Fontaine classification and the ankle brachial pressure index Fontaine classification is used to stratify the severity of an underlying lower limb arterial disease as follows:
Fontaine I = Asymptomatic.
Fontaine IIa = Intermittent claudication at a distance greater than 200 meters.
Fontaine IIb = Intermittent claudications at distance less than 200 meters.
Fontaine III = Rest pain.
Fontaine IV = Ulceration and gangrene.
Ankle brachial pressure index (ABPI) is used to detect and quantify degree of arterial insufficiency, it is the ratio of systolic pressure at the ankle (posterior tibial or dorsalis pedis which ever is higher) and at brachial artery, the
normal ratio is 0.9 to 1.3, ratio less than
0.9 indicate diseased arteries, less than
0.3 indicate imminent necrosis.
Exercising the patient leads to dilatation of vascular spaces distal to an obstruction, if the feeding vessel is diseased it
cannot keep pace with increased vascular space and thus ABPI will drop furthur.
