Cardiac Surgery Resident McGill University Montréal, Quebec, Canada
Background: Current guidelines for surgical intervention in ascending aortic pathology aim to prevent acute type A aortic dissection (ATAD), yet 40% of ATADs present with diameters below recommended surgical thresholds. This study compared clinical and anatomical characteristics of patients surgically treated for ascending aortic aneurysm (ATAA) with those experiencing ATAD. We hypothesized that patients presenting with ATAD represent a distinct group compared to asymptomatic ATAA, indicating limitations of current diameter-based surgical criteria.
METHODS AND RESULTS: Methods - In this retrospective study, we enrolled 130 consecutive ATAD patients and 190 ATAA patients who underwent surgery according to established guidelines. Aortic diameters were measured by echocardiography and computed tomography scans. Analysis of the ATAA cohort identified 4 groups of aortopathies: 1) Bicuspid aortic valve (BAV), 2) older degenerative, 3) younger genetics, and 4) root dilatation with aortic insufficiency (AI). ATAD patients were then manually assigned to these groups for comparative analysis.
Results - Age (62.23±12.1 vs 62.48±13.4 years), gender distribution (68.5% vs 73.7% male), and hypertension prevalence (66.5% vs 56.32%) were similar between ATAD and ATAA cohorts. Notably, 56.9% of ATAD patients had maximal aortic diameters under 50 mm at the root, ascending aorta, and arch levels. Compared to ATAA patients, ATAD patients exhibited significantly smaller aortic root diameters (39.1±7.3 vs 44.1±8.8 mm; p< 0.0001), larger aortic arches (35.4±8.3 vs 31.8±6.3 mm; p=0.0043), and similar ascending aortic diameters (49.8±9.2 vs 48.9±7.7 mm; p>0.9999). Regarding group assignment, ATAD patients were less likely to have BAV (1.5% vs 34.5%; p< 0.0001). Moreover, 29.2% of ATAD patients remained unclassified, characterized by significantly smaller roots (35.6±3.5 mm; p< 0.0001) and larger arches (34.8±4.5 mm; p< 0.05) compared to ATAA patients.
Conclusion: ATAD patients demonstrate distinct anatomical features and aortopathy profiles compared to asymptomatic ATAA patients, highlighting limitations in current size-based surgical criteria. A significant proportion of ATAD cases do not align with established ATAA groups, suggesting unique pathophysiological mechanisms. Therefore, improved risk stratification beyond simple aortic diameter measurement is necessary for optimal surgical decision-making.
