Clinical reliability and utility of skin perfusion pressure measurement in ischemic limbs - Comparison with other noninvasive diagnostic methods

Purpose: We studied whether the measurement of skin perfusion pressure (SPP) is useful for evaluating ischemic limbs and predicting wound healing. Methods: Two hundred eleven patients (age range, 45 to 90 years; mean age, 69.6 +/- 9.2 years; 170 men and 41 women), 403 limbs with arteriosclerosis obliterans, were included in this study. Half of the patients had diabetes or were receiving dialysis or both. Results. Significant correlations were found between SPP and ankle blood pressure (ABP), SPP and toe blood pressure (TBP), and SPP and the transcutaneous oxygen pressure (tcPO(2)) (P <.0001, r = 0.75; P <.0001, r = 0.85; P <.0001, r = 0.62; respectively). In 94 limbs with ulcer or gangrene, wound healing was predicted by the SPP. The mean SPP (mean +/- SD) in the healed-wound group (25 limbs, 48 +/- 20 mm Hg) was greater than that in the unhealed-wound group (69 limbs, 23 +/- 11 mm Hg) (P <.001). According to the receiver operating characteristic (ROC) curve, the cut-off value of SPP was 40 mm Hg (sensitivity, 72%; specificity, 88%). Furthermore, we studied whether the combination of SPP and another measurement could predict wound healing more accurately than could any single variable. There was a strong correlation between SPP, TBP, and the healing rate (P <.001, r = 0.69) and healing could be accurately predicted if the SPP was greater than 40 mm Hg and if the TBP was greater than 30 mm Hg. Conclusions: Our results suggest that measurement of SPP is an objective method for assessing the severity of peripheral arterial disease or for predicting wound healing.