Aneurysmal subarachnoid hemorrhage (SAH) presents at a mean age of 55 years and affected patients are more likely to be Black, female, or tobacco users or have hypertension. Although patients rarely have a family history of cerebral aneurysm, two or more first-degree relatives with the condition confers a 12% prevalence of cerebral aneurysm. The American Heart Association (AHA) and American Stroke Association (ASA) released guidelines for the management of patients with aneurysmal SAH.

DIAGNOSING ANEURYSMAL SAH

Classically, aneurysmal SAH presents with sudden-onset headache that immediately reaches its maximum intensity. Warning or sentinel headaches precede up to 43% of these hemorrhages. Aneurysmal SAH can be ruled out in alert patients 15 years or older with sudden-onset nontraumatic headache that reaches maximum intensity within 1 hour, and who have none of the signs or symptoms listed in the Ottawa SAH rule: age 40 years or older, neck pain or stiffness, witnessed loss of consciousness, onset during exertion, thunderclap headache, or limited neck flexion on examination.

All other patients should receive noncontrast computed tomography (CT) of the head, which, if obtained within 6 hours of onset, has 99% sensitivity and can rule out aneurysmal SAH. Lumbar puncture is recommended after 6 hours of symptom onset.

Patients with positive noncontrast CT results should undergo CT angiography unless the hemorrhage visible on CT is diffuse, in which case digital subtraction angiography provides better resolution.

EARLY TREATMENT

Hospital Systems of Care

Most observational studies suggest that treatment of aneurysmal SAH at centers that treat more than 35 cases per year have superior outcomes. Stroke center designation is associated with lower in-hospital mortality for aneurysmal SAH.

Medical Treatment to Prevent Rebleeding

Blood pressure variability worsens outcomes in aneurysmal SAH and severe hypertension and relative hypotension should be avoided. Systolic blood pressure should be maintained at 160 mm Hg or less.

Reducing bleeding risk may not be beneficial once aneurysmal SAH is diagnosed. Treatment of bleeding with tranexamic acid does not reduce rebleeding or improve functional outcomes. Emergency anticoagulation reversal has not been studied in aneurysmal SAH, although it has been shown to be beneficial in other forms of intracerebral hemorrhage.

Aneurysm Repair

Aneurysm repair within the first 24 hours is recommended, unless the prognosis is very poor. Severe aneurysmal SAH, defined as a grade 4 or 5 on the Hunt and Hess or World Federation of Neurosurgical Societies scale, has a favorable outcome with treatment in 40% of patients. Although older patients tend to have worse outcomes after aneurysmal SAH, 42% of patients older than 65 years reach functional independence after treatment. Treatment is not recommended for patients who have partial loss of brainstem reflexes, lack of purposeful response to noxious stimuli, or imaging showing a large completed ischemic infarct or the global cerebral edema of anoxic brain injury.

Patient-specific factors can suggest open surgical or endovascular repair, although few objective data exist. Surgical clipping improves mortality and patient independence compared with conservative treatment. Functional independence may be more likely with endovascular coiling at 1 year, but there is no benefit at 5 years. Complete aneurysm obliteration results in lower risk of rebleeding, and retreatment in 1 to 3 months is recommended if only partial treatment for the aneurysm can be completed.

Recurrent aneurysmal SAH affects 2% of patients after endovascular coiling and 0.6% of patients after surgical clipping within the first 30 days, with similar long-term risk. Surgical clipping is recommended for younger patients to reduce recurrence.

PREVENTING AND DETECTING COMPLICATIONS

Lung Injury

Nearly 4% of patients with aneurysmal SAH develop acute respiratory distress syndrome. Bundled care with lung-protective ventilation strategies, early enteral nutrition, systematic early extubation, and early hospital-acquired pneumonia treatment reduces this risk.

Hyponatremia and Fluid Status

Hyponatremia is common after aneurysmal SAH, which may increase delayed cerebral ischemia. Fludrocortisone is recommended for hyponatremia, although improvement in delayed cerebral ischemia is uncertain. High-dose hydrocortisone increases complications.

Fluids should be provided to maintain euvolemia because more than one-half of patients with volume depletion develop delayed cerebral ischemia. Hypervolemia should be avoided because it increases complications without improving outcomes.

Venous Thromboembolism Prevention

Venous thromboembolism can occur in 4% to 24% of patients with aneurysmal SAH. Pharmacologic or mechanical venous thromboembolism prophylaxis is recommended in patients after the aneurysm has been treated, although the optimal timing for prophylaxis is unclear.

Hyperglycemia

Hyperglycemia within 72 hours of aneurysmal SAH increases delayed cerebral ischemia and death. Limited studies suggest conventional glycemic control is as effective as intensive control.

Fever

Although fever is common after aneurysmal SAH and can lead to worse outcomes, the benefit of fever treatment and therapeutic hypothermia is uncertain.

