Radiology_Aug04 ORIGINAL ARTICLE 28 SA JOURNAL OF RADIOLOGY • August 2004 Abstract We performed an audit to determine the profile of cerebral aneurysms at the Universitas Hospital Bloem- fontein, the only government hospital with a vascular suite in the Free State and Northern Cape area. Two hun- dred and twenty-three government patients, diagnosed with cerebral aneurysms during the period 1 January 2000 to 31 December 2003, were included in the study. Of the 223 patients, 37.2% were male and 62.8% female. The patients’ average age was 45.5 years (range 11 - 78 years). Most patients (61.4%) were older than 40 years. The average age for males and females was 41.4 and 46.3 years, respectively, with the females being significantly older (95% CI: 1.7 - 8.2). Most patients had single aneurysms (65.5%). More females (42.9%) had multiple aneurysms compared with the males (20.5%) (95% CI females - males: 9.9 - 33.7%). Of the patients 40 years and younger, 22.1% had multi- ple aneurysms compared with 42.3% of the patients older than 40 years (95% CI: 7.8 - 31.7%). In our audit the females (when compared with the males) had a clear preponderance for cerebral aneurysms, were significantly older, and had a significant increase in multiplicity with an increase in age. Introduction The main cause of subarachnoid haemorrhage (SAH) is rupture of cerebral aneurysms.1 SAH is a very serious disease associated with high mortality and morbidity.1 It is still an open question whether population- wide screening for unruptured cere- bral aneurysms is indicated,2 while cerebral angiography remains the diagnostic gold standard.3,4 There have been numerous studies of the incidence of cerebral aneurysms. According to the WHO MONICA (Multinational Monitoring of Trends and Determinants in Cardiovascular Disease) Stroke Study no consistent pattern was observed in SAH attack rates in different popula- tions.5 We performed an audit to determine the profile of cerebral aneurysms at Universitas Hospital, Bloemfontein. Methods Universitas Hospital in Bloemfon- tein is the only tertiary hospital in the Free State and Northern Cape and also the only government hospital with a vascular suite in this area. All government patients with a suspected SAH are therefore sent to this unit for angiographic assessment. During the period 1 January 2000 to 31 December 2003, 223 patients were diagnosed with cerebral aneurysms. The angiogram reports of these patients were used for data collection. Reports of repeat and follow-up aneurysms were excluded. Angiography was perfomed using a Siemens angioscope unit. Four ves- sel studies were performed in most cases using the following projections: AP, left anterior oblique (LAO) 20º, right anterior oblique (RAO) 20º and lateral for the carotid arteries, and Townes and lateral projections for the vertebral arteries. Results Of the 223 patients, 83 (37.2%) were male and 140 (62.8%) were female. The patients’ average age was 45.5 years (range 11 - 78 years), with a peak (48.9%) between the ages of 36 and 50 years (Fig. 1). The majority of patients (61.4%) were older than 40 years. The average age for males was 41.4 years and 46.3 years for females, with the females being significantly older (95% CI: 1.7 - 8.2). The average age for males with single aneurysms was 40.5 years, and for multiple aneurysms, 41.1 years. The average age for females with single aneurysms was 43.1 years, and for multiple aneurysms, 50.5 years. Seventy-seven patients (34.5%) had multiple aneurysms while 146 patients (65.5%) had single aneurysms. In the female group, 60 (42.9%) had multiple aneurysms compared with 17 (20.5%) of the males (95% CI: females - males 9.9 - 33.7%). Of the patients 40 years and younger, 22.1% had multiple Cerebral aneurysms – an audit D J Louw MB ChB C de Vries MMedRad (D) Department of Diagnostic Radiology University of the Free State Bloemfontein G Joubert BA, MSc Department of Biostatistics University of the Free State Bloemfontein aneurysms compared with 42.3% of the patients older than 40 years (95% CI: 7.8 - 31.7%). The sites of the aneurysms are given in Fig. 2. In the patients with multiple aneurysms, each site was counted separately. The internal carotid artery and posterior commu- nicating artery accounted for the most sites, viz. 76 (22.8%) and 75 (22.5%), respectively. To