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Purpose: Management of acute type A aortic dissection (AAAD) is challenging and operative strategies are varied. We used the STS Adult Cardiac Surgery Database (STS ACSD) to describe contemporary surgical strategies and outcomes for AAAD. Results: In this cohort, median age was 60 years old, 66% were male, and 80% had hypertension. The most common arterial cannulation strategies included femoral (36%), axillary (27%), and direct aortic (19%). The median perfusion and cross-clamp times were 181 and 102 min, respectively. The lowest temperature on bypass showed significant variation. Hypothermic circulatory arrest (HCA) was used in 78% of cases.Among those undergoing HCA, brain protection strategies included antegrade cerebral perfusion (31%), retrograde cerebral perfusion (25%), both (4%), and none (40%). Median HCA plus cerebral perfusion time was 40 min. Major complications included prolonged ventilation (53%), reoperation (19%), renal failure (18%), permanent stroke (11%), and paralysis (3%). Operative mortality was 17%. The median intensive care unit and hospital length of stays were 4.7 and 9.0 days, respectively. Among 640 centers, the median number of cases performed during the study period was three. Resuscitation, unresponsive state, cardiogenic shock, inotrope use, age >70, diabetes, and female sex were found to be independent predictors of mortality. Conclusions:These data describe contemporary patient characteristics, operative strategies, and outcomes for AAAD in North America. Mortality and morbidity for AAAD remain high.

Gold-standard diagnosis of Alzheimer’s disease (AD) relies on histopathological staging systems. Using the topographical information from [18F]MK6240 tau positron-emission tomography (PET), we applied the Braak tau staging system to 324 living individuals. We used PET-based Braak stage to model the trajectories of amyloid-β, phosphorylated tau (pTau) in cerebrospinal fluid (pTau181, pTau217, pTau231 and pTau235) and plasma (pTau181 and pTau231), neurodegeneration and cognitive symptoms. We identified nonlinear AD biomarker trajectories corresponding to the spatial extent of tau-PET, with modest biomarker changes detectable by Braak stage II and significant changes occurring at stages III–IV, followed by plateaus. Early Braak stages were associated with isolated memory impairment, whereas Braak stages V–VI were incompatible with normal cognition. In 159 individuals with follow-up tau-PET, progression beyond stage III took place uniquely in the presence of amyloid-β positivity. Our findings support PET-based Braak staging as a framework to model the natural history of AD and monitor AD severity in living humans.

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