Review article
Ukrainian Neurosurgical Journal. 2025;31(1):12-15
https://doi.org/10.25305/unj.318910
Department of neurosurgery, Institute of Medical Sciences and Sum Hospital, Bhubaneswar, Odisha, India
Received: 24 December 2024
Accepted: 24 January 2025
Address for correspondence:
Suryapratap Singh Tomar, OPD Number 75, Upper Ground (UG), IMS & SUM Hospital, Bhubaneswar, Odisha, 751015, India, e-mail: drspst10@gmail.com
Aspirin is frequently used to prevent ischemic episodes, either directly or indirectly. Long-term aspirin therapy can increase intraoperative blood loss and have an impact on blood clot development during surgery. This is particularly crucial for neurosurgery and other high-risk surgeries. There is currently no clinical evidence to support the European Society of Cardiology (ESC) recommendation that aspirin should be discontinued at least one week before neurosurgical intervention. In addition to summarizing current clinical data on bleeding risk associated with chronic aspirin therapy in neurosurgical patients, including brain tumour surgery, cerebrovascular procedures, and spinal surgery, this narrative review presents evidence that casts doubt on the need for aspirin interruption in neurosurgical patients. It also discusses options for monitoring the effect of aspirin and the clinical implications of these methods.
Key words: brain tumour; cerebrovascular surgery; spinal surgery; aspirin; neurosurgery; postoperative complications; bleeding risk
Introduction
Due to its well-known ability to reduce platelet aggregation, aspirin (acetylsalicylic acid, ASA) is frequently used for either primary or secondary prevention of ischemic events [1]. Long-term aspirin therapy can also increase intraoperative blood loss and impact blood clot formation during surgery [2]. Because even mild haemostatic problems can result in serious postoperative consequences, such as acute cerebral bleeding, this is particularly significant for high-risk surgeries, including neurosurgery [3]. Historically, expert consensus—rather than clinical evidence—has determined recommendations for discontinuation of aspirin therapy before neurosurgical procedures [4]. The 2022 ESC guidelines continue to recommend stopping aspirin therapy at least 7 days before surgeries in patients with a high peri-operative bleeding risk (e.g., undergoing complex brain surgeries, spinal surgery or certain neurosurgical operations), have repeatedly reiterated this recommendation over the years [5]. Clinical evidence gathered from observational studies in patients who have had spinal and brain surgery, however, does not support the idea that preoperative long-term aspirin therapy increases the risk of postoperative haemorrhage. Instead, there is growing evidence of its benefits in mitigating postoperative thromboembolic events [6, 7].
Current clinical data on bleeding risk associated with chronic aspirin therapy in neurosurgical patients, including brain tumour surgery, cerebrovascular procedures, and spinal surgery, are summarized in this narrative review along with evidence that casts doubt on the need for aspirin interruption in neurosurgical patients. It also discusses options for monitoring the effects of aspirin and the clinical implications of these methods.
Antiplatelet effect of aspirin
Aspirin's antiplatelet effect is achieved by suppressing the synthesis of thromboxane A2 (TXA2) after blocking the activity of cyclooxygenase (COX) within platelets [8]. Aspirin efficiently inhibits this method of platelet activation, and thromboxane A2 is a key player in the amplification of platelet aggregation [9]. Aspirin's antiplatelet effect has several clinically significant features, including its enhanced efficacy at low doses (75–325 mg/d). This effect is due to the lack of concurrent inhibition of prostacyclin in endothelial cells and irreversible COX inhibition, which distinguishes aspirin from other nonsteroidal anti-inflammatory drugs (NSAIDs). The duration of the antiplatelet effect of medications like ibuprofen, ketorolac, etc. correlates with the elimination time because they reversibly compete with the arachidonic acid substrate at the COX active site. Because aspirin irreversibly acetylates platelet COX, its antiplatelet action lasts for several days following a single dose [10]. After a single aspirin intake, the ability to produce TXA2 can only be restored with the generation of new platelets, which are regenerated by around 10% per day. Adenosine diphosphate, collagen, and thrombin are examples of non-TXA2-dependent activators of platelet aggregation that can circumvent the aspirin-dependent mechanism and produce effective coagulation. It makes aspirin a relatively weak antiplatelet agent because it only partially inhibits platelets [8]. Furthermore, up to 25% of patients may not respond to standard aspirin treatment [11].
Aspirin antiplatelet effect assessment
Increased bleeding time is the direct clinical effect of aspirin absorption on primary hemostasis [12]. Major attempts have been made in recent decades to establish alternative and trustworthy assessments of the antiplatelet effect of aspirin due to the major challenges in standardizing this sort of test. In evaluating the aspirin effect, each of these suggested approaches showed considerable variation and a weak association with one another [13, 14]. More significantly, no trustworthy clinical evidence of any of these tests' predictive validity or association with clinically meaningful outcomes has been found to date [15]. It is important to note, that aspirin-associated hypocoagulation cannot be shown by non-specific viscoelastic tests such as thromboelastography or rotational thromboelastometry, which were created for an integrated evaluation of blood clot formation. This behaviour can also be viewed as the main risk factor for the formation of dense clots in the presence of aspirin [16].
Impact of aspirin on bleeding risk in non-neurosurgical patients
There is limited clinical evidence regarding the continuation or discontinuation of aspirin in surgical patients. However, interactions between aspirin, NSAIDs, and perioperative anticoagulants have raised concerns about the design and outcomes of related clinical trials. [17]. According to current guidelines on perioperative bleeding, "aspirin should not be withdrawn peri-operatively unless the risk of bleeding exceeds the thrombotic risk from withholding the drug," [18]. However, as previously said, neurosurgical patients require a distinct and individualized approach to care.
