Frequency of silent myocardial ischemia following coronary stenting

Reviewing myocardial silent ischemia: specific patient subgroups

Silent myocardial ischemia (SMI) is a relatively common, yet poorly understood, clinical entity. The most accurate means of detecting SMI and the precise treatment endpoints remain unclear. However, the presence of SMI correlates with the likelihood of future adverse cardiac events. Evidence suggests that patients at high risk of severe cardiac ischemia, even with the absence of symptoms, derive the greatest benefit from an aggressive diagnostic and therapeutic approach. This paper is giving a detailed review of SMI in regards to specific patient subgroups, i.e. populations with diabetes mellitus, hypertension, elderly patients, post-revascularization patients, women, the suggested screening procedures for each subgroup, as well as the emersion of new markers for the selection of high-risk patients for screening.

Continuous 12-lead electrocardiographic ST monitoring and long-term prognosis after successful coronary stenting

BACKGROUND

The possible long-term prognostic value of transient ST ischemic episodes detected by continuous multilead electrocardiographic (ECG) monitoring after successful coronary stenting (CS) has not been thoroughly investigated.

METHODS

A total of 739 consecutive patients, who underwent a 24-hour, continuous 12-lead electrocardiographic (ECG) ST monitoring in the first day after successful CS, were studied. An ST ischemic episode was defined as a transient ST shift (depression or elevation) in any lead of > or = 0.10 mV compared with the reference ECG lasting for > or = 1 minute.

RESULTS

The incidence of the composite of death, nonfatal myocardial infarction, and recurrent angina by the first year was 28.7%. Patients with > or = 3 (defined by receiver operating characteristics analysis) ST ischemic episodes, detected by continuous 12-lead ECG ST monitoring, were at significantly higher risk for the 1-year composite primary end point than those with either 1 and 2 (52.7% vs 25.7%, hazard ratio [HR] 2.1, 95% CI 1.4-3.7, P < .001) or no (52.7% vs 25%, HR 2.2, 95% CI 1.2-2.9, P < .001) ST ischemic episodes. By multivariate Cox regression analysis, the occurrence of > or = 3 ST ischemic episodes in the first postprocedural day was independently associated with a significant increased risk of the 1-year composite primary end point (HR 1.9, 95% CI 1.4-3.9, P = .002).

CONCLUSIONS

The present study suggests that continuous 12-lead ECG ST monitoring in the first day after successful CS may serve as an affordable tool for the identification of patients with an increased risk of fatal or nonfatal ischemic complication during the first year after the procedure.

Contemporary management of silent ischemia: the role of ambulatory monitoring

Silent ischemia is highly prevalent among patients with ischemic heart disease and is associated with a poor prognosis in moderate/high risk outpatients who either exhibit exercise- or pharmacological-induced myocardial ischemia, or in those patients who demonstrate silent ischemia following an acute coronary syndrome. Pharmacotherapy, including beta-blockers, angiotensin-converting enzyme inhibitors, statins, calcium channel antagonists and antiplatelet agents, have all demonstrated a reduction in silent ischemia and an improvement in cardiac prognosis. The management of patients with ischemic heart disease is currently based on patients' report of anginal symptoms: documentation of silent ischemia, usually using ambulatory electrocardiography, is not incorporated into the routine management of coronary artery disease. Yet studies comparing ambulatory electrocardiography with exercise testing have shown these tests to be complementary. We review the evidence concerning the prognostic value of ambulatory electrocardiography for monitoring silent ischemia and the prognostic value of attenuating silent ischemia. Mitigation of silent ischemia improves cardiac prognosis and ambulatory electrocardiographic monitoring before and after treatment of silent ischemia can play a valuable role in the management of coronary artery disease.

Induced ischemia detected by dobutamine stress echocardiography in coronary heart disease patients after myocardial re-vascularization. Experience in a District General Hospital

Most episodes of myocardial ischemia in patients with known coronary artery disease (CHD) are asymptomatic. Silent myocardial ischemia (SMI) is an important predictor of adverse outcome in patients with proven coronary artery disease. beta-blockers are effective in suppressing ischemia, and improve clinical outcome in patients with coronary artery disease. At present, it is common practice to stop treatment with beta-blockers in clinically asymptomatic patients after coronary artery bypass graft (CABG) and/or myocardial re-vascularization (PTCA/Stent), although the possible presence of SMI/inducible ischemia after myocardial re-vascularization is not known. We examined 56 asymptomatic CHD patients after coronary artery bypass graft (n=36), percutaneous coronary angioplasty PTCA/stent (n=15), or both (n=5); therapy with beta-blockers was stopped in all of them after myocardial revascularization. All these patients underwent a dobutamine stress echocardiography test (DSE test). The DSE test was proposed to these asymptomatic CHD patients to investigate the possible presence of SMI/inducible ischemia after myocardial re-vascularization. All patients had history of myocardial infarction or evidence of mildly impaired left ventricular function at rest as assessed by cardiac catheterization. Abnormal DSE studies occurred in eight of the 56 patients (14%; 95% C.I.: 6-26%). Therapeutic approaches specifically targeted at reducing total ischaemic burden include pharmacologic therapy and myocardial revascularization. On the basis of these data, it can be concluded that asymptomatic CHD patients after myocardial re-vascularization must be re-evaluated to rule out SMI/inducible ischemia that can be treated (e.g. with beta-blockers) reducing cardiovascular morbidity and mortality.