Perioperative & Surgical Care

Preoperative anticoagulation management

Clinical Overview and When to Suspect Bleeding/Thrombotic Risk Perioperatively

— Warfarin (target INR 2–3 or 2.5–3.5 for mechanical mitral valves)

— DOACs: apixaban, rivaroxaban, dabigatran, edoxaban

— Parenteral: UFH, LMWH (enoxaparin, dalteparin)

— Antiplatelets often co-managed: aspirin, clopidogrel, ticagrelor, prasugrel

— Atrial fibrillation (CHA₂DS₂-VASc-based stratification)

— Mechanical heart valve (valve type + position + risk factors)

— VTE (timing from index event is critical — <3 mo = high risk)

— Patient on warfarin/DOAC scheduled for surgery, colonoscopy with planned polypectomy, dental extraction, cataract surgery, joint injection, or neuraxial anesthesia

— Acute trauma or emergency surgery in anticoagulated patient

— New AF discovered preoperatively

— Recent stent (DES <6 mo, BMS <1 mo) needing non-cardiac surgery

— When to stop the drug (depends on half-life and CrCl for DOACs)

— Whether to bridge with parenteral anticoagulation (warfarin only — never bridge DOACs)

— When to resume (procedural hemostasis and bleeding risk dictate)

Board pearl: The 2022 ACCP guidelines and BRIDGE trial fundamentally shifted practice — most AF patients on warfarin do NOT need bridging, even with CHA₂DS₂-VASc up to 4–5, because bridging increases major bleeding without reducing thromboembolism. Reserve bridging for mechanical mitral valves, recent VTE/stroke (<3 mo), and CHA₂DS₂-VASc ≥7 or prior stroke on therapy.

Step 3 management: Always document the indication, target INR, last dose, renal function, and procedural bleeding risk in the preop note — this is the single most testable workflow item.

Core question: Every patient on chronic anticoagulation undergoing a procedure requires a structured decision: continue, hold, or bridge — balancing thromboembolic risk (off-drug) against procedural bleeding risk (on-drug).

Common anticoagulants encountered:

Three indications drive 90% of cases:

When to suspect a perioperative anticoagulation problem:

Framework — three timing decisions:

Presentation Patterns and Key History

— "70-year-old on warfarin for AF (CHA₂DS₂-VASc 4) needs elective colonoscopy in 7 days"

— "65-year-old with bileaflet mechanical aortic valve, no other risk factors, scheduled for inguinal hernia repair"

— "55-year-old on apixaban for unprovoked PE 2 months ago, needs urgent cholecystectomy"

— "82-year-old on rivaroxaban with hip fracture from a fall — needs OR in 24 hours"

— Exact drug, dose, frequency, last dose taken (time and date)

— Indication and duration of therapy (cardioembolic vs venous)

— Prior thromboembolic events on or off therapy

— Bleeding history — GI bleed, intracranial hemorrhage, HAS-BLED features

— Renal function (CrCl) — critical for DOAC clearance timing

— Hepatic function — affects warfarin dosing and DOAC metabolism

— Concurrent antiplatelets — dual or triple therapy dramatically raises bleed risk

— Procedure type, urgency, and neuraxial plans

— Stroke or systemic embolism within 3 months → high thromboembolic risk

— Mechanical mitral valve, caged-ball valve, or any mechanical valve with AF/prior stroke → high risk

— VTE within 3 months, or active cancer-associated VTE

— Recent coronary stent: BMS <30 d, DES <6 mo (ideally <12 mo) → defer elective surgery

— Emergent (<6 h): no time to reverse pharmacologically — use reversal agents

— Urgent (6–24 h): partial reversal possible

— Time-sensitive (1–6 wk): hold drug appropriately

— Elective: full planning window

Key distinction: Do not confuse CHA₂DS₂-VASc (stroke risk in AF, drives anticoagulation decisions) with HAS-BLED (bleeding risk, never used to withhold anticoagulation but informs perioperative bridging caution). On Step 3, HAS-BLED ≥3 nudges away from bridging.

Board pearl: Always ask about herbal supplements — garlic, ginkgo, ginseng, vitamin E, fish oil all augment bleeding and should be stopped 7 days preop.

Typical preoperative consult scenarios:

History elements to extract every time:

Red-flag historical features:

Procedural urgency stratification:

Physical Exam Findings and Hemodynamic Assessment

— Vital signs: baseline BP, HR — uncontrolled hypertension worsens bleeding outcomes (defer elective surgery if SBP >180)

— Volume status: dehydration concentrates DOACs and impairs renal clearance

— Mucocutaneous exam: petechiae, ecchymoses, gingival bleeding suggest concurrent thrombocytopenia or supratherapeutic INR

— Cardiac exam: mechanical valve click (crisp = functioning), murmurs of valvular disease, irregularly irregular rhythm of AF

— Neurologic baseline: documented for any procedure where postop stroke or ICH is on the differential

— Active bleeding (epistaxis, melena, hematuria) → cancel elective surgery, work up

— Signs of recent stroke (subtle hemiparesis, dysarthria) → defer 3 months if at all possible

— Evidence of recent DVT (unilateral leg swelling) → image before proceeding

— Surgical site characteristics — vascularity, ability to achieve mechanical hemostasis

— Hypotension + anticoagulation + trauma → assume hemorrhage until proven otherwise

— Tachycardia disproportionate to obvious blood loss in a patient on beta-blocker masking → suspect occult bleed

— Mental status change on anticoagulant after fall → ICH protocol regardless of CT timing

— Document baseline lower extremity motor/sensory function before any neuraxial block

— Back exam for prior surgery, deformity that complicates needle placement

CCS pearl: In the CCS case of an anticoagulated patient with new neurologic findings post-procedure (especially after neuraxial anesthesia), order STAT MRI spine to rule out spinal/epidural hematoma — this is a surgical emergency with a narrow window (<8 h) for decompression to preserve function.

