[5] Endovascular approaches, both extraluminal and transluminal, are usually indicated in patients who cannot tolerate the gold-standard treatment of surgical bypass, usually due to comorbid medical conditions that make them unsuitable for surgery.
[6] Typically, PIER is considered an indication when the transluminal approach is unable to be achieved due to anatomical complexity of the occluding lesion.
Entry is made in an antegrade fashion into the common femoral artery near the mid-femoral head using a 5-French rigid catheter with an angulated tip.
[8] A systematic review of 23 studies investigating subintimal angioplasty performed for occlusions in the femoral, femoropopliteal, and crural arteries found that the extraluminal technique achieves clinically similar outcomes as the transluminal approach.
Up until that point, the widely accepted technique was to remain within the lumen of the artery, with accidental entry of the catheter into the subintimal space typically being an indication to abort the procedure.