ACE inhibitors in heart failure. What dose?

Editorial Ace inhibitors in heart failure. What dose? The role of ACE (angiotensin converting enzyme) inhibitors in the treatment of heart failure is now well established. A large body of published work has demonstrated relief of symptoms, increased exercise performance, a reduction in hospital admissions and superiority to conventional vasodilators. Three large survival studies (CONSENSUS-1,' V-HEFT II,2 and SOLVD3 have also shown that enalapril can alter the natural history of heart failure with a significant improvement in long-term prognosis. Similarly, the SAVE,4 AIRE,5 ISIS 4,6 and GISSI 37 studies demonstrated an improvement in prognosis following myocardial infarction with captopril, ramipril, and lisinopril. Many more ACE inhibitors have recently become available. The British National Formulary now lists five for the treatment of cardiac failure. The clinical benefit of these drugs to patients is beyond doubt and they now represent a cornerstone in the treatment of heart failure.8 However, there are a number of important unresolved issues with regard to their clinical use. The most important of these is the optimal dose required to achieve the full benefit of ACE inhibitor action. The target doses of the ACE inhibitor used in each study are summarised in the box. For the most part, these target doses were achieved. For example, in CONSENSUS-I the mean dose of enalapril was 18.4 mg daily. Despite these high-dose protocols market research has shown that, in general practice, much lower doses of ACE inhibitors are being used for the treatment of chronic heart failure. When enalapril is used, 42% of the doses are 5 mg or less, 75% of the doses of captopril are 75 mg or less and 65% of lisinopril prescriptions are for 10 mg or less. The information from the large outcome studies is mostly based on higher doses but it is possible that significant clinical benefit in terms of symptoms is being achieved at these lower doses. Alternatively, general practitioners may be cautious in increasing the dose ofan ACE inhibitor because they are concerned with the possibility of precipitating hypotension, reducing renal function, or causing cough. Certainly many doctors remain wary of ACE inhibitors in heart failure and refer patients to a local physician to initiate therapy in hospital. Some patients may be started on an ACE inhibitor in hospital at the lowest dose, but never have this dose increased when they return to the community. The actual reasons are, at present, unknown. However, …