The Curbsiders podcast

#425 Perioperative Management of Antithrombotics with Dr. Poorvi Hardman

February 5, 2024 | By

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Get rid of those clots around anticoagulation and antiplatelet management

Join us for a review of the perioperative risk assessment of bleeding and clotting and how to manage each patient’s own antithrombotics. We are joined by Dr. Poorvi Hardman from Ohio State University

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Show Segments

  • Intro
  • Rapid Fire Questions/Picks of the Week
  • Case 1
  • Risk stratification of thromboembolism and bleeding
  • Review of types of surgeries and risk associated with surgical intervention
  • Utilizing scoring systems to aid decision making
  • Bridging
  • Considerations for VKAs, DOACs 
  • Pitfalls to bridging
  • Case 2
  • Aspirin Management
  • P2Y12 Management
  • Consultants
  • Outro

[ Perioperative Antithrombotics ] Pearls

  1. It is important to consider the  urgency, thromboembolic, and bleeding risk of the procedure when developing a perioperative plan for a patient’s anti-thrombotics. 
  2. As a general principle, bridging should be considered on a case by case basis–with high thromboembolic risk being the most important factor.
  3. Recent venous thromboembolism, thromboembolic stroke, new onset afib or new intracardiac thrombus are all indications to delay an elective procedure.
  4. In general, it is safe to resume antithrombotics after >24 hrs following a procedure, though it might be longer if the patient has a higher post-operative bleeding risk. 
  5. Favor continuing aspirin therapy, especially if the patient is on it for secondary prevention. 

Perioperative Anti-Thrombotics

General Approach to Anticoagulant Management

The management of perioperative antithrombotic medications can be challenging due to the variability in recommendations within the literature. Dr. Hardman recommends a step-wise approach when determining perioperative antithrombotic management plans. She suggests referring to the 2022 CHEST Clinical Practice Guidelines for Perioperative Management of Antithrombotic Therapy and the 2023 Annals of Internal Medicine review on Periprocedural Anticoagulation to assist with risk stratification and management. It is important to consider the following:

Procedure Type and Urgency

When a procedure is truly emergent, patients usually don’t have time to wait for antithrombotic wash out periods and must immediately proceed to the OR. In these cases, we may choose to use antithrombotic reversal agents to reduce the risk of procedural bleeding during high bleeding risk procedures. In the case of elective/non-emergent procedures, we have time to develop a management plan based on patient and procedure specific factors.

Bleeding Risk of Procedure

There are various resources available to help clinicians assess procedural bleeding risk. Table 2 from the 2022 CHEST guidelines (Douketis, 2022)  or Table 1 from the 2023 Annals of Internal Medicine Review (Parks, 2023) are helpful references. These tables stratify surgeries based on their bleeding risk profile. It is important to note that the estimated bleeding risk does not take into account any patient specific characteristics.

Thromboembolic Risk of Patient 

Table 1 from the CHEST guidelines (Douketis, 2022) and Table 4 from the Annals of Internal Medicine review (Parks, 2023) are helpful references when considering a patient’s risk of thromboembolism. These tables do not take into account the type or length of surgery which can also affect thromboembolic risk.

Risk Stratification

Dr. Hardman recommends stratifying patients into the following groups to help clinicians decide when interruption and bridging of anticoagulation is appropriate:

  • Low bleeding risk procedures – usually safe to continue anticoagulation.
  • Moderate/high bleeding risk AND moderate thromboembolic risk – usually safe to hold anticoagulation and forego bridging.
  • Moderate/high bleeding risk AND high thromboembolic risk – most patients require anticoagulant interruption and use of bridging therapy if they are taking vitamin K antagonists (VKAs).

For complex cases or when uncertainty remains despite the above stepwise approach, consider reaching out to consultants for assistance. The hematologists, cardiologists, and surgeons who have an established outpatient relationship with the patient can be helpful in creating  an appropriate perioperative antithrombotic management plan (expert opinion).

Scoring Systems

CHA2DS2VASc

This has classically been used to predict the risk of stroke in atrial fibrillation patients. Many experts consider high CHA2DS2VASc scores to be predictive of perioperative arterial thromboembolism. Patients should be considered high risk if there CHA2DS2VASc score is  ≥ 7 or if their score is 5-6 and they’ve had a recent thromboembolic stroke/transient ischemic attack (TIA) within 3 months (Douketis, 2022Parks, 2023).

HASBLED

This can be used in patients with atrial fibrillation to assess other patient factors that contribute to bleeding beyond simply the procedure specific bleeding risk. A score of ≥ 3 is considered to confer a high risk for bleeding (Pisters, 2010).

