Aspirin Increases the Risk of Nondiagnostic Yield of Fine-Needle Aspiration and Biopsy of Thyroid Nodules

Abstract

Background: The link between the diagnostic yield of thyroid fine-needle aspiration and biopsy (FNAB) in patients taking antithrombotic or anticoagulant medications (AT/AC) remains poorly characterized. Objectives: We studied the risk of obtaining a nondiagnostic sample with ultrasound-guided thyroid FNAB in patients taking AT/AC medications. Methods: This is a retrospective cohort study using medical rec­ords of 556 patients who underwent thyroid FNAB. All cytology samples were reported using the Bethesda classification. For patients with a nondiagnostic cytology, logistic regression was used to calculate OR for patients taking AT/AC medications. Multivariate regression was used to adjust for potential confounding variables including age, cystic ultrasound features, presence of eggshell calcifications, number of passes performed, cystic aspirate on FNAB, and position of the nodule. Results: Out of 556 patients, cytology results were available for 547 patients. Of these, 46 subjects were taking aspirin and 1 was on warfarin. Among the entire cohort, 17.5% of the subjects had a nondiagnostic cytology. Among the patients on AT/AC medications, 34% had a nondiagnostic result compared to 16% for those not taking them (OR = 2.70, p = 0.003). The subgroup of patients taking aspirin had similarly higher odds of a nondiagnostic cytology (OR = 2.78, p = 0.002). These differences remained statistically significant after multivariate adjustment. Conclusions: This is the first study to demonstrate a 3-fold independently greater risk of a nondiagnostic FNAB cytology in patients taking aspirin. Our results highlight the importance of evaluating the need for continuation of aspirin in patients undergoing thyroid FNAB as this may impact the diagnostic yield of the procedure.

Adverse events unlikely after fine-needle aspiration biopsies of thyroid nodules in patients on low-dose aspirin: a prospective controlled systematic single center analysis

“…FNAB seem to be extremely rare, provided that recommendations for sterile organ puncture are followed [8,14,15]. Results of another fairly recent investigation suggest that the risk of non-diagnostic cytology increases 3-fold in patients taking ASA [16]. The cited non-diagnostic rate for untreated subjects (no ASA) was 16 %, compared with rates of 4 % and 8 % in our study subjects (ASA recipients and controls, respectively).…”

Effect of a stylet on specimen sampling in thyroid fine needle aspiration: A randomized, controlled, non-inferiority trial

“…A randomized design was used for the order of S+ first or S- first puncture of each nodule to exclude the effect of bleeding from the first puncture on the adequacy of the second specimen. Patients using anticoagulant therapy, such as aspirin and warfarin, were excluded since these treatments affect specimen adequacy ( 16 ). All possible interference factors were eliminated to ensure that other factors, except the stylet, do not affect the results.…”

Diagnostic quality of ultrasound‐guided fine‐needle aspirates samples from the canine liver and spleen is not significantly affected by using 22‐, 23‐, and 25‐gauge needles

“…Although FNA of patients with severe bleeding disorders or taking antithrombotic/anticoagulant medications appear to still be safe in humans, 17,18 a greater risk of nondiagnostic samples has been identified in human patients under antithrombotic drugs. 19 To standardize the sampling, the procedure was performed with no syringe attached to the needle.…”