Ankle Peak Systolic Velocity: New Parameter to Predict Nonhealing in Diabetic Foot Lesions

New Parameter to Predict Nonhealing in Diabetic Foot Lesions

Rashad A. Bishara; Wassila Taha; Ihab Akladious; Muhammad A. Allam

Disclosures

Vascular. 2009;17(5):264-268. 

In This Article

Discussion

Many noninvasive methods have been described to predict wound healing or nonhealing of foot lesions in diabetic patients. These include ankle-brachial pressure,[10] toe-brachial pressure,[10,11]transcutaneous oxygen,[11] skin perfusion pressure,[12,13,14] radioisotope clearance,[15] photoplethysmography,[16] and laser Doppler ultrasonography.[13] The utility of the ankle-brachial pressure measurement is limited by the fact that a significant proportion of diabetic patients suffer some degree of arterial wall calcification, which may render ankle pressure measurements impossible to measure or falsely elevated.[17,18] The utility of toe pressure measurement is also limited by the possibility of calcification of the digital arteries in the diabetic patients and by the ulceration or tissue necrosis of the toes of many patients, which may render toe pressure measurements inaccurate or impossible.[7] APSV is not affected by such limitations.[8]

Skin perfusion pressure at a cutoff value of 40 mm Hg has a sensitivity of 72% and a specificity of 88% in predicting wound healing.[12] Transcutaneous oxygen measurements at a cutoff value of 34 mm Hg have a sensitivity of 78.6% and a specificity of 83% in predicting wound healing.[19] The sensitivity and specificity of APSV in our study compare favorably with previously reported results of skin perfusion pressure and transcutaneous oxygen.

In this study, APSV was used to predict nonhealing and was not used to predict healing of foot lesions. If foot perfusion is significantly impaired as indicated by a low APSV, healing is unlikely. However, if foot perfusion is adequate, as indicated by a high APSV, wound healing may or may not be achieved because healing may be impaired as a result of other factors, such as infection, diabetes, renal impairment, liver impairment, and nutritional status. Therefore, it would be more appropriate to use the parameter of APSV to predict nonhealing rather than healing.

All patients included in this study were diabetic, as required in the inclusion criteria. Using the ROC curve, it was found that the cutoff value of 35 cm/s gives the highest specificity and sensitivity to predict nonhealing in this cohort of patients. It is possible that the cutoff value may be lower in nondiabetic patients. Further study is required to investigate this point.

In diabetics, both the anterior and the posterior tibial arteries are often diseased or totally occluded, the peroneal artery being the main blood supply to the foot. The peroneal artery supplies the foot through its two terminal branches, which are usually connected to the most distal segments of the anterior and posterior tibial arteries. Those are often patent, even if the two tibial arteries are otherwise severely diseased or occluded. By calculating the APSV through measurements of peak systolic velocity in the most distal segments of the anterior and posterior tibial arteries, which take their supply from the two terminal branches of the peroneal artery, the APSV effectively reflects the foot perfusion supplied through the peroneal artery.

In a 20-year literature review to assess complete ulcer healing as an end point, Hoffmann and colleagues found that this end point was reported in only 0.9% of 1,914 studies involving critical limb ischemia.[20] They questioned the appropriateness of complete ulcer healing as an end point. In this study, we used adequate healing as an end point. This is in agreement with the majority of studies reporting on wound healing in diabetic patients.

The limitations of this study are the relatively small number of limbs studied and that the new parameter APSV was used by its own inventors to investigate its value in predicting wound nonhealing. Larger studies by other groups are suggested.

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