Asymptomatic Cardiac Ischemia Pilot (ACIP) study: impact of anti-ischemia therapy on 12-week rest electrocardiogram and exercise test outcomes. The ACIP Investigators

Efficacy of a device to narrow the coronary sinus in refractory angina

BACKGROUND

Many patients with coronary artery disease who are not candidates for revascularization have refractory angina despite standard medical therapy. The balloon-expandable, stainless steel, hourglass-shaped, coronary-sinus reducing device creates a focal narrowing and increases pressure in the coronary sinus, thus redistributing blood into ischemic myocardium.

METHODS

We randomly assigned 104 patients with Canadian Cardiovascular Society (CCS) class III or IV angina (on a scale from I to IV, with higher classes indicating greater limitations on physical activity owing to angina) and myocardial ischemia, who were not candidates for revascularization, to implantation of the device (treatment group) or to a sham procedure (control group). The primary end point was the proportion of patients with an improvement of at least two CCS angina classes at 6 months.

RESULTS

A total of 35% of the patients in the treatment group (18 of 52 patients), as compared with 15% of those in the control group (8 of 52), had an improvement of at least two CCS angina classes at 6 months (P=0.02). The device was also associated with improvement of at least one CCS angina class in 71% of the patients in the treatment group (37 of 52 patients), as compared with 42% of those in the control group (22 of 52) (P=0.003). Quality of life as assessed with the use of the Seattle Angina Questionnaire was significantly improved in the treatment group, as compared with the control group (improvement on a 100-point scale, 17.6 vs. 7.6 points; P=0.03). There were no significant between-group differences in improvement in exercise time or in the mean change in the wall-motion index as assessed by means of dobutamine echocardiography. At 6 months, 1 patient in the treatment group had had a myocardial infarction; in the control group, 1 patient had died and 3 had had a myocardial infarction.

CONCLUSIONS

In this small clinical trial, implantation of the coronary-sinus reducing device was associated with significant improvement in symptoms and quality of life in patients with refractory angina who were not candidates for revascularization. (Funded by Neovasc; COSIRA ClinicalTrials.gov number, NCT01205893.).

Evaluation of suspected ischemic heart disease in symptomatic women

There is a wealth of evidence about the role of a variety of diagnostic testing modalities to define coronary artery disease (CAD) risk in women presenting for evaluation of suspected myocardial ischemia. The exercise electrocardiogram (ECG) is the core index procedure, which can define risk in women capable of performing maximal exercise. Stress imaging, using echocardiography or myocardial perfusion single-photon emission computed tomography/positron emission tomography, is useful for symptomatic women with an abnormal resting ECG or for those who are functionally disabled. For women with low-risk stress imaging findings, there is a very low risk of CAD events, usually < 1%. There is a gradient relationship between the extent and severity of inducible abnormalities and CAD event risk. Women at high risk are those defined as having moderate to severely abnormal wall motion or abnormal perfusion imaging findings. In addition to stress imaging, the evidence of the relationship between CAD extent and severity and prognosis has been clearly defined with coronary computed tomographic angiography. In women, prognosis for those with mild but nonobstructive CAD is higher when compared with those without any CAD. The current evidence base clearly supports that women presenting with chest pain can benefit from one of the commonly applied diagnostic testing modalities.

A phase II, sham-controlled, double-blinded study testing the safety and efficacy of the coronary sinus reducer in patients with refractory angina: study protocol for a randomized controlled trial

Background

A growing population of patients lives with severe coronary artery disease not amenable to coronary revascularization and with refractory angina despite optimal medical therapy. Percutaneous reduction of the coronary sinus is an emerging treatment for myocardial ischemia that increases coronary sinus pressure to promote a transcollateral redistribution of coronary artery in-flow from nonischemic to ischemic subendocardial territories. A first-in-man study has demonstrated that the percutaneous reduction of the coronary sinus can be performed safely in such patients. The COSIRA trial seeks to assess whether a percutaneous reduction of the coronary sinus can improve the symptoms of refractory angina in patients with limited revascularization options.

