A Cause for a PAUSE: Evaluating a Standardized Perioperative DOAC Management Protocol

Author(s)
Maggie Faraj, PharmD
Candice Garwood, PharmD, BCPS, BCACP

Reviewed By
Kathryn Kiser, PharmD, BCACP
Erin Van Meter, PharmD, BCACP

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

The Problem

 

One in six patients with atrial fibrillation (AF), or an estimated six million patients worldwide, will require perioperative anticoagulant management.^1,2  Ambulatory care pharmacists commonly face the scenario where a patient taking a direct oral anticoagulant (DOAC) for AF requires an elective surgery or procedure. Best practices for periprocedural management of DOACs are unclear and current guidelines differ in their recommended approaches.³ A study evaluating a standardized approproach to the perioperative management of DOACs is clearly needed.⁴ There is increasing need for “anticoagulation stewardship”; the coordinated, efficient, and sustainable system-level initiatives designed to achieve optimal anticoagulant-related health outcomes and minimize avoidable adverse drug events.⁵ Having a simple, systematic periprocedural DOAC management protocol would align with implementation of anticoagulation stewardship initiatives. But would a straightforward protocol that is easily understood by clinicians and patients be safe and effective?

 

What’s Known

 

The perioperative management of DOAC regimens varies widely in clinical practice and currrent guidelines provide inconsistent management recommendations based on weak or no evidence. Moreover, studies to date are largely patient registries or retrospective subanalyses of randomized clinical trials.

 

Preoperative coagulation testing has been suggested to identify patients with an excessive residual anticoagulant level in whom a procedure perhaps should be delayed or the DOAC reversed. Such an approach would be problematic because it is not based on evidence.^6,7 Thus, a “time-based” interruption protocol that forgoes coagulation testing would be desirable.

 

What’s New

 

The objective of the PAUSE study was to investigate the safety of a standardized perioperative DOAC management strategy.⁸ PAUSE was a prospective cohort study conducted at 23 sites in Canada, the United States, and Europe. Patients were screened from August 1, 2014 through July 31, 2018 and included if they had AF; were 18 years of age or older; were long-term users of apixaban, dabigatran, or rivaroxaban; were scheduled for an elective surgery or procedure; and could adhere to the DOAC therapy interruption protocol. They were excluded if they fit 1 or more of the following criteria: Creatinine clearance (CrCl) level less than 25 mL/min for apixaban users or CrCl level less than 30 mL/min for dabigatran or rivaroxaban users, cognitive impairment or psychiatric illness, or had more than 1 procedure planned within 30 days. Before the procedure, patients were categorized as having a high- or low–bleeding-risk procedure.

 

Based on their pharmacokinetic profiles, DOAC therapy was omitted for 1 day (3-5 half-lives) before a low–bleeding-risk procedure and 2 days (over 5 half lives) before a high–bleeding-risk procedure (see Table 1). Patients using dabigatran with a CrCl level less than 50 mL/min had a longer interruption interval to account for renal clearance of dabigatran. The residual anticoagulant level just before the procedure was measured by DOAC-specific anti–factor Xa assays for apixaban and rivaroxaban as well as by the dilute thrombin time (dTT) for dabigatran but these results were not available to the clinicians managing the patients during the study. After the operation, DOAC regimens were resumed 1 day after a low–bleeding risk procedure and 2 to 3 days after a high– bleeding-risk procedure, provided that hemostasis was achieved.

 

