Cardiovascular

DOAC reversal agents: andexanet and idarucizumab

Clinical Overview and When to Suspect Life-Threatening DOAC Bleeding

— Direct thrombin inhibitor: dabigatran (Pradaxa)

— Factor Xa inhibitors: apixaban (Eliquis), rivaroxaban (Xarelto), edoxaban (Savaysa), betrixaban

— Idarucizumab (Praxbind): humanized monoclonal antibody fragment binding dabigatran with ~350× the affinity of thrombin

— Andexanet alfa (Andexxa): recombinant modified inactive factor Xa "decoy" that sequesters apixaban, rivaroxaban (FDA-approved) and binds edoxaban/enoxaparin off-label

— Patient on a DOAC with life-threatening or uncontrolled bleeding (intracranial hemorrhage, retroperitoneal, GI with shock, pericardial, intraocular, airway)

— Need for emergent surgery or invasive procedure that cannot wait for drug clearance (typically <8 h since last dose for high-bleed-risk surgery)

— Suspected DOAC overdose with bleeding diathesis

— Normal renal function: most DOACs are functionally absent by 24–48 h after last dose; reversal generally not indicated beyond ~3–5 half-lives unless renal failure.

Direct oral anticoagulants (DOACs) in widespread US use:

Reversal agents emerged because DOACs lack the routine INR monitoring of warfarin yet still cause major bleeding in ~2–3%/year of treated patients.

When to suspect a DOAC-related emergency requiring reversal:

Key timing: last-dose history is the single most important data point.

Step 3 management: for any anticoagulated patient with new neurologic deficit, the ED clock starts simultaneously for (1) non-contrast head CT, (2) DOAC last-dose and agent identification, (3) typing/crossmatch, and (4) calling pharmacy to mobilize reversal agent — these are parallel, not sequential, orders.

Board pearl: the question stem giveaway is "last took her apixaban 2 hours ago" or "took dabigatran this morning" coupled with ICH on CT — that temporal proximity is what makes reversal indicated rather than supportive care alone.

Presentation Patterns and Key History

— Elderly AFib patient on apixaban after a ground-level fall with new headache, vomiting, or focal deficit → suspect traumatic ICH

— Patient on rivaroxaban for VTE presenting with hematemesis, melena, or hemodynamic instability

— Dabigatran-treated patient requiring emergent neurosurgery, ex-lap, or hip fracture repair within hours

— Postpartum or post-procedure retroperitoneal hematoma with flank pain, falling Hgb, and femoral neuropathy

— Exact agent and dose (apixaban 5 mg BID vs 2.5 mg BID changes risk/dose calculus)

— Time of last dose — drives whether reversal is even meaningful

— Indication for anticoagulation (AFib vs mechanical valve vs recent VTE) — affects thrombotic risk after reversal

— Renal function trend — CKD prolongs DOAC half-life, especially dabigatran (80% renal)

— Concomitant antiplatelets (aspirin, clopidogrel, DAPT post-PCI) which markedly worsen bleeding

— Drug interactions: strong CYP3A4/P-gp inhibitors (azoles, ritonavir, amiodarone, verapamil) elevate DOAC levels

— GCS drop, anisocoria, or Cushing response

— Massive transfusion criteria triggered (≥4 units PRBC in 1 h, or ≥10 in 24 h)

— Hemodynamic instability despite 2 L crystalloid and 2 units PRBC

Classic high-yield presentations that trigger DOAC reversal consideration:

Essential history to obtain immediately (often from family, EMS, or pharmacy if patient obtunded):

Red flags suggesting reversal rather than observation:

CCS pearl: in a CCS case, ordering "medication reconciliation" and "contact pharmacy" early surfaces the DOAC and last-dose timing — these orders advance the clock productively rather than wasting simulated minutes.

Key distinction: a patient on a DOAC who took the last dose >48 h ago with normal renal function rarely benefits from reversal; treat as a non-anticoagulated bleed with PRBCs, source control, and supportive care.

Physical Exam Findings and Hemodynamic Assessment

— Airway: GCS ≤8, expanding neck hematoma, or oropharyngeal bleeding mandates early intubation before reversal even arrives

— Breathing: hemothorax, pulmonary hemorrhage — auscultate, get upright CXR or eFAST

— Circulation: HR, BP, narrow pulse pressure, capillary refill, mental status; class III shock = ~30–40% blood loss

— ICH: pupillary asymmetry, lateralizing weakness, posturing, Cushing triad (HTN, bradycardia, irregular respirations)

— GI: rectal exam for melena/hematochezia, NG aspiration if upper source suspected, abdominal tenderness

— Retroperitoneal: Grey Turner / Cullen signs are late; earlier clues are unilateral flank pain + femoral nerve palsy (psoas hematoma) + tachycardia disproportionate to visible blood loss

— Intramuscular/compartment: tense compartment, pain with passive stretch, paresthesias — measure pressures

— MAP ≥65 mmHg (≥80–100 in acute ICH per guideline-suggested SBP <140 in some scenarios, individualize)

— Permissive hypotension (SBP 80–90) in penetrating trauma until source controlled — but not in TBI/ICH

— Avoid over-resuscitation with crystalloid; favor balanced blood products

Primary survey priorities in suspected DOAC-related hemorrhage:

Targeted exam findings by bleeding site:

Hemodynamic targets while preparing reversal:

Board pearl: a patient on dabigatran with acute kidney injury (e.g., NSAID-precipitated) has effectively a "stored dose" — exam may show progressive oozing from IV sites and gums, an under-recognized sign of supratherapeutic drug levels.

