P2. fat graft pulmonary embolism: in favour of a lymphatic route

PURPOSE: Fat Pulmonary Embolism Syndrome (F-PES) complicates high-volume fat grafting. Adipocyte disruption generates triglyceride (TGC) oil dispersed in lipoaspirate (lipocrit). TGC plasma concentration ([TGC]p) was compared with lipocrit during liposuction-lipografting procedures. 1 buttock grafting case suffered a F-PES that required ICU support. METHODS: n=27 (19 breast, 8 buttocks) lipocrit recorded and ([TGC]p) measured in peripheral blood samples preoperatively, intra and 24h postoperatively. F-PES patient underwent right subclavian vein access (SVC) and Inferior Vena Cava (IVC) at ICU admission RESULTS: Lipocrit (200-600 cc graft volume) ranged 19-27%.Peripheral [TGC]p pre-, intra- post- and at 24h displayed no significant differences for all cases. In the F-PES case, SVC drawn [TGC]p was 7-fold higher than that from simultaneously drawn IVC or peripheral samples and returned to normal peripheral levels 48 h later. These unexpected data prompted measurement of:Critical Micelle Concentration (CMC) of fat graft oil when mixed in either lymphatic (chylous, CMCc) or plasmatic (CMCp) fluids. CMCp was consistently higher than CMCc (CMCc=110 mg/dL, CMCp=320 mg/dL, n=17, P<0.001).Interstitial Pressures (IP) both intramuscular (im) and subcutaneous (sc) at recipient sites. IPsc raised to pressures below 50 mmHg and returned to baseline within 24 h. IPim raised above 50 mmHg and persisted CONCLUSION: F-PES appears associated to increased [TGC]p detectable at the SVC only. TGC micelle formation is thermodynamically adverse in plasma versus chyle, suggesting a preferential lymphatic uptake of grafted oil at the recipient site. This lymphatic uptake could be favored when graft oil is implanted im, where IP-im reach pressures that prevent venous drainage.