Virtual Histology to Evaluate Mechanisms of Pulmonary Artery Lumen Enlargement in Response to Balloon Pulmonary Angioplasty in Chronic Thromboembolic Pulmonary Hypertension

Figures

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  Figure 1. Schematic presentation of the pulmonary artery (PA) segment occupied by an organized thromboembolic lesion The external elastic membrane is depicted with the grey color. Dashed blue line enclosed by the external elastic membrane constituted the overall segment cross-sectional area (E-CSA in the text). The lumen of the stenosed PA segment (L-CSA in the text) is depicted by yellow dashed line.

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  Figure 2. Flowchart presenting the selection of the stenosed pulmonary arterial segments. Abbreviations: BPA—balloon pulmonary angioplasty; IVUS—intravascular ultrasound.

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  Figure 3. Distribution of changes in cross-sectional area (CSA) of the lumen, pulmonary artery stenosed segment and the organized thrombus after balloon pulmonary angioplasty. (n = 98). Both L-CSA and the E-CSA increased (∆ = 1.4(0.7–2.4) mm2; p < 0.001 and ∆ = 1.0(0.1–2.8) mm2; p < 0.001), respectively). There was no change in the T-CSA (∆ = −0.1(−1.3; 0.7) mm2; p = 0.23). The lines and boxes represent medians and interquartile (IQR) ranges. The width of the whisker is calculated as a 2*IQR. The points represent values outside the range denoted by whiskers. Abbreviations: E-CSA—pulmonary artery stenosed segment cross-sectional area; L-CSA—lumen cross-sectional area; T-CSA—organized thrombus cross-sectional area.

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  Figure 4. Changes in the organized thrombus composition in the type B (n = 49) response to BPA. There was an overall decrease in the T-CSA by 0.9 (−2.0; −0.1) mm2; p = 0.001. The L-CSA increased by 0.8 (0.6–1.7) mm2; p = 0.001 along with the decrease in the amount of light-green component (0.4 (−1; 0] mm2; p = 0.005). There was no significant change in the dark-green (∆ = −0.15 (−0.8; 0.3) mm2; p = 0.07), red (∆ = 0 (−0.2; 0.3) mm2; p = 0.65) and white (∆ = 0 (0; 0.1) mm2; p = 0.56) components of the organized thromboembolic lesions. Abbreviations: BPA—balloon pulmonary angioplasty; CSA—cross-sectional area; L-CSA—lumen cross-sectional area; T-CSA—organized thrombus cross-sectional area.