Viscoelasticity and Orthostatic Intracranial Pressure

J Neurosurg 133:1616–1633, 2020 Neurosurgical Forum LETTERS TO THE EDITOR Aneurysm rebleeding after In addition, as for the diagnosis of postoperative rebleeding, the authors define it as new SAH on postopera- subarachnoid hemorrhage tive CT scans during the period from the operation to 28 days thereafter. To our knowledge, postoperative rebleed- TO THE EDITOR: We read with great interest the ing always occurs from the operation to 7 days thereafter, retrospective cohort study by Horie et al.1 (Horie N, Sato so we suggest correcting the timescale for postoperative S, Kaminogo M, et al. Impact of perioperative aneurysm rebleeding. rebleeding after subarachnoid hemorrhage [published on- Finally, the authors concluded that multiple aneurysms line September 13, 2019]. J Neurosurg. doi: 10.3171/ 2019. are protective factors for preoperative rebleeding. Howev- 6.JNS19704). The authors found that aneurysm rebleeding er, in a recent article by Suzuki et al.,2 multiple aneurysms after subarachnoid hemorrhage (SAH) has specific char- are considered as a risk factor for unruptured aneurysms, acteristics in the preoperative, intraoperative, and postop- so there is somewhat of a controversy. erative periods, involving aneurysm size, heart disease, aneurysm location, family history, clipping, coiling, etc. Lesheng Wang, MM According to Horie and colleagues, their study is the first Jincao Chen, MD, PhD to assess the characteristics and predictors of aneurysmal Zhongnan Hospital of Wuhan University, Wuhan, China SAH rebleeding in the preoperative, intraoperative, and postoperative periods. We would like to express our re- References spect for their achievements and to share some comments 1. Horie N, Sato S, Kaminogo M, et al. Impact of periopera- with the authors. tive aneurysm rebleeding after subarachnoid hemorrhage Firstly, and most importantly, the data were collected [published online September 13, 2019]. J Neurosurg. from 1 university hospital and 10 affiliated hospitals. The doi:10.3171/2019.6.JNS19704 authors did not consider the role of these medical institu- 2. Suzuki T, Takao H, Rapaka S, et al. Rupture risk of small un- tions in their analysis. Depending on the different medical ruptured intracranial aneurysms in Japanese adults. Stroke. levels of doctors in these hospitals, different degrees of 2020;51(2):641–643. surgical instruments and equipment, and different management methods after operation, these factors could af- Disclosures fect the probability of aneurysm rupture during and after The authors report no conflict of interest. surgery. Therefore, it is difficult to control bias in data collected from 11 hospitals. Correspondence Secondly, their article does not provide inclusion cri- Jincao Chen: [email protected]. teria for the study subjects but simply describes exclusion INCLUDE WHEN CITING criteria. It only rules out subjects younger than 18 years Published online April 3, 2020; DOI: 10.3171/2019.12.JNS193444. of age and nonaneurysmal SAH including dissection. However, patients with intracranial hemorrhage and on the verge of death, patients with vital organ diseases, and Response older patients (> 75 years of age) should also be excluded We thank Drs. Wang and Chen for their comments. It is because the rate of postoperative mortality and disability difficult to completely exclude technical or surgical equip- is probably high in these patients, and it is difficult for sur- ment bias in all clinical studies, including ours. In this gical intervention to improve the survival rate. study, the surgical or endovascular procedure was per- Thirdly, the evaluation of aneurysm rebleeding af- formed by an experienced, certified physician. Regarding ter operation was defined as new SAH on postoperative inclusion criteria, we believe it is very important to pro- CT scans. We think there are some flaws in this defini- vide real-world data to assess rebleeding and clinical out- tion because postoperative hemorrhage on CT can have come in the aging population. In this study, most postoper- false-negative results and will affect the clinical outcome ative rebleeding occurred a couple of days after treatment. of different aneurysm surgeries (clipping vs endovascular In terms of the association between multiple aneurysms coiling) in terms of postoperative rebleeding. and rebleeding, it is difficult to explain why the presence 1616 J Neurosurg Volume 133 • November 2020 Unauthenticated | Downloaded 09/30/21 04:57 PM UTC Neurosurgical forum of multiple aneurysms negatively affected preoperative re- smoking on aneurysm growth. Second, there is limited bleeding, a finding contrary to our expectations. Suzuki et analysis of the role of hypertension in the growth of the al. reported that the presence of multiple aneurysms was a aneurysm. Also, based on recall bias, it is not clear why risk factor for the rupture of small intracranial aneurysms, only the smoking risk factor was excluded and no other and it is not possible to simply discuss the factor of mul- parameters were treated and interpreted similarly. It is tiple aneurysms because aneurysm size and aneurysm