Step 3 management: simultaneous orders — 2 large-bore IVs, type & crossmatch 4 units, activate massive transfusion protocol if indicated, and do not wait for labs to confirm DOAC level before mobilizing reversal in clear life-threatening bleed; the clinical scenario alone justifies it.

Diagnostic Workup — Initial Labs, Imaging, ECG

— CBC with platelets, CMP (focus on creatinine for renal clearance), coagulation panel (PT/INR, aPTT), fibrinogen, type & crossmatch

— Lactate and VBG for perfusion

— Troponin and ECG if hemodynamic instability or chest pain

— Dabigatran: prolongs aPTT and thrombin time (TT); a normal TT essentially excludes clinically relevant dabigatran levels. Dilute TT (Hemoclot) quantifies.

— Factor Xa inhibitors (apixaban, rivaroxaban): standard PT/INR and aPTT are insensitive and unreliable — a normal PT does not rule out drug effect. Anti-Xa level calibrated to the specific drug is the gold standard.

— Edoxaban modestly prolongs PT.

— Suspected ICH → non-contrast head CT immediately; CTA if vascular lesion suspected

— GI bleed → upright CXR, then EGD/colonoscopy or CTA if brisk

— Trauma → FAST, CT chest/abdomen/pelvis with contrast

— Retroperitoneal → CT abdomen/pelvis with contrast; spot the active extravasation ("blush")

— Baseline rhythm matters: AFib patients reversed for bleeding are at high re-thrombotic risk, especially after andexanet

— Look for ischemic changes that might be precipitated by anemia

Stat labs in any DOAC-related bleed:

Coagulation test interpretation — high yield:

Do NOT delay reversal awaiting drug-specific assays in life-threatening bleeding — use clinical scenario + last-dose timing.

Imaging algorithm:

ECG considerations:

Board pearl: a normal thrombin time in a patient on dabigatran is your "off-ramp" — it tells you there is no meaningful drug on board and idarucizumab is not indicated.

Key distinction: PT/INR is the right test for warfarin reversal decisions, not DOACs. A board stem giving you "INR 1.1" in a rivaroxaban patient is a trap — the drug can still be fully active.

Diagnostic Workup — Advanced and Confirmatory Studies

— Dilute thrombin time (Hemoclot) or ecarin clotting time → quantifies dabigatran

— Chromogenic anti-Xa assay calibrated to apixaban, rivaroxaban, or edoxaban → quantifies factor Xa inhibitors

— Drug level <30 ng/mL is generally below the threshold at which reversal adds value

— Useful adjunct in trauma and massive transfusion to guide product administration (FFP, cryo, platelets)

— Limited sensitivity for DOACs themselves; cannot replace anti-Xa for drug quantification

— Head CT at 6 h post-reversal (or sooner with neuro change) for ICH — guides decision for repeat dosing or neurosurgery

— Serial Hgb every 2–4 h initially

— CTA chest/abdomen/pelvis for unexplained shock + DOAC use

— MRI brain when CT is negative but neuro deficit persists (rare, ischemic mimic)

— Used if specific reversal agent is unavailable or contraindicated, or as off-label adjunct for Xa inhibitor bleeding (typical dose 50 units/kg 4F-PCC)

— Not technically "reversal" but pragmatic and guideline-supported by ACC, neurocritical care society

Drug-specific quantitative assays (used when available, mostly academic centers):

Viscoelastic testing (TEG/ROTEM):

Repeat imaging to detect hematoma expansion:

Cross-sectional confirmation in suspected occult bleeds:

Pre-reversal type & screen + crossmatch for ≥4 units PRBC; ensure ready FFP, platelets, cryoprecipitate

Activated PCC (aPCC, FEIBA) and 4-factor PCC considerations:

Step 3 management: in an institution without andexanet on formulary, 4F-PCC 50 U/kg is the accepted alternative for life-threatening Xa-inhibitor bleeding — know this because many hospitals have not adopted andexanet due to cost (~$25,000–$50,000/dose).

Board pearl: activated charcoal within 2 hours of DOAC ingestion (especially in overdose) can meaningfully reduce systemic absorption — an easy adjunct people forget.

