Gender-related differences in aortic diameters: why do we use the same cutoff?

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Patient’s body size and gender are major determinants of aortic dimensions. Even though female gender is associated with smaller aortic dimensions, surgery indication for thoracic aorta aneurysms is still based mainly on absolute diameters without considering gender. Therefore, if 4 cm is the number which allows us to discriminate aortic dilation in women is still controversial. Objective to compare the upper limit of normal (ULN) and Z score between genders in the population of the MATEAR Study (prospective nationwide multicenter registry in Argentina) and to determine the usefulness and fairness of the guideline’s recommendations about aortic diameters in women. Methods It was a prospective nationwide registry (53 centers). We included 1,000 healthy adult individuals (mean age: 38.3±12.7 years) being 553 women (56.7% Caucasian, 38.3% Native Americans). Echocardiograms were performed in all patients measuring aortic dimensions at 6 levels following the current standard recommendations: aortic annulus, aortic sinuses, sinotubular junction (STJ), proximal ascending aorta, aortic arch, and proximal descending aorta. Absolute diameters and indexed diameters by body surface area and height were compared between men and women, as well as the estimated ULN in order to analyze discrepancies of the recommended ULN (4cm) in female individuals. Results Table 1 shows the baseline characteristics of the study population by gender. The mean age was similar in both sexes (39.1±13.4 years in women and 37.2±12.3 years in men). Women had lower values in all anthropometric parameters, they were 13 cm shorter than men, and had lower left ventricular diameters, ventricular mass, septal thickness and medium blood pressure. The aortic measures at the six levels revealed that women had lower absolute aortic diameters in all aortic segments. However, when the indexed parameters were analyzed in the aortic root and STJ, women presented lower height indexed diameters but higher BSA/indexed diameters (Table 2 and Figure 1). Regarding the Z score evaluation, we found that the recommended ULN (4 cm) was higher in women than men, with a Z score equivalent to 3.61 and 2.34 respectively. Moreover, in our registry 3.62 cm was the ULN in women which corresponded to a Z score of 2.5. Conclusions As was suggested in previous studies aortic diameter indexed by height or BSA appear to be the most appropriate measurements for considering aortic dilatation. In our registry, women showed lower absolute aortic diameters in all segments placing the recommended ULN of 4cm as a misguided value for considering aortic dilatation in women. Therefore, gender should always be taken into account when defining aortic dilatation.