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Choreoathetosis as a complication of cardiopulmonary bypass
Choreoathetosis as a Complication of Cardiopulmonary Bypass Brian G. Barratt-Boyes, KBE, MB, ChM "Greenhills," Auckland, New Zealand
N
eurological complications after cardiac operations involving cardiopulmonary bypass (CPB) have a variety of causes. Most are readily apparent, for example, cerebral embolism or hemorrhage or hypoxia, and the lesion responsible is visible on computed tomographic scanning. In addition, with the exception of severe diffuse hypoxic damage, the distribution of neurological signs varies from one patient to another, and is defined by the vascular territory or parts of the brain involved. Choreoathetosis, one of these complications after CPB, does not come into any of these classifications. The full-blown syndrome is rare, and it is tempting to think that severe sustained choreoathetosis may be a different entity from transient mild chorea. The cause is unknown and it is not accompanied by consistently detectable abnormalities on computed tomographic scan, electroencephalography, or any other currently available investigation including brain histology, although in one report [l] abnormalities were detected in the basal nuclei, the likely site of the lesion. The clinical picture is stereotyped and striking and cannot go unrecognized, although it is almost certainly underreported. No patient has been reported outside early childhood. The onset is from 2 to 7 days postoperatively and in most cases there is a clear period of normality beforehand. The severity usually progresses over 1 to 3 weeks and recovery is usually complete.
See also page 714. Most reports of choreoathetosis have implicated profound hypothermia combined with circulatory arrest as the guilty party and, under these circumstances, the arrest temperature has varied between 15" and 2 0 T , except for 1 patient at 9°C [2-61. The circulatory arrest times have varied between 7 and 71 minutes. The syndrome is thus not only associated with longer arrest times. Only 1 case of severe sustained choreoathetosis has been encountered in Auckland. Characteristically it appeared on day 3 after an initially smooth postoperative course in a 4-year-old child having his first operation, which was totally uneventful. The arrest temperature was 18°C nasopharyngeal and the arrest time was 25 minutes. Two milder cases were reported by us in 1970 [4]-these children were aged 8 and 17 months. We are indebted to DeLeon and colleagues [7] for the article in this issue that reports the occurrence of severe Address reprint requests to Sir Brian Barratt-Boyes, "Greenhills," Box 51, Waiwera HBC, Auckland, New Zealand. 0
1990 by The Society of Thoracic Surgeons
choreoathetosis in 8 children aged 1 to 5 years after cardiac operations that employed hypothermic CPB without circulatory arrest. Their report confirms the suspicion gained from the literature of the early 1960s that hypothermic CPB alone can cause choreoathetosis. In these early reports [8, 91, the esophageal temperature varied between 5.8" and 16"C, and it was implied that hypothermia below 16°C was dangerous to brain function. It is somewhat strange that the many others currently using profound hypothermia without circulatory arrest for congenital heart disease operations have not also reported some examples of choreoathetosis, although the recent report from Ferry [lo], which involved a survey of six major pediatric centers using deep hypothermia, implies that some units do see it in the absence of circulatory arrest. DeLeon and colleagues concluded that hypothermic CPB below 25°C rectal predisposes to the occurrence of choreoathetosis when it is associated with a longer cooling time (defined as the length of time the perfusate was kept at or below 25°C) and a higher perfusion flow rate. However, in only one of the affected children was the rectal temperature lowered below 20°C. Most cardiac surgeons believe that hypothermia, at least to a lower limit of 18°C nasopharyngeal, is protective to the brain during CPB. Moreover, a longer cooling time is thought to provide more uniform brain cooling than short cooling times and to be preferable, at least when followed by a period of circulatory arrest. Finally, concern has frequently been expressed that brain damage can follow prolonged periods of low flow and does not occur with high flow per se [ 111. Interpretation of the study of DeLeon and associates presents problems in a number of important respects. First, the range of each of the variables in their 8 children