| Level I | Good quality evidence |
Systematic review of RCTs with consistent findings High quality individual RCT |
| Level II |
Limited quality patient orientated evidence |
Systematic review of lower quality studies or studies with inconsistent findings Low quality clinical trial Cohort studies Case-control studies |
| Level III | Other |
Consensus guidelines, extrapolations from bench research, usual practice, opinion, disease-oriented evidence (intermediate or physiologic outcomes only), or case series |
[35] Timing of anticoagulants: The BRIDGE Study Investigators .Bridging Anticoagulation: Is it Needed When Warfarin Is Interrupted Around the Time of Surgery or a Procedure? Circulation 2012;125:e496-e498. http://www.ncbi.nlm.nih.gov/pubmed/22451610
Timing of anticoagulants: Horlocker TT, Vandermeuelen E, Kopp SL, Gogarten W, Leffert LR, Benzon HT. Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (Fourth Edition). Reg Anesth Pain Med. 2018 Apr;43(3):263-309. https://www.ncbi.nlm.nih.gov/pubmed/29561531