Registry of Aortic Diseases to Model Adverse Events and Progression (ROADMAP) in Uncomplicated Type B Aortic Dissection: Study Design and Rationale

Abstract

Purpose: To describe the design and methodological approach of a multicenter, retrospective study to externally validate a clinical and imaging-based model for predicting the risk of late adverse events in patients with initially uncomplicated type B aortic dissection (uTBAD).

Materials and methods: The Registry of Aortic Diseases to Model Adverse Events and Progression (ROADMAP) is a collaboration between 10 academic aortic centers in North America and Europe. Two centers have previously developed and internally validated a recently developed risk prediction model. Clinical and imaging data from eight ROADMAP centers will be used for external validation. Patients with uTBAD who survived the initial hospitalization between January 1, 2001, and December 31, 2013, with follow-up until 2020, will be retrospectively identified. Clinical and imaging data from the index hospitalization and all follow-up encounters will be collected at each center and transferred to the coordinating center for analysis. Baseline and follow-up CT scans will be evaluated by cardiovascular imaging experts using a standardized technique.

Results: The primary end point is the occurrence of late adverse events, defined as aneurysm formation (≥6 cm), rapid expansion of the aorta (≥1 cm/y), fatal or nonfatal aortic rupture, new refractory pain, uncontrollable hypertension, and organ or limb malperfusion. The previously derived multivariable model will be externally validated by using Cox proportional hazards regression modeling.

Conclusion: This study will show whether a recent clinical and imaging-based risk prediction model for patients with uTBAD can be generalized to a larger population, which is an important step toward individualized risk stratification and therapy.Keywords: CT Angiography, Vascular, Aorta, Dissection, Outcomes Analysis, Aortic Dissection, MRI, TEVAR© RSNA, 2022See also the commentary by Rajiah in this issue.

Keywords: Aorta; Aortic Dissection; CT Angiography; Dissection; MRI; Outcomes Analysis; TEVAR; Vascular.

Figure 1:

Study design. aa. = arteries, CTD = connective tissue disease, FL = false lumen, Max. = maximum, REDCap = Research Electronic Data Capture. (^⋆ = 250–300 patients in REDCap; # = 1000–1200 CT and MRI data sets in TeraRecon.)

Figure 2:

Baseline image analysis workflow. Overview of the five-step imaging workflow used at the Stanford core laboratory. In step 1, the aortic centerline (green line) is drawn at the center of the whole aorta (including true and false lumina) from the apical portion of the left ventricle (red line) to the aortic bifurcation (blue line). In step 2, the reader will evaluate the aortic cross-section with the maximum diameter to measure the aortic long and short axes (red lines). The aortic diameters will be obtained in a cross-sectional plane perpendicular to the aortic centerline. On the same cross-section, the reader will define the false lumen circumferential angle (step 3) by first measuring the true lumen circumferential angle between two arrows (red arrows) extending from the centerline to the aortic wall where the flap inserts into the aortic wall and then subtracting this result from 360°. In step 4, the reader will indicate the ostium (green contour) of the aortic branches, starting from the left subclavian artery, by using a cross-sectional plane perpendicular to the ostium of each vessel. Each aortic branch vessel will be categorized according to its connection to either the true lumen, the false lumen, or both the true and the false lumina. In the presence of accessory vessels (ie, accessory renal artery), only the vessel with major caliber will be considered. Finally, in step 5, the reader will label the intercostal arteries identifiable along the dissected aorta. AoMax = aortic maximal diameter, AoMin = aortic minimal diameter, SMA = superior mesenteric artery.