Controversies in the Management of Aneurysmal Subarachnoid Hemorrhage*
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Controversies in the management of aneurysmal subarachnoid hemorrhage* Neeraj S. Naval, MD; Robert D. Stevens, MD; Marek A. Mirski, MD, PhD; Anish Bhardwaj, MD, FCCM Background: The care of patients with aneurysmal subarach- Data Source: Search of MEDLINE and Cochrane databases and noid hemorrhage has evolved significantly with the advent of new manual review of article bibliographies. diagnostic and therapeutic modalities. Although it is believed that Data Synthesis and Conclusions: Many aspects of care in these advances have contributed to improved outcomes, consid- patients with aneurysmal subarachnoid hemorrhage remain erable uncertainty persists regarding key areas of management. highly controversial and warrant further resolution with hypoth- Objective: To review selected controversies in the manage- esis-driven clinical or translational research. It is anticipated that ment of aneurysmal subarachnoid hemorrhage, with a special the rigorous evaluation and implementation of such data will emphasis on endovascular vs. surgical techniques for securing provide a basis for improvements in short- and long-term out- aneurysms, the diagnosis and therapy of cerebral vasospasm, comes. (Crit Care Med 2006; 34:511–524) neuroprotection, antithrombotic and anticonvulsant agents, cere- KEY WORDS: aneurysm; subarachnoid; hemorrhage; vasospasm; bral salt wasting, and myocardial dysfunction, and to suggest ischemia venues for further clinical investigation. he rupture of an intracranial sepsis, and thromboembolism. As many and management of cerebral vasospasm, aneurysm may be associated of these complications are life-threaten- neuroprotective strategies, use of anti- with an array of severe distur- ing but reversible, it is widely believed thrombotic agents (thrombolytic agents, bances in intracranial and sys- that patients with aSAH can benefit from heparin, and platelet inhibitors), prophy- Ttemic physiology that represent a unique laxis of seizures, and the approach to ce- management in an intensive care setting. challenge to the clinician. Surgical man- Recent years have seen a considerable rebral salt wasting and to cardiac dys- agement has traditionally emphasized the expansion in the use of image-guided en- function after aSAH. For each prevention of renewed intracranial bleed- dovascular therapies for aSAH, including controversy, a critical evaluation of the ing by clipping or wrapping the respon- coiling of aneurysms and balloon angio- available evidence is coupled with recom- sible aneurysm. Medical management is plasty or intraarterial drug delivery for mendations for further clinical investiga- based on the detection and treatment of cerebral vasospasm (1–4). These ad- tion. The review is selective, focusing on cerebral and extracerebral complications vances have occurred in a general setting the principal debates at the expense of of aneurysmal subarachnoid hemorrhage of increasing knowledge of aSAH epide- other equally important but arguably less (aSAH). Cerebral complications of aSAH miology, pathophysiology, diagnosis, and controversial issues (e.g., post-aSAH hy- include recurrent intracranial hemor- prevention and of significant refinements drocephalus and ventricular drainage). rhage, vasospasm, cerebral infarction, hy- in microsurgical technique and in medi- drocephalus, cerebral edema, and intra- cal therapy. There is a widespread percep- cranial hypertension; extracerebral Controversy 1: Surgical vs. tion that this broader understanding and Endovascular Aneurysm Repair complications include respiratory failure, expertise is yielding benefits in the form derangements of water and electrolyte of improved outcome after aSAH. Indeed, Endovascular coiling emerged as an homeostasis, myocardial dysfunction, a progressive increase in aSAH survival alternative to surgery in patients with over the past three decades has been re- intracranial aneurysms who were deemed ported in several studies (5–7). However, poor surgical candidates due to signifi- *See also p. 571. evidence of a direct relationship between cant neurologic injury, the presence of From the Division of Neurosciences Critical Care, aSAH outcomes and a specific strategy or severe medical co-morbidities, or difficult Departments of Neurology, Anesthesiology/Critical Care Medicine, and Neurological Surgery, Johns Hop- intervention is limited (2, 3, 8, 9). In surgical access to the aneurysm (1). More kins University School of Medicine, Baltimore, MD. several key areas of management, sup- recent work has sought to extend the Supported, in part, by U.S. Public Health Service porting data are lacking or equivocal in indications of endovascular coiling to National Institutes of Health NS NS046379 and