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Chen et al. Plast Aesthet Res 2023;10:24 https://dx.doi.org/10.20517/2347-9264.2022.136 Page 5 of 26

Combination Therapy
Although many recommendations for thromboprophylaxis have been proposed, there is no consensus on
any single regimen. Based on experience and literature review, Conrad et al. proposed a protocol consisting
of aspirin dosed 1.4 mg/kg/day administered pre- and postoperatively for 2 weeks, with intraoperative
heparin as a bolus and local topical agent . Stephan et al. and Brinkman et al. do not recommend aspirin
[58]
and instead adhere to heparin monotherapy [59,60] . Overall, current evidence seems to suggest that a more
conservative approach to prophylactic antithrombotics is warranted. In a recent systematic review, Liu et al.
concluded that postoperative antithrombotics including aspirin, dextran, and heparin had no significant
effects on flap thrombosis or flap failure, and may increase the risk for hematoma regardless of regimen .
[61]

At our institution, patients undergoing microsurgical breast reconstruction receive a bolus of heparin 5,000
2
units subcutaneously, or enoxaparin (40 mg or 0.5 mg/kg if BMI exceeds 40 kg/m ) subcutaneously
intraoperatively. Postoperatively, patients receive heparin 5000 units subcutaneously every 8 h, or
enoxaparin (same dosing scheme as previously stated) subcutaneously and aspirin 121.5 mg (half a baby
aspirin) once per day. In patients deemed at high risk for microvascular thrombosis, enoxaparin is
continued for 3-4 weeks postoperatively.

DIAGNOSIS
Intraoperative
Intraoperative assessment of anastomotic patency and detection of microvascular thrombosis allows for
rapid surgical correction and is imperative for flap survival. Historically, microsurgeons have relied on
clinical judgment and patency testing. This includes visual inspection of the flap for bleeding at the flap
edges, acoustic sonography over perforators, and examination of the vessel for visible or palpable pulsations
distal to the anastomosis. Patency can further be assessed with the Flicker test and Milking test .
[62]

If questions regarding flow remain after a simple inspection of the pedicle, more advanced techniques can
be used [63-65] . Fluorescent Indocyanine Green (ICG) angiography has since been shown to be a reliable,
sensitive, and ultimately cost-effective method for evaluating flap perfusion [64-66] . Specifically, the arterial
uptake phase in ICG angiography is highly sensitive and has been well-studied in the detection of arterial
thrombosis . The venous phase, and the data on its sensitivity, are less clear, and its interpretation is
[67]
oftentimes influenced by the experience of the surgeon . Yoshimatsu et al. report success using ICG
[68]
angiography to detect venous congestion and Sharaf et al. subsequently describe a “pathognomonic
heterogeneous or splotchy appearance” within the zone of ICG appearance that is characteristic of venous
congestion [Figure 1] [69,70] .

Flaps can also be interrogated intraoperatively using advanced flap monitoring techniques typically reserved
for the postoperative setting-including Near-Infrared Spectroscopy (NIRS) tissue oximetry (eg., ViOptix) or
technologies such as FLIR (Forward Looking Infrared) thermal imaging.

Postoperative
Flap monitoring techniques
It is well established in the literature that early detection of and intervention for microvascular thrombosis
maximizes the chance of flap salvage [71,72] . Therefore, having a reliable means of flap monitoring is critical. In
1975, Creech and Miller described the ideal flap monitoring technique as one that does not cause harm to
the patient or flap and is rapid, accurate, reliable, cost-effective, and applicable to all flap types . Jones
[73]
further proposed that the ideal monitor be objective, simple to use for inexperienced personnel, and capable
of continuous and prolonged monitoring . While no one flap monitoring technique embodies all of these
[74]