Contributory factors to hemorrhage after ultrasound-guided fine needle aspiration of thyroid nodules with an emphasis on patients taking antithrombotic or anticoagulant medications

Background: Thyroid nodules are a common clinical problem and ultrasound-guided fine needle aspiration (US-FNA) biopsy is widely used for evaluation of thyroid nodules. However, few studies have addressed the contributing factors to hemorrhage after US-FNA of thyroid nodules. Objectives: To assess the contributory factors related to patient characteristics, ultrasound (US) features of the thyroid nodules, and the US-FNA procedures to affect hemorrhage complications after US-FNA of thyroid nodules. Patients and Methods: Between March 2014 and April 2015, 366 consecutive patients who underwent US-FNA of thyroid nodules were enrolled in this retrospective study. The characteristics of hematomas, including the location, maximum size, and clinical course, were assessed. The relationships between hematomas and factors related to the medical characteristics of patients, US characteristics of the nodules, and FNA procedural factors were analyzed. Results: Data on 365 nodules in 321 patients who underwent US-FNA of thyroid nodules were analyzed. Minor hemorrhagic complications developed in 14 (3.8%) of the 365 nodules. There were no statistically significant differences between patients taking or not taking an anticoagulant or antithrombotic (P = 0.270). Factors related to increased risk of hematoma were male sex (P = 0.031), larger maximum size (P = 0.002), a cystic or predominantly cystic nodule (P < 0.0001), a probable benign nodule (P < 0.0001), thicker needle size (P < 0.0001), and a greater number of the needle passes (P = 0.005). Conclusion: US-FNA can be performed safely even in patients taking anticoagulant or antithrombotic agents. Factors related to hemorrhagic complications are male sex, larger nodules, cystic or predominantly cystic nodules, probably benign nodules, thicker needles and a greater number of needle passes.