Risk Stratification and First-Line Management Logic

— Yes, if: (1) life-threatening bleed OR emergent surgery <8 h, AND (2) DOAC taken within ~3–5 half-lives (typically <24 h, longer with renal failure), AND (3) clinical suspicion of meaningful drug effect

— No, if: minor bleeding controllable with local measures, elective surgery (just hold the DOAC), or drug-level/TT confirms negligible activity

— Major bleed: fatal, critical site (intracranial, intraspinal, intraocular, retroperitoneal, pericardial, intramuscular with compartment syndrome), Hgb drop ≥2 g/dL, or ≥2 units PRBC

— Clinically relevant non-major: requires medical intervention but not major-criteria

— Minor: bruising, epistaxis controlled by pressure

— Reversal of anticoagulation temporarily restores hypercoagulability; andexanet carries a ~10% thrombotic event rate in trials (ANNEXA-4)

— Counsel: stroke, MI, DVT/PE, device thrombosis all increased

— Plan to resume anticoagulation as soon as hemostatically safe, often within 1–2 weeks post-ICH (per AHA/ASA guidance, individualize)

— Source control (endoscopy, IR embolization, surgery)

— Blood product resuscitation: PRBC, platelets if <50k (or <100k for ICH), FFP for dilutional coagulopathy, cryo if fibrinogen <150

— Hold all anticoagulants and antiplatelets

— BP control in ICH (SBP target individualized, often <140–160)

— Reverse any aspirin/clopidogrel with platelet transfusion only if neurosurgery planned (PATCH trial cautions against in spontaneous ICH)

Decision algorithm — should this patient get a reversal agent?

Bleeding severity classification (ISTH):

Thrombotic risk re-stratification before reversal:

Universal adjuncts regardless of reversal agent:

Step 3 management: the decision to reverse is clinical, not laboratory — do not wait on anti-Xa levels in a deteriorating ICH patient.

Key distinction: "holding the DOAC" is appropriate management for minor bleeds or elective procedures; active reversal is reserved for life/limb/vision-threatening situations.

Pharmacotherapy — Idarucizumab and Andexanet Dosing

— Dose: 5 g IV total, given as two 2.5 g IV boluses ≤15 min apart (each over 5–10 min)

— Onset: immediate (within minutes); normalization of dilute TT/ecarin clotting within an hour

— Duration: ~24 h; repeat 5 g dose if recurrent clinically relevant bleeding with elevated coagulation markers

— No dose adjustment for renal or hepatic impairment

— Adverse effects: hypersensitivity, hereditary fructose intolerance (contains sorbitol), thromboembolism if anticoagulation not resumed

— REVERSE-AD trial: hemostasis achieved in ~70% within 24 h

— Low-dose regimen: 400 mg bolus at 30 mg/min, then 4 mg/min × up to 120 min (480 mg total)

· Indicated when: apixaban ≤5 mg OR rivaroxaban ≤10 mg last dose AND >8 h since dose (or unknown)

— High-dose regimen: 800 mg bolus at 30 mg/min, then 8 mg/min × up to 120 min (960 mg total)

· Indicated when: apixaban >5 mg, rivaroxaban >10 mg, or unknown dose and last dose <8 h ago

— Onset: rapid reduction of anti-Xa activity within minutes; rebound after infusion ends (~2 h)

— ANNEXA-4 trial: ~80% achieved excellent/good hemostasis; ~10% had thrombotic events within 30 days

— Causes heparin resistance for ~24 h — important if patient needs cardiac surgery or heparinized CRRT/ECMO; use bivalirudin instead

— Very expensive; many centers use 4F-PCC 50 U/kg as alternative (ANNEXA-I trial showed andexanet superior for hemostasis but with more thrombotic events vs usual care)

Idarucizumab (Praxbind) — for dabigatran:

Andexanet alfa (Andexxa) — for apixaban and rivaroxaban (FDA-approved); edoxaban off-label:

Andexanet caveats:

Board pearl: the bolus + 2-hour infusion structure of andexanet is the most testable mechanical detail — and the heparin-resistance interaction is a classic surgical scenario distractor.

Step 3 management: order both bolus and infusion components simultaneously from pharmacy; don't let the bolus run without the infusion already on the way.

Procedural and Adjunctive Management

— GI bleed: EGD/colonoscopy within 24 h (sooner if unstable); IR embolization for refractory; surgery as last resort

— ICH: neurosurgical consultation for hematoma volume >30 mL, midline shift, IVH/hydrocephalus (EVD), posterior fossa bleeds >3 cm

— Retroperitoneal/intra-abdominal: IR-guided embolization is first-line for active extravasation; surgical exploration for hemodynamic failure

— Traumatic solid organ injury: REBOA, angioembolization, or laparotomy per ATLS

— 1:1:1 ratio of PRBC : FFP : platelets

— TXA 1 g IV bolus + 1 g over 8 h if within 3 h of traumatic bleeding (CRASH-2); also reasonable in many non-trauma scenarios

— Cryoprecipitate if fibrinogen <150 mg/dL

— Calcium replacement (citrate toxicity from massive blood products → ionized hypocalcemia)

— Dabigatran is ~60% dialyzable (low protein binding, low molecular weight)

— Useful adjunct in renal failure with persistent bleeding despite idarucizumab, or when reversal unavailable

— Apixaban, rivaroxaban are highly protein-bound → not dialyzable

Source control is non-negotiable — reversal agents are bridges, not solutions.

