eComment: Influence of meteorological conditions on the onset of acute type A aortic dissection Free

The report of Benouaich et al. [1] highlights the factors responsible for the onset of acute aortic dissections (AAD). The pathogenesis of AAD is a result of the interplay of three factors: a predisposition provided by an abnormality or weakening of the aortic media, an agent of intimal injury or tear resulting in the intimomedial flap, and hemodynamic factors that propagate the dissection once it has been initiated.

Predisposing factors must be differentiated from precipitating factors of AAD [2]. Precipitating factors act on the basis of a transient hypertensive reaction to trigger the onset of AAD in the predisposed aorta. From the report of Benouaich et al.[1], a relative decrease in environmental temperature is clearly a precipitating factor of AAD.

Another significant point in their study deserves attention. The mean age of the patients studied was 62.5±11.7 years. It is the opinion of this author that age is significant in this context as meteorological conditions induce a more pronounced effect on the cardiovascular system of the aged than the young. Hess and colleagues [3] studied the pressor responses to superficial skin cooling in young (25 years old) and elderly (65 years old) subjects. They found that superficial skin cooling elicited an increase in blood pressure from resting levels (P<0.05) in both groups. However, the magnitude of this pressor response (systolic and mean blood pressure) was more than two-fold higher in older adults (P>0.05 vs. younger adults). The aortic pulse wave velocity, a measure of central arterial stiffness obtained before cooling, was found to be the best predictor of the increased pressor response to superficial skin cooling in older adults. Older adults are therefore more susceptible to the influence of the meteorological changes on the onset of AAD.

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