial College London Betsy Evans Ken Taylor

Edmund Cohen Laboratory Andre Greenidge

Kim Quimby

ICEBP pharma writing group Rob Baker

Jeremiah Brown John Murkin

Donny Likosky

Consensus Statement writing group

Dartmouth Eric Toler

Bob Kramer

Joe Arrowsmith Filip de Somer

Wojciech Dobkowski Gregory Fisher Richard Jonas Michael Poullis David Stump Ed Verrier

“Every attempt should be applied to avoid hyperlactatemia during CPB, and the critical Do2 value of 260 to 270 ml/minute per m2 should be

considered whenever setting the pump flow and the maximum acceptable hemodilution degree”

Marco Ranucci, Barbara De Toffol, Giuseppe Isgrò, Federica Romitti, Daniela Conti and Maira Vicentini. Crit Care Med 2006;10:R167

Summary: leukocytes in organ injury

•  Inflammatory leukocytes extravasate into tissues and organs post CPB

•  Ischemia/reperfusion injury is a potent trigger for leukocyte extravasation

•  Extent of injury depends on leukocyte- and endothelial- activation

Scientists

Industry

Clinicians Government

ABNORMAL BLOOD FLOW HYPERCOAGULABILITY

ENDOTHELIAL INJURY

Virchow RR. Cellular Pathology. London, Churchill, 1860

vessel trauma/injury local trigger

Intact internal elastic lamina

Graft intima

Internal elastic lamina

disrupted

Elastin stain 200X 200X

Prior to pressure distention After pressure distention

Hand injection with standard syringe

CD31 immunohistochemistry

Intact endothelium

CD31 immunohistochemistry

Disrupted endothelium

Slide courtesy of: Rob Poston

Intraoperative Conduit Imaging

Slide courtesy of: Rob Poston

LA = 4.25

1 mm

Before

harvest

LA = 1.74 LA = 2.04 LA = 1.01

LA = 4.17 LA = 3.04

LA = 4.39 LA = 3.94 LA = 4.88

Before harvest

1 mm

LA = 4.58 LA = 3.92 LA = 4.22

Harmonic Scalpel

Electrocautery

Proximal Middle Distal

Slide courtesy of: Rob Poston

HAMMON JH, et al. CABG WITH SINGLE CLAMP IMPROVES NEUROPSYCHOLOGICAL OUTCOMES Ann Thorac Surg 2007;84:1174.

clamp

local trigger

aortic x-clamp: - multiple - excessive force

Immediate interventions to attenuate the systemic inflammatory approach:

Preventing local triggers

  Whole team approach   gentle handling & clamping of vessels   minimize tissue ischemia   cell saver/leukofiltration   temperature/emboli/rSO2 monitoring

Immediate interventions to attenuate the systemic inflammatory approach:

Preventing local triggers

  Whole team approach   gentle handling & clamping of vessels   minimize tissue ischemia   cell saver/leukofiltration   temperature/emboli/rSO2 monitoring

TITLE: An evidence-based review of pharmaceutical interventions to limit the systemic inflammatory response in cardiac surgery AUTHORS: Landis RC, *Brown JR, †Murkin JH, *Likosky DS, §Baker RA for the International Consortium for Evidence Based Perfusion AFFILIATION: Edmund Cohen Laboratory for Vascular Research, University of the West Indies, Barbados; *The Dartmouth Institute for Health Policy and Clinical Practice, Lebanon, NH, USA; †London Health Sciences Center, London, Ontario, Canada; §Flinders Medical Center, Adelaide, Australia. INTRODUCTION: We report here the first evidence-based review of pharmaceutical strategies to limit the systemic inflammatory response in adult coronary artery bypass grafting surgery.

Pharmaceutical suppression of

the evidence base

systemic factors

Landis, RC, Brown JR, Murkin JM, Likosky DS, Baker RA. Heart Surg Forum (2008);5:E308. Brown JR, Toler AWJ, Toler RE, Landis RC. J Extracorpor Technol (2009) - in press

Mesh search terms

Search 1: ((("thoracic surgery"[TIAB] NOT Medline[SB]) OR "thoracic surgery"[MeSH Terms] OR cardiac surgery[Text Word]) OR ((("cardiopulmonary bypass"[TIAB] NOT Medline[SB]) OR "cardiopulmonary bypass"[MeSH Terms] OR

("coronary artery bypass"[TIAB] NOT Medline[SB]) OR "coronary artery bypass"[MeSH Terms] OR"Heart-lung machine"[MeSH Terms]) OR ((("heart valves"[TIAB] NOT Medline[SB]) OR "heart valves"[MeSH Terms] OR valve[Text

