Validation of transmetatarsal pressure as an alternative for evaluating severity of chronic limb-threatening ischemia.

IntroductionFew tests are validated for ischemia grading in chronic limb-threatening ischemia (CLTI). An additional, easily accessible and validated technique would be beneficial. This study aimed to determine whether transmetatarsal pressure (TMP) is valid in the evaluation of CLTI ischemia grade. We also aimed to assess if values for TMP were meaningful in patients with noncompressible ankle-brachial indices (ABI).MethodsA cohort of patients with peripheral artery disease (PAD) presenting to our vascular center from March 1 to May 1, 2022, underwent TMP measurement concurrent with ABI and toe pressure (TP) measurement. Linear and quadratic regression models were used to assess the relation between TMP and TP or ABI.ResultsA total of 108 patients who were being followed for PAD underwent testing. Half had a history of CLTI (55% of patients with diabetes and 43% of patients without diabetes). The relation between TP and TMP was best described by a quadratic formula with an R² value of 0.41. By combining the existing WIfI ischemia ranges defined by TP and the quadratic formula, new ischemia grades were calculated for TMP. Ischemia grades 0, 1, 2, and 3 corresponded to ranges of TMP pressure (mmHg) of ≥ 75, 45-74, 30-44, and < 30. There were 25 instances where a patient had an abnormally elevated ABI. None of these patients had a noncompressible TP or TMP.ConclusionWe demonstrated that TMP can be integrated into the WIfI classification. We believe that TMP evaluation may increase the reliability, accuracy, and accessibility of CLTI assessment and management.