Medical Care
Prehospital care should include assessment of vital signs and neurological status. Airway, breathing, and circulation should be addressed with endotracheal intubation, if necessary, and establishment of intravenous access.
Medical therapy of cerebral aneurysms involves general supportive measures and prevention of complications for individuals who are in the periprocedural period or are poor surgical candidates. Treatment decisions should be based on the clinical status of the patient, vascular anatomy of the aneurysm, and surgical or endovascular considerations.
Medical management of aneurysmal SAH is orchestrated in the ICU, with cardiac monitoring and placement of an arterial line.
Prior to definitive aneurysm treatment, medical approaches involve control of hypertension, administration of calcium channel blockers, and prevention of seizures.
Following surgical or endovascular aneurysm treatment, blood pressure is maintained at higher levels to diminish complications associated with vasospasm. Vasospasm usually occurs between days 3 and 21, presenting with headache, decreased level of consciousness, and variable neurological deficits. Serial TCD may be employed to detect trends in cerebral blood flow during this period.
Induced hypertension, hypervolemia, and hemodilution (ie, "triple-H therapy") aimed to maintain adequate cerebral perfusion pressure in the setting of impaired cerebrovascular autoregulation. However, guidelines have moved toward maintenance of euvolemia and induced hypertension based on recent literature. [9]
Intraarterial papaverine or endovascular balloon angioplasty may be used to treat vasospasm in select patients.
Infectious aneurysms are friable, with an increased propensity for hemorrhage. Anticoagulation is avoided in this setting. As these lesions resolve with antibiotic therapy, surgical approaches usually are deferred. Regression or evolution of these aneurysms is monitored with serial angiography.
Unruptured Intracranial Aneurysms
The management of unruptured intracranial aneurysms is highly controversial. The International Study of Unruptured Intracranial Aneurysms (ISUIA) indicated a relatively low risk of rupture in small aneurysms without history of SAH. Aneurysms less than 10 mm in size had an annual rupture rate of approximately 0.05%. For posterior communicating, vertebrobasilar/posterior cerebral, or basilar tip aneurysms less than 10 mm, the risk of rupture over 7.5 years approximated 2%, with all other locations harboring a risk of almost 0%. Recent guidelines and an evidence-based systematic review of the literature have formulated recommendations for the care of patients with unruptured intracranial aneurysms, principally based on age, history, and aneurysm size.
The anatomical characterization and morphology of unruptured aneurysms are not readily standardized, however. Some investigators have advocated endovascular or surgical treatment of all aneurysms less than 10 mm if age is less than 50 years, in the absence of contraindications. The presence of cigarette smoking, family history of aneurysms, polycystic kidney disease, or systemic lupus erythematosus may elevate the risk of rupture and should be considered. Asymptomatic aneurysms greater than 10 mm should also be considered for treatment, accounting for age, coexisting medical conditions, and relative risks for treatment.
Considerable surgical mortality and morbidity rates at 1 year (as high as 3.8% and 15.7%, respectively) have been demonstrated in preventive treatment of unruptured aneurysms. The surgeon's experience may be a significant and highly variable factor in operative morbidity rate and functional outcome. More recently, application of diffusion-weighted MRI has demonstrated silent thromboembolic events associated with endovascular treatment of unruptured cerebral aneurysms. Quality-of-life issues, including the psychological morbidity of living with an unruptured intracranial aneurysm, also must be addressed.
Therapeutic decision making must balance endovascular or surgical morbidity and mortality rates with the risk of hemorrhage and other considerations on an individual basis. Future studies in the management of unruptured intracranial aneurysms may systematically account for the evolving technology of advanced endovascular approaches, detailed aneurysm morphology, novel neuroimaging correlates, ethnic and geographical variation, neurocognitive impairment following endovascular or surgical treatment, and quality-of-life issues.
