The QUinapril Ischemic Event Trial (QUIET) design and methods: evaluation of chronic ACE inhibitor therapy after coronary artery intervention

The rationale, trial design, and statistical aspects of QUIET, the QUinapril Ischemic Event Trial, are described. QUIET is a prospective, double-blind placebo-controlled study that will assess the ability of the angiotensin-converting enzyme (ACE) inhibitor quinapril to reduce the rate of cardiac ischemic events and to slow or prevent the development of coronary artery atherosclerosis as assessed by serial angiography in a normolipidemic population without left ventricular dysfunction. The study began in September 1991 and has completed recruitment with 1740 patients across 38 centers (28 U.S., 4 Canada, 6 Europe) by the end of 1992. Patients are randomized to 20 mg of quinapril or placebo once daily and continue in the study for 3 years. Study completion is projected for 1995.

Therapy of left ventricular dysfunction: implications of recent therapeutic trials and future directions for therapy

The natural history of patients with heart failure has changed relatively little until recently. Several large randomized trials have however recently changed our approach to the patient with symptomatic as well as asymptomatic left ventricular dysfunction. Although the effect of digoxin on survival is still uncertain there is still good evidence from the Radiance study in which patients were randomly withdrawn from digoxin that patients who remain on digoxin have a significant improvement in exercise tolerance and well being. The Consensus trial in patients with class IV heart failure suggested that ACE inhibitors were effective in improving survival. This therapy has not however been widely adapted in patients with mild to moderate heart failure. The recent randomized SOLVD treatment trial in conjunction with the VHEFT II study clearly shows that ACE inhibitors should be the basis for therapy along with a diuretic and digoxin if necessary in all patients with symptomatic left ventricular dysfunction unless contraindicated or not tolerated. There is also evidence from the SOLVD prevention trial that ACE inhibitors can prevent the development of manifest heart failure and hospitalization for heart failure in patients with asymptomatic left ventricular dysfunction. The importance of ACE inhibitors in patients with asymptomatic left ventricular dysfunction is confirmed by data from the SAVE trial which examine both symptomatic and asymptomatic patients with left ventricular dysfunction 3-16 days post infarction. Of interest in both the SOLVD treatment and prevention trials as well as the SAVE trial was the finding that ACE inhibitors reduced the incidence of recurrent ischemic events.(ABSTRACT TRUNCATED AT 250 WORDS)

Early reocclusion after successful thrombolysis is related to lesion length and roughness

BACKGROUND

Reocclusion is a significant problem after thrombolysis. Results of previous studies conflict regarding the association of various features of postlytic lesions that might predict reocclusion.

METHODS

A computer-assisted algorithm was therefore used to quantitatively measure edge roughness in the 90-minute postlysis angiogram of 84 patients receiving recombinant tissue plasminogen activator within 6 hours of chest pain.

RESULTS

Twenty-five patients had reocclusion, and 59 did not. The baseline angiogram showed no differences between these two groups with respect to minimal dimensions or relative percentage of stenosis. Length was greater in the reocclusion group (12.2 +/- 5.0 vs 10.0 +/- 4.2 mm, P < 0.05). Three of four roughness indices based on curvature analysis indicated greater roughness in those patients with reocclusion. These differences were largely due to the increased length of these lesions. The scaled edge-length ratio, an index of roughness that is independent of length, was, however, significantly greater in the reocclusion group (1.15 +/- 0.10 vs 1.09 +/- 0.08, P < 0.006). Multiple regression analysis showed that lesion length, the scaled edge-length ratio, and the number of features (invaginations and evaginations) per cm correlated independently with the risk for reocclusion.

CONCLUSIONS

The length and roughness of postlytic residual lesions are determinants of reocclusion.

A prospective evaluation of the hepatotoxicity of lofepramine in the elderly

Lofepramine has been acclaimed as an effective and safe antidepressant, particularly for the elderly. Recent case reports of hepatic toxicity following treatment with lofepramine, however, caused clinicians to question its use in a patient population who frequently have concomitant physical illness. From published data the incidence of serious side effects as well as the implications for its use remain unclear. In this study, 52 patients over the age of 65 years treated with lofepramine were monitored over a 12-week period. The results suggest that for the overwhelming majority of patients, any rise in liver enzyme activity is transient. It is recommended, however, that LFTs be monitored for the first 12 weeks of treatment.

