Imminent necrosis is indicated with Ankle brachial index of-

Ans. is 'd' i.e., <0-3 The ankle-brachial pressure index (ABPI)* The ankle-brachial pressure index (ABPI) is the ratio of systolic pressure at the ankle to that in the arm.* The higher of the pressures in the dorsalis pedis and posterior tibial arteries serves as the numerator, with the higher systolic pressure between the brachials serving as the denominator.* Resting ABPI is normally about 1.0; values below 0.9 indicate some degree of arterial obstruction and less than 0.3 suggests imminent necrosis.* It must be appreciated, however, that values approaching normality at rest may still be associated with intermittent claudication.* Retesting after exercise is useful in this context as ABPI normally rises but occlusive disease may result in reduction.* Artefacts are due especially to calcified arteries, which are often incompressible and lead to a falsely high pressure or ABPI result, especially in diabetics.