Outflow Through Aortic Side Branches Drives False Lumen Patency in Type B Aortic Dissection

Figures

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  Figure 1. 3D segmentation of three representative baseline Computed-tomography (CT)-scans. Black arrows indicate intimal tears. The false lumen (FL) is non-patent along its entire length (A). Non-patent FL in the proximal segment, partially patent FL at the level of major visceral branches, fully patent FL in the distal segment (B). Fully patent FL along its entire length (C). Minor branches originate from the FL in fully patent segments of the FL, while they originate from the TL in non-patent segments of the FL (A). In partially patent FL (B) minor branches originate from the FL in the patent segment and from the TL in the non-patent segment.

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  Figure 2. Correlation between the axial length of the patent false lumen (FL) (x-axis) and the number and size of intimal tears, the distance from the left subclavian artery (LSA) to the most proximal intimal tear (distance from LSA), the relative FL area, and the number of major and minor side branches arising from the FL (y-axis). Spearman's rank correlation was applied and the corresponding p-value is displayed for each scatter-plot.

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  Figure 3. Forest-plot of standardized beta values in a multiple regression model for the axial length of the patent false lumen (FL) (left) and the non-patent FL (right) at baseline. The dependent variables are the number and size of the intimal tears, the distance from the first intimal tear to the left subclavian artery (LSA) (distance to LSA), the relative FL area, the number of major and minor side branches arising from the FL, and the number of minor side branches arising from the true lumen (TL). Standardized by division of two standard deviations. *p ≤ 0.05; **p ≤ 0.01, ***p ≤ 0.001. The resulting multiple linear regression model predicted the length of the patent FL with good accuracy (R2 = 0.77), while the prediction was somewhat lower for the non-patent FL (R2 = 0.47).

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  Figure 4. Relative mean axial length of the aorta following assignement to one of the four patency status [fully patent false lumen (FL), partially patent FL, non-patent FL, and no aortic dissection (AD)—only true lumen (TL)] in patients with type B aortic dissection (TBAD) treated either by best medical treatment (BMT) or subsequent thoracic endovascular aortic repair (TEVAR) at 3, 12, 24, and 48 months follow-up (see also Supplementary Figure 1). “No AD—only TL” indicates the portion of the aorta where no AD/FL was observed (anymore). Note that TEVAR treatment reduces the relative portion of the fully patent FL, while the same is not true for the partially patent FL.

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  Figure 5. Correlation between the patent false lumen (FL) length and the number of minor side branches arising from the FL (A) Spearman's rank correlation was applied and the corresponding p-value is displayed. Forest-plot of standardized beta values for a multiple linear regression model for the axial length of the patent FL at 12 months follow-up for patients receiving thoracic endovascular repair (TEVAR) (B). Two cases of aortic remodeling following TEVAR (C). For the case on the left, the FL is partially patent prior to TEVAR (a,b) and non-patent following TEVAR (c). For the case on the right, the FL is partially patent both prior to (d) and following (e,f) TEVAR. Note that partial retrograde patency of the FL occurs which sustains blood flow to minor side branches arising from the FL prior to TEVAR.

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  Figure 6. Schematic illustration of the proposed mechanism determining false lumen (FL) patency driven by small side branches. Intimal tears are black, while green arrows indicate FL blood flow. Left: healthy aorta with no tears and no aortic dissection (AD). At the time of AD, a FL and true lumen (TL) is created through delamination of the aortic wall. Note that more than one intimal tear may occur. Upper panel: No side branches originate from the FL; all minor side branches originate from the TL. Here, the outflow is limited via re-entry tears. Stasis of blood flow is likely which might initiate FL thrombosis. Lower panel: (Multiple) Minor side branches originate from the FL and provide a continuous outflow for the blood. FL thrombosis is less likely to be initiated.