Hindlimb collateral growth after superficial femoral artery (SFA) ligation in the Ossabaw pig

Vascular compensation to femoral artery occlusion was assessed in the Ossabaw pig. In 6 pigs, the right SFA was ligated and 4 weeks later, angiograms of the proximal hindlimbs were obtained using fluoroscopy. An average of 7.2±1.6 collaterals identified as vessels responsible for reconstitution of distal femoral artery originated from the superficial femoral, profunda (deep femoral) and gluteal arteries. The greatest number originated from the profunda (4.0±0.8), but the most prominent (>1 mm diameter) from the gluteal. Histology of the collaterals showed a tremendous increase in a single layer of intimal cells, an intact internal elastic lamina and no neointima. The inner diameter of the common femoral determined by intravascular ultrasound was similar between limbs, 5.0±0.4 mm. Average peak velocity in the common femoral measured with a ComboWire™XT was similar between limbs (19±2 vs 20±2, p=0.68), but decreased ∼50% with acute compression of the SFA. MAP was 64±5 mm Hg at time of velocity measurement. In conclusion, remarkable collateral growth occurs in the young healthy Ossabaw pig, which is able to restore resting flow in the common femoral artery within 4 weeks post‐occlusion. The Ossabaw pig is an excellent model to assess the impact of vascular disease on collateral growth in vessels of comparable size and hemodynamics as in humans. Support: HL42898, RR013223 , HL062552