Massive transfusion protocol (MTP):

Hemodialysis for dabigatran:

Activated charcoal: within 2 h of ingestion for overdose scenarios

Local hemostatic measures: topical TXA, packing, gelfoam, electrocautery, balloon tamponade (esophageal varices)

CCS pearl: when running a DOAC-ICH CCS case, sequence is — ABCs, neuro exam, head CT, type & cross, reversal agent, BP control, neurosurgery consult, ICU admission. Missing the consult is a common deduction even when the medicine is correct.

Key distinction: dabigatran is dialyzable; Xa inhibitors are not — a high-yield differentiator when reversal agents are unavailable.

Special Populations — Elderly and Renal/Hepatic Impairment

— Vast majority of DOAC bleeds occur in patients >75 with AFib

— Polypharmacy increases bleeding risk: SSRIs, NSAIDs, antiplatelets, steroids

— Falls risk is not an absolute contraindication to anticoagulation — meta-analyses show net benefit favors continued therapy in most CHA₂DS₂-VASc ≥2 patients despite fall history

— Underdosing apixaban in elderly is a common error: 2.5 mg BID requires 2 of 3 criteria (age ≥80, weight ≤60 kg, Cr ≥1.5)

— Dabigatran: 80% renal; contraindicated if CrCl <30 (US) or <15 (some labels); accumulation drives bleeding risk

— Rivaroxaban: ~35% renal; avoid if CrCl <15

— Apixaban: ~27% renal; can be used down to dialysis with caution (preferred DOAC in advanced CKD per some registries)

— Edoxaban: ~50% renal; paradoxically less effective in CrCl >95 (avoid in normal-renal AFib)

— Dabigatran levels can be 5–10× expected — strongly consider hemodialysis + idarucizumab

— Idarucizumab dosing is unchanged in renal failure

— Andexanet dosing also unchanged in renal failure

— All DOACs partially hepatically metabolized (apixaban, rivaroxaban most so via CYP3A4)

— Child-Pugh C: avoid all DOACs

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

Elderly considerations:

Renal impairment — drug-specific:

In AKI/CKD with bleeding:

Hepatic impairment:

Step 3 management: in an 82-year-old on dabigatran with new AKI and GI bleeding — order idarucizumab and nephrology for emergent HD. The combination is the highest-yield maneuver.

Board pearl: apixaban is the most renal-friendly DOAC and the most common right-answer DOAC in CKD AFib stems.

Special Populations — Pregnancy, Pediatrics, and Other Subgroups

— DOACs are not recommended in pregnancy (limited human data, animal teratogenicity signals); LMWH is the anticoagulant of choice in pregnant patients requiring anticoagulation

— If a pregnant patient on a DOAC presents with bleeding, reversal agents (idarucizumab, andexanet) have no pregnancy safety data — use is case-by-case in life-threatening bleeds; the benefit clearly outweighs unknown fetal risk

— Post-reversal, transition to LMWH for ongoing anticoagulation needs

— Lactation: idarucizumab and andexanet are large proteins, unlikely to transfer; brief interruption of breastfeeding is reasonable

— DOACs increasingly used in pediatric VTE (dabigatran, rivaroxaban approved in some pediatric VTE indications)

— Reversal agent dosing in children is not well established; consult pediatric hematology

— Idarucizumab has been used off-label in pediatric dabigatran emergencies

— DOACs are contraindicated (RE-ALIGN trial: dabigatran inferior to warfarin); these patients should be on warfarin

— A board stem with "mechanical mitral valve on dabigatran" is testing recognition that the prescription itself was inappropriate

— DOACs inferior to warfarin (TRAPS trial); avoid

— Older guidance avoided DOACs; updated ISTH 2021 supports apixaban and rivaroxaban for VTE/AFib in obese patients; dabigatran/edoxaban still less data

Pregnancy and lactation:

Pediatrics:

Mechanical heart valves:

Antiphospholipid syndrome (APS), especially triple-positive:

Obesity (BMI >40 or weight >120 kg):

Bariatric surgery (post-op): absorption altered — switch to warfarin or LMWH

Board pearl: mechanical valve + DOAC = wrong drug, and the answer is to switch to warfarin, not to add a reversal agent.

Key distinction: in pregnancy, the question almost always tests LMWH selection over DOAC, not reversal logistics.

