June 2020

Bleeding risk assessment for bedside and interventional radiology guided procedures: Consensus guidelines and beyond

Aditi Khandelwal MDCM FRCPC, Internal Medicine and Adult Hematology Fellow, Transfusion Medicine, University of Toronto & Canadian Blood Services

Assessment of patients for peri-procedural bleeding risk involves consideration of both the unique procedure related risk as well as their underlying condition, co-morbidities and medications. Practice standards were updated in 2019 with endorsement from Canadian Association for Interventional Radiology (CAIR)^1,2. This article will allow clinicians to apply the guidelines to their practice and identify individuals at risk of bleeding:

1. Determine bleeding risk associated with procedure and relevant laboratory parameters

2. Identify individuals at higher risk of bleeding due to an acquired or congenital bleeding diathesis

3. Minimize bleeding risk imparted by prescription and non-prescription medications

Procedure related risk of bleeding 

To assist with risk-stratification of interventional procedures, Table 1 provides a list with selected interventional radiology procedures informed by both Thrombosis Canada and CAIR^2,3.

Table 1: Risk stratification of common bedside or interventional radiology guided procedures^2,3

* see Table 2 for laboratory parameters suggested in individuals with liver disease

Role of laboratory testing 

For low-risk procedures, routine laboratory testing is not recommended, no discontinuation of anticoagulation is required, and no correction of INR is required. Thresholds for correction or transfusion are provided in Table 2^2,4 for individuals with and without liver disease.

Two special situations need further discussion:

1. Patients with liver dysfunction or cirrhosis have re-balanced physiological coagulation. Despite prolonged aPTT, PT and low fibrinogen or platelet counts, patients with liver dysfunction are not at an increased risk of bleeding. In fact, they are susceptible to thrombosis at a rate twice as high as the general population. Bleeding is rare in patients with chronic liver disease, and often unrelated to the abnormalities observed on laboratory testing, including platelet counts below 50 x 10⁹/L.

2. Neuraxial procedures are considered higher risk due to risk of severe neurologic impairment from spinal bleeding. Generally, experts recommend a safe platelet count over 70 x 10⁹/L². The ESA and British guidelines recommend an INR ≤1.4, which can usually be achieved by patients stopping their warfarin 5 days prior to planned procedure⁷. For patients undergoing neuraxial anesthesia, direct-oral anticoagulants (DOACs) should be held for 2 days prior to the procedure⁷. Use of reversal agents, such as vitamin K or prothrombin complex concentrates, should be based on an individual risk-benefit assessment.

Table 2: Laboratory parameters suggested by consensus guidelines for procedures in those with and without cirrhosis^2,4

The accepted indications for coagulation testing are presented in Table 3. Laboratory coagulation testing, especially  prothrombin time (PT), activated partial thromboplastin time (aPTT) and international normalized ratio (INR), were not designed nor validated to screen for hemostatic defects in unselected patients⁵. Hence, they do not provide an accurate and reliable assessment of the patient’s in vivo coagulation capacity and bleeding or thrombotic risk⁵. In fact, a normal PT/INR and aPTT test may impart a false sense of security, as bleeding disorders, for example vonWillebrand disease or platelet dysfunction, may not show any perturbations in routinely performed coagulation tests.

Table 3: Accepted indications for common coagulation tests^4,6

Identifying patients with bleeding disorders 

The guidelines recommend use of the HASBLED score to risk-stratify patients². The HASBLED score has been validated for assessment of bleeding risk for individuals prescribed anticoagulation for atrial fibrillation. Although it has not been studied for peri-procedural risk stratification, HASBLED score has been widely adopted. Table 4 presents an approach to bleeding risk assessment in those undergoing interventional radiology guided procedures.

A thorough history, guided by a validated bleeding assessment tool (BAT), helps identify individuals with possible underlying bleeding diathesis⁸. BATs are designed for use in an unselected population as screening for congenital bleeding disorders, such as vonWillebrand disease, the most common inherited bleeding disorder. On the MCMDM-1 BAT (reproduced in Figure 1), a score of ≥4 has a sensitivity of 100%, specificity of 87%,and a negative predictive value of 100% for diagnosis of vonWillebrand disease⁸. If there is a suspicion of underlying coagulopathy based on initial assessment, patients should be referred to a specialist and/or a Hemophilia Treatment Center for further assessment.

Table 4: Risk factors for bleeding and assessment of bleeding risk in individuals undergoing interventional radiology procedures^2,8

Figure 1: The scoring chart for condensed MCMDM-1 bleeding assessment tool reproduced from Bloody Easy Coagulation Simplified 2nd ed^8,9

Medications as a risk factor for bleeding 

A complete list of prescription medications, over the counter medications and herbal products should be obtained. The impact of herbal products on hemostasis is underappreciated¹⁰. For procedures with moderate to high bleeding risk, herbal medication should be stopped 7 – 14 days prior^10,11.

