Color-coded summation images for the evaluation of blood flow in endovascular aortic dissection fenestration

Abstract

Background: To analyze the benefit of color-coded summation images in the assessment of target lumen perfusion in patients with aortic dissection and malperfusion syndrome before and after fluoroscopy-guided aortic fenestration.

Methods: Between December 2011 and April 2020 25 patients with Stanford type A (n = 13) or type B dissection (n = 12) and malperfusion syndromes were treated with fluoroscopy-guided fenestration of the dissection flap using a re-entry catheter. The procedure was technically successful in 100% of the cases and included additional iliofemoral stent implantation in four patients. Intraprocedural systolic blood pressure measurements for gradient evaluation were performed in 19 cases. Post-processed color-coded DSA images were obtained from all DSA series before and following fenestration. Differences in time to peak (dTTP) values in the compromised aortic lumen and transluminal systolic blood pressure gradients were analyzed retrospectively. Correlation analysis between dTTP and changes in blood pressure gradients was performed.

Results: Mean TTP prior to dissection flap fenestration was 6.85 ± 1.35 s. After fenestration, mean TTP decreased significantly to 4.96 ± 0.94 s (p < 0.001). Available systolic blood pressure gradients between the true and the false lumen were reduced by a median of 4.0 mmHg following fenestration (p = 0.031), with significant reductions in Stanford type B dissections (p = 0.013) and minor reductions in type A dissections (p = 0.530). A moderate correlation with no statistical significance was found between dTTP and the difference in systolic blood pressure (r = 0.226; p = 0.351).

Conclusions: Hemodynamic parameters obtained from color-coded DSA confirmed a significant reduction of TTP values in the aortic target lumen in terms of an improved perfusion in the compromised aortic region. Color-coded DSA might thus be a suitable complementary tool in the assessment of complex vascular patterns prevailing in aortic dissections, especially when blood pressure measurements are not conclusive or feasible.

Keywords: Angiography; Aortic dissection; Color-coding; DSA; Endovascular; Fenestration.

Fig. 1

54-year-old male patient with spinal malperfusion syndrome due to acute Stanford type B aortic dissection. a Color-coded image gained from DSA prior to fenestration with ROI placement in the true lumen at the level of the infrarenal abdominal aorta. Compromised blood flow in the true lumen is represented by cold color gradients and corresponding flow curves (right corner). b After creation of two fenestration windows, the color-coded summation image demonstrates warmer color gradients at the measuring points and shortened TTP values. The arrow marks one of the fenestration windows just below the level of the renal artery

Fig. 2

45-year-old female patient with iliofemoral malperfusion syndrome of the left leg due to acute type B aortic dissection. a Preinterventional color-coded composite image demonstrates the dissection membrane affecting the distal abdominal aorta and extending in the left common iliac artery. Color gradient in the left proximal iliac segment indicates compromised blood flow with colder color gradients compared to the contralateral vessel axis. Corresponding TTP was 6.91 s. b After creation of a fenestration window at the level above the aortic bifurcation, improvement of the color gradient is demonstrated, with a TTP value of 4.44 s. Morphological improvement of vessel anatomy is also shown. Corresponding manometry did not demonstrate an improvement of the intraluminal blood pressure gradient (prior fenestration 0 mmHg; following fenestration 3 mmHg)

Fig. 3

TTP (s) prior to and following endovascular dissection flap fenestration

Fig. 4

Median systolic blood pressure gradient (mmHg) prior to and following endovascular dissection flap fenestration