Neurologic Deficits

In one study, 72 hours of frequent neurologic monitoring with the Glasgow Coma Scale and the National Institutes of Health Stroke Scale demonstrated neurologic deterioration in 43% of patients. Neurogenic dysphagia affects up to 65% of patients after stroke, and nurse-initiated dysphagia screening reduces pneumonia and mortality.

Nurse-driven early mobilization after aneurysmal SAH reduces severe vasospasm, a cause of delayed cerebral ischemia, and improves function.

Seizures

Seizures affect up to 15% of patients after aneurysmal SAH and are less common after endovascular coiling than surgical clipping. In addition to convulsions, seizures can present with depressed consciousness or fluctuating neurologic examination findings.

Following a seizure, continuing anticonvulsants for up to 7 days is reasonable. Prophylactic anticonvulsants should be considered for patients with high-grade aneurysmal SAH, hydrocephalus, cortical infarction, intracranial hemorrhage, or middle cerebral artery aneurysm.

Delayed Cerebral Ischemia

Delayed cerebral ischemia affects 30% of patients and occurs between days 4 and 14 after aneurysmal SAH. A 2-point decrease in Glasgow Coma Scale score over 1 hour demonstrates delayed cerebral ischemia. CT perfusion studies performed 3 days after aneurysmal SAH can predict delayed cerebral ischemia with 67% positive predictive value.

CT arteriography demonstrates cerebral vasospasm related to delayed cerebral ischemia with 91% sensitivity. Transcranial Doppler ultrasonography can screen for middle cerebral artery vasospasm with 90% sensitivity and 92% negative predictive value. Continuous electroencephalography monitoring can suggest injury because alarms occur in 96% of patients with delayed cerebral ischemia and 20% of patients without.

Early initiation of nimodipine reduces delayed cerebral ischemia. Vasopressor therapy appears to improve functional outcomes after aneurysmal SAH.

For patients with cerebral vasospasm, intra-arterial vasodilator administration may improve outcomes if systemic hypotension and elevated intracerebral pressure are avoided. Angioplasty can stop vasospasm but increases cerebral infarction risk. Statin therapy and magnesium sulfate are not beneficial.

Hydrocephalus

Hydrocephalus affects up to 87% of patients after aneurysmal SAH. Lumbar drainage of cerebrospinal fluid can reduce delayed cerebral ischemia caused by hydrocephalus.

RECOVERY

In addition to neurologic limitations, cognitive impairments and psychological comorbidities are common after aneurysmal SAH.

Short-Term Issues

Early functional rehabilitation appears safe after aneurysmal SAH, although the benefits are uncertain. For unconscious patients, neurostimulants (e.g., amantadine, modafinil) may be helpful in improving consciousness and functional outcomes.

Cognitive impairments affect one-fourth of patients with good functional outcomes, and are more common after hydro-cephalus, seizure, fever, prolonged intensive care, and delayed cerebral ischemia. Screening tools such as the Montreal Cognitive Assessment can be helpful in determining the need for cognitive rehabilitation.

Approximately one-third of stroke survivors have depression, anxiety, or posttraumatic stress disorder, therefore screening and treatment are recommended.

Long-Term Issues

Approximately one-half of patients experience cognitive deficits for a year after aneurysmal SAH. Patients with previous aneurysmal SAH have nearly triple the dementia risk as those without. In addition to psychological diagnoses, sexual dysfunction is also common and can affect quality of life.

Editor’s Note: This guideline on aneurysmal SAH is helpful in that it covers a relatively rare disease that we often worry about. The most important element of this guideline might be the Ottawa SAH rule, which can be used to rule out aneurysmal SAH. The Ottawa SAH rule had a 100% negative predictive value in a validation study of 5,000 patients, of which 454 were eligible for the rule.¹ The treatment details are most valuable in highlighting the importance of experienced stroke centers, especially because the evidence remains limited.

—Michael J. Arnold, MD, Assistant Medical Editor

1. Bellolio MF, Hess EP, Gilani WI, et al. External validation of the Ottawa subarachnoid hemorrhage clinical decision rule in patients with acute headache. Am J Emerg Med. 2015; 33(2): 244-249.

The views expressed are those of the author and do not necessarily reflect the official policy or position of the Naval Undersea Medical Institute, Uniformed Services University of the Health Sciences, U.S. Navy, U.S. Department of Defense, or U.S. government.

Guideline source: American College of Cardiology and American Heart Association

Published source: Hoh BL, Ko NU, Amin-Hanjani S, et al. 2023 Guideline for the management of patients with aneurysmal subarachnoid hemorrhage: a guideline from the American Heart Association/American Stroke Association [published correction appears in Stroke. 2023;54(12):e516]. Stroke. 2023;54(7):e314–e370.

Available at https://www-ahajournals-org.lib3.cgmh.org.tw:30443/doi/epub/10.1161/STR.0000000000000436