Grade	Category	Clinical description	Objective criteria
	0	Asymptomatic, no hemodynamically significant occlusive disease	Normal results of treadmill/stress test
I	1	Mild claudication	Treadmill exercise completed, postexercise AP is greater than 50 mmHg but more than 25 mmHg less than normal
	2	Moderate claudication	Symptoms between those of categories 1 and 3
	3	Severe claudication	Treadmill exercise cannot be completed, postexercise AP is less than 50 mmHg
II	4	Ischemic rest pain	Resting AP of 40 mmHg or less, flat or barely pulsatile ankle or metatarsal plethysmographic tracing, toe pressure less than 30 mmHg
III	5	Minor tissue loss, nonhealing ulcer, focal gangrene with diffuse pedal ischemia	Resting AP of 60 mmHg or less, ankle or metatarsal plethysmographic tracing flat or barely pulsatile, toe pressure less than 40 mmHg
	6	Major tissue loss, extending above transmetatarsal level, functional foot no longer salvageable	Same as for category 5

AP ankle pressure.