Peri-operative anticoagulation interruption thresholds: NICE vs BSHT vs ESAIC (2025)

Why this threshold matters

Clear thresholds help clinicians answer "when do I act?" for anticoagulation (peri-operative), aligning expectations between NICE, BSHT, and ESAIC. Use this side-by-side view to decide when to refer, escalate, monitor, or initiate treatment.

Clinical Context

Peri-operative anticoagulation management affects approximately 1 in 50 patients undergoing surgery annually in the UK, making this one of the most common clinical challenges in preoperative assessment. The key clinical dilemma involves balancing thrombotic risk against bleeding risk - interrupting anticoagulation too aggressively increases stroke and VTE risk, while insufficient interruption raises surgical bleeding complications.

Approximately 10-15% of surgical patients require formal anticoagulation interruption protocols. Getting these thresholds wrong can lead to serious harm: insufficient interruption causes major bleeding in 3-5% of cases, while excessive interruption increases thrombotic events by 2-4 fold. The mortality difference between optimal and poor management approaches 1-2% in high-risk populations.

NICE provides a comprehensive evidence-based approach focusing on standardized risk assessment, BSHT emphasizes individualized haematological risk stratification with specialist input, while ESAIC contributes the anaesthetist's perspective on practical peri-operative management and bleeding complications. Understanding these philosophical differences helps clinicians determine which guidance best suits their patient population and clinical setting.

Guideline Scope and Authority

Practical implications: Use NICE as the default standard for most secondary care patients, particularly when following standardized pathways. BSHT provides crucial input for complex haematological cases or when specialist review is available. ESAIC guides practical anaesthesia decisions and immediate peri-operative management. Cross-reference between guidelines when managing high-risk patients or when local protocols incorporate multiple perspectives.

Guideline comparison

Core Threshold Definitions

When to Monitor/Act - Detailed Intervals

NICE Approach: NICE recommends structured monitoring intervals beginning 7 days preoperatively. Assess bleeding and thrombotic risk using validated tools at initial assessment, repeat risk assessment 48 hours pre-op, and conduct final checks 24 hours before surgery. Postoperatively, monitor haemostasis every 12 hours for 48 hours, then transition to daily assessment. Special populations: elderly patients require more frequent INR checks (every 48 hours during warfarin interruption), while renal impairment patients need daily CrCl assessment during DOAC interruption.

BSHT Approach: BSHT emphasizes continuous risk assessment rather than fixed intervals. Begin monitoring 10-14 days preoperatively for complex cases. Key differences from NICE include daily thrombotic risk reassessment during interruption and more frequent bleeding parameter checks (every 6-8 hours postoperatively in high-risk patients). BSHT uniquely recommends platelet function testing in patients on antiplatelet combinations and suggests D-dimer trending during interruption for high thrombotic risk patients.

ESAIC Approach: ESAIC focuses on intensive peri-operative monitoring with anaesthesia-specific triggers. Monitoring begins 24-48 hours preoperatively with emphasis on point-of-care coagulation testing. Key differences: ESAIC recommends thromboelastography (TEG) or rotational thromboelastometry (ROTEM) for major surgery, suggests 4-hourly neurological assessments during bridging therapy for mechanical heart valve patients, and mandates 2-hourly surgical site checks postoperatively. ESAIC uniquely incorporates temperature and acid-base status into bleeding risk assessment.

Escalation Triggers / "When to Refer"

Clinical Scenarios

Scenario 1: Elderly Patient with AF Undergoing Hip Replacement

Patient: 78-year-old female with paroxysmal AF on apixaban, CrCl 35ml/min, scheduled for elective total hip replacement. CHA₂DS₂-VASc 4, HAS-BLED 2.

Analysis: NICE would recommend apixaban interruption 48 hours pre-op (standard risk), LMWH bridging starting 36 hours after last dose, stopping 24 hours pre-op, restarting 48-72 hours post-op. BSHT would individualize with possible 72-hour interruption given borderline renal function, earlier bridging (24 hours), and consider earlier restart (24 hours) if bleeding controlled. ESAIC would opt for 24-hour interruption with aggressive bridging and aim for 24-hour restart. The NICE approach provides the safest balance for this elderly patient with moderate renal impairment.

Scenario 2: Mechanical Valve Patient Needing Emergency Surgery

Patient: 45-year-old male with mechanical mitral valve on warfarin (INR 2.8) requiring emergency laparotomy for perforated diverticulitis.

Analysis: NICE recommends delay if possible, vitamin K reversal, and discuss with cardiology/haematology. BSHT mandates immediate haematology input for prothrombin complex concentrate (PCC) reversal and inpatient bridging. ESAIC focuses on immediate reversal with PCC, proceeding to surgery with anaesthesia managing bleeding risk, and early postoperative restart. The ESAIC approach is most appropriate for this emergency scenario where surgical delay carries greater risk than bleeding complications.

Risk Prediction and Decision Tools

Several validated tools assist peri-operative anticoagulation decisions. The CHA₂DS₂-VASc score predicts stroke risk during interruption - all three bodies recommend using this for thrombotic risk assessment. NICE emphasizes the HAS-BLED score for bleeding risk prediction, while BSHT prefers the ORBIT score for major bleeding risk. ESAIC incorporates the Surgical APGAR score for intraoperative bleeding risk assessment.

For practical application: Calculate CHA₂DS₂-VASc during preoperative assessment - scores ≥4 suggest higher thrombotic risk during interruption. Use HAS-BLED scores ≥3 to identify patients requiring more cautious interruption protocols. The ORBIT score provides additional granularity for major bleeding prediction, particularly useful when BSHT guidance is followed. ESAIC's use of Surgical APGAR helps anaesthetists make real-time decisions about reversal and restart timing.

Common Pitfalls

1. Over-interruption in elderly patients: Excessive anticoagulation interruption increases stroke risk disproportionately in elderly AF patients. Consequence: preventable cerebrovascular events.
2. Under-assessment of renal function: Failing to calculate CrCl using Cockcroft-Gault rather than relying on eGFR leads to inappropriate DOAC interruption times. Consequence: prolonged anticoagulant effect or premature restart.
3. Ignoring drug half-life differences: Treating all DOACs identically despite varying elimination half-lives (apixaban vs dabigatran). Consequence: suboptimal interruption timing.
4. Delaying restart in low-bleed-risk surgery: Unnecessarily postponing anticoagulation restart after minor procedures increases thrombotic risk. Consequence: VTE and stroke events.
5. Missing mechanical valve specifics: Failing to recognize that mechanical mitral valves require more aggressive bridging than aortic valves. Consequence: valve thrombosis.
6. Overlooking antiplatelet interactions: Not adjusting interruption protocols for patients on combined anticoagulant and antiplatelet therapy. Consequence: either excessive bleeding or thrombotic events.
7. Poor communication between teams: Inadequate handover between preoperative, operative, and postoperative teams regarding interruption plans. Consequence: protocol deviations and adverse events.

Practical Takeaways