SHA24/083003

Surgery of thoracic aorta on circulatory arrest Antonio Maria CALAFIORE

Professor of Cardiac Surgery Director, Department of Adult Cardiac Surgery Prince Sultan Cardiac Center Riyadh Kingdom of Saudi Arabia

Surgery of thoracic aorta is strictly related to circulatory arrest and cerebral protection during brain ischemia.

The adult brain constitutes 2% of the body mass but uses 15% of the total energy generated by body metabolism. The main source of neuronal energy, adenosine triphosphate (ATP), is generated through aerobic glycolysis.

The adult brain constitutes 2% of the body mass but uses 15% of the total energy generated by body metabolism. The main source of neuronal energy, adenosine triphosphate (ATP), is generated through aerobic glycolysis.

Glucose AEROBIC GLYCOLYSIS

38 molecules ATP

The adult brain constitutes 2% of the body mass but uses 15% of the total energy generated by body metabolism. The main source of neuronal energy, adenosine triphosphate (ATP), is generated through aerobic glycolysis.

Glucose AEROBIC GLYCOLYSIS

38 molecules ATP

Glucose ANAEROBIC GLYCOLYSIS

2 molecules Insufficient ATP Toxic +lactate

Although glucose is its primary substrate for energy generation, the brain has no glucose or glycogen stores.

Lassen NA. Autoregulation of cerebral blood flow. Circ Res 1964;15:1201–4

Although glucose is its primary substrate for energy generation, the brain has no glucose or glycogen stores.

To sustain active metabolism, the brain, therefore, requires a constant supply of glucose (60 mg/100g of brain tissue) and oxygen (3-4 mL/100g), and a regulated blood flow (50 mL/100g) to maintain appropriate function.

Lassen NA. Autoregulation of cerebral blood flow. Circ Res 1964;15:1201–4

Ischemic-anoxic brain injury Cerebral injuries during surgery on the thoracic aorta which requires temporary exclusion of the cerebral circulation can be divided in

Ischemic-anoxic brain injury Cerebral injuries during surgery on the thoracic aorta which requires temporary exclusion of the cerebral circulation can be divided in temporary neurologic dysfunction, due to interrupted or inadequate flow (global ischemia)

Ischemic-anoxic brain injury Cerebral injuries during surgery on the thoracic aorta which requires temporary exclusion of the cerebral circulation can be divided in temporary neurologic dysfunction, due to interrupted or inadequate flow (global ischemia) localized strokes, caused by ischemic infarcts, and due to embolic events.

For many years DHCA was the most diffuse technique of cerebral protection in aortic surgery.

Retrograde Cerebral Perfusion became popular as an adjunct to DHCA in the early 90’s.

Retrograde Cerebral Perfusion became popular as an adjunct to DHCA in the early 90’s.

Anterior Cerebral Perfusion, revisited in the late ‘90s, is widely used and allows long periods (>60 min) of DHCA with a reasonable low cerebral morbidity.

Anyway, independently from the technique used, incidence of permanent cerebral accidents vary from 4 to 10% and incidence of temporary neurologic dysfunctions range from 5 to 20%, related to the length of CA and to the age.

16 pigs underwent 90 min of circulatory arrest at 20째C.

Group 1: rewarming was started immediately Group 2: rewarming was started after 20 min of cold reperfusion at 20째C and at low pressure (mean 50 mmHg)

Ehrlich MP et al. Cerebral effects of cold reperfusion after hypothermic circulatory arrest. J Thorac Cardiovasc Surg 2001;121:923-31

16 pigs underwent 90 min of circulatory arrest at 20째C.

Group 1: rewarming was started immediately Group 2: rewarming was started after 20 min of cold reperfusion at 20째C and at low pressure (mean 50 mmHg) intracranial pressure mmHg ns

p 0.011

p 0.000

p 0.006

p 0.011

ns

group 1 group 2

Ehrlich MP et al. Cerebral effects of cold reperfusion after hypothermic circulatory arrest. J Thorac Cardiovasc Surg 2001;121:923-31

16 pigs underwent 90 min of circulatory arrest at 20째C.

Group 1: rewarming was started immediately Group 2: rewarming was started after 20 min of cold reperfusion at 20째C and at low pressure (mean 50 mmHg)

All pigs with ICP >15 mmHg (n=3) were positive for histopathological damages and all were in Group 1.