Bridging

Who to Bridge

In general, patients who are anticoagulated with VKAs and have high thromboembolic risk should receive bridging therapy to reduce perioperative thromboembolic events. It is important to remember that guidance for the use of bridging anticoagulation is variable in the current literature because of the lack of a consensus for what constitutes “high thromboembolic risk” (Douketis, 2022, Parks, 2023). Dr. Hardman prefers to use Table 4 from the 2023 Annals of Internal Medicine review article (Parks, 2023) which provides guidance for when to bridge patients with mechanical valves, atrial fibrillation, hypercoagulable states, and history of venous thromboembolism. She points out that each patient requires an individualized approach, and thromboembolic risk often needs to be considered on a case by case basis after considering a multitude of different patient and procedure specific factors.

It is also important to note that unless the timing of surgery is unknown, it is generally not necessary to bridge patients who are taking DOACs (Parks, 2023). Please refer to the hold times section listed below.

Choice of Bridging Agent

When bridging is necessary, either an unfractionated heparin (UFH) drip or low molecular weight heparin (LMWH) may be used. There are advantages and disadvantages to both:

Unfractionated Heparin

UFH has several benefits including: a quicker onset and offset, shorter hold time (6 hours). However, its downsides include: challenging pharmacokinetics, frequent lab draws for titration to therapeutic level, and a higher risk of bleeding compared to LMWH. 

Low Molecular Weight Heparin 

LMWH has several benefits including: easy to dose, and a lower risk of bleeding compared to UFH. However, its downsides include:  a required 24 hour hold prior to surgery, and limitation of use due to renal impairment when creatinine clearance drops below 30 mL/min. (Parks, 2023).

How to Bridge

In patients with an INR of 2-3, VKAs, such as warfarin, can usually be held 5 days prior to surgery. If the INR is >3, longer hold times may be necessary. When using LMWH, it can be started 36 hours after the last dose of the VKA and stopped 24 hours prior to surgery (if creatinine clearance > 50 mL/min). If creatinine clearance is between 30-50 mL/min, LMWH can still be used with the same start time parameters, but will need to be stopped 36 hours prior to procedure. When using UFH, it can be started once their INR has dropped below the lower level of their therapeutic goal, and stopped 6 hours prior to the procedure. If the bleeding risk is high, one could consider checking INR just prior to surgery and administering Vitamin K if INR >1.5. (Parks, 2023).

Anticoagulant Hold/Resumption Times

VKAs – Hold ≥5 days prior to surgery. Longer hold times can be considered when the starting INR is >3.

DOACs – These agents can usually be stopped 24-48 hours prior to the procedure with the exception of dabigatran which should be held for 2-4 days depending on bleeding risk and renal function. Lengthening hold times can be considered if patients have renal impairment or if they are receiving neuraxial anesthesia.

UFH – Hold 4-6 hours prior to surgery.

LMWH – Last dose should be 24 hours prior to surgery.

All of the above agents are generally safe to resume ≥ 24 hours after surgery in most cases. Extending the resumption time to 2-3 days can be considered for the DOACs if a patient has high postoperative bleeding risk (Douketis, 2022 and Parks, 2023).

When to Delay Elective Procedures

Dr. Hardman gave examples of when she would recommend delaying elective procedures in order to minimize recurrent thromboembolic events. 

If a patient has acute thromboembolic stroke/transient ischemic attack the risk of recurrent stroke is highest in the first 3 months following the event, and begins to level off after 6 months. It is preferable to wait at least 3 months after an acute stroke (expert opinion) for urgent surgeries, however, some sources recommend waiting 6 months if possible prior to undergoing surgery (Benesch, 2021). The territory and mechanism of stroke can also play a role, so reaching out to the patient’s neurologist is recommended (expert opinion). 

If a patient has a recent venous thromboembolism (VTE), then Dr. Hardman recommends waiting at least 1 month, but preferably 3 months if possible after an acute VTE. This is the period when VTE recurrence is highest (Douketis, 2000; Kearon and Hirsh, 1997). It is advisable to use bridging therapy during this time frame if surgery is unable to be delayed.

If a patient has new onset atrial fibrillation then consider getting an echocardiogram first to assess for valve function and cardiomyopathy which put patients at risk for thrombus formation (expert opinion).

If a patient has a new intracardiac thrombus then it is advisable to delay surgery until the thrombus has been adequately treated (expert opinion). 