Effect of enalapril on myocardial infarction and unstable angina in patients with low ejection fractions

An association between raised renin levels and myocardial infarction has been reported. We studied the effects of enalapril, an angiotensin-converting enzyme (ACE) inhibitor, on the development of myocardial infarction and unstable angina in 6797 patients with ejection fractions < or = 0.35 enrolled into the two Studies of Left Ventricular Dysfunction (SOLVD) trials. Patients were randomly assigned to placebo (n = 3401) or enalapril (n = 3396) at doses of 2.5-20 mg per day in two concurrent double-blind trials with the same protocol. Patients with heart failure entered the treatment trial (n = 2569) and those without heart failure entered the prevention trial (n = 4228). Follow-up averaged 40 months. In each trial there were significant reductions in the number of patients developing myocardial infarction (treatment trial: 158 placebo vs 127 enalapril, p < 0.02; prevention trial: 204 vs 161 p < 0.01) or unstable angina (240 vs 187 p < 0.001; 355 vs 312, p < 0.05). Combined, there were 362 placebo group patients with myocardial infarction compared with 288 in the enalapril group (risk reduction 23%, 95% CI 11-34%; p < 0.001). 595 placebo group patients developed unstable angina compared with 499 in the enalapril group (risk reduction 20%, 95% CI 9-29%, p < 0.001). There was also a reduction in cardiac deaths (711 placebo, 615 enalapril; p < 0.003), so that the reduction in the combined endpoint of deaths, myocardial infarction, and unstable angina was highly significant (20% risk reduction, 95% CI 14-26%; p < 0.0001). Enalapril treatment significantly reduced myocardial infarction, unstable angina, and cardiac mortality in patients with low ejection fractions.

Effect of enalapril on mortality and the development of heart failure in asymptomatic patients with reduced left ventricular ejection fractions

BACKGROUND

It is not known whether the treatment of patients with asymptomatic left ventricular dysfunction reduces mortality and morbidity. We studied the effect of an angiotensin-converting--enzyme inhibitor, enalapril, on total mortality and mortality from cardiovascular causes, the development of heart failure, and hospitalization for heart failure among patients with ejection fractions of 0.35 or less who were not receiving drug treatment for heart failure.

METHODS

Patients were randomly assigned to receive either placebo (n = 2117) or enalapril (n = 2111) at doses of 2.5 to 20 mg per day in a double-blind trial. Follow-up averaged 37.4 months.

RESULTS

There were 334 deaths in the placebo group, as compared with 313 in the enalapril group (reduction in risk, 8 percent by the log-rank test; 95 percent confidence interval, -8 percent [an increase of 8 percent] to 21 percent; P = 0.30). The reduction in mortality from cardiovascular causes was larger but was not statistically significant (298 deaths in the placebo group vs. 265 in the enalapril group; risk reduction, 12 percent; 95 percent confidence interval, -3 to 26 percent; P = 0.12). When we combined patients in whom heart failure developed and those who died, the total number of deaths and cases of heart failure was lower in the enalapril group than in the placebo group (630 vs. 818; risk reduction, 29 percent; 95 percent confidence interval, 21 to 36 percent; P less than 0.001). In addition, fewer patients given enalapril died or were hospitalized for heart failure (434 in the enalapril group; vs. 518 in the placebo group; risk reduction, 20 percent; 95 percent confidence interval, 9 to 30 percent; P less than 0.001).

CONCLUSIONS

The angiotensin-converting--enzyme inhibitor enalapril significantly reduced the incidence of heart failure and the rate of related hospitalizations, as compared with the rates in the group given placebo, among patients with asymptomatic left ventricular dysfunction. There was also a trend toward fewer deaths due to cardiovascular causes among the patients who received enalapril.

