Aspirin mono-therapy continuation does not result in more bleeding after knee arthroplasty

Current clinical practice guidelines sometimes still recommend stopping aspirin five to seven days before knee arthroplasty surgery. Literature regarding multimodal blood management and continuation of anti-platelet therapy in this type of surgery is scant. The study hypothesis was that knee arthroplasty under low-dose aspirin mono-therapy continuation does not cause more total blood loss than knee arthroplasty performed without aspirin. Blood loss would be measured by haemoglobin (Hb) and haematocrit (HTC) levels drop at day 2 or day 4 for patients who benefit from multimodal bleeding control measures. A database of all patients undergoing knee arthroplasty between 2006 and 2014 was analysed. Demographic, surgical and complete blood workup data were collected. A retrospective comparison study analysed both groups in terms of blood loss, by mean calculated blood loss as haemoglobin or haematocrit drop between the preoperative Nadir value and the postoperative day 2 and 4 value. A group of 198 (44 UKA and 154 TKA) patients underwent surgery without interrupting their aspirin therapy for cardiovascular prevention. Mean (SD) age was 71 (8) and the mean (SD) BMI was 29 (5.5) kg/m 2 . The control group consisted of 403 (102 UKA and 301 TKA) patients who were not under aspirin, or any other anti-platelet agent. Mean (SD) age was 65 (10) ( p < 0.05) and the mean (SD) BMI was 29 (5.0) kg/m 2 (n.s.). All patients in the control group were randomly selected. There were no differences in terms of visible (early) or hidden (late) blood loss as measured by Hb drop in between both groups. There is no difference in transfusion rates. Modern multimodal blood management provides sufficient blood loss prevention during and after knee arthroplasty to allow physicians to continue low-dose aspirin mono-therapy for cardiovascular prevention. III.