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Minimising Cardiotomy Suction induced risk
of fat embolism in patients undergoing cardiac
surgery with Cardiopulmonary Bypass
Ahmed Ajzan MD, Clive Weston FRCP, Pankaj Kumar FRCS
Morriston Hospital, Swansea United Kingdom
Swansea University School of Medicine, United Kingdom

Declaration
This study was funded by Astra ® Sweden without
input into sampling, randomisation or the research
data

Complications of CPB
• Neurological/Neuropsychological dysfunction with CPB
• Stroke at 20% in 1973, 8% in 1982 and 3% in 1995
• Neuropsychological dysfunction recognised in up to 50%
• Study of 46 brain tissues of patients who died after cardiac
surgery with CPB showed only 9 had normal brain tissue
Brierley JB . Brain damage complicating open heart surgery: a neuropathological study of
46 patients. Proc.R.Soc.Med . 1967 :60(9):858-9

Studies in the incidence of Neurological and
Neuropsychological deficit
Author Year Incidence of
Neurological
deficit
Sontaniemi 1983 39%
Breuer 1983 17%
Carrella 1988 48%
Strenge 1992 51%
Murkin 1995 38%

•Diffused brain damage (type II injury) Ranging from visual field
defects to hyper-reflexia to more long term persistent neurological
deficits that involve intellectual and cognitive functions without
localizing or focal signs that are attributed to the CPB
Van Dijk D, Keizer AM, Diephuis JC, Durand C, Vos LJ, Hijman R. Neurocognetive dysfunction after coronary
artery bypass surgery: a systematic review. J Cardiovasc Surg.2000;120:632-9
•Pericardial Suction Blood (PSB) used to recycle blood during
cardiac surgery with cardiopulmonary bypass is a major source of
fat re-introduction
Caguin F, Carter MG. Fat embolisation with cardiotomy with the use of cardiopulmonary bypass. J Cardiovasc
Surg.1963;46:665-72

3 Major causes of Cerebral injury During
cardiac surgery with CBP
• Global or regional cerebral hypoperfusion
• Macroemboli
• Microemboli
Moody DM, Bell MA, Challa VR, Johnston WE, Prough DS. Brain microemboli during cardiac surgery or
aortography. Ann Neurol.1990;28:477-86

Macroemboli
• Large air bubbles
• Atheromatous debris from valve lesions or aortic plaques
• Intracardiac thrombi
• fat emboli
• Aortic instrumentation
• Excessive surgical manipulation
• size ; > 40 um

Causes of Microemboli
• Air
• Gaseous
• Lipid globules
• Muscle and connective tissue fragments
• Platelets and Leukocyte aggregates
• plastic fragments
• calcified particles
• size ; < 40 um

Microemboli
• Stump and colleagues studied
CABG patients reported, the
number and size emboli
detected via Doppler methods is
directly proportional to the
degree of Neuropsychological
dysfunction .
Okies JE, Goodnight SH, Litchford B, Connel RS,
Starr A et al. Effects of cardiotomy suction
blood extracorporial circulation for coronary
artery bypass surgery. J Thorac Cardiovasc
Surg.1977;74(3):440-4

• It has been feasible to quantify the fat being
generated and mobilised during routine cardiac
surgery with cardiopulmonary bypass and
establish that the current filtration systems are
unable to deal with the generated fat
Ajzan A, Modine T, Punjabi P, Ganeshalingam K, Philips G, Gourlay T et al.
Quantification of fat mobilization in patients undergoing coronary artery
Revascularization using off-pump and on-pump techniques. Extra Corpor Technol. 2006
Jun;38(2):122.

