The Impact of Lovenox Prophylaxis and Other Anticoagulants on Microvascular Free Flap Outcomes.

Objective: Microvascular free flap reconstruction for head and neck defects carries a 95% success rate. When flap compromise occurs, it is often due to vascular occlusion. This study seeks to determine what impact lovenox prophylaxis has on flap outcomes and postoperative complications.

Study design: A retrospective review.

Setting: A single tertiary institution.

Methods: A total of 1100 patients underwent microvascular free flap reconstruction from January 2010 to May 2019. The use of lovenox prophylaxis began in 2013, and by 2015, it was routinely used. Flap outcome and postoperative complications were compared between those who received postoperative lovenox prophylaxis and those who did not, using a chi-squared analysis. Outcomes among patients on therapeutic heparin and other oral anticoagulants were similarly examined.

Results: There was no difference between those with (n = 716) or without chemoprophylaxis (n = 384) in rates of flap compromise (11.46% vs 12.71%), salvage (43.19% vs 52.71%), and overall failure (6.51% vs 6.01%) (P = .45). Rates of arterial insufficiency (8.07% vs 7.82%, P = .89) and venous congestion (3.39% vs 5.73%, P= .09) were equivalent. Arterial insufficiency (23.85%, P = .0002) was highest among the therapeutic heparin group. The rate of hematoma was significantly different between those without chemoprophylaxis (2.08%), and those on lovenox (3.77%), heparin (10.55%), and other anticoagulants (14.55%) (P = 4 × 10^-8).

Conclusions: Lovenox prophylaxis does not appear to impact overall flap survival but does confer a small increase in hematoma risk. There were higher rates of complications among patients on therapeutic heparin. Patients who require anticoagulation for other medical comorbidities are nearly 4 times as likely to develop hematomas and should be counseled accordingly.