Ischemic Stunning of the Brain

Abstract

Background and Purpose-Early arterial recanalization (ER) with intravenous tissue plasminogen activator (tPA) can lead to dramatic clinical recovery, whereas some patients do not experience immediate clinical improvement. Methods-Consecutive patients received tPA 0.9 mg/kg IV within 3 hours after symptom onset. All had M1 or M2 middle cerebral artery occlusions on pretreatment transcranial Doppler. Patients were continuously monitored for 2 hours after bolus. ER was defined as the Thrombolysis in Brain Ischemia intracranial flow increase by Ն1 grade. Stroke severity (National Institutes of Health Stroke Scale [NIHSS]) and recovery (modified Rankin Scale) were assessed independently of transcranial Doppler. Results-One hundred twenty patients (mean age, 68Ϯ15 years; 63 women; median NIHSS, 17; range, 5 to 29; 90% with Ն10 points) received tPA at a median of 120 minutes, 50% within the first 2 hours. ER was observed in 73 patients (32 complete, 41 partial). No immediate clinical changes (nϭ23) or worsening (by 1 to 6 points on NIHSS, nϭ4) was observed in 37% of ERs (nonresponders). Complete ER was found in 8 of these 27 patients. At 24 hours, 22 of 27 patients (82%) had persisting deficits of NIHSS Ն10 points, yet 37% of these nonresponders (10 of 27) still achieved good outcome (modified Rankin score, 0 to 2) at 3 months. Among nonresponders with good outcome, 100% had detectable residual flow signals, and 70% had compensatory flow diversion on prebolus transcranial Doppler compared with 65% and 29% of nonresponders with poor outcome (PϽ0.05). Compared with responders (nϭ46), nonresponders had similar prebolus median NIHSS of 16 to 17 points, bolus times of 120 to 132 minutes, median speed of thrombolysis (30 minutes), and ER times of 190 to 193 minutes after onset. Reocclusion occurred in 3 of 4 patients with clinical worsening, 30% of other nonresponders, and 22% of responders. Symptomatic hemorrhage rate was 4% in both groups. At 3 months, mortality was 33% in nonresponders compared with 9% in responders (Pϭ0.001). Conclusions-After successful arterial ER with tPA therapy, lack of early clinical changes or worsening is relatively common (37%) and appears to be independent of time to tPA bolus or reperfusion. However, with tPA alone, at least one third of these nonresponders still achieved good outcomes at 3 months, suggesting the possibility of a "stunned brain" syndrome with delayed recovery. Several different mechanisms may potentially account for this phenomenon.

Stroke Recovery Genetics

“…7,8 But predictive models based on clinical factors remain limited by imprecision and difficulty with translation to the individual case. 9 This may improve when mechanisms such as brain plasticity 10 and brain stunning 11 and factors that influence these concepts become better defined.…”

Microbubble-Mediated Sonothrombolysis Improves Outcome After Thrombotic Microembolism-Induced Acute Ischemic Stroke

“…1 One important reason for this failure might be microcirculation no-reflow, a phenomenon in which major vessel recanalization does not result in adequate microvascular reperfusion. [2][3][4][5] Microthrombi, originating from upstream clot fragmentation or formed in situ, have been shown to play pivotal roles in the development of the no-reflow phenomenon.…”

Dramatic Recovery in Acute Ischemic Stroke Is Associated With Arterial Recanalization Grade and Speed

“…Although recanalization is a critical factor for favorable clinical outcome, 3 lack of early clinical improvement is common after recanalization. 4,5 Additional evidence is needed to understand the role, if any, of recanalization on DR.…”