considered to be significant is too wide to be credible. Thus the rectal temperature was 16" to 25°C and the CPB time 75 to 270 minutes with a cooling time of 30 to 179 minutes; the flow rate varied between "low flow" and 2,500 mL * mP2. Before accepting any of the conclusions offered as significant, a multivariate logistic regression analysis of the data is imperative. Second, the assessment of the patients lacks detail with regard to possible preoperative central nervous system impairment (how many had adverse perinatal events such as low birth weight for gestational age, small head circumference, developmental delay, or overt neurological findings?), for in some patients these may be related to postoperative neurological Ann Thorac Surg 1990;50:693-4
0003-4975/90/$3.50
694
EDITORIAL BARRATT-BOYES CHOREOATHETOSIS
and developmental status including choreoathetosis [3-51. In addition, imaging of the brain preoperatively sometimes demonstrates lesions unsuspected clinically that may influence late progress [12]. Clearly the 8 children described belong to a group of severely affected individuals with complex congenital heart disease, and most had a prior intracardiac operation involving hypothermic CPB, which may have been associated with prolonged low flow CPB or particulate embolization, or severe postoperative hypotension with low cardiac output. The suggestion that the hypothermic repair was the factor contributing to choreoathetosis after the reoperation has nothing to support it. Choreoathetosis can occur in a variety of situations disassociated with cardiac surgery. We have seen 1 infant who had choreoathetosis of unknown cause of similar degree before and after operation. Movement disorders may be seen as a side effect of drug therapy [13]. The truth of the matter is that many hundreds of children have undergone hypothermic CPB at temperatures below 25°C and flow rates at or about 100 mL kg-' * min-' and "cooling times" greater than 1 hour, with and without circulatory arrest, without experiencing choreoathetosis. What then is the missing link? The choreoathetosis is presumably due to hypoxic damage to the basal nuclei secondary to a disturbance of cerebral blood flow triggered by some aspect of the CPB technique, with or without the addition of circulatory arrest. The acid-base status could be particularly important in view of its influence on cerebral blood flow, and preoperative cerebral damage may make its occurrence more likely. Detailed reporting of all the factors listed, together with the drugs used perioperatively, should be added to the protocol in the hope of solving the riddle.
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Ann Thorac Surg 1990;50:6934
References 1. Chaves E, Scaltsas-Persson IS. Severe choreoathetosis (CA) following congenital heart disease (CHD) surgery. [abstract] Neurology 1988;38:24. 2. Castenada AR, Lamberti J, Sade RM, Williams RG, Nadas AS. Open-heart surgery during the first three months of life. J Thorac Cardiovasc Surg 1974;68:719-31. 3. Brunberg JA, Reilly EL, Doty DB. Central nervous system consequences in infants of cardiac surgery using deep hypothermia and circulatory arrest. Circulation 1974;49,50:60-6. 4. Clarkson I'M, Barton MB, MacArthur A, Barratt-Boyes BG, Whitlock RM, Neutze JM. Developmental progress after cardiac surgery in infancy using hypothermia and circulatory arrest. Circulation 1980;62:855-61. 5. Robinson RO, Samuels M, I'ohl KRE. Choreic syndrome after cardiac surgery. Arch Dis Child 1988;63:1466-9. 6. Greeley WJ, Ungerleider RM, Smith LR, Reves JG. The effects of deep hypothermic cardiopulmonary bypass and total circulatory arrest on cerebral blood flow in infants and children. J Thorac Cardiovasc Surg 1989;97:73745. 7. DeLeon S, Ilbawi M, Arcilla R, et al. Choreoathetosis after deep hypothermia without circulatory arrest. Ann Thorac Surg 1990;50:714-9. 8. Bjork VO, Hultquist G. Brain damage in children after deep hypothermia. Thorax 1960;15:284-91. 9. Egerton N, Egerton WS, Kay JH. Neurologic changes following profound hypothermia. Ann Surg 1962;157:366-73. 10. Ferry PC. Neurologic sequelae of open-heart surgery in children. Am J Dis Child 1990;144:369-78. 11. Kirklin JW, Barratt-Boyes BG. Cardiac surgery. New York: Wiley, 1986:3043. 12. McConnell JR, Fleming WH, Chu W-K, et al. Magnetic resonance imaging of the brain in infants before and after cardiac surgery. Am J Dis Child 1990;144:374-8. 13. American College of Neuropsychopharmacology-food and drug administration task force. Neurologic syndromes associated with antipsychotic drug use. N Engl J Med 1973;209:2@3.
