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Retrograde cerebral perfusion in human brains
RESEARCH LETTERS
Research letters
Retrograde cerebral perfusion in human brains Takayuki Ono, Yutaka Okita, Motomi Ando, Soichiro Kitamura
Deep hypothermic circulatory arrest with retrograde cerebral perfusion (RCP) is a valuable technique for cerebral protection in aortic-arch surgery.1 Although how RCP protects the brain is not entirely understood, the clinical benefits are postulated to be the maintenance of cerebral hypothermia and the flushing of air and particulate debris from the arterial circulation. Nevertheless, whether blood goes through a cerebral capillary bed in a retrograde fashion during circulatory arrest has not been proved.2–4 Because the retina develops from the forebrain, retinal circulation is thought to represent the cerebrovascular circulation. We investigated whether RCP does occur in the human brain by observing retinal circulation during deep hypothermic circulatory arrest with use of fluorescein retinal angiography.5 Between December, 1998, and April, 1999, five patients (three men, two women, mean age 35·4 years [range 22–50]) undergoing aortic-arch surgery gave written informed consent for injection of fluorescein during RCP. Primary diagnoses included Marfan’s syndrome in two patients, Takayasu’s disease in two, and Behçet’s disease in one. These patients had no history of cataract, glaucoma, or allergic reaction to fluorescein. We dilated patients’ pupils with 1% tropicamide eye drops after induction of anaesthesia. RCP was done with use of cardiopulmonary bypass. Connection of the arterial and venous lines of the bypass ciruit reversed the flow into the superior vena cava (SVC) cannula and was started
400 350 SVC-retina time (s)
Retrograde cerebral perfusion via the superior vena cava during deep hypothermic circulatory arrest has evolved as a means of cerebral protection in aortic-arch surgery. We showed, with use of fluorescein retinal angiography, that during retrograde cerebral perfusion, fluorescein injected into the superior vena cava entered the retinal venules, flowed to the capillaries, and subsequently, to the retinal arterioles. Since the retina is embryologically part of the brain, we conclude that this procedure does allow blood to perfuse in a retrograde way through the human brain.
150 100
r=0·991, p=0·001 0
50 100 150 200 250 300 350 400 450 500 Flow (mL/min)
Figure 2: Relation between flow rate and SVC-retina time
after circulatory arrest at a nasopharyngeal temperature of less than 18ºC. RCP flow pressure was maintained at 18–20 mm Hg in the internal jugular vein and the flow ranged from 150 mL/min to 500 mL/min. 15 mg/kg fluorescein was injected as a bolus into the SVC cannula and rapid sequential retinal photographs were taken by a portable fundus camera. In all patients, fluorescein first appeared in the axial central part of the retinal venules. During the course of angiography, fluorescein was seen sequentially in the retinal capillaries and arterioles (figure 1). The time between injection of fluorescein and the appearance of fluorescein in the central retinal veins (SVC-retina time) ranged from 170 s to 360 s (mean 254·8 s [SD 74·3]). RCP flow rates and SVC-retina time correlated inversely (figure 2). All patients were extubated within 24 h of surgery and none had postoperative neurological dysfunction. Blood did perfuse in a retrograde way from the SVC to the retinal venules, capillary and retinal arterioles during circulatory arrest. We conclude, therefore, that RCP does allow blood to perfuse the human brain during deep hypothermic circulatory arrest.
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THE LANCET • Vol 356 • October 14, 2000
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0
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A=before RCP; B=fluorescein in retinal venules during RCP; C=fluorescein in capillaries; D=fluorescein in retinal arterioles.
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1
Figure 1: Fundus photography before and during RCP
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Ueda Y, Miki S, Kusuhara K, Okita Y, Tahat T, Yamanaka K. Surgical treatment of aneurysm or dissection involving the ascending aorta and aortic arch, utilizing circulatory arrest and retrograde cerebral perfusion. J Cardiovasc Surg 1990; 31: 553–58. Boechxstaens CJ, Flameng WJ. Retrograde cerebral perfusion does not perfuse the brain in nonhuman primates. Ann Thorac Surg 1995; 60: 319–28. de Brux JL, Subayi JB, Pegis JD, Pilet J. Retrograde cerebral perfusion: anatomic study of the distribution of blood to the brain. Ann Thorac Surg 1995; 60: 1294–98. Pagano D, Boivin CM, Faroqui MH, Bonser RS. Retrograde perfusion through the superior vena cava perfuses the brain in human beings. J Thorac Cardiovasc Surg 1996; 111: 270–72. Blauth C, Arnold J, Kohner EM, Taylor KM. Retinal microembolism during cardiopulmonary bypass demonstrated by fluorescein angiography. Lancet 1986; 2: 837–39.
Department of Cardiovascular Surgery, National Cardiovascular Centre, 5-7-1 Fujisjirodai, Suita, 565-8565, Osaka, Japan (T Ono MD, Y Okita MD, M Ando MD, S Kitamura MD) Correspondence to: Dr Takayuki Ono (e-mail: [email protected])
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For personal use only. Not to be reproduced without permission of The Lancet.
