Diagnosis and management of patients with unstable angina

Contemporary diagnosis and management of unstable angina

Unstable angina (UA) is one of the acute coronary syndromes, a group of conditions that also includes non-ST elevation myocardial infarction (MI) and ST elevation MI. The underlying pathogenic substrate of all these entities is the unstable coronary plaque with an overlying intracoronary thrombus. Initial management for the patient with suspected UA includes a resting electrocardiogram and oral administration of aspirin. ST-segment elevation indicates acute MI with the need for urgent reperfusion therapy. Patients without ST-segment elevation commonly have a mixture of UA and non-ST elevation MI; initial management is similar with assessment of near-term risk of MI or death as the next step. Features of UA indicating high risk include persistent ST-segment depression, persistent ischemic pain, elevated troponin level, or features of heart failure. Such patients undergo intensive medical therapy with heparin (unfractionated or low-molecular-weight), beta-blockade, and IIb/IIa antiplatelet agents, usually followed by coronary angiography and percutaneous intervention. The timing of intervention depends on the patient's response to therapy. Intermediate- or low-risk patients (including those presenting to the emergency department) can be managed with a chest pain unit strategy, and those with normal results on serial electrocardiograms, cardiac marker studies, and functional testing can be safely discharged home. Others are admitted for elective angiography, intensive medical therapy, or both. Assessment of coronary risk factors and their modification is an important component of long-term therapy for both high-risk and low-risk patients with UA, as well as those determined to have had non-ST elevation MI.

Long-term effects of diltiazem and verapamil on mortality and cardiac events in non-Q-wave acute myocardial infarction without pulmonary congestion: post hoc subset analysis of the multicenter diltiazem postinfarction trial and the second danish verapamil infarction trial studies

The main objective of this retrospective analysis was to evaluate the long-term effect of the heart rate-lowering calcium antagonists verapamil and diltiazem on the incidence of combined cardiac events and all-cause mortality in patients who had experienced a non-Q-wave acute myocardial infarction (AMI), but who did not also have pulmonary congestion. In addition, factors having an independent association with these 2 outcomes were identified. Of 817 non-Q-wave patients, 81 (9.9%) died during 12 to 52 months of follow-up. The unadjusted mortality rate was 42% lower in patients randomized to calcium antagonist therapy than placebo (7.2% vs 12.4%, p = 0.010). Non-Q-wave patients who died during follow-up were older than patients who survived (62 vs 58 years, p = 0.001). Other factors found to have an independent association with all-cause mortality included diuretic use (RR 2.79), diabetes mellitus (RR 2.86), and New York Heart Association class >I (RR 1.73). The covariate adjusted all-cause mortality risk ratio associated with randomization to calcium antagonist therapy was 0.65 (95% confidence interval [0.40 to 1.05, p = 0.079]). Overall, 153 patients (18.7%) died or had nonfatal reinfarction. The unadjusted combined event rate was 31% lower in patients randomized to calcium antagonist therapy than to placebo (15.2% vs 21.9%, p <0.006). Factors found to have an independent association with cardiac events included age, diabetes (RR 2.82), diuretic use (RR 2.04), and previous AMI (RR 1. 71). In addition, randomization to the calcium antagonist group had a significant independent association with reduced cardiac events (p = 0.031). The covariate adjusted event rate RR associated with randomization to the calcium antagonist group was 0.69 (95% confidence interval [0.49 to 0.97]). In conclusion, the heart rate-lowering calcium antagonists diltiazem and verapamil may play an important role in reducing long-term mortality and reinfarction in non-Q-wave AMI without pulmonary congestion.