Methods/Design

The COSIRA trial is a phase II double-blind, sham-controlled, randomized parallel trial comparing the percutaneously implanted coronary sinus Reducer (Neovasc Inc, Richmond, BC, Canada) to a sham implantation in 124 patients enrolled in Canada, Belgium, England, Scotland, Sweden and Denmark. All patients need to have stable Canadian Cardiovascular Society (CCS) class III or IV angina despite optimal medical therapy, with evidence of reversible ischemia related to disease in the left coronary artery, and a left ventricular ejection fraction >25%. Participants experiencing an improvement in their angina ≥2 CCS classes six months after the randomization will meet the primary efficacy endpoint. The secondary objective of this trial is to test whether coronary sinus Reducer implantation will improve left ventricular ischemia, as measured by the improvement in dobutamine echocardiogram wall motion score index and in time to 1 mm ST-segment depression from baseline to six-month post-implantation.

Discussion

Based on previous observations, the COSIRA is expected to provide a significant positive result or an informative null result upon which rational development decisions can be based. Patient safety is a central concern and extensive monitoring should allow an appropriate investigation of the safety related to the coronary sinus Reducer.

Trial registration

ClinicalTrials.gov identifier - NCT01205893.

A randomized, placebo-controlled study of the effects of telcagepant on exercise time in patients with stable angina

Telcagepant is a calcitonin gene-related peptide (CGRP) receptor antagonist being evaluated for acute migraine treatment. CGRP is a potent vasodilator that is elevated after myocardial infarction, and it delays ischemia during treadmill exercise. We tested the hypothesis that CGRP receptor antagonism does not reduce treadmill exercise time (TET). The effects of supratherapeutic doses of telcagepant on TET were assessed in a double-blind, randomized, placebo-controlled, two-period, crossover study in patients with stable angina and reproducible exercise-induced angina. Patients received telcagepant (600 mg, n = 46; and 900 mg, n = 14) or placebo and performed treadmill exercise at T(max) (2.5 h after the dose). The hypothesis that telcagepant does not reduce TET was supported if the lower bound of the two-sided 90% confidence interval (CI) for the mean treatment difference (telcagepant-placebo) in TET was more than -60 s. There were no significant between-treatment differences in TET (mean treatment difference: -6.90 (90% CI: -17.66, 3.86) seconds), maximum exercise heart rate, or time to 1-mm ST-segment depression using pooled data or with stratification for dose.

Silent myocardial ischemia

Although much progress has been made in reducing mortality from ischemic cardiovascular disease, this condition remains the leading cause of death throughout the world. This might in part be due to the fact that over half of patients have a catastrophic event (heart attack or sudden death) as their initial manifestation of coronary disease. Contributing to this statistic is the observation that the majority of myocardial ischemic episodes are silent, indicating an inability or failure to sense ischemic damage or stress on the heart. This review examines the clinical characteristics of silent myocardial ischemia, and explores mechanisms involved in the generation of angina pectoris. Possible mechanisms for the more common manifestation of injurious reductions in coronary flow; namely, silent ischemia, are also explored. A new theory for the mechanism of silent ischemia is proposed. Finally, the prognostic importance of silent ischemia and potential future directions for research are discussed.

Differences between male and female patients with regard to baseline demographics and clinical outcomes in the Asymptomatic Cardiac Ischemia Pilot (ACIP) Trial

BACKGROUND

Coronary artery disease (CAD) is a common problem in men and women; however, men and women with similar clinical presentations of myocardial ischemia may receive different revascularization treatments.

HYPOTHESIS

Using the data base of the Asymptomatic Cardiac Ischemia Pilot (ACIP) trial, this study was undertaken to compare by gender the baseline demographic data and the clinical outcome results in patients randomized to various treatments in the ACIP study.

METHODS

This randomized trial compared three treatment regimens [pharmacologic management of angina, pharmacologic management of angina and ambulatory electrocardiographic (ECG) evidence of ischemia, and revascularization--that is, angioplasty and coronary artery bypass surgery], in patients with known CAD, positive stress ECG tests, and ECG evidence of ischemia during 48 h ambulatory monitoring. In all, 558 patients were randomized, 79 of whom were women (mean age: men 61.6 years, women 60.6 years) Ambulatory ECG evidence of ischemia, clinical events, that is, death, myocardial infarction, hospital admission for coronary events, and exercise performance were monitored.