In Brain surgery and aspirin related studies, Rahman et al. [7] concluded that brain tumour surgeries were not associated with an increased haemorrhagic risk with patients who used low-dose aspirin before surgery. McGaul [19], mentioned perioperative aspirin related complications may increase risk in dental surgery but the results of this study cannot directly correlate with neurosurgical procedures outcome. Another case report by Kulikov et al. [20] identified that aspirin was not associated with increased bleeding risk. Another study found that haemorrhagic risk was the same in aspirin or non- aspirin groups [21]. Tonchev N, et al. [22], explained that “In patients with a high cardiovascular and cerebrovascular risk, low-dose ASA can be safely sustained after brain tumour surgery, and its perioperative use has not been linked to an increased rate of haemorrhagic complications after pituitary adenoma surgery”. While Ma Y et al. [23] explained that antiplatelet therapy did not increase the risk of haemorrhage and improved outcomes after vascular revascularization procedures. Bianconi et al. [24] described intracranial haemorrhage after intracranial aneurysm clipping was more frequent in those patients who were using antiplatelet therapy. Dasenbrock et al. [25] explained in their study that the use of aspirin was not associated with an increased risk of postoperative haemorrhage in vascular surgery patients. Florez et al. [26] also presented the same finding and clearly explained that aspirin didn’t increase the chance of bleeding in the intraoperative or preoperative period.
In spinal surgery patients, Zhang et al. [6] stated that there was no difference in perioperative complications between aspirin continuation and discontinuation. Similarly, Zian et al. [29] and Suk-Bong et al. [30] found that continued aspirin administration did not have an increased risk for bleeding. Meta-analysis ASA (Aspirin)-continuing group ASA-discontinuing group. Cuellar et al. [27] compared three groups—patients who never used aspirin, those who discontinued aspirin preoperatively, and those who continued aspirin therapy—and observed no differences in perioperative complications or clinical outcomes. In another study, Ju et al. [28] concluded that there was no association between low-dose ASA continuations with increased blood loss.
Balancing the risk
The clinical data presented reflect a lack of trustworthy evidence about clinical decision-making regarding the continuation or cessation of aspirin use during the perioperative phase in patients slated for elective neurosurgery procedures.
During surgery, the coagulation process gets triggered, (also known as blood clotting mechanism) which is a crucial mechanism that stops bleeding from incision site or dissection area automatically. The formation of a clot is created by various mechanisms including platelets, plasma proteins and various factors. Due to the involvement of various players in coagulation process, strength of aspirin’s anticoagulation effect is unclear.
Variability in clinical practice is caused by inconsistent clinical data [31, 32]. Furthermore, there is inconsistency among the standards on this matter.
Guidelines on perioperative bleeding management from the European Society of Anaesthesiology and Intensive Care, for example, state that "intracranial surgery can be safely performed in the presence of low-dose aspirin." However, if aspirin withdrawal before surgery is taken into consideration, the time from the last medication intake to the intervention is three days. Nonetheless, a longer gap (5 – 7 days) can be taken into consideration for invasive treatments that have a high risk of bleeding [18]. Compared to the ambiguous ESC recommendations recommendation of at least 7 days of withdrawal, this period is substantially shorter [1].
A framework for such decision-making is not precisely defined. However, it is essential that multidisciplinary consultation among neurosurgeons, anaesthesiologists, cardiologists informs the choice to continue or discontinue taking aspirin in a given situation. It may include the estimated risk of blood loss consequences from prolonged bleeding, the risk of postoperative ischemia complications due to aspirin cessation, and the risk of delaying surgery. Non-specific variables including preoperative anaemia, renal dysfunction, chronic liver illness, metabolic disorders, etc., should also be considered when assessing a person's risk of bleeding [18]. Before having surgery, such defects should be fixed, if at all feasible.
It should be considered that the antiplatelet effect of aspirin may exacerbate high estimated blood loss. This is especially crucial in situations when neoplasms—tissues with aberrant vascular wall structure—will require surgical manipulation inside the tissues. For spinal and cerebrovascular surgery, this risk is generally lower. However, in patients with high cardiac risk (history of myocardial infarction, coronary stenting, unstable angina, etc., which are among the most common indications for chronic aspirin use), the risk of thrombotic complications may exceed the risk of bleeding. In some situations, continuing aspirin therapy might yield better outcomes.
Additionally, treating patients who may suffer major repercussions from a delay in surgical intervention is often necessary in neurosurgical practice (e.g., seizures in patients with intracranial masses, increasing neurologic loss brought on by the mass effect and intracranial haemorrhage from a brain lesion, etc.). The risk-benefit ratio of stopping aspirin in these situations is still unknown. The ESC's suggestion to stop aspirin may understate the dangers and consequences of delaying surgery.
Conclusion
The discontinuation of aspirin before neurosurgical procedures remains a contentious clinical issue. Neurosurgical patients exhibit a wide range of bleeding risks during surgery, necessitating individualized risk assessments.
However, present neurosurgical treatment protocol, for the all preoperative patients, aspirin cessation is currently advised and followed. These protocols encourage doctors to make the same therapeutic choices regardless. Future research should focus on developing evidence-based guidelines to support logical and individualized clinical decision-making in this area.
Disclosure
Conflict of interest
The authors declare no conflicts of interest and no personal financial interest in the preparation of this article.
Funding
Not applicable
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