Table 1: Perioperative DOAC Management Protocol

DOAC	Surgical Procedure- Bleeding Risk	Preoperative DOAC Interruption Schedule					✘	Postoperative DOAC Resumption Schedule
		Day  -5	Day   -4	Day  -3	Day   -2	Day   -1	P R O C E D R E	Day +1	Day +2	Day +3	Day +4
Apixaban	High	✔︎	✔︎	✔︎	✘	✘		✘	✘/✔︎	✔︎	✔︎
	Low	✔︎	✔︎	✔︎	✔︎	✘		✔︎	✔︎	✔︎	✔︎
Dabigatran (CrCl ≥50 mL/min)	High	✔︎	✔︎	✔︎	✘	✘		✘	✘/✔︎	✔︎	✔︎
	Low	✔︎	✔︎	✔︎	✔︎	✘		✔︎	✔︎	✔︎	✔︎
Dabigatran (CrCl <50 mL/min)	High	✔︎	✘	✘	✘	✘		✘	✘/✔︎	✔︎	✔︎
	Low	✔︎	✔︎	✔︎	✘	✘		✔︎	✔︎	✔︎	✔︎
Rivaroxaban	High	✔︎	✔︎	✔︎	✘	✘		✘	✘/✔︎	✔︎	✔︎
	Low	✔︎	✔︎	✔︎	✔︎	✘		✔︎	✔︎	✔︎	✔︎

✔︎: DOAC was taken on this day; ✘: DOAC was not taken on this day; ✘/✔︎: flexibility in the timing of DOAC resumption after a procedure.

 

The primary outcomes were major bleeding and arterial thromboembolism (ischemic stroke, transient ischemic attack, and systemic embolism). Secondary outcomes included clinically relevant nonmajor bleeding, minor bleeding, death, myocardial infarction, deep vein thrombosis, pulmonary embolism, and catheter-associated venous or arterial thrombosis. Safety was defined as a perioperative major bleeding rate of 1.0% (80% power to exclude 2%) and risk of arterial thromboembolism of 0.5% (80% power to exclude 1.5%). The required sample size was 987 patients per DOAC agent, which provided 80% power at the 5% significance level (one sided). Study outcomes were assessed starting on the day of the first held DOAC dose until 30 days after the operation. Patients had scheduled weekly telephone follow-up and additional clinic visits as needed to document clinical outcomes.

 

Slightly more than 3000 patients were enrolled and included in the per-protocol analysis: 1257 (41.8%) in the apixaban cohort, 668 (22.2%) in the dabigatran cohort, and 1082 (36.0%) in the rivaroxaban cohort. Patients in the three DOAC groups had similar baseline characteristics (See Table 2).

 

Table 2: Baseline Patient Characteristics

Variable	Apixaban (n= 1257)	Dabigatran (n= 668)	Rivaroxaban (n= 1082)
Age, mean (SD), y	73.1	72.4	72.0
Male	64%	68.6%	67%
BMI, mean (SD)	29.5	30.2	29.8
Race/ethnicity, white	95.8%	97.9%	96.6%
Risk stratification score, mean (SD)
CHA2DS2-VA-Sc	3.5	3.5	3.3
Modified HAS-BLED	2	1.9	1.8
Medical condition
Congestive heart failure	19.3%	16.6%	12.9%
Hypertension	74.2%	75.4%	72.5%
Diabetes	26.8%	27.7%	25.2%
Coronary Artery Disease	18.5%	16.9%	16.4%
Prior TIA or Stroke	17.1	23.5	16.2
Concurrent Medication use
Aspirin	12.4%	14.7%	9.1%
P2Y12 inhibitor	0.9%	1%	1%
Prodedure type
High bleeding risk	32.3%	34.1%	34.5%
Low bleeding risk	67.7%	65.9%	65.5%
Anesthesia type
General	32.6%	28.9%	35.5%
Neuraxial	8.2%	8.5%	6.5%

The simple standardized perioperative management strategy used in PAUSE was associated with low rates of perioperative major bleeding (<2%) and arterial thromboembolism (<1%). The rate of 30-day postoperative major bleeding was 1.35% (95% CI 0%-2.00%) in the apixaban cohort, 0.90% (95% CI 0%-1.73%) in the dabigatran cohort, and 1.85% (95% CI 0%-2.65%) in the rivaroxaban cohort.  Arterial thromboembolism occurred at a rate of 0.16% (95% CI 0%-0.48%) in the apixaban cohort, 0.60% (95% CI 0%-1.33%) in the dabigatran cohort, and 0.37% (95% CI 0%-0.82%) in the rivaroxaban cohort.  Major bleeding was also evaluated based upon procedural bleed risk (See Tables 3).  All events occurred postoperatively at a median of 2 days (0-6 days). A high proportion of patients (>90% overall; 98.8% of those at high bleeding risk) had a minimal or no residual anticoaguant level at the time of the procedure (< 50 ng/dL).