Eicosapentaenoic acid inhibits endothelium-dependent relaxation to acetylcholine in guinea pig coronary resistance vessels

Dietary supplementation with eicosapentaenoic acid (EPA) alters arachidonate metabolism. This study characterizes the effect of dietary EPA on endothelium-dependent vasodilation to acetylcholine (ACH) and ATP in guinea pig coronary resistance vessels. Guinea pigs were fed standard chow (n = 6), standard chow+sesame seed oil (n = 6), or standard chow+menhaden fish oil (17% EPA; n = 6). Coronary vasodilations were examined in the isolated, potassium-arrested heart utilizing a modified Langendorff preparation. Coronary vessels were constricted with prostaglandin F2 alpha and relaxed with ACH (5.5 x 10(-9)-10(-6) moles) or ATP (10(-10)-10(-7) moles). Endothelium-dependent dilations to ACH, but not ATP, were attenuated by dietary supplementation with EPA. To assess the role of the endothelium in modulating vascular responses to agonists following dietary manipulation, the perfusate was stimulated by electrolysis (9 V, 4 Hz, 2 msec) in order to generate free radicals, which we have shown to preferentially damage the endothelium. After endothelial damage, responses to ACH, ATP, and nitroprusside were similar between the dietary groups. In an additional group of standard diet animals (n = 6) experiments were performed to assess the role of prostanoid metabolism in affecting coronary vascular reactivity. Perfusion of hearts with indomethacin (14 microM) reduced endothelium-dependent vasodilations to ACH (5.5 x 10(-9)-10(-6) moles), but not to ATP (10(-10)-10(-7) moles). After endothelial damage, infusion of ACH resulted in vasoconstriction, whereas vasodilation responses to ATP were absent. We conclude that dietary supplementation with EPA inhibits endothelium-dependent dilations to ACH in guinea pig coronary microvessels. These diet-related differences in vascular reactivity may be related to the fish-oil-induced alteration of vasodilator prostaglandin metabolism. In the coronary bed, different endothelial factors appear to mediate relaxation to ACH and ATP.

Congestive heart failure: new therapeutic strategies

Angiotensin converting enzyme inhibitors (ACE-I) are widely used in patients with severe heart failure on the basis of the significant improvement in mortality in the CONSENSUS-I trial in patients with Class IV heart failure. Recent data from the 5-year clinical trial Studies of Left Ventricular Dysfunction (SOLVD) suggest a role for ACE-I in patients with mild to moderate heart failure as well as in those with asymptomatic left ventricular dysfunction. The SOLVD treatment trial in patients with a left ventricular ejection fraction (LVEF) less than or equal to 35% and treated for heart failure with conventional therapy including digitalis, diuretics, or vasodilators demonstrated that the addition of enalapril resulted in a significant reduction in mortality from heart failure as well as in the combined end point of death plus hospitalization from heart failure. These data suggest that ACE-I should be the base of therapy for patients with mild to moderate heart failure, as well as for those with severe heart failure.

Is the tyramine test for depressive illness useful in elderly patients?

There were no significant differences in tyramine sulphate excretion following tyramine ingestion between elderly depressed, demented or control patient groups, in contrast with younger subjects where this test is a trait marker for unipolar endogenous depression. There are inherent problems in urine collection studies in the elderly and the results may have been influenced by the medication that elderly patients have to take for other disorders. This study suggests that the tyramine test is unlikely to be of clinical usefulness in the over 65 age group.

The effect of treatment on survival in congestive heart failure

Congestive heart failure (CHF) is a disorder characterized by a variety of clinical, biochemical, electrophysiological, and hemodynamic abnormalities. During the past two decades, numerous drugs have been employed in the treatment of this complex syndrome, and many agents have been shown to improve symptoms and ventricular function in patients with CHF. Because CHF is associated with a high risk of death, treatment should be directed not only toward the relief of symptoms, but also toward a reduction in mortality. Many variables have been shown to be related to survival; taken individually, however, each is limited in its utility in predicting prognosis. In recent years, large-scale studies with large sample sizes have directly assessed the effects of treatment on mortality in CHF. Results from these trials indicate that vasodilators and angiotensin-converting enzyme (ACE) inhibitors may improve mortality in patients with symptoms of heart failure. Additional trials are now in progress to evaluate the effect of treatment on patients with asymptomatic left ventricular dysfunction.

