LAUSR

Dear Editor, We read with great interest the recently published article by Sorteberg et al. [4] on the timelines of aneurysmal subarachnoid haemorrhage (aSAH) rebleeds. We would like to complement the authors for their attempt at qualitative and quantitative investigation of basic logistic and clinical parameters associated with rebleeding in aSAH. These may have significant influence on outcomes but are usually not given adequate consideration while preparing treatment protocols. They retrospectively analysed 4 years of registry data, including 544 patients with aSAH and elucidated various temporal parameters of rebleeds, association of rebleeds with different factors, and mode of treatments. Although aneurysmal SAH is less frequently angionegative [2], it is a radiologically defined entity usually exhibiting better prognosis [1]. We feel it should have either been definitively excluded or, if not excluded, a subgroup analysis would have been prudent. Authors stated that two patients rebled with no source being identified but their specific timeline of rebleeding and outcomes were not elaborated upon. Angionegative SAH patients were specially mentioned as a separate group by Naidech et al. in their study investigating the factors affecting rebleeds and its impact in all cause nontraumatic SAH [3]. The case of multiple aneurysms was similarly not touched upon. If these patients were not definitely excluded, the method of distinguishing fresh bleeds from another aneurysm and rebleeds from an aneurysm that bled previously would need mention. Although the incidence, temporality, and degree of vasospasm have been methodologically defined and set as a parameter for investigation, data regarding its relation with rebleed has not been reported. Its association with treatment modalities, on the other hand, has been demonstrated clearly. In a similar vein, we suggest that myriad clinical factors like inhospital mortality, 1-year mortality, and good functional outcomes (mRS 0–2) mentioned in the table comparing them between treatment modalities should instead be presented in relation to rebleed-based groups. This would not only have been interesting to note but would also be in line with the primary objective. Authors have reported increased rebleed rate in patients arriving at nighttime. However, in Fig. 2, the highest rebleed is seen in the patients arriving between 0600 and 0859 h, while for all other time periods, it was more or less similar. There seems to be a contradiction in the text and figure, and we feel it needs more elaboration and clarification. EVT has been reported to have increased lag time between arrival and treatment, and reasons explaining this have been suggested. But elsewhere, it has also been reported to commence earlier than surgeries during night hours. We feel if factors eliciting such shifts could be elucidated in more detail, they would be illustrative regarding logistic nuances to other neurosurgical centers. Increased delays in surgical intervention during the night could be contributory and is worth exploring further. To summarize, we once again congratulate the authors for this thought-provoking study that has attempted to classify and quantify the effect of practical parameters felt to be impactful by surgeons in context of aSAH rebleeds. Outcomes are significantly worsened in the presence of rebleed episodes [5]. Any attempt to modify factors that influence rebleeding must first be supported by information about those factors, providing that is felt to be the primary objective of this study.