Elsevier

Surgical Neurology

Volume 63, Issue 3, March 2005, Pages 229-234
Surgical Neurology

Vascular
Subarachnoid hemorrhage on computed tomography scanning and the development of cerebral vasospasm: the Fisher grade revisited

https://doi.org/10.1016/j.surneu.2004.06.017Get rights and content

Abstract

Background

The Fisher grade (FG) is widely used to predict cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH). We revisited the grading scale to determine its validity in the era of modern management.

Methods

We retrospectively reviewed the records of 134 patients with SAH. The amount and distribution of subarachnoid blood on admission computed tomography (CT) scan was quantified according to the FG and compared with development of symptomatic vasospasm.

Results

We reviewed 134 patients (median age, 54) who presented with aneurysmal SAH. Six (5%) were FG 1, 34 (25%) were FG 2, 25 (19%) were FG 3, and 69 (51%) were FG 4. Symptomatic vasospasm developed in no (0%) FG 1, 8 (24%) FG 2, 7 (28 %) FG 3, and 13 (19%) FG 4 patients (28 of 134 total patients; 21%). Development of symptomatic vasospasm was not associated with admission FG, Hunt and Hess grade, age, sex, or location of blood on presenting CT scan. Elevated transcranial Doppler blood flow velocity was associated with blood in the basal cisterns (P = .0047), lateral ventricles (P = .026), or blood in any ventricle (P = .04). Postoperative angiograms were obtained in 57 patients; moderate to severe vasospasm was observed in 5 (15%) FG 2, 6 (24%) FG 3, and 14 (20%) FG 4 patients. Twenty patients (71%) with symptomatic vasospasm had moderate or severe angiographic vasospasm. Angiographic vasospasm was associated with intraventricular blood (P = .054) but not with FG.

Conclusions

Symptomatic vasospasm occurred in 21% of cases. The FG correlated with symptomatic vasospasm in only half the patients. A new predictive CT grading scale for vasospasm may be necessary.

Introduction

Delayed cerebral ischemia from cerebral artery vasospasm after aneurysmal subarachnoid hemorrhage (SAH) is a known cause of morbidity and mortality. It is important to predict which patients are at risk for vasospasm, because its management relies significantly on prevention. The Fisher computed tomographic grading scale described by Fisher et al [4] in 1980 is widely used to predict which patients are at risk to develop delayed cerebral ischemia (Table 1). The grading scale described the amount and distribution of subarachnoid blood seen on initial head computed tomography (CT) as it correlated to the development of cerebral vasospasm. Fisher et al found that symptomatic vasospasm only tended to occur in the major subarachnoid blood vessels that were initially surrounded by a thick subarachnoid clot. Though the original manuscript described the findings as preliminary, the scale derived from the 4 groupings of Fisher et al has become a standard tool for initial patient evaluation and prediction of likelihood of delayed cerebral ischemia after SAH.

Evaluation and treatment of patients with ruptured aneurysms have evolved the description of the Fisher grade (FG) in 1980. Modern CT scanners have significantly improved resolution for small volumes of intracranial blood compared to those available in 1980. In addition, less than half the patients included in the Fisher et al [4] study had their CT scan on the day of aneurysm rupture. Today, most patients are evaluated and imaged on the day of hemorrhage. Significant changes in treatment include early aneurysm occlusion, the use of calcium channel blockers, which may improve clinical outcome in aneurysmal SAH, and using hypervolemic, hypertensive, hemodilution (triple “H”) therapy at the onset of documented vasospasm in an attempt to maximize perfusion to areas of brain fed by spastic vessels. These management strategies were not used in 1980. Also, supplemental studies such as transcranial Doppler sonography (TCD) developed during the past decade now play an important role in assessing patients for vasospasm. In view of this it is important to determine whether the FG is a useful tool to predict vasospasm in the modern era. In this study, we retrospectively reviewed the medical records, CT scans, angiograms, and TCD findings of 134 consecutive patients with aneurysmal SAH to determine whether the FG reliably predicts vasospasm. Our results suggest that the FG may need to be revised.

Section snippets

Patient population

We retrospectively reviewed the medical records including hospital charts, CT scans, angiograms, and TCD findings of 134 consecutive patients with a diagnosis of SAH treated at the Hospital of the University of Pennsylvania. Patients with SAH due to trauma, arteriovenous malformations, or of unknown etiology were excluded from the study. Subarachnoid hemorrhage was diagnosed by either CT scanning or lumbar puncture. Patient demographics, date of SAH, day of CT scan, FG, and Hunt and Hess grade

Patients

There were 134 patients, including 40 males and 94 females (median age, 54 years; range, 16-82 years) (Table 2). The FGs and Hunt and Hess grades are listed in Table 2. All patients underwent preoperative digital subtraction angiography except one patient who presented with a large temporal hematoma that required emergent evacuation. In this patient, the presence of an aneurysm was confirmed intraoperatively. There were 116 anterior circulation and 18 posterior circulation ruptured aneurysms.

Discussion

In this retrospective study, we evaluated the CT, angiographic, and TCD findings of 134 patients with aneurysmal SAH to determine whether the initial CT severity of SAH determined by the FG predicts symptomatic cerebral vasospasm. The study was undertaken because there have been significant advances in neurologic imaging and in SAH management since the FG was devised more than 20 years ago that may now bias or invalidate the accuracy of the original grading system. Our results suggest that the

Conclusions

The FG did not reliably predict symptomatic vasospasm in this series of patients. The only admission CT finding that seemed to predict symptomatic vasospasm was intraventricular blood. There was no correlation between volume of a subarachnoid blood clot and development of symptomatic vasospasm. Our results do support the correlation of TCD findings to the development of both symptomatic and angiographic vasospasm. For those patients who did develop symptomatic vasospasm, there were more

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