Ehrlich MP et al. Cerebral effects of cold reperfusion after hypothermic circulatory arrest. J Thorac Cardiovasc Surg 2001;121:923-31

16 pigs underwent 90 min of circulatory arrest at 20°C.

Group 1: rewarming was started immediately Group 2: rewarming was started after 20 min of cold reperfusion at 20°C and at low pressure (mean 50 mmHg)

All pigs with ICP >15 mmHg (n=3) were positive for histopathological damages and all were in Group 1.

3 pigs out of the 13 with ICP ≤15 mmHg were positive for histopathological damages, p=0.04.

Ehrlich MP et al. Cerebral effects of cold reperfusion after hypothermic circulatory arrest. J Thorac Cardiovasc Surg 2001;121:923-31

16 pigs underwent 90 min of circulatory arrest at 20째C.

Group 1: rewarming was started immediately Group 2: rewarming was started after 20 min of cold reperfusion at 20째C and at low pressure (mean 50 mmHg)

Cold reperfusion may decrease cerebral edema and thereby improve outcome after prolonged hypothermic circulatory arrest.

Ehrlich MP et al. Cerebral effects of cold reperfusion after hypothermic circulatory arrest. J Thorac Cardiovasc Surg 2001;121:923-31

Rationale of delayed rewarming is to avoid electrical hyperactivity of the energy-depleted brain after an ischemic period, as it can produce extensive damage, recreating a cellular energetic mismatch.

January 1988 to April 2009 DHCA for ascending aorta and/or arch surgery (n=456)

lowest temperature in all patients: 20째C

acute n=217, n=47.6%

chronic n=239, 52.4% Di Mauro M et al. Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest. Eur J Cardiothorac Surg 2013;43:168-73

January 1988 to April 2009 DHCA for ascending aorta and/or arch surgery (n=456)

lowest temperature in all patients: 20째C sDHCA n=69, 15.1%

ACP n=189, 41.5%

RCP n=198, 43.4%

Di Mauro M et al. Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest. Eur J Cardiothorac Surg 2013;43:168-73

January 1988 to April 2009 DHCA for ascending aorta and/or arch surgery (n=456)

median duration of circulatory arrest (from 12 to 156 min) p ns

33

30

31

30

Di Mauro M et al. Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest. Eur J Cardiothorac Surg 2013;43:168-73

January 1988 to April 2009 DHCA for ascending aorta and/or arch surgery (n=456) subclavian 21.0%

arterial inflow

n

aneurysm 7.1%

femoral 71.9%

177 151

chronic acute

p ns

58

p 0.000

40

32 0

Di Mauro M et al. Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest. Eur J Cardiothorac Surg 2013;43:168-73

January 1988 to April 2009 DHCA for ascending aorta and/or arch surgery (n=456)

incidence of neurologic events

yes n=58,12.7% TND n=22, n=4.8%

stroke n=36, n=7.9%

no n=398, 87.3% Di Mauro M et al. Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest. Eur J Cardiothorac Surg 2013;43:168-73

January 1988 to April 2009 DHCA for ascending aorta and/or arch surgery (n=456)

neurologic events and cerebral protection total stroke TND

p ns

% 17.4 13.0 4.3

14.6 7.6 7.0

9.0

5.8

3.2

Di Mauro M et al. Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest. Eur J Cardiothorac Surg 2013;43:168-73

January 1988 to April 2009 DHCA for ascending aorta and/or arch surgery (n=456)

neurologic events and CA duration (cutoff 30 min) p <0.001

%

total stroke TND

25.2 15.2 10.0 2.0 1.6 0.4

Di Mauro M et al. Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest. Eur J Cardiothorac Surg 2013;43:168-73

January 1988 to April 2009 DHCA for ascending aorta and/or arch surgery (n=456)

neurologic events, cerebral protection and CA duration â&#x2030;¤30 min (n=247) total stroke TND

p ns

%

2.6

0

2.6

0 0

3.6 3.6 0

0

Di Mauro M et al. Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest. Eur J Cardiothorac Surg 2013;43:168-73

January 1988 to April 2009 DHCA for ascending aorta and/or arch surgery (n=456)

neurologic events, cerebral protection and CA duration >30 min (n=210) %

total stroke TND

ACP OR 5.1 (2.5-10.5)

