Cost estimates for treatment of cardiac ischemia (from the Asymptomatic Cardiac Ischemia Pilot [ACIP] study)

Costs for management of myocardial ischemia are enormous, yet comparison cost and outcome data for various ischemia treatment strategies from randomized trials are lacking and will require cost and resource utilization data from a large prospective trial. The Asymptomatic Cardiac Ischemia Pilot provided feasibility data for planning such a trial and an opportunity to estimate the long-term costs of different treatment strategies. Economic implications for ischemia management were compared in 558 patients with stable coronary artery disease and myocardial ischemia during both stress testing and daily life. Participants were randomized to 3 different initial treatment strategies and followed for 2 years. Based on cost trends over follow-up, costs for subsequent care were estimated. As expected, due to initial procedural costs, at 3 months, estimated costs for revascularization were approximately 10 times greater than costs for a medical care strategy. Extrapolated costs for anticipated resource consumption for care beyond 2 years, however, were approximately 2 times greater for an initial medical care strategy than for initial revascularization. This was due to increased need for drugs and hospitalizations for both late revascularizations and other ischemia-related events. Estimated costs for anticipated care in the medical strategies reached the anticipated cost of the revascularization strategy within 10 years. Because this cost-equal time period is well within the median life expectancy for such a patient population, these findings could have important public health implications and require testing in a full-scale prognosis trial. We anticipate that over the patients' life expectancy, early revascularization is likely to become either cost-neutral or cost-effective.

Efficacy and safety of sildenafil citrate in the treatment of erectile dysfunction in patients with ischemic heart disease

Erectile dysfunction is a common condition in men with cardiovascular disease, probably as a result of shared factors that impair hemodynamic mechanisms in the penile and ischemic vasculature. Sildenafil citrate, an orally active, selective inhibitor of phosphodiesterase type 5 (PDE5), has demonstrated excellent efficacy and safety profiles in men with erectile dysfunction of various etiologies. Sildenafil administration is contraindicated in patients who are taking nitrates or nitric oxide donors. This retrospective subanalysis of data from double-blind, placebo-controlled studies assessed the efficacy (9 studies) and safety (11 studies) of sildenafil in patients with erectile dysfunction and ischemic heart disease who were not taking nitrates. Of 3,672 patients randomized to receive sildenafil (5-200 mg) or placebo for 4-24 weeks in 11 double-blind, placebo-controlled studies, 357 (10%) reported a history (past or present) of ischemic heart disease and were not taking nitrates. Efficacy was assessed using end-of-treatment responses to Question 3 (ability to achieve an erection) and Question 4 (ability to maintain an erection) of the International Index of Erectile Function (IIEF), scores for the 5 domains of male sexual function assessed by the IIEF (erectile function, orgasmic function, sexual desire, intercourse satisfaction, and overall satisfaction), and responses to a global efficacy question ("Did the treatment improve your erections?"). The responses to the 2 IIEF questions were graded on a scale of 1 (almost never or never) to 5 (almost always or always), with a score of 0 indicating no attempt at sexual intercourse. At the end of treatment, the mean scores for Question 3 and Question 4 of the IIEF for patients with erectile dysfunction and ischemic heart disease were significantly higher for the sildenafil group than for the placebo group (p <0.0001). Mean end-of-treatment scores for the IIEF domains also demonstrated significant increases for sildenafil-treated patients compared with those receiving placebo (p <0.05). At the end of treatment, improved erections were reported by 70% of patients who received sildenafil and by 20% of those in the placebo group p <0.0001). For the sildenafil group, the incidences of the most common adverse events (headache 25%, flushing 14%, and dyspepsia 12%) for patients with ischemic heart disease were similar to those in patients without this concomitant illness (21%, 15%, and 10%, respectively). Moreover, the overall incidence of cardiovascular adverse events other than flushing was comparable in patients with and without ischemic heart disease for both treatment groups. Since there is a degree of cardiac risk associated with sexual activity, clinicians should consider the patient's cardiovascular status before initiating any treatment for erectile dysfunction. Physicians should be aware that patients with underlying cardiovascular disease could be adversely affected by the vasodilator effects of sildenafil, especially in combination with sexual activity. The results of the present subanalysis indicate that oral sildenafil significantly improves erectile function and is well tolerated in patients with erectile dysfunction and ischemic heart disease who are not taking nitrate therapy.

