carotid endarterectomy ( cea ) is a common revascularization treatment for moderate to severe stenosis of the carotid artery34 ) . among treatment - related complications , cerebral hyperperfusion syndrome ( chs ) . the known mechanisms of chs after cea include diminished cerebrovascular reserve , postoperative hypertension , and hyperperfusion lasting more than several hours after cea11,15,22,32 ) . another possible mechanism involves reperfusion by clamping and declamping the internal carotid artery , which produces oxygen - derived free radicals10,31 ) . chs is traditionally characterized by an ipsilateral throbbing headache , eye and face pain , seizures , and focal neurological deficits related to cerebral edema or intracerebral hemorrhage ( ich)3,13,26,29,30,33 ) . the reported prevalence of chs , regardless of revascularization method , varies from 0% through 18.9%1,6,11 - 13,18 - 22,24,25,33,34 ) . because the diagnosis of chs is based on several nonspecific symptoms and the diagnostic definition is not strict , patients may sometimes be misdiagnosed . possible risk factors of chs include hypertension , diabetes mellitus , old age ( 72 years ) , contralateral carotid occlusion , and use of anticoagulant or antiplatelet therapy34 ) . due to improvements in surgical skill and postoperative care , the prevalence of chs appears to have decreased . the authors of two recent studies reported that no patients had chs after cea or carotid stenting13,20 ) . other investigators have suggested that chs is a preventable cause of perioperative stroke following cea5 ) . the aim of this study was to evaluate the role of current intensive care protocols with strict blood pressure ( bp ) control for cea to prevent chs . we retrospectively reviewed the records of all patients receiving cea at our hospital from february 2009 through november 2012 . cea was indicated due to transient ischemic attack ( tia ) , mild cerebral infarction with ipsilateral carotid stenosis ( > 60% ) , or high - grade carotid stenosis ( > 60% ) without associated symptoms17 ) . cerebral blood flow ( cbf ) was measured as regional cerebral blood flow ( rcbf ) by perfusion computed tomography ( pct ) and mean velocity ( vmean ) by transcranial doppler ( tcd ) preoperatively ( within 1 month before cea ) and postoperatively ( within 1 week after cea ) . a total of 18 patients received cea at our institution over the 4-year review period . among the patients , 16 patients who were fully evaluated patient demographics , clinical presentation , stenosis severity , radiological studies , and operative variables were reviewed for each case . post - cea hyperperfusion ( php ) has been defined by 2 standards : 1 ) > 100% increase in rcbf in the anterior cerebral artery ( aca ) territories compared with the preoperative value by perfusion ct2,13 ) ; and 2 ) > 100% increase of the preoperative vmean in the middle cerebral artery ( mca ) without clinical symptoms by tcd25 ) . the definition for chs requires the fulfillment of the following four criteria5 ) : 1 ) occurrence within 30 days after cea ; 2 ) evidence of hyperperfusion on tcd , pct imaging , or systolic bp > 180 mm hg ; 3 ) clinical features such as new headache , seizure , hemiparesis , glasgow coma scale < 15 , or radiological features such as cerebral edema or ich ; and 4 ) no evidence of new cerebral ischemia , postoperative carotid occlusion , and metabolic or pharmacologic causes . cea was performed using the traditional method as described in a previous study17 ) . during cea , shunts were not typically used during the cea . if the clamping time passes above 25 minutes , a silicone shunt was placed . after cea , all patients were transferred directly to an intensive care unit ( icu ) because strict bp control is sometimes difficult when patients come out of anesthesia . the postoperative management protocol is shown in fig . 1 . all patients were managed routinely under continuous sedation for several hours after cea in the icu . anti - hypertensive treatment consisted of intravenous labetalol ( first choice ) continuous infusion and/or bolus infusion . if bp was not controlled , oral clonidine was added . if bp was within the required limits , intravenous anti - hypertensive treatment was tapered as soon as possible and an oral beta - blocker ( labetalol or metoprolol ) was started . when chs was detected , postoperative systemic bp was more stringently controlled to maintain it below 120/80 mm hg . the cerebral perfusion state was routinely evaluated by pct at postoperative 2 days and tcd at postoperative 0 , 2 , and 7 days after cea or on detecting chs . post - cea hyperperfusion ( php ) has been defined by 2 standards : 1 ) > 100% increase in rcbf in the anterior cerebral artery ( aca ) territories compared with the preoperative value by perfusion ct2,13 ) ; and 2 ) > 100% increase of the preoperative vmean in the middle cerebral artery ( mca ) without clinical symptoms by tcd25 ) . the definition for chs requires the fulfillment of the following four criteria5 ) : 1 ) occurrence within 30 days after cea ; 2 ) evidence of hyperperfusion on tcd , pct imaging , or systolic bp > 180 mm hg ; 3 ) clinical features such as new headache , seizure , hemiparesis , glasgow coma scale < 15 , or radiological features such as cerebral edema or ich ; and 4 ) no evidence of new cerebral ischemia , postoperative carotid occlusion , and metabolic or pharmacologic causes . cea was performed using the traditional method as described in a previous study17 ) . during cea , shunts were not typically used during the cea . if the clamping time passes above 25 minutes , a silicone shunt was placed . after cea , all patients were transferred directly to an intensive care unit ( icu ) because strict bp control is sometimes difficult when patients come out of anesthesia . the postoperative management protocol is shown in fig . 