Using Pedal Acceleration Time To Predict Ischemic Wound Healing In Diabetic Patients

Diabetes Mellitus is one of the main factors for peripheral arterial disease (PAD), while also being associated with medial arterial calcification, thus limiting the use of the ankle-brachial index. Pedal acceleration time (PAT), has emerged as a diagnostic alternative, by measuring the systolic acceleration in the arteries of the foot, with higher PAT values corresponding to a worse prognosis and with the literature suggesting a cut-off of 180 ms as a predictor of wound healing. We aimed to confirm whether we could use PAT to predict wound healing, need for revascularization and amputation in diabetic patients and whether this cut-off was valid in our population.

A retrospective cross-sectional study was carried on diabetic patients referred to our department with PAD and lower limb wounds. Each limb was assessed individually in case of bilateral wounds. Limbs with unmeasurable PAT were excluded. Limbs were assessed on follow-up and classified as: healed wounds (HW), non-healed wounds (NHW), revascularized or amputated. PAT cut-off for wound healing was measured with ROC curve. Significance was defined at p≤0.05.

A total of 88 patients and 100 limbs were included, mostly males (80.68%) with a median age of 75 years. Cut-off for wound healing was validated at 180.5 ms. Among the assessed limbs, 26% HW, 31% NHW, 33% revascularized limbs and 7% amputations. Mean PAT in each group was 159.81 ms (HW), 199.32 ms (NHW), 239.18 ms (revascularized), 279.14 ms (amputated). When comparing the HW and NHW groups, 61.3% of NHW had PAT >180ms versus 19.2% HW, p<0.001 (OR=6.65; 95%CI [1.98-22.39]). In the sub-set of NHW we further analysed whether the wound was clinically better or worse: wounds with a positive healing process had a mean PAT of 189.96 ms vs 231.43 ms (p=0.14) in wounds with worse evolution.

The results of our study validate the cut-off of 180 ms and reinforce using PAT as a predictor for wound healing, even among diabetic patients. In our analysis, only patients with HW had mean PAT ≤180 ms, with higher values of PAT being associated with worse outcomes (need for revascularization/amputation). Furthermore, in NHW patients, those with a PAT closer to 180 ms were associated with more favourable wound healing outcomes.