Royal Liverpool University Hospital, Renal Unit, Liverpool UK Email: fen{at}doctors.org.uk
Sir,
Whilst Hausmann's [1] comments with respect to the tolerability of aldactone in peritoneal dialysis patients are important, we believe the data is over interpreted. The RALES study [2] included only individuals with, at worst, moderate renal impairment and normal baseline serum potassium. Additionally, Hausmann's patient was not receiving a loop diuretic or an ACE-inhibitor compared with 100% and 95%, respectively, of individuals randomized to aldactone in this study. In RALES, renal function was discriminatory in terms of survival analysis in those individuals with a serum creatinine of >107 mmol/l at randomization. Bauersachs et al. [3], demonstrated in Wistar rats following myocardial infarction that the combination of trandolopril and aldactone induced a striking increase in urinary sodium losses, leading to improved left ventricular haemodynamics when compared with either compound alone. This natureitic response is unlikely to exist in renal failure. It is unjustified in patients with more advanced renal disease to extrapolate the potential benefits seen in RALES. Furthermore, there may have been no additional therapeutic benefit in those individuals not already established on ACE-inhibitor therapy prior to the introduction of aldactone. The 95% confidence interval for the relative risk of all cause mortality in those not receiving ACE inhibititors can be seen to cross 1.0. Hyperkalemia is obviously more likely to occur when using ACE-inhibition and aldactone in renal failure and preclude the use of this combination.
It is more likely in our opinion that the benefits in the presented case are due to revascularization rather than any pharmacological effects on the myocardium. It is well documented that despite the burden of cardiovascular disease in our patients they undergo less coronary interventions. This case does however highlight that consideration for revascularization is appropriate in end-stage renal failure, but fails to convince that aldactone had anything other than a marginal effect.
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