In-Hospital Mortality of Patients With Acute Type A Aortic Dissection Hospitalized on Weekends Versus Weekdays

BACKGROUND: In acute aortic dissection, weekend admissions are reported to be associated with increased mortality compared with weekday admissions. OBJECTIVE: This study aimed to determine whether patients with acute type A aortic dissection (ATAAD) admitted on weekends had higher in-hospital mortality than those admitted on weekdays in the Tokyo metropolitan area, where we developed a patient-transfer system for aortic dissection. METHODS: Data were collected during the first year after our transfer system began (cohort I) and in the subsequent years from 2013 to 2015 (cohort II). RESULTS: We studied 2,339 patients (500 in cohort I; 1,839 in cohort II) with ATAAD. Patients with weekend admissions had higher in-hospital mortality than those with weekday admissions in cohort I. In association with increased interfacility transfer during weekends and reduced mortality at non–high-volume centers, the in-hospital mortality in the weekend group improved from 37.2% in cohort I to 22.2% in cohort II (P < 0.001). After inverse probability weighting adjustment, weekend admission was associated with higher in-hospital mortality in cohort I (odds ratio: 2.28; 95% confidence interval: 1.48 to 3.52; P < 0.001), but not in cohort II (odds ratio: 0.96; 95% confidence interval: 0.75 to 1.22; P = 0.731). On multivariable analyses, weekend admission was associated with higher in-hospital mortality in combined cohort I+II; the associations between weekend admission and mortality were not significant in cohort II. CONCLUSIONS: We found a significant reduction in in-hospital mortality in patients with weekend admissions for ATAAD. No mortality difference between weekend and weekday admissions was observed in the later years of the study.