Reperfusion of Pulmonary Arteriovenous Malformations Treated by Catheter Embolization

<b>Objective:</b> The aim of this study was to evaluate patients with hereditary hemorrhagic telangiectasia (HHT) for the potential reperfusion of pulmonary arteriovenous malformations (PAVM) treated by catheter embolization using coils or embolization plugs and to analyze causes of possible reperfusion in order to further improve treatment. <b>Methods:</b> This retrospective study analyzed the data of 345 patients who underwent screening for pulmonary arteriovenous malformations in cases of suspected or confirmed HHT (Osler's disease). Of these, 118 patients with PAVM that underwent catheter embolization and had at least one follow-up study were included in our study and evaluated for potential reperfusion. Screening and follow-up for the detection of PAVM was performed by dynamic and high-resolution contrast-enhanced magnetic resonance angiography (MRA). The average follow-up time was 6.2 years. <b>Results:</b> Reperfusion was detected in 43 of 118 patients at follow-up. Thirty-five of these patients showed a recanalization of the treated vessel and in eleven patients the formation of collateral vessels resupplying the PAVM were identified as the cause of reperfusion. The average time between embolization and detected reperfusion was 5.6 years. The recanalization of both coils and plugs was observed. The recanalization of coils could be attributed in most cases to an insufficient packing density of the implanted coils. In addition, an enlarged diameter of the feeding artery was confirmed as a risk factor for reperfusion. <b>Conclusions:</b> As the reperfusion of embolized pulmonary arteriovenous malformations can occur after a long time interval post-treatment, regular lifelong follow-up studies after embolization are essential to detect reperfusion at an early stage and avoid serious complications like a brain abscess or stroke through prompt re-embolization. After coil embolization, attention should be paid to sufficiently dense packing to achieve adequate and permanent occlusion.