Commentary on: Macro Fat Embolism After Gluteal Augmentation With Fat: First Survival Case Report

Buttock augmentation is now one of the fastest growing aesthetic procedures in the United States according to The American Society for Aesthetic Plastic Surgery, with 26,774 performed in 2018, a 61.1% increase since 2014,1 and over 300,000 buttock augmentations with fat transfer performed worldwide in 2017 according to latest statistics from The International Society of Aesthetic Plastic Surgery,2 despite its poor safety record. A 2017 worldwide survey of 198,857 cases from 692 surgeons’ cases of gluteal fat grafting revealed 103 nonfatal pulmonary fat embolisms (PFE), a rate of 1:1931. There was no information about the type of embolus or treatment of those cases. PFE resulted in 32 deaths and an extrapolated mortality rate varying from 1:2350 to 1:6214 depending on the data source. The calculated total rate of fatal or nonfatal PFE was 1:1473.3 The mortality rate was 10 to 20 times greater than the 1:49,600 in the latest publication for all aesthetic surgical procedures in American Association for Accreditation of Ambulatory Surgery Facilities (AAAASF) facilities.4 The rate in nonaccredited facilities is unknown and may be significantly higher. The mortality is generally from macro (macroscopic) fat embolism (MAFE), never reported in any other aesthetic procedure, and is similar to pulmonary thromboembolism (PTE). PTE and MAFE resulting from fat injection into the gluteal muscle have similar behaviors because the pathophysiology includes an acute obstruction of the right cardiac cavities, pulmonary arteries, and the pulmonary vasculature. Hypoxia, hypotension, and bradycardia appear in both. But there are differences. In MAFE following lipoinjection, the onset of signs is simultaneous to almost immediately after the lipoinjection, whereas it usually occurs several days later in PTE. The understanding of macroscopic fat embolisms is insufficient because most cases are not reported. MAFE does not occur after 24 hours, which is common with PTE.5 Treatments with anti-coagulants and thrombolytic medications exist for PTE but not for MAFE, and surgical thrombectomy has been successfully performed following early detection but has not been employed for MAFE. MAFE is distinctly different from fat embolism syndrome (FES), which is a systemic inflammatory response usually from micro (microscopic) fat embolism (MIFE) that occurs in trauma cases, long bone fractures, and other orthopedic procedures that may have preexisting contribution. In contrast, buttock augmentation patients are usually healthy, young, and female.5 Although there have been few reports of microscopic fat in vessels with liposuction alone, not all develop FES. MAFEs have not occurred with liposuction alone. MIFE and MAFE have the same causal agent, but their pathogenesis, clinical evolution, treatment, and prognosis are totally different. Microscopic fat embolism has a 10% mortality rate when early treatment is established. That can rise to 35% following late treatment. In contrast, macro mortality is almost 100%.6 In MAFE, large fat particles (lethal intravenous injection of fat ranging from 15 to 50 mm) enter through a vein laceration, usually from intramuscular injection (any injection beneath the muscle fascia can result in fat extending deep) and travel through the vena cava into the right cardiac chambers. They cannot pass through the pulmonary vessels and remain lodged in the right cavities of the heart and form intra-cardiac emboli, resulting in acute heart failure. The authors stated that aggressive cardiac massage can break large fat emboli into smaller micro emboli; however, both can occur simultaneously. Micro fat particles can reach and obstruct the pulmonary vessels and cause pulmonary fatty embolism from multiple small vein injuries, which can produce a significant occlusion and inflammation of the arterial pulmonary vasculature. FES can cause a clinical picture of acute respiratory distress syndrome.7 Once fat emboli enter the circulation, they trigger a cascade of inflammatory and thromboembolic events that lead to release of free fatty acids into the circulation that stimulates the release of inflammatory mediators such as C-reactive protein; this then causes rapid production of fibrin aggregation of platelets resulting in fat globules. Respiratory abnormalities are the most common manifestation in patients with FES.8 Regarding MIFE, it has been recommended that hydration is essential in liposuction to clear free fatty acids, although there are no data to support that. The authors report on the first case of survival and recovery in a patient with MAFE from gluteal augmentation with fat.7 Following an onset of hypotension, bradycardia, and hypoxemia, the case was quickly terminated and resuscitation started. Treatment included chest compressions as well as ionotropic and vasopressor support during transfer to an intensive care facility. A bedside echocardiogram showed right ventricular dysfunction due to increased afterload and increased pulmonary pressures. CT of the chest was compatible with macroscopic fat embolism. The patient developed acute respiratory distress syndrome, survived, but suffered long-term dyspnea.7 Survival depended on early detection, aggressive cardio/respiratory support, and rapid transfer to an intensive care unit. Intravenous fat injections in pig models show there is immediate deterioration following fat embolism and then apparent clinical improvement between 10 and 30 minutes, which can create a false sense of security, but then deterioration from 30 to 60 minutes resulting in death.6 Surgery should and was terminated quickly. In general, prevention by following the guidelines from the Aesthetic Surgery Education and Research Foundation task force—further modified and supported by The Multi-Society Task Force for Safety in Gluteal Fat Grafting—is probably the only way to reduce mortality in MAFE until there is a modality to lyse or remove the embolus: Avoid injecting into muscle at all. Use ≥4.1-mm diameter single-hole injection nonflexible cannula. Avoid downward angulation of the cannula. Position patient and place incisions to create a path that will avoid muscle injections. Maintain constant 3-dimensional awareness of the cannula tip. Only inject when cannula is in motion. Consider PFE in unstable intra- and postoperative patients. Review gluteal vascular anatomy. Include the risk of fat embolism and surgical alternatives in the informed consent.3,9 Some have advocated injecting smaller amounts, but it has been shown that the risk of fat embolism with regard to relation of volume is a myth.10 The authors utilized the lateral decubitus position but now suggest avoiding that position to refrain from directing the cannula to the gluteal vessels in the dangerous deep medial area. The key factors are the level of injection and knowing the location of the cannula tip. A 3-mm cannula was formerly employed to inject both intramuscular and subcutaneous planes, whereas it is now recommended to inject only into the subcutaneous plane with a larger cannula. This article contributes to our knowledge of the resuscitation of patients with onset of MAFE. How many MAFE have occurred and whether there are other survivors is unknown because these complications often are not published in the literature or reported from facilities that do not require mandatory reporting of complications. A registry of these procedures would provide valuable data. For both MIFE and MAFE, the most important priority should always be patient safety, which can be further improved by having the procedures performed only by board-certified plastic surgeons in accredited or licensed surgical facilities. It is critical to have an anesthesiologist aware of the potential risks and to have a transfer agreement with a local hospital if it is performed in an ambulatory surgical facility. Even that will not bring the complication rate to zero. Increasing research in anatomical studies by many excellent concerned aesthetic surgeons and following the suggested guidelines appear to be making the procedure safer, which is critical. Only time and data will confirm if that will occur. In the interim, individual plastic surgeons and patients will decide whether the risk of performing the procedure is worth it and what is an acceptable risk for an elective aesthetic procedure.11 Some surgeons have given up the procedure because of the excessive risk. The author declared no potential conflicts of interest with respect to the research, authorship, and publication of this article. The author received no financial support for the research, authorship, and publication of this article.