N
eurological complications after cardiac operations involving cardiopulmonary bypass (CPB) have a variety of causes. Most are readily apparent, for example, cerebral embolism or hemorrhage or hypoxia, and the lesion responsible is visible on computed tomographic scanning. In addition, with the exception of severe diffuse hypoxic damage, the distribution of neurological signs varies from one patient to another, and is defined by the vascular territory or parts of the brain involved. Choreoathetosis, one of these complications after CPB, does not come into any of these classifications. The full-blown syndrome is rare, and it is tempting to think that severe sustained choreoathetosis may be a different entity from transient mild chorea. The cause is unknown and it is not accompanied by consistently detectable abnormalities on computed tomographic scan, electroencephalography, or any other currently available investigation including brain histology, although in one report [l] abnormalities were detected in the basal nuclei, the likely site of the lesion. The clinical picture is stereotyped and striking and cannot go unrecognized, although it is almost certainly underreported. No patient has been reported outside early childhood. The onset is from 2 to 7 days postoperatively and in most cases there is a clear period of normality beforehand. The severity usually progresses over 1 to 3 weeks and recovery is usually complete.
See also page 714. Most reports of choreoathetosis have implicated profound hypothermia combined with circulatory arrest as the guilty party and, under these circumstances, the arrest temperature has varied between 15" and 2 0 T , except for 1 patient at 9°C [2-61. The circulatory arrest times have varied between 7 and 71 minutes. The syndrome is thus not only associated with longer arrest times. Only 1 case of severe sustained choreoathetosis has been encountered in Auckland. Characteristically it appeared on day 3 after an initially smooth postoperative course in a 4-year-old child having his first operation, which was totally uneventful. The arrest temperature was 18°C nasopharyngeal and the arrest time was 25 minutes. Two milder cases were reported by us in 1970 [4]-these children were aged 8 and 17 months. We are indebted to DeLeon and colleagues [7] for the article in this issue that reports the occurrence of severe Address reprint requests to Sir Brian Barratt-Boyes, "Greenhills," Box 51, Waiwera HBC, Auckland, New Zealand. 0
1990 by The Society of Thoracic Surgeons
choreoathetosis in 8 children aged 1 to 5 years after cardiac operations that employed hypothermic CPB without circulatory arrest. Their report confirms the suspicion gained from the literature of the early 1960s that hypothermic CPB alone can cause choreoathetosis. In these early reports [8, 91, the esophageal temperature varied between 5.8" and 16"C, and it was implied that hypothermia below 16°C was dangerous to brain function. It is somewhat strange that the many others currently using profound hypothermia without circulatory arrest for congenital heart disease operations have not also reported some examples of choreoathetosis, although the recent report from Ferry [lo], which involved a survey of six major pediatric centers using deep hypothermia, implies that some units do see it in the absence of circulatory arrest. DeLeon and colleagues concluded that hypothermic CPB below 25°C rectal predisposes to the occurrence of choreoathetosis when it is associated with a longer cooling time (defined as the length of time the perfusate was kept at or below 25°C) and a higher perfusion flow rate. However, in only one of the affected children was the rectal temperature lowered below 20°C. Most cardiac surgeons believe that hypothermia, at least to a lower limit of 18°C nasopharyngeal, is protective to the brain during CPB. Moreover, a longer cooling time is thought to provide more uniform brain cooling than short cooling times and to be preferable, at least when followed by a period of circulatory arrest. Finally, concern has frequently been expressed that brain damage can follow prolonged periods of low flow and does not occur with high flow per se [ 111. Interpretation of the study of DeLeon and associates presents problems in a number of important respects. First, the range of each of the variables in their 8 children considered to be significant is too wide to be credible. Thus the rectal temperature was 16" to 25°C and the CPB time 75 to 270 minutes with a cooling time of 30 to 179 minutes; the flow rate varied between "low flow" and 2,500 mL * mP2. Before accepting any of the conclusions offered as significant, a multivariate logistic regression analysis of the data is imperative. Second, the assessment of the patients lacks detail with regard to possible preoperative central nervous system impairment (how many had adverse perinatal events such as low birth weight for gestational age, small head circumference, developmental delay, or overt neurological findings?), for in some patients these may be related to postoperative neurological Ann Thorac Surg 1990;50:693-4