Research letters
Retrograde cerebral perfusion in human brains Takayuki Ono, Yutaka Okita, Motomi Ando, Soichiro Kitamura
Deep hypothermic circulatory arrest with retrograde cerebral perfusion (RCP) is a valuable technique for cerebral protection in aortic-arch surgery.1 Although how RCP protects the brain is not entirely understood, the clinical benefits are postulated to be the maintenance of cerebral hypothermia and the flushing of air and particulate debris from the arterial circulation. Nevertheless, whether blood goes through a cerebral capillary bed in a retrograde fashion during circulatory arrest has not been proved.2–4 Because the retina develops from the forebrain, retinal circulation is thought to represent the cerebrovascular circulation. We investigated whether RCP does occur in the human brain by observing retinal circulation during deep hypothermic circulatory arrest with use of fluorescein retinal angiography.5 Between December, 1998, and April, 1999, five patients (three men, two women, mean age 35·4 years [range 22–50]) undergoing aortic-arch surgery gave written informed consent for injection of fluorescein during RCP. Primary diagnoses included Marfan’s syndrome in two patients, Takayasu’s disease in two, and Behçet’s disease in one. These patients had no history of cataract, glaucoma, or allergic reaction to fluorescein. We dilated patients’ pupils with 1% tropicamide eye drops after induction of anaesthesia. RCP was done with use of cardiopulmonary bypass. Connection of the arterial and venous lines of the bypass ciruit reversed the flow into the superior vena cava (SVC) cannula and was started
400 350 SVC-retina time (s)
Retrograde cerebral perfusion via the superior vena cava during deep hypothermic circulatory arrest has evolved as a means of cerebral protection in aortic-arch surgery. We showed, with use of fluorescein retinal angiography, that during retrograde cerebral perfusion, fluorescein injected into the superior vena cava entered the retinal venules, flowed to the capillaries, and subsequently, to the retinal arterioles. Since the retina is embryologically part of the brain, we conclude that this procedure does allow blood to perfuse in a retrograde way through the human brain.
150 100
r=0·991, p=0·001 0
50 100 150 200 250 300 350 400 450 500 Flow (mL/min)
Figure 2: Relation between flow rate and SVC-retina time
after circulatory arrest at a nasopharyngeal temperature of less than 18ºC. RCP flow pressure was maintained at 18–20 mm Hg in the internal jugular vein and the flow ranged from 150 mL/min to 500 mL/min. 15 mg/kg fluorescein was injected as a bolus into the SVC cannula and rapid sequential retinal photographs were taken by a portable fundus camera. In all patients, fluorescein first appeared in the axial central part of the retinal venules. During the course of angiography, fluorescein was seen sequentially in the retinal capillaries and arterioles (figure 1). The time between injection of fluorescein and the appearance of fluorescein in the central retinal veins (SVC-retina time) ranged from 170 s to 360 s (mean 254·8 s [SD 74·3]). RCP flow rates and SVC-retina time correlated inversely (figure 2). All patients were extubated within 24 h of surgery and none had postoperative neurological dysfunction. Blood did perfuse in a retrograde way from the SVC to the retinal venules, capillary and retinal arterioles during circulatory arrest. We conclude, therefore, that RCP does allow blood to perfuse the human brain during deep hypothermic circulatory arrest.
3
4
5
THE LANCET • Vol 356 • October 14, 2000
200
0
2
A=before RCP; B=fluorescein in retinal venules during RCP; C=fluorescein in capillaries; D=fluorescein in retinal arterioles.
250
50
1
Figure 1: Fundus photography before and during RCP
300
Ueda Y, Miki S, Kusuhara K, Okita Y, Tahat T, Yamanaka K. Surgical treatment of aneurysm or dissection involving the ascending aorta and aortic arch, utilizing circulatory arrest and retrograde cerebral perfusion. J Cardiovasc Surg 1990; 31: 553–58. Boechxstaens CJ, Flameng WJ. Retrograde cerebral perfusion does not perfuse the brain in nonhuman primates. Ann Thorac Surg 1995; 60: 319–28. de Brux JL, Subayi JB, Pegis JD, Pilet J. Retrograde cerebral perfusion: anatomic study of the distribution of blood to the brain. Ann Thorac Surg 1995; 60: 1294–98. Pagano D, Boivin CM, Faroqui MH, Bonser RS. Retrograde perfusion through the superior vena cava perfuses the brain in human beings. J Thorac Cardiovasc Surg 1996; 111: 270–72. Blauth C, Arnold J, Kohner EM, Taylor KM. Retinal microembolism during cardiopulmonary bypass demonstrated by fluorescein angiography. Lancet 1986; 2: 837–39.
Department of Cardiovascular Surgery, National Cardiovascular Centre, 5-7-1 Fujisjirodai, Suita, 565-8565, Osaka, Japan (T Ono MD, Y Okita MD, M Ando MD, S Kitamura MD) Correspondence to: Dr Takayuki Ono (e-mail: [email protected])
1323
For personal use only. Not to be reproduced without permission of The Lancet.