"The relation between size of cerebral aneurysm and outcome in patients with Subarachnoid hemorrhages"

Between 5%-10% of strokes are due to subarachnoid hemorrhages (SAH). Although hemorrhage is usually from rupture of aneurysms or arteriovenous malformation but about 20% of cases will not have any specific causes.

Following subarachnoid hemorrhage with it's characteristic clinical picture of sudden onset headaches with a severity never experienced previously by the patients, 50% of the patients die where as around 10%-20% patients remain dependent on various help. Neurologists and Neurosurgeons therefore often advise preventive treatment for unruptured aneurysms, depending on the age of the patients, the surgical risk as well as the size of the unruptured aneurysm. Large aneurysms have a higher risk for complication but also poses higher risk for complications of treatment The decision on preventive operation might change if outcome is also influenced by the size of the aneurysm.

Until recently the size of aneurysm could be determined only by means of conventional angiography but this technique has limitations in studying the relation between the size and outcome. CT angiography (CTA) provides with a more accurate data on aneurysm size as well as enable to study the relation between the size and outcome.

Some 100plus patients with SAH admitted to the Utrecht University Hospital, The Netherlands between mid 1995 and early 1997 were studied, where in diagnosis of SAH was based on CT findings or by Xanthochromia in case of negative CT. Aneurysm with an diameter of at least 10mm was considered to be large. The sizes of the ruptured aneurysm based on CTA as a matter of fact ranged from 1. 5 to 24 mm. Patients with large aneurysms tended to be operated on less frequently, to have more repeat hemorrhages and fewer episodes of ischemia and to die more often from the impact of primary bleeding. It was found that 63% of patients with large aneurysms had a much poor outcome, compared to 41 % of patients with small aneurysms.

It was evident from the study that patients with large aneurysms have a greater chance of poor outcome following SAH, than patients with smaller aneurysms. On the other hand patients with large aneurysms more often have poor clinical condition on admission but the risk of clinical and surgical complications is essentially the same as patients with small aneurysms. A limitation of this study was possibly a selection bias in selecting cases but even if that could be overcome the overall result would still reflect the same.

Moreover, in the study it was implied quite clearly that the poor outcome on the larger proportion of the cases with large aneurysms who have not been operated could be better explained by the worse clinical condition from the outset rather than a more chance of re hemorrhage and thus a consequence rather than a causal factor of the poor outcome.

For further information: Eveline Jroos, M.D.; Gabriel J.E. Rinkel, M.D.; Birgitta K. Velthuis, M.D.and Ale Algra, M.D.: Neurology 2000;54:2334-2336.

Abstract by Syed S. Rahman, M.D.
House Staff Physician
Coma Recovery Unit/ TBI
Jamaica Hospital