Risk Factors of Incomplete Thrombosis in the False Lumen After Endovascular Treatment of Extensive Acute Type B Aortic Dissection

Study Questions:

What are the risk factors for incomplete thrombosis of the false lumen following thoracic endovascular aortic repair (TEVAR) in subjects with extensive acute type B aortic dissections?

Methods:

This retrospective study evaluated 124 individuals at two sites with acute type B aortic dissection undergoing TEVAR, and examined potential risk factors for incomplete thrombosis of the false lumen that included patient demographics, procedure characteristics, and anatomic features. Inclusion criteria included dissection extending below the celiac artery, completely patent false lumen at intervention, and complete baseline and follow-up computed tomographic imaging.

Results:

On follow-up imaging at a mean of 53 ± 9 months, the false lumen was completely patent, partially thrombosed, and completely thrombosed in 12, 88, and 24 patients, respectively. There were no significant differences between groups with different false lumen status by age, gender, or comorbidities, and there were no differences in procedural details including operating time, length covered, vessel bypass, or visceral branch stenting. Significant differences in false lumen status were observed between groups for anatomic characteristics including the number of re-entry tears, the number of visceral branches from the false lumen, and the maximal diameter of the false lumen (p < 0.001 for each). On multivariable analysis, independent risk factors for incomplete thrombosis of the false lumen included maximal diameter of false lumen (odds ratio [OR], 1.3; p = 0.004), re-entry tears (OR, 30.7; p < 0.001), and visceral branches arising partially or completely from the false lumen (OR, 10.1; p < 0.001).

Conclusions:

Patients undergoing TEVAR for extensive acute type B dissection are more likely to have incomplete thrombosis of the false lumen in the presence of a large false lumen, re-entry tears, and visceral branches arising partially or completely from the false lumen.

Perspective:

Incomplete false lumen thrombosis following TEVAR for acute extensive type B aortic dissection has been associated with an increased risk of mortality and adverse events. Prior literature has reported a large variation in false lumen thrombosis after TEVAR, and the present study finds that only 19% of individuals with an extensive dissection had complete thrombosis of the false lumen. It makes sense that the presence of re-entry tears and visceral branches involving the false lumen are associated with a lack of complete thrombosis, as these serve as potential channels for continued blood flow. This study identifies potential risk factors for incomplete false lumen thrombosis, which is reported as a risk factor for adverse events in prior literature. Until more data are available, it may be reasonable to follow patients with these risk factors more closely with surveillance imaging.

Clinical Topics: Cardiac Surgery, Vascular Medicine, Aortic Surgery

Keywords: Aortic Aneurysm, Thoracic, Thrombosis, Risk Factors


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