Word]) OR valves[All Fields] OR valvular[All Fields]) AND ("surgery"[Subheading] OR "operative surgical procedures"[Text Word] OR "surgical procedures, operative"[MeSH Terms] OR "surgery"[MeSH Terms] OR surgery

[Text Word]))) AND (#19) Limits: Humans, Randomized Controlled Trial, English Search 2: (aprotinin OR dexamethasone OR steroids OR cortisol OR aspirin OR tranexamic acid OR aminocaproic

acid) AND ((Inflammation OR cytokines OR interleukin OR tnf OR (tumor necrosis factor) OR (leukocyte count) OR granulocytes OR immunoelectrophoresis OR monocytes OR (cell adhesion molecules) OR leukocyte OR aprotinin OR dexamethasone OR steroids OR cortisol OR aspirin OR tranexamic acid OR aminocaproic acid) AND (cardiac surgery OR ((("cardiopulmonary bypass"[TIAB] NOT Medline[SB]) OR "cardiopulmonary bypass"[MeSH Terms] OR ("coronary artery bypass"[TIAB] NOT Medline[SB]) OR "coronary artery bypass"[MeSH Terms]) OR (valve OR valves OR valvular)

AND and surgery))) AND ((Humans[Mesh]) AND (English[lang]) AND (Randomized Controlled Trial[ptyp])) Search 3: (("thoracic surgery"[TIAB] NOT Medline[SB]) OR "thoracic surgery"[MeSH Terms] OR cardiac surgery[Text

Word]) OR ((("cardiopulmonary bypass"[TIAB] NOT Medline[SB]) OR "cardiopulmonary bypass"[MeSH Terms] OR ("coronary artery bypass"[TIAB] NOT Medline[SB]) OR "coronary artery bypass"[MeSH Terms] OR"Heart-lung

machine"[MeSH Terms]) OR ((("heart valves"[TIAB] NOT Medline[SB]) OR "heart valves"[MeSH Terms] OR valve[Text Word]) OR valves[All Fields] OR valvular[All Fields]) AND ("surgery"[Subheading] OR "operative surgical

procedures"[Text Word] OR "surgical procedures, operative"[MeSH Terms] OR "surgery"[MeSH Terms] OR surgery[Text Word]))

Search 4: (("complement activation"[MeSH Terms] OR complement activation[Text Word]) OR ("complement system proteins"[MeSH Terms] OR complement system proteins[Text Word]) OR complement[Text Word]) OR

("kallikreins"[MeSH Terms] OR kallikrein[Text Word]) or (inflammatory[All Fields])

Systematic search of the literature … 1970 - 2008 randomised drug trials inflammatory response 439 papers

Exclusion criteria … pediatric off-pump, valve, other CT procedures

Inclusion criteria … adult CABG measure at least one inflammatory marker

64 papers

16 papers

Measure organ function to heart, lung, brain, kidney, gut

Systematic search of the literature … 1970 - 2008 randomised drug trials inflammatory response 439 papers

Exclusion criteria … pediatric off-pump, valve, other CT procedures

Inclusion criteria … adult CABG measure at least one inflammatory marker

64 papers No meta-analyses met inclusion criteria

16 papers

Measure organ function to heart, lung, brain, kidney, gut

Conclusions

The evidence base is poor

Most studies do not measure a single inflammatory marker

No meta-analyses

Only Methylprednisolone merited a Class IIa clinical recommendation based on multiple randomised trials

Conclusions

The evidence base is poor

Most studies do not measure a single inflammatory marker

No meta-analyses

Only Methylprednisolone merited a Class IIa clinical recommendation based on multiple randomised trials Reveals need to define criteria for carrying out

such studies in future

Pharmaceutical interventions are not a short term option

Any plausible pharmaceutical strategies in the long term?

long term pharmaceutical strategies

1. combinatorial approach

Platelet activation

Endothelial activation

Bradykinin

Leukocyteactivation

XII

intrinsic coagulation

Kallikrein

fibrinolysis

tPA

Plasmin C3

C5

IgM/IgG

classical complement

white cell adhesion

Oxidative stress

hemolysis/ RBC transf

systemic

local

Thrombin

organ injury

1. combinatorial strategy

2. thrombin receptor antagonists

long term pharmaceutical strategies

Fibrin

Fibrinogen

Hemostasis

Controlled thrombin generation

Hemostasis

Controlled thrombin generation

PAR1

Fibrin

Fibrinogen

Thrombin burst

new drug target ?

pl rich occlusive thrombus

Platelets – aggregation Endothelial cells – inflammation Neural cells - apoptosis

? ? ?