Factors influencing clinical outcomes after revascularization in the asymptomatic cardiac ischemia pilot (ACIP). ACIP Study Group

BACKGROUND AND AIM

The Asymptomatic Cardiac Ischemia Pilot is the first randomized trial where revascularization involved choice of either coronary bypass or angioplasty used in an early or a delayed symptom-driven approach. One-year outcomes were favorable (reduced recurrent ischemia and adverse outcomes) for an early revascularization strategy (within 4 weeks), compared with an early medical strategy when revascularization was delayed until symptom-driven. This ancillary study examined variables influencing outcomes after these 2 revascularization approaches (early vs. delayed until symptom-driven).

METHODS

Participants were clinically stable coronary disease patients with stress-induced and daily life ischemia who underwent revascularization. Characteristics associated with clinical outcomes occurring within the year following revascularization were examined using Cox regression analysis.

RESULTS

A total of 262 patients received revascularization; 170 in the early approach and 92 in the delayed symptom-driven approach. Thirty-three patients had adverse outcomes (death, nonfatal myocardial infarction, or repeat revascularization) during 1-year follow-up. The most important independent predictor of improved outcome during the follow-up year was attempted revascularization of > or = 66% of vessels with significant stenosis for the early (risk ratio [RR] 0.25, 95% confidence interval [CI] 0.09-0.67) and the delayed (RR 0.21, CI 0.08-0.58) approaches. Factors such as age, stress test results, and coronary angiographic findings did not predict clinical outcome.

CONCLUSIONS

Our findings are important in the planning of a large trial with longer follow-up.

Why we should attempt to eliminate (silent and symptomatic) ischemia in patients with chronic stable angina

There is no doubt that angina patients with symptomatic ischemia face a poor prognosis and that treatment of these patients is necessary. However, there is no consensus regarding the prognostic value or treatment of silent ischemia in patients with stable angina. It is in this context that the advantages of treating silent ischemia are presented.

Management strategies for a better outcome in unstable coronary artery disease

Unstable coronary artery disease is a term encompassing both unstable angina and non-Q-wave (non-ST-segment elevation) myocardial infarction. Patients with these conditions are at risk of early progression to acute myocardial infarction and death. Thus, management of these conditions must aim to reduce long-term mortality and morbidity. Risk stratification is crucial for the identification of patients whose risk of early progression is high; they may require coronary angiography and (if suitable) either percutaneous transluminal coronary angioplasty or coronary artery bypass surgery. No single variable can accurately predict risk, but considerable data are emerging to show that biochemical markers of myocardial injury, such as troponin-T and troponin-I, are valuable in combination with electrocardiographic findings and clinical features. Routine early invasive procedures (coronary angiography with or without revascularization) have not yet been shown to have any significant advantage over conservative regimens for the majority of patients. Antiplatelet, anticoagulant, and anti-ischemic agents remain the mainstay of treatment in the acute phase. New agents, such as glycoprotein IIb/IIIa receptor inhibitors and low-molecular-weight heparins, as well as antithrombins and Factor Xa inhibitors add to the treatments currently available. Thrombolytic agents are contraindicated in the absence of ST-segment elevation. After clinical stabilization, ongoing assessment should include exercise testing for all patients who are able; other imaging techniques should be used for patients unable to exercise. A profile indicating a high risk of future events is an indication for elective angiography and consideration for revascularization.

Prognostic significance of myocardial ischemia detected by ambulatory electrocardiography, exercise treadmill testing, and electrocardiogram at rest to predict cardiac events by one year (the Asymptomatic Cardiac Ischemia Pilot [ACIP] study)

Myocardial ischemia identified by ambulatory electrocardiography (AECG), exercising treadmill testing, (ETT), or 12-lead electrocardiogram at rest is associated with an adverse prognosis, but the effect of improving these ischemic manifestations by treatment on outcome is unknown. The Asymptomatic Cardiac Ischemia Pilot (ACIP) study was a National Heart, Lung, and Blood Institute funded study to determine the feasibility of conducting a large-scale prognosis study and to assess the effect of 3 treatment strategies (angina-guided strategy, AECG ischemia-guided strategy, and revascularization strategy) in reducing the manifestations of ischemia as indicated by AECG and ETT. The study cohort for this database study consisted of 496 randomized patients who performed the AECG, ETT, and 12-lead electrocardiogram at rest at both the qualifying and week 12 visits. The effect of modifying ischemia by treatment on the incidence of cardiac events (death, myocardial infarction, coronary revascularization procedure, or hospitalization for an ischemic event) at 1 year was examined. In the 2 medical treatment groups (n = 328) there was an association between the number of ambulatory electrocardiographic ischemic episodes at the qualifying visit and combined cardiac events at 1 year (p = 0.003). In the AECG ischemia-guided patients there was a trend associating greater reduction in the number of ambulatory electrocardiographic ischemia episodes with a reduced incidence of combined cardiac events (r = -0.15, p = 0.06). In the revascularization strategy patients this association was absent. In the medical treatment patients the exercise duration on the baseline ETT was inversely associated with an adverse prognosis (p = 0.02). The medical treatment strategies only slightly improved the exercise time and the exercise duration remained of prognostic significance. In the revascularization group strategy patients this association was absent. Thus, myocardial ischemia detected by AECG and an abnormal ETT are each independently associated with an adverse cardiac outcome in patients subsequently treated medically.

