Medial artery calcification as an indicator of diabetic peripheral vascular disease

Mönckeberg sclerosis or medial artery calcification (MAC) is a well-known phenomenon associated with diabetic and other arterial disease. However, its consequence within the foot, and specifically the first dorsal metatarsal artery, has not previously been studied.

Nearly 1,000 foot x-rays were studied over a 9-month period in a busy hospital to identify the prevalence of first dorsal metatarsal artery calcification. The electronic medical notes for all the patients were reviewed to confirm which patients were known to be diabetic. The patients with positive findings were then identified and their HbA1c, creatinine, and previous foot interventions recorded.

Of the population studied, 1.4% had medial artery calcification of the 1st dorsal metatarsal artery: 93% were known diabetics and 100% had impaired glucose tolerance (a glucose plasma concentration of greater than 7.8 mmol/l 2-hours post-glucose loading). Seventy-nine percent had required previous podiatric care for foot ulceration and 64% had required surgical intervention for their diabetic feet. MAC has a high positive predictive value (92.9% (95% CI 69.2 to 98.7)) for diabetes, with a good specificity (99.9% (95%CI 99.4 to 100)) and low false positive rate (0.1% (05%CI 0.0 to 0.6)).

Medial artery calcification in the first dorsal metatarsal artery is characteristic of impaired glucose metabolism, and if seen on routine x-ray should be an indication for screening of the patient. It should also be considered as a foot-at-risk sign in the established diabetic due to the high incidence of foot ulceration and need for surgical intervention in this group.