Development of the MCA/PTA Diameter Ratio as a Predictor of Response After Superselective Embolization for Plantar Fasciitis: A Preliminary Derivation Study.

PURPOSE: To evaluate whether the medial calcaneal artery (MCA) to posterior tibial artery (PTA) diameter ratio predicts pain reduction after superselective MCA embolization in chronic plantar fasciitis. MATERIALS AND METHODS: Thirty-eight patients (mean age 46.8 ± 10.2 years; 63.2% female) with chronic plantar fasciitis refractory to ≥6 months of conservative treatment and baseline visual analog scale ≥6 were included in this single-center retrospective study. After superselective MCA catheterization, embolization was performed with imipenem/cilastatin. Preprocedural digital subtraction angiography was used to measure MCA and PTA diameters and calculate the MCA/PTA ratio. The primary endpoint was VAS change at 1 month. Predictive performance was assessed with receiver operating characteristic analysis and linear mixed models. RESULTS: Mean VAS decreased from 8.2 ± 0.9 at baseline to 2.2 ± 0.6 at 1 month (p < .001) and 2.9 ± 0.7 at 6 months. The MCA/PTA ratio had a strong effect on VAS (β = -8.97, p < .001) with a significant time × ratio interaction (p < .001). The ratio predicted clinical success (VAS ≤3 at 1 month) with an area under the curve of 0.91 (95% CI: 0.80-0.99; p = .001). The optimal cutoff was 0.48 (sensitivity 100%, specificity 84.2%). High-ratio patients (>0.48) showed sustained pain relief through 6 months, whereas low-ratio patients experienced recurrence. Interobserver agreement was excellent. CONCLUSION: The MCA/PTA diameter ratio is associated with early and durable pain relief after superselective MCA embolization. A cutoff of 0.48 shows promise as an angiographic predictor but requires prospective multicenter validation.