Aortic Dissection in Genetically Mediated Aneurysms
What is the incidence, pattern, and relative risk for aortic dissection (AoD) among patients with genetically associated thoracic aortic aneurysm (TAA)?
The population comprised adult GenTAC (National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions)participants without AoD at baseline. Standardized core labs classified TAA etiology and measured aortic size. Follow-up was performed for AoD. Comparisons between groups with or without AoD were made using Student t-test (expressed as mean value ± standard deviation) or Mann-Whitney U test (median and interquartile range) as appropriate for continuous variables.
In the 1,991 GenTAC participants studied, bicuspid aortic valve (BAV; 39%) and Marfan syndrome (MFS; 22%) were leading diagnoses. AoD occurred in 1.6% over 3.6 ± 2.0 years; 61% occurred in MFS patients. Cumulative AoD incidence was sixfold higher among MFS patients (4.5%) versus others (0.7%; p < 0.001). MFS event rates were similarly elevated versus BAV patients (0.3%; p < 0.001). AoD originated in distal arch/descending aorta in 71%. 52% of affected patients, including 68% with MFS, had previously undergone aortic grafting. Among patients with proximal aortic surgery, distal aortic size (descending thoracic, abdominal aorta) was larger among patients with, versus those without, AoD (both p < 0.05), whereas ascending aorta size was similar. Conversely, among patients without prior surgery, aortic root size was greater among patients with subsequent AoD (p < 0.05), whereas distal aortic segments were of similar size. MFS (odds ratio, 7.42; 95% confidence interval, 3.43-16.82; p < 0.001) and maximal aortic size (1.86 per cm; 95% confidence interval, 1.26-2.67; p = 0.001) were independently associated with AoD. Only 4 of 31 (13%) AoD patients had predissection images fulfilling size criteria for prophylactic TAA surgery at subsequent AoD site.
The authors concluded that among patients with genetically associated TAA, MFS augments risk for AoD even after TAA grafting.
This study reports that patients with genetically associated TAA remain at risk for AoD in the current era. Furthermore, patients with genetically associated TAA are at risk for dissection even in the context of minimal aortic dilation, and that risk for dissection in native aortic segments persisted after prophylactic aortic grafting was performed. Additional research is indicated to determine whether novel imaging approaches and translational targets, such as genetic mutations or circulating biomarkers, may provide incremental utility to predict AoD among at-risk populations.
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