Which artery's ligation is most likely to result in tissue loss due to limited collateral circulation?

Popliteal Artery Ligation Most Likely Results in Tissue Loss

Tissue loss almost always results from ligation of the popliteal artery (option a). The popliteal artery is most likely to result in tissue loss when ligated due to limited collateral circulation beyond this vessel.

Anatomical Considerations and Collateral Circulation

• The popliteal artery is particularly vulnerable to causing tissue loss when ligated because there is a paucity of collateral vascular pathways beyond these lesions, making them more commonly associated with limb-threatening ischemia 1
• Popliteal artery ligation carries a significant risk of amputation or severe chronic ischemia due to inadequate collateral circulation 1
• In contrast, the superficial femoral artery (SFA) rarely causes advanced forms of ischemia when occluded in isolation because the deep femoral artery provides substantial collateral circulation to reconstitute the popliteal artery 1
• Postoperative ischemia and claudication occur in 33% to 97% of patients following popliteal artery ligation, with limb amputation rates of 5% to 33% 1

Comparison with Other Arterial Occlusions

• Superficial femoral artery (SFA) occlusion is the most common lesion associated with intermittent claudication but rarely leads to tissue loss due to collateral circulation via the deep femoral artery 1
• Common femoral artery occlusion is serious but has better collateral potential than popliteal occlusion through the deep femoral artery network 1
• Brachial artery occlusion can cause ischemia but has better collateral circulation through the radial-ulnar arch 2
• Portal vein is not an artery and its occlusion leads to portal hypertension rather than tissue loss 1

Clinical Evidence Supporting Popliteal Vulnerability

• The American Heart Association notes that popliteal artery ligation in cases of mycotic aneurysms results in higher rates of tissue loss compared to other arterial ligations 1
• In cases of popliteal artery aneurysm with thrombosis, up to 19% of patients may require amputation despite surgical repair, highlighting the critical nature of this vessel 3
• Collateral studies have shown that the majority of collateral vessels in the lower limb connect to the H3-P1 segment (distal adductor channel and proximal popliteal artery), making this region critical for limb perfusion 4

Anatomical Distribution of Collaterals

• Research has identified 113 collateral vessels in the lower limb: 69 originated from the deep femoral artery, 34 from the superficial femoral artery, and only 10 from the popliteal artery, demonstrating the limited collateral network from the popliteal artery itself 4
• The deep femoral artery provides significant collateral circulation to the superficial femoral artery (57% of collaterals), explaining why SFA occlusion rarely causes tissue loss 4
• The popliteal artery's position posterior to the knee joint makes it vulnerable during knee hyperextension or hyperflexion, which can further compromise collateral flow 5

Management Implications

• Due to the high risk of tissue loss with popliteal artery occlusion, the American College of Cardiology recommends immediate intervention for acute popliteal artery occlusion 2
• For popliteal artery aneurysms, repair is strongly recommended for aneurysms ≥2.0 cm in diameter to prevent thromboembolic complications and limb loss 3
• When popliteal artery repair is necessary, endoaneurysmorrhaphy using a posterior approach with interposition grafting shows excellent limb salvage rates of 100% 6

In conclusion, the popliteal artery's limited collateral network and critical position in the lower limb vascular tree make it the vessel most likely to result in tissue loss when ligated, compared to the other options presented.