Aortic diameters at time of type A acute aortic dissection in genetically triggered versus non genetic aortopathies

Background and aims Aortic diameters may differ significantly across genetically triggered and non genetic aortopathies. This study aims to compare aortic diameters at the time of type A acute aortic dissection (TAAAD) in patients with bicuspid aortic valve (BAV), heritable thoracic aortic disease (HTAD) and non-BAV/non-HTAD. Methods Participants enrolled in the International Registry of Acute Aortic Dissection (IRAD) with aortic diameter measurements at presentation were considered. Among 7399 TAAAD patients, 266 had BAV [mean age 53.7 (±14.4) years old; 77% males], 199 had HTAD [mean age 40.2 (±14.1) years old; 57.8% males] and 6974 were non-BAV/non-HTAD [mean age 61.7 (±13.9) years old; 65.4 % males]. Comparisons were performed using Wilcoxon rank-sum, and Montecarlo or Mood’s median tests. Results HTAD patients were younger than BAV and non-BAV/non-HTA (p<0.001) patients. BAV root [median 4.8 cm (4.1-5.4)] and ascending aortic [median 5.5 cm (4.8-6.3)] diameters were larger than non-BAV/non-HTAD diameters [median 4.1 cm (3.6-4.7) and 4.9 cm (4.3-5.5), respectively; p<0.001 for both]. HTAD aortic root diameters [median 5.15 cm (4.2-6)] were similar to BAV (p=0.20) but larger than non-HTAD/non-BAV (p<0.001). HTAD and non-BAV/non-HTAD ascending aortic diameters were similar [median 4.8 (4-6.2) vs 4.9 (4.3-5.5), respectively; p= 0.86] but smaller than BAV [median 5.50 (4.80-6.30), p=0.02]. These results were consistent when aortic diameters were indexed to body surface area and height. Importantly, thoracic aortic aneurysm was recognized prior to TAAAD in a minority of patients, in particular less than 10% of the non-HTAD/non-BAV group. Conclusions At the time of TA-AAD, aortic diameters were larger in BAV than in non-BAV/non-HTAD patients, in all segments measured . This observation supports present guidelines suggesting that preventive aortic root surgery should not be performed earlier in BAV patients. Figure legend: Comparison between aortic diameters at the level of the aortic root and ascending aorta between the 3 groups. Q1, median, and Q3 are represented. P values intergroup are reported. HTAD: heritable thoracic aortic disease; BAV: bicuspid aortic valve.