Prognostic importance of quantitative analysis of coronary cineangiograms

Many studies have shown the prognostic value of angiographic data, but few have examined quantitative parameters of wall motion and shape or coronary stenosis severity. To determine whether these parameters have prognostic importance, baseline angiograms of 283 patients with up to 11.2 years (mean 8.3) of follow-up were quantitated. Event-free survival curves were constructed using log-rank testing. These indexes were also considered in 2 predictive models (Cox regression models): 1 with ("clinical") and 1 without ("quantitative") subjective angiographic analysis and clinical information. Regional shape (anterior and inferior walls) and motion (anterior wall only) indexes were predictive of event-free survival when considered singly. But these parameters were not of independent prognostic importance in the regression models. The most important independent parameters in the quantitative model for predicting overall cardiac mortality or an initial lethal cardiac event were the ejection fraction and the percent diameter narrowing of each major coronary artery. Myocardial infarction was predicted by the percent diameter stenosis of the left main and left anterior descending arteries but not the ejection fraction. In the clinical model, the factors of overriding prognostic importance were the ejection fraction and the subjective determination of the number of vessels involved with "significant" stenoses. Quantitative coronary arteriography still contributed independent prognostic value. Thus, quantification of the ejection fraction and severity of coronary lesions were of independent, prognostic importance, whereas indexes of regional function and shape were not.

The role of beta-adrenergic blocking agents in preventing sudden cardiac death

The failure of encainide and flecainide to reduce mortality after infarction in the Cardiac Arrhythmia Suppression Trial and the failure of low-dose amiodarone to prevent sudden cardiac death in patients with a low left ventricular ejection fraction has shifted attention to other strategies, such as beta-adrenergic blocking agents, to prevent sudden cardiac death. Evidence suggesting that beta-adrenergic blocking agents might be useful, especially in patients with low left ventricular ejection fraction, is accumulating. Previous data from studies using beta-adrenergic blocking agents and the mechanisms by which beta-adrenergic blocking agents might be of value in preventing sudden cardiac death are reviewed. These considerations and the availability of new investigational beta-adrenergic blocking agents with vasodilator properties provide a new opportunity to test the hypothesis that beta-adrenergic blocking agents are useful in preventing sudden cardiac death, especially in patients with a low left ventricular ejection fraction.

A monoclonal antibody against the platelet glycoprotein IIb/IIIa receptor complex prevents platelet aggregation and thrombosis in a canine model of coronary angioplasty

BACKGROUND

The comparative effects of aspirin and F(ab')2 fragments of monoclonal antibody 7E3 against the platelet glycoprotein IIb/IIIa receptor on ex vivo platelet aggregation and in vivo thrombosis were studied in a canine coronary balloon angioplasty model.

METHODS AND RESULTS

Three groups were studied. Group 1 (n = 8) was pretreated with saline placebo, group 2 (n = 8) was pretreated with 325 mg aspirin, and group 3 (n = 8) was pretreated with 0.8 mg/kg 7E3 F(ab')2. Coronary angioplasty was performed in the left anterior descending coronary artery of open-chest dogs under fluoroscopic control; serial measurements of basal and hyperemic coronary blood flows were then made for 2 hours after application of an external stenosis that decreased hyperemic flow by 50%. There were no significant differences in platelet counts or hemodynamic measurements during the experiments. Platelet aggregation was decreased by treatment: group 1, 64 +/- 13% versus 50 +/- 13% (p = NS); group 2, 57 +/- 4% versus 25 +/- 4% (p less than 0.001); and group 3, 77 +/- 5% versus 10 +/- 6% (p less than 0.0002). Compared with initial measurements, the 7E3 antibody was superior to aspirin in maintaining hyperemic coronary blood flow after release of the external stenosis: group 1, 177 +/- 14 versus 21 +/- 14 ml/min (p less than 0.0003); group 2, 189 +/- 9 versus 110 +/- 28 ml/min (p less than 0.008); and group 3, 194 +/- 12 versus 181 +/- 15 ml/min (p less than 0.02). In group 1, arterial occlusion developed in five dogs, and nonocclusive thrombus was seen in three dogs. In group 2, arterial occlusion developed in one dog, and nonocclusive thrombus was seen in five dogs. No thrombotic material was visualized in group 3 dogs treated with 7E3 F(ab')2.