0003-4975/90/$3.50
694
EDITORIAL BARRATT-BOYES CHOREOATHETOSIS
and developmental status including choreoathetosis [3-51. In addition, imaging of the brain preoperatively sometimes demonstrates lesions unsuspected clinically that may influence late progress [12]. Clearly the 8 children described belong to a group of severely affected individuals with complex congenital heart disease, and most had a prior intracardiac operation involving hypothermic CPB, which may have been associated with prolonged low flow CPB or particulate embolization, or severe postoperative hypotension with low cardiac output. The suggestion that the hypothermic repair was the factor contributing to choreoathetosis after the reoperation has nothing to support it. Choreoathetosis can occur in a variety of situations disassociated with cardiac surgery. We have seen 1 infant who had choreoathetosis of unknown cause of similar degree before and after operation. Movement disorders may be seen as a side effect of drug therapy [13]. The truth of the matter is that many hundreds of children have undergone hypothermic CPB at temperatures below 25°C and flow rates at or about 100 mL kg-' * min-' and "cooling times" greater than 1 hour, with and without circulatory arrest, without experiencing choreoathetosis. What then is the missing link? The choreoathetosis is presumably due to hypoxic damage to the basal nuclei secondary to a disturbance of cerebral blood flow triggered by some aspect of the CPB technique, with or without the addition of circulatory arrest. The acid-base status could be particularly important in view of its influence on cerebral blood flow, and preoperative cerebral damage may make its occurrence more likely. Detailed reporting of all the factors listed, together with the drugs used perioperatively, should be added to the protocol in the hope of solving the riddle.
-
Ann Thorac Surg 1990;50:6934
References 1. Chaves E, Scaltsas-Persson IS. Severe choreoathetosis (CA) following congenital heart disease (CHD) surgery. [abstract] Neurology 1988;38:24. 2. Castenada AR, Lamberti J, Sade RM, Williams RG, Nadas AS. Open-heart surgery during the first three months of life. J Thorac Cardiovasc Surg 1974;68:719-31. 3. Brunberg JA, Reilly EL, Doty DB. Central nervous system consequences in infants of cardiac surgery using deep hypothermia and circulatory arrest. Circulation 1974;49,50:60-6. 4. Clarkson I'M, Barton MB, MacArthur A, Barratt-Boyes BG, Whitlock RM, Neutze JM. Developmental progress after cardiac surgery in infancy using hypothermia and circulatory arrest. Circulation 1980;62:855-61. 5. Robinson RO, Samuels M, I'ohl KRE. Choreic syndrome after cardiac surgery. Arch Dis Child 1988;63:1466-9. 6. Greeley WJ, Ungerleider RM, Smith LR, Reves JG. The effects of deep hypothermic cardiopulmonary bypass and total circulatory arrest on cerebral blood flow in infants and children. J Thorac Cardiovasc Surg 1989;97:73745. 7. DeLeon S, Ilbawi M, Arcilla R, et al. Choreoathetosis after deep hypothermia without circulatory arrest. Ann Thorac Surg 1990;50:714-9. 8. Bjork VO, Hultquist G. Brain damage in children after deep hypothermia. Thorax 1960;15:284-91. 9. Egerton N, Egerton WS, Kay JH. Neurologic changes following profound hypothermia. Ann Surg 1962;157:366-73. 10. Ferry PC. Neurologic sequelae of open-heart surgery in children. Am J Dis Child 1990;144:369-78. 11. Kirklin JW, Barratt-Boyes BG. Cardiac surgery. New York: Wiley, 1986:3043. 12. McConnell JR, Fleming WH, Chu W-K, et al. Magnetic resonance imaging of the brain in infants before and after cardiac surgery. Am J Dis Child 1990;144:374-8. 13. American College of Neuropsychopharmacology-food and drug administration task force. Neurologic syndromes associated with antipsychotic drug use. N Engl J Med 1973;209:2@3.