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Inchauste. Plast Aesthet Res 2023;10:27 https://dx.doi.org/10.20517/2347-9264.2022.139 Page 9 of 15

Figure 4. Left breast DIEP flap venous congestion seen on post operative. Please change to left breast DIEP flap with venous congeston
on post operative day 2. DIEP: deep inferior epigastric perforator.

Medications to prevent and treat thrombus have been given to patients for decades. One of the oldest and
[47]
most widely used anticoagulants is heparin . McLean discovered heparin in 1916, but its clinical inception
was not until 1935 . Heparin activates antithrombin III which inhibits thrombin, thus preventing
[47]
conversion of fibrinogen to fibrin and inhibiting clot propagation. Heparin aids in the migration of
endothelial cells while increasing negative charge, disturbs the fibrin lattice, and prevents platelet
[16]
binding . Heparin is an effective treatment for both arterial and venous thrombosis.
Heparin can be used locally as an irrigation solution or given to the patient as a systemic anticoagulant
during microsurgery. Most microsurgeons use a heparinized saline solution at concentrations of 100 unit/
[48]
mL as a local irrigation solution during microvascular anastomosis . The heparinized saline solution as an
irrigation solution during microvascular anastomosis has shown lower rates of thrombus formation
compared to saline and lactated ringers. It provides high concentrations of heparin locally to the site of
microvascular anastomosis to prevent thrombus formation without systemic anticoagulation effect. It can
be used liberally during the primary anastomosis, during any anastomotic revision, or at the time of take
back since the systemic absorption is minimal.

Numerous intraoperative and postoperative protocols with the use of pharmacologic anticoagulants exist in
the literature, but there is no consensus on an ideal protocol. Systemic heparin given as a bolus at the time
of microvascular anastomosis was routine in early microsurgery history. The studies report a range of doses
from a flat 5,000 units up to 160 units/kg [46,49] . Although systemic heparin did not significantly increase flap
survival or decrease thrombus formation, it did increase the risk of flap hematoma . More recently,
[48]
systemic heparin has not been given routinely but is reserved for patients with a history of thromboembolic
events or in patients with extensive thrombosis at the time of flap salvage. Operative intervention for
thrombectomy is the standard and systemic anticoagulation can be used to supplement flap salvage but does
not replace operative exploration.

Dextran is a polysaccharide that is a product of fermentation with a molecular weight of 40 or 70. Dextran
40, a low molecular weight dextran, is a non-protein colloid given intravenously to expand plasma volume,
cause hemodilution, and impair platelet function . Dextran 40 was used for venous thrombosis
[50]
prophylaxis and was typically given as 50-100 g the day of surgery and then a fixed dose of 500 mL daily for
2-5 days postoperatively in autologous free flap breast reconstructions infancy [50-52] . Later studies