CONCLUSIONS

In this animal model, the 7E3 antiplatelet antibody is superior to aspirin in inhibiting platelet aggregation, thrombosis, and acute closure after deep arterial injury caused by coronary balloon angioplasty.

Prospective, double-blind, placebo-controlled trial of low-dose amiodarone in patients with severe heart failure and asymptomatic frequent ventricular ectopy

Sudden cardiac death is a common cause of mortality in patients with congestive heart failure. To determine if low-dose amiodarone could reduce sudden death among these patients, a prospective, placebo-controlled, double-blind pilot trial was conducted. One hundred one patients with ejection fractions less than 30%, New York Heart Association class III or IV symptoms, and frequent but asymptomatic spontaneous ventricular ectopy (Lown class II to V) were randomly assigned to treatment with low-dose amiodarone (400 mg/day for 4 weeks and then 200 mg/day) or placebo. Mean follow-up was 357 days (range 4 to 1009 days). Side effects were infrequent and there was no difference in the incidence of side effects between the treatment groups. The frequency of spontaneous ventricular ectopy in the group receiving amiodarone fell from 4992 +/- 1240 beats/24 hours at baseline to 1135 +/- 494 beats/24 hours after 1 month of treatment (p = 0.02) and remained low after 6 months, while there was no change in ventricular ectopy among the patients receiving placebo. Despite the reduction in ectopy, there was no improvement in mortality or decrease in the incidence of sudden death. One-year mortality by Kaplan-Meier analysis was 28% in the group receiving amiodarone and 19% in the group receiving placebo (p = NS). One-year mortality in patients with greater than 75% reduction in ventricular ectopy after 1 month of treatment was 31% versus 17% in patients with less than or equal to 75% ectopic suppression (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Prospects for the use of antagonists to the platelet glycoprotein IIb/IIIa receptor to prevent post-angioplasty restenosis and thrombosis

Despite many advances since its inception in humans in 1977, coronary angioplasty continues to be limited by the problems of abrupt arterial closure and late restenosis. Excessive platelet deposition at the site of angioplasty undoubtedly plays an important role in the pathophysiology of both of these problems. Monoclonal antibodies and snake venom-derived or synthetic peptides directed against a common protein recognition sequence on the platelet glycoprotein IIb/IIIa receptor are currently in the early stages of preclinical and clinical testing and hold promise of preventing abrupt closure and restenosis by inhibiting platelet function. Whether any of these agents will eventually be commonly used in clinical practice will depend on their effects on the complex pathophysiology of these problems and on their safety profile when administered to patients who are likely to receive other antithrombotic medications and who are instrumented for coronary angioplasty.

A randomized placebo-controlled trial of combined early intravenous captopril and recombinant tissue-type plasminogen activator therapy in acute myocardial infarction

The adjunctive use of intravenous captopril with tissue plasminogen activator early during acute myocardial infarction offers theoretic advantages of diminishing left ventricular volume, preventing ventricular dilation and improving patient survival. To test the safety and efficacy of combined early administration of intravenous captopril and recombinant tissue-type plasminogen activator (rt-PA), 38 patients treated with rt-PA 3 +/- 0.3 h (mean +/- SE) after the onset of myocardial infarction were randomized to intravenous followed by oral captopril or placebo therapy. They underwent cardiac catheterization with measurement of hemodynamic variables and left ventricular function and determination of serum renin, angiotensin and aldosterone levels on days 1 and 7. Oral administration of the selected agent was continued for 3 months along with other antianginal medications, including nonangiotensin-converting enzyme inhibitor vasodilators. Repeat measurements of left ventricular function were obtained before hospital discharge and at 3 months. There were no significant differences in baseline clinical characteristics between groups. One patient in the captopril-treated group became hypotensive during intravenous therapy, requiring discontinuation of treatment. Compared with the placebo-treated group, the captopril-treated group had significant reductions at day 7 in left ventricular end-diastolic pressure (22.5 +/- 1.5 versus 16.3 +/- 1.6 mm Hg, p less than 0.01) and mean systemic arterial pressure (93.6 +/- 3.3 versus 86.2 +/- 2.7 mm Hg, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)