Where is the Origin of the Last Normal Branch from Feeding Artery of Pulmonary Arteriovenous Malformations?

Abstract

PurposeReperfusion via pulmonary-to-pulmonary arterial anastomoses is known as one type of recurrence of pulmonary arteriovenous malformations (PAVMs) after embolization. It is important to occlude the fistulous portion beyond the origin of the last normal branch from feeding artery of PAVMs to prevent recurrence. In this study, we evaluate the origin of the last normal branch by CT as well as its visibility on pulmonary arteriography (PAG).Materials and MethodsWe reviewed forty patients with 77 PAVMs who underwent coil embolization between October 2007 and December 2017. All patients underwent MDCT before embolization. Axial and MPR CT lung images were reviewed with special interests in the origin of the last normal branch from feeding artery of PAVMs. The origin was classified into three portions, including sac, junction (portion just proximal to the sac) and proximal feeder (more than 5 mm proximal to the sac). We also evaluated whether PAG can depict the normal branches detected by MDCT.ResultsMDCT showed that the last normal branch originated from sac in 30 PAVMs (39.0%), junction in 39 (50.6%), and proximal feeder in 8 (10.4%).On selective PAG, the last normal branch could be visualized in 30 PAVMs (39.0%), although it could not be visualized due to high-flow shunt in the other 47 PAVMs.ConclusionsSelective PAG frequently fails to demonstrate the last normal branch from feeding artery of PAVMs, which often originates from the sac. Pretherapeutic evaluation of CT images of the last normal branch is important to prevent reperfusion of PAVMs.Level of EvidenceLevel 3, local non-random sample.

Effectiveness of Embolization for Pulmonary Arteriovenous Malformations from Distal of the Last Normal Branch of the Pulmonary Artery

“…Table 4 shows details of the coils used for PAVM embolization. The median (IQR) number, total length, and total volume of coils used were 11 (7)(8)(9)(10)(11)(12)(13)(14)(15), 255 (103-344) mm, and 315.3 (124.4-566.0) mm 3 , respectively. In the 13 cases wherein hydrogel-coated coils were used, the median (IQR) number of hydrogel-coated coils used was 4 (3-7).…”

“…Prevention of reperfusion is achieved by deploying embolization distal to the last normal branch of the pulmonary artery. An essential aspect of this procedure lies in the precise identification of the last normal branch using previous CT imaging, as selec-tive pulmonary angiography frequently fails to demonstrate the origin of the last normal branch [11]. In cases where the last normal pulmonary artery branch originates from the sac or junction, dense sac embolization is required.…”

“…In cases where the last normal pulmonary artery branch originates from the sac or junction, dense sac embolization is required. However, for cases wherein the last normal branch originates from the proximal feeder, some reports describe that extensive coil occlusion of the sac might not be necessary [5,11].…”

“…Before embolization, all patients underwent preembolization evaluation using multidetector computed tomography (MDCT) to assess the location, type of PAVM (simple/complex), location of the last normal branch of the pulmonary artery, and respective sizes of the feeding artery, sac, and draining vein. The origin of the last normal branch was categorized according to its location relative to the PAVM: the sac (originating within the sac), the junction (originating within 5 mm proximal to the sac), and the proximal feeder (originating more than 5 mm proximal to the sac), as previously described in the literature [11]. If a branch originated from the sac, we identified it as a pulmonary arterial branch based on the criteria that it is at an acute angle to the feeding artery compared to the draining vein and/or does not distribute to the territories of any adjacent pulmonary artery branches, as described in an earlier study [11].…”

“…Recanalization can result from factors such as insufficient packing or embolization of the feeding artery [7,10]. Moreover, to prevent pulmonary-topulmonary reperfusion, it is crucial to occlude the fistula distal to the origin of the last normal branch of the pulmonary artery [11]. Although there are reports that have described comparisons of feeding artery and sac embolization [10], no report has described an investigation of embolization locations distal to the origin of the last normal branch of the pulmonary artery.…”