Prognosis of patients with stable angina pectoris on antianginal drug therapy

Verapamil use in patients with cardiovascular disease: an overview of randomized trials

BACKGROUND

Several reports have questioned the lack of safety data on calcium antagonists as a drug class. Because this drug class is heterogeneous, unique features of certain calcium antagonists may set them apart in terms of safety and efficacy.

HYPOTHESIS

With in excess of 7,000 person-years of observation from randomized clinical trials, verapamil was selected to evaluate whether there was evidence of harm in patients with cardiovascular disease.

METHODS

MEDLINE search of English-language articles, Science Citation Index, Current Contents, manual review of cited references, pharmaceutical files, and investigator correspondence was performed. Independent review of 66 articles identified 14 randomized, parallel-group studies for inclusion. Independent, duplicate assessments were made of patient outcomes and trial characteristics (including study design, treatment dosage and schedule, duration of treatment, inclusion criteria, and sample size). Standard meta-analytic techniques were employed for analysis and interpretation of results.

RESULTS

Based on over 4,000 person-years of observation, patients with acute myocardial infarction (MI) treated with verapamil had a decreased risk of nonfatal reinfarction compared with placebo (relative risk 0.79; 2-sided 95% confidence interval 0.65.0.97; p = 0.024). Verapamil had no significant effect on overall mortality compared with placebo (relative risk ranged from 0.93; 2-sided 95% confidence interval 0.78, 1.10; p = 0.40 to 0.86; 2-sided 95% confidence interval 0.71, 1.04; p = 0.13) depending on rules used to include or exclude patients from the pooling process. For the combined outcome of death or reinfarction, verapamil use was associated with a decreased risk compared with placebo (relative risk 0.82; 2-sided 95% confidence interval 0.70, 0.97; p = 0.016). In patients with angina involving a wide spectrum of disease severity, data were limited to 2,900 person-years of observation, and verapamil use did not appear to be associated with an apparent effect on mortality or MI. Data available from randomized studies of verapamil in patients with hypertension were too limited to reach conclusions (50 person-years of observation, with no deaths or MIs reported). Subgroups of hypertensive patients in two of the largest post-MI studies and the largest angina study, involving over 600 patients, yielded little useful added information.

CONCLUSIONS

In patients with MI, the risks of both nonfatal reinfarction and the combined outcome of death or nonfatal MI were reduced over intermediate-term follow-up among patients treated with verapamil compared with controls (p = 0.024 and p = 0.016, respectively). In patients with angina, no evidence for harm was noted, but in hypertension the data were too limited to draw conclusions. These findings support the need to distinguish among different calcium antagonist compounds and to emphasize the need for more data in patients with hypertension.

Economic evaluation of the impact of nicorandil in angina (IONA) trial

OBJECTIVE

To estimate the net cost of adding nicorandil to usual treatment for patients with angina and to compare this with indicators of health benefit.

DESIGN

Cost effectiveness analysis.

SETTING

Based on results of the IONA (impact of nicorandil on angina) trial.

PATIENTS

Patients with angina fulfilling the entry criteria for the IONA trial.

INTERVENTIONS

In one arm of the trial nicorandil was added to existing antianginal treatment and compared with existing treatment alone.

MAIN OUTCOME MEASURES

Costs were for use of hospital resources (for cardiovascular, cerebrovascular, and gastrointestinal reasons), nicorandil, and care after hospital discharge. Benefits were assessed in three ways: (1) IONA trial primary outcome (coronary heart disease (CHD) death, non-fatal myocardial infarction, or hospital admission for cardiac chest pain); (2) acute coronary syndrome (CHD death, non-fatal myocardial infarction, or unstable angina); and (3) event-free survivors at the end of the trial.

RESULTS

The net cost for each additional IONA trial end point averted was -5 pounds sterling (-7 euros). The net cost for each case of acute coronary syndrome averted was -8 pounds sterling (-12 euros). The net cost for each event-free survivor was -5 pounds sterling (-7 euros). These figures are based on gastrointestinal events that were judged definitely or probably related to nicorandil. When all gastrointestinal events were included these three ratios rose to 567 pounds sterling (835 euros), 886 pounds sterling (1305 euros), and 516 pounds sterling (760 euros), respectively.

