Short-term aspirin use ups risk of aneurysmal subarachnoid haemorrhage
Patients taking aspirin for <3 months may have an increased risk of aneurysmal subarachnoid haemorrhage (aSAH), according to a meta-analysis, although the studies included showed a substantial level of heterogeneity.
Researchers searched electronic databases for studies assessing the risk of aSAH among aspirin vs nonaspirin users. Data were analysed using inverse variance and random-effects models.
Pooled data from seven studies showed no significant difference between aspirin use of any duration or frequency and nonuse (odds ratio [OR], 1.00; 95 percent CI, 0.81 to 1.24; p=0.99). Short-term use of aspirin (<3 months) was found to be significantly associated with the risk of aSAH (OR, 1.61; 1.20 to 2.18; p=0.002).
However, the risk of aSAH with intermediate and long-term use (3 to 12 months, 1 to 3 years and >3 years) did not differ when compared with nonuse. Infrequent aspirin use (≤2 times per week) or frequent use (≥3 times per week) showed no association with aSAH.
The present data suggest that short-term aspirin users are at a greater risk of aSAH, but the risk among intermediate and long-term users does not differ compared with that among nonusers. A well-designed randomized controlled trial is needed to determine whether long-term aspirin use can provide any benefit in terms of risk of aSAH, researchers said.
To date, aSAH remains a morbid and serious condition with relatively unchanged incidence in many countries including the US. This is despite of an increase in the number of unruptured intracranial aneurysms treated with endovascular techniques or microsurgical clipping. The high mortality rate associated with aSAH is often attributed to the initial haemorrhage event or rehaemorrhage prior to aneurysm obliteration. [Neurosurgery 2013;73:217–222; Lancet Neurol 2009;8:635–642; Stroke 2015;46:2452–2457]
Available means of aSAH detection rely on noninvasive imaging, either with ultrasound or computed tomography angiography. Perfusion-based imaging modalities can be used to detect clinically significant alterations in cerebral blood flow. Catheter based digital subtraction angiography is used to diagnose vasospasm and is considered the gold standard, with vasospasm surveillance aiding in the identification of changes in vessel calibre and/or blood flow prior to neurological deterioration. [J Clin Neurosci 2014;21:2135–2139]