Board pearl: A patient on warfarin presenting with a "minor" head strike and any LOC, headache, or anticoagulation should get a non-contrast head CT even with a normal neuro exam — delayed ICH is well-described.

Preoperative exam priorities in anticoagulated patients:

Findings that change management:

Hemodynamic assessment for emergency reversal:

Neuraxial anesthesia exam considerations:

Diagnostic Workup — Initial Labs and Coagulation Testing

— CBC — platelet count (must be ≥50K for most surgery, ≥80–100K for neuraxial), Hgb baseline

— PT/INR — required for warfarin; INR should be <1.5 for most surgery, <1.3 for high-bleed-risk or neuraxial

— aPTT — for UFH monitoring; also screens for dabigatran effect (qualitative)

— BMP — creatinine and CrCl drive DOAC hold timing

— LFTs — hepatic dysfunction prolongs DOAC half-lives, affects warfarin

— Type and screen/crossmatch based on anticipated blood loss

— Anti-Xa level — quantifies apixaban, rivaroxaban, edoxaban, enoxaparin, UFH (chromogenic)

— Dilute thrombin time (dTT) or ecarin clotting time — quantifies dabigatran

— Thrombin time (TT) — exquisitely sensitive to dabigatran; normal TT effectively excludes clinically relevant dabigatran levels

— Standard PT/aPTT are insensitive to DOACs — a normal PT does NOT exclude DOAC effect

— Apixaban/rivaroxaban/edoxaban: hold 48 h before high-bleed-risk surgery, 24 h before low-bleed-risk

— Dabigatran (CrCl ≥50): hold 48 h high-risk, 24 h low-risk

— Dabigatran (CrCl 30–49): hold 96 h high-risk, 48 h low-risk

Step 3 management: Order INR within 24 h of surgery for warfarin patients — not the INR from last clinic visit 2 weeks ago. A "stale" INR is a classic Step 3 trap.

Board pearl: A normal PT/aPTT in a patient on a DOAC tells you almost nothing; you need drug-specific calibrated anti-Xa or dTT to confirm clearance before emergency surgery.

Baseline labs every anticoagulated preop patient needs:

Drug-specific assays (use when bleeding or emergent surgery):

Renal function and DOAC hold timing (key Step 3 numbers):

ECG: rate/rhythm baseline in AF patients, QT in patients on QT-prolonging perioperative meds

Pregnancy test for any woman of reproductive age — warfarin is teratogenic; DOACs are contraindicated in pregnancy

Advanced and Confirmatory Studies

— Useful in trauma, cardiac surgery, liver transplant — gives global hemostasis picture

— Identifies hyperfibrinolysis, platelet dysfunction, factor deficiency in real time

— Does NOT reliably detect therapeutic DOAC levels — a pitfall

— Calibrated anti-Xa with apixaban/rivaroxaban calibrator: <30 ng/mL generally safe for any procedure including neuraxial

— Dabigatran level <30 ng/mL similarly acceptable

— Order in: emergency surgery, renal failure with uncertain clearance, recent overdose, suspected bleeding from DOAC

— TTE/TEE for mechanical valve patients with new symptoms or before high-risk surgery — confirm valve function, exclude LA thrombus before cardioversion-type procedures

— Carotid duplex if recent TIA/stroke being considered for surgery

— Lower extremity duplex if signs of DVT

— V/Q or CTPA if PE recurrence suspected

— If proceeding to non-cardiac surgery, integrate RCRI and functional capacity (METs) — but do not delay surgery for testing that won't change management

— Coronary revascularization purely to "get through" non-cardiac surgery is not indicated (CARP trial)

— Cath records: stent type (DES vs BMS), location, date, prior in-stent thrombosis

— Confer with cardiology before stopping any antiplatelet within 6–12 months of DES

Key distinction: Anti-Xa calibrated for heparin vs calibrated for DOAC — same assay platform, different calibrator. Ordering the wrong one gives meaningless numbers. Always specify the agent.

Board pearl: Routine preoperative coagulation testing in unanticoagulated patients without bleeding history is not recommended (Choosing Wisely) — but in anticoagulated patients, targeted testing within 24 h is essential. Know the difference for question stems framed as "most appropriate next step."