Complications and Adverse Outcomes

— Andexanet alfa: ~10% thromboembolic event rate at 30 days (ischemic stroke, MI, DVT/PE, device thrombosis) in ANNEXA-4

— Idarucizumab: ~5% thrombotic events at 30 days in REVERSE-AD

— Mechanism: rapid removal of anticoagulant effect in patients with underlying prothrombotic states (AFib, recent VTE, malignancy)

— Mitigation: resume anticoagulation as soon as hemostatically safe

— Binds heparin-antithrombin complex

— Lasts up to ~24 h

— Cardiac surgery, CRRT, ECMO within this window → use bivalirudin (direct thrombin inhibitor, doesn't require AT) instead of heparin

— Anti-Xa activity rebounds ~2 h after infusion ends

— Clinically: may need re-monitoring or repeat dosing; rebound is one driver of recurrent bleeding

— Rare anaphylaxis

— Sorbitol content → contraindicated in hereditary fructose intolerance

— Reappearance of unbound dabigatran 12–24 h later from peripheral redistribution; repeat 5 g dose may be needed

— Andexanet ~$25,000–$50,000/dose

— Idarucizumab ~$3,500/dose

— Many community hospitals lack andexanet — know 4F-PCC alternative

— ~20–30% of patients in trials did not achieve excellent/good hemostasis — reversal is not 100% effective; source control remains paramount

Thrombotic complications of reversal:

Heparin resistance with andexanet:

Rebound anticoagulation after andexanet:

Idarucizumab-specific:

Hypersensitivity and infusion reactions for both agents — pre-medication generally not required

Cost and access:

Failure of hemostasis:

Step 3 management: after reversal, daily clinical reassessment for thrombotic events: leg swelling, chest pain/dyspnea, new neuro deficit, line thrombosis — and have a planned date to restart anticoagulation (typically 1–2 weeks for ICH, 3–7 days for GI bleed after source control).

Board pearl: the post-andexanet patient needing CABG = bivalirudin, not heparin.

When to Escalate Care — ICU, Consult, and Inpatient Triage

— Any intracranial hemorrhage regardless of size

— Hemodynamic instability requiring vasopressors or massive transfusion

— Airway compromise (neck hematoma, oropharyngeal bleed, GCS ≤8)

— Post-reversal monitoring for rebound (especially andexanet) and thrombotic events

— Active source control underway (post-embolization, post-op)

— Neurosurgery for any ICH — even if non-operative, for ICP monitoring, EVD, serial exams

— GI for upper or lower GI bleeds — endoscopy within 24 h (within 12 h if unstable variceal)

— Interventional radiology for retroperitoneal, visceral, or pelvic bleeds with extravasation

— Cardiology if AFib management and anticoagulation reinitiation strategy needed

— Hematology for complex coagulopathy or atypical DOACs

— Nephrology for hemodialysis in dabigatran toxicity with renal failure

— Pharmacy for dose verification, formulary alternatives, cost authorization

— Community ED without andexanet or neurosurgery → transfer to tertiary center after initiating 4F-PCC and stabilizing airway

— Don't delay transfer for non-essential workup

— Step-down may be appropriate for GI bleeds post-endoscopy with stable Hgb and reversed coagulopathy

— ICH always ICU initially

ICU admission criteria for DOAC-related bleeding:

Consultant orchestration:

Transfer considerations:

Floor vs ICU vs step-down:

CCS pearl: in CCS, ordering "ICU admission" early for ICH and simultaneously placing neurosurgery and pharmacy consults reflects parallel processing — the simulator credits this orchestration.

Step 3 management: post-stabilization, ensure DVT prophylaxis decisions are revisited daily — mechanical (SCDs) is safe; pharmacologic prophylaxis usually restarted 24–48 h after hemostasis confirmed, individualized.

Key distinction: transfer vs treat-in-place hinges on availability of definitive intervention (neurosurgery, IR, GI), not just reversal agent stocking.

Key Differentials — Same-Category (Anticoagulant-Related) Causes

— INR elevated; mechanism is vitamin K-dependent factor deficiency

— Reversal: 4F-PCC (Kcentra) 25–50 U/kg based on INR + IV vitamin K 10 mg (not just PO)

— FFP only if PCC unavailable (slower, volume-heavy)

— Distinguishing from DOAC bleed: drug history, INR markedly elevated

— Protamine sulfate reverses unfractionated heparin completely; partially reverses LMWH (~60–80% for enoxaparin)

— Dose: 1 mg protamine per 100 units heparin in last 2–3 h

— Watch for protamine-induced hypotension, anaphylaxis (especially in fish allergy, prior vasectomy, NPH insulin users)

— No specific antidote; not reversed by protamine

— Off-label: rFVIIa (NovoSeven) or aPCC

— Stop infusion; cryoprecipitate 10 units to replete fibrinogen; consider TXA

— Platelets and FFP as adjuncts

— Platelet transfusion only if neurosurgery planned (PATCH trial cautions against in spontaneous ICH)