Surgical Therapy
Microsurgical techniques focus on excluding the aneurysm from the cerebral circulation and reducing mass effects on adjacent structures. Various approaches have been developed and tailored to the anatomy and location of the aneurysm. A surgical clip usually is placed across the aneurysm neck with preservation of the parent vessel, eliminating any aneurysmal rests that may redevelop subsequently. Alternative techniques involve proximal or Hunterian ligation, wrapping the aneurysm, and trapping (ie, combined proximal and distal vessel occlusion).
Adjunctive measures have been developed to reduce operative morbidity and to provide cerebral protection. Aneurysmal rupture, the principal surgical complication, may be avoided with induced hypotension, CSF drainage, diuretics, hyperventilation, and use of minimal brain retraction. Hypothermia, with or without circulatory arrest, and systemic hypotension are used commonly. A large study of mild intraoperative hypothermia, however, failed to demonstrate benefit of this adjunctive technique.
Lumbar spinal drainage allows relaxation of brain parenchyma and provides a clean surgical field. Postoperative angiography is performed routinely to check for major vessel occlusion or persistence of an aneurysmal rest. Operative morbidity rate increases with aneurysm size (2.3% for < 5 mm; 6.8% for 6-15 mm, 14% for 16-25 mm) and varies by location.
Optimal timing of aneurysm surgery depends on the clinical status of the patient and associated factors. Early surgery (ie, < 48-96 hours after SAH) is favored for candidates in good condition or those with unstable blood pressure, seizures, mass effect from thrombus, large amounts of blood, or evidence of aneurysm growth or rebleeding. Early surgery carries an increased operative morbidity, although the risks of vasospasm and rebleeding are reduced considerably.
Delayed surgery (ie, 10-14 d after SAH) may be considered for large aneurysms in difficult locations or for candidates in poor clinical condition. Surgery is indicated for ruptured or symptomatic aneurysms in patients without extenuating contraindications or considerably advanced age. Surgery generally is precluded if the clinical status is poor, corresponding to Hunt and Hess grade 4 or 5.
Endovascular Techniques
Advances in endovascular techniques have provided therapeutic alternatives that may be employed even in the setting of acute aneurysmal SAH. These techniques allow parent vessel preservation and may be combined with surgical approaches. Electrolytically detachable platinum coils (eg, Guglielmi detachable coils [GDC]) may be deployed strategically within the aneurysm, promoting thrombosis and eventual obliteration. Wide-neck aneurysms may be more difficult to occlude with these devices. Other materials, such as balloons or glue, also may be used. Complications include vessel perforation, hemorrhage, or distal thromboembolism.
Endovascular therapy or coiling of cerebral aneurysms has proliferated during the past of particular cerebral aneurysms are likely influenced by numerous factors. The International Subarachnoid Aneurysm Trial (ISAT) demonstrated the superiority of coiling with improved clinical outcomes. Seizures were also less common in patients with endovascular treatment, yet late rebleeding was also more common. Selection bias may also have influenced ISAT and, therefore, treatment for a given individual must still be tailored to each case.
A meta-analysis of relevant studies (including ISAT) found that endovascular coiling of cerebral aneurysms yields a better clinical outcome than clipping does, with the benefit greatest in patients with a good preoperative grade. [1, 2] The analysis also confirmed, however, that there is a greater risk of rebleeding with coiling, particularly for patients with a poor preoperative grade. Patient mortality at 1 year with coiling was not significantly different from 1-year mortality with clipping. [1, 2]
Progressive refinement in endovascular techniques and devices tailored for the cerebrovasculature have expanded therapeutic options available for definitive treatment of cerebral aneurysms. More pliable, low-profile stents may be used for stent-assisted coiling for obliteration of wide-necked aneurysms.