TEG/ROTEM (viscoelastic testing):

DOAC-specific quantitative testing (if available):

Imaging for thromboembolic risk reassessment:

Stress testing / cardiac risk:

Stent-specific workup:

Risk Stratification — Thromboembolic vs Bleeding Risk Logic

— High (>10%/yr): mechanical mitral valve, any mechanical valve + stroke/TIA <6 mo, caged-ball or tilting-disc valve, CHA₂DS₂-VASc ≥7 or stroke <3 mo, VTE <3 mo, severe thrombophilia (antiphospholipid syndrome, protein C/S deficiency, homozygous factor V Leiden)

— Moderate (5–10%/yr): bileaflet mechanical aortic valve + ≥1 risk factor (AF, prior stroke, HTN, DM, CHF, age >75), CHA₂DS₂-VASc 5–6, VTE 3–12 mo, recurrent VTE, active cancer, heterozygous factor V Leiden

— Low (<5%/yr): bileaflet mechanical aortic valve without risk factors, CHA₂DS₂-VASc ≤4 without prior stroke, VTE >12 mo ago without other risk factors

— High: major cardiac/vascular/intracranial/spinal surgery, major cancer/orthopedic surgery, urologic surgery (TURP), bowel resection, kidney/liver/prostate biopsy, neuraxial anesthesia

— Low: cataract surgery, most dental procedures (extractions, cleanings), dermatologic procedures, diagnostic endoscopy without biopsy, pacemaker/ICD placement, joint/soft tissue injection

— Low bleed + low thrombo risk: often continue warfarin (dental, cataract, derm, EP device implant per BRUISE-CONTROL)

— High bleed + low thrombo: hold warfarin, no bridge

— High bleed + high thrombo: hold warfarin, bridge with LMWH

— High bleed + moderate thrombo: individualize — BRIDGE trial suggests no bridge for AF

— Hold based on CrCl and bleed risk — never bridge DOACs (short half-life is the "built-in bridge")

Board pearl: BRIDGE trial (2015): AF patients with mean CHA₂DS₂-VASc 2.3 — no bridging was non-inferior for thromboembolism (0.4% vs 0.3%) and reduced major bleeding (1.3% vs 3.2%). This is the most testable trial in this topic.

Step 3 management: Document the risk tier explicitly in the consult note — "high thromboembolic, high bleeding risk; plan: hold warfarin 5 d preop, bridge with therapeutic enoxaparin, last dose 24 h preop, resume warfarin POD 1, restart enoxaparin POD 2–3 once hemostasis assured."

Thromboembolic risk tiers (drives bridging decisions):

Procedural bleeding risk tiers:

Decision matrix (warfarin):

DOAC matrix:

Pharmacotherapy — Drug-Specific Hold and Resume Protocols

— Hold 5 days preop (typically goal INR <1.5 day of surgery)

— Check INR day before surgery; if 1.5–1.9, give vitamin K 1–2.5 mg PO

— Emergent reversal: 4-factor PCC (Kcentra) 25–50 units/kg + vitamin K 10 mg IV

— Resume 12–24 h postop at usual maintenance dose if hemostasis adequate; effect takes 5–7 days

— Low bleed risk: hold 24 h (CrCl ≥30); 48 h if CrCl <30

— High bleed risk: hold 48 h; 72 h if CrCl <30

— Reversal: andexanet alfa (specific) or 4-factor PCC (off-label)

— Resume 24 h low-bleed, 48–72 h high-bleed once hemostasis confirmed

— CrCl ≥50: hold 24 h low / 48 h high

— CrCl 30–49: hold 48 h low / 96 h high

— Reversal: idarucizumab (Praxbind) 5 g IV — specific monoclonal Fab; dialyzable

— Last dose 24 h before surgery (give half-dose if morning dose 24 h prior)

— Prophylactic dose can usually be given up to 12 h preop

— Resume 24 h postop for low-bleed, 48–72 h for high-bleed surgery

— Stop IV infusion 4–6 h preop; check aPTT

— SC UFH: hold 12 h preop

— Aspirin: continue for most surgery except intracranial/posterior eye/some prostate; mandatory continue if recent stent or secondary prevention with active CAD

— Clopidogrel: hold 5 days; ticagrelor 3–5 days; prasugrel 7 days

Board pearl: Never bridge DOACs — their short half-lives (8–17 h) make bridging pharmacologically unnecessary and clinically harmful. This is among the most-tested concepts.

Step 3 management: Write hold and resume orders with specific dates and times, not "hold 48 h" — ambiguity causes errors.

Warfarin:

Apixaban (Eliquis):

Rivaroxaban (Xarelto): same hold timing as apixaban; once-daily dosing

Edoxaban (Savaysa): hold ≥24 h low, ≥48 h high

Dabigatran (Pradaxa):

LMWH (therapeutic enoxaparin 1 mg/kg q12h):

UFH:

Antiplatelets:

Bridging Protocols, Reversal, and Procedural Considerations

— Stop warfarin day −5

— Start therapeutic enoxaparin 1 mg/kg SC q12h on day −3 (when INR drops below therapeutic)

— Last enoxaparin dose: 24 h before surgery, give half the usual dose as the final dose

— Restart enoxaparin 24 h postop (low bleed) or 48–72 h (high bleed)

— Restart warfarin POD 1 (evening) at usual dose

— Continue enoxaparin until INR therapeutic ×2 days (usually 5–7 days)

— IV infusion titrated to aPTT 1.5–2.5× control

— Stop 4–6 h preop

— Warfarin: vitamin K 10 mg IV (slow) + 4F-PCC 25–50 U/kg; FFP only if PCC unavailable

