From the Guidelines
The target blood pressure after clipping a brain aneurysm in Subarachnoid Hemorrhage (SAH) is not explicitly defined, but guidelines recommend treating high blood pressure with a titratable agent to balance the risk of stroke, hypertension-related rebleeding, and maintenance of cerebral perfusion pressure.
Key Considerations
- The American Heart Association/American Stroke Association guidelines recommend treatment with a titratable agent if systolic BP exceeds 160 mm Hg 1.
- The European Stroke Organization guidelines recommend treatment if systolic BP exceeds 180 mm Hg, starting with analgesics and nimodipine, and continuing as necessary to maintain a mean arterial pressure of > 90 mm Hg 1.
- The goal is to balance the risk of rebleeding, which is associated with high blood pressure, and the risk of delayed cerebral ischemia (DCI), which may be increased by lowering blood pressure too aggressively 1.
Management Strategies
- Nicardipine may give smoother blood pressure control than labetalol and sodium nitroprusside, although data showing different clinical outcomes are lacking 1.
- Clevidipine, a very short-acting calcium channel blocker, is another option for acute control of hypertension, but data for aSAH are lacking at this time 1.
- Antifibrinolytic therapy has been shown to reduce the incidence of aneurysm rebleeding when there is a delay in aneurysm obliteration, but its use is not widely recommended due to the risk of deep venous thrombosis and other complications 1.
From the Research
Target Blood Pressure after Clipping a Brain Aneurysm in Subarachnoid Hemorrhage (SAH)
- The target blood pressure after clipping a brain aneurysm in SAH is not well established, with varying practices among clinicians 2, 3.
- A survey of Canadian intensivists and cerebrovascular neurosurgeons found that in the postsecured period, a systolic blood pressure of 180 mm Hg was the most frequently selected upper-limit target, but there was a wide distribution of targets selected across all three cases ranging from 100 to > 200 mm Hg 2.
- Another survey of physicians and advanced practitioner members of the Neurocritical Care Society found that after aneurysm treatment, systolic blood pressure limits ranged from 160 to 240 mm Hg 3.
- A study of blood pressure management goals in critically ill aneurysmal subarachnoid hemorrhage patients in Australia and New Zealand found that BP management goals were recorded in 266 of 357 (75%) patients, but the association between setting BP management goals and reduced death or disability was not significant after adjustment for the presence of delayed cerebral ischemia or vasospasm 4.
- A retrospective study of consecutive patients with aSAH admitted to an academic center found that higher mean arterial pressure (MAP) was associated with rebleeding and poor outcome, with an odds ratio of 1.02 for 1 mmHg increase in MAP 5.
- A review of the literature on management of blood pressure in acute aneurysmal subarachnoid hemorrhage recommends avoiding large degrees of blood pressure variability and acute lowering of systolic blood pressure to a range of 140-160 mmHg to decrease the risk of rebleeding while maintaining cerebral perfusion pressure (CPP) 6.
Blood Pressure Parameters
- Systolic blood pressure (SBP) and mean arterial pressure (MAP) are the most commonly used blood pressure parameters in the management of SAH 2, 3, 5.
- MAP may be slightly better correlated with rebleeding and poor outcomes in unsecured aSAH compared to SBP 5.
- Elevations in intracranial pressure occur commonly after SAH, and clinicians should be familiar with changes in cerebral autoregulation and effects on CPP when treating elevated BP 6.