Background and purpose: The rationale behind thrombolytic therapy in acute ischemic stroke is penumbral salvage by rapid restoration of cerebral blood flow. The relationship, however, between early reperfusion (potentially composed of both nutritional and nonnutritional components) and outcome remains unclear.
Methods: To establish the relationship between reperfusion parameters and outcome variables (Canadian Neurological Scale, Barthel Index, outcome CT scans), we used 99Tc-hexamethylpropyleneamine oxime (99Tc-HMPAO) single-photon emission CT (SPECT) to examine 41 acute ischemic stroke patients. All patients had at least 2 SPECT studies (24 with 3 studies), and none had been treated with thrombolytic or other acute investigational drugs.
Results: A total of 106 studies were performed. Mean time to acute study was 9.2 hours; that for subacute study was 42 hours and for outcome study was 150 days. Hypoperfusion (HP) volumes at each of the 3 time points correlated with outcome clinical state and final infarct size. Both early reperfusion (61% of patients) and nutritional reperfusion alone (56%), which is early reperfusion maintained at outcome, were associated with improvement in clinical state and better functional outcome. Early HP volume change (acute minus subacute HP volume) and total HP volume change (acute minus outcome HP volume) also correlated with clinical improvement and better outcome.
Conclusions: This study establishes the benefit of spontaneous reperfusion after ischemic stroke and emphasizes the prognostic value of HP deficit volumes. 99Tc-HMPAO SPECT may be used to screen patients and group them according to perfusion deficit in acute stroke trials, thereby decreasing patient numbers required to show drug effect.