Persistence in Coil-Embolized Pulmonary Arteriovenous Malformations with Feeding Artery Diameters of 3 mm or Less: A Retrospective Single-Center Observational Study.

PURPOSE: To assess persistence in coil-embolized pulmonary arteriovenous malformations (PAVMs) with feeding artery diameters ≤ 3 mm.

MATERIALS AND METHODS: Fifty-eight patients (21 male, 37 female; mean age, 43 y; range, 13-71 y) with 141 simple-type PAVMs treated from 2004 to 2014 were analyzed retrospectively. Inclusion criteria were one or more PAVMs with feeding artery diameters ≤ 3 mm ("small PAVMs"), treatment with coil embolization, and presence of a follow-up chest computed tomographic (CT) angiogram at approximately 6 months. Feeding artery diameter, total coil length, and coil nest-to-PAVM sac distance were measured on arteriographic images. Coil packing density was estimated. Persistence was defined as less than 70% reduction in PAVM sac size and was assessed for each PAVM with respect to previous arteriogram or CT angiogram. Each variable was statistically tested for association with persistence.

RESULTS: On follow-up CT arteriography, 111 of 141 PAVMs (79%) showed a 70% or greater reduction in size of the sac and were deemed not persistent. The remaining 30 (21%) with unchanged or minimally reduced sac sizes were classified as persistent. Feeding artery diameter, coil size, quantity of coils, shape of coils, coil nest length, compaction, and visible packing density did not affect persistence, but coil nest-to-sac distance was directly correlated with persistence (P < .006). This result held true even with nest-to-sac distances of less than 1 cm.

CONCLUSIONS: Small PAVMs have a high persistence rate after coil embolotherapy. Most previously described risk factors for PAVM persistence do not seem to apply to these PAVMs, with the exception of coil nest-to-sac distance.