— Dabigatran: idarucizumab 5 g IV; HD if unavailable

— Apixaban/rivaroxaban: andexanet alfa (bolus + 2-h infusion) or 4F-PCC 50 U/kg

— Heparin/LMWH: protamine sulfate (full reversal for UFH; ~60% for LMWH)

— Antiplatelets: platelet transfusion (variable efficacy); desmopressin 0.3 mcg/kg

— Cataract surgery: continue warfarin and DOACs — minimal bleed risk

— Dental extractions: continue warfarin if INR <3.5; use local hemostatic measures (tranexamic acid mouthwash)

— Pacemaker/ICD (BRUISE-CONTROL): continue warfarin — less hematoma than bridging

— Colonoscopy with polypectomy: hold DOAC, polyp <1 cm low bleed risk

— Neuraxial anesthesia: DOAC hold 72 h preferred for spinal/epidural; LMWH 24 h (therapeutic) or 12 h (prophylactic)

CCS pearl: Anticoagulated patient with massive hemorrhage — order in parallel: type & cross, 2 large-bore IVs, reversal agent, transfusion, surgical/IR consult, ICU bed. Don't sequence what should be simultaneous.

Board pearl: Andexanet alfa transiently inhibits heparin — avoid heparin for ~12 h afterward, which complicates downstream surgery.

LMWH bridging protocol (when indicated):

UFH bridging (rare; only if LMWH contraindicated — CrCl <30, planned reversal need):

Reversal agents — match to drug:

Procedure-specific pearls:

Special Populations — Elderly and Renal/Hepatic Impairment

— Increased bleeding risk (falls, polypharmacy, low body weight, renal decline)

— Apixaban preferred DOAC — dose reduce to 2.5 mg BID if ≥2 of: age ≥80, weight ≤60 kg, Cr ≥1.5

— Avoid bridging where possible — bleeding harms outweigh thrombotic protection

— Frailty assessment and goals-of-care conversation before elective surgery

— Lower threshold for INR monitoring; smaller warfarin doses (often 2–3 mg/d)

— Apixaban: approved across CrCl spectrum including HD (limited data); dose reduce per criteria above

— Rivaroxaban: avoid if CrCl <15; reduce to 15 mg daily for AF if CrCl 15–50

— Edoxaban: contraindicated if CrCl >95 (paradox — reduced efficacy in AF) and avoid <15

— Dabigatran: avoid if CrCl <30; substantially renally cleared

— Hold times prolong with worsening renal function — recheck CrCl preop

— Warfarin or apixaban preferred for AF (apixaban increasingly used)

— Avoid dabigatran, rivaroxaban, edoxaban

— LMWH bridging risky — use UFH (titratable, reversible)

— Child-Pugh A: DOACs generally acceptable

— Child-Pugh B: avoid rivaroxaban; apixaban with caution

— Child-Pugh C: avoid all DOACs; warfarin difficult to manage (baseline INR elevation)

— Cirrhotic patients have rebalanced hemostasis — INR does NOT reflect bleeding risk; viscoelastic testing more useful

— BMI >40 or weight >120 kg: DOAC data limited — warfarin often preferred for VTE

— Low body weight: dose-reduce apixaban per criteria

Key distinction: Edoxaban is the only DOAC with an upper CrCl boundary for AF — it underdoses patients with hyperfiltration, increasing stroke risk. A favorite Step 3 trap.

Board pearl: In an 82-year-old on warfarin with CrCl 35 needing surgery — bridging is rarely indicated and the bleeding risk dominates. Defaulting to "bridge the elderly" is wrong.

Elderly (>75 years):

Renal impairment — DOAC adjustments:

Dialysis patients:

Hepatic impairment:

Weight extremes:

Special Populations — Pregnancy, Pediatrics, and Cancer

— Warfarin is teratogenic (warfarin embryopathy: nasal hypoplasia, stippled epiphyses) — avoid weeks 6–12; some allow in 2nd trimester for mechanical valves

— DOACs contraindicated — cross placenta, fetal effects unclear

— LMWH is the agent of choice — does not cross placenta; weight-based dosing, monitor anti-Xa (peak 0.6–1.0 IU/mL for therapeutic)

— Mechanical valves in pregnancy: complex — options include LMWH throughout, LMWH 1st trimester + warfarin 2nd/3rd, or warfarin throughout (highest maternal valve safety, fetal risk)

— Peripartum: stop LMWH 24 h before planned delivery; UFH bridge if very high risk; resume 4–6 h postpartum (12–24 h after neuraxial)

— Most often anticoagulated for catheter-associated thrombosis, congenital heart disease, Kawasaki

— LMWH or UFH; warfarin used for chronic indications

— Limited DOAC data; some approval for pediatric VTE (rivaroxaban, dabigatran in selected ages)

— Perioperative management mirrors adult principles but always involve pediatric hematology

— LMWH historically preferred for cancer-associated VTE; apixaban and edoxaban now equivalent for most (CARAVAGGIO, Hokusai-VTE Cancer)

— Avoid DOACs in luminal GI and GU cancers — higher bleed risk; use LMWH

— Perioperatively: extended postop VTE prophylaxis (4 weeks) after major abdominal/pelvic cancer surgery

— Warfarin remains standard — DOACs (especially rivaroxaban) shown inferior in triple-positive APS (TRAPS trial)

— Higher target INR (2.5–3.5) often used; bridge perioperatively given high thrombotic risk

Board pearl: A pregnant patient with a mechanical mitral valve is one of the highest-risk anticoagulation scenarios in medicine — management must be individualized with MFM, cardiology, and hematology; never choose a single answer without recognizing complexity.

