Intraindividual Variability and Association of Human Collateral Supply to Different Arterial Regions

The intraindividual variability and association of human collateral functional supply to different arterial regions is unknown. The primary study end point was collateral flow index (CFI) as obtained in the coronary artery (CA), renal artery (RA), left superficial femoral artery (SFA), and left subclavian artery (SCA) of the same individual. CFI is the ratio between simultaneously recorded mean arterial occlusive pressure divided by mean aortic pressure both subtracted by mean central venous pressure. In 100 patients admitted for diagnostic coronary angiography, CFI was assessed in 3 arterial regions (CA, RA, and SFA), 13 patients underwent CFI measurements in all 4 territories. By quantitative coronary angiography, 82 patients had a stenosis <50% in diameter in the CA who underwent CFI measurement. CFI in the CA, RA, left SFA, and left SCA region amounted to 0.110 ± 0.093, 0.119 ± 0.082, 0.512 ± 0.147, and 0.563 ± 0.155, respectively (p <0.0001). There was a direct and linear correlation between CA and SFA CFI: CFI_SFA = 0.47 + 0.47CFI_CA (r2 = 0.05; p = 0.0259). In patients with CFI values in all 4 arterial regions, an inverse linear relation between left SFA and left SCA CFI was observed: CFI_SCA = 0.91−0.67CFI_SFA (r2 = 0.36; p = 0.0305). In conclusion, intraindividual, preexistent collateral function is widely varying between different arterial supply areas. On average, collateral flow ranges from approximately 12% in comparison to flow during arterial patency in the coronary and renal circulation to over 50% in the left SFA and left SCA, that is, circle of Willi's territory. CA and SFA CFIs are directly related to each other.