Self-expanding or balloon-expandable covered stents may be used for treatment of selected carotid or vertebral artery pseudoaneurysms. [10] The Silk flow-diverter stent allows complete occlusion in most cases after 1 year of treatment, with 7.8% permanent morbidity and 3% mortality. [11]
Large or giant intracranial aneurysms may be treated with a combination of devices, such as stent-assisted coil placement. [12] However, the requirement of dual antiplatelet therapy in stent-assisted coiling may increase the risk of intracranial hemorrhage. [13]
Refinement of endovascular techniques for very small intracranial aneurysms has expanded treatment options, yet complications may also increase in this particular subset. [14]
Although endovascular coiling is a feasible, effective treatment for many elderly patients with ruptured and unruptured intracranial aneurysms, careful patient selection is crucial in view of the risks of the procedure, which may outweigh the risk of rupture in some patients with unruptured aneurysms, according to a systematic review and meta-analysis that included 21 studies of 1511 patients aged 65 years or older. [15, 16]
In this study, long-term occlusion was achieved in 79% of patients. [16] The rate of perioperative stroke (4%) was similar for patients with unruptured and ruptured aneurysms. Intraprocedural rupture occurred in 1% of patients with unruptured aneurysms and in 4% of patients with ruptured aneurysms. Perioperative mortality was 23% for patients with ruptured aneurysms and 1% for those with unruptured aneurysms. At 1-year follow-up, 93% of patients with unruptured aneurysms and 66% of patients with ruptured aneurysms had good outcomes.
Consultations
A multidisciplinary approach to the treatment of cerebral aneurysms is recommended. The following specialists should be a part of the multidisciplinary team:
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Neurosurgeon
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Interventional neuroradiologist
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Neurologist
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Rehabilitation specialist
Diet
Restrict possible surgical candidates to taking nothing by mouth (NPO).
Employ nasogastric feedings for individuals with a decreased level of consciousness.
Recommend a soft, high-fiber diet to alert patients; patients should avoid caffeine.
Activity
Advise bed rest in a quiet dark environment during the initial week following aneurysmal SAH.
Perform passive range of motion exercises and frequent turning.
Assist patients with self-care activities, followed by slow advancement in activity as tolerated.
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Cerebral aneurysms. Volume-rendered CT angiography of a left middle cerebral artery aneurysm.
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Cerebral aneurysms. CT angiography of a right middle cerebral artery aneurysm.
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Cerebral aneurysms. Sagittal multiplanar reformatted view of a left internal carotid artery aneurysm.
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Cerebral aneurysms. Basilar tip aneurysm illustrated on CT scan (left) and T2-weighted MRI (right).
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Cerebral aneurysms. Volume-rendered CT angiography of a basilar tip aneurysm.
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Cerebral aneurysms. Aneurysm associated with an arteriovenous malformation (AVM) shown on T1-weighted MRI (left), 3D-time-of-flight MRI (middle), and conventional angiography (right).
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Cerebral aneurysms. Clipping vs coiling.
Tables
Grade |
Clinical Condition at Presentation |
0 |
Unruptured aneurysm |
1 |
Asymptomatic or minimal headache and slight nuchal rigidity |
2 |
Moderately severe or severe headache and nuchal rigidity; cranial neuropathy, no focal deficit |
3 |
Drowsiness, confusion, or mild focal deficit |
4 |
Stupor, moderate to severe hemiparesis |
5 |
Deep coma, decerebrate posturing, moribund appearance |
Grade |
Glasgow Coma Scale Score |
Clinical Findings |
I |
15 |
No headache or focal signs |
II |
15 |
Headache, nuchal rigidity, no focal signs |
III |
13-14 |
Headache, nuchal rigidity, no focal signs |
IV |
7-12 |
Headache, rigidity, focal signs |
V |
3-6 |
Headache, rigidity, focal signs |
Grade |
CT Findings |
1 |
No blood detected |
2 |
Diffuse thin layer of subarachnoid blood |
3 |
Localized thrombus or thick layer of subarachnoid blood |
4 |
Intracerebral or intraventricular hemorrhage with diffuse or no subarachnoid blood |
