Chronic hypertension, medial degeneration, elastic fiber fragmentation, smooth muscle cell loss, and progressive aortic dilation are all mechanisms implicated in acute aortic dissection (AAD). Although cold weather does not create medial degeneration, it can precipitate issues in an already compromised aorta.
Population-level data consistently show winter peaks in acute aortic dissection and higher event rates on colder days. In fact, more granular analyses suggest that both absolute low temperatures and rapid temperature drops correlate with increased risk. The physiology is also plausible. For example, cold-induced vasoconstriction elevates afterload, and sympathetic activation increases heart rate and impulse along the aortic wall. Blood viscosity also increases in colder conditions, potentially further increasing vascular resistance. In patients with poorly controlled hypertension or pre-existing aortopathy, this combination increases the likelihood of intimal disruption and false lumen formation.
There’s also a circadian overlay interacting with the temperature. Early morning hours are associated with a surge in catecholamines and blood pressure. When cold exposure coincides with this physiologic surge, the additive increase in wall stress may be clinically relevant.
Here are some PubMed IDs to review the data: 39167531, 34849712, 34169738, 16147902, 27351414
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