2D-Perfusion Angiography Using Carbon Dioxide (CO2): A Feasible Tool to Monitor Immediate Treatment Response to Endovascular Therapy of Peripheral Arterial Disease?

Purpose: Patients with peripheral arterial disease (PAD) or critical limb ischemia (CLI) require revascularization. Traditionally, endovascular therapy (EVT) is performed with iodinated contrast agent (ICM), which can provoke potential deterioration in renal function. CO2 is a safe negative contrast agent to guide vascular procedures, but interpretation of CO2 angiography is challenging. Changes in blood flow following iodine-aided EVT are assessable with 2D-perfusion angiography (2D-PA). The aim of this study was to evaluate 2D-PA as a tool to monitor blood flow changes during CO₂-aided EVT.

Material and methods: 2D-PA was performed before and after ten EVTs (nine stents; one endoprosthesis; 10/2012-02/2020) in nine patients (six men; 65 ± 10y) with Fontaine stage IIb (n = 8) and IV (n = 1). A reference ROI (ROI_INFLOW) was placed in the artery before the targeted obstruction and a target ROI (ROI_OUTFLOW) distally. Corresponding ROIs were used pre- and post-EVT. Time to peak (TTP), peak density (PD) and area under the curve (AUC) were computed. The reference/target ROI ratios (TTP_OUTFLOW/TTP_INFLOW; PD_OUTFLOW/PD_INFLOW; AUC_OUTFLOW/AUC_INFLOW) were calculated.

Results: 2D-PA was technically feasible in all cases. A significant increase of 82% in PD_OUTFLOW/PD_INFLOW (0.44 ± 0.4 to 0.8 ± 0.63; p = 0.002) and of 132% in AUC_OUTFLOW/AUC_INFLOW (0.34 ± 0.22 to 0.79 ± 0.59; p = 0.002) was seen. A trend for a decrease in TTP_OUTFLOW/TTP_INFLOW was observed (- 24%; 5.57 ± 3.66 s-4.25 ± 1.64 s; p = 0.6).

Conclusion: The presented 2D-PA technique facilitates the assessment of arterial flow in CO2-aided EVTs and has the potential to simplify the assessment of immediate treatment response.