Angiotensin-converting enzyme inhibitors in heart failure

Secondary prevention of myocardial infarction: role of beta-adrenergic blockers and angiotensin-converting enzyme inhibitors

beta-Blockers reduce cardiovascular death and reinfarction in patients with a history of myocardial infarction (MI), and angiotensin-converting enzyme (ACE) inhibitors provide an overall survival benefit in patients with signs or symptoms of left ventricular (LV) dysfunction and a history of acute MI. Despite this, these agents remain underused in clinical practice. Appropriate patient selection in standard clinical practice should be encouraged in order to achieve a mortality rate reduction comparable to that seen in clinical trials. It appears from the findings of recent studies that the greatest benefit from beta-blocker therapy is achieved in patients who are more than 60 years of age and in patients at moderate or high risk for reinfarction and death (eg, patients with LV dysfunction or arrhythmias or both). Patients with class I-IV heart failure treated with ACE inhibitors have fewer recurrent infarctions, a lower incidence of severe congestive heart failure, and a reduced incidence of total cardiovascular death and sudden cardiac death. In addition to the studies completed in patients with MI, there are ongoing studies evaluating whether or not ACE inhibitors can reduce myocardial ischemic events in patients without a prior infarction who have coronary artery disease or hypertension and preserved LV function. There is also growing evidence that concomitant therapy with a beta-blocker and an ACE inhibitor may reduce mortality rates beyond that observed with ACE inhibitors alone in survivors of MI who have LV dysfunction.

Cardiac disease in chronic uremia: management

Heart disease is a common cause of morbidity in end-stage renal disease (ESRD) patients. The management of heart disease in these patients requires a multidimensional approach to the management of heart failure, coronary disease, and arrhythmias, and to risk factors such as hypertension, anemia, secondary hyperparathyroidism, and electrolyte/acid-base disturbances. Coronary artery disease management includes use of antianginal drugs and revascularization of coronary arteries with angioplasty +/- stent placement or coronary artery bypass grafting. The long-term outcomes of these procedures need to be assessed and improved. Hypertension occupies a major role in the pathogenesis of heart disease in ESRD, and early and adequate control of hypertension is likely to have a major impact on the progression of cardiac disease. This entails the achievement of optimal volume status, combined with the appropriate use of antihypertensive agents such as calcium channel blockers, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, vasodilators, alpha-blockers, and central sympatholytic drugs. In ESRD patients, specific dialysis-related complications such as intradialytic hypotension and pericardial effusion may have additional effects on cardiac function and require attention. The choice of dialysate composition and membrane may influence clinical outcomes with specific effects on cardiac performance.

Systemic and regional hemodynamic effects of perindopril in experimental heart failure

The effects of converting-enzyme inhibition by perindoprilat (0.5 mg/kg, intravenously, short-term administration) or perindopril (2 mg/kg, orally, long-term administration once a day for 21 days) on systemic and regional hemodynamics were studied on a new rat model of heart failure, which was induced by microembolization of coronary vessels by 15 microns plastic microspheres. Cardiac output and regional blood flows were measured by microsphere technique; the tone of the venous vessels was determined as mean circulatory filling pressure in conscious, freely moving rats. Perindoprilat evoked a much more prominent increase in kidneys, adrenal glands, intestine, and skin blood flows in embolized rats than in sham-operated rats. The differences between the effects of long-term treatment with perindopril in sham-operated and embolized rats were highly significant. Mean circulatory filling pressure was decreased by short-term and long-term administration of an angiotensin-converting enzyme inhibitor. It is concluded that venous vessels could be one of the target sites for the effects of perindopril-like drugs.

