delayed acute subdural hematoma ( dash ) is a subdural hematoma which is detected later . an initial computed tomography ( ct ) does not reveal any intracranial hemorrhage at all . few patients of dash after mild traumatic brain injury associated with percutaneous coronary intervention ( pci ) have been published . a 63-year - old woman presented with cardiac pulmonary arrest due to acute myocardial infarction and lethal arrhythmia . however , 1 hour after pci , she lost consciousness and immediate ct showed acute subdural hematoma and subarachnoid hemorrhage . the period from losing consciousness to brain herniation presenting as anisocoria was very short  only 30 minutes in our patient . although emergent evacuation of hematoma and external decompression were performed , the patient died 1 day after the operation . clinicians should be aware that subdural hemorrhage can occur after pci if no hemorrhage is noted in the initial head ct , and the operation should be performed as soon as possible when the consciousness level decreases . some pedestrians overlooked this fact and verified her cpa . before arrival of rescue workers , when rescue workers examined her in an ambulance , she was alert and oriented to time , place , and person . , whole body ct was performed to detect other injured sites including the head and to rule out pulmonary embolism and aorta dissection . computed plain old balloon atherectomy was performed , and a drug - eluting stent was implanted in the lesion . furthermore , 5000 units of unfractionated heparin were administered in the emergency room , and an additional 5000 units were administered at the beginning of the procedure . the activated clotting time was not estimated during the procedure because the coronary angiography was completed in a short duration and the amount of a heparin was considered to be adequate . after the procedure , she was oriented to time , place , and person and could communicate with her family members . however , 1 hour after pci , her consciousness decreased and she went into coma . emergency follow - up head ct revealed a massive subarachnoid hemorrhage and right acute subdural hematoma ( fig . it is noted that only 30 minutes was taken from her consciousness - level down to brain herniation which presented as anisocoria . emergency hematoma evacuation and external decompression were performed . however , intraoperatively , the whole brain looked severely pale and no longer pulsated . computed tomography performed 1.5  hours after percutaneous coronary intervention revealed massive subarachnoid hemorrhage and acute subdural hematoma . universally , mild tbi is defined by the following criteria : initial glasgow coma scale score of 13 through 15 , loss of consciousness of < 20 minutes , absence of focal neurological deficits , and post - traumatic amnesia of < 24  hours . mild tbi is very frequent in clinical practice and accounts for 80% of all patients of hospital admissions due to head injuries . in most patients , patients with mild tbi are permitted to go home if no lesion is detected in the head ct . however , some patients exacerbate and need surgical treatment . in almost all such patients , however , patients of delayed acute subdural hematoma are uncommon . delayed acute subdural hematoma , first described by cohen and gudeman , is defined as an acute subdural hematoma ( asdh ) that is not apparent on the initial ct scan , but appears on a follow - up ct scan . delayed acute subdural hematoma can occur in about 0.5% of asdh patients treated with surgery at the hospital . delayed acute subdural hematoma patients have rarely been discussed in detail , and only 7 previous patients have been published thus far . patient 1 was not examined using ct but cerebral angiography , which did not reveal any abnormalities . the time interval to the following ct scan ranges from 9  hours to 72  hours . the prognosis is almost poor ( 5 deaths and 2 in disability ) except for patient 7 ( good recovery ) . itshayek et al considered the administration of anticoagulants to elderly patients as a risk factor for dash . our patient was considered to be closely related to pci , which is a very effective and established procedure to treat coronary lesions . conversely , some common complications such as peripheral embolism , acute coronary occlusion , or puncture side related complications can occur . the anticoagulant heparin is imperative to avoid embolic complications and thrombosis . in this patient , we administered 10,000 units of heparin in total , which was an appropriate amount considering her weight . as reported in the study above , anticoagulant use seems to be related to dash . however , at least clinicians should explain this complication to the patients and their family prior to the procedure and recognize it as soon as possible . first , owing to hypotension , the intracranial hemorrhage was so tiny that it could not be detected on the initial ct . therefore , when a patient 's blood pressure increases , some bleeding appears in the cranium . other mechanisms such as vasoparalysis resulting from local hypoxia or local metabolic disorders that may injure the vessel wall have also been suggested . it is possible that the initial intracranial hemorrhage was so tiny owing to the absence of circulation . in addition to this , antithrombus agent use probably resulted in increasing the size of the hemorrhage , which caused brain herniation . a notable thing in this patient is the very short duration in which brain herniation developed . the interval from coma onset to brain herniation was far shorter than that from tbi to coma onset . we encountered a patient of dash following successful pci 9.5  hours after mild tbi . however , delayed new acute subdural hematoma and subarachnoid hemorrhage was detected . and it took only 30 minutes for brain herniation to occur after the appearance of coma . clinicians should be aware that dash can occur after pci , especially in cpa recover patients . the operation should be performed as soon as possible when dash - related pci occurs because of its exacerbation - period shortness .
background : delayed acute subdural hematoma ( dash ) is a subdural hematoma which is detected later . 
 an initial computed tomography ( ct ) does not reveal any intracranial hemorrhage at all . 
 few patients of dash after mild traumatic brain injury associated with percutaneous coronary intervention ( pci ) have been published.patient presentation : a 63-year - old woman presented with cardiac pulmonary arrest due to acute myocardial infarction and lethal arrhythmia . 
 she had hit her head on the road . 
 the initial ct did not reveal any hemorrhage in the intra - cranium . 
 she fully recovered after pci . 
 however , 1 hour after pci , she lost consciousness and immediate ct showed acute subdural hematoma and subarachnoid hemorrhage . 
 the period from losing consciousness to brain herniation presenting as anisocoria was very short  only 30 minutes in our patient . 
 although emergent evacuation of hematoma and external decompression were performed , the patient died 1 day after the operation.conclusion:the authors encountered a patient of dash after pci that resulted in death . 
 clinicians should be aware that subdural hemorrhage can occur after pci if no hemorrhage is noted in the initial head ct , and the operation should be performed as soon as possible when the consciousness level decreases .