Kidney biopsy is considered the most invasive procedure nephrologists are involved. Though complication rates are small, bleeding requiring surgery has been reported to occur in 1 in 1,000 kidney biopsies. More commonly, patients may develop a decrease in hemoglobin by 1 point (~50% of cases) and/or gross hematuria (3-18%). The risk of bleeding complications become much higher in patients that require peri-biopsy anticoagulation.
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 first 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 6-24 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. As an example, I would favor restarting anticoagulation much earlier after bx in a patient with history of multiple clots (6 hours after 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.