Reevaluating Thrombocytosis as a Risk Factor in Free Flap Surgery: Does Timing Matter?

Thrombocytosis, defined as a platelet count >400,000, has been implicated as a risk factor in free flap failure. Despite proposed mechanisms of pedicle thrombosis, recent studies have suggested that thrombocytosis has no effect on free tissue transfer viability. Risk factors that may compromise successful free tissue transfer should be understood and elucidated, with particular attention to thrombocytosis and its conflicting evidence in the literature. We hypothesize that thrombocytosis has no bearing on free flap success or the rates of pedicle thrombosis.

Our institution performed a retrospective chart review on all patients who underwent free flap reconstruction over the past 6 years. Patient demographics, medical history, type and location of free tissue transfer, preoperative platelets, postoperative platelets, and flap outcomes and complications (wound dehiscence, infection, hematoma, seroma, and need for blood transfusion) were recorded. Independent t test, Mann-Whitney U tests, χ2 test, and Fisher exact tests were used to determine P values to compare flap outcomes in patients with thrombocytosis (platelet count >400,000) and those with platelet counts less than 400,000.

In our 502-patient cohort, 71 were found to have a platelet count >400,000 (35 preoperatively and 36 postoperatively) and 431 patients had platelet counts <400,000. There were 42 reconstructive failures (flap success rate of 91.6%) and 111 returns to the operating room (OR). For patients with postoperative thrombocytosis, 24 flaps returned to the OR (44.4%), whereas in patients without thrombocytosis, 87 flaps returned to the OR (19.4%; P < 0.001). In patients with postoperative thrombocytosis, 10 OR returns were due to pedicle venous thrombosis (18.5%), in comparison to 10 returns for venous thrombosis in those with normal platelets (2.2%; P < 0.001). There was a small difference in free flap success rates between those with postoperative thrombocytosis and normal platelets, 88.7% versus 92.11%; however, this was not statistically significant ( P = 0.71). The thrombocytosis group had a higher incidence of overall postoperative complications ( P = 0.002).

Thrombocytosis has historically been cited as a risk factor for free flap reconstruction failure with recent conflicting evidence in the literature. In patients with postoperative thrombocytosis, we found an increased risk of venous thrombosis; however, this did not result in increased flap failure. There was an increase in postoperative complications, which corresponds with National Surgical Quality Improvement Program data reported in the literature. We suspect that thrombocytosis is not a harbinger of free flap failure but rather a marker for overall inflammation, which may confer a higher rate of venous thrombosis requiring reoperation and postoperative complications.