Aortic stenosis is a risk factor for all-cause mortality in patients on dialysis: a multicenter prospective cohort analysis

Background: Aortic stenosis (AS) is common in patients on dialysis as well as in the general population. AS leads to difficulty with dialysis therapy because of unstable conditions such as intradialytic hypotension due to low cardiac output. However, the precise morbidity rates and risk factors of AS in patients on dialysis are unknown. Moreover, there are no large-scale observational studies regarding the association between AS in patients on dialysis and mortality. Therefore, we will investigate whether morbidity of AS in patients on dialysis is associated with mortality. Methods: This is a multicenter prospective cohort analysis in the Tokai region of Japan. The 75 participating centers in this study will enroll approximately 2400 patients during 12 months, with or without AS. We started enrollment in July 2017 and will follow patents until June 2023. Transthoracic echocardiography will be performed to evaluate aortic valve. Parameters used for evaluation of aortic valve are mean pressure gradient between left ventricle and ascending aorta, aortic valve area, and maximum aortic jet velocity. We will diagnose AS using the criteria based on the 2014 American Heart Association/American College of Cardiology Guideline. We will also perform transthoracic echocardiography at 12, 24, 36, 48, and 60 months. Survival prognosis and CV events will be determined at the end of June 2019, 2020, 2021, 2022, and 2023. Development of AS will be also evaluated as new onset or annual change in AS parameters. We will classify patients based on the presence or absence of AS and the stages of AS and will compare outcomes. Study outcomes will include the following: 1) all-cause mortality rates; 2) incidence of cardiovascular (CV) events; 3) CV-related mortality rates; 4) infection-related mortality rates; 5) new onset or development of AS. Discussion: We will consider the following hypotheses in this study, among others: The prevalence of AS is higher in dialysis patients; new onset and development of AS are associated with factors that are specific for dialysis, such as hyperphosphatemia, hyperparathyroidism, and medication; and outcomes in AS patients are poorer than in patients without AS at baseline.