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. 

• A patient- and procedural-specific strategy is recommended when deciding whether to continue or discontinue ASA in the perioperative period for interventional pain procedures. Decision making should include an understanding of the reason for ASA utilization, the vascular anatomy surrounding the target area, the degree of invasiveness of the procedure, and the potential sequelae associated with perioperative bleeding.
• In addition, a complete review of the patient's medical record should occur to identify additional medications that may heighten ASA's anticoagulant effect (eg, selective serotonin norepinephrine reuptake inhibitors [SNRIs] and dipyridamole).
• If ASA is being taken for primary prophylaxis, ASA discontinuation is recommended for high-risk procedures in which there is a heightened risk of perioperative bleeding and sequelae. In addition, consideration should be given to the discontinuation of ASA for certain intermediate-risk procedures, including interlaminar cervical ESIs and stellate ganglion blocks, where specific anatomical configurations may increase the risk and consequences of procedural bleeding.
• When ASA is being utilized for primary prophylaxis, ASA may be discontinued for a longer period, 6 days, to ensure complete platelet functional recovery.
• In individuals utilizing ASA for secondary prophylaxis undergoing high-risk procedures, a shared assessment, risk stratification and management decision should involve the interventional pain physician, patient, and physician prescribing ASA. The risk of bleeding while continuing ASA needs to be weighed against the cardiovascular risks of stopping ASA. Documentation of decision making should occur. If a decision is made to discontinue chronic ASA therapy, the time of discontinuation should be determined individually.
• When performing elective pain procedures where there is either a high risk of potential bleeding and/or the possibility of significant sequelae in an individual taking ASA for secondary prophylaxis, ASA should be discontinued for a minimum of 6 days. In individuals taking ASA for secondary prophylaxis who are undergoing low- or medium-risk procedures for which a decision has been made to discontinue, the length of discontinuation can be shortened to 4 days in an effort to balance the risks of procedural bleeding and cardiovascular events. Zisman et al. demonstrated that in most ASA-treated patients platelet function recovers 4 days after drug discontinuation.

 

The decision to discontinue cilostazol or dipyridamole without ASA or combined with ASA should involve shared decision making between the interventional pain physician, patient, and prescribing physician.

• For high-risk procedures, cilostazol and dipyridamole without ASA should be discontinued 48 hours prior to performing the intervention.
• For intermediate- and low-risk procedures, cilostazol and dipyridamole without ASA do not need to be discontinued.
• The discontinuation length for dipyridamole combined with ASA should follow the ASA recommendations described previously for high-, intermediate-, and low-risk procedures. It has been suggested when dipyridamole is combined with ASA the risk of bleeding is increased.

 

• Currently, no consensus exists regarding the required duration for a spinal cord stimulator trial.
• The length of the trial should be sufficient to demonstrate improvement in pain control and allow prospective patients the ability to determine if they desire to progress forward to the implantation stage. Chincholkar et al, in a prospective trial examining 40 patients who underwent a spinal cord stimulator trial, demonstrated that a majority of patients are able to make a decision at a mean duration of 5.27 days. Furthermore, most individuals who had a successful trial arrived at a decision earlier than did those with an unsuccessful trial. In addition, Weinand et al. did not demonstrate improvement in outcomes with a prolonged trial. In this study, individuals either had an acute (15 minute intraoperative) or prolonged (5-day) SCS screening trial. Both the acute and prolonged SCS screening had equivalent predictive values for successful long-term SCS pain control.
• Because a platelet rebound phenomenon may occur with the discontinuation of ASA, and the time interval between ASA discontinuation and the occurrence of an acute cardiovascular event is in the range of 8 to 14 days, in individuals taking ASA for secondary prevention it is recommended that the length of the trial be minimized with a risk-benefit ratio considered for adequate trialing versus the possibility of cardiovascular sequelae.
• The Neurostimulation Appropriateness Consensus Committee recommendations formed by the International Neuromodulation Society also published specific measures to reduce the risk of bleeding and neurological injury secondary to impairment of coagulation in the setting of implantable neurostimulation devices in the spine, brain, and periphery. These recommendations are aligned with the recommendations published here.

 

• Because NSAIDs are not essential for cardiovascular protection, for high-risk procedures we recommend withholding these drugs for 24 hours after the procedure.
• For elective pain procedures associated with a high risk of bleeding complications, ASA can be resumed 24 hours after the procedure if required for secondary prevention.
• For primary prevention, ASA should not be restarted for at least 24 hours following high-risk procedures and specific intermediaterisk procedures, including interlaminar cervical ESIs and stellate ganglion blocks, where specific anatomical configurations may increase the risk and consequences of procedural bleeding. We recommend a delay because ASA rapidly and significantly affects platelet function after ingestion. Aspirin also influences thrombus stability and fibrinolysis. Clot stabilization probably typically occurs at 8 hours.

 

• We recommend a 5-half-life, or 4-day, interval discontinuation of fondaparinux before medium- and high-risk pain procedures.
• For low-risk procedures, a shared assessment, risk stratification, and management decision in conjunction with treating physician(s) should guide whether fondaparinux should be discontinued. If a more conservative approach is needed, then 2-half-life, or 2-day, interval is probably adequate.
• For low-risk procedures, we recommend an interval of 6 hours before fondaparinux is resumed. For intermediate- and high-risk surgical pain procedures, then a 24-hour delay is suggested. This is in view of the short onset of the effect of fondaparinux.

 

• Vitamin E at doses greater than 400 IU daily may require caution when performing high-risk procedures. Cessation timing should be similar to other drugs whose effects on platelet activity, such as ASA, are considered.
• Although fish oil effects remain unlikely to be major sources of bleeding, caution also suggests they be treated similar to other antiplatelet agents with 6-day stoppage prior to high-risk procedures, such as spinal cord or dorsal root ganglion stimulation.
• Unless history suggests other sources of bleeding, low- and intermediate-risk procedures likely require no change in fish oil consumption at normal daily doses (~1000 mg/d).

 

• We recommended 5-day discontinuation of pentosan polysulfate sodium prior to intermediate- and high-risk procedures.
• Pentosan polysulfate sodium can be resumed 24 hours after the conclusion of the procedure.