RESULTS

Although of the same age as men at baseline, women had a higher prevalence of hypertension and diabetes. Women had less severe CAD by angiography and higher left ventricular ejection fractions. Men had longer exercise tolerance times on the treadmill. However, men and women had similar numbers and duration of ambulatory ECG ischemic abnormalities. Regarding revascularization, men more commonly underwent coronary artery bypass surgery (p = 0.025) while women underwent percutaneous transluminal coronary angioplasty more frequently (p = 0.10). Clinical outcomes were comparable in men and women, although the numbers of events were relatively small.

CONCLUSIONS

Men and women of comparable age manifest CAD with similar ischemic ECG abnormalities seen on both exercise tolerance and ambulatory ECG examinations. In ACIP, women tended to have more risk factors for CAD and less severity in anatomical disease, which may explain why women are less likely than men to have coronary bypass surgery.

Trimetazidine added to combined hemodynamic antianginal therapy in patients with type 2 diabetes: a randomized crossover trial

BACKGROUND

In nondiabetic patients with stable angina, combined treatment with hemodynamic agents and trimetazidine is well-tolerated and effective in controlling ischemia. This study aims to evaluate the antiischemic and metabolic effects of trimetazidine in patients with type 2 diabetes mellitus, not eligible for revascularization, who remained symptomatic despite the use of at least 2 antianginal agents.

METHODS

A randomized, double-blind, crossover clinical trial was used. Ten patients were randomized to receive trimetazidine (20 mg, 3 times a day) or placebo for 6-week periods. At baseline and at the end of each 6-week intervention period, clinical and biochemical evaluations, exercise testing, 24-hour ambulatory blood pressure, and Holter monitoring were performed.

RESULTS

During trimetazidine therapy, patients had significant improvement on angina functional class (P < .05), with decrease in the number of weekly angina episodes (1.5 +/- 0.8 vs 0.4 +/- 0.7, P < .01), and in sublingual nitrate doses (1.4 +/- 0.7 mg vs 0.1 +/- 0.3 mg, P < .001). Time to 1-mm ST-segment depression during exercise test was increased after trimetazidine use (229 +/- 126 seconds at baseline, 276 +/- 101 seconds after placebo, and 348 +/- 145 seconds after trimetazidine, P < .001). No differences were observed between treatment periods on mean 24-hour blood pressure, heart rate, and rate-pressure product evaluated concomitantly with ambulatory blood pressure and Holter monitoring. Glycemic and lipid profiles were similar after trimetazidine and placebo use.

CONCLUSIONS

In patients with diabetes who remain symptomatic, the addition of trimetazidine improves symptoms and exercise responses without hemodynamic or metabolic changes. The present data suggest that trimetazidine may be an effective adjunct therapy for these patients, but further investigation is needed to confirm these findings.

Long-term continuous external electrocardiographic recording: a review

Ambulatory electrocardiographic (AECG) monitoring is an essential tool in the diagnostic evaluation of patients with cardiac arrhythmias. Recent advances in solid-state technology have improved the quality of the ECG signals and new dedicated algorithms have expanded the clinical application of software-based AECG analysis systems. These advances, in addition to the availability of inexpensive large storage capacities, and very long-term continuous high-quality AECG monitoring, have opened new potential uses for AECG. New digital recorders have the capability of multichannel simultaneous recordings (from 3 to 12 leads) and for telemetred signal transduction. These possibilities will expand the traditional uses of AECG for arrhythmia detection, as arrhythmia monitoring to assess drug and device efficacies has been further defined by new studies. The analysis of transient ST-segment deviation still remains controversial, but considerably more data are now available, especially about the prognostic value of detecting asymptomatic ischaemia. Heart rate variability analysis has shown promise for predicting mortality rates in cardiac patients at high risk. We review recent advances in this field of non-invasive cardiac testing.