sta- necessary to distinguish recall bias from simply inaccu- tus (initial rupture or rebleeding) are different. rate information; several studies suggest that there is a greater likelihood of recall bias when recall is poor, which Nobutaka Horie, MD, PhD constitutes the majority of cases.8 It is important to con- Shuntaro Sato, PhD sider that if a patient had a recall bias for smoking, then Makio Kaminogo, MD, PhD this same patient would have a recall bias for other events Yoichi Morofuji, MD, PhD as well (of course this assumption may not be true, but it is Tsuyoshi Izumo, MD, PhD possible). Another very important point is the conclusion Takeo Anda, MD, PhD of Zanaty et al.’s article, namely: “However, smoking is not part of the PHASES [population, hypertension, age, Takayuki Matsuo, MD, PhD size of aneurysm, earlier SAH from another aneurysm, On behalf of the Nagasaki SAH Registry Study and site of aneurysm] clinical score.” This finding from Nagasaki University School of Medicine, Nagasaki, Japan the PHASES clinical score needs to be interpreted with caution. Bijlenga et al.9 and Greving et al.10 showed that INCLUDE WHEN CITING cumulative risk factors did not add value to prediction Published online April 3, 2020; DOI: 10.3171/2020.2.JNS193536. of aneurysm rupture. However, the authors also did not ©AANS 2020, except where prohibited by US copyright law rule out the role of individual factors as an independent predictor of outcome. The authors further suggested that a change in smoking behavior (e.g., cessation) was probably one reason for the absence of risk effect on aneurysm Is aspirin a new silver bullet for rupture. The authors further suggested that the effect of continued smoking should not be interpreted as neutral for reducing the growth of intracranial assessing the risk factors for intracranial aneurysm rup- aneurysms? ture.4 Zanaty et al. should be commended and thanked for this innovative treatment. However, detailed analysis of smoking behavior should be performed objectively while TO THE EDITOR: We read with great interest the re- assessing various risk factors for growth of cerebral aneu- search by Zanaty et al.1 (Zanaty M, Roa JA, Nakagawa rysms. In that respect, definitely, a very well-recognized D, et al. Aspirin associated with decreased rate of intra- risk factor in such diseases must not be skipped. cranial aneurysm growth [published online October 29, 2019]. J Neurosurg. doi:10.3171/2019.6.JNS191273) and Rafael Martinez-Perez, MD, PhD we congratulate the authors for figuring out a solution for Institute of Neurosciences, Universidad Austral de Chile, Valdivia, Chile the management of relatively smaller unruptured intrace- Wexner Medical Center, The Ohio State University, Columbus, OH rebral aneurysms, as literature had hypothesized earlier.2 The article is well written, and the authors have demon- Guru Dutta-Satyarthee, MCh strated that aspirin administration is associated with de- Neurosciences Centre, AIIMS, New Delhi, India creased growth of unruptured intracranial aneurysms. Ezequiel García-Ballestas, MD We note that aspirin is a well-known drug that is widely Center of Biomedical Research (CIB), University of Cartagena, used in clinical praxis for an extensive variety of indica- Cartagena de Indias, Colombia tions including the prevention of cardiovascular events.3 Hudson et al. showed evidence of aspirin reducing the rate Amit Agrawal, MD of growth of aneurysms. COX-2 (cyclooxygenase-2) and All India Institute of Medical Sciences, Madhya Pradesh, India mPGES-1 (microsomal prostaglandin E2 synthase–1) are Luis Rafael Moscote-Salazar, MD both inhibited by aspirin. These substances have a cru- Center of Biomedical Research (CIB), University of Cartagena, cial role in aneurysm pathogenesis.4 However, there is a Cartagena de Indias, Colombia more complex interaction among aspirin, smoking, hypertension, and cerebrovascular diseases, including the References increased risk of cerebral aneurysm growth. Smoking is 1. Zanaty M, Roa JA, Nakagawa D, et al. Aspirin associ- known to exacerbate hypertension, stroke, pulmonary dis- ated with decreased rate of intracranial aneurysm growth ease, heart diseases, and atherosclerosis.5 Smoking also [published online October 29, 2019]. J Neurosurg. exacerbates hypertension—with increased risk of malig- doi:10.3171/2019.6.JNS191273 nant, renovascular hypertension6—as well as being a risk 2. Starke RM, Chalouhi N, Ding D, Hasan DM. Potential role 7 of aspirin in the prevention of aneurysmal subarachnoid factor for intracranial aneurysm rupture. hemorrhage. Cerebrovasc Dis. 2015;39(5–6):332–342. We want to highlight some important issues that this 3. Russo NW, Petrucci G, Rocca B. Aspirin, stroke and drug- study raises. First, there is the inability to measure the drug interactions. Vascul Pharmacol. 2016;87:14–22. smoking status of the studied cohort and the impact of 4. Hudson JS, Marincovich AJ, Roa JA, et al. Aspirin and intracranial aneurysms. Stroke. 2019;50(9):2591–2596. J Neurosurg Volume 133 • November 2020 1617 Unauthenticated | Downloaded 09/30/21 04:57 PM UTC Neurosurgical forum 5.

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