 

Table 3: Incidence of Major Bleeding by Procedure Bleeding Risk

Procedure- Bleed Risk	Apixaban (n= 1257)	Dabigatran (n= 668)	Rivaroxaban (n= 1082)
Low
30-d postoperative rate of major bleeding, % (95% Cl)	0.59 (0-1.20)	0.91 (0-2.01)	1.27 (0-2.17)
High
30-d postoperative rate of major bleeding, % (95% Cl)	2.96 (0-4.68)	0.88 (0-2.62)	2.95 (0-4.76)

Our Critical Appraisal

 

The PAUSE study addresses a common and important clinical scenario and establishes a “standard of care” for the perioperative management of DOAC-treated patients. The PAUSE management protocol was designed to be easily applied in everyday practice and can be applied across practice settings in real-world situations. It is likely that this study will be the cornerstone for future guidelines and institution-specific protocols for DOAC perioperative management.

 

There are some limitations to the PAUSE trial. First, the dabigatran cohort did not reach the expected sample size — none-the-less, bleeding rates did not exceed 2%. Second, the apixaban cohort and the rivaroxaban cohort were not able to exclude a 2% rate of major bleeding, as the confidence intervals touch or exceed 2. None of the cohorts were able to exclude a major bleeding rate of 2% in patients undergoing high-bleed risk procedures. The study did not include patients with VTE and did not include patients taking edoxaban – so it is unclear if these data should be generalized to these populations. Most patients included were white, and additional studies are needed in nonwhite populations – particularly in populations that are known to have high bleeding risks and altered DOAC pharmacokinetics, especially patients from Asian ancestaries. Additional studies are needed in patients receiving neuraxial anesthesia since only a small number of patients were included in this trial (n= 230). Use of nuraxial anesthesia carries a high risk for spinal hemotoma in an anticoagulated patient, which can have devastating consequences. Several anticoagulants carry a boxed warning for this reason. Lastly, the 50 ng/mL cut point used in this study to assess residual anticoagulant level has not been validated. Further study is needed to determine if there is a correlation between preoperative DOAC treatment levels and bleeding risk, particularly in patients undergoing a high-bleeding risk procedure and when neuroaxial anesthesia is required.

 

Given that patients developed major bleeding and arterial thromboembolism at a median of 2 days after therapy interruption, future studies should evaluate the safety and efficacy of resuming DOAC regimens sooner after the procedure but at a reduced dose.  Additional study surrounding the meaning and clinical application of DOAC level testing would also be useful as there may be a role for laboratory testing in patients who are at high risk of bleeding and those with impaired renal function.

 

The Bottom Line

 

The results of the PAUSE trial provide compeling evidence that a simple and a standardized perioperative management strategy without preoperative coagulation testing is associated with low rates of bleeding and arterial thromboembolism. This simple patient management strategy can be easily implemented in practice, and will advance anticoagulation stewardship efforts, by providing the shortest duration of DOAC therapy interruption before and after an invasive procedure, minimizing the risks for bleeding and thromboembolism.

 

The Key Points

• The PAUSE trial is the first prospective clinical trial to evaluate a standardized perioperative management protocol for patients with AF who use a DOAC. This protocol was associated with low rates of bleeding and stroke.
• The PAUSE approach to DOAC management is based on the pharmacokinetic properties of the medication, procedure-associated bleeding risk, and creatinine clearance levels.
• The routine use of coagulation measurements appears to be unnecessary — “time-based” interruption resulted in “safe” anticoagulation levels in nearly all patients.

FINAL NOTE:  This program will be available for recertification credit through the American Pharmacists Association (APhA) Ambulatory Care Review and Recertification Program.  To learn more, visit https://www.pharmacist.com/ambulatory-care-review-and-recertification-activities.