— Desmopressin (DDAVP) 0.3 mcg/kg may help with aspirin/uremic platelet dysfunction

— Patient on DOAC + clopidogrel + SSRI after PCI — common real-world setup

— Address each component; reverse DOAC + platelets if procedurally needed

Warfarin-related major bleed:

Heparin/LMWH-related bleed:

Fondaparinux-related bleed:

Thrombolytic-related bleed (tPA, TNK):

DAPT-related bleed (aspirin + P2Y12):

Multiple-agent ("anticoag soup") bleeds:

Board pearl: warfarin reversal = 4F-PCC + IV vitamin K, dabigatran = idarucizumab, apixaban/rivaroxaban = andexanet or 4F-PCC, heparin = protamine, fondaparinux = no antidote (rFVIIa off-label).

Key distinction: vitamin K reverses warfarin (durable, slow), idarucizumab reverses dabigatran (immediate, drug-specific) — vitamin K does nothing for DOACs.

Key Differentials — Other-Category Causes of Bleeding

— Hemophilia A/B: prolonged aPTT, normal PT; treat with factor VIII or IX concentrate; DDAVP for mild hemophilia A

— vWD: prolonged bleeding time/PFA-100, variable aPTT; treat with DDAVP or vWF concentrate

— Distinguish from DOAC by family history, prior bleeding episodes, lifelong pattern

— Liver disease: elevated PT/INR, low fibrinogen, thrombocytopenia; treat with vitamin K, FFP for procedures, platelets, cryo

— DIC: prolonged PT/aPTT, low fibrinogen, elevated D-dimer, schistocytes, low platelets; treat underlying cause + supportive products

— Vitamin K deficiency (malnutrition, antibiotics, malabsorption, neonates): elevated PT/INR

— Uremic platelet dysfunction: treat with DDAVP, dialysis, cryoprecipitate

— ITP, TTP, HIT, drug-induced (heparin, vancomycin, linezolid)

— Platelet transfusion for ITP only with severe bleeding; avoid platelets in TTP and HIT (paradoxical thrombosis)

— Hypothermia, acidosis, hemodilution — "lethal triad"

— Treat with balanced resuscitation, TXA, warming

— Diverticulosis, AVMs, peptic ulcer, Mallory-Weiss, varices, aneurysm rupture

— Patient may coincidentally be on a DOAC — don't anchor on the drug; pursue source

Inherited coagulopathies presenting acutely:

Acquired coagulopathies:

Thrombocytopenia-related bleeding:

Trauma-induced coagulopathy:

Anatomic/structural bleeds without coagulopathy:

Board pearl: an AFib patient on apixaban with melena and a 5-cm AAA on imaging — the differential includes aortoenteric fistula, not just DOAC effect; reverse anticoagulation and call vascular surgery.

Step 3 management: in any anticoagulated bleeder, ask "what would I work up if they weren't anticoagulated?" — pursue that workup in parallel.

Secondary Prevention and Long-Term Plan

— Intracranial hemorrhage: generally resume at 1–2 weeks if indication remains (AFib stroke risk, mechanical valve); MR-CLEAN registry and observational data favor 4–8 weeks for larger ICH; individualize with neurology

— GI bleed (non-variceal): restart 3–7 days after definitive endoscopic hemostasis

— Variceal bleed: after band ligation + propranolol/carvedilol initiation, typically 1–2 weeks

— Surgery: prophylactic dose at 24 h, therapeutic at 48–72 h depending on bleeding risk

— Generally resume the same DOAC if bleed wasn't drug-class-specific

— Switch to apixaban (lowest bleed risk in trial data) if GI bleed on rivaroxaban or dabigatran

— Switch to warfarin for mechanical valves or APS

— Consider LAA occlusion (Watchman) in AFib patients with recurrent bleeds or absolute contraindication to long-term anticoagulation

— Stop concurrent NSAIDs, aspirin (if not needed for ACS/recent PCI)

— Treat H. pylori

— Add PPI for upper GI bleed history

— Control BP (<130/80 in most)

— Discontinue SSRIs if alternative available

— Alcohol counseling, fall-prevention assessment

— Recognize signs of bleeding (melena, hematuria, severe headache)

— Bring DOAC bottle/list to all ED visits

— Inform all providers (especially dentists, surgeons) of anticoagulation

— Carry medical alert ID

Restarting anticoagulation after reversal — high-yield timing:

Choice of resumed agent:

Address modifiable bleeding risk factors:

Patient education at discharge:

Step 3 management: at discharge after DOAC-related ICH, the shared decision-making conversation about resuming anticoagulation must be documented — net stroke vs rebleed risk discussion, often with neurology and cardiology input.

Board pearl: apixaban has the lowest GI bleeding risk among DOACs — favored after a GI bleed.