Step 3 management: Cancer surgery patient — extend VTE prophylaxis to 28 days postop after major abdominopelvic cancer surgery, even after discharge.

Pregnancy:

Pediatrics:

Active cancer:

Antiphospholipid syndrome (APS):

Complications and Adverse Outcomes

— Major bleeding: Hgb drop ≥2 g/dL, transfusion ≥2 units, bleeding into critical site (intracranial, intraocular, intraspinal, pericardial, retroperitoneal, intramuscular with compartment syndrome)

— Surgical site hematoma: wound dehiscence, infection risk, reoperation

— GI bleed: especially with rivaroxaban, dabigatran; less with apixaban

— Intracranial hemorrhage: highest mortality; warfarin > DOACs

— Spinal/epidural hematoma: catastrophic complication of neuraxial in inadequately held anticoagulant

— Stroke in AF or mechanical valve patient

— Valve thrombosis — mechanical mitral > aortic; can be fatal

— Recurrent VTE, especially within 3 months of index event

— Mesenteric ischemia in high-risk patients

— Develops 5–10 days after heparin exposure (sooner with prior exposure)

— Platelet drop >50% from baseline; paradoxical thrombosis

— 4Ts score; confirmatory serotonin release assay

— Stop all heparin (including flushes), start argatroban or bivalirudin; do NOT give warfarin alone (skin necrosis risk)

— Occurs in protein C/S deficiency when warfarin given without heparin overlap

— Always overlap with heparin/LMWH until INR therapeutic ×2 days

— Restarting too early → bleeding; too late → thromboembolism

— Forgetting to restart at discharge — common transition-of-care failure

Key distinction: Major vs clinically relevant non-major (CRNM) bleeding — both matter but only major bleeding mandates reversal in most algorithms. CRNM (epistaxis, easy bruising) warrants reassessment, not reversal.

Board pearl: Postoperative epidural hematoma — back pain + new lower extremity weakness or sensory level + urinary retention = emergency MRI and neurosurgery consult; window to function-preserving decompression is <8 hours.

Bleeding complications:

Thromboembolic complications (off anticoagulation too long):

Heparin-induced thrombocytopenia (HIT):

Warfarin-induced skin necrosis:

Resumption errors:

Rebound hypercoagulability (controversial) — abrupt DOAC withdrawal occasionally cited

When to Escalate — ICU, Consult, and Inpatient Triage

— Major active hemorrhage requiring massive transfusion

— Intracranial hemorrhage of any volume

— Hemodynamic instability post-reversal

— Need for continuous heparin infusion with frequent aPTT monitoring postop in high-risk patient

— Pulmonary embolism postop with RV strain

— Antiphospholipid syndrome perioperative management

— HIT or suspected HIT

— Inherited thrombophilia with recurrent VTE

— DOAC reversal in major bleeding

— Pregnancy with mechanical valve

— Complex bridging in patient with mixed risk factors

— Mechanical valve patients (especially mitral)

— Recent stent <12 months needing non-cardiac surgery

— New AF discovered preoperatively

— LVAD patients

— Any neuraxial plan in anticoagulated patient

— Difficult airway + anticoagulation (bleeding risk during instrumentation)

— Need for invasive lines in anticoagulated patient

— LMWH bridging is outpatient — patient self-injects at home; education and clear written instructions critical

— UFH bridging requires admission — drip, aPTT monitoring

— Admit if: cannot self-administer, unreliable for follow-up, complex regimen, mechanical valve with severe LV dysfunction

— INR not at goal, recent thromboembolic event (<3 mo elective), uncontrolled HTN, active bleeding

Step 3 management: Patient on apixaban presents 4 h before scheduled hip replacement after taking morning dose — postpone surgery by 24–48 h; do not give andexanet "prophylactically" for an elective case.

CCS pearl: When ordering bridging in the ambulatory CCS environment, include: enoxaparin SC q12h, syringe demonstration, written calendar, follow-up phone call POD 1, INR check on resumption day. Skipping the patient-education orders loses points.

ICU triage criteria in anticoagulated patients:

Hematology consult triggers:

Cardiology consult triggers:

Anesthesiology preop consult triggers:

Inpatient vs outpatient bridging:

Cancellation/postponement criteria:

Key Differentials — Same-Category Decision Confusions

— CHA₂DS₂-VASc 4, no prior stroke → no bridge (BRIDGE trial population)

— CHA₂DS₂-VASc 4, prior stroke 2 years ago → consider bridge (prior stroke elevates true risk)

— CHA₂DS₂-VASc 6 with stroke 2 months ago → bridge (recent stroke = high)

— Bileaflet aortic, no AF, no stroke → low risk, no bridge

— Bileaflet aortic + AF → moderate, individualize

— Any mitral mechanical → high, bridge

— Older-generation (caged-ball, tilting disc) → high regardless of position

— Apixaban vs rivaroxaban for AF + GI bleed history → apixaban (lower GI bleed rate)