Antianginal efficacy of omapatrilat in patients with chronic angina pectoris

Angiotensin-converting enzyme inhibition is not an effective antianginal therapy. Experimental data suggest that broader vasopeptidase inhibition may decrease the magnitude of demand-induced myocardial ischemia. A randomized, double-blind, placebo controlled parallel study evaluated omapatrilat, an inhibitor of angiotensin-converting enzyme and neutral endopeptidase. The primary objective was to compare maximum duration of exercise at peak plasma concentrations. Exercise treadmill studies were performed in 348 patients who had chronic angina at baseline and after 4 weeks of therapy with 80 mg/day omapatrilat or placebo. Safety data were collected and reported for all patients. Treadmill exercise duration at peak was significantly prolonged in the omapatrilat group compared with the placebo group (76.6 +/- 84.2 vs 28.7 +/- 82.2 seconds difference from baseline, p <0.001). Similar statistically significant increases were seen in time to onset of level III/IV angina and time to onset of >/=0.1-mV ST-segment depression (p <0.001). The significant improvements in exercise duration and measurements of myocardial ischemia were not sustained 20 to 28 hours after dosing. Omapatrilat was generally well tolerated in this predominantly normotensive population. The incidence of serious adverse events was 5.2% in the 2 groups. Thus, omapatrilat, an investigational vasopeptidase inhibitor, is effective in prolonging exercise duration and parameters of demand-induced myocardial ischemia in patients who have chronic angina at peak concentrations. The data confirm the proof of principle that broader vasopeptidase inhibition beyond angiotensin-converting enzyme inhibition is required to alleviate symptoms of chronic angina.

Exercise treadmill testing using a modified exercise protocol in women with suspected myocardial ischemia: findings from the National Heart, Lung and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation (WISE)

BACKGROUND

Exercise testing, a major diagnostic modality in individuals with suspected coronary artery disease (CAD), has in general demonstrated less overall diagnostic accuracy in women compared to men. As part of the WISE, a modified protocol was examined with the intention of improving reliability of exercise testing.

METHODS

Criteria for entry in the WISE study include clinically indicated coronary angiography. Exercise testing was performed using a protocol modified to be more appropriate for women. The study population consisted of 96 women, mean age of 55.8 y (range 34-77), who completed exercise treadmill test (ETT). Most (78%) were postmenopausal; 96% had >or =2 risk factors for CAD.

RESULTS

By core laboratory angiography, 29/96 women had stenosis > or =50% in at least one coronary artery. Of these 29 women, 9 had abnormal ETT, yielding overall sensitivity of 31%. The remaining 20 women had normal (12/29, 41%) or nondiagnostic (8/29, 28%) studies. Among the 67 women with minimal or no coronary stenosis, 35 had no ischemic ST-segment changes during ETT, yielding overall specificity of 52%. Analysis with exclusion of women with nondiagnostic studies yielded sensitivity and specificity of 43% and 66%, respectively. The presence of coronary artery stenosis and inability to perform ETT, but not results of testing, predicted the outcomes of myocardial infarction, heart failure, and death.

CONCLUSIONS

Exercise treadmill test appears to be of limited diagnostic value in women with suspected myocardial ischemia referred for coronary angiography. Sensitivity and specificity remain poor even with modified exercise protocol and core laboratory angiographic analysis. These findings merit consideration in view of current guidelines that recommend exercise testing in women with suspected CAD.

Comparison of effects of nisoldipine-extended release and amlodipine in patients with systemic hypertension and chronic stable angina pectoris

The efficacy and safety of nisoldipine-extended release (ER) and amlodipine were compared in a 6-week multicenter, randomized, double-blind, double-dummy, parallel group, titration-to-effect trial in patients with stage 1 to 2 systemic hypertension (90 to 109 mm Hg diastolic blood pressure [BP]) and chronic stable angina pectoris. After a 3-week placebo run-in period, patients (n = 120) were randomly assigned to active treatment with either nisoldipine-ER (20 to 40 mg) or amlodipine (5 to 10 mg) once daily, titrated as necessary after 2 weeks to achieve diastolic BP <90 mm Hg. After 6 weeks, the mean reduction in systolic/diastolic BP from baseline was 15/13 mm Hg with nisoldipine-ER and 13/11 mm Hg with amlodipine (p = NS/p = NS). Both drugs resulted in similar BP responder rates (diastolic BP <90 mm Hg in 87% of patients who received nisoldipine-ER and 78% of patients on amlodipine, p = NS) and anti-ischemic responder rates (increasing exercise time >20% in 20% and 27%, respectively [p = NS], and increasing exercise time >60 seconds in 32% and 29% of patients, respectively [p = NS]. Also, after 6 weeks of active therapy, there was a similar mean increase in total exercise duration (23 seconds in the nisoldipine-ER group and 21 seconds in the amlodipine group, p = NS). Neither drug increased heart rate and both decreased frequency of anginal episodes. Adverse events were infrequent, and typically were vasodilator-related effects (including headache and peripheral edema) that occurred with somewhat higher incidence in the nisoldipine-ER group. Thus, nisoldipine-ER and amlodipine provided comparable antihypertensive and anti-ischemic efficacy, and both were generally well tolerated.

