Association Between Aortic Calcification and Primary Intimal Tear in Type B Aortic Dissection.

BACKGROUND

This study aimed to determine the associations between aortic calcification distribution and primary intimal tears (PITs) in patients with acute type B aortic dissection (TBAD) and evaluate the role of calcifications in PIT formation using computational fluid dynamics (CFD).

METHODS

We included 2 cohorts: 163 acute TBAD patients retrospectively enrolled from our center (cohort 1) and 97 acute TBAD patients from a clinical trial (cohort 2). First, we cross-sectionally analyzed and compared the epidemiology of CT-visible calcification distribution at PIT sites across both cohorts. Second, fluorine-18 sodium fluoride positron emission tomography/computed tomography (18F-NaF PET/CT) was used to detect CT-invisible microcalcifications near the PIT regions. Third, CFD modeling simulated predissection and postdissection hemodynamic environments around calcifications, analyzing wall shear stress (WSS) and oscillatory shear index (OSI).

RESULTS

Among the combined 260 patients, calcifications adjacent to PITs were observed in 18.5% of cases, predominantly Type I calcifications located along dissected intimal flaps. Comparison between the cohorts revealed no significant differences in this distribution pattern. In 2 exploratory PET/CT cases, we observed focal increases in 18F-NaF uptake near PIT-associated regions, suggesting local microcalcification activity. CFD simulations performed in a single case identified hemodynamic abnormalities (low WSS and high OSI) near calcifications that spatially overlapped the eventual PIT.

CONCLUSION

A significant spatial association exists between calcifications and PITs in aortic dissection, with intimal tears preferentially forming at calcification edges. The PET/CT and CFD observations offer preliminary mechanistic support, suggesting that microcalcification activity and local hemodynamic disturbances may co-localize with PIT; however, these findings are exploratory and require validation in larger studies.