Objectives To evaluate the association of onset season with clinical outcome in type A acute aortic dissection (AAD).
Design A single-centre, observational retrospective study.
Setting The study was conducted in Fuwai Hospital, the National Centre for Cardiovascular Disease, Beijing, China.
Participants From 2008 to 2010, a set of consecutive patients with type A AAD, confirmed by CT scanning, were enrolled and divided into four groups according to onset season: winter (December, January and February), spring (March, April and May), summer (June, July and August) and autumn (September, October and November). The primary end points were in-hospital death and all-cause mortality during follow-up.
Results Of the 492 cases in this study, 129 occurred in winter (26.2%), 147 in spring (29.9%), 92 in summer (18.7%), and 124 in autumn (25.2%). After a median follow-up of 20.4 months (IQR 9.7–38.9), the in-hospital mortality in cases occurring in autumn was higher than in the other three seasons (23.4% vs 8.4%, p<0.01). Long-term mortality was comparable among the four seasonal groups (p=0.63). After adjustment for age, gender and other risk factors, onset in autumn was still an independent factor associated with increased risk of in-hospital mortality (HR 2.05; 95% CI 1.15 to 3.64, p=0.02) in addition to surgical treatment. Further analysis showed that the seasonal effect on in-hospital mortality (autumn vs other seasons: 57.4% vs 27.3%, p<0.01) was only significant in patients who did not receive surgical treatment. No seasonal effect on long-term clinical outcomes was found in this cohort.
Conclusions Onset in autumn may be a factor that increases the risk of in-hospital death from type A AAD, especially in patients who receive conservative treatment. Immediate surgery improves the short-term and long-term outcomes regardless of onset season.
- acute aortic dissection
- onset seasons
- in-hospital death
- Stanford type A
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Contributors ZC, XF and YY participated in the study design. ZC and BH performed the data analysis. HL, ZZ, ZL, SZ and RH helped with patient data collection and follow-up. The first draft of the manuscript was written by ZC and XF. All authors interpreted the results, revised the report, commented on the manuscript and approved the final version.
Funding This work was supported by two grants (grant numbers 81570430 and 81441017) from the National Natural Science Foundation of China to XF.
Competing interests None declared.
Patient consent Obtained.
Ethics approval Study protocols were approved by the appropriate institutional review boards of Fuwai Hospital and complied with the Declaration of Helsinki.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No additional data are available.
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