Risks of thromboembolism (TE) by condition:

Chronic A-fib:
- Low Risk (<5%/yr): CHADS2 score 0-2 and no hx prior stroke or TIA. 

- Mod Risk (5-10%/yr): CHADS2 score 3-4 and no high risk condition. 

- High Risk (>10%/yr): CHADS2 score 5-6, or recent (within 3 mos) stroke or TIA, or rheumatic valvular heart dz.

Mechanical Heart Valve:
- Low Risk (<4%/yr): bileaflet aortic valve prosthesis, no a-fib, no stroke risk factors (HTN. DM, CHF, age 75). - Mod Risk (4-10%/yr): bileaflet aortic valve prosthesis and one of: (1) a-fib; (2) prior stroke or TIA; and (3) at least one stroke risk factor (HTN, DM, CHF, age >75).

- High Risk (>10%/yr): one or more of: (1) any mitral valve prosthesis; (2) any caged-ball or tilting disk aortic valve prosthesis; and (3) recent (within 6 months) stroke or TIA.

Prior Venous Thromboembolism (VTE):
- Low Risk: VTE occurred > 12 months ago and no moderate or high risk issues/factors (see below).

- Mod Risk: VTE within the past 3 to 12 months, non-severe thrombophilic conditions (heterozygous carrier of factor V Leiden mutation or prothrombin gene mutation), recurrent VTE, or active cancer (treated within 6 months or palliative).

- High Risk: recent (within 3 months) VTE or severe thrombophilic conditions (deficiency of protein C, protein S or antithrombin; antiphospholipid antibodies; or multiple thrombophilic abnormalities). Patients who have had prior VTE after surgery might be considered high risk depending on the type of surgery they are undergoing (and the associated thromboembolic risk) and perioperative antithrombotic management should be individualized.

Stop Warfarin approx 5 days before surgery (1C). Allow INR to return to near normal. If INR still elevated (i.e. > 1.5) on day before surgery, low dose oral Vit K 1-2.5 mg is suggested.When surgical hemostasis is adequate, resume Warfarin 12-24 hours post-op (i.e. the evening after surgery or the next morning) (2C).

Stop Warfarin appx 5 days before surgery (1C). Allow INR to return to near normal. If INR still elevated (i.e. ≥ 1.5) on day before surgery, low dose oral Vit K 1-2.5 mg is suggested.

Patients with moderate thromboembolic risk are a difficult category. ACCP outlined how there is particularly little clarity from the literature to guide the decision whether to provide bridging therapy. They recommend that the decision be made on a case-by-case basis balancing the details of thromboembolic risk and surgical bleeding risk (2C). For instance, in procedures with high bleeding risks (examples can be viewed on bottom of ‘High Risk TE’ section), one might be disposed against bridging therapy, while when surgery has low bleeding risk and/or anticoagulation indications are particularly strong, one may be disposed towards bridging therapy. If one elects bridging therapy, follow the recommendations in the ‘High Risk TE’ section. Without bridging, these patients are managed like low risk patients, as described here and on the ‘Low Risk TE’ section.

When surgical hemostasis adequate, resume Warfarin 12-24 h post-op (i.e. the evening after surgery or the next morning).

There is new evidence which should prompt reconsideration whether to bridge those with moderate thromboembolic risk. Since the ACCP 2012 periop anticoagulation guideline publication, three significant studies have been published.

In the BRIDGE trial (Douketis NEJM 2015), 1,884 patients with A-Fib on Warfarin at moderate thromboembolic risk were randomized to bridging or no bridging. Bridging prevented no thromboemb events and increased major bleeding

In the RE-LY trial sub-study analysis (Douketis Thromb-Haem 2015), a cohort study of 4,133 A-Fib patients on Warfarin or Dabigatran with ≥ 1 CHADS2 risk factor received bridging or no bridging. Bridging prevented no thromboemb events and increased major bleed.

Finally, there was a systematic review & meta-analysis of 34 studies (1 RCT) showing no benefit and increased bleeding from bridging (Siegal Circ 2012).

Thus it appears that the preponderance of evidence leans away from bridging for the moderate risk group. Pay attention to the next ACCP updated periop anticoagulation guidelines.

Stop Warfarin approx 5 days before surgery (1C). Allow INR to return to near normal. If INR still elevated (i.e. > 1.5) on day before surgery, low dose oral Vit K 1-2.5 mg is suggested.

During temporary interruption of Warfarin, give bridging anticoagulation with therapeutic-dose SC LMWH or IV UFH. For bridging anticoagulation with LMWH, administer the last dose of LMWH 24 h before surgery (2C) and make that last preop LMWH dose approx half the regular full daily dose if daily dosing regimen used. For bridging anticoagulation with therapeutic-dose IV UFH, stop UFH approximately 4-6 h before surgery (2C).

Post-op, there are two considerations for anticoagulation, resumption of Warfarin and bridging heparin.

When surgical hemostasis adequate, resume Warfarin 12-24 h post-op (i.e. the evening after surgery or the next morning) (2C).

Post-op bridging heparin is trickier because of the risk of serious post-op bleeding. ACCP recommends considering the anticipated bleeding risk and adequacy of post-op hemostasis in individual patients to determine the timing of LMWH or UFH resumption after surgery instead of resuming LMWH or UFH at a fixed time after surgery in all patients. In patients undergoing a surgical or invasive procedure, considered non-high-bleeding-risk, resume LMWH or UFH regimen approximately 24 h after (i.e., the day after) the procedure when there is adequate hemostasis (2C).

High-bleeding-risk procedures are those in which post-op bleeding is more likely or when such bleeding poses particularly serious consequences. These procedures include (but are not limited to):

– urologic surgery like TURB, bladder rsxn, or tumor ablation; nephrectomy, or kidney bx

– pacemaker or implantable cardioverter-defibrillator device placement

– colon polyp rsxn, typically of large and/or sessile polyps

– surgery in highly vascular organs, such as the kidney, liver, and spleen

– bowel rsxn in which bleeding may occur at the anastomosis

– major surgery with extensive tissue injury (e.g., cancer surgery, joint arthroplasty, reconstructive plastic surgery)

– cardiac, intracranial, or spinal surgery, especially as small pericardial, intracerebral, or epidural bleeds can have serious consequences

Minor dental procedures (2 options):

– continue Warfarin around the time of the procedure and coadminister an oral prohemostatic agent (i.e. surgical glue, tranexamic acid mouthwash, sutures, etc.); or

– stop Warfarin 2-3 days before procedure (2C).

Minor Dermatologic procedures:

– continue Warfarin and optimize local hemostasis (2C).

Cataract removal:

– continue Warfarin