Effects of 8,000 IU aXa long-term prophylaxis with certoparin on the incidence of hyperkalemia in patients with coronary heart disease – a post-hoc analysis of the PARAT trial

BACKGROUND: Hyperkalemia is an infrequent but potentially serious complication of low molecular weight heparin (LMWH) use. While there are a number of trials comparing LMWH to unfractionated heparin (UFH) there is no comparison of the risk with LMWH versus placebo. Aim of the present post-hoc analysis of the PARAT trial was the description of serum potassium levels with certoparin compared to placebo. RESULTS: PARAT was a double-blind, placebo-controlled, randomized trial in patients with coronary artery disease receiving either 8,000 I.U. aXa per day or placebo. Serum potassium was monitored at baseline and at scheduled follow-up visits at 2 and 4–6 weeks and 3 and 4–6 months. Statistical evaluation included paired, two sided t-test for each of the treatment groups to compare baseline and follow-up values. A total of 117 patients (59 certoparin, 58 placebo) were included with a mean age of 59 years and 84.6% male gender. There was a statistically significant increase in serum potassium at two weeks after discharge compared to baseline (p < 0.001) in either group which remained elevated throughout the three months treatment phase. Differences between treatment groups were not statistically significant. After treatment discontinuation at the three months’ visit serum potassium returned to normal values (p = n.s. vs. baseline) in both groups. Overall 12 out of 59 patients receiving certoparin (20.3%) and 11 out of 58 patients receiving placebo (19.0%) experienced hyperkalemia based on threshold of >5.0 mmol/l at any time during the observation. CONCLUSIONS: We conclude that there is no incremental risk of hyperkalemia with certoparin up to 8,000 I.U. aXa per day versus placebo in patients with coronary artery disease. The increase in serum potassium values in either group calls for clinical surveillance and the consideration of further risk factors predisposing to hyperkalemia.