CONCLUSIONS

A substantial amount of the additional cost of nicorandil is offset by reduced use of hospital services. The limited comparisons possible with other CHD interventions suggest that nicorandil compares favourably.

The impact of diabetes or elevated fasting blood glucose on cardiovascular prognosis in patients with stable angina pectoris

AIMS

To examine the influences of diabetes and elevated fasting blood glucose on cardiovascular prognosis in patients with stable angina pectoris.

METHODS

In a prospective study of 809 patients with stable angina pectoris randomized to receive metoprolol or verapamil, a subgroup of 69 diabetic patients was compared with non-diabetic patients with respect to the risk of cardiovascular (CV) death, non-fatal myocardial infarction (MI) and revascularization. We also analysed a subgroup of 67 patients with fasting blood glucose > or = 6.1 mmol/l, defined according to the most recent revised guidelines for the diagnosis of diabetes mellitus. Fasting blood glucose was measured in venous whole blood at baseline.

RESULTS

The diabetic patients had a greater risk-factor burden, with a higher prevalence of hypertension, more likely to be male, a tendency towards a higher prevalence of previous MI, and higher triglyceride and lower high-density lipoprotein (HDL)-cholesterol levels. In multivariate analyses, diabetes was an independent risk factor for CV events with a relative risk of 2.64 (CI 1.39-5.00; P < 0.001) for CV death/MI, and 1.79 (CI 1.02-3.15; P < 0.01) for revascularization. Blood glucose > or = 6.1 mmol/l without a diagnosis of diabetes mellitus was found in 67 patients, and predicted CV death/MI [relative risk 2.76 (CI 1.97-3.84)] in both univariate and multivariate analyses. The prognosis of diabetic or hyperglycaemic patients did not differ significantly with metoprolol compared with verapamil treatment.

CONCLUSIONS

Diabetes mellitus is an independent risk factor for CV death/MI and for revascularization in patients with stable angina pectoris. Elevated fasting blood glucose was seen in 9% of patients without known diabetes and was an equally strong and independent risk factor for CV death/MI as diagnosed and treated diabetes.

The clinical characteristics and investigations planned in patients with stable angina presenting to cardiologists in Europe: from the Euro Heart Survey of Stable Angina

AIMS

The Euro Heart Survey of Stable Angina set out to prospectively study the presentation and management of patients with stable angina as first seen by a cardiologist in Europe, with particular reference to adherence to existing guidelines and regional variability in patient presentation and initial assessment.

METHODS AND RESULTS

Consecutive outpatients with a clinical diagnosis by a cardiologist of stable angina were enrolled in the study and 3779 patients were included in the analysis. The average age was 61 years and 58% were male. The majority of patients (88%) had mild to moderate angina, CCS class I or II. Despite a high prevalence of recognized risk factors, 27% did not have cholesterol and 33% did not have glucose measured within 4 weeks of assessment. The resting ECG was abnormal in 41% of patients. An exercise ECG was performed or planned as part of initial investigation in 76% of patients and 18% had a stress imaging test such as perfusion scanning or stress echo. A coronary angiogram was performed or planned in 41%, and 64% had an echo. The time from assessment to investigation varied widely, particularly for angiography. One in 10 patients had neither any form of stress test nor angiography, with marked regional variation. Availability of invasive facilities increased the likelihood of both non-invasive and invasive investigations. Those with more severe symptoms or longer duration of symptoms or a positive non-invasive test were more likely to have angiography. In multivariable analysis, a positive stress test was the strongest predictor of the use of angiography, associated with a six-fold increase in the likelihood of invasive investigation. However, gender and availability of facilities were also predictive.

CONCLUSION

Considerable variation in features at presentation and use of investigations has been identified in the stable angina population in Europe. The evaluation of biochemical cardiovascular risk factors was suboptimal. Overall rates of non-invasive investigation for angina and the clinical appropriateness of factors predictive of the use of invasive investigation were broadly in line with guidelines. However, the influence of access to facilities, and marked international variation in rates and timing of investigation suggest that factors unrelated to clinical need are also influential in the management of patients with stable angina.

