A Classification of Unstable Angina Revisited

Abstract

Abstract-Unstable angina is a critical phase of coronary heart disease with widely variable symptoms and prognosis. A decade ago, a classification of unstable angina based on clinical symptoms was introduced. This system was then validated by prospective clinical studies to correlate with the prognosis and was linked to angiographic and histological findings. It has been used to categorize patients in many large clinical trials. In recent years, the pathophysiological roles of platelet activation and inflammation in unstable angina have been elucidated. Subsequently, improved markers of myocardial injury, acute-phase proteins, and hemostatic markers that may be associated with clinical outcomes have been identified. Particularly, cardiac-specific troponin T and troponin I have been shown to represent the best predictors of early risk in patients with angina at rest. Accordingly, it is suggested that the original classification be extended by subclassifying one large group of unstable angina patients, ie, those with angina at rest within the past 48 hours (class IIIB), into troponin-positive (T pos ) and troponin-negative (T neg ) patients. The 30-days risk for death and myocardial infarction is considered to be up to 20% in class IIIB-T pos but Ͻ2% in class IIIB-T neg patients. Initial results suggest that troponins may function as surrogate markers for thrombus formation and can effectively guide therapy with glycoprotein IIb/IIIa antagonists or low-molecular-weight heparins. These observations provide additional impetus for adding the measurement of these markers to the clinical classification and represent a novel concept of treating these high-risk patients. (Circulation. 2000;102:118-122.)Key words: angina Ⅲ atherosclerosis Ⅲ coronary disease Ⅲ myocardial infarction Ⅲ prognosis I t has long been recognized that coronary artery disease comprises a wide spectrum of conditions, ranging from chronic stable angina to acute myocardial infarction. Unstable angina, in the middle of this spectrum is a heterogeneous syndrome with widely variable symptoms and prognosis. In 1989, a classification of unstable angina was introduced 1 ; this classification is based on the clinical history (accelerated exertional angina or rest pain, the timing of the latter in respect to presentation, and the clinical circumstances in which unstable angina developed), on the presence or absence of ECG changes, and on the intensity of anti-ischemic therapy.Although the development of this classification was based on clinical experience, it has been validated in a number of prospective studies. For example, Calvin et al 2 studied 393 patients with unstable angina and reported that a history of a myocardial infarction within 14 days (class C) and STsegment depression on the presenting ECG were both markers of increased risk. Miltenburg-van Zijl et al 3 classified 417 patients with unstable angina and followed them up for 6 months. Death or myocardial infarction occurred more frequently in those with recent rest pain (class III) and in postin...

A new simple risk score in patients with acute chest pain without existing known coronary disease

“…Of note, in this large first group of patients, the 1% coronary event rate at followup is even lower than the risk reported in the same "lowrisk" patients in a previous study [1,2]. Moreover, in the same very low-risk group, the low cost and worldwide availability of ETT did not substantially increase the ability in ruling out future coronary events as compared with the prediction rule (1.7% vs 3.6% event rate of the pretest).…”

“…Patients with chest pain (CP) and nondiagnostic initial work-up, including electrocardiogram (ECGs) and serial troponins, and without existing known coronary artery disease are currently considered at low risk of short-term coronary events (b2% of death and/or myocardial infarction) [1,2]. However, in that large and heterogeneous population with a mean low prevalence of coronary disease, diagnosis of acute coronary syndrome still represents a challenge.…”

Risk scores prognostic implementation in patients with chest pain and nondiagnostic electrocardiograms

“…Indeed, the presence of high CP score has a high factor in cumulated risk score [13]. Patients with FPR low score showed a very low probability of future coronary events, less than 1%, data which are even lower than the risk reported in low-risk patients considered in previous studies [3,19].…”

“…All patients underwent a first-line, 6-hour workup including clinical evaluation, serial ECGs, and serial troponins [2,3,[17][18][19]. Enrolled patients with CP were categorized by all the previously validated risk scores (Grace, Pursuit, TIMI, Goldman, Sanchis, and FPR) [6][7][8][9][10][11][12][13].…”

“…In addition, some prediction rules are based on clinical data, whereas others used only major risk factors for atherosclerosis [14][15][16]. Therefore, which risk score to be used remains a challenge because no standardized prediction rule is yet available for stratification of patients with low-risk CP [3,[17][18][19].…”