Pediatric Iatrogenic Vascular Injury

Lower Extremity and Femoral Artery

Iatrogenic arterial occlusions of the lower extremity in children resulting in limb loss are very rare. The preponderance of femoral artery occlusions are caused by transfemoral catheterization, either for cardiovascular diagnostic purposes or, less commonly, for arterial line insertion. Placement of larger devices, such as for percutaneous procedures on the aorta or aortic valve or for extracorporeal membrane oxygenation (ECMO) are additional recognized causes of femoral artery occlusions.

In the acute setting there may be overt signs of malperfusion such as a pale, cold extremity, pain or paresthesias, mottling of the skin, and absent arterial Doppler signals. In severe cases a purple or gray discoloration of the toes or forefoot may be evident. The latter rarely occurs unless the arterial occlusion is combined with shock and/or intravenous vasoactive drugs.

In the very young, an isolated femoral artery occlusion unaccompanied by critical limb ischemia may be treated conservatively with heparin anticoagulation. The relative effectiveness of the collateral circulation in these circumstances usually preserves limb viability. Similarly, the patient in shock and requiring ongoing pharmacologic support might not be a candidate for an immediate operation even in the setting of severe ischemia, and anticoagulation may be the only reasonable therapy. In any instance where distal malperfusion of the lower extremity occurs, if a catheter is still in place it should be removed immediately.

An open revascularization may become necessary if limb-threatening ischemia exists or progressive ischemic injury occurs. Resection and primary repair may be possible in cases of a very focal occlusion. Interrupted sutures with spatulation of the involved vessels, so as to create ovoid anastomoses, will lessen the risk of later narrowing at the anastomosis. A small vein patch may be used if a primary arterial repair is precluded by the extent of the injury. Long-term follow-ups of vein patches have not been reported, although small case series with short-term follow-up support this option. More extensive injuries can require bypass with reversed saphenous vein ( Figures 1 and 2 ). Late aneurysmal deterioration of such vein grafts used in reconstructing extremity arteries occurs less often than when they are used for renal arterial reconstructions. Nevertheless, long-term follow-up of any vein graft (or patch) in children is mandatory. Late vein graft failure as a result of neointimal hyperplasia or thrombosis has been reported in 5% of patients.

If these injuries are managed nonoperatively and the occlusion does not recanalize, or if collateral circulation is ultimately insufficient, then certain subtle complications can ensue. These include complaints of pain with ambulation and potential retardation of long-bone growth with subsequent limb length discrepancies and gait abnormalities. Limb length discrepancy is not a rare occurrence following arterial catheterization in young patients, and length disparity rates of 8% are reported following femoral artery access in children 5 years old or younger. These events often go unrecognized as a result of the development of extensive collaterals, restoring palpable pulses in the affected extremity ( Figure 3 ).

It is intuitive that the incidence of arterial complications is higher in children in whom larger arterial access is undertaken. In a 1990 review of 64 consecutive infants and children who underwent transfemoral arterial access for balloon dilation of the aorta or aortic valve, almost 50% had some type of acute iliofemoral complication. Thrombosis was most common, but complete or partial arterial disruption occurred in 13%. The sheath access size in these patients was 8 or 9 Fr. With continued improvements in percutaneous endovascular devices since this report, it may be assumed that the current incidence of arterial complications is lower.

Extremity ischemia requiring an intervention occurs in more than 50% of children undergoing arterial access for venoarterial ECMO. In this special subgroup of children, where the overall mortality is very high, those with lower extremity ischemia who underwent surgical treatment had a mortality rate of 27%.