What could cause segmental pressure readings showing Rt high thigh at 110 mmHg and Lt high thigh at 164 mmHg?

Segmental pressure readings that show a significant discrepancy between the right high thigh and the left high thigh indicate a potential vascular issue affecting blood flow. In this scenario, the right high thigh reading is 110 mmHg while the left high thigh reading is considerably higher at 164 mmHg.

Aortoiliac obstruction is the most plausible cause for this difference. In cases of aortoiliac obstruction, blood flow to one side of the lower extremity can be compromised due to blockages or narrowing in the aorta and iliac arteries. This can result in lower segmental pressures on the affected side (in this case, the right side) while the unaffected side (the left side) maintains normal or elevated pressure readings due to adequate blood flow.

The other conditions listed, such as popliteal artery stenosis or proximal femoral artery occlusion, would not typically cause such a pronounced difference between segments of the thigh. They may lead to local ischemia but not to the same extent of pressure discrepancies across the thighs as observed in the question. Normal vascular function would not explain this stark difference and would show similar pressures on both sides. Thus, aortoiliac obstruction is the most consistent explanation for the differences in pressure readings observed here.