"Traditional" medical therapy for unstable angina. How important? How to use?

Long term risk stratification of patients with acute coronary syndromes: characteristics of troponin T testing and continuous ST segment monitoring

OBJECTIVE

To examine the long term prognostic characteristics of troponin T testing and continuous multi-lead ST segment monitoring in combination with clinical and 12 lead ECG risk indicators in patients with acute coronary syndromes (ACS).

PATIENTS AND DESIGN

Patients with suspected ACS (n = 213) were studied. Troponin T was analysed in blood samples collected during the first 12 hours after admission. Continuous vectorcardiography ST segment monitoring was performed for 24 hours and the number of ST vector magnitude episodes was registered. Patients were followed up for a median of 28 months. The end point was a composite of cardiac death and acute myocardial infarction.

RESULTS

Thirty eight (18%) patients reached the composite end point. The median (interquartile range) time from study inclusion to the time of the composite end point was longer for patients predicted to be at risk by troponin T testing (n = 27) than for those predicted to be at risk by ST segment monitoring (n = 20) (8.4 (0.2-15) months v 0.3 (0.1-4.3) months, p = 0.04). Significant univariate predictors of the composite end point were age > or = 65 years, diabetes, previous myocardial infarction, congestive heart failure, use of beta blockers or diuretics at admission, 12 lead ECG ST segment depression at admission, troponin T concentration > or = 0.10 microg/l, and > or = 1 ST vector magnitude episodes. Age > or = 65 years, previous myocardial infarction, and troponin T concentration > or = 0.10 microg/l provided independent prognostic information after multivariate analysis of potential risk variables. The prognostic value of transient ischaemic episodes in ACS seems to be confined to the short term.

CONCLUSIONS

Both biochemical and continuous ECG markers reflect an increased risk for patients with ACS; however, the methods exhibit different temporal risk characteristics.

Medical therapy of unstable angina and non-Q-wave myocardial infarction

Management of acute coronary syndromes has been the focus of increased interest in recent years. This has come about with the recognition that the majority of patients who present to the hospital with chest pain have unstable angina or non-Q-wave myocardial infarction (MI). Further, sensitive biochemical markers of myocardial necrosis, such as troponin and creatine kinase, have improved early diagnosis. Markers of inflammation such as C-reactive protein (CRP), although not in wide clinical practice, may provide an early and important marker of prognosis. The current approach to management of acute coronary syndromes is careful risk stratification so as to select appropriate medical therapies and to guide the clinician to appropriate interventions such as angiography or percutaneous coronary intervention (PCI). Established therapies such as aspirin, heparin, intravenous nitrates, and, in selected patients, beta blockers or calcium antagonists, are being used concomitantly with, or are being supplanted by, newer therapies such as low-molecular-weight heparins and glycoprotein IIb/IIIa inhibitors. The role of hydroxymethyl glutaryl coenzyme A reductase inhibitors (statins) in patients with acute coronary syndromes is being investigated and shows promise.