Onset seasons and clinical outcomes in patients with Stanford type A acute aortic dissection: an observational retrospective study

Abstract

ObjectivesTo evaluate the association of onset season with clinical outcome in type A acute aortic dissection (AAD).DesignA single-centre, observational retrospective study.SettingThe study was conducted in Fuwai Hospital, the National Centre for Cardiovascular Disease, Beijing, China.ParticipantsFrom 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.ResultsOf 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.ConclusionsOnset 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.

Effect of Weather Conditions on the Occurrence and In-hospital Mortality of Stanford Type A Acute Aortic Dissection

“…Previous studies investigated whether the onset season acted as a trigger in the prognostic value of patients with AAD; however, no effect of seasonal variability could be found on the patients' outcome and in-hospital mortality (15,28). In our study, we also did not observe any effect of seasonality on in-hospital mortality, which is different from a study conducted in Beijing, located in northern China (29). This inconsistency may be explained by the different seasonal patterns in Beijing and Fujian.…”

Effects of seasonal and climate variations on in-hospital mortality and length of stay in patients with type A aortic dissection

“…In China, the weather becomes cool and humid in autumn due to frequent rainfalls and the atmospheric pressure (AP) fluctuates intensely [24]. The reduction in temperature and fluctuation in AP may lead to increased sympathetic activity, resulting in increased vasoconstriction or vasospasm and higher blood pressure consequently [25]. Also, the fluctuation of AP may increase the risk of rupture of the abdominal aortic aneurysm [26,27].…”

Effect of Season and Climate on in-hospital Mortality and Length of Stay for Patients With Type A Aortic Dissection

“…21 The drop in temperature and uctuation in AP may lead to increased sympathetic activity, causing more severe vasoconstriction or vasospasm, higher blood pressure. 22 Some studies have con rmed that the uctuation of AP might increase the risk of rupture in abdominal aortic aneurysm. 23,24 In the same way, drastic uctuations of systolic blood pressure result from increased alteration of AP in autumn can cause greater risk of postoperative residual dissection rupture, leading to statistically signi cant higher in-hospital mortality rate in our study.…”