Appropriateness of diagnosis of unstable angina pectoris in patients referred for coronary arteriography.

BACKGROUND

A diagnosis of unstable angina pectoris (UAP) often carries with it a decision to catheterize the patient promptly. However, UAP remains a clinical diagnosis, based mostly on a patient's clinical history and electrocardiogram (ECG) findings.

OBJECTIVE

To evaluate whether the diagnosis of UAP is overused in patients referred for coronary arteriography.

METHODS

Ninety-six patients with a diagnosis of UAP who were referred for invasive studies were re-examined clinically before catheterization. Coronarography was independently reviewed for correlation with clinical findings.

RESULTS

Based on the patient's