SLR - August 2022 - Suzie Martikyan
Reference: Liu IH, Wu B, Krepkiy V, Ferraresi R, Reyzelman AM, Hiramoto JS, Schneider PA, Conte MS, Vartanian SM. Pedal arterial calcification score is associated with the risk of major amputation in chronic limb-threatening ischemia. J Vasc Surg. 2022 Jan;75(1):270-278.e3. doi: 10.1016/j.jvs.2021.07.235. Epub 2021 Sep 3. PMID: 34481900.Level of Evidence: Level of Evidence: III.
Scientific Literature Review
Reviewed By: Suzie Martikyan
Residency Program: DVA Puget Sound Health Care System
Podiatric Relevance: Critical limb threatening ischemia (CLTI) is one of the common manifestations of peripheral arterial disease (PAD) encountered in podiatric medicine. The ankle brachial index is not as reliable of a predictor of wound healing in patients with arterial calcification compared to those without. Thus, the need exists for a standardized tool that can better estimate the true severity of disease and limb threat in these patients. The authors hypothesized that the medial arterial calcification (MAC) score, a score obtained by calculating the length of “tram-track” calcification on plain foot radiographs, is a simple metric that can describe the burden of this disease.
Methods: A single-institution, retrospective cohort study was performed of 250 patients who had undergone infrainguinal revascularization, open or endovascular, for CLTI and had plain foot radiographs for a MAC score to be obtained. Each patient was assigned a score of 0-5 with scoring as follows: one point each was assigned for calcification of >2 centimeters in the dorsalis pedis, plantar, and metatarsal arteries, and >1 centimeter in the hallux and non-hallux digital arteries. The primary endpoint was major amputation, defined as above the ankle joint, after revascularization.
Results: The MAC score was trichotomized to create a simple and practical tool with a mild MAC score being 0-1, moderate being 2-4, and severe being 5. The MAC score was 0 in 36%, 1 in 5.2 percent, 2 in 8.4 percent, 3 in 14 percent, 4 in 14 percent, and 5 in 21 percent. A major amputation occurred in 49 of 250 patients (20 percent). A higher MAC score was significantly associated with the risk of major amputation (P < .0001). Variables that were independently associated with a higher MAC score were male sex, diabetes, end-stage renal disease, and the global limb anatomic staging system (GLASS) pedal score.
Conclusions: Peripheral arterial disease is a major cause of morbidity in the podiatric patient population, with medial arterial calcification being the most common arteriosclerotic disease process in patients with peripheral arterial disease who require major amputation. Having a prognostic indicator of disease can guide immediate vascular intervention and patient counseling. The MAC score is a marker of small-vessel disease distribution and relies on the pathophysiologic process of the disease rather than its fluctuating clinical manifestations. The results of this study show that the MAC score is a practical tool that can be derived from plain foot radiographs and is an independent predictor of major limb amputation in patients with critical limb threatening ischemia.