A pharmacoeconomic evaluation of aggressive cholesterol lowering in Sweden

OBJECTIVE

To estimate the short-term healthcare costs and incremental cost per event avoided, associated with aggressive atorvastatin treatment in patients with acute coronary syndrome in Sweden.

METHODS

The total expected 16-week healthcare costs per patient on atorvastatin 80 mg per day and placebo were compared using clinical outcomes data from The Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) study and Swedish cost data sources. The incremental cost per event avoided was also assessed for. The clinical outcomes measured in this pharmacoeconomic analysis included: death, cardiac arrest, non-fatal myocardial infarction, fatal myocardial infarction, angina pectoris, non-fatal stroke, congestive heart failure, and surgical or percutaneous coronary revascularizations. All direct medical costs were taken into account.

RESULTS

The probability of the occurrence of an event was 40.4% per patient in the placebo cohort and 36.6% per patient in the atorvastatin cohort. The total expected cost per patient was SEK 17,887 (1950.21 euro) in the placebo group and SEK 18,465 (2013.06 euro) in the atorvastatin group, resulting in an incremental cost of SEK 578 (63.0137 euro) per patient. The cost per event avoided was SEK 15,076 (1643.64 euro). Sixty six percent of the cost of atorvastatin treatment was offset by the cost savings obtained through the reduction in the number of events in the atorvastatin group compared to the placebo group.

CONCLUSIONS

In Sweden, the clinical benefits of aggressive short-term atorvastatin treatment administered within a few days after acute coronary syndrome is associated with a substantial hospitalization cost offset secondary to the clinical benefits of atorvastatin.

Rationale and design of the International Verapamil SR/Trandolapril Study (INVEST): an Internet-based randomized trial in coronary artery disease patients with hypertension

OBJECTIVES

The primary objective of the International Verapamil SR/Trandolapril Study (INVEST) is to compare the risk for adverse outcomes (all-cause mortality, nonfatal myocardial infarction [MI] or nonfatal stroke) in hypertensive patients with coronary artery disease (CAD) treated with either a calcium antagonist-based or a noncalcium antagonist-based strategy.

BACKGROUND

Treatment recommendations for hypertension include initial therapy with a diuretic or beta-adrenergic blocking agent, for which reductions in morbidity and mortality are documented from randomized trials but are less than expected from epidemiologic data. For this reason, recent attention has focused on calcium antagonists or angiotensin-converting enzyme inhibitors. While these agents reduce blood pressure, outcome data from large randomized trials are lacking, but some case-control data, dominated by short-acting dihydropyridines, suggest an increased risk of cardiovascular events. These studies had methodologic limitations and did not differentiate among calcium antagonist types and formulations. Several studies differentiating among calcium antagonist types and an overview of published randomized trials show no increased risk with verapamil and suggestion for benefit in CAD patients.

METHODS

A total of 27,000 CAD patients with hypertension will be randomized at 1,500 primary care sites to receive either a calcium antagonist-based (verapamil) or beta-blocker/diuretic-based (atenolol/hydrochlorothiazide) antihypertensive care strategy. The study uses a novel, electronic "paper-less" system for direct on-screen data entry, randomization and drug distribution from a mail pharmacy linked to the coordination center via the Internet.

RESULTS

Contract negotiations with the United States and international sites are ongoing. Patients being enrolled are predominantly elderly (72% aged 60 years or older) men (54%), with either an abnormal coronary angiogram or prior MI (71%). In addition to hypertension, CAD and elderly age, most patients (89%) have one or more associated conditions (diabetes, dyslipidemia, smoking, cerebral or peripheral vascular disease, etc.) contributing to increased risk for adverse outcome. While 26% have diabetes, most of these are noninsulin dependent. Using the protocol strategies, target blood pressures (according to JNC VI) have been reached in 58% at the fourth visit, and as expected most (89%) are requiring multiple antihypertensive drugs.

CONCLUSION

The design and baseline characteristics of the initial patients recruited for a prospective, randomized, international, multicenter study comparing two therapeutic strategies to control hypertension in CAD patients are described.

