Risk factor analysis for aortic dissection after aortic valve replacement in patients with tricuspid aortic valve.

OBJECTIVE: Aortic dilatation concurrent with aortic valve disease is a common condition. However, the incidence of aortic dissection after aortic valve replacement for tricuspid aortic valve has not been fully investigated. Therefore, we performed a risk factor analysis for the incidence of aortic dissection after aortic valve replacement in patients with tricuspid aortic valve. METHODS: We retrospectively reviewed 599 patients who underwent aortic valve replacement at our hospital between January 2000 and December 2020. We performed a risk factor analysis for the incidence of aortic dissection after aortic valve replacement in patients with tricuspid aortic valve. RESULTS: Seven patients developed late aortic dissections during the follow-up period. All patients with aortic dissection underwent aortic valve replacement for aortic regurgitation. Multivariable analysis revealed that aortic regurgitation was an independent predictor of aortic dissection (p < 0.0001). The mean ascending aortic diameter at aortic valve replacement for aortic regurgitation was significantly greater in patients with aortic dissection than in those without aortic dissection (46 [43.5-46] mm vs. 39 [36-42] mm, p < 0.001). The predictive cutoff value of ascending aortic diameter was indicated using receiver operating characteristic curve analysis; 46.0 mm (area under the curve: 0.8987). Freedom rates from aortic dissection in patients with aortic regurgitation and an ascending aortic diameter ≥ 46 mm were significantly lower than those in patients with an ascending aortic diameter < 46 mm (66.7% vs. 100% at 5 years, p < 0.0001). CONCLUSION: Aortic regurgitation combined with ascending aortic dilatation at aortic valve replacement could be a significant risk factor for late aortic dissection.

A rapid aneurysmal formation after late open conversion of endovascular abdominal aortic repair with complete endograft explant.

Late open conversion (LOC) after endovascular aneurysm repair (EVAR) is associated with high morbidity and mortality. Standard surgical technique of LOC has not been established. This report presents a rapid aneurysmal formation in the unreplaced infrarenal aorta after LOC with complete endograft explantation without suprarenal fixations. A 76-year-old man presented with a left common iliac artery aneurysm (CIAA), for which he underwent EVAR to embolize the left internal iliac artery. Although his aneurysmal sac size initially showed a reduction, computed tomography at the 3-year interval post-EVAR demonstrated an increased sac size. Thus, he underwent open aortic repair of the CIAA. Though the postoperative course was uneventful, the size of the unreplaced infrarenal aorta showed a significant increase one year after open conversion. Reoperation was performed, but vascular prosthesis infection occurred as a complication and the patient died on the 196th postoperative day.

A Novel Design Approach for Self-Crack-Healing Structural Ceramics with 3D Networks of Healing Activator.

Self-crack-healing by oxidation of a pre-incorporated healing agent is an essential property of high-temperature structural ceramics for components with stringent safety requirements, such as turbine blades in aircraft engines. Here, we report a new approach for a self-healing design containing a 3D network of a healing activator, based on insight gained by clarifying the healing mechanism. We demonstrate that addition of a small amount of an activator, typically doped MnO localised on the fracture path, selected by appropriate thermodynamic calculation significantly accelerates healing by >6,000 times and significantly lowers the required reaction temperature. The activator on the fracture path exhibits rapid fracture-gap filling by generation of mobile supercooled melts, thus enabling efficient oxygen delivery to the healing agent. Furthermore, the activator promotes crystallisation of the melts and forms a mechanically strong healing oxide. We also clarified that the healing mechanism could be divided to the initial oxidation and additional two stages. Based on bone healing, we here named these stages as inflammation, repair, and remodelling stages, respectively. Our design strategy can be applied to develop new lightweight, self-healing ceramics suitable for use in high- or low-pressure turbine blades in aircraft engines.