Bicuspid aortic valve may affect aortic dimensions in aviators.

Abstract

Dear Editor: We read the article “ Cardiac indexes in young subjects with and without bicuspid aortic valve, ” written by Grossman et al., with great interest ( 1 ). They aimed to evaluate the effects of bicuspid aortic valve (BAV) on aortic and cardiac parameters in young healthy subjects with and without aortic regurgitation (AR). According to their study, although cardiac dimensions may be slightly increased in pilot applicants with BAV, the presence of AR of a mild-moderate degree does not infl uence aortic or cardiac indexes. They found a slight increase in systolic blood pressure in applicants with BAV and they also found an increase in aortic root diameter, left atrial diameter, left ventricular end systolic volume, interventricular septal thickness, and posterior wall thickness in those with BAV compared with those without BAV ( 1 ). These results are very important in researching the effects of BAV on cardiac structure in aviators during our daily practice. Thanks go to the authors for their contribution. But there are still few data about this subject. Carter et al. found no relationship between the aviation environment and aortic root diameter change ( 2 ). Although there were few pilots with BAV in their study, they found no signifi cant changes in the intraventricular septum width, left ventricular posterior wall width, or left ventricular performance. They found no incidents of sudden incapacitation or other medical event that jeopardized fl ight safety. We need a larger study concerning the effects of the aviation environment like exposure to G force on BAV and cardiac structure. In a recent study, Chen et al. concluded that high sustained positive acceleration had damaged mitochondrial ultrastructure, respiratory function, and antioxidant capacity at the cellular level in rats ( 3 ). In another study, Aparci et al. concluded that aortic dilation might be an occupational disease due to the nature of some professions (e.g., the military, security, weight lifters, athletes, heavy workers, etc.) and they emphasized earlier detection of aortic root dilatation and limitation of such strenuous activities in these individuals might be important for the prevention of future cases of aortic aneurysm and dissection ( 4 ). In a previous study, Grossman et al. (5) investigated the effect of acceleration forces on cardiac morphologic changes in jet fi ghter pilots. They concluded that exposure to acceleration forces in jet fi ghter pilots compared to low-performance aircraft pilots has not been found to signifi cantly affect cardiac and aortic indexes ( 5 ). In addition to these studies, we previously investigated longterm Valsalva and anti-G maneuvers and found they have no effects on aortic and cardiac morphologic and systolic functions, but do have effects on right ventricular diastolic function in aviators ( 6 , 7 ). In the present study (1), the authors concluded that similar preparticipation criteria for pilot applicants should be applied to subjects with BAV, regardless of the presence of mild-moderate AR. But we have some questions about this research. Was there any aortic coarctation or mild aortic stenosis in subjects with bicuspid aortic valve in this study? We know that aortic diameter may be increased in patients with bicuspid aortic valve with or without aortic insuffi ciency. Aortic velocity values would be useful to clarify this issue. Is there any relationship between aortic velocities and aortic dimensions? A comparison would be helpful according to the different periods, such as at the beginning of participation, after a certain number of fl ight hours, type of aircraft performance, and long-term exposure in pilots. We think that it is important due to long-term exposure to acceleration forces in pilot candidates with bicuspid aortic valve. Aortic stenosis, aortic dilatation, and ruptures are more likely with bicuspid aortic LETTER TO THE EDITOR