Effects of atmospheric pressure dynamics on abdominal aortic aneurysm rupture onset

Background: The effect of atmospheric pressure (AP) on the onset of abdominal aorta aneurysm rupture (RAAA) remains an unanswered question. We have investigated the seasonal variation and the effect of AP dynamics on RAAA by analysing the largest series of intraoperatively confirmed RAAA. Patients and methods: To realize this study we have performed a retrospective analysis of 546 patients with RAAA, operated within 503 days at the Clinic for vascular and endovascular surgery CCS between 1.1.2003 and 31.12.2012. AP data for Belgrade city were obtained from meteorological yearbooks published by the Republic Hydrometeorological Service of Serbia measured at the hydrometeorological station "Belgrade Observatory". Only patients with a residence within the extended Belgrade region, exposed to the similar AP values, were included in the analysis of the AP effect on RAAA. Results: RAAA were observed more frequently during winter and autumn months but without significant difference in comparison to other seasons. Months with higher AP values were associated with a higher RAAA rate (p = 0.0008, R2 = 0.665). A similar trend was observed for the monthly AP variability (p = 0.0311, R2 = 0.374). Average AP values did not differ between days with and without RAAA. However, during the three and seven days periods preceding RAAA AP variability parameters were greater and AP was rising. Conclusions: Although these pressure differences are very small, higher AP values over longer periods of time as well as greater variability are associated with RAAA. The exact mechanism behind this association remains unclear. The postulation that low AP may precipitate RAAA based on the Laplace law should be discarded.