EDITORIAL Thromboembolism prevention after chronic subdural hematoma in the elderly A leap in the dark

Jose I. Suarez, MD The incidence of chronic subdural hematomas Reviews databases from Jan 2012 to May 2016. After Gregory Kapinos, MD, (cSDH) increases with age.1,2 Risk factors that con- performing a thorough review, the authors included 7 MS tribute to the occurrence of cSDH, apart from studies that met inclusion criteria, 4 of which pro- advancing age, include a history of falls, minor head vided combined data on anticoagulants and antipla- injury, use of anticoagulant or antiplatelet medica- telet use. They report that only one study found Correspondence to tions, bleeding disorders, heavy alcohol use, epilepsy, anticoagulant or antiplatelet agent use to be a factor Dr. Suarez: low intracranial pressure conditions, and hemodialy- for cSDH recurrence. Two studies reported similar [email protected] sis.1 The aged population also endures the highest risk increased odds of rebleeding when considering anti- Neurology® 2017;88:1880–1881 of atrial fibrillation and other conditions that predis- coagulant use alone (excluding antiplatelet agents pose them to devastating ischemic cardiac and cere- alone and combination treatment), with one study bral ischemic events.3 Antithrombotic therapy finding an increase in rebleeding risk. Conversely, constitutes evidence-based therapy to prevent these they found no association between antiplatelet agents ischemic events, but consensus holds that use of an- use and rebleeding. In addition, they found no ideal tithrombotic medications is also the most important timing to resume anticoagulants or antiplatelet risk factor that accounts for the increasing incidence medications. of cSDH in the elderly.1 This review has several strengths. First, the authors Patients who present with symptomatic cSDH, performed an extensive systematic review that whether on antithrombotics or not, are usually con- included all languages in numerous publishing plat- sidered for surgical treatment.2 About 10%–25% of forms. Second, the authors were compliant with cur- patients experience recurrent bleeding after the initial rent recommendations and registered this systematic surgical intervention, increasing morbidity and mor- review with the PROSPERO international prospec- tality.1,2 Many patients require resumption of antith- tive register of systematic reviews and reported it in rombotics in the postoperative period to prevent accordance with PRISMA criteria.5 Third, the au- embolic or ischemic events despite the risk of rebleed- thors assessed all the studies presented for bias and ing. Attempting to quantify this risk amidst a paucity quality, by using the GRADE quality assessment of high-quality data presents a major medical conun- tool.6 Fourth, the authors report acceptable agree- drum. Avoiding therapeutic inaction, clinicians use ment between the 2 independent reviewers who eval- available data, even if limited or difficult to interpret, uated the articles. and ultimately try to maneuver judiciously between This article also has weaknesses. All the studies re- Scylla and Charybdis. viewed were retrospective and, as such, subject to In this issue of Neurology®, Nathan et al.4 provide bias. In addition, the included studies either lacked a systematic review on the use of anticoagulation and or inconsistently reported data on timing of resump- antiplatelet agents among older adults (those over 65 tion of antithrombotics. Moreover, indications for years of age) with cSDH. Specifically, the authors anticoagulant or antiplatelet therapy were not avail- investigated the important clinical question of able. Furthermore, the included data are heteroge- whether or not to restart full anticoagulation or anti- neous with some studies including acute on chronic platelet agents (or both) in the early or late phase SDH, variable dosing of antithrombotics, and diverse following surgical treatment or intervention for indications for the antithrombotics.7,8 Finally, the cSDH in this population. To achieve this, they per- potential conflation of early reaccumulation (due to formed an update of a previous review (searched until early resumption of antiplatelet agents or gentle July 2012). The authors searched Medline, EM- anticoagulation for venous thromboembolic prophy- BASE, ISI Web of Knowledge, Google Scholar, laxis)7 with delayed reaccumulation or even subacute PLOS, and the Cochrane Register for Systematic recurrence of a SDH8 poses a substantial problem. See page 1889 From the Division of Vascular Neurology and Neurocritical Care (J.I.S.), Department of Neurology, Baylor College of Medicine, CHI Baylor St Luke’s Medical Center, Houston, TX; and Departments of Neurosurgery & Neurology (G.K.), Hofstra Northwell School of Medicine, Manhasset, NY. Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the editorial.

