Temporal Analysis of Intraoperative Arterial Thrombosis: Validation of a 20-Min Patency Check

BACKGROUND: Although most arterial thromboses occur within the first postoperative day, the precise timing of intraoperative arterial thrombosis remains poorly defined. We aimed to evaluate the accuracy of the 20-min patency check routinely performed at our institution and determine the optimal timing to detect intraoperative arterial thrombosis. METHODS: A retrospective analysis was conducted of patients who underwent microscopic arterial anastomosis between 2021 and 2025. The primary outcome was the diagnostic accuracy of the 20-min patency check. Secondary outcomes included the optimal timing for detecting intraoperative arterial thrombosis and patient-related factors associated with its occurrence. RESULTS: Among the 454 arterial anastomoses performed in 438 patients, intraoperative arterial thrombosis occurred in 41 anastomoses (9.0%), corresponding to 9.4% of patients. Thrombosis occurred in non-breast reconstructions, including 10.8% in head and neck reconstructions, whereas no cases were observed in breast reconstructions. Among the 41 thrombosis cases, 78% were detected within 20 min after anastomoses completion. The sensitivity and specificity of the 20-min patency check were 78% and 98%, respectively. Receiver operating characteristic analysis suggested a statistical threshold of 57 min for detecting intraoperative arterial thrombosis (sensitivity, 93%; specificity, 94%). No patient-related factors associated with an increased risk of intraoperative arterial thrombosis were identified. CONCLUSIONS: The 20-min patency check is effective for detecting intraoperative arterial thrombosis particularly in non-breast reconstructions. To further improve sensitivity, an additional assessment before wound closure may help identify thrombosis that developed after the initial check.