Rivaroxaban for Venous Thromboembolism Prophylaxis in Abdominoplasty: A Multicenter Experience

BACKGROUND: Abdominoplasty, a commonly performed aesthetic procedure, is considered to have an increased risk of venous thromboembolism (VTE) events. At present, routine VTE chemoprophylaxis following abdominoplasty remains controversial. OBJECTIVES: This study evaluates the authors' experience with rivaroxaban, an oral Factor Xa inhibitor, for VTE prophylaxis in abdominoplasty patients. METHODS: A retrospective case series was conducted. All patients who underwent abdominoplasty and received rivaroxaban were included. The prophylactic dose was 10 mg daily for 7 days, beginning 12 hours postoperatively. Patient demographics, comorbidities, and type of surgery were recorded. The primary outcome measured was hematologic complication, including VTE, hematoma requiring operative evacuation, and need for blood transfusion. RESULTS: From September 2012 until July 2014, 132 patients (122 women and 10 men) underwent abdominoplasty surgery and received rivaroxaban postoperatively. Mean patient age was 43.7 years, and mean body mass index was 27.1. One hundred twenty-five patients also underwent abdominal muscle plication. Eleven patients underwent a fleur de lis vertical skin resection component. One hundred patients underwent concomitant abdominal liposuction, while 79 patients also had back liposuction. Only 1 patient had a symptomatic VTE event. Three patients had a hematoma requiring operative evacuation, and all went on to heal without sequelae. Two patients received a blood transfusion for anemia during their course of rivaroxaban. CONCLUSIONS: Oral rivaroxaban administration for chemoprophylaxis in abdominoplasty patients is safe, with low rates of symptomatic VTE and hematoma formation. The authors continue routine use of the medication for patients at increased risk for VTE events. LEVEL OF EVIDENCE 4: Risk

Coronal Heating as Determined by the Solar Flare Frequency Distribution Obtained by Aggregating Case Studies

Flare frequency distributions represent a key approach to addressing one of the largest problems in solar and stellar physics: determining the mechanism that counter-intuitively heats coronae to temperatures that are orders of magnitude hotter than the corresponding photospheres. It is widely accepted that the magnetic field is responsible for the heating, but there are two competing mechanisms that could explain it: nanoflares or Alfv\'en waves. To date, neither can be directly observed. Nanoflares are, by definition, extremely small, but their aggregate energy release could represent a substantial heating mechanism, presuming they are sufficiently abundant. One way to test this presumption is via the flare frequency distribution, which describes how often flares of various energies occur. If the slope of the power law fitting the flare frequency distribution is above a critical threshold, $\alpha=2$ as established in prior literature, then there should be a sufficient abundance of nanoflares to explain coronal heating. We performed $>$600 case studies of solar flares, made possible by an unprecedented number of data analysts via three semesters of an undergraduate physics laboratory course. This allowed us to include two crucial, but nontrivial, analysis methods: pre-flare baseline subtraction and computation of the flare energy, which requires determining flare start and stop times. We aggregated the results of these analyses into a statistical study to determine that $\alpha = 1.63 \pm 0.03$. This is below the critical threshold, suggesting that Alfv\'en waves are an important driver of coronal heating.Comment: 1,002 authors, 14 pages, 4 figures, 3 tables, published by The Astrophysical Journal on 2023-05-09, volume 948, page 7