Intravasation complicating hysterosalpingo-foam sonography (HyFoSy) using ExEm® Foam

Background: Transvaginal hysterosalpingo-foam sonography (HyFoSy) assesses tubal patency in an outpatient setting and without ionising radiation, unlike traditional hysterosalpingography (HSG) under fluoroscopy. Like HSG, HyFoSy may be complicated by uterine intramural contrast leak, leading to venous intravasation. Intravasation of particulate contrast agents risks pulmonary or cerebral emboli. Aims: We aimed to assess the intravasation rate of HyFoSy using ExEm((R)) Foam and association with endometrial thickness, ExEm((R)) Foam volume, uterine length, adenomyosis severity, uterine morphology or pain score. Methods: An ethics-approved retrospective study on all HyFoSy examinations between 23 January 2018 and 27 October 2021 on sub-fertile patients, trying to conceive. Initial transvaginal sonography confirmed anatomy, uterine morphology, adenomyosis severity and endometrial thickness. Subspecialist radiologists performed HyFoSy with sonographer assistance. Intravasation was identified in real time but also checked for afterwards. Patients were asked to rate instillation pain/discomfort from one to ten immediately afterward. Results: Four hundred and thirty-six (n = 436) patients met inclusion criteria. Thirty (6.9%) experienced intravasation. Endometrial thickness and pain score were associated with intravasation. For every millimetre increase in endometrial thickness, the odds of intravasation decreased by 26% (P = 0.010). For every point increase on the pain scale, the odds of intravasation increased by 22% (P = 0.032). There was no evidence of an association between instilled ExEm((R)) Foam volume or the other previously published parameters with intravasation. Conclusion: A 6.9% rate of intravasation was observed. Both endometrial thickness and pain score were significantly associated with intravasation. There was no evidence of an association between ExEm((R)) Foam volume and intravasation.