A new evidence-based guideline was just published on Chest 2012, summarizing the best approach to anticoagulation in a number of different scenarios. Overall, the new recommendations are more conservative than before regarding anticoagulation peri-procedure.To illustrate that, let’s use a theoretical patient on anticoagulation with coumadin (6mg daily) due to Factor of V Leiden mutation and prior history of thrombosis (more than 6mo ago).In preparation for the procedure, the physician would recommend stopping coumadin 5 days prior to the kidney biopsy and bridging with either UFH or LMWH. This is usually started on day 3 prior to the procedure. The major difference in approach now is related to when should the bridging anticoagulation be stopped and restarted. The novel guidelines recommend the following:
* If on IV heparin, stop infusion 4-6 hours prior to procedure* If on LMW, last dose should be 24 hours prior to procedure (rather than 12 hours before)* Resuming coumadin should occur 12-24 hours after procedure if no evidence of bleeding
* Bridging anticoagulation with LMWH or UFH should be restarted 48-72 hours after the procedure (rather than 24 hours after surgery). Since most of the bleeding after kidney biopsy will occur in the f irst 24 hours , I believe delaying for another 24 hours would only be warrant in major surgeries with higher bleeding risks)Most of these recommendations are grade 2C (weak), therefore individual interpretation is warranted.My take-home summary of anticoagulation peri-kidney biopsy in high risk patients for thromboembolism would be:
Stop coumadin 5 days before procedure; admit the patient with renal failure 3 days prior to biopsy for bridging with UFH; stop UFH at least 4 hours prior to procedure; resume coumadin/UFH 24-48 hours after bx if no evidence of bleeding (stable Hb, vital signs and no significant hematuria).Though this is a general suggested approach, remember to assess the thromboembolic risk for each individual patient before proceeding with a kidney biopsy.Below additional general recommendations about anticoagulants from the new guidelines:
- Dosing of UFH: 80U/kg bolus followed by 18U/kg/hour- Dosing of coumadin: loading with 10mg daily for first 2 days [[personal opinion: this loading dose may be too high for elderly or cachetic patients]]- Dosing of enoxaparin: 1mg/kg BID; if GFRb below 30 ml/min: 1mg/kg daily - Dosing of fondaperinox: 5mg daily if less than 50kg; 7.5mg if 50-100kg and 10mg if more than 100kg. Avoid if GFR less than 30 ml/min.
- Dosing of dalterapin : 200 U/kg daily. Accumulation expected in renal failure but no specific dose adjustment has been recommended, so should likely be avoided until trials available.- Despite recent publications about benefits of genotyping in predicting response to coumadin, the guidelines recommend against this practice.