Body-surface adjusted aortic reference diameters for improved identification of patients with thoracic aortic aneurysms: Results from the population-based Heinz Nixdorf Recall study

IJCA-13519; doi:10.1016/j.ijcard.2011.05.039

-Hagen Kälsch, Nils Lehmann, Stefan Möhlenkamp, Anna Becker, Susanne Moebus, Axel Schmermund, Andreas Stang, Amir A. Mahabadi, Klaus Mann, Karl-Heinz Jöckel, Raimund Erbel, Holger Eggebrecht

Early identification of patients at risk for thoracic aortic aneurysm (TAA) has the potential of improving prognosis. So far, however, “normal” aortic dimensions are not well defined, rendering identification of patientswith enlarged aortas difficult. In the present study we aimed to (1) establish age- and gender-specific distribution of thoracic aortic diameters and (2) to determine the prevalence of asymptomatic TAA in a population-based European cohort.

kaelsch-aorta-diameter-2011-tab1aOf 4814 participants of the HNR study, 4609 (95.7%) ultimately had an EBCT scan performed between December 2000 and August 2003. The remaining were either unable to receive an EBCT (obesity, claustrophobia, etc.) or disclaimed the examination. Of the 4609 subjects with an EBCT scan, 4301 (93.3%) subjects had no history of known CAD. kaelsch-aorta-diameter-2011-tab1bOverall, ATA and DTA diameters were measured in 4129 (96%) of these 4301 individuals. Tables 1a and 1b show the demographics of the study population. The mean age of the participants was 59.4±7.8 years and 47% were males.

kaelsch-aorta-diameter-2011-tab2Overall aortic diameters were greater in ATA than in DTA, and were greater in men than in women. Table 2 shows the measurements of the thoracic aorta diameters in both genders. Aortic diameters were greater in men as compared to women in both the ATA (3.71±0.4 vs. 3.45±0.4 cm, pb0.0001) and DTA (2.82±0.3 vs. 2.54±0.3 cm, pb0.001) (Table 2).

kaelsch-aorta-diameter-2011-tab30.25 cm/m²) for 90th percentile, for 95th percentile (+0.225 vs. 0.25 cm/m²) and for 95th percentile (+0.275 vs. 0.225 cm/m²). Correspondingly, ATA and DTA increased (+0.2 vs. 0.225 cm/m²) for 90th percentile, for 95th percentile (+0.2 vs. 0.225 cm/m²) and for 95th percentile (+0.275 vs. 0.3 cm/m²) in women, respectively. Both genders were found to have an enlargement of ATA of 0.15 cm per 10 years, DTA increased 0.17 cm per 10 years in men and 0.16 cm per 10 years in women (Table 3).

kaelsch-aorta-diameter-2011-tab4Table 4 demonstrates the anthropometric and demographic measurements of participants above and below the 95th percentile for indexed ATA and DTA diameters. Overall, 213 participants revealed thoracic aortic diameters above this cut-off point (111 females/102 males). Mean body-surface adjusted aortic size diameters of males above the 95th percentile were 2.3±0.2 cm/m² for ATA and 2.1±0.3 cm/m² for DTA vs. 2.5±0.2 cm/m² for ATA and 2.3±0.3 cm/m² for DTA in females, respectively. Subjects above the 95th percentile had significantly higher blood pressures but lower indices of body size including body mass index and body-surface area.

kaelsch-aorta-diameter-2011-tab5Early and reliable identification of patients with dilated thoracic aortas before the onset of symptoms or complications has the potential for improving patient’s prognosis by allocation of intensified surveillance and early initiation of medical or elective surgical therapy. Distinguishing dilated from “normal” aortas is, however, difficult in the absence of well-defined reference values for thoracic aorta. Current studies are limited by sample size, non-contemporary imaging methodology used, and study population which may not be representative for the general population as they include stroke patients as well as patients referred for various cardiac and noncardiovascular CT indications [5–9,12–16] (Table 5). (weiter…)