Safety of long-term use of lisinopril for congestive heart failure

Early clinical experience with lisinopril suggested that it was well tolerated in congestive heart failure (CHF). An analysis of data from greater than 1,000 patients treated with lisinopril has been performed to examine the long-term safety of lisinopril in CHF. Of these, 620 have been studied for up to nearly 4 years, and a further 440 have been studied in comparative trials for 3 months. When patients who received lisinopril or placebo for the same period were compared, the proportion of lisinopril patients reporting an adverse event was 44.1% compared with 39.4% on placebo. Over a 4-year period, 205 patients (33.1%) discontinued treatment. About 33% of these died, 33% withdrew due to clinical adverse events, 21 (3.4%) were withdrawn because of adverse laboratory findings, and 56 (9.0%) withdrew for reasons unrelated to treatment. Sixteen patients (2.6%) withdrew because lisinopril was deemed ineffective. The most frequently reported drug-related adverse laboratory findings were increases in blood urea nitrogen, blood urea, serum creatinine, and plasma potassium. There appeared to be no differences in the pattern of adverse events with respect to the race of the patient. Elderly patients and those with the most severe forms of heart failure appeared to be at greater risk for an adverse event. Evaluation of the safety of lisinopril compared with enalapril, captopril, and digoxin in controlled clinical trials shows all the angiotensin-converting enzyme inhibitors to be equally well tolerated with a closely similar range of adverse events, suggesting that the satisfactory safety profile of lisinopril is shared by other drugs of this class.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetic comparison of a combination tablet of enalapril and hydrochlorothiazide with enalapril and hydrochlorothiazide tablets administered together and separately

Enalapril and hydrochlorothiazide (HCT) are established single agent treatments for mild hypertension and cardiac failure and are a potent combination in more severe or resistant cases. We have compared the pharmacokinetics of enalaprilat (the active metabolite of enalapril) and HCT in a four-way comparison of a combination tablet of enalapril (10 mg)/HCT (25 mg) with a single dose of an enalapril tablet (10 mg), a single dose of a HCT tablet (25 mg) and simultaneous administration of separate tablets of enalapril (10 mg) and HCT (25 mg) in normotensive volunteers (n = 12, 21-26 years). Each subject received all four treatments and the study was conducted as a randomized, latin square, open design with at least 1 week washout between studies. Overall, HCT was bioequivalent under all conditions and enalaprilat was bioequivalent when given in combination with HCT either as one tablet or as two separate tablets. However, when given with HCT, the mean AUC and Cmax of enalaprilat were reduced up to 20 per cent compared with enalapril administered alone. This is unlikely to be of clinical significance as the differences did not reach statistical significance and the total enalaprilat excreted in the urine over 96 h was similar after all treatments.

Angiotensin-converting enzyme inhibitors and renal function

The effects of angiotensin-converting enzyme (ACE) inhibitors on renal hemodynamics vary widely depending on the preexisting physiologic and pathologic state of the kidneys. Although some studies of ACE inhibitors in primary essential hypertension have demonstrated increases in glomerular filtration rate (GFR) and effective renal plasma flow in patients with renal impairment, other studies have not shown these same beneficial results. The difference may involve the choice of ACE inhibitor used in the investigations, but controlled comparison trials are needed to determine whether this is the case. The use of ACE inhibitors in renovascular hypertension remains controversial. ACE inhibition can interfere with the autoregulation of GFR mediated by angiotensin II and may lead to deterioration of renal function, especially in patients with bilateral renal artery stenosis or stenosis of a solitary kidney. Additionally, ACE inhibitors have been shown to cause a decline in GFR in the kidney affected by the stenosis, whether or not clinically apparent renal insufficiency occurs. Although the functional impairment associated with ACE inhibitors in renal artery stenosis has generally been reversible following removal of the drug, the consequences of a long-term reduction in GFR are unknown. Treatment of stable congestive heart failure (CHF) with ACE inhibitors can result in enhancement of GFR and reduction of sodium and fluid retention, thus improving the clinical state. However, in patients with decompensated cardiac failure, renal perfusion pressures may already be at or near the autoregulatory breakpoint and ACE inhibition may cause deterioration of renal function. In general, ACE inhibitors can be used safely in CHF if they are initiated cautiously, with adjustment of ACE inhibitor and diuretic dosages to avoid systemic hypotension and sodium and fluid depletion. In studies comparing the agents, enalapril and lisinopril have both been shown to cause higher incidences of renal function deterioration than has captopril. These findings suggest that the more complete or sustained ACE inhibition seen with the longer-acting agents may be detrimental to renal function in patients with CHF. The use of ACE inhibitors in the treatment of proteinuria is the newest area of research with these agents. At present it appears that ACE inhibitors reduce urinary protein excretion the most effectively in diabetic patients with mild proteinuria and in hypertensive patients with renal insufficiency and proteinuria due to glomerular disorders. More study is needed to determine whether these agents can reduce the rate of renal failure progression and to define the patient populations expected to benefit most.(ABSTRACT TRUNCATED AT 400 WORDS)