During cardiac surgery fat is
generated and mobilised via
the surgical procedure and
surgical manipulation and can
be re-admitted into the
circulation.
Fat can be measured
biochemically analysed and
compared in a particular
patient or between different
patients.
Existing Filtration methods
are unable to deal with
circulating fat Emboli

Count/dl
counts/dl
2950
Embolic Load of the CABG group
2450
Mid-Bypass Suction
Mid-Bypass Arteial
5900
4900
3900
2900
1900
1950
1450
950
Mid-Bypass Venous
End-Bypass Suction
End-Bypass Arterial
End-Bypass Venous
900
-100
Pre-Op Mid-Bypass End-Bypass
Bypass Time (min)
Suction Arterial Venous
450
-50
0-10 m 10-15 m 15-20 m > 20 m
Size
Ajzan et al

PLAN OF STUDY AND AIMS
To evaluate the effectiveness of a fat filtration
device in minimising the fat emboli mobilised via
the cardiotomy suction during cardiopulmonary
bypass.
Study Design
Prospective Randomised Trial
Consecutive isolated CABG cases (aged 18-80, No
emergencies)

MATERIALS AND METHODS
•Study approved by Ethics & Research committees
•Randomisation via number generator
•Investigator blinded to randomisation & not part of the
surgical team
Single surgical team was to minimise technical variations
•50 consecutive patients (n=50) were consented and
randomised for this study
•25 patients (n=25) had a fat reducing system installed to the
cardiotomy suction line of the CPB and 25 patients (n=25) had
no system installed.

Sampling sites
•Cadiotomy suction vs.
Cardiotomy suction after
the filter
•Arterial line
•Venous line
At :
•Start of bypass time
•Mid bypass
•End of bypass before
coming off

Fat Reducing System
•soft shell reservoir with
two compartments each
able to house 500mls of
cardiotomy suction blood,
separated by a water lock
mechanism
•the filter is manufactured
using uncoated standard
PVC materials identical to
that used in venous
reservoirs
•Appelblad M, Engström KG. Fat
content in pericardial suction blood
and the efficacy of spontaneous density
separation and surface adsorption in a
prototype system for fat reduction .J
Thorac Cardiovasc Surg. 2007
Aug;134(2):366-72..

•Oil Red O stain 1-[4-
(Xylylazo)]-2-
naphthol;solvent red
27 to stain the fat
globules
•size estimation is
established using
microspheres (dyetrack,
Triton
technologies,UK)
(6MILLION/2MLS)(1
5U in size)(violet)

Results

Patient Demographic and surgical data
Filtered Group Non-Filtered Group p value
Mean SD Mean SD
Age 68.56 7.74 66.2 7.14 0.14
Sex(males) 74% 76%
Height(cm) 171.61 7.79 170.23 7.42 0.5274
Weight(Kg) 80.6 8.7 79.2 8.23 0.562
Body Surface Area (m2) 2.03 0.74 1.99 0.68 0.843
No. of Grafts 2.8 0.96 3.12 0.86 0.2205
Euroscore 2.56 1.41 2.48 1.44 0.8435
Surgery Time 120.84 24.66 126.84 11.73 0.2774
CPB Time(min) 87.6 22.6 84.88 29.21 0.55
Cross Clamp Time(min) 55.24 19.4 53.48 20.81 0.65
Cardiotomy shed Blood(mls) 309.72 55 327.44 43 0.2105

• we identified that Embolic load to the
patient during cardiopulmonary bypass is
reflected by the number of fat emboli
greater than 15um that detected arterial line
cannula which pose greater risk to the
patient
• Venous Sample results:
No statistically significant differences were
found in venous samples in both groups at
CPB sampling points

Venous Line Samples

Cardiotomy suction Samples

2500
2000
P < 0.001
1416
count/dl
1500
P < 0.001
1000
P = 0.1001
698
500
335.64
273.32
330 342
0
start of bypass mid bypass end of bypass
filtered group
non-filtered group

Arterial Line Samples

140
120
Mean Embolic Load Counts/dl
p< 0.001
100
p = 0.0209
104.68
80
60
p = 0.646
66
40
35.48
32.56
46.72
50.52
20
0
start of bypass mid bypass end bypass
non filtered
filtered

140
120
Mean Embolic Load Counts/dl
p< 0.001
100
p = 0.0209
104.68
80
60
p = 0.646
66
40
35.48
32.56
46.72
50.52
20
0
start of bypass mid bypass end bypass
non filtered
filtered

