How Compression Inside a Delivery System can Degrade the Cover of Aortic Endografts

Association Between Device Type and Type IIIb Endoleaks Following Thoracic Endovascular Aortic Repair

OBJECTIVE

Endoleaks following thoracic endovascular aortic repair (TEVAR) can lead to the need for re-intervention and aortic rupture. Given the recent recall of a specific thoracic stent graft type due to concerns about type IIIb endoleak (T3bE), in which blood leaks through the stent graft fabric, the aim was to characterise patterns of T3bEs among available TEVAR devices.

METHODS

Reports related to thoracic stent grafts in the Food and Drug Administration's (FDA) Manufacturer and User Facility Device Experience (MAUDE) database between 2010 and 2020 were reviewed. Proportional reporting ratios (PRRs) and chi squared tests were used to assess for the presence of a signal of association between device type and T3bE. A PRR > 2 and chi squared value > 4 with three or more reports overall constituted a signal of association. The institutional database of patients undergoing TEVAR for thoracic aneurysms since 2002 was also queried for T3bE.

RESULTS

There were 7 328 MAUDE reports available for analysis. When analysing T3bEs in the MAUDE database, the lowest PRR was 0.36 (95% confidence interval [CI] 0 - 1.03 in Gore CTAG, nine T3bE among 1 328 reports) and the highest was 2.07 (95% CI 1.72 - 2.42 in Medtronic Valiant, 64 T3bE among 2 520 reports). The T3bE chi squared value for Medtronic Valiant was 17.3. The relationship between Medtronic Valiant and T3bE was ascertainable by MAUDE data as early as 2013. Among 542 TEVARs for an aneurysm indication at Duke University Hospital since 2002, there were eight T3bEs - all in devices with sutured on graft material.

CONCLUSION

The Medtronic Valiant device met criteria for association with type IIIb endoleaks in the FDA's MAUDE database and met those criteria as early as 2013. A possible relationship between woven graft fabric and T3bEs is supported by the observation that all types of T3bE that occurred among a large number of TEVARs at the institution followed placement of grafts with sutured on woven fabric.

Fatigue of textiles used in vascular surgery: Application to carotid endarterectomy

Fatigue is a material-based phenomenon playing a significant role in the mechanical behavior of components and structures. Although fatigue has been well studied for traditional materials, such as metals, its underlying mechanisms are not thoroughly understood in novel applications such as the case of textiles used as patches to close the arteriotomy in carotid endarterectomy. The latter is a type of vascular surgery for the treatment of carotid artery disease in which after an arteriotomy and removal of atherosclerotic plaque closure is made with a patch sutured on the artery. Completion of the operation signals the initiation of complex mechanical and hemodynamic phenomena. Fatigue performance of the patch eventually determines the successful outcome of carotid endarterectomy. In this study, we evaluate with a two-fold approach the mechanics of patch angioplasty in carotid endarterectomy. First, an analytical model for the fatigue behavior of textiles is developed, considering the microstructure and geometry of the fabric. Then, the surgical procedure is simulated and a finite element analysis of the endarterectomized and patched carotid artery is employed. Stress fields are calculated, while deformation at the site of patch angioplasty indicates a potential cause for the formation of aneurismal degeneration after the surgery. Such analysis can provide a better understanding in the establishment of follow-up protocols.