1880 © 2017 American Academy of Neurology ª 2017 American Academy of Neurology. Unauthorized reproduction of this article is prohibited. These shortcomings are not the fault of the investi- DISCLOSURE gators but reflect the quality of the studies available. The authors report no disclosures. Go to Neurology.org for full Well-conducted, prospective multicenter ran- disclosures. domized trials or national registries are needed to REFERENCES provide clear clinical guidance.7,9,10 Such studies 1. Kolias AG, Chari A, Santarius T, Hutchinson PJ. Chronic should capture indication for each antithrombotic subdural haematoma: modern management and emergent – agent, antithrombotic type and dosage, the timing therapies. Nat Rev Neurol 2014;10:570 578. 2. Huang KT, Bi WL, Abd-El-Barr M, et al. The neuro- of discontinuation prior to surgery and resumption critical and neurosurgical care of subdural hematomas. postoperatively, and whether clinical or radiologic Neurocrit Care 2016;24:294–307. deterioration prompted re-evacuation. Captured out- 3. Damani RH, Suarez JI. Secondary stroke prevention in comes need to include postoperative thromboem- nonvalvular atrial fibrillation. South Med J 2016;109: bolic events separated into venous vs arterial, as 721–729. well as distinguishing cerebral, coronary, and periph- 4. Nathan S, Goodarzi Z, Jette N, Gallagher C, Holroyd- eral arterial events. Only then would clinicians be Leduc J. Anticoagulant and antiplatelet use in seniors with chronic subdural hematoma: systematic review. Neurology able to balance thrombotic against hemorrhagic 2017;88:1889–1893. 9 risks, precisely using time to thrombosis against 5. MoherD,LiberatiA,TetzlaffJ,AltmanDG,GroupP.Pre- time to recurrent bleed, severity of the thrombosis, ferred reporting items for systematic reviews and meta-analyses: and rebleed,10 and ultimately use net clinical ratios the PRISMA statement. PLoS Med 2009;6:e1000097. with functional disabilities, quality of life data, and 6. Guyatt G, Oxman AD, Akl EA, et al. GRADE guidelines: cost-effectiveness analysis. 1: introduction: GRADE evidence profiles and summary of findings tables. J Clin Epidemiol 2011;64:383–394. Based on our assessment of the data presented, 7. Guha D, Coyne S, MacDonald RL. Timing of the we agree with the authors of this systematic review resumption of antithrombotic agents following surgical that there are still many uncertainties regarding evacuation of chronic subdural hematomas: a retrospective resuming antithrombotic agents in older adults cohort study. J Neurosurg 2016;124:750–759. with cSDH.4 Until further data become available, 8. Okano A, Oya S, Fujisawa N, et al. Analysis of risk factors it is reasonable to recommend that anticoagulants for chronic subdural haematoma recurrence after burr hole surgery: optimal management of patients on antiplatelet not be given indiscriminately postoperatively to all therapy. Br J Neurosurg 2014;28:204–208. cSDH patients at risk of thromboembolic events. 9. Spyropoulos AC, Albaladejo P, Godier A, et al. Periproce- Clinicians should carefully discuss the risk of sub- dural antiplatelet therapy: recommendations for standard- dural reaccumulation and recurrence associated ized reporting in patients on antiplatelet therapy: with anticoagulants with individual patients and communication from the SSC of the ISTH. J Thromb – their families. Practitioners may also select antipla- Haemost 2013;11:1593 1596. 10. Periprocedural Management of Anticoagulation Writing telet agents as a somewhat safer, albeit potentially Committee, Doherty JU, Gluckman TJ, Hucker WJ, less effective, alternative, especially for elderly pa- et al. 2017 ACC Expert consensus decision pathway for tients at high risk of myocardial infarction or periprocedural management of anticoagulation in patients stroke.9,10 with nonvalvular atrial fibrillation: a report of the American College of Cardiology Clinical Expert Consen- STUDY FUNDING sus Document Task Force. J Am Coll Cardiol 2017: No targeted funding reported. S0735–S1097.

Neurology 88 May 16, 2017 1881 ª 2017 American Academy of Neurology. Unauthorized reproduction of this article is prohibited.