# Platelet Aggregation Inhibitors and Anticoagulants Delay Surgery for Hip Fractures
## 4 Discussion  
Platelet aggregation inhibitors and anticoagulant use at the time of hospital admittance for a fragility hip fracture is high. In our study population, almost one-third of patients were using some form of antithrombotic medication. This had a significant effect on the delay of surgery. We offer a local perspective from a single level 1 trauma center. Time to surgery, use of platelet aggregation inhibitors and anticoagulant medication and type of anesthesia have regional differences [1; 2; 3; 4; 5; 6; 7; 8]. [PERSON] et al. found that antithrombotic medication use in general increased 2.3 times from 19% to 43%, with the highest increase seen for anticoagulants. Age, sex and higher Charlson index were associated with the use of antithrombotic medication [4]. Hip surgery consists of either fracture fixation or arthroplasty. It is considered a delayed emergency/major surgery with a high risk of bleeding. For anticoagulated patients, the delay is based on the type of blood-thinning medication used, current guidelines and product label information: acetylsalicylic acid--no delay; clopidogrel--5 days for neuraxial anesthesia, less for orthopedic surgery; acenocoumarin--INR \(<\) 1.5 for neuraxial anesthesia, higher values for orthopedic surgery yet no consensus regarding cut-off value; patients with an INR \(>\)3 should receive oral vitamin K; apixaban, rivaroxaban and dagigatran--2 to 5 days with more caution required for neuraxial anesthesia than for orthopedic surgery [1; 5; 6]. The most used platelet aggregation inhibitors are acetylsalicylic acid and clopidogrel. Recent guidelines consider that platelet aggregation inhibitor agents should not interfere with timing of surgery but may dictate the choice of anesthesia. Currently there is strong evidence that acetylsalicylic acid does not increase the risk of bleeding during major surgery or regional anesthesia. On the other hand, clopidogrel should be stopped for 5 days before regional anesthesia such as spinal, epidural or peripheral nerve blocks [5; 6]. Nonetheless, in our study, even patients on acetylsalicylic acid had a longer delay of surgery compared to controls. A study by [PERSON] et al. showed a wide variability among orthopedic surgeons regarding management of patients with hip fracture on clopidogrel [10]. Over a quarter of surgeons continued to opt for surgery postponement even though there appears to be no difference in total blood loss, transfusion rate, or 1-year mortality among patients receiving platelet aggregation inhibitor medication [10; 11; 12]. Vitamin K antagonists (warfarin, acenocoumarin) and DOACs (inhibitors of factor IIa or Xa) are the most used anticoagulants. Vitamin K antagonists coagulopathy is usually reversed by administration of phytomenadione. An INR \(<\) 1.5 is considered safe for elective major surgery. Hip fracture patients on vitamin K antagonists are more likely to have increased time to surgery, blood loss, length of stay and mortality up to 1 year [13; 14]. However, a study by [PERSON] et al. observed that hip fractures admitted on warfarin seem to be at similar risk of transfusion or adverse events compared with nonanticoagulated patients. Waiting for INR normalization only delayed surgery without reducing blood loss or preventing complications. They conclude that one may consider proceeding with surgery in patients with INR above 1.5 if patients are otherwise medically optimized, but to what upper limit is currently unknown [15]. In a large cohort, vitamin K antagonists and DOACs did not increase the 30-day postoperative mortality among hip fracture patients. A subset analysis found that DOACs increased the risk of transfusion and platelet aggregation inhibitors increased the risk of both transfusion and mortality [16]. Several other recent studies identified approximately 9-16.6% of hip fracture patients to be anticoagulated. However, the absolute number of DOACs cases was relatively low [17; 18; 19; 20]. In our study 9.9% were anticoagulated.