Incidence and characteristics of intravascular pulmonary migration of etonogestrel implants: A French nationwide study.

OBJECTIVE(S):To describe the features of etonogestrel implant (Nexplanon and Implanon) migration into the pulmonary vasculature and to estimate its incidence in France. STUDY DESIGN:We retrospectively reviewed French cases of implant migration into the pulmonary vasculature reported up to 2018. Patient clinical data were collected. The annual incidence of migration was estimated from the number of cases reported and number of implants sold. RESULTS:Twenty-seven cases of migration into the pulmonary vasculature were identified. In 19 cases (70%) it was stated that this was into the pulmonary artery (nine into the left branch, four into the right branch and six unspecified) and in the other eight cases (30%) it was it not specified whether this was into the pulmonary artery or one of its branches. The migration was discovered following a request for implant removal in 59% of cases, following respiratory complaints in 24%, and because the implant was no longer palpable in 17%. In the 24 cases for which information on removal (or not) was available, the implant was removed in 15 (60% by an endovascular procedure and 40% by invasive surgery); in the remainder it was left in situ. The incidence of migration into the pulmonary vasculature was 1.23 per 100,000 implants sold [95% CI 0.25-3.58] in 2014, increasing to 3.17 per 100,000 implants sold [1.37-6.24] in 2017. In 2016, the French National Agency for Medicines and Health Products Safety (ANSM) had recommended performing a systematic search for non-palpable implants, including at thorax level. CONCLUSIONS:The incidence of migration into the pulmonary vasculature is low. Nonetheless, because the consequences are potentially serious, in December 2019 the ANSM made recommendations to reduce this risk.