Rationale for the use of calcium antagonists in the treatment of silent myocardial ischemia

Silent myocardial ischemia, whether it occurs at rest or during exercise, is associated with an unfavorable prognosis and may lead to sudden cardiac death. Agents used to treat silent myocardial ischemia have included nitrates, beta-blockers, and calcium antagonists (CAs). Despite treatment with traditional anti-ischemic agents, studies have shown that up to 40% of patients who receive what is considered to be clinically optimal antianginal therapy continue to have daily episodes of silent myocardial ischemia. The use of nitrates and beta-blockers is sometimes confounded by issues of tolerance and tolerability. Although the CAs have been found to be effective in decreasing the duration and frequency of episodes of silent ischemia, in general beta-blockers produce a greater reduction in these variables. Thus a need for effective and tolerable anti-ischemic agents persists. A new class of CAs, the tetralol derivatives, may show promise in this regard. The first of this new class, mibefradil, is characterized by selective blockade of T-type calcium-ion channels and has been shown in a few studies to reduce the frequency and duration of asymptomatic ischemic episodes in patients with stable exertional angina pectoris. Large-scale clinical trials are necessary before the efficacy and tolerability of this new CA can be compared fully with those of the beta-blockers and currently available CAs.

Cardiovascular prognosis in relation to apolipoproteins and other lipid parameters in patients with stable angina pectoris treated with verapamil or metoprolol: results from the Angina Prognosis Study in Stockholm (APSIS)

Relationships between apolipoproteins and other lipid parameters and cardiovascular (CV) prognosis were evaluated in the Angina Prognosis Study In Stockholm (APSIS). Out of 809 patients with stable angina pectoris, lipid variables were obtained in 786 patients at baseline, and after one month's double-blind treatment with metoprolol or verapamil, to evaluate treatment effects on these lipid variables. During a median follow-up time of 3.3 years (2663 patient years), 37 patients suffered a CV death, 30 suffered a non-fatal myocardial infarction (MI) and 100 underwent a revascularization. Apolipoprotein (apo) A-I, high-density lipoprotein cholesterol and triglycerides were predictors of CV death or non-fatal MI in univariate analyses, but only apo A-I remained as an independent predictor in multivariate analyses. All lipid variables except low density lipoprotein cholesterol were related to the risk of revascularization in univariate analyses, but only apo A-I and apo B were independent predictors of such events. Triglycerides were weakly, but not independently, associated with prognosis. Verapamil and metoprolol had differential short-term effects on lipids, with a shift towards a more atherogenic profile in metoprolol treated patients. However, there was no significant impact of the treatment given, or of these treatment effects on the risk of CV events. Results of the present study suggest that apolipoprotein levels were better predictors of CV events than other lipid parameters in patients with stable angina pectoris.

Fibrinolytic variables and cardiovascular prognosis in patients with stable angina pectoris treated with verapamil or metoprolol. Results from the Angina Prognosis study in Stockholm

BACKGROUND

Disturbed fibrinolytic function may influence the progression of coronary atherosclerosis and contribute to thrombotic cardiovascular (CV) events.

METHODS AND RESULTS

In the Angina Prognosis Study in Stockholm (APSIS), patients with stable angina pectoris were studied prospectively during double-blind treatment with metoprolol or verapamil. Various measures of fibrinolytic function were studied in 631 (of 809) patients. During a median follow-up time of 3.2 years (2132 patient-years), 32 patients suffered a CV death, 21 had a nonfatal myocardial infarction (MI), and 77 underwent revascularization. Plasma levels of tissue plasminogen activator (TPA) activity and antigen (ag), plasminogen activator inhibitor (PAI-1) activity at test, and TPA responses to exercise were determined at baseline and after 1 month's treatment and were related to subsequent fatal and nonfatal CV events. Univariate Cox regression analysis revealed that elevated levels of TPA-ag at rest (P < .05), high PAI-1 activity (P < .05), and low TPA-ag responses to exercise (P < .05) were associated with increased risk of subsequent CV death. After adjustment for baseline risk factors, TPA-ag independently predicted CV death or MI. In addition, PAI-1 activity independently predicted CV death or MI in male patients. Verapamil treatment was associated with a 10% decrease of TPA-ag levels and metoprolol treatment with a 2% increase (P < .001 for treatment difference).

CONCLUSIONS

Plasma TPA-ag levels at rest, and among male patients PAI-1 activity as well, independently predict subsequent CV death or MI in patients with stable angina pectoris.