Exploring Hypoattenuated Leaflet Thickening: Clinical Insights and Origins Post-Aortic Root and Arch Surgery with Biologically Valved Conduits

Background: Hypoattenuated leaflet thickening (HALT) is the thickening of aortic valve prosthesis leaflets, usually due to thrombotic formations, potentially leading to impaired valve function. While previously described in TAVI, origins and consequences remain elusive. This retrospective study assesses the incidence and correlations in patients undergoing aortic root replacement with valved composite grafts and arch repair.

Methods: Between 01/2015 and 12/2022, 519 patients at our center underwent aortic root replacement with biological valved conduits and arch repair requiring hypothermic circulatory arrest. All postoperative high-resolution computed tomography angiographies (CT-A) were analyzed by two members of the cardiac surgery department and one radiologist and correlated with follow-up visits. These included CT-A scans, echocardiographies, and systematic questioning about neurological events of possible embolic origin. Transient neurological events were defined as reversible deficits; loss of or double vision, loss of motor/sensory function, smell/taste or aphasia for <24 hours. Furthermore, impact of intraoperative hemostatic products, postoperative anticoagulation regimens, and transvalvular gradients was analyzed.

Results: Of the 519 patients, 49 (10%) expired during hospital stay and 98 (19%) were lost to follow-up. Thus, 372 patients were included. Among these, 60 (16%) had acute aortic dissection and 42 (8%) underwent reoperation. The follow-up period was 3.9 years (95% CI 3.05, 4.86). 105 (28%) patients showed clear signs of HALT with 44 (42%, p < 0.01), mostly visual, neurological episodes. The remaining 267 (72%) patients showed no abnormalities on CT-A. Among these, 9 (3%) transient neurological events were registered. Except for prothrombin complex concentrate (4,373 IU ± 2,089 IU versus 4,766 IU ± 1,659 IU, p < 0.01), there were no significant differences in the use of intraoperative hemostatic products, postoperative anticoagulation regimens, or transvalvular gradients between the groups.

Conclusion: HALT is a frequently observed phenomenon, with almost one in three patients following aortic root surgery presenting with thrombotic formations. Although no long-term implications were identified, neurologic events were significantly higher. While intraoperative hemostatic products did not provide definitive insights into the origins, it suggests that further research with extended follow-up periods and comprehensive diagnostic tools such as 3D echocardiography and MRI is warranted.

Publication History

Article published online:
11 February 2025