Renal siderosis in patients with heart-valve prostheses: clinical implications.

We have studied the clinical and morphological implications of renal siderosis, reviewing the autopsy protocols of 33 patients with valve prostheses in the heart. Seventeen patients had variable amounts of iron in the proximal tubules of the kidney. Renal siderosis was more frequent in women, in patients with longest time of evolution from the surgical procedure, and in patients with two valve prostheses. Histologically three degrees of renal siderosis may be defined: mild and moderate degrees of iron overload do not alter the kidney architecture, but kidneys, with severe siderosis show tubular atrophy and interstitial fibrosis. Episodes of acute renal failure (ARF) were more frequent in patients with more pronounced iron deposits, especially in the premortem stages. We conclude that renal siderosis may damage the proximal tubular epithelium of patients with valve prostheses in the heart; patients with renal overload of iron are more susceptible to episodes of ARF.