Relation between clinical, angiographic and ischemic findings at baseline and ischemia-related adverse outcomes at 1 year in the Asymptomatic Cardiac Ischemia Pilot study. ACIP Study Group

OBJECTIVES

We attempted to investigate the relation between patient characteristics and adverse outcome in patients with ischemia and clinically stable coronary artery disease (CAD).

BACKGROUND

Evidence suggests that cardiac ischemia, detected by exercise stress testing (ETT) and ambulatory electrocardiographic (AECG) monitoring during daily living, identifies a subgroup of patients at increased risk for adverse outcome, but the relation between these ischemia findings and clinical and angiographic characteristics is largely unknown.

METHODS

We examined the relation between clinical, angiographic and ischemia characteristics at entry with adverse outcome observed at 1 year in the 558 patients enrolled in the Asymptomatic Cardiac Ischemia Pilot (ACIP) study.

RESULTS

By the 12-month visit 13.1% of patients had an ischemia-related adverse clinical outcome that included death, nonfatal myocardial infarction or an ischemia-related hospital admission. Multivariate analysis identified only the number of AECG ischemic episodes at entry (odds ratio [OR] 1.06, 99% confidence interval [CI] 1.01 to 1.12, p = 0.002) as an independent predictor of outcome. Assignment to revascularization (as opposed to an initial medical treatment strategy) showed a trend (OR 0.56, 99% CI 0.26 to 1.2, p = 0.05). None of the other baseline clinical, exercise or angiographic variables examined provided additional information relative to adverse outcome.

CONCLUSIONS

Determinants of adverse outcome, among clinically stable patients with CAD and ischemia induced by stress and daily life were magnitude of AECG ischemia before treatment and, possibly, initial treatment assignment. Among the many other characteristics examined, including age, symptom status and angiographic and exercise variables, none contributed additional independent prognostic information. These two simple variables, which may be modifiable, need further study in a larger trial.

Treatment of ischaemic heart disease. Role of drugs, surgery and angioplasty in unstable angina patients

The term unstable angina should only be used to describe patients whose immediate prognosis is uncertain and the nature of the unstable disease may vary on a patient to patient basis, making broad categorization of such patients inappropriate. Unstable angina may be caused by extracardiac factors, such as uncontrolled hypertension and tachycardia, disruption of an atheromatous plaque, dynamic or intermittent coronary artery thrombosis, haemorrhagic dissection into an atheromatous plaque, epicardial coronary spasm or progression of atherosclerosis as a result of plaque healing. Control of symptoms using medical therapy with a combination of nitrates, beta-blockers and calcium antagonists is usually quite successful. In the absence of contra-indications, intravenous heparin, and possibly anti-platelet agents, should also be used in the acute phase of treatment. In addition, one aspirin a day is indicated unless there are definite contra-indications. If symptoms are relieved, evaluation and management should proceed as with chronic stable angina. Identification of patients with a poor prognosis should be the main indication for urgent revascularization. One of the best predictors of a poor prognosis in unstable disease is persistent pain despite optimum therapy. Urgent surgery should be considered in any patient with multivessel coronary artery stenosis who has evidence of persistent myocardial ischaemia, despite adequate medical therapy.

Asymptomatic Cardiac Ischemia Pilot (ACIP) study two-year follow-up: outcomes of patients randomized to initial strategies of medical therapy versus revascularization

BACKGROUND

Patients with ischemia during stress testing and ambulatory ECG monitoring have an increased risk of cardiac events, but it is not known whether their prognosis is improved by more aggressive treatment with anti-ischemic drugs or revascularization.

