2D perfusion angiography: an alternative method to evaluate endovascular intervention for acute lower limb ischemia

BACKGROUND: Despite advances in endovascular techniques to treat acute limb ischemia (ALI), evaluation of clinical outcomes for revascularization remains challenging, especially the accurate quantification of post-endovascular limb perfusion. This study aimed to investigate the accuracy and value of 2D perfusion angiography to evaluate endovascular intervention for ALI. METHODS: A total of 47 patients with ALI were retrospectively analyzed. The transcutaneous oxygen partial pressure (TcPO2) was obtained using laser Doppler blood perfusion monitoring. The ankle-brachial index (ABI) and angiographic images were obtained before and after endovascular intervention. iFlow imaging was used to obtain color-coded images. Regions of interest (ROIs) at the femoral head, knee joint, and ankle joint were selected to obtain the time to peak (TTP). The differences in the TTP between the knee and femoral head regions (TTP difference in the knee area) and between the ankle and knee regions (TTP difference in the ankle area) were observed. The TTP, ABI, and TcPO2 between the complete response (CR), partial response (PR), no response (NR), and amputation (AM) groups were compared. The correlation between TTP changes in the ankle area (ΔTTP) and changes in ABI (ΔABI)/changes in TcPO2 (ΔTcPO2) was analyzed. RESULTS: There was a significant increase in both TcPO2 and ABI compared with the pre-intervention values (27.75 ± 5.32 vs 40.92 ± 4.62, and 0.35 ± 0.16 vs 0.79 ± 0.15, respectively, all p < 0.01). The post-intervention TTP differences in the knee areas (5.12 ± 2.45 s) and ankle areas (6.93 ± 4.37 s) were significantly faster than pre-intervention TTP differences (7.03 ± 2.57 s and 10.66 ± 4.07 s, respectively, all p < 0.05). The post-operative TTP in the ankle area, post-operative TTP difference in the ankle area, and ΔTTP in the AM group were higher than the values in the CR and PR groups. The ΔTTP demonstrated strong correlation with ΔABI (r = −0.722, p < 0.01) and ΔTcPO2 (r = −0.734, p < 0.01). CONCLUSIONS: 2D perfusion angiography with enhanced visual and quantitative analysis exhibits great potential to evaluate the efficacy of endovascular intervention, and provides a quantitative and sensitive tool to evaluate post-endovascular limb perfusion for ALI patients.