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Class Syndrome,” in which a relatively dehydrated person who is immobile for extended periods of time in a cramped airplane seat develops an in-flight DVT, is well known.44-46 One landmark series of studies (LONFLIT 1 and 2) performed screening duplex ultrasounds on asymptomatic people before and after trans-Pacific flights. This series of studies clearly demonstrated that 4.9% of people develop asymptomatic deep or superficial venous thrombosis during their flight, and in a followup study, that below knee elastic compression stockings worn during flight can significantly decrease the rate of asymptomatic DVT by nearly 20-fold (4.5% to 0.24%).44 A subsequent systematic review of VTE prevention specific to air travel showed that elastic compression stockings, but not aspirin or low molecular weight heparin, were associated with significant DVT risk reduction.45 Thus, patients who travel by air to their surgical procedure would benefit from utilization of elastic compression stockings. Of note, these data highlight the clinical ambiguity of asymptomatic DVT detected by screening ultrasound— using the LONFLIT data as examples, 1 person in 20 does not proceed directly from the airport to the hospital with symptomatic DVT. This is because the clinical relevance of asymptomatic clots is unclear, and the body’s existing thrombolytic mechanisms may dissolve a large proportion of these clots before they become symptomatic. In fact, the most recent American College of Chest Physicians guidelines explicitly advocate against screening ultrasound in asymptomatic patients (even high-risk abdominal and pelvic cancer patients and trauma patients),47 noting that the clinical relevance of asymptomatic DVT is unclear.48 Screening ultrasound after aesthetic surgery is further discussed below. Additional Preoperative Considerations Individualized VTE risk stratification proactively identifies patients at high risk for VTE. Fortunately, existing data support that these patients comprise 1% to 2% or less of the overall aesthetics population.33,34 Identification of these patients is important because it provides surgeons with the opportunity to preemptively manage VTE risk. Similarly, the informed consent process regarding VTE risk may be more robust when a patient’s risk is better quantified and conceptualized. Patients at high risk for VTE, specifically those with Caprini scores of 7-8 or >8, have significant VTE risk reduction with provision of chemical prophylaxis,2,32 although this has not been shown explicit to the ambulatory aesthetic population. For high-risk patients, preoperative hematology consultation can be considered (but is by no means mandatory) if patients have family member(s) with VTE or other notable risk factors. When chosen, preoperative consultation is ideal because hypercoagulability testing is best ordered and interpreted by a hematologist— this is because certain facets of hypercoagulability testing can be affected by drugs or clinical circumstances.49 Test results can be incorporated into current paradigms of individualized risk stratification and existing data, and an individualized plan for VTE prevention can be determined by the plastic surgeon, hematologist, and patient. Final Opportunity for Preoperative VTE Risk Modification In the preoperative setting, the surgeon’s decision to offer an elective operative procedure represents the final modifiable risk factor—preoperative consideration of VTE risk and the presence of modifiable risk factors (as opposed to non-modifiable factors, such as age, personal or family history of VTE, or genetic hypercoagulability) allows the surgeon to consider whether a patient’s VTE risk is too high to safely perform an elective procedure. INTRAOPERATIVE VTE RISK REDUCTION Anesthesia type represents a potentially modifiable intraoperative risk factor. Among the abdominoplasty population, Hafezi and colleagues50 have previously shown a significant decrease in postoperative pulmonary embolism using epidural as opposed to general anesthesia. This relationship was confirmed by pooling additional data51 in the American Association of Plastic Surgeons meta-analysis, in which non-general anesthesia was protective against Downloaded from https://academic.oup.com/asj/article-abstract/39/2/209/5017390 by guest on 20 February 2020 214 Aesthetic Surgery Journal 39(2) postoperative VTE, when compared to general anesthesia (OR 0.11, 95% CI 0.03-0.43).7 For certain procedures and certain patients, a general anesthetic may be unavoidable—thus, avoidance of general anesthesia is a modifiable VTE risk factor only for certain procedures, surgeons, and environments. Increased operative duration, as discussed above, is known to increase VTE risk.41 Preoperative consideration of the number of procedures to perform concurrently was discussed above,15,21 but maintenance of intraoperative efficiency is a second means to decrease operative time. Similarly, surgeons may choose to abort planned additional procedures if the initial planned procedures require more operative time than anticipated. Mechanical prophylaxis options include elastic compression stockings and intermittent pneumatic compression (IPC). General anesthesia, as well as anesthetics involving paralytics, can cause loss of calf muscle pump function and resultant venous
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