1 . all patients were managed routinely under continuous sedation for several hours after cea in the icu . anti - hypertensive treatment consisted of intravenous labetalol ( first choice ) continuous infusion and/or bolus infusion . if bp was not controlled , oral clonidine was added . if bp was within the required limits , intravenous anti - hypertensive treatment was tapered as soon as possible and an oral beta - blocker ( labetalol or metoprolol ) was started . when chs was detected , postoperative systemic bp was more stringently controlled to maintain it below 120/80 mm hg . the cerebral perfusion state was routinely evaluated by pct at postoperative 2 days and tcd at postoperative 0 , 2 , and 7 days after cea or on detecting chs . the patient population consisted of 12 men and 4 women ranging in age from 59 to 81 years ( meanstandard deviation , 70.46.4 years ) . severity of ipsilateral internal carotid artery ( ica ) stenosis was ranged from 60% to 99% ( meanstandard deviation , 79.412.2% ) . comorbidities associated with carotid disease , such as hypertension ( 75.0% ) and diabetes mellitus ( 50.0% ) , were common among the patients . the indications for cea were asymptomatic ica stenosis ( 4 patients , 25.0% ) , recent minor stroke ( 7 patients , 43.8% ) , and tia ( 5 patients , 31.3% ) . tia presented as hemiparesis in 3 patients , amaurosis fugax in 1 patient , and hemiparesthesia in 1 patient . post - cea vmean change on the mca territory by the tcd was shown in fig . 2 . among 16 patients , 2 patients ( 12.5% ) developed post - cea hyperperfusion by the tcd . one patient was a 68-year - old man and had a history of transient left hemiparesis . post - cea hyperperfusion was detected by the tcd on the second postoperative day and was normalized on the seventh postoperative day . these 2 patients had uneventful postoperative courses and did not developed clinical chs for one month after cea . post - cea mean rcbf change on the aca territory was measured by pct in fig . the mean rcbf on the ipsilateral side increased from 45.3 to 70.1 ml/100 g / min after cea , which has a statistical significance ( p=0.049 ) . the mean rcbf on the contralateral side increased from 50.3 to 70.1 ml/100 g / min after cea ( p=0.221 ) . php was observed in 3 cases ( 18.7% ) on the pct result of the 16 patients . among 3 patients , 68-year - old and 76-year - old men who also showed php by the tcd presented cbf increment as 183.5% and 150.8% , respectively . almost all studies suggested that strict bp control was the most important and was a mainstay of post - cea management7,9,18,23,25,27,34 ) . however , we do not know how to best manage the patients underwent cea : the targets for blood pressure levels after cea ( to prevent postoperative ischemic stroke risk and at the same time avoid cerebral hyperperfusion ) are not well defined7,28 ) . the meta - analysis study reported that there is no published case of chs below systolic bp of 135 mm hg5 ) . in the literature review , 2 studies used a guideline as systolic bp < 160 mm hg and showed 5.0% of chs in table 219,25 ) . three studies complied with bp guideline as systolic bp < 140 mm hg and systolic bp was more stringently controlled to lower than 120 mm hg when post - cea hyperperfusion was detected1,13,33 ) . our study also complied with this bp guideline and accomplished 0% of chs . in order to control increased bp , one book suggested that nicardipine ( calcium antagonists ) was the agent of choice8 ) . however , van mook et al.34 ) insisted that many drugs commonly used for treatment of hypertension such as calcium antagonists and direct vasodilators ( for example , nitroprusside or glycerol trinitrate ) are contraindicated on theoretical ground . efficacy and safety of other medications are need to further studies . in terms of postoperative care at an icu , the current american heart association guidelines4 ) for cea state that patients who undergo cea should use icu resources as recommended in major surgical texts . we continuously monitored and controlled bp immediately using intravenous beta blockers for 2 days after cea in the icu , followed by oral or intravenous antihypertensive medications in a general ward . icu care can also offer that medical attendees are checking the chs under constant surveillance . first , the present investigation was retrospective and not fully controlled , as other medications , including antiplatelet therapy or anticoagulants , were occasionally used . second , the cbfs in this study were analyzed according to the classic region of interest ( roi ) method , in which rois are drawn manually as a way to solve visual assessment . however , this method has been shown to suffer from significant intra - observer and inter - observer variation16 ) . however , single - photon emission computed tomography was not available in our institute during the study period and this study could not contain the result . intensive care with strict bp control ( < 140/90 mm hg ) achieved a low prevalence of post - cea hyperperfusion and prevented post - cea chs . this study suggests that intensive care with strict bp control can prevent the prevalence of post - cea chs .
objectivecerebral hyperperfusion syndrome ( chs ) is a serious complication after carotid endarterectomy ( cea ) . 
 however , the prevalence of chs has decreased as techniques have improved . 
 this study evaluates the role of strict blood pressure ( bp ) control for the prevention of chs.methodsall 18 patients who received cea from february 2009 through november 2012 were retrospectively reviewed . 
 all patients were routinely managed in an intensive care unit by a same protocol . 
 the cerebral perfusion state was evaluated on the basis of the regional cerebral blood flow ( rcbf ) study by perfusion computed tomography ( pct ) and mean velocity by transcranial doppler ( tcd ) . 
 bp was strictly controlled ( < 140/90 mm hg ) for 7 days . when either post - cea hyperperfusion ( > 100% increase in the rcbf by pct or in the mean velocity by tcd compared with preoperative values ) or chs was detected , bp was maintained below 120/80 mm hg.resultstcd and pct data on the patients 
 were analyzed . 
 ipsilateral rcbf was significantly increased after cea in the pct ( p=0.049 ) . 
 post - cea hyperperfusion was observed in 3 patients ( 18.7% ) in the pct and 2 patients ( 12.5% ) in the tcd study . 
 no patients developed clinical chs for one month after cea . 
 furthermore , no patients developed additional neurological deficits related to postoperative cerebrovascular complications.conclusionintensive care with strict bp control ( < 140/90 mm hg ) achieved a low prevalence of post - cea hyperperfusion and prevented chs . 
 this study suggests that intensive care with strict bp control can prevent the prevalence of post - cea chs .