Internal thoracic artery-inferior epigastric artery as a collateral pathway in aortoiliac occlusive disease.

OBJECTIVE

In patients with aortoiliac occlusion, the internal thoracic artery-inferior epigastric artery (ITA-IEA) collateral is one of the collaterals supplying blood flow to the lower extremity, and the interruption of this collateral may cause severe leg ischemia. The aim of this study was to evaluate by color duplex ultrasonography scans the ITA-IEA pathway and its significance as a collateral in providing lower-extremity perfusion in aortoiliac occlusive disease.

METHODS

Color duplex ultrasonography scans were prospectively performed in 64 consecutive patients with aortoiliac occlusion. Blood flow measurement in the ITA, IEA, and common femoral artery was done on both sides. The patients were stratified according to occlusion level (aorta, common iliac artery, external iliac artery), and the data obtained from such groups were compared.

RESULTS

In 95% of patients with aortoiliac occlusion, the ITA-IEA pathway was functioning as a collateral, with mean collateral flow of 66 +/- 48 mL/min, and its average contribution to lower-extremity perfusion was 38% +/- 23%. Additionally, a moderately positive correlation was found between flows of ITA and IEA (r = 0.55, P < .0001). Depending on the level of occlusion, the collateral flow and its contribution to perfusion progressively decreased from the proximal to distal aortoiliac occlusion level. Furthermore, the difference in the ITA-IEA flow volume was statistically significant between occlusion levels (P = .009), but the differences in the perfusion contribution were not different among levels (P = .311). There was also no statistical difference between the groups concerning collateral flow volume and contribution to lower-extremity perfusion in relation to unilateral or bilateral occlusion of the iliac artery, the state of distal run-off being good or poor, or the clinical findings being mild or severe.

CONCLUSION

In patients with aortoiliac occlusion, the ITA-IEA collateral pathway is an important route providing lower-extremity perfusion. Additionally, Doppler sonographic flow measurements of the contribution of the ITA-IEA route to lower-extremity perfusion may provide beneficial diagnostic information necessary for the pretreatment work-up of patients with aortoiliac occlusion, especially for whom the ITA is planned to be used as a coronary artery graft.