Author + information
- Catherine Meuleman, MD,
- Franck Boccara, MD,
- Stephane Ederhy, MD,
- Ghislaine Dufaitre, MD,
- Bernard Fleury, MD and
- Ariel Cohen, MD, PhD* ()
- ↵*Hopital Saint Antoine, Cardiology, 184 rue du faubourg Saint Antoine, Paris, 75571, France
In a recent issue of the Journal, Serizawa et al. (1) reported that thoracic aortic size was significantly greater in patients with obstructive sleep apnea (OSA) syndrome than in those without OSA syndrome. Whether OSA impacts aortic root size has not been yet fully investigated. We recently assessed thoracic aortic size in an observational single group of 76 consecutive patients with documented OSA (mean age 52.7 ± 9.5 years, 70 men [92%], apnea-hypopnea index 56.5/h) referred in our institution between March 2005 and March 2007 (2). Of note, 51% had hypertension. The aortic root diameter was measured by transthoracic echocardiography (TTE) at sinuses of Valsalva level, in the parasternal long-axis view, at end-diastole, according to Roman's recommendations (3). We found that mean aortic root diameter was 35.3 ± 3.8 mm (range 26.9 to 44.6 mm), as compared with 36.8 ± 3.6 mm in the study of Serizawa et al. (1). Aortic root diameter was significantly associated with age and male sex but not with arterial hypertension, in agreement with Serizawa et al. (1). In contrast, we did not find any correlation between aortic root diameter and OSA's characteristics (apnea-hypopnea index, time spent with oxygen desaturation <90%, Epworth Sleepiness Scale score, or treatment with continuous positive airway pressure). In addition, we did not find any correlation between carotid-femoral pulse wave velocity (aortic stiffness) and aortic root diameter.
We would like to draw attention to the different mean body mass index in the 2 populations studied (24.7 ± 3.1 kg/m2in the study of Serizawa et al.  in Japanese patients vs. 31.5 ± 5.8 kg/m2in the French population studied). Determinants of thoracic aortic size are still a matter of debate; however, age, weight, height, and body surface area are considered the main determinants of aortic dilation (3,4). However, in our study including obese OSA patients, body mass index did not influence aortic root size. As depicted in Roman's normograms (3), aortic root size should be indexed to body surface area and age when using TTE. Another difference with the study of Serizawa et al. (1) is the method of measurement of thoracic aortic size: TTE in our study while computed tomography was used in their group of patients (1). However, the agreement for ascending aortic diameter measured by echocardiography and computed tomography has been evaluated to be as high as 95% (5).
Finally, using Roman's normograms and TTE in our study, we did not find a high proportion of aortic dilation reported when aortic root diameter at the sinus of Valsalva level was considered as mean values >2 SDs above the regression line (3.9%). In the near future, additional trials should be performed to confirm the observation that a greater aortic root size is associated with OSA and, if confirmed, to examine its determinants and underlying mechanisms. There is also a need for evaluating the impact of OSA therapy with continuous positive airway pressure on heart geometry including aortic root size and ventricular function in large clinical trials.
- American College of Cardiology Foundation