Interventional Spine and Pain Procedures in Patients on Antiplatelet and Anticoagulant Medications

The ASRA and European regional guidelines recommend that central neuraxial blocks may be performed in individuals utilizing ASA or NSAIDs. The Scandinavian guidelines for the performance of central neuraxial blocks in individuals utilizing ASA based their recommendations on the indication for ASA utilization and the daily dose. In individuals taking ASA for secondary prevention, a shorter discontinuation time of 12 hours was recommended. For individuals not using ASA for secondary prevention, the discontinuation time is 3 days unless the dose is greater than 1 g/d, for which the discontinuation time is extended to 1 week. For NSAIDs, the Scandinavian guidelines recommendations are guided by the specific half-life for each drug.
Data specifically defining the risk of bleeding with interventional pain medicine procedures with NSAID continuation remain limited since the first publication. Recently, small retrospective reviews evaluating bleeding complications in patients undergoing specific interventional pain procedures including joint injections, facet procedures, ESIs, percutaneous spinal cord stimulator trials and implantations, celiac plexus blocks, and intrathecal drug delivery systems have been published. Unfortunately, based on the inherent limitations of retrospective analyses and the small number of patients receiving NSAIDs, the ability to draw clinical conclusions and imply the safe performance of these interventional pain procedures while continuing NSAIDs and ASA is limited. Bleeding complications in individuals undergoing percutaneous spinal cord stimulator trial implantations were examined in 101 patients who had continued NSAIDs. In this retrospective review, only 48 patients were taking ASA, and 53 patients were taking NSAIDs. Patients were documented as taking ASA and NSAIDs if a dose was taken within 7 days of the procedure. A 7-day discontinuation time frame is an extended period for ASA and NSAIDs discontinuation based on the pharmacokinetics of the drugs. Many of these drugs can be stopped within 1 to 2 days, and the patient would not be expected to have any coagulation deficits or platelet deficiencies. Endres et al. examined bleeding complications in 4766 interventional pain procedures for which anticoagulants were continued. A majority of the procedures for which the anticoagulants were continued were for medial branch blocks (2074 patients), transforaminal ESIs (1633 patients), and trigger point injections (456 patients). In this analysis of 4766 interventional pain procedures for which anticoagulants were continued, only 60 patients continued ASA, for which more than 50% of the patients included those who underwent MBNBs. In addition, no interlaminar ESIs were performed with ASA. Therefore, significant limitations exist with the ability to declare safety when performing ESIs via the interlaminar approach while continuing ASA and NSAIDs. In this retrospective analysis, the sample sizes were small, and therefore, meaningful confidence intervals (CIs) around the observed prevalence for bleeding complications could not be provided. In addition because of the small sample size, procedures were not stratified according to cervical, thoracic, and lumbar segment levels. Therefore, it is unknown how many individuals had lumbar versus cervical procedures. For the MBNB patients, a large percentage of patients continued warfarin (1090/2074) and clopidogrel (890/2074). In order to fully determine the risk of continuing NSAIDs and ASA for specific pain procedures, larger numbers are required.
Aspirin has been identified as an important risk factor for postoperative bleeding and the development of hematomas including epidural hematomas in other surgical fields. Furthermore, the use of low-dose ASA before spine surgery, even when discontinued for at least 7 days, has been suggested to lead to further blood drainage after surgery. In an extensive review, low-dose ASA has also been shown to increase the rate of bleeding complications by a factor of 1.5 (median; interquartile range, 1.0–2.5). The baseline risk of bleeding varied based on surgical type (cataract surgery vs transurethral prostatectomy).
Bleeding complications also occur after the performance of interventional pain procedures. Spinal hematoma is a rare complication that has been associated with spinal cord stimulator trials, implants with percutaneously placed cylindrical leads and laminotomy-placed paddle leads, lead migration, revisions, and lead removal. Aspirin and NSAIDs have been suggested as a risk factor in some of the cases. Case reports of subdural hematomas following spinal anesthesia have also questioned ASA's continuation prior to a spinal anesthetic. In addition, spinal hematomas have occurred after cervical ESIs in individuals taking non-ASA NSAIDs. Other studies examining the performance of lumbar epidurals for pregnancy have not demonstrated an increased risk of bleeding complications with ASA. The CLASP (Collaborative Low-Dose Aspirin Study in Pregnancy) did not show an increase in bleeding complications when performing epidurals for pregnancy in individuals taking 60 mg of enteric-coated ASA daily.
Moreover, patients' comorbidities should be evaluated, as this may have a great impact on bleeding tendency. Specifically, renal dysfunction, including nephrotic syndrome, reduces NSAIDs' binding to plasma proteins, which can result in a larger volume of distribution and increased drug concentrations within tissues. Renal dysfunction can also prolong elimination half-life. Hepatic dysfunction may result in hypoalbuminemia and altered NSAID metabolism. Furthermore, alcohol and other pharmacological agents may potentiate the effects of both ASA and nonASA NSAIDs.