Retrograde type A aortic dissection during or after thoracic endovascular aortic repair: a single center 16-year experience.

Objective: This article aims to investigate the incidence rate of retrograde type A aortic dissection (RTAD) and the risk factors of RTAD in relation to thoracic endovascular aortic repair (TEVAR). Methods: Patients with thoracic aortic disease who underwent TEVAR at Henan Provincial People's Hospital from January 2004 to December 2019 were enrolled in the present research. The risk factors associated with RTAD following TEVAR using univariate and multiple logistic regression analyses. Results: During the study period, A total of 1,688 TEVAR patients were included in this study, and of these, 1,592 cases were included in the type B aortic dissection (TBAD) group, and 96 cases were included in the non-TBAD group. There were 1,230 cases of aortic dissection and 362 cases of aortic intramural hematoma and/or penetrating ulcer in the TBAD group. The non-TBAD group included 68 cases of thoracic aortic aneurysm, 21 cases of thoracic aortic pseudoaneurysm, and seven cases of congenital aortic coarctation. The overall incidence rate of RTAD was 1.1% (18/1,688) in patients, all of which occurred in the TBAD group. The cohort comprised 18 RTAD patients with an average age of 56.78, consisting of 13 males and 5 females. Among them, 13 individuals exhibited hypertension. Ten instances happened within the TEVAR perioperative period, including two cases during the surgery, six cases occurred within three months, two cases occurred after one year, and the longest interval was 72 months following TEVAR. TEVAR was successfully implemented in 17 patients, while the operation technique was temporarily altered in one case. The new entry position for RTAD was identified as the proximal region of the stent graft (SG) in 13 patients, while in five cases, the entry site was more than 2 cm away from the proximal region of the SG. 17 cases were at the greater curvature of the aorta, and one case was at the lesser curvature. Multivariate logistic regression analysis revealed that the SG oversizing ratio is a relevant risk factor for RTAD. However, ascending aortic diameter, aortic arch type, SG type, and anchored region were not directly related to the occurrence of RTAD. Conclusion: RTAD is a rare yet catastrophic complication. It could occur both during the procedure, early and late postoperative periods. Maintaining an appropriate SG oversizing ratio is crucial to minimize the risk of RTAD.

Subclavian steal syndrome decreases neurogenesis in the cerebellar cortex and affects cognitive function in rabbits.

Subclavian steal syndrome (SSS) is a condition characterized by a steno-occlusive impairment of the proximal subclavian artery. The majority of patients with SSS are asymptomatic, while symptomatic patients present with neurological symptoms. SSS is a risk factor for cerebral ischemia, which reacts badly upon cognitive function; however, it remains unknown whether SSS is able to cause progressive cognitive impairment. In the present study, the potential effects of SSS on cognitive function were investigated using atherosclerotic rabbits as a model of SSS. A total of 48 male New Zealand rabbits were divided into the control, sham and SSS groups. The results of eyeblink experiments indicated no significant differences among the three groups; however, SSS did appear to exert a negative impact on neurogenesis in the cerebellar cortex. In order to further clarify the mechanisms underlying this SSS-mediated reduction in cell proliferation, the energy metabolism, immune function and oxidative stress statuses were evaluated by determining the levels of adenosine triphosphate (ATP), adenosine, interleukin (IL)-1ß, IL-6, malondialdehyde, 8-hydroxy-2'-deoxyguanosine, CuZn-superoxide dismutase and catalase. The results showed that the levels of extracellular ATP in the cerebellar cortex had decreased, while levels of adenosine had also decreased. These findings suggest that SSS is able to inhibit neurogenesis in the cerebellar cortex by decreasing the extracellular ATP levels. Furthermore, these changes may result in an impairment of the cognition of the rabbits. The early diagnosis and treatment of SSS may, therefore, prevent or mitigate cognitive impairment in the future.