Randomized trial of a medical food for the dietary management of chronic, stable angina

OBJECTIVES

We determined the electrocardiographic, vascular and clinical effects of a medical food bar enriched with L-arginine and a combination of other nutrients known to enhance endothelium-derived nitric oxide (NO) in patients with stable angina.

BACKGROUND

Enhancement of vascular NO by supplementation with L-arginine and other nutrients has been shown to have clinical benefits in patients with angina secondary to atherosclerotic coronary artery disease (CAD). However, the amounts and combinations of these nutrients required to achieve a clinical effect make traditional delivery by capsules and pills less suitable than alternative delivery methods such as a specially formulated nutrition bar.

METHODS

Thirty-six stable outpatients with CAD and class II or III angina participated in a randomized, double-blind, placebo-controlled, crossover trial with two treatment periods each of two weeks' duration (two active bars or two placebo bars per day). Flow-mediated brachial artery dilation was measured by ultrasound. Electrocardiographic measures of ischemia, exercise capacity and angina onset time were measured by treadmill exercise testing and by Holter monitor during routine daily activities. Quality of life was assessed by SF-36 and Seattle Angina Questionnaires and by diary.

RESULTS

The medical food improved flow-mediated vasodilation (from 5.5 +/- 4.5 to 8.0 +/- 4.9, p = 0.004), treadmill exercise time (by 20% over placebo, p = 0.05) and quality-of-life scores (SF-36 summary score; 68 +/- 13 vs. 63 +/- 21 after placebo, p = 0.04, Seattle Angina Questionnaire summary score; 67 +/- 10 vs. 62 +/- 18, p = 0.04) without affecting electrocardiographic manifestations of ischemia or angina onset time.

CONCLUSIONS

These findings reveal that this arginine-rich medical food, when used as an adjunct to traditional therapy, improves vascular function, exercise capacity and aspects of quality of life in patients with stable angina.

Modification of high blood pressure after myocardial infarction

The treatment of high blood pressure (BP) after myocardial infarction is extremely important to decrease reinfarction and mortality. BP should be controlled more strictly in this high-risk hypertensive population. Recently, many clinical trials have demonstrated the benefits of lifestyle modification and antihypertensive agents, particularly beta-blockers and angiotensin-converting-enzyme inhibitors for the treatment of acute myocardial infarction. Treatment with these agents that modify BP may benefit even normotensive patients after a myocardial infarction, although the benefit is greater in hypertensives.

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.

[Significance of silent myocardial ischemia for identification and optimal therapy of patients with latent coronary heart disease. Is there a marker for prognostic indication for PTCA?]

Although percutaneous transluminal coronary angioplasty (PTCA) improves the symptomatic status and exercise capacity of patients with coronary artery disease and stale or unstable angina pectoris, a beneficial effect on long-term prognosis has not been convincingly demonstrated so far. In totally asymptomatic patients with coronary artery disease, however, decision to undertake PTCA is greatly influenced by prognostic considerations. Usually, detection of silent myocardial ischemia in non-invasive examinations (exercise stress testing, ambulatory electrocardiographic monitoring) precedes the angiographic diagnosis of coronary artery disease in these patients.