METHODS AND RESULTS

The Asymptomatic Cardiac Ischemia Pilot study randomized 558 such patients who had coronary anatomy suitable for revascularization to three treatment strategies: angina-guided drug therapy (n=183), angina plus ischemia-guided drug therapy (n=183), or revascularization by angioplasty or bypass surgery (n=192). Two years after randomization, the total mortality was 6.6% in the angina-guided strategy, 4.4% in the ischemia-guided strategy, and 1.1% in the revascularization strategy (P<.02). The rate of death or myocardial infarction was 12.1% in the angina-guided strategy, 8.8% in the ischemia-guided strategy, and 4.7% in the revascularization strategy (P<.04). The rate of death, myocardial infarction, or recurrent cardiac hospitalization was 41.8% in the angina-guided strategy, 38.5% in the ischemia-guided strategy, and 23.1% in the revascularization strategy (P<.001). Pairwise testing revealed significant differences between the revascularization and angina-guided strategies for each comparison.

CONCLUSIONS

A strategy of initial revascularization appears to improve the prognosis of this population compared with angina-guided medical therapy. A larger long-term study is needed to confirm this benefit and to adequately test the potential of more aggressive drug therapy.

Dobutamine echocardiography for prediction of ischemic events in heart transplant recipients

The purpose of this study was to assess the use of dobutamine stress echocardiography in predicting cardiac events in heart transplant recipients. Dobutamine echocardiography was performed in 63 consecutive heart transplant recipients, 52 males and 11 females ranging in age from 12 to 77 years (mean 54), undergoing routine yearly evaluation. Twenty-one patients had abnormal wall motion at baseline or during dobutamine infusion. Over a mean follow-up of 8 months (range 4 to 14), there were six major cardiac events: five occurred among patients with abnormal echocardiography study results; only one event occurred in a patient with a normal echocardiography result. These data suggest that normal wall motion during dobutamine echocardiography identifies a subset of heart transplant recipients at low risk for development of cardiac events, whereas an abnormal study result serves as an important predictor of subsequent cardiac events.

Anginal status and prediction of cardiac events in patients enrolled in the asymptomatic cardiac ischemia pilot (ACIP) study. ACIP investigators

We hypothesized that among the patients enrolled in the Asymptomatic Cardiac Ischemia Pilot (ACIP) trial, those who reported angina either within the previous 6 weeks or experienced angina during ambulatory electrocardiographic (ECG) monitoring during activities of daily life or during stress testing would be more likely to experience an adverse cardiac event within a year than those who did not experience angina. Of the 558 patients enrolled in ACIP, 325 (58.2%) reported angina in the previous 6 weeks, 300 (53.8%) had stress-induced angina, and 63 (11.3%) reported angina during activities of daily life associated with ST-segment changes on the 48-hour ambulatory electrocardiogram. Some patients had > 1 of these angina symptoms and thus 8 angina status categories were identified. Adverse cardiac events were defined as death, nonfatal myocardial infarction (MI), or hospitalization for ischemic events, which included revascularization not specified by the ACIP protocol. One hundred and sixty-seven patients (29.9%) were asymptomatic (i.e., they never had angina) by our defined criteria. Three hundred ninety-one patients (70.1%) were symptomatic. Symptomatic patients had a higher incidence of death, MI, or hospitalization for ischemic events (15.3% symptomatic vs 7.8% asymptomatic, p = 0.016). History of angina within 6 weeks before randomization was predictive of death, MI, or hospitalization for ischemic event (p = 0.007). This finding was due to a large difference in the need for hospitalizations which would be expected to be driven by the presence of angina. By contrast, angina during ambulatory electrocardiogram or stress test was not predictive of an adverse cardiac event. The asymptomatic status of coronary disease patients who have objective documentation of ischemia is not uniformly defined and many different categories can be identified. In this population of patients with proven coronary artery disease and myocardial ischemia, a history of angina in the previous 6 weeks was a good predictor of an adverse event occurring in the next year.

A detailed angiographic analysis of patients with ambulatory electrocardiographic ischemia: results from the Asymptomatic Cardiac Ischemia Pilot (ACIP) study angiographic core laboratory

OBJECTIVES

The purpose of this Asymptomatic Cardiac Ischemia Pilot (ACIP) data bank study was to characterize angiographic features of coronary pathology of patients enrolled in the ACIP study.

BACKGROUND

Ischemia during ambulatory electrocardiographic (AECG) monitoring is associated with increased morbidity and mortality. Reports relating AECG ischemia to severity or complexity of coronary artery disease are few in number and small in size and have produced conflicting results.

