Table 1.

Criteria for distal protection methods. IVUS: intravascular ultrasound.

(i) Worsening symptoms and signs

(1) Newly onset (<6 months) of claudication

(2) Shortend walking distance

(3) Pain at rest

(4) Ulceration or gangrene of extremities

(ii) Angiographic features

(1) Contrast stain at the occlusion site

(2) Contrast defect due to thrombus

(iii) Mild resistance on the wire manipulation

Easy pass through the CTO lesion by a guidewire

(iv) IVUS findings

(1) Poorly echogenic plaque

(2) Mobile plaque

(3) Homogeneous plaque of mildly raised echogenicity

(4) Plaque with small blood flow channels