determine seasonal variation, the year was divided into 3-month periods, starting with 1 September, indicating spring. The number of sin- gle aneurysms increased during win- ter (1 June - 31 August), but this was, however, not statistically significant (chi-square p-value 0.5370). Discussion Previous data suggest that cerebral aneurysms occur more frequently with increasing age,6 peaking in the fourth to fifth decade, and rarely occurring after 75 years.7,8 This is also reflected in our audit, with most patients (61.4%) older than 40 years. According to some authors cere- bral aneurysm is a disease with a female preponderance, with the mean age for women older than for men.3,9-11 In the WHO MONICA study no con- sistent pattern was observed in the sex ratio of attack rates in different popu- lations, with men having a higher incidence in Finland and Russia. Women had a higher incidence in Poland, Northern Sweden and Denmark. The incidence was the same for East Germany, China, Yugoslavia and Italy.5 In our audit the females had a clear preponderance accounting for 62.8% of the study population, and were significantly older (95% CI: 1.7 - 8.2). The female- to-male ratio also increased after the fourth decade, as found by Kongable and co-workers.10 The ratio increased to 1:2.1 in the fifth decade compared with 1:1.55 in the third decade. The overall ratio was 1:1.7. The incidence of multiple cerebral aneurysms has been variably assessed at between 5% and 33%.3,6,12-17 In this study, 34.5% of the patients had mul- tiple cerebral aneurysms (ratio 1:2). Of the patients older than 40 years, 42.3% had multiple aneurysms. Previous data also suggest that multi- plicity increases with age.6 Females had a significant increased incidence in our study (95% CI: 9.9 - 33.7%). There is a higher mortality associated in patients with multiple lesions.13,18 An apparent seasonal variation was found in this study, with an increase in single aneurysms during winter. This was, however, not statisti- cally significant and needs to be com- pared with other South African results. We also wanted to audit the size of the aneurysms, the shape of the neck and aneurysms, as well as treatment. Unfortunately these data were not available consistently enough on the reports to audit. This underlines the need to use a standardised format of reporting. References 1. Pakarinen S. Incidence, aetiology, and progno- sis of primary subarachnoid haemorrhage. A study based on 589 cases diagnosed in a defined urban population during a defined period. Acta Neurol Scand 1967; 43: Suppl 29, 1-28. 2. Wardlaw JM, White PM. The detection and management of unruptured intracranial aneurysms. Brain 2000; 123: 205-221. 3. van Gijn J, Rinkel GJ. Subarachnoid haemor- rhage: diagnosis, causes and management (Review) Brain 2001; 124: 249-278. 4. Mayberg MR, Batjer HH, Dacey R, et al. Guidelines for the management of aneurysmal subarachnoid hemorrhage. A statement for healthcare professionals from a special writing group of the Stroke Council, American Heart Association. Stroke 1994; 25: 2315-2328. 5. Ingall T, Asplund K, Mahonen M, Bonita R. A multinational comparison of subarachnoid hemorrhage epidemiology in the WHO MON- ICA stroke study. Stroke 2000; 31: 1054-1061. ORIGINAL ARTICLE 29 SA JOURNAL OF RADIOLOGY • August 2004 Fig. 1. Age distribution of the patients (N = 223). Fig. 2. Site of aneurysms (N = 3 34) (ICA = inter- nal carotid artery; Post com = posterior commu- nicating artery; MCA = middle cerebral artery; ACA = anterior cerebral artery; VB = verte- brobasilar system). 6. Wilson FM, Jaspan T, Holland IM. Multiple cerebral aneurysms — a reap- praisal. Neuroradiology 1989; 31: 232-236. 7. Clare CE, Barrow DL. 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Acta Neurol Scand 1966; 41: 356-362. 15. King G, Slade HW, Campoy F. Bilateral intracranial aneurysms. AMA Arch Neurol Psychiatry 1954; 71: 326-336. 16. Ostergaard JR, Hog E. Incidence of multiple intracranial aneurysms. Influence of arterial hypertension and gender. J Neurosurg 1985; 63: 49-55. 17. Sengupta RP, McAllister VL. Subarachnoid Haemorrhage. New York: Springer-Verlag, 1986. 18. Paterson A, Bond MR. Treatment of multiple intracranial arterial aneurysms. Lancet 1973; 1: 1302-1304. ORIGINAL ARTICLE 30 SA JOURNAL OF RADIOLOGY • August 2004