External vacuum expansion in autologous fat transfer as total breast reconstruction: Is it worth it? The interim analysis of the multicentre randomised controlled EVE trial

Background Autologous fat transfer (AFT) is an emerging option for total breast reconstruction. To improve graft survival, perioperative external vacuum expansion (EVE) is used to optimise recipient-site environment. However, the efficacy of EVE and its treatment burden on women needs consideration. This interim analysis of a multicentre randomised controlled trial (RCT) evaluates the effect of EVE on volumetric outcomes and safety. Methods Women undergoing total breast reconstruction with AFT were randomised 2:1 to perioperative EVE or no EVE. All participants underwent three AFT sessions followed by magnetic resonance imaging (MRI)-based volumetric assessment at six months. Primary outcomes were percentage augmentation and graft retention. Secondary outcomes included (serious) adverse events (SAEs). Quality-of-life (QoL) outcomes were not analysed in this interim analysis, as reconstruction was ongoing. Results Fifty-three participants were included (EVE, N = 32; control, N = 21). Mean augmentation was 190.7% with EVE versus 176.4% without (adjusted difference 14.6%; 95% CI -80.0 to 109.1; p = 0.757). Graft retention was 39.3% and 34.9%, respectively (difference 4.5%; 95% CI -6.4 to 15.4; p = 0.405). Both outcomes showed no statistically significant between-group differences. The EVE group experienced more AEs (22 AEs and 5 SAEs) compared with the control group (three AEs and two SAEs), which were predominantly skin-related complications. Conclusions Perioperative EVE use did not yield significant improvements in augmentation or graft retention; however, it was associated with higher treatment burden and more (S)AEs. Final analyses of our ongoing RCT, incorporating patient-reported QoL outcomes are still awaited. Based on this interim analysis, the clinical benefit of EVE in reconstructive settings remains uncertain and warrants additional research.