Delayed ischemia risk after SAH unaffected by rebleeding
MedWire News: The detrimental impact of rebleeding on outcomes in patients with subarachnoid hemorrhage (SAH) may be driven by an increased risk for general medical complications rather than delayed cerebral ischemia, research suggests.
Rebleeding is a known cause of increased mortality and morbidity in patients with SAH, often occurring within hours of the original bleed, before patients have undergone clipping or coiling of their aneurysms.
The authors of the current study, Neeraj Badjatia (Columbia University, New York, USA) and colleagues, say that although risk factors for rebleeding have been the subject of much study, it is not known by which mechanisms rebleeding harms patient outcomes.
One possibility is that rebleeding harms patients via specific neurologic mechanisms, most notably delayed cerebral ischemia, which is relatively common after SAH. But the team's study findings do not support such a hypothesis. The incidence of delayed cerebral ischemic was 29% among 120 SAH patients with rebleeding (cases) and 27% among 359 patients without rebleeding (controls), who were matched to those with rebleeding by age, gender, modified Fisher scale, and Hunt-Hess grade.
Rebleeding did not affect the time to delayed ischemia, which was an average of 7 days in both groups. In a secondary analysis of patients who survived for at least 7 days after the initial SAH (the highest-risk period for delayed ischemia), 39% versus 31% of cases and controls had delayed cerebral ischemia. This difference was not significantly different and, again, the average time to delayed ischemia was 7 days in both groups.
By contrast, several medical complications were significantly more frequent among cases than controls, with hyponatremia occurring in 24% versus 13%, hydrocephalus in 75% versus 53%, and intubation required in 90% versus 69%.
"Each of these measures may be a reflection of the increased injury severity incurred as a result of rebleeding," comment Badjatia et al in the journal Neurology.
These complications were significantly associated with rebleeding on multivariate analysis. Among patients surviving to day 7, rebleeding was associated with hyponatremia, hydrocephalus, and fever.
"With increasingly strong evidence that early administration of an antifibrinolytic agent prevents rebleeding with minimal life-threatening complications, this report lends strength to the need for further study and promotion of this potentially life-saving therapy," concludes the team.
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By Eleanor McDermid