Circadian variations in the onset of aortic dissection in northern China.

This study explored the periodic changes in the onset of aortic dissection in a single center in northern China, with the goal to improve predictability and prevention. We collected the clinical data of 1121 patients from Hebei Province treated for acute aortic dissection at Fuwai Hospital between January 2010 and December 2016. The patterns of aortic dissection during different periods of each day, each month, and each quarter of a year were analyzed. Variations in the number of cases were summarized for weekdays, weekends, and different periods of a day in each season. We compared the differences in gender, age, body mass index, Marfan syndrome, hypertension, and the type of aortic dissection during different time periods and different seasons. In the study, 774 patients (69.1%) with type A aortic dissection and 347 patients (30.9%) with type B aortic dissection were included. The average age of 1121 patients was 51.4 ± 12.0 years. Overall, the peak period for the onset of aortic dissection in a day was between 13:00 and 18:00. There was no statistically significant difference in the number of cases between weekdays and weekend (P = 0.94). Most cases occurred in winter (30.9%); the rate of onset was the lowest in summer (16.6%). No statistically significant difference was observed between male and female patients in terms of variations during different periods of a day (P = 0.45) and seasons (P = 0.12). In conclusion, aortic dissection displayed circadian and seasonal patterns in northern China. Onset of the disease peaked between 13:00 and 18:00 in a day. Winter was the peak season for the onset of acute aortic dissection, regardless of sex, type of dissection and age.