The effectiveness and relative effectiveness of intravenous inotropic drugs acting through the adrenergic pathway in patients with heart failure-a meta-regression analysis.

AIMS To review systematically the use of intravenous (IV) inotropic agents acting through the adrenergic signalling pathway, compared with placebo or an active agent, in patients with heart failure. METHODS Studies investigating the use of intravenous inotropes in patients with heart failure published between 1966 and 2000 were identified using MEDLINE, the Cochrane register and Embase databases. Reference lists from relevant papers and reviews were hand searched for further papers. In total, 21 trials, that included 632 patients receiving IV inotropic drugs, placebo or non-treatment control, were identified. Drugs of the following classes were included, the beta-agonists; dobutamine, high-dose (>2.5 microg/kg/min) dopamine, dopexamine and the phosphodiesterase (PDE) inhibitors; amrinone, milrinone, enoximone and toborinone. Sixteen trials (474 patients) contributed data from acute invasive haemodynamic studies of symptomatically severe heart failure. Five trials (158 patients) were based on intermittent inotropic therapy in an outpatient context. RESULTS With few exceptions, trials of intravenous inotropic agents were small and often failed to report clinically important outcomes. Compared to placebo, intravenous inotropic agents acting through the adrenergic system tended to increase mortality (odds ratio 1.50 (95% CI=0.51 to 3.92) but this did not reach significance and insufficient data were available to determine whether symptoms improved. There appeared to be little difference in the effect of beta-agonists compared to PDE inhibitors on patient outcomes but this could be attributed to the paucity of data. CONCLUSIONS Intravenous inotropic agents acting through the adrenergic pathway are often used in patients with worsening heart failure to achieve arbitrary haemodynamic targets. Our analyses show that there is very little evidence that such treatment improves symptoms or patient outcomes and may not be safe. This highlights the need for further well designed randomised clinical trials.