by an nature, generating uncertainty and con- other patient categories. In a small ran- Established Investigator Grant (A. Bhardwaj) from the troversy among clinicians. American Heart Association. domized trial of 109 patients with aSAH, The authors have no financial interests to disclose. This review focuses on controversies 3- and 12-month clinical and neuropsy- Copyright © 2006 by the Society of Critical Care that are central to the acute management chological outcomes were the same be- Medicine and Lippincott Williams & Wilkins of aSAH. These include surgical vs. endo- tween the surgical group and the endo- DOI: 10.1097/01.CCM.0000198331.45998.85 vascular aneurysm repair, the diagnosis vascular group (10). This was followed by Crit Care Med 2006 Vol. 34, No. 2 511 the International Subarachnoid Aneu- after the first year for the endovascular spasm was either not significantly differ- rysm Trial (ISAT), a multiple-center, ran- group and 3,107 patient years of fol- ent (19–21) or slightly higher (22, 23) domized study of endovascular coiling vs. low-up for the neurosurgical group, with among surgically treated patients. An surgical clipping conducted in 2,143 pa- a mean follow-up of 4 yrs, risk of recur- early nonrandomized study of 156 pa- tients with aSAH who were deemed suit- rent aSAH was higher in patients ran- tients had suggested a higher rate of ce- able for either therapy. Posterior circula- domized to coiling (seven patients) com- rebral infarction in patients receiving en- tion aneurysms accounted for only 58 of pared with clipping (two patients), but dovascular vs. surgical therapy; however, 2,143 patients (as many of these patients mortality related to recurrent aSAH was the proportion of patients with poor ini- were not enrolled because coiling was equal in both groups. A higher risk for tial neurologic presentation was higher considered the preferred modality of seizures and poor cognitive outcomes in the endovascular group (24). treatment). At 1 yr, endovascular coiling was seen in the surgical group, and cu- Comment. The available data indicate was associated with dependency or death mulative 7-yr mortality curves showed that in patients with good neurologic in 23.5% of patients compared with more deaths in the surgical group com- grade aSAH who undergo treatment for 30.9% in the surgical group, a relative pared with coiling. The increased risk of aneurysms in the anterior circulation, risk reduction of 22.6% (p Ͻ .001). Of re-bleeding in the coiling group did not 1-yr outcomes are clearly superior after concern, however, nonprocedural re- seem to reverse the early benefit seen endovascular coiling when compared bleeding within 1 yr was higher in pa- with this modality. Notwithstanding its with surgical clipping. Follow-up of pa- tients randomized to endovascular treat- limitations, ISAT represents level I evi- tients receiving endovascular treatment ment (40 recurrent aSAHs, with 22 dence that in this patient population, en- in some studies suggests that despite deaths) compared with patients allocated dovascular coiling is associated with bet- good clinical results, a significant propor- to neurosurgical treatment (33 patients ter 1-yr outcomes, with trends toward tion of patients may require repeat endo- with aSAHs, 30-day mortality in 21 pa- superior long-term outcomes, when vascular or surgical therapy for residual tients) (2, 3). compared with surgical clipping. or recurrent aneurysmal lesions. How- Although widely regarded as a land- Apart from the recently published in- ever, long-term (Ͼ1 yr) clinical trends in mark trial, the ISAT has been criticized formation stemming from the ISAT trial, patients enrolled in ISAT do seem to sug- with regard to biases in patient selection, randomized trials comparing long-term gest that endovascular coiling is likely to low rates of randomization of eligible pa- outcomes after coiling vs. clipping of rup- retain its advantage over clipping as a tients, the definition of clinical equipoise, tured aneurysms are not available. How- superior procedure, and further fol- expertise of the neurosurgeons and inter- ever, in an analysis of patients who un- low-up of these patients is likely to add ventionists, the failure to use an opera- derwent coiling of unruptured aneurysms insight to this debate. Preliminary results tive microscope, the higher than ex- and were followed for a median of 22.3 from various studies have failed to con- pected morbidity in the surgically treated months, annual re-bleeding rates were sistently show an association between group, the absence of angiographic data 0.8% in the first year, 0.6% in the second treatment modality and the rate of de- after the initial treatment, the lack of year, and 2.4% in the third year after layed cerebral ischemia. For posterior long-term (Ͼ1 yr) follow-up, and the ap-