One discussion this week involved how soon after cardiovascular surgery to restart VTE prophylaxis heparin.

Reference: Ho KM, Bham E, Pavey W. Incidence of venous thromboembolism and benefits and risks of thromboprophylaxis after cardiac surgery: A systematic review and meta-analysis. Journal of the American Heart Association. 2015 Oct 26;4(10):e002652. doi: 10.1161/JAHA.115.002652.

Summary: A systematic review and meta-analysis (Ho et al, 2015) found no evidence to support the notion that use of low-dose UFH or LMWH for VTE prophylaxis would increase risk of cardiac tamponade, pericardial effusion, or bleeding after cardiac surgery. Though these complications are not rare after surgery, whether low-dose UFH or LMWH would substantially increase such risks remains scientifically unproven (p.21).

Bleeding after cardiac surgery is mainly related to systemic overanticoagulation or concurrent use of systemic anticoagulation and platelet agents. The AHA document concludes that, unless proven otherwise by adequately powered RCTs, initiating low-dose UFH or LMWH as soon as possible or on postoperative day 1 after cardiac surgery for patients who have no active bleeding is highly recommended, especially if they have multiple risk factors for VTE.

Additional Reading: Agnelli G. Prevention of venous thromboembolism in surgical patients. Circulation. 2004;110(24, supp1):IV-4-IV-12. doi: 10.1161/01.CIR.0000150639.98514.6c