Filtered Group
(n=25)
Non-Filtered Group (n=25)
p value
Start of Bypass suction 273.32 +/- 123.34 335.64 +/- 130.60 0.1001
arterial 32.56 +/- 22.14 35.48 +/- 23.97 0.646
Mid Bypass suction 330.0 +/- 119.60) 698.0 +/- 250.61 < 0.001
arterial 46.72 +/- 27.30 46.72 +/- 27.30 0.0209
End of Bypass suction 342.0 +/- 98.26 1416 +/- 485.76 < 0.001
arterial 50.52 +/- 28.47 104.68 +/- 35.87 < 0.001

Conclusion

•we demonstrated in a randomised trial that
fat being generated and mobilised during
cardiac revascularisation with
cardiopulmonary bypass CPB can be
reduced using Fat reducing Systems and
that such reduction can be calculated and
measured at different time intervals during
bypass achieving more than 50% reduction
in Embolic load to the patient in the group
where these systems are used

Study Limitations
•We Acknowledge that the longer the bypass time, the more Fat
Emboli will be generated and mobilised in the cardiopulmonary
bypass circuit
•Longer bypass times and testing this system on more complex cases
including valvular surgery and open chamber surgeries will be
beneficial
•Clinical observations in the form of neuro-psychometric analysis or
fundoscopy in future continuation of this study will help in
demonstrating clinical outcome in using these systems

Our goal

• References
• Gibbon JH Jr.: The development of the heart-lung apparatus. Rev Surg., 1970;(4):231-44
• Becerius J, Gummert JF, Borger MA, Walther T, Doll N, Onnasch JF, et al. Stroke after cardiac
surgery: a risk factor analysis of 16184 consecutive adult patients. Ann Thorac Surg.2003;
75:472-8.
• Newman MF, Krrchner JL, Phillips-Bute B, Gaver V, Grocott H, Jones RH, et al. Neurological
outcome Research group and cardiothoracic Anesthesiology research Endeavours
Investigators. Longitudinal assessment of neurocognetive function after coronary artery
bypasses surgery. N Engl J Med.2001;344:395-402
• Van Dijk D, Keizer AM, Diephuis JC, Durand C, Vos LJ, Hijman R. Neurocognetive dysfunction
after coronary artery bypass surgery: a systematic review. J Cardiovasc Surg.2000;120:632-9
• Moody DM, Bell MA, Challa VR, Johnston WE, Prough DS. Brain microemboli during cardiac
surgery or aortography. Ann Neurol.1990;28:477-86
• Caguin F, Carter MG. Fat embolisation with cardiotomy with the use of cardiopulmonary
bypass. J Cardiovasc Surg.1963;46:665-72
• Brooker RF, Brown WR, Moody DM, Hammon JW,Reboussin DM, Deal DD et al. Cardiotomy
suction: a major source of brain lipid emboli during cardiopulmonary bypass .Ann Thorac Surg.
1998:65 1651-5
• Ajzan A, Modine T, Punjabi P, Ganeshalingam K, Philips G, Gourlay T et al. Quantification of fat
mobilization in patients undergoing coronary artery Revascularization using off-pump and onpump
techniques. Extra Corpor Technol. 2006 Jun;38(2):122.
• Okies JE, Goodnight SH, Litchford B, Connel RS, Starr A et al. Effects of cardiotomy suction
blood extracorporial circulation for coronary artery bypass surgery. J Thorac Cardiovasc
Surg.1977;74(3):440-4
• Appelblad M, Engström KG. Fat content in pericardial suction blood and the efficacy of
spontaneous density separation and surface adsorption in a prototype system for fat
reduction .J Thorac Cardiovasc Surg. 2007 Aug;134(2):366-72..
• Brierley JB . Brain damage complicating open heart surgery: a neuropathological study of 46
patients. Proc.R.Soc.Med . 1967 :60(9):858-9
• Appelblad M, Engström KG. Fat reduction in pericardial suction blood by spontaneous density
separation: an experimental model on human liquid fat versus soya oil. Perfusion. 2003
Mar;18(1):39-45.
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