Temporal analysis of intraoperative arterial thrombosis: Validation of a 20-min patency check

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.

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.

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.

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.