eComment: Meteorological conditions and acute cardiovascular events; is there any correlation? Free

We read with great interest the recent report by Dr. Benouaich and colleagues and we would like to congratulate them for their interesting results [1]. We think also that the study of Dr. Benouaich et al. offers useful information on this topic and we would like to comment on this article. The authors’ aim was to study the correlations between weather conditions and the occurrence of type A acute aortic dissections (AAD); the most common catastrophic disease of the aorta.

Many authors have studied the impact of the temperature on the cardiovascular system (coronary arteries, aorta, bioprosthetic heart valve hemorrhage/thrombosis, etc.), because they are of the opinion that events are more frequent in certain seasons. Bhaskaran et al. who have studied the influence of the meteorological conditions on the coronary arteries suggested that both hot and cold weather had detrimental effects on the risk of myocardial infarction. However, further studies are necessary to determine the magnitude of these effects and to demonstrate which patients are vulnerable [2]. Not well known is the pathogenetic mechanism through which the temperature and the weather in general affect the cardiovascular system. Thrombogenicity of blood is known to have seasonal variations.

Narang et al. [3]conducted a study on the hemorrhage or thrombosis in patients with mechanical heart valves in various seasons. They found that the number of patients with prolonged international normalized ratio (INR) and the incidence of hemorrhagic events peaked in hottest months of the year. The number of patients with rapid clotting and the incidence of embolic events peaked in coldest seasons of the year. They found also a significant correlation between temperature and thrombogenicity in patients with prosthetic heart valves on long-term anticoagulation [3].

Other authors [4] investigated whether presentation of AAD has seasonal variations. The frequency of AAD was found to be significantly higher during winter vs. other seasons. A relatively high positive correlation was found between the incidence of AAD and the mean atmospheric pressure [4], while another study conducted in the UK for six years found no correlation between temperature or atmospheric pressure and the incidence of AAD [5].

In our opinion, the abrupt changes of the temperature and atmospheric pressure or the extreme cold or hot conditions have an impact on the vessels wall and on the blood viscosity. New, documented studies are needed to determine the precise mechanism of seasonal variation on the cardiovascular system.

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