Hematoma Risk After Needle Electromyography in Patients Using Newer Oral Anticoagulants

To assess the safety of needle electromyography in patients on non-vitamin K oral anticoagulants (NOACs) compared with warfarin.

A retrospective chart review was done in patients who underwent needle electromyography studies while they were using warfarin and NOACs. After the needle electromyography, all the patients were monitored for 2 hours and ultrasound of high-risk muscle groups was done. The complications were classified based on the International Society on Thrombosis and Hemostasis definitions.

Fifty-eight patients were included: 29 were using NOACs and the other 29 were on warfarin. The mean age was 59.33 ± 16 years. Hemorrhagic complications from needle electromyography were noted in 9 patients: 7 (77.7%) NOACs and 2 (22.3%) warfarin. Among them, 6 patients (66.6%) met the diagnostic criteria for Clinically Relevant Non-Major Bleeding criteria proposed by International Society on Thrombosis and Hemostasis and 3 patients (33.4%) had an asymptomatic hematoma on ultrasound evaluation. A total of 267 muscles were tested and only 9 (3.3%) muscles had hemorrhagic complications. One patient (rivaroxaban) had acute bleeding requiring pressure bandage, five patients (two apixaban, two rivaroxaban, and one warfarin) had clinical hematoma that required ice packs, and three patients (two rivaroxaban and one warfarin) had a hematoma on ultrasound of deep muscles.

Patients on NOACs had minimal risk of clinically relevant hemorrhagic complications, and the risk is not significantly different from those on warfarin.