THE USEFULNESS OF CAPILLARY MICROSCOPY, TRANSCUTANEOUS OXIMETRY AND LASER-DOPPLER FLUXMETRY IN THE ASSESSMENT OF THE SEVERITY OF LOWER-LIMBISCHEMIA

(TM)o date, capillary microscopy, transcutaneous oximetry (tcpO(2)) an d laser Doppler fluxmetry are frequently used in the investigation of skin microcirculation in patients with lower limb ischaemia. The conco mitant microcirculatory disturbances may be useful in addition to macr ocirculatory parameters to discriminate the different degrees of ischa emic severity. The best ways of application of these methods and the c hoice of the best parameters to assess ischaemia have been insufficien tly investigated. Therefore, skin microcirculation was investigated wi th the use of these techniques in 130 patients with different stages o f lower limb ischaemia, divided according to their ankle-to-brachial p ressure index (ABI). Patients were investigated in the sitting and the supine position. Measurements were performed at rest and during react ive hyperaemia following arterial occlusion, and before and after loca l skin heating. The reactive hyperaemic response using laser Doppler f luxmetry differed in every patient group investigated. Capillary red b lood cell velocity was markedly impaired in critically ischaemic patie nts (ABI <25%). Transcutaneous oxygen pressure measurements at rest re ndered the highest positive predictive value (PV; 87%) to classify pat ients as having clinically severe ischaemia (Fontaine 3 or 4). Ankle a nd toe pressure measurements provided a PV value of 78%. Microcirculat ory parameters and techniques appear to be useful as an addition to st andard macrocirculatory techniques to assess the severity of lower lim b ischaemia. This is particularly of importance in patients in whom ma crocirculatory parameters are unattainable.