Acute type A aortic dissection (ATAAD) is a surgical emergency associated with high mortality. While patient-related risk factors are well-established, beliefs persist regarding the influence of lunar phases, meteorological conditions, and astrological signs on disease occurrence and outcomes.

We retrospectively analysed all patients who underwent emergency surgery for ATAAD at Bordeaux University Hospital between 1996 and 2020. The primary objective was to assess the association between environmental factors (lunar phases, atmospheric pressure, temperature, and astrological signs) and ATAAD incidence. Secondary objectives included assessing their association with 30-day mortality and postoperative morbidity (intensive care unit length of stay, extracorporeal membrane oxygenation use, and mesenteric infarction). Meteorological data were available for 603 patients from 2010 onward.

Among 920 patients (70% male; mean age 63 ± 13 years), the 30-day mortality rate was 9.7%. Lunar phases were not associated with ATAAD incidence (first quarter 26%, last quarter 25%, new moon 25%, full moon 24%; p = 0.91), mortality, or complications. Atmospheric pressure showed no association with ATAAD occurrence or outcomes. Temperature showed a weak correlation with ATAAD incidence (r = 0.11, p = 0.01), but not with mortality. Astrological signs were not associated with ATAAD incidence, mortality, or morbidity. Longer cardiopulmonary bypass duration (odds ratio [OR] = 0.994 per minute; p = 0.01) and diabetes (OR = 4.63; p = 0.01) were associated with 30-day mortality.

Environmental factors were not associated with ATAAD incidence or outcomes. Established clinical factors remain the primary determinants of mortality.