Follow-Up, Monitoring, and Counseling

— Serial vital signs and neuro exams q1h initially in ICU

— Hgb q4–6h for first 24 h, then daily

— Coagulation markers (aPTT/TT for dabigatran; anti-Xa if available for Xa inhibitors) at baseline, 4–12 h, and 24 h

— Renal function daily

— Surveillance for thrombotic complications: lower extremity Doppler if indicated, ECG for atrial arrhythmias, troponin if chest pain

— Definitive source control achieved (endoscopy report, surgical pathology, imaging)

— Hemodynamically stable for ≥24 h off transfusion

— Clear written plan for anticoagulation resumption with date and dose

— Outpatient follow-up scheduled

— PCP within 1–2 weeks of discharge for medication reconciliation

— Cardiology or hematology in 2–4 weeks for anticoagulation strategy

— GI within 4–8 weeks post-GI bleed for surveillance endoscopy or polyp follow-up

— Neurology in 4–6 weeks post-ICH for re-imaging and resumption decision

— Adherence: missed doses raise stroke risk; doubling up raises bleed risk — patient-specific instructions

— Drug-drug interactions: review with every new prescription (especially azoles, rifampin, phenytoin, amiodarone)

— Renal function checks: CMP every 6–12 months, more often if CKD or change in clinical status

— Procedural planning: tell every provider; hold DOAC 24–48 h before low-risk and 48–72 h before high-risk procedures (longer with renal impairment)

— BP, cholesterol, weight, smoking cessation, alcohol moderation

— Fall prevention: home safety, vision check, deprescribing sedating medications

Inpatient monitoring post-reversal:

Discharge planning checkpoints:

Follow-up cadence (Step 3 voice):

Counseling priorities:

Cardiac rehab and lifestyle:

CCS pearl: order "anticoagulation clinic referral" or "pharmacy-led DOAC management" in the disposition phase — improves adherence and reduces 30-day readmissions.

Board pearl: annual creatinine in younger patients, semiannually if age >75 or CKD.

Ethical, Legal, and Patient Safety Considerations

— DOAC-ICH patients often cannot consent; reversal qualifies as emergency exception to consent — proceed and document

— Identify and contact surrogate decision-maker per state hierarchy as soon as possible

— When patient has a known advance directive declining "aggressive measures," reversal in life-threatening bleed may still be appropriate if the directive doesn't specifically address acute reversible bleeding — clarify with surrogate

— Large ICH with poor prognosis: weigh reversal vs comfort-focused care with family

— Document discussion explicitly; involve palliative care early in devastating ICH

— Anticoagulation resumption gaps are a major cause of recurrent stroke in AFib post-bleed — ensure clear date, dose, follow-up assignment, and pharmacy notification at discharge

— Use medication reconciliation at every handoff (ED → floor → discharge); DOAC errors (wrong dose, duplicate therapy, missed hold for procedure) are sentinel events

— Implement closed-loop communication with PCP within 48 h of discharge

— Apixaban underdosing in elderly (only 1 of 3 criteria met) is a documented patient safety hazard — leads to thromboembolism

— Rivaroxaban must be taken with food (≥15 mg) for bioavailability — counseling failure → drug failure

— Trauma resulting in ICH in elderly patient with possible elder abuse or neglect triggers adult protective services reporting in most states

— Falls assessment is required as part of Medicare quality metrics

— Andexanet's cost creates access disparities; institutional protocols should specify 4F-PCC as accepted alternative to avoid care variation

— Patient out-of-pocket DOAC cost is a leading cause of nonadherence — screen and refer to patient assistance programs

Informed consent in the obtunded/critical patient:

Goals-of-care discussions:

Transitions-of-care safety (high-yield Step 3):

Medication safety / wrong-dose prevention:

Mandatory reporting and documentation:

Cost and equity:

Board pearl: the right answer often involves "discuss with the family and document goals of care" alongside the clinical intervention — both/and, not either/or.

Step 3 management: before discharge, confirm DOAC affordability and pharmacy access — a $500/month copay drives nonadherence and recurrent stroke.

High-Yield Associations and Rapid-Fire Clinical Facts

— Dabigatran → idarucizumab 5 g IV (two 2.5 g boluses)

— Apixaban, rivaroxaban → andexanet alfa (low- or high-dose regimen based on dose/timing)

— Edoxaban → andexanet off-label; or 4F-PCC

— All Xa inhibitors with no andexanet → 4F-PCC 50 U/kg

— Warfarin → 4F-PCC + IV vitamin K 10 mg

— Heparin → protamine

— LMWH → protamine (partial, ~60–80%)

— Fondaparinux → no antidote (off-label rFVIIa)

— Idarucizumab = Fab fragment, binds dabigatran 1:1 with 350× thrombin affinity

— Andexanet = catalytically inactive Xa decoy, binds Xa inhibitors and TFPI

— REVERSE-AD: idarucizumab for dabigatran

— ANNEXA-4: andexanet for Xa inhibitor bleeds (observational)

