LAUSR

Stroke is the Achilles’ heel of thoracic endovascular aortic repair (TEVAR). The incidence of stroke increases when TEVAR is performed more proximally, in the aortic arch, compared with the descending thoracic aorta. The most common pathways that result in stroke during TEVAR are (1) dislodgment of particulate debris from atherosclerotic lesions in the aortic wall during positioning and deployment and (2) air embolization. In the August 2019 issue of the JEVT, Makaloski et al reported on the latter phenomenon, analyzing the distribution of air bubbles in the supra-aortic arteries during endograft deployment. Using an idealized in vitro setup, the authors found that a significant amount of air is released in the supra-aortic arteries during endograft deployment. Previous studies showed that proximal landing zone angulation and the resulting hemodynamic forces in zones 2 and 3 change with increased aortic arch angulation (arch types I-III). Following these findings, we hypothesize that the geometry of the non-patient-specific glass model of a type I aortic arch can influence the distribution of air emboli over the supra-aortic arteries. Still, we believe it is safe to conclude from the experiments of Makaloski and colleagues that air emboli are released in the supra-aortic branches when TEVAR is performed in proximal landing zones 2 and 3. Furthermore, these results agree with the findings of Bismuth et al, who detected microembolic signals during endograft deployment using transcranial Doppler (Figure 1). The clinical significance of these air bubbles is unclear; still, one can imagine that it would be beneficial to eliminate all gaseous bubbles from the cerebral circulation. Makaloski et al are not the first to raise the topic of air embolization during endograft deployment after regular flushing of the endograft and sheath. Nonetheless, medical device manufacturers have not developed a solution to eliminate all gas from the devices prior to TEVAR. To limit the impact of gaseous bubbles in the cerebral circulation, additional carbon dioxide flushing of the endograft and sheath prior to insertion has been proposed, as carbon 852924 JETXXX10.1177/1526602819852924Journal of Endovascular Therapyvan Bakel et al article-commentary2019