Correspondence (letter to the editor): Severe Renal Insufficiency

The molecular-weight-dependent risk of accumulation of low-molecular-weight heparins (LMWH) in the setting of renal failure is widely accepted. Unfortunately, the attribution of diagram 2 was omitted (from the work of S. Alban). Fondaparinux is discussed in the article as if it were comparable to enoxaparin; one must realize, however, that the cited study by Büller et al. (1) excluded patients with an elevated creatinine concentration – yet it is precisely these patients who so often present for treatment, among others, in everyday practice.

A look at the information for physicians with regard to fondaparinux reveals that even a moderate degree of renal insufficiency led to hemorrhagic complications in 6.6% of patients, while severe renal insufficiency did so in 14.5%. The figures for enoxaparin are similar; this clearly indicates that low molecular weight, renal function, and hemorrhagic tendency are closely associated with one another. Fondaparinux is absolutely contraindicated in patients with severe renal insufficiency. For enoxaparin, an adjustment of the dose is recommended, yet treating physicians often will not even know whether renal insufficiency is present, let alone how severe it is. Protamine is available as an antidote for low-molecular-weight heparins, but no such antidote is available for fondaparinux. In view of these facts, I think it is rather bold to call fondaparinux "a good alternative" to heparins. At most, one can say that it might be an alternative if there is a reason why low-molecular-weight heparins cannot or should not be given.