— ANNEXA-I: andexanet vs usual care in DOAC-ICH (better hemostasis, more thrombosis)

Drug → reversal agent (memorize):

Mechanism quick-recall:

Trial names:

Thrombotic risk after reversal: ~5% (idarucizumab) to ~10% (andexanet)

Dabigatran is dialyzable; apixaban, rivaroxaban are not (high protein binding)

Andexanet causes heparin resistance ~24 h → use bivalirudin if heparinization needed

Idarucizumab contains sorbitol → caution in hereditary fructose intolerance

PT/INR is unreliable for Xa inhibitors; TT is sensitive for dabigatran (normal TT excludes meaningful drug effect)

Apixaban: lowest bleeding risk among DOACs in head-to-head observational data; preferred in CKD and post-GI-bleed

Mechanical valves and APS: DOACs contraindicated → use warfarin

Activated charcoal within 2 h of DOAC ingestion (overdose)

Step 3 management: AFib patient with recurrent bleeding despite optimization → LAA occlusion (Watchman) as alternative to lifelong anticoagulation.

Board pearl: if the stem mentions a hospital "without andexanet on formulary," the right answer is 4F-PCC 50 U/kg.

Board Question Stem Patterns

— 78F with AFib on dabigatran 150 mg BID, last dose 4 h ago, falls and presents with right hemiparesis. CT: left basal ganglia ICH. Cr 1.2. What's next?

— Answer: idarucizumab 5 g IV (two 2.5 g boluses) + neurosurgery consult + BP control

— 72M with AFib on apixaban 5 mg BID, last dose 2 h ago, presents with hematemesis, HR 120, SBP 85. Hgb 7. What's next?

— Answer: resuscitate with PRBCs, andexanet alfa high-dose regimen (800 mg bolus + 8 mg/min infusion), urgent EGD

— Patient on dabigatran develops AKI from sepsis; now oozing from IV sites and gums. Cr jumped from 1.1 to 3.5.

— Answer: idarucizumab 5 g IV + emergent hemodialysis

— Patient received andexanet 6 h ago, now needs emergent CABG for tamponade. What anticoagulant?

— Answer: bivalirudin (not heparin — andexanet causes heparin resistance)

— Apixaban patient with bleeding; "PT 12 s, aPTT 30 s — no drug effect, observe."

— Wrong — PT/INR is insensitive to Xa inhibitors; clinical scenario + last-dose timing drives decision

— Stable epistaxis controlled by pressure in a rivaroxaban patient → hold DOAC, local measures; no andexanet

— Community ED with rivaroxaban-related retroperitoneal bleed; andexanet not stocked.

— Answer: 4F-PCC 50 U/kg + IR embolization

— Asks about timing of anticoagulation resumption post-ICH in AFib.

— Answer: 1–4 weeks depending on hemorrhage size and stability; shared decision with neurology and cardiology

— Mechanical mitral valve patient prescribed dabigatran with thromboembolic stroke.

— Answer: the prescription was inappropriate; switch to warfarin

Classic ICH stem:

Classic GI bleed stem:

Renal failure trap:

Heparin resistance trap:

Test-of-choice trap:

Reversal-not-indicated stem:

Cost/access stem:

Post-reversal management stem:

Wrong-drug stem:

CCS pearl: when the stem says "while preparing reversal agent," that's a cue to continue parallel orders (blood, imaging, consults) rather than pausing.

One-Line Recap

For life-threatening bleeding or emergent surgery in a patient on a DOAC, reverse dabigatran with idarucizumab 5 g IV (two 2.5 g boluses) and reverse apixaban or rivaroxaban with andexanet alfa (low- or high-dose regimen based on dose and timing since last intake), using 4F-PCC 50 U/kg as alternative — always paired with source control, blood product resuscitation, and a deliberate plan to resume anticoagulation once hemostasis is durable.

Mechanism recap: idarucizumab is a Fab fragment that binds dabigatran 1:1 with 350× thrombin affinity; andexanet is a catalytically inactive factor Xa decoy that sequesters Xa inhibitors.

Decision recap: reverse only if (1) life-threatening bleed or emergent surgery, AND (2) DOAC taken within ~3–5 half-lives — do not anchor on PT/INR for Xa inhibitors; use last-dose history and clinical severity. Activated charcoal within 2 h of ingestion is a useful adjunct in overdose.

Complication recap: ~5–10% thrombotic event rate post-reversal; andexanet causes ~24 h heparin resistance (use bivalirudin for cardiac surgery/ECMO); dabigatran is dialyzable in renal failure while Xa inhibitors are not.

Disposition recap: ICU admit for all ICH and unstable bleeds; orchestrate neurosurgery/GI/IR consults early; restart anticoagulation 1–2 weeks post-ICH or 3–7 days post-GI bleed after source control, often switching to apixaban if recurrent GI bleeding; address fall risk, drug interactions, and renal monitoring at discharge; document shared decision-making about resumption.