The impact of the international subarachnoid aneurysm trial (ISAT) on the management of aneurysmal subarachnoid haemorrhage in a neurosurgical unit in the UK

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Abstract

Objective

To review the changes in the management of aneurysmal subarachnoid haemorrhage (SAH) in a single neurosurgical unit in the UK, following the publication of the international subarachnoid aneurysm trial (ISAT).

Methods

The presentation, investigations, treatments and outcome data of all patients admitted with SAH to the neurosurgical unit between February 2001 and May 2003 were prospectively recorded in a database. The total period studied was split in to three blocks, around the time of publication of the ISAT in October 2002 (period 1 = February–December, 2001; period 2 = January–September, 2002 and period 3 = October 2002 to May 2003).

Results

Of the 177 patients admitted with presumed SAH, 130 patients with evidence of an aneurysm on angiograms were included in the study. The mean age was 53 ± 1 years, 92 (71%) patients were WFNS grade 1 or 2 and 77 (60%) were Fischer grade 2 or 3. These parameters were unchanged over the study period. Overall, 60 patients (46%) underwent a craniotomy for clipping or wrapping of aneurysm, 60 (46%) underwent endovascular embolisation of the aneurysm and 10 patients (8%) were managed conservatively. Over the study periods 1–3, the proportion of patients undergoing open surgery decreased (from 51 to 31%) while endovascular treatment of aneurysms increased (35–68%; p < 0.01). Over the same time points there was a non-significant trend towards better Glasgow outcome scores at 6 months follow-up. The management mortality for all WFNS grades of patients with SAH was eight deaths (14%). The mortality in the surgical group was 3 patients (5%) and there were no deaths in the endovascular group. Over the study periods 1–3, there was a decrease in the mean total duration of hospital stay (from 23.6 to 15.5 days; p < 0.05) in WFNS grade 1 and 2 patients and this was related to a shorter duration of hospital stay in the endovascular than surgical group of patients (p < 0.05). The mean delay in obtaining an angiogram increased over the study periods 1–3 (1.1–2.3 days; p < 0.05).

Conclusions

This observational study highlights the changing pattern of management of SAH and the potential difficulties that could be encountered. The proportion of patients undergoing endovascular treatment of aneurysms has increased following the publication of the ISAT study. The associated increase in the delay in obtaining an angiogram may reflect the increased workload encountered by the neuroradiologists.

Introduction

Subarachnoid haemorrhage (SAH) secondary to rupture of an intracranial aneurysm remains a relatively common neurosurgical condition with an incidence of 6–8 cases per 100,000 population [1], [2], [3]. There are various treatment options available for ruptured aneurysms including surgical and endovascular means. Class I evidence for the relative merits of one treatment option over the other is scanty.

In the 1960s, a series of trials demonstrated the benefit of surgical treatment over conservative management for common anterior circulation aneurysms [4], [5], [6]. Although endovascular embolisation of aneurysms has been in clinical use since the 1990s, its use varies widely. This new mode of treatment for intracranial aneurysms has been compared to open surgery in randomised trials [7], [8], [9], [10]. The most recent of these studies, international subarachnoid aneurysm trial (ISAT) was a multicentre randomised trial, which compared neurosurgical clipping with coiling for ruptured anterior circulation aneurysms that were considered suitable for either treatments [8]. The full study commenced in 1997, but after a planned interim analysis in May 2002, further recruitment of patients was suspended by the data monitoring committee [8]. Analysis of the outcome at 1-year follow-up revealed a 6.9% absolute risk reduction in dependency or death for the endovascular group (23.7%) in comparison with patients allocated to surgery (30.6%) [8]. Both the British and American Societies for Neurosurgery have issued position statements on ISAT, and the long-term follow-up data from the ISAT cohort of patients is awaited [1], [2] We report the impact of the ISAT study on the management of aneurysmal SAH in a medium sized neurosurgical unit in the UK.

Section snippets

Methods

The details of all patients with SAH admitted to the neurosurgical unit at Charing Cross hospital were prospectively recorded in a database from 2001 (Microsoft Access). This observational study reports on patients admitted between February 2001 and May 2003. The 27-month study period was split into three parts: study period 1—February to December, 2001; study period 2—January to September, 2002; study period 3—October 2002 to May 2003. The time periods were selected to evaluate the impact of

Overall results

Over the study period, a total of 177 patients were admitted with possible SAH. Of these 130 patients were noted to have cerebral aneurysms on four vessels and/or CT angiography. The mean age of these patients was 53 ± 1 years (range 25–80) and 81 patients (62%) were females. The WFNS grades of patients at presentation were as follows: grade 1, 64 (49%); grade 2, 28 (22%); grade 3, 18 (14%); grade 4, 12 (9%); grade 5, 8 (6%). The Fisher grades of the initial CT scans of brain were as follows:

Discussion

The frequency of the use of surgical clipping and endovascular embolisation of ruptured intracranial aneurysms varies widely among the neurosurgical units around the world. This in part reflects the relative lack of class I evidence on the best form of treatment modality. The recent publication of the 1-year outcome data from the ISAT study has revealed better outcome for those patients with ruptured anterior circulation aneurysms treated by endovascular means [8]. Although aspects of the ISAT

Conclusion

Following the publication of ISAT study, the modality of treatment of aneurysmal SAH has changed in favour endovascular therapy in our unit. This was associated with reduced length of hospital stay, increased delays in obtaining an angiogram and re-bleeds from unsecured aneurysms. Adequate expansion of the endovascular services is necessary prior to an increase in the endovascular treatment of cerebral aneurysms.

Conflicts of interest

None.

Acknowledgements

We are grateful to Drs I. Colquhoun, A. Waldman and M. Patel for providing the Neuroradiology service at our institution.

References (18)

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