Natural course of total mismatch and predictors for tissue infarction

OBJECTIVE:We longitudinally assessed patients presenting with total mismatch and hypothesized that hypoperfusion intensity ratio (HIR), severity of stroke, and occlusion of blood vessel are predictors of tissue fate. METHODS:Patients with suspected stroke or TIA admitted to our emergency department between September 2008 and October 2012 with suspected stroke or TIA were eligible to participate in the ongoing stroke imaging study 1000Plus. Patients received acute and follow-up stroke MRI, basic demographics were collected, and stroke severity was rated according to the NIH Stroke Scale (NIHSS). Inclusion criteria for the substudy were total mismatch on admission examination and available follow-up. RESULTS:We identified 23 patients with total mismatchmedian age 70 years (interquartile range 66–78), 10 female (43.5%). Infarction was found on follow-up diffusion-weighted imaging (median lesion size 1.3 mL) in 9 patients (39.1%). Infarction was correlated with NIHSS at admission (p = 0.026) and HIR (p = 0.015) but not with vessel occlusion. Clinical outcome as measured by last recorded NIHSS score and modified Rankin Scale score at discharge was significantly worse in patients with infarction on follow-up. CONCLUSION:Final infarction is frequently seen in patients with total mismatch. Clinical presentation at admission and severity of hypoperfusion measured by HIR, but not occlusion of the supplying vessel, predict tissue fate.