perioperative DVT prophylaxis

Orthopedic surgeries

  • Major orthopedic surgeries poses high DVT risks
  • Major orthopedic surgeries: hip arthroplasty, knee arthroplasty, hip fracture surgery
  • recommendation: 35 days of LMWH if no increased bleeding risk or bleeding complications
  • Other ortho surgeries: 10-14 days of ppx
  • If pt decline injection or can't tolerate: oral dabigatran, factor 10a inhibitor (apixaban, rivaroxaban), vitamin K antagonist (warfarin) are used as ppx
  • Isolated lower leg fracture repairs: no ppx
  • Knee arthroscopy with no previous VTE: Early ambulation

Perioperative Management of Anticoagulant Therapy

Pre op

  • AC can be continued in minor surgeries
    • dental extraction, skin surgery, cardiac device implantation
  • Most surgeries: discontinue AC
  • Warfarin: discontinue at least 5 days prior to surgery, goal INR < 1.5
  • DOACs: usually 2-3 days because shorter half lives
  • Bridging with heparin: usually with warfarin only

Post op

  • warfarin: usually not needed to bridge, can restart 12-24 hours after surgery
  • if need bridging: usually start 24 hours after surgery
  • high bleed risk: bridging delayed to 48 or 72 hours
  • DOAC: reach theapeutic levels in 1-3 hours, resume once hemostasis is ensured, usually 48-72 hours
  • avoid AC with spinal/epidural anesthesia due to risk for epidural hematoma

Atrial Fibrillation

The decision to initiate bridging anticoagulation in patients with atrial fibrillation is based on bleeding risk and thrombotic risk. Procedures with an intermediate or high risk for bleeding almost always require interruption of anticoagulation.

The landmark BRIDGE trial has shifted clinical practice toward a more conservative approach to bridging anticoagulation in patients with nonvalvular atrial fibrillation. This randomized controlled trial determined bleeding and thrombotic outcomes in patients who received bridging anticoagulation compared with those who did not. An increased risk for bleeding was identified in patients who received bridging anticoagulation, and those who received no bridging anticoagulation did not demonstrate an increased risk for thrombosis.

According to recent AHA/ACC and ACCP guidelines, preoperative bridging is not recommended in patients with atrial fibrillation taking warfarin without a mechanical valve or high risk for thromboembolism. Examples of high-risk conditions for thromboembolism include ischemic stroke, transient ischemic attack, or systemic embolism within the past 3 months.

Prosthetic Heart Valves and Venous Thromboembolic Disease

In patients receiving warfarin anticoagulant therapy for a mechanical prosthetic heart valve, continuation of anticoagulation is recommended when the surgical procedure is minor and bleeding can be managed. In patients undergoing surgery with a higher risk for bleeding, the 2017 ACC/AHA guideline on valvular heart disease suggests that bridging should be considered on an individualized basis in patients with a mechanical mitral valve, a mechanical aortic valve with thromboembolic risk factors, or an older-generation mechanical aortic valve. Bridging is not necessary in patients with a bileaflet mechanical aortic valve and no other risk factors for thrombosis. The ACCP provides similar recommendations for bridging anticoagulation in patients with prosthetic heart valves (Table 99).

Recommendations for bridging anticoagulation in those with a history of venous thromboembolism, including patients with thrombophilias, are included in Table 100.

Perioperative Management of Antiplatelet Medications

  • Question 61

The perioperative management of dual antiplatelet therapy (DAPT), comprising aspirin plus a P2Y12 inhibitor (clopidogrel, ticagrelor, or prasugrel), in patients with CAD depends on the presence of a bare metal or drug-eluting coronary stent, time since stent placement, and, to some degree, the indication for DAPT (stable ischemic heart disease [SIHD] or acute coronary syndrome [ACS] within the last year).

In patients who have a stent placed for SIHD, DAPT should be continued uninterrupted for at least 30 days after bare metal stent placement and a minimum of 6 months after drug-eluting stent placement. Elective surgery should be postponed during these time frames. However, if the risk of surgical delay exceeds the risk for stent thrombosis, discontinuation of the P2Y12 inhibitor can be considered after a minimum of 3 months in patients with a drug-eluting stent. Aspirin should be continued if at all possible, and DAPT should be restarted as soon as bleeding risk has sufficiency diminished.

In patients with recent ACS, the ACC and AHA recommend continuing DAPT for at least 1 year regardless of whether the ACS was managed with medical therapy or coronary stent placement. If surgery must be performed within this time frame, DAPT should optimally be maintained for a minimum of 6 months. If more than 3 months have passed and the patient cannot be continued on DAPT because of bleeding risk, proceeding with surgery can be considered if the risk of surgical delay is greater than the risk for stent thrombosis.

In patients with recent percutaneous coronary intervention with stent placement for ACS in whom surgery mandates discontinuation of DAPT, aspirin should be continued. In patients with recent ACS treated medically who must undergo surgery for which DAPT must be discontinued, it is similarly reasonable to continue aspirin when the risk for cardiac events outweighs the risk for bleeding.

In most patients receiving long-term aspirin monotherapy for both primary and secondary prevention of cardiovascular events (in the absence of a coronary stent), aspirin should be discontinued at least 5 days before surgery and restarted postoperatively once bleeding risk has decreased. This recommendation is based on the POISE-2 trial, which found that continued perioperative aspirin resulted in increased bleeding without a decrease in cardiac events.

Perioperative Management of Anemia, Coagulopathies, and Thrombocytopenia

In all patients undergoing surgery, a careful preoperative bleeding history, including a family history, should be obtained to evaluate for underlying bleeding disorders and anemia. Laboratory testing should be reserved for patients with a suggestive history. Patients with known factor deficiencies, platelet function defects, and other coagulopathies should be managed by a hematologist.

In orthopedic and cardiac surgery patients and those with a history of stable CAD, the American Association of Blood Banks recommends a restrictive transfusion threshold (hemoglobin level of 8 g/dL [80 g/L]), as studies indicate that a restrictive threshold results in equivalent or improved patient outcomes. Similarly, in hospitalized hemodynamically stable patients, a transfusion threshold of 7 g/dL (70 g/L) is recommended.

The American Association of Blood Banks recommends a platelet transfusion threshold of 50,000/µL (50 × 109/L) for patients undergoing major non-neurologic surgery or lumbar puncture. Patients with mild thrombocytopenia due to immune thrombocytopenia are typically able to proceed to surgery at the recommended threshold. Postoperative thrombocytopenia warrants further evaluation, especially in patients with heparin exposure owing to the risk for heparin-induced thrombocytopenia. See MKSAP 18 Hematology and Oncology for a discussion of heparin-induced thrombocytopenia.