Anticoagulant Reversal

When procedures are emergent, it may be necessary to reverse anticoagulant effects. Keep in mind that these reversal agents carry a prothrombotic risk, so they should only be used when there is a life threatening bleed or when a procedure is truly emergent. 4-factor prothrombin complex concentrates (PCC) and fresh frozen plasma (FFP) can be used when immediate reversal of anticoagulation is required. Their effects are quick, but transient. Some anticoagulants have specific reversal agents as well:

  • Vitamin K Antagonists – Oral or intravenous vitamin K can be used, but its INR lowering effect is significantly delayed (6-24hrs) compared to 4-factor PCC and FFP.
  • Dabigatran – Idracizumab is an oral thrombin inhibitor that can be used for dabigatran reversal. It has a quick onset of action and a prolonged duration compared to 4-factor PCC and FFP.
  • Rivaroxaban, Apixaban, Edoxaban – Andexanet Alfa is an option for factor Xa inhibitor reversal, however, its high cost limits its availability and use. Dr. Hardman suggests using 4-factor PCC for these agents. (Parks, 2023)

Antiplatelet Agent Management

Aspirin

Historically, clinicians often stopped aspirin perioperatively. This practice was based on the results of the 2014 Poise-2 study which showed that in patients undergoing non-cardiac surgery, aspirin continuation significantly increased the risk of major bleeding, but did not decrease the composite rate of death or nonfatal myocardial infarction. However, it should be noted that in the subgroup of patients who had coronary stents, the incidence of myocardial infarction did decrease with perioperative aspirin use (Devereaux, 2014). There were several limitations to this study, and further research has resulted in the CHEST guidelines now recommending aspirin continuation, rather than interruption, for patients undergoing surgery (Douketis, 2022). Dr. Hardman’s approach is to continue aspirin in most cases when it is being used for secondary prevention, except for neurosurgical procedures where you might be required to hold aspirin. Only hold aspirin for high bleeding risk procedures when it is being used for primary prevention (expert opinion).

Dual Antiplatelet Therapy

Perioperative management of P2Y12 inhibitors is generally a more complex issue because many patients take them in combination with aspirin to prevent coronary stent thrombosis. The ACC/AHA guidelines generally recommend continuing dual antiplatelet therapy (DAPT) for at least 1 month following placement of bare metal stents and for 6-12 months following drug eluting stents (ACC/AHA Guidelines, 2016). In patients undergoing elective surgeries who are on dual antiplatelet therapy (DAPT) after coronary stenting, the decision to continue or stop one of the agents is dependent on several factors including the timing of stent placement, type of stent (bare metal or drug eluting), stent location, and the number/length of stents placed.

The CHEST guidelines do provide recommendations regarding DAPT management perioperatively, however, they are only conditional recommendations based on very low certainty of evidence (Douketis, 2022). Dr. Hardman acknowledged that the risk of adverse cardiovascular outcomes is highest in the first 6-12 weeks after stent placement. She recommends waiting at least 6 weeks after bare metal stent placement, and 6 months after drug eluting stent placement before you consider holding P2Y12 inhibitors for surgical procedures (expert opinion).

Antiplatelet Hold Times (Douketis, 2022)

  • Aspirin: 7 days
  • Clopidogrel: 5 days
  • Ticagrelor: 3-5 days
  • Prasugrel: 7 days 

Links

  1. Blue Bell Ice Cream
  2. Beyonce–Renaissance World Tour
  3. What We Carry — Maya Shanbhag Lang

Goal

Listeners will develop a framework for managing perioperative antithrombotic therapy.

Learning objectives

After listening to this episode listeners will…  

  1. Assess perioperative thromboembolic and bleeding risks.
  2. Recognize the indications for bridging anticoagulation therapy.
  3. Appreciate the situations in which surgery must be delayed due to antithrombotic treatment.
  4. Develop a perioperative antithrombotic management strategy based on an individualized risk profile.
  5. Acknowledge when specialist assistance may be necessary to assist with developing an antithrombotic management plan.

Disclosures

Dr. Hardman reports no relevant financial disclosures. The Curbsiders report no relevant financial disclosures. 

Citation

Patel, J, Hardman, P, Amin, MA, Trubitt, ME. “#425 Perioperative Management of Antithrombotics with Dr. Poorvi Hardman”. The Curbsiders Internal Medicine Podcast. thecurbsiders.com/category/curbsiders-podcast Final publishing date February 5, 2024.

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Episode Credits

Written, produced and show notes by: Jaimie Patel MD
Infographic and Cover Art by: Caroline Coleman MD
Hosts: Monee Amin MD; Meredith Trubitt MD
Reviewer: Fatima Syed MD
Showrunners: Matthew Watto MD, FACP; Paul Williams MD, FACP
Technical Production: PodPaste
Guest: Poorvi Hardman MD

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