Decrease of Environmental Temperature May Trigger the Onset of Acute Aortic Dissection

Aim: The most important risk factors for a Stanford type A acute aortic dissection (AAD) include arterial hypertension and connective tissue disorders, while numerous studies have identified meteorology factors, such as environmental temperature also play an important role. The aim of this study is to explore the relationship between environmental temperature and the frequency of AAD surgically threated over a 12-year period at a Croatian university hospital. Methods: This is a retrospective, monocenter observational study conducted at the University Hospital Centre Zagreb. The study includes 134 patients who were threated surgically for Stanford type A AAD between January 2001 and December 2012. Temperature categories (low, moderate and high) were based on the calculated monthly average environmental temperature and standard deviation given from official daily environmental temperatures for the respective period. Results: The results show a higher frequency of AAD in days of low temperature compared to days of moderate temperature or high temperature. The frequency of days with AAD was somewhat higher in moderate than high temperature category, but the difference is not statistically significant. The relative frequency of AAD for low, moderate and high temperature categories were 4.55, 2.96 and 1.93, respectively. Conclusion: Environmental temperature drop induces stressful adaptive body response, including an additional hemodynamic load and increase in arterial blood pressure, strong enough to trigger the AAD-etiopathogenesis. Furthermore, our findings indicate that body response to environmental heat may differ from a response to reduced environmental temperature, due to observed small number of events in days of high temperature.