Retrograde cerebral perfusion enhances cerebral protection during prolonged hypothermic circulatory arrest: a study in a chronic porcine model.
BACKGROUND
This study was undertaken to confirm earlier findings that retrograde cerebral perfusion (RCP) can improve cerebral outcome after prolonged hypothermic circulatory arrest (HCA), and to determine whether RCP with inferior vena caval occlusion, which is more effective in removing particulate emboli, is superior to conventional RCP in enhancing cerebral protection.


METHODS
Sixty-two pigs (27 to 30 kg) were randomly assigned to undergo one of the following for 90 minutes at 20 degrees C: antegrade cerebral perfusion (ACP); conventional RCP (RCP); RCP with occlusion of the inferior vena cava (RCP-O), or HCA with the head packed in ice. RCP flow was regulated to a sagittal sinus pressure of 20 mm Hg. Hemodynamic, electrophysiologic, and metabolic monitoring were carried out until 4 hours after rewarming, daily behavioral and neurologic assessments until elective sacrifice on day 7, and histologic analysis of the brain after death.


RESULTS
Complete behavioral recovery was seen in all surviving animals by day 5 after ACP or RCP, but in only 83% after RCP-O and 50% after HCA (p = 0.001). A histopathologic score of 2 or more, indicating more than mild injury, was not found in any animal after ACP, in 27% after RCP, in 47% after HCA, and in 68% after RCP-O (p = 0.002). The median oxygen consumption was 6.66 mL/min after ACP, 1.37 mL/min with RCP, and 1.02 mL/min with RCP-O (p < 0.0001). The median amount of fluid sequestered was 2,450 mL after RCP-O, 760 mL after RCP, and -200 mL after ACP (p < 0.0001).


CONCLUSIONS
Conventional RCP without inferior vena caval occlusion results in a significantly better outcome than RCP-O after prolonged HCA, despite more efficient cerebral perfusion during RCP-O, and also provides cerebral protection superior to prolonged HCA alone, but care must be taken during its implementation to minimize cerebral edema and other possible causes of retroperfusion-related cerebral injury.
Department of Cardiothoracic Surgery, The Mount Sinai Medical Center, New York, New York, USA. tatu.juvonen@oulu.fi
T
T
Juvonen
N
N
Zhang
D
D
Wolfe
D J
DJ
Weisz
C A
CA
Bodian
H H
HH
Shiang
J N
JN
McCullough
R B
RB
Griepp
D000818:Animals; D001522:Behavior, Animal; D001921:Brain / Q000098:blood supply / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D001929:Brain Edema / Q000209:etiology / Q000473:pathology; D002545:Brain Ischemia / Q000209:etiology / Q000473:pathology; D002315:Cardiopulmonary Bypass / Q000379:methods*; D002544:Cerebral Infarction / Q000209:etiology / Q000473:pathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003250:Constriction; D004195:Disease Models, Animal; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D006324:Heart Arrest, Induced; D006439:Hemodynamics; D007036:Hypothermia, Induced; D002542:Intracranial Embolism and Thrombosis / Q000517:prevention & control; D009460:Neurologic Examination; D010101:Oxygen Consumption / Q000502:physiology; D011897:Random Allocation; D017694:Rewarming; D013552:Swine; D014682:Vena Cava, Inferior