METHODS

Coronary angiograms from patients with asymptomatic AECG ischemia enrolled in the ACIP study were reviewed at a central core laboratory. Quantitative measurement of percent stenosis and Thrombolysis in Myocardial Infarction flow grades were used to assess the severity of coronary artery disease. Lesions were also evaluated for the presence of intracoronary thrombus, ulceration and lumen contour as indicators of stenosis complexity. In addition, comparisons were made with 27 patients screened for the ACIP study, but who were found ineligible because they did not have AECG ischemia on 48-h Holter monitoring.

RESULTS

A total of 329 (75%) of 439 patients with AECG ischemia had multivessel coronary artery disease. Proximal stenoses > or = 50% diameter reduction were common in patients with AECG ischemia (62.2%), as were proximal stenoses > or = 70% (38.7%). Features suggesting complex plaque were found in 50.1% of patients with AECG ischemia.

CONCLUSIONS

Multivessel coronary artery disease, severe proximal stenoses and features of complex plaque were observed frequently in patients who exhibited AECG ischemia. The presence of severe and complex coronary artery disease may explain, in part, the increased risk for adverse outcome associated with ischemia during activities of daily life.

Re-examining the clinical safety and roles of calcium antagonists in cardiovascular medicine

Despite recent analyses questioning the safety of calcium antagonists, evidence and clinical practice strongly support a major role for these drugs in the management of many cardiovascular diseases such as arrhythmia, vascular spasm, hypertension, diastolic dysfunction, stable angina, and myocardial infarction. These agents are a heterogeneous class of drugs with each formulation possessing unique properties and clinical applications. This article presents a review of the available literature and discusses the recommended use of various calcium antagonists in the treatment of diseases of the heart and vascular system.

Asymptomatic Cardiac Ischemia Pilot (ACIP) Study. Relationship between exercise-induced and ambulatory ischemia in patients with stable coronary disease

BACKGROUND

We investigated whether the presence and frequency of asymptomatic ischemic episodes recorded during ambulatory ECG (AECG) monitoring could be predicted on the basis of clinical characteristics or exercise treadmill test (ETT) performance in patients with stable coronary disease and whether the estimate of ischemia severity was similar between the AECG and ETT.

METHODS AND RESULTS

Patients screened for the Asymptomatic Cardiac Ischemia Pilot (ACIP) study were selected for the current analysis if data were available from 48-hour AECG monitoring as well as from an ETT during which the patient developed > or = 1-mm ST-segment depression. Exercise ECG data were available for 143 of the 910 patients without ischemic episodes and for 659 of the 910 patients with ischemic episodes during AECG monitoring. Angina was more frequent among patients with ambulatory ischemic episodes than among patients without such ischemia (P < .001). Patients with AECG ischemia had a consistently more marked ischemic response on the ETT than patients without AECG ischemia; patients likely to have AECG ischemia could be predicted on the basis of ETT performance characteristics. However, the correlation coefficients between the severity of ischemia estimated by ETT and by AECG were small.

CONCLUSIONS

There are significant relations between ischemia detected by AECG monitoring and by ETT, but the relations are limited, indicating that the two tests are not redundant to characterize coronary patients. A larger study investigating the prognostic significance of the ischemia identified by each modality, with follow-up for clinical events, will be necessary to determine the most appropriate methods to evaluate patients with stable coronary disease.

Clinical trials: are they really useful for clinical decision making?

I have always maintained that clinical trials are important to provide prognostic information in patients with cardiac disease. However, clinical trials provide prognostic information for the population of patients under study. I still believe that clinical trials provide knowledge and information that improves patient care. As physicians, we should use the results of clinical trials as guidelines for decision making in individual patients. If we are to make clinical decisions based on results of clinical trials, then it is imperative that the patient would have been suitable for entry into that clinical trial. Thus, as always, additional factors remain important when one has to determine the appropriate therapy for any single patient. These factors include persistent symptoms despite aggressive therapy, objective evidence of end points such as recurrent myocardial ischemia, life-threatening arrhythmias, ventricular dsyfunction, and presence of absence of factors that would suggest one therapy or another-for example, coronary artery spasm. If the patient has coronary artery disease, the location and severity of the coronary artery stenosis certainly influences decisions about medical or revascularization therapy, as do the confidence and enthusiasm of the surgeon and the desires of the patient.