No increase in TIMI bleeding

(46% reduction in MACE)

TRA-PCI: Phase II

Becker RC, et al. Lancet 2009; 373:872.

1. combinatorial strategy

2. thrombin receptor antagonists

3. leukocyte adhesion antagonists

4. improved circuit coating

long term pharmaceutical strategies

systemic factors organ injury local trigger + =

Intervention: pharmacologic/ circuit modification approaches

Intervention: clinical management changes

Landis, C. J Extracorpor Technol 2007;39:281 Landis RC. Core Topics in Cardiac Anaesthesia, 2nd Ed. 2009 …

long term strategy

immediate

Adhesion to plastic has been described as “frustrated phagocytosis” and engages inflammatory and ROS signaling pathways

Snerbulent splench-sucker that captures prey by sticking to their faces and suffocating them - its suckers are impossible to prize off. Unfortunately, it can’t catch anything as it can’t move from the rock it was born on.

— “Flanimals” by Ricky Gervase

Underblenge

Platelet activation

Endothelial activation

Thrombin

Bradykinin

Leukocyteactivation

XII

intrinsic coagulation

Kallikrein

fibrinolysis

tPA

Plasmin C3

C5

IgM/IgG

classical complement

white cell adhesion

Oxidative stress

hemolysis/ RBC transf

Platelet activation

Endothelial activation

Bradykinin

Leukocyteactivation

XII

intrinsic coagulation

Kallikrein

fibrinolysis

tPA

Plasmin C3

C5

IgM/IgG

classical complement

white cell adhesion

Oxidative stress

hemolysis/ RBC transf

systemic

local

Thrombin

organ injury

systemic factors

systemic factors organ injury local trigger + =

Intervention: pharmacologic/ circuit modification approaches

Intervention: clinical management changes

Heart Surgery Forum (2008), in press

Imperial College London Betsy Evans Ken Taylor

Edmund Cohen Laboratory Andre Greenidge

Kim Quimby

ICEBP writing group Rob Baker

Jeremiah Brown Donny Likosky

Consensus Statement writing group

Summary of Recommendations:

1, Mandatory description of CPB equipment and perfusion techniques used. See Table 1.

2, Report a minimum of 3 criteria (3 major criteria or 2 major and 1 minor). See Tables 2 & 3:

i.e. 3 major (2 inflammatory and 1 clinical end-point or marker of organ injury)

or

2 major (1 inflammatory and 1 clinical end-point or marker of organ injury) and 1 minor criteria.

OUTCOMES XIII MAY 27-30 2009

systemic local

heart brain kidney gut lung vein grafts X-clamp

• vessel trauma • endothelial denudation

• ischemic injury • endothelial activation

intrinsic coagulation

classical complement

white cell adhesion

fibrinolysis

bleeding humoral, white cell & vascular activation

hemolysis/ RBC transf.

oxidative stress

systemic local

systemic factors

local trigger

Fluid shifts in the brain

“Fixing the heart: must the brain pay the price?” Mark Newman, Circulation 2004

Whole blood PAR1 function assay

FL3

CD14

(M

onoc

yte)

FL1 CD45 (pan-leukocyte)

monocytes

neutrophils

lymphocytes

  Blood samples taken before, during and after CPB

  Platelet binding to leukocytes used as a surrogate for platelet activation

FL2 CD42b (platelet)

7.01 % 2. Determine % of platelets in the leukocyte gate

84.01%

TRAP-6

FL2 CD42b (platelet)

1. Gate on leukocyte subpopulation

3. Assess ability of platelets to be activated via PAR1 by adding PAR1 agonist TRAP-6

( After: Ferraris, V.A., et al. (1998) Ann Thorac Surg 65:352-8)

Aprotinin has a weak Ki for thrombin

Aprotinin Ki (M)

trypsin 6 x 10-11

plasmin 9 x 10-11

plasma kallikrein

3 x 10-8

tissue kallikrein

3 x 10-10

Factor XIIa > 1 x 10-6

Factor XIa 1 x 10-7

elastase > 1 x 10-6

thrombin > 1 x 10-6

Conclusions on mechanism of action

Aprotinin inhibits binding of thrombin to the hirudin-like binding site on PAR1.

Leads to a reduced rate of PAR1 hydrolysis by thrombin.

Fits the inhibitory profile of aprotinin.