Coronary heart disease. Stable and unstable syndromes

CHD in the elderly population will continue to be a source of major concern because of the increasing costs entailed and uncertainties about how the widespread array of diagnostic and therapeutic interventions, often expensive and sometimes hazardous, should be applied. Financial, political, and health policy decisions will continue to occupy much attention, but it is likely that philosophic considerations about aging and death, both from the individual and the societal perspective, will be of paramount importance of deciding how the substantial resources available to the elderly will be used. Randomized, controlled trials are unlikely to play a major role in resolution of management dilemmas in the elderly because of the extraordinary heterogeneity in this population. Registries (databases) involving carefully prospectively collected key variables are likely to be a more effective approach. Critical characterization of complications of procedures, adverse drug reactions, and collection of follow-up data on functional status are among the critical questions, and these can be answered by registry studies. Algorithms and clinical rules developed in younger cohorts are not directly transferable to the elderly cardiovascular patients, further emphasizing the need for prospectively collected, syndrome-specific data. Treatments convincingly demonstrated to reduce mortality in absolute terms more in the elderly than in the young are underused. The heterogeneity of aging emphasizes the wide variability in patients' ability to withstand the stress of procedures and complications of disease and makes clear the need to consider physiologic reserve and biologic age rather than chronology. With better characterization of biologic age and physiologic reserve, more precise estimates of outcomes of therapies and interventions can be made, and patients can be given better information and with their families have more realistic expectations. Better-informed decisions will result. Biologic age will be multifactorial, involving cognitive, emotional, physical, and nutritional attributes as well as specific organ function (lung, kidney, liver) because no single feature can characterize the total elderly patient. The concept of competing risks among the cardiovascular disease being treated, comorbidity, risks of study, and life expectancy will evolve because even the most successful therapy will have limited effect on longevity in the very old. Although important research at the cellular and molecular level will characterize and provide better understanding of the aging process, it is not likely that this basic information will be immediately useful in the management of the large number of elderly patients with major cardiovascular disease. Preventive measures, including physical exercise, mental stimulation, avoidance of depression, good nutrition, and abstinence from tobacco use, are useful approaches to postpone or ameliorate the consequences of aging and allow patients to tolerate cardiovascular diseases better when they become manifest.

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.

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.

Role of beta blockade in the treatment of myocardial ischemia

A number of antianginal drugs and therapeutic strategies are now available for the treatment of patients with coronary artery disease (CAD) and myocardial ischemia. Of the available antianginal drugs, beta blockers appear to be most effective in suppressing myocardial ischemia. The superior anti-ischemic efficacy of beta blockers can be explained by their beneficial actions on hemodynamic parameters, vasomotion, and platelet function. Compared with other anti-ischemic drugs, beta blockers appear to be more efficacious in reducing the magnitude of myocardial ischemia during routine daily activities. In addition, the results of recent studies indicate that treatment with beta blockers not only suppresses myocardial ischemia, but also improves the clinical outcome in patients with CAD. These beneficial effects, along with the well-demonstrated cardioprotective effects of beta blockade in the postinfarction period, clearly suggest that this class of anti-ischemic drugs is an ideal therapeutic choice in most patients with CAD.

Revascularization of patients with coronary artery disease: the interventional cardiologist's perspective

In the majority of patients with chronic coronary artery disease, treatment is aimed at palliation or prolongation of disease-free intervals and consists of either pharmacologic therapy or coronary revascularization. As a result of continuous refinements and improvements in both surgical and catheter-based revascularization techniques, modalities, and adjunctive pharmacologic therapy, an increasing number of patients may benefit from coronary revascularization. This also engenders difficult choices for the physicians responsible for selecting the most appropriate treatment. To achieve and provide optimal patient care an open and principled discussion with all parties involved is mandatory and must be based on the integration of clinical experience and data from both basic and clinical research. The purpose of this article is to provide the interventional cardiologist's view on the treatment of patients with atherosclerotic coronary artery disease.

Association between angina pectoris and ischemic indexes during exercise testing and ambulatory monitoring

We examined the relation between anginal symptoms and ischemic indexes during ischemia on exercise testing and daily activities in 76 patients (59 men and 17 women, mean age 61.5 years) with documented coronary artery disease and exercise-induced ischemia. All patients underwent upright bicycle exercise testing and 48-hour ambulatory electrocardiographic monitoring (AECG). Angina was reported in 28 patients (37%) during exercise-induced ischemia. A total of 287 ischemic episodes were detected from 44 patients (58%) during AECG. There was a mean number of 7.4 episodes and a mean total duration of 75 min/48 hours. There were no differences in the prevalence and the magnitude of ambulatory ischemia between patients with and without angina during exercise testing. Among the 44 patients who had ischemia during both tests, 50% of patients with angina during exercise testing had symptomatic ischemia during AECG compared to 14% in patients with silent ischemia during exercise testing (p = 0.01). Ninety-two percent of ischemic episodes were preceded by an increase in heart rate (HR) of > 10 beats/min. There was a strong positive correlation (r = 0.70, p < 0.01) between HR at onset of 1 mm ST depression (ischemic threshold) during exercise testing and during AECG. We conclude that (1) patients with exercise-induced angina have significantly more symptoms during ambulatory ischemia, (2) ischemic threshold during exercise testing and daily life are positively correlated, and (3) our findings emphasize the role of increased myocardial oxygen demand in the development of ambulatory ischemia.