The health care burden of unstable angina

Unstable Angina as a Component of Primary Composite Endpoints in Clinical Cardiovascular Trials: Pros and Cons

Background Unstable angina (UA) is a component of acute coronary syndrome that is only occasionally included in primary composite endpoints in clinical cardiovascular trials. The aim of this paper is to elucidate the potential benefits and disadvantages of including UA in such contexts. Summary UA comprises <10% of patients with acute coronary syndromes in contemporary settings. Based on the pathophysiological similarities, it is ideal as a part of a composite endpoint along with myocardial infarction (MI). By adding UA as a component of a primary composite endpoint, the number of events and feasibility of the trial should increase, thus decreasing size and costs of trials. Furthermore, UA has both economic and quality of life implications on a societal and an individual level. However, there are important challenges associated with the use of UA as an endpoint. With the introduction of high-sensitivity troponins, the number of individuals diagnosed with UA has decreased to rather low levels, with a reciprocal increase in the number of MI. In addition, UA is particularly challenging to define given the subjective assessment of the index symptoms, rendering a high risk of bias. To minimize bias, strict criteria are warranted, and events should be adjudicated by a blinded endpoint adjudication committee. Key messages UA should only be chosen as a component of a primary composite endpoint in cardiovascular trials after thoroughly evaluating the pros and cons. If it is chosen to include UA, appropriate precautions should be taken to minimize possible bias.

Changes in, and predictors of, quality of life among patients with unstable angina after percutaneous coronary intervention

RATIONALE, AIMS AND OBJECTIVES

Changes in, and predictors of, quality of life (QoL) among unstable angina patients are informative for both clinical and public health practice. However, there is little research on this topic, especially in health care settings with limited resources. This study aims to detect changes in QoL and its associated factors among patients with unstable angina after percutaneous coronary intervention.

METHODS

A longitudinal design was conducted with two repeated rounds of measurements, 1 and 3 months after intervention, using the generic SF-36 questionnaire, in 120 patients from Vietnam National Heart Institute. A linear mixed-effects model was used to assess changes in patient QoL over time while adjusting for other covariates.

RESULTS

Only two out of eight QoL subscales (social functioning and emotional well-being) declined after 1 month, but these tended to rise again after 3 months, while scores of all other QoL subscales increased. Adjusting for covariates, QoL increased slightly after 1 month of intervention (β = 0.65, 95%CI = -0.86 to 2.16) but improved by almost six QoL points after 3 months (β = 5.99, 95%CI = 4.48 to 7.50). Four confounders significantly associated with a decline in QoL were older age, being retired, living in rural areas, and having abnormal troponin level.

CONCLUSION

QoL of the patients with unstable angina improves significantly 3 months after intervention, rather than after 1 month. More attention should be given to patients, who are old, retired, live in rural areas and have abnormal troponin level.

Platelet glycoprotein IIb/IIIa inhibitors for acute coronary syndromes: initiate treatment early or wait for the catheterization laboratory?

Treatment of patients with acute coronary syndromes (ACS) incorporates several approaches to reverse or mitigate the thrombus, which invariably is at the center of the pathophysiologic process of ACS. Pharmacologic and mechanical strategies are designed to prevent death, reduce myocardial necrosis, and stabilize the plaque to prevent later sequelae. Conventional antithrombotic therapy includes antiplatelet and anticoagulant drugs. Medications that inhibit the platelet glycoprotein IIb/IIIa receptor have been shown to be especially efficacious in the treatment of ACS. Recent clinical trials have validated a strategy of aggressive revascularization, particularly catheter-based percutaneous procedures. This review summarizes new trial results and provides a working algorithm for care of the patient with ACS.