Anatomical Factors Predictive of Type B Intramural Hematoma Evolution

The circulating volume and maximum aortic diameter of an aortic dissection at 1 month may be predictive of outcomes of type B intramural hematomas, according to a study published in the Annals of Vascular Surgery.

Researchers sought to identify patients at risk for unfavorable anatomical evolution of intramural hematomas based on anatomical criteria and aortic volume analysis, with the aim of proposing early treatment to promote aortic remodeling in those patients.

A total of 25 patients (mean age at diagnosis, 68 years; 56% women; 84% with hypertension) treated at the Timone Hospital in Marseille, France for a type B intramural hematoma of the descending thoracic aorta between 2009 and 2018 were included in the study. An initial computed tomography analysis indicated that 10 of the patients (40%) presented with anatomical variations of the supra-aortic trunks. In this cohort, 8 patients (32%) had ≥1 supra-aortic trunks arising from the hematoma, 15 patients (60%) had ≥1 visceral artery born from the hematoma, 8 patients (32%) presented with or had been treated for aortic aneurysm, and 2 patients (8%) presented with an aneurysm of the aortic isthmus upstream of the hematoma.

The results of a short-term anatomical evolution of the hematomas indicated significant growth of the diameter of the circulating lumen, and a significant decrease in the longitudinal extension and hematoma thickness at the aortic diameter level.

At 18 months follow-up, 13 and 12 patients had favorable and unfavorable anatomical evolution, respectively. Eleven of the unfavorable evolutions were treated with a covered stent graft. Overall, 70% of patients were treated in either the acute or subacute phase, and 4 patients were treated in the chronic phase. Eight patients (72%) required a supra-aortic trunk debranching.

A significant increase in maximum aortic diameter was identified in patients in the unfavorable evolution group. Patients in both the favorable and unfavorable evolution groups had significant increases in the diameter of the circulating lumen. Hematoma extension decreased in both groups, and this reduction was more important in patients with a favorable evolution of the hematoma. These patients also had a significant decrease in hematoma thickness, hematoma volume, and total aortic volume.

Factors including male gender, type of pain, and time of occurrence of the intramural hematoma were identified as poor prognostic factors in a comparative anatomical study. The following anatomical factors were found to contribute to poor prognosis: maximum aortic diameter, maximum circulating lumen diameter, number of intimal ulcerations, and aortic diameter at the level of intimal ulceration at 1 month of follow-up.

Study limitations include its retrospective nature and the small number of participants, due to the rarity of intramural hematomas.

“These prognostic factors were identified at the early stage…and could allow interventional treatment in the acute or subacute phase in order to promote an optimal aortic remodeling,” noted the study authors. “The progression of the maximum aortic diameter and of the circulating volume after 1 month of follow-up could be predictive factors of the poor long-term evolution of type B intramural hematomas.”

References

Bolomey S, Blanchard A, Barral P-A, et al. Is the natural anatomical evolution of type B intramural hematomas reliable to identify the patients at risk of aneurysmal progression? [published online January 2, 2020]. Ann Vasc Surg. doi: 10.1016/j.avsg.2019.11.048