Activated Clotting Time-Guided Systemic Heparinization as One Component of a Stepwise Salvage Algorithm for...

The internal mammary vessels are commonly used as recipient vessels for free flap breast reconstruction. However, inadequate arterial flow may be encountered intraoperatively. This hypothesis-generating study evaluated the safety and feasibility of activated clotting time (ACT)-guided systemic heparinization as one component of a salvage strategy in such situations.

We retrospectively reviewed consecutive autologous breast reconstructions using the internal mammary artery (IMA) between 2019 and 2025. Based on intraoperative jet bleeding status and intimal findings, IMA vessels were categorized into three groups: normal flow, inadequate flow managed by conventional measures, and inadequate flow subsequently managed by ACT-guided systemic heparinization. ACT-guided systemic heparinization targeted an ACT of 200 s. An initial heparin bolus infusion of 36-60 IU/kg was given, followed by ACT measurement 15-30 min later and every 30-60 min thereafter, with additional heparin administered for ACT ≤ 200 s. Clinical outcomes were evaluated and compared.

A total of 103 IMA vessels (101 patients) were analyzed: 80 (77.7%) in the normal flow group, 17 (16.5%) in the inadequate flow group, and 6 (5.8%) in the ACT-guided heparinization group. Patient characteristics, aortic calcification, IMA diameter, and blood loss did not differ among groups (all p > 0.05). Postoperative hematoma rate was 2/80 for normal flow, 0/17 for inadequate flow, and 0/6 for ACT-guided heparinization (p > 0.05). Median peak ACT was 238 s, and median intraoperative heparin dose was 4758 IU. Despite the significantly longer intraoperative flap ischemia time in the ACT-guided heparinization group (normal flow: 98.5 min, inadequate flow: 127 min, ACT-guided heparinization: 208 min; p < 0.01), all six flaps survived.

As part of intraoperative rescue, ACT-guided systemic heparinization was employed successfully in 5.8% of IMA vessels in this series. ACT monitoring provides rapid and objective assessment and may represent an additional intraoperative option for suboptimal arterial flow.