Table 5: Complementary and alternative medications known to cause increased bleeding^10,11

The Perioperative Anticoagulation Use for Surgery Evaluation (PAUSE) cohort study⁷ and the CAIR endorsed guidelines^1,2 have helped simplify the peri-procedural management for patients on DOACs, as shown in Table 6. Using this approach, the 30-day postoperative rate of major bleeding was below 2%⁷.

Table 6: Peri-procedural DOAC management based on recent evidence^2,7

Routine laboratory testing for measuring DOAC levels is not recommended. There are certain peri-procedural situations where coagulation testing, include PT/INR, aPTT, drug-specific anti-Xa level, thrombin time (TT) and diluted TT, may be helpful. When an urgent intervention associated with a high bleeding risk is required, an anti-factor Xa level or dilute thrombin time below 30 ng/mL is safe to proceed with the intervention¹². Situations where lab testing in patients on DOACs may be beneficial include¹²:

1. Need for urgent/emergent intervention where information on last dose of DOAC cannot be obtained

2. Need for urgent/emergent surgery when patient has taken DOAC within 24 hours

3. Severe renal failure in a patient on a DOAC awaiting intervention

Timing of discontinuation of other anticoagulants and antiplatelet medications is informed by balancing both the dose and indication with risk of bleeding². A general approach is shown in Table 7. If the patient has a high risk of thrombosis (recurrent thrombosis, recent venous thrombosis, atypical thrombosis, mechanical mitral valve etc), bridging may need to be discussed. These decisions should be made in collaboration with specialists managing anticoagulation. For patients with recent percutaneous cardiac intervention with stent placement, all non-urgent procedures should be postponed a minimum of 1 month.

Table 7: Management of other commonly used  anticoagulants and antiplatelets^2,3

Conclusion 

A careful history, judicious use of laboratory testing and a review of medications can help determine the bleeding risk of a patient. When combined with the risk associated with the procedure being offered, it can help identify those at increased risk of bleeding. Once identified, patients with higher risk of bleeding can benefit from correction of certain laboratory abnormalities, liberal use of tranexamic acid and timely discontinuation of dangerous medications. A multidisciplinary approach, with advice from a hematologist or transfusion specialist, can also be helpful to determine strategies to reduce bleeding.

References:

1. Davidson JC, Rahim S, Hanks SE et al. Society of interventional radiology consensus guidelines for the periprocedural management of thrombotic and bleeding risk in patients undergoing percutaneous image-guided interventions – Part I: review of anticoagulation agents and clinical considerations. J Vasc interv Radiol 2019; 30:1155-1167.

2. Patel IJ, Rahim S, Davidson JC et al. Society of interventional radiology consensus guidelines for the periprocedural management of thrombotic and bleeding risk in patients undergoing percutaneous image-guided interventions – Part II: recommendations. J Vasc interv Radiol 2019; 30:1155-1167.

3. Thrombosis Canada Clinical Guide. Perioperative Management of Antiplatelet Therapy. Last updated 2019/Feb 11 . Available at: https://thrombosiscanada.ca/clinicalguides/# (accessed 11 March, 2020).

4. Fralick M et al. Reduce unnecessary coagulation testing in the emergency department (REDUCED). BMJ Quality. 2017;6:u221651.w8161.

5. Levy JH, Szlam F, Wolberg AS et al. Clinical use of the activated partial thromboplastin time and prothrombin time for screening: a review of the literature and current guidelines for testing. Clin Lab Med. 2014; 34(3):453-77.

6. CAS and Choosing Wisely Canada. Anesthesiology – five things physicians and patients should question. Available at URL: https://choosingwiselycanada.org/anesthesiology/ (accessed March 11, 2020)

7. Douketis JD, Spyropoulos AC, Duncan J, et al. Perioperative Management of Patients With Atrial Fibrillation Receiving a Direct Oral Anticoagulant (PAUSE). JAMA Intern Med. 2019;179(11):1469-1478.

8. Bowman M, Mundell G, Grabell J et al. Generation and validation of the condensed MCMDM-1 bleeding questionnaire for von Willebrand disease. J Thromb Haemost 2008;6:2062-6.

9. Black L, Selby R, Brnjac E et al. Bloody easy coagulation simplified 2nd ed. ORBCoN Feb 2019. Available at URL: https://transfusionontario.org/documents/?cat=bloody_easy (Accessed 24 March, 2020).

10. Ang-Lee M, Moss J, Yuan CS. Herbal medicines and peri-operative care. JAMA. 2001;286(2):208-216.

11. Hodges PJ, Kam PC. The peri-operative implications of herbal medicines. Anaesthesia. 2002;57(9):889-99.

12. Cuker A et al. Laboratory measurement of the anticoagulant activity of the non‐vitamin K oral anticoagulants. J Am Coll Cardiol 2014;64(11):1128‐1139.