Background and Objectives: Vascular calcification is a major contributor to morbidity and mortality in hemodialysis. The objective of this pilot study was to determine the feasibility, safety and efficacy of sodium thiosulfate (STS) in the progression of vascular calcification in hemodialysis patients. Methods: Chronic hemodialysis patients underwent a battery of cardiovascular tests. Those with coronary artery calcium (Agatston scores >50) received intravenous STS after each dialysis for 5 months (n = 22) and the tests were repeated. Changes in MDCT-determined calcification were assessed as the mean annualized rate of change in 3 vascular beds (coronary, thoracic and carotid arteries) and in L1-L2 vertebral bone density. Results: Although individual analyses showed coronary artery calcification progression in 14/22 subjects, there was no progression in the mean annualized rate of change of vascular calcification in the entire group. The L1-L2 vertebral bone density showed no changes. There were no correlations between rates of progression of vascular calcification and phosphorus, fetuin or C-reactive protein levels. Changes in coronary artery calcification scores correlated with those of the thoracic aorta. Conclusion: STS treatment is feasible, appears safe and may decrease the rate of progression of vascular calcification in hemodialysis patients. A large, randomized, controlled trial is warranted.

Ferumoxytol is a newly approved preparation of intravenous iron with a modified dextran shell that is thought to confer upon it a low immunogenic potential. Serious adverse reactions have been very uncommon in clinical studies, but these studies excluded patients with prior adverse reactions to other preparations of intravenous iron. Furthermore, the reactions were classified clinically. We report on a patient with a history of hypersensitivity to iron dextran who experienced an anaphylactic reaction after receiving ferumoxytol. Laboratory testing revealed an elevated serum tryptase level, confirming mast cell activation. This is the first laboratory-proven case of anaphylaxis related to ferumoxytol.

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