35.5 29.0

29.0

15.014.0 6.5

16.5 8.9 7.6

Di Mauro M et al. Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest. Eur J Cardiothorac Surg 2013;43:168-73

January 1988 to April 2009 DHCA for ascending aorta and/or arch surgery (n=456)

rewarming strategy prompt rewarming n=209 45.8%

10 min cold reperfusion n=247 54.2%

Di Mauro M et al. Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest. Eur J Cardiothorac Surg 2013;43:168-73

January 1988 to April 2009 DHCA for ascending aorta and/or arch surgery (n=456)

neurologic events and rewarming strategy total stroke TND

p <0.001

%

13.4 10.5 6.5 2.9

5.3 1.2

rewarming Di Mauro M et al. Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest. Eur J Cardiothorac Surg 2013;43:168-73

January 1988 to April 2009 DHCA for ascending aorta and/or arch surgery (n=456)

neurologic events, rewarming strategy and CA duration (cutoff 40 min) cold reperfusion prompt rewarming

%

p ns

32.9

25.4 p <0.001 11.0 1.6

Di Mauro M et al. Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest. Eur J Cardiothorac Surg 2013;43:168-73

January 1988 to April 2009 DHCA for ascending aorta and/or arch surgery (n=456)

Multivariate analysis showed that DHCA without cold reperfusion was a risk factor for higher incidence of 8.7

(3.4-12.2)

OR

5

(2.7-9.1)

4.1

(2.1-8.5)

1.9

(1.1-3.4)

Di Mauro M et al. Cold reperfusion before rewarming reduces neurological events after deep hypothermic circulatory arrest. Eur J Cardiothorac Surg 2013;43:168-73

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59

strategy for circulatory arrest @ temperature is lowered till 20°C @ single suture technique or expected CA time ≤40 min: sDHCA @ multiple suture technique or expected CA >40 min: ACP using subclavian artery cannulation or direct cannulation @ when CPB is restarted, the temperature is maintained at 20°C for 10 min before rewarming.

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59 no circulatory arrest n=33, 55.9%

on circulatory arrest n=26, 44.1%

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59 (on CA n=26) chronic n=23, 88.5%

acute n=3, 11.5%

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59 age 47±17

43±16 p ns

y 11.5% ≥70 yo

12.1% ≥70 yo

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59 ejection fraction 52±11

52±12 p ns

% 23.1% ≤40%

21.2% ≤40%

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59 log EuroSCORE

%

7.2±3.3 18.2% ≥10

8.3±4.3 p ns 15.4% ≥10

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59 surgical timing p ns

min

165±29 150±47

CA no CA yes p ns 121±33 114±24

22±12 7.7% >30

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59 cannulation sites 23

CA no CA yes

n

10 13

10 3 0

0

0

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59 surgical details CA no (n=33) CA yes (n=26) Bentall 17 12 AA repl 4 AA repl + AVR 11 2 AA repl + arch 3 AA repl + arch + AVR 7 AA repl + arch + ETr 2 David 2 MV surgery 13 3 TV repair 5 2 CABG 3 2

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59

preoperative CT angio

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59

preoperative CT angio

CT angio 3 months after surgery

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59 in-hospital mortality 6.1

%

3.4

0

Department of Adult Cardiac Surgery Prince Sultan Cardiac Center, Riyadh, Saudi Arabia May 2009 to February 2013 thoracic aorta surgery n=59 postoperative details CA no (n=33) time-to-extubation (h) 14±21 (7) redo for bleeding (n) ICU stay (d)

(3-115)

3 (9.1%) 3.0±4.0 (2)

CA yes (n=26) 11±4 (10) (4-19) 1 (3.8%)

(3-115)

postop stay (d)

11.6±9.6 (8)

neurologic event

1 (delayed awaking)

2.3±2.6 (1) (1-10) 13.8±7.5 (11) 0

Conclusion Using appropriate strategies, circulatory arrest does not add any risk to thoracic aorta surgery.

Conclusion Using appropriate strategies, circulatory arrest does not add any risk to thoracic aorta surgery.

Use of delayed rewarming improves cerebral outcome, limiting the incidence of neurologic dysfunction.