Acute type A aortic dissection is a life-threatening condition with evidence suggesting a role for environmental triggers, particularly cold exposure. However, the impact of subjective, or derived thermal stress, reflecting both ambient temperature and wind effects, on dissection incidence remains poorly characterized.

We conducted a retrospective, multicentre study including patients diagnosed with acute type A aortic dissection at 3 German tertiary medical centres from 1996 to 2016. For each patient, high-resolution meteorological data were retrieved from the nearest weather station for the 2 weeks preceding symptom onset. Distributed lag non-linear models, implemented within a case-crossover framework, were used to assess short-term associations between meteorological exposures and dissection odds.

Apparent temperature and windchill emerged as the most impactful weather variables. Lower apparent temperatures and higher windchill scores were associated with a pronounced and time-dependent elevation in the incidence of acute type A aortic dissection, peaking within 3-4 days prior to the event and attenuating thereafter. In contrast, in milder conditions and higher apparent temperatures, no increased incidence was seen. Additional weather factors such as elevated atmospheric pressure and low dew point were linked to increased odds, while lower humidity and minimal cloud cover appeared modestly protective.

Subjective cold exposure, as quantified by apparent temperature and windchill, may potentially be an acute trigger of acute type A aortic dissection. These findings highlight the importance of “felt” environmental conditions in risk assessment and point towards new avenues for prevention during adverse weather events.