Whether treating serum glucose to less than 140 mg/dL at admission can improve outcomes is a key area for future research, authors of a new study say.
Patients with acute ischemic strokes caused by large-vessel occlusions who are treated with mechanical thrombectomy fare worse over the first 3 months if they have hyperglycemia at the time of hospital admission, an observational study shows.
A serum glucose level above 140 mg/dL was associated with a lower likelihood of having functional improvement and a greater likelihood of dying over that span, Nitin Goyal, MD (University of Tennessee Health Sciences Center, Memphis), and colleagues report in a study published online March 13, 2017, in the Journal of NeuroInterventional Surgery.
“These findings emphasize the importance of careful management of serum glucose before, during, and after endovascular reperfusion therapies in [acute ischemic stroke] patients with proximal intracranial occlusions,” they write.
Prior studies have shown that hyperglycemia is common in patients admitted with acute ischemic stroke and that elevated serum glucose levels are related to worsened outcomes in those treated with IV thrombolytics.
To explore the issue in the context of mechanical thrombectomy, the researchers looked at data from 231 patients (mean age 62 years; 51% men) with imaging-confirmed large-vessel occlusions treated at three tertiary stroke centers. The median National Institutes of Health Stroke Scale score at admission was 16. More than one-third of patients (38%) had hyperglycemia.
The most common technique used for thrombectomy was a combination of distal aspiration and a stent retriever (53%), followed by a direct aspiration first pass technique (23%) and a stent retriever alone (15%). Acute angioplasty and/or stenting were used for the remaining cases. Most patients (63%) received systemic thrombolysis before thrombectomy. The interventions resulted in successful reperfusion (TICI 2b/3) in 67% of patients.
After accounting for potential confounders, admission hyperglycemia was associated with a lower likelihood of functional improvement—based on the distribution of modified Rankin Scale scores—at 3 months (common OR 0.53; 95% CI 0.31-0.97) and higher odds of 3-month mortality (OR 2.76; 95% CI 1.40-5.44). Relationships with symptomatic intracranial hemorrhage and functional independence (mRS score 0 to 2) were not significant, however.
Moreover, each 10-mg/dL increase in admission serum glucose was associated with progressively greater likelihood of symptomatic intracranial hemorrhage (OR 1.07; 95% CI 1.01-1.13) and 3-month mortality (OR 1.07; 95% CI 1.02-1.12).
Neither hyperglycemia nor serum glucose level were related to complete reperfusion or good collateral status.
“Hyperglycemia has been shown to exacerbate brain injury by enhancement of intracellular acidosis in ischemic penumbra, which in turn leads to mitochondrial dysfunction and energy failure,” the authors explain. “In addition, hyperglycemia can also impair cerebral autoregulation, predisposing to reperfusion injury and potential hemorrhagic transformation of infarcts treated with tissue plasminogen activator (tPA). Moreover, hyperglycemia has been linked to exacerbation of ischemic brain injury through free radical formation and worsening of cerebral edema through matrix metalloproteinase 9 activation.”
But despite plausible explanations for the link between hyperglycemia and poor outcomes, the observational design of the current study precludes any conclusions about causation, they say. “Whether the impact of hyperglycemia can be attenuated with admission treatment to < 140 mg/dL remains unknown, although this is an important area for future investigation, and methods will need to be incorporated into the current time-sensitive paradigm for rapid [mechanical thrombectomy] treatment.”
Sources:
Goyal N, Tsivgoulis G, Pandhi A, et al. Admission hyperglycemia and outcomes in large vessel occlusion strokes treated with mechanical thrombectomy. J NeuroIntervent Surg. 2017;Epub ahead of print.
Disclosures:
Goyal reports no relevant conflicts of interest.
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