Choosing & bridging anticoagulation

Choosing an anticoagulant

Guidelines first, then the patient in front of you: CHEST VTE (), ASH VTE (), ASCO cancer VTE (), ACC/AHA/HRS AF (), CHEST AF (), AHA/ACC valves ().

Three questions that pick the drug

Why
Indication
VTE, AF, mechanical valves, APS, and ACS are different licenses. A dose is not a PE dose.
Who
The host
Active cancer (especially GI/GU luminal tumors), post-bariatric anatomy, pregnancy, ESRD, and triple-positive APS change the winner.
When
The calendar
Bridging and hold times are a separate decision from the chronic agent. DOACs do not get a heparin .

VTE situation	Preferred agent	Do not
Most patients	DOAC > warfarin > LMWH	Start with an IVC filter because it is easier than anticoagulation
Obesity	DOAC still preferred unless post-bariatric surgery (Cass 2, ). If you use a DOAC after bariatric surgery, check peak/trough (ISTH: )	Assume every BMI >40 needs warfarin
Active malignancy	Apixaban (), edoxaban (), rivaroxaban (), or LMWH > warfarin (). Prefer LMWH for GI/GU cancer with an intraluminal lesion (apixaban bleeds less than edoxaban/rivaroxaban among the DOACs)	Pick rivaroxaban first for an active gastric mass
Cancer prevention	DOAC > LMWH for short-term treatment; either for long-term. Apixaban/rivaroxaban prophylaxis cuts VTE in high-risk outpatients; consider if Khorana ≥2 (; ). LMWH prophylaxis is acceptable in high-risk outpatients	Therapeutic enoxaparin as 'prophylaxis'
Recurrent VTE	On a non-LMWH: switch to LMWH. Already on LMWH: increase the dose by 1/4–1/3 and check anti-Xa	Add aspirin and hope
Everything else	Treat high-risk SVT (prior VTE, surgery, active cancer, clot within 3 cm of the saphenofemoral junction) (Lancet. 2017:e105-e113). Acute proximal DVT or severe distal DVT: 3 months, DOAC > VKA. IVC filter only if anticoagulation is contraindicated — then retrieve it	Leave a filter in 'just in case'

AF, valves, APS, and coronaries

Setting	Anticoagulant	Detail
Nonvalvular AF	DOAC > warfarin	Better stroke, mortality, and bleeding in the trials that built the class
Valvular AF (moderate/severe MS)	Warfarin, INR 2–3	Regardless of CHA2DS2-VASc. This is not a DOAC indication
Mechanical valve	Warfarin. DOACs not approved. +ASA for On-X aortic	INR goal AVR 2.5 (3 if AF, VTE, or other risk). Mitral/tricuspid 3
Bioprosthetic SAVR	Warfarin (INR 2.5) + ASA for 3–6 months, then ASA	TAVR: ASA/clopidogrel 3–6 months then ASA. If AF/VTE: OAC + clopidogrel then OAC (evolving)
APS	Warfarin	DOACs increased thrombosis versus warfarin across APS (), especially triple-positive

AF plus PCI

Dual therapy (P2Y12 inhibitor + oral anticoagulant) bleeds less than prolonged triple therapy (; ). Typical dual: OAC + clopidogrel for 6–12 months, then OAC alone ().

OAC options studied: rivaroxaban 15 mg daily (some use 20 mg) (); dabigatran 150 mg BID (); apixaban 5 mg BID or 2.5 mg BID (); edoxaban 60 mg daily (did not bleeding versus VKA) (); warfarin + clopidogrel ().
Ticagrelor may be used when thrombotic risk is very high ().
If you choose triple therapy (high thrombotic, low bleed risk), drop aspirin at 1–4 weeks and continue P2Y12 inhibitor + OAC.

CAD without AF

ACS with PCI: very-low-dose rivaroxaban 2.5 mg BID added to ASA/clopidogrel reduced CV mortality but increased major bleeding ().
Secondary prevention: rivaroxaban 2.5 mg BID + ASA improved CV outcomes versus ASA alone; more major bleeding but no increase in ICH or fatal bleeding (, ). Consider if event risk is high and bleed risk is low.
Post-PCI DAPT: 12 months remains common; 1–3 months DAPT then 12 months clopidogrel was non-inferior to 12 months DAPT (). The DAPT score can inform duration.

Bridging

the patients whose clot risk is high enough to justify a bleed (ACC: ; ASH: ; CHEST: ). Combine procedural bleed risk with HAS-BLED.

Thrombotic risk	AF — bridge?	VTE — bridge?	Mechanical valve — bridge?
High	CHA2DS2-VASc ≥7 (or CHADS2 5–6); CVA/TIA or systemic embolism <3 months; rheumatic valvular disease. Yes, unless major bleed/ICH <3 months	VTE <3 months; severe thrombophilia (protein C/S or ATIII deficiency, APS, multiple abnormalities). Yes	Any mechanical mitral valve; caged-ball/tilting-disc AVR; any mechanical valve with CVA/TIA <6 months. Yes
Moderate	CHA2DS2-VASc 5–6 (or CHADS2 3–4); CVA/TIA or embolism >3 months. Likely if prior CVA/TIA and bleed risk is not high	VTE 3–12 months, recurrent VTE, active malignancy, non-severe thrombophilia (heterozygous FVL, prothrombin gene). No	Bileaflet AVR with ≥1 stroke risk (age >75, AF, prior CVA/TIA, HTN, diabetes, HF). Weigh against procedural bleeding
Low	CHA2DS2-VASc ≤4 (or CHADS2 0–2) and no prior embolism. No	VTE >1 year and no other risk factors. No	Bileaflet AVR without AF or stroke risk factors. No

How to bridge a VKA (prefer LMWH if the kidneys allow)

5 d
Stop warfarin
Hold 5 days before the procedure if the INR is therapeutic.
INR <2
Start UFH or LMWH
Begin parenteral anticoagulation once INR falls below 2.
Day 0
Hold the bridge
Stop UFH 4–6 h pre-op. Stop LMWH 12 h (once daily) or 24 h (twice daily) pre-op.
Restart
Post-op
Restart UFH/LMWH at 24 h if post-procedural bleed risk is low, or 48–72 h if high. Stop the when INR >2. Resume warfarin within 24 h if there is no bleeding — it will not raise early bleed risk because the effect takes 24–72 h.

Holding a DOAC

DOACs do not need a heparin . Most can stop 24–72 hours before surgery, depending on bleed risk and renal function. Resume 24 h after a low-bleed procedure or 48–72 h after a high-bleed one. If the patient is NPO or more procedures are coming, use UFH/LMWH.

Call Book / MGH peri-procedural DOAC guidance for cath lab and IR procedures is institution-specific — use it when you are there.

Drug	High bleed, CrCl >50	High bleed, CrCl <50	Low bleed, CrCl >50	Low bleed, CrCl <50
Dabigatran	≥48 h (4 doses)	≥96 h (8 doses)	≥24 h (2 doses)	≥48 h (4 doses)
Rivaroxaban	≥48 h (2 doses)	≥48 h (2 doses)	≥24 h (1 dose)	≥24 h (1 dose)
Apixaban	≥48 h (4 doses)	≥48 h (4 doses)	≥24 h (2 doses)	≥24 h (2 doses)
Edoxaban	≥48 h (2 doses)	≥48 h (2 doses)	≥24 h (1 dose)	≥24 h (1 dose)