Comparing the accuracy and safety of automated CO2 angiography to iodine angiography in peripheral arterial disease with chronic limb ischemia: a prospective cohort study

Diagnostic angiography of peripheral arteries using carbon dioxide (CO2) is feasible in nearly all areas below the diaphragm. Using carbon dioxide as a contrast material in angiography provides the highest quality diagnostic results in the vascular segments above the knee. However, its diagnostic reliability decreases as it moves toward the distal side of the vessels below the knee. This study investigated the diagnostic accuracy and consistency between CO2 and iodine contrast angiography in patients with peripheral vascular disease (PVD) with chronic limb ischemia (CLI). The study prospectively enrolled 35 patients with PVD and CLI and performed both CO2 and iodine contrast angiography, comparing the results for each patient. Image quality, stenosis severity, and anatomical location were analyzed. In this study, a total of 35 patients (19 male) with an average age of 56.91 ± 10.73 were examined. Among them, 13 patients (37.1%) had involvement in the femoral region, 8 patients (22.9%) in the popliteal region, 8 patients (22.9%) in the tibial region, and 6 patients (17.1%) in the foot region. CO2 angiography produced excellent image quality in 40% of cases, with good quality in another 25.7%. The quality decreased in the popliteal and foot regions. While stenosis assessment was comparable between the two methods in the femoral, popliteal, and tibial regions, there was a significant difference in the foot region. The sensitivity, specificity, positive predictive value, and negative predictive value of CO2 angiography were all 100% in the femoral and popliteal areas. However, these values were lower in the tibial and foot areas. The study concluded that the use of CO2 angiography, particularly for vascular lesions above the popliteal cavity, is a valuable and safe method for peripheral vascular examination of the lower limbs. It can serve as an alternative to iodine contrast angiography, especially in patients with kidney failure.