Which leg immobilized patient gains the most from Intermittent Pneumatic Compression in DVT-prevention?

Background and method. Following Achilles tendon rupture (ATR)-surgery, patients using intermittent pneumatic compression (IPC) of the calf, compared to a plaster casted control-group (CTRL), exhibit reduced risk of deep venous thrombosis (DVT). Based on data from a randomized controlled trial (RCT), we investigated which dichotomized subgroups (based on age, sex, BMI and time to surgery (TTS)) within the IPC- (n= 66) and CTRL-group (n= 70) that were most likely to sustain a DVT, and which patients that had most benefit from postoperative IPC. Results. Age >39y (OR 6.06, p<0.001) and TTS >66h (OR 2.3, p=0.031) significantly increased the risk of DVT, but not sex or BMI. IPC-treatment significantly reduced the DVT-risk (OR 0.46, p=0.042), with more pronounced effect when considering age and TTS (OR 0.40, p=0.032). Although non-significant, females (OR 1.44, p=0.78) and patients with low BMI (OR 1.16, p=0.84) seemed to exhibit less DVT-preventive effect of IPC. Conclusion. Patients with age >38y and TTS>66h are at increased DVT-risk during post-operative leg immobilization, while adjuvant IPC shows good DVT-preventive effects among most patients, especially in those with high DVT-risk. Further trials are however warranted, to examine the low DVT-preventive effects of IPC discovered among females and patients with low BMI.