— Edoxaban vs apixaban in CrCl 30 → both acceptable; apixaban often chosen

— Dabigatran in elderly with renal decline → avoid; switch to apixaban

— Triple therapy (DOAC + DAPT) post-PCI in AF: limit to ≤1 month, then DOAC + single antiplatelet (AUGUSTUS trial)

— Continue aspirin perioperatively for secondary prevention in most non-cardiac surgery (POISE-2 nuance: aspirin not beneficial in primary prevention but continue for established CAD/stents)

— Holding apixaban "5 days like warfarin" → unnecessary thromboembolic exposure

— Holding warfarin "1 day like a DOAC" → supratherapeutic INR at surgery

— Bridging a DOAC → harmful, never indicated

Key distinction: Bridging is a warfarin-specific concept. DOACs have such short half-lives that simply holding them IS the bridge. Memorize this until automatic.

Board pearl: AUGUSTUS, PIONEER-AF, RE-DUAL PCI all converge: in AF + PCI, default to DOAC + clopidogrel (drop aspirin after the first 1–4 weeks). Triple therapy is the exception, not the rule.

"Should I bridge?" — distinguishing similar AF scenarios:

Mechanical valve nuances:

DOAC choice confusions:

Antiplatelet decisions overlapping with anticoagulation:

Hold timing pitfalls:

Key Differentials — Other-Category Considerations

— Anticoagulated patient with abnormal bleeding despite proper hold → consider von Willebrand disease, platelet dysfunction, undiagnosed factor deficiency

— Order vWF antigen/activity, platelet function assay, factor levels if pattern suggests

— Don't assume anemia is from the anticoagulant — work up: occult GI loss (colonoscopy), iron studies, B12/folate

— Patient on rivaroxaban with new microcytic anemia = GI malignancy workup, not just "drug effect"

— HIT (timing, 4Ts)

— ITP, drug-induced (vancomycin, linezolid, sulfas)

— DIC if sepsis/trauma

— TTP if MAHA + neurologic findings

— Liver disease, splenic sequestration

— Postop stroke — distinguish embolic (AF, valve, paradoxical) from watershed (hypotension) from hemorrhagic (anticoagulation)

— Postop DVT despite prophylaxis — consider HIT, malignancy, inadequate dosing in obesity

— Warfarin + antibiotics (TMP-SMX, metronidazole, fluconazole, ciprofloxacin) → INR spike

— DOACs + strong CYP3A4/P-gp inhibitors (ketoconazole, ritonavir, dronedarone) → increased levels

— DOACs + inducers (rifampin, phenytoin, carbamazepine, St. John's wort) → decreased levels and thrombosis risk

— Hemoptysis vs hematemesis; hematuria vs myoglobinuria; rectal bleeding vs vaginal/perineal source

Key distinction: A high INR is not the diagnosis — it's a finding. Always ask: new med, dietary change, hepatic decompensation, drug interaction, adherence error?

Board pearl: TMP-SMX given to a warfarin patient for a UTI is a classic question — INR rises within days. Either avoid TMP-SMX or empirically reduce warfarin and recheck INR in 3–5 days.

Distinguish anticoagulation issues from primary bleeding disorders:

Anemia preoperatively in anticoagulated patient:

Thrombocytopenia differentials in perioperative period:

Confusing thromboembolic events:

Drug interactions that mimic supratherapeutic anticoagulation:

Mimics of bleeding:

Secondary Prevention, Discharge Medications, and Long-Term Plan

— Specific drug, dose, frequency restart date documented

— First INR check date (for warfarin patients, 3–5 days post-resumption)

— Anticoagulation clinic referral or PCP follow-up arranged

— Patient teach-back on dosing, signs of bleeding, fall precautions

— Written instructions, MyChart message, or printed med list

— AF: lifelong if CHA₂DS₂-VASc ≥2 (men) or ≥3 (women); annual reassessment of risks

— Provoked VTE (surgery, trauma, immobilization): 3 months

— Unprovoked VTE: ≥3 months, consider indefinite based on D-dimer, bleed risk, patient preference

— Cancer-associated VTE: at least while cancer/treatment active

— Mechanical valve: lifelong; target INR by valve type/position

— Warfarin → DOAC: stop warfarin, start DOAC when INR <2 (or per drug-specific instructions)

— DOAC → warfarin: overlap until INR therapeutic ×2 days

— Parenteral → DOAC: start DOAC at time of next scheduled parenteral dose

— DAPT duration: DES typically 6–12 months, then ASA monotherapy; high-bleed-risk patients may shorten to 1–3 months (TWILIGHT, MASTER-DAPT)

— Never stop DAPT prematurely for elective procedures within minimum window

— Consistent vitamin K intake on warfarin (not avoidance — consistency)

— Avoid NSAIDs; use acetaminophen for analgesia

— Alcohol moderation; smoking cessation

— Fall prevention in elderly — PT, home safety eval

— Medic-alert bracelet

Step 3 management: Discharge order set must include specific resumption dates, bleeding precautions handout, and anticoagulation clinic appointment within 1 week — missing any of these is the most common transition-of-care failure mode.

Board pearl: LAA occlusion (Watchman) is an alternative for AF patients with contraindications to long-term anticoagulation — increasingly tested.

