Natural history of the spontaneous reperfusion of human cerebralinfarcts as assessed by 99mTc HMPAO SPECT

摘要

OBJECTIVE—Little is known about the effect of spontaneous reperfusion of human cerebral infarcts. Single photon emission computerised tomography (SPECT) data were analysed from a study using ⁹⁹Tc^m HMPAO (⁹⁹Tc^m hexamethylpropyleneamine oxime) in human cerebral infarction for the frequency of reperfusion and to see if it affected infarct size, oedema, haemorrhagic transformation, or functional outcome.
METHODS—Fifty sequential cases of ischaemic stroke were studied with 124 ⁹⁹Tc^m HMPAO SPECT at around one day, one week, and three months after stroke along with detailed clinical and functional assessments.
RESULTS—Visually apparent reperfusion occurred in 14 of 50 patients (28%) with a mean delay of 5.8 days and reperfusion was seen in seven others in whom it was identified on the basis of changes in perfusion deficit volume. It occurred in 13 of 23 embolic events but only in three of 23 other events. In only two cases did spontaneous reperfusion occur early enough to preserve tissue or function. Reperfusion did not otherwise reduce infarct size, or improve clinical or functional outcome, and was not associated with oedema butan association with haemorrhagic transformation was suggested. Reperfusion significantly decreased the apparent perfusion defect asmeasured by SPECT one week from the ictus, but was mostlynon-nutritional and transient. The mean volume of tissue preserved bynutritional reperfusion was 10 cm³, but this was unequallydistributed between cases. Late washout of⁹⁹Tc^m HMPAO from areas of hyperaemicreperfusion may be a good prognostic marker but is a rare phenomenonand too insensitive to be of general applicability.
CONCLUSIONS—Spontaneous reperfusion after cerebralinfarction occurs in 42% of cases within the first week but isassociated with clinical improvement in only 2%. It has few adverseconsequences although it may be associated with haemorrhagic transformation.