DVT Prophylaxis in Patients on Dual Antiplatelet Therapy

Introduction to DVT Prophylaxis

Combining anticoagulants with antiplatelet therapy significantly increases bleeding risk, as both aspirin and clopidogrel already provide some antithrombotic effect 1, 2
The American Society of Hematology (ASH) guidelines suggest suspending even single antiplatelet therapy (aspirin) when initiating anticoagulation for VTE treatment due to increased bleeding risk 3

Antiplatelet therapy (including aspirin) has some efficacy for VTE prevention, reducing PE risk by about one-half and DVT by about three-fifths in high-risk surgical or medical patients 4
Anticoagulants like LMWH are more effective than antiplatelet agents for VTE prophylaxis, with heparins reducing PE risk by about two-thirds 4, 1
The American College of Chest Physicians (ACCP) and French guidelines specifically advise against using aspirin as the sole method of thromboprophylaxis (Grade A and B recommendations, respectively) 5, 6

For patients on dual antiplatelet therapy, the American Society of Hematology (ASH) recommends assessing VTE risk and evaluating bleeding risk to determine the best approach for DVT prophylaxis 4, 5
The American College of Chest Physicians (ACCP) suggests that patients with high VTE risk and high bleeding risk should use mechanical prophylaxis without pharmacological agents 5, 1

In orthopedic settings, some guidelines (AAOS, SIGN) do recommend aspirin as thromboprophylaxis, but this is controversial and not universally accepted 5, 6
For patients already on DAPT undergoing orthopedic procedures, mechanical prophylaxis should be the primary approach 5
In critically ill COVID-19 patients, guidelines specifically recommend against using antiplatelet agents for VTE prevention 1