Resumption checklist at discharge:

Long-term anticoagulation strategy decisions:

Switching agents post-discharge:

Antiplatelet decisions post-stent:

Lifestyle counseling:

Follow-Up, Monitoring Parameters, and Counseling

— INR check 3–5 days after resumption postop

— Weekly until stable in therapeutic range

— Then every 2–4 weeks; stable patients up to 12 weeks

— Anticoagulation clinic involvement reduces bleeding and improves TTR (time in therapeutic range)

— No routine coag monitoring

— Annual CBC, BMP, LFTs at minimum; more often if renal/hepatic changes

— Medication reconciliation at every visit — check adherence, interactions

— Reassess indication and bleed risk annually

— Confirm patient took last LMWH dose at correct time

— Phone or message check-in POD 1–2

— INR check at resumption to ensure not subtherapeutic too long

— Soft toothbrush, electric razor, no contact sports

— Report black/tarry stools, blood in urine, unusual bruising, severe headache, falls with head impact

— Pressure × 10 min for minor cuts; ER for uncontrolled bleeding

— Inform all providers (dentist, surgeon, pharmacist) of anticoagulation

— Postop mobilization is itself thromboprophylaxis — early ambulation

— PT/OT with awareness of bleeding precautions and fall risk

— Cardiac rehab for patients post-valve or PCI continues with appropriate anticoagulation

— TTR ≥70% on warfarin

— DOAC adherence (pharmacy refill records)

— Annual reassessment documentation

CCS pearl: In the CCS environment, schedule the followup INR before the patient leaves the screen — clicking "discharge home" without ordering follow-up labs and clinic visit loses management points.

Board pearl: Patient on warfarin who travels or has poor lab access — consider switch to DOAC if no contraindication. Quality of anticoagulation matters as much as the choice of agent.

Warfarin follow-up cadence:

DOAC follow-up:

Bridging follow-up:

Bleeding precaution counseling (always document):

Rehab considerations:

Quality metrics tracked:

Ethical, Legal, and Patient Safety Considerations

— Discuss both bleeding and thromboembolic risks — patients often understand one but not the other

— Document the trade-off decision and patient's values

— For Jehovah's Witnesses or refusal-of-blood-products patients: pre-procedure transfusion alternatives plan, iron optimization, cell salvage discussion, EPO if anemia

— For patients lacking capacity: surrogate decision-maker; advance directives

— Medication reconciliation errors: anticoagulants are the #1 source of preventable harm at transitions

— "Held" anticoagulants forgotten and not restarted — track resumption in discharge instructions

— Mismatched outpatient instructions vs inpatient orders — verify pharmacy receives the correct discharge prescription

— Communicate to receiving provider (PCP, anticoagulation clinic) within 48–72 h

— Anticoagulation stewardship programs — pharmacy-led dosing, monitoring, education

— EHR alerts for drug interactions, renal dose adjustments, missed doses

— Read-back orders for high-alert medications (heparin, warfarin)

— Two-patient-identifier verification for anticoagulant administration

— Black-box reporting to FDA for adverse events

— Failure to restart anticoagulation at discharge → stroke/VTE

— Inappropriate bridging → bleeding harm

— Wrong-drug or wrong-dose errors (apixaban 5 mg vs 2.5 mg in elderly)

— Failure to recognize HIT and continued heparin → limb loss

— Falls resulting in injury — institutional incident report

— Medication errors regardless of harm — root-cause analysis

— Mandatory reporting if patient with intracranial hemorrhage from anticoagulation has impaired driving — state-specific

— DOACs are costly — verify insurance coverage; warfarin may be the only affordable option

— Health literacy: pictorial instructions, native-language materials for bridging regimens

Board pearl: The single most-tested patient safety item: anticoagulation reconciliation at discharge. If a stem describes a patient discharged after surgery with no clear anticoagulation restart plan, the answer is structured medication reconciliation and explicit resumption orders.

Informed consent specifics:

Transition-of-care risks (highest yield for Step 3):

Patient safety / system-level interventions:

Legal/malpractice exposure:

Reporting obligations:

Equity considerations:

High-Yield Associations and Rapid-Fire Clinical Facts

— Warfarin hold: 5 days; resume POD 1; INR goal <1.5

— DOAC hold: 24 h low / 48 h high bleed risk (normal renal function)

— LMWH last dose: 24 h preop, halve the dose

— UFH stop: 4–6 h preop

— Clopidogrel hold: 5 d; ticagrelor 3–5 d; prasugrel 7 d; aspirin often continued

— Platelets ≥50K for surgery, ≥80–100K for neuraxial

— Neuraxial: DOAC 72 h, therapeutic LMWH 24 h, prophylactic LMWH 12 h

— BRIDGE — no bridging for most AF on warfarin

— PERIOP-2 — bridging in mechanical valves

— BRUISE-CONTROL — continue warfarin for device implant

— PAUSE — standardized DOAC hold protocol (1–2 days, no measurement, no bridging)

— AUGUSTUS — apixaban + P2Y12, drop aspirin early in AF post-PCI

— POISE-2 — perioperative aspirin in non-cardiac surgery

— CARP — no preop revascularization purely for non-cardiac surgery

— Warfarin → Vitamin K + 4F-PCC

— Dabigatran → Idarucizumab

— Apixaban/rivaroxaban → Andexanet alfa (or 4F-PCC)

— Heparin → Protamine

— LMWH → Protamine (partial)

— Antiplatelets → Platelets + DDAVP

— Cataract, dental, derm → don't stop

— Pacemaker → continue warfarin (not bridge)

— Colonoscopy + polypectomy → hold DOAC

— Neuraxial → strict hold per ASRA

— Warfarin ↑ INR: amiodarone, TMP-SMX, metronidazole, fluconazole, ciprofloxacin

— DOAC ↑: CYP3A4/P-gp inhibitors (ketoconazole, ritonavir, dronedarone)

— DOAC ↓: rifampin, phenytoin, carbamazepine, St. John's wort

Board pearl: PAUSE trial is the cleanest DOAC perioperative protocol — hold 1 day before low-bleed, 2 days before high-bleed surgery; no measurement, no bridging — bleeding rates very low (<2%).

Numbers to memorize cold:

Trial-name recall:

Reversal pairings (must memorize):

Procedure-specific shortcuts:

High-yield interactions:

Board Question Stem Patterns

— 70-year-old AF on warfarin (CHA₂DS₂-VASc 4), no prior stroke, elective hernia repair → Hold warfarin 5 days, no bridge, INR day before, resume POD 1. Tempting wrong answer: bridge with LMWH.

— Mechanical mitral valve patient for cholecystectomy → Hold warfarin, bridge with therapeutic LMWH. Mitral position = high risk.

— Apixaban for AF, elective colonoscopy with possible polypectomy → Hold 48 h preop, resume 24–48 h postop, no bridging.

— Patient on dabigatran with hip fracture needing OR in 12 h → Idarucizumab 5 g IV, proceed.

— INR 1.7 day before surgery → Vitamin K 1–2.5 mg PO, recheck morning of surgery.

— DES placed 4 months ago, elective surgery → Defer elective surgery to 6–12 months; if urgent, continue DAPT or at minimum aspirin, cardiology consult.

— Postop epidural patient on LMWH with new leg weakness/back pain → STAT MRI spine, neurosurgery consult, hold anticoagulation, reverse if necessary.

— Day 7 post-cardiac surgery, platelets dropped from 250 to 80, new DVT → Stop all heparin, start argatroban, send HIT antibody and SRA.

— Warfarin patient given TMP-SMX for UTI, returns with INR 8 and gingival bleeding → Hold warfarin, vitamin K 2.5 mg PO (no major bleed) or 10 mg IV + 4F-PCC if major bleed.

— Pregnant patient with mechanical mitral valve → MFM/cardiology/hematology; LMWH or warfarin per trimester with anti-Xa monitoring.

Board pearl: When the stem emphasizes "AF on warfarin, elective procedure," your default 2024+ answer is no bridge. When it emphasizes "mechanical mitral" or "recent VTE/stroke," bridge. This binary captures the majority of stems.

Step 3 management: Pick the answer that includes both the hold AND the resumption plan — questions reward complete management thinking.

Pattern 1 — "No bridge" AF trap:

Pattern 2 — Mechanical mitral valve:

Pattern 3 — DOAC perioperative:

Pattern 4 — Emergency surgery on DOAC:

Pattern 5 — INR slightly elevated day before surgery:

Pattern 6 — Stent + non-cardiac surgery:

Pattern 7 — Spinal hematoma red flag:

Pattern 8 — HIT:

Pattern 9 — Drug interaction:

Pattern 10 — Pregnancy and valve:

One-Line Recap

Perioperative anticoagulation management is the disciplined trade-off between thromboembolic risk and procedural bleeding risk — driven by indication, agent half-life, renal function, and procedure bleed tier — where most warfarin patients with AF should NOT be bridged, DOACs should NEVER be bridged, and the highest-yield errors are at transitions of care.

Board pearl: If you remember only three things — (1) BRIDGE trial says don't bridge most AF, (2) PAUSE trial says short hold and no monitoring for DOACs, (3) anticoagulation reconciliation at discharge is the single highest-yield safety item — you will answer the majority of Step 3 questions on this topic correctly.

Step 3 management: Every perioperative anticoagulation note should explicitly state: indication, agent/dose, last dose date-time, CrCl, thromboembolic risk tier, procedural bleed risk tier, hold plan, bridging decision with rationale, resumption plan with date, and follow-up labs — this template prevents nearly all preventable harm and earns full credit on board vignettes and CCS cases alike.

Hold cheat-sheet: Warfarin 5 d; DOAC 24 h low / 48 h high bleed (longer with renal impairment); LMWH last dose 24 h preop; clopidogrel 5 d; aspirin usually continue.

Bridge cheat-sheet: Bridge only mechanical mitral, recent stroke/VTE (<3 mo), or severe thrombophilia. Don't bridge ordinary AF (BRIDGE trial). Never bridge DOACs.

Reversal cheat-sheet: Warfarin → vit K + 4F-PCC; dabigatran → idarucizumab; Xa-DOAC → andexanet or 4F-PCC; heparin → protamine.

Transition-of-care cheat-sheet: Write specific resumption dates and doses, schedule INR check 3–5 days post-resumption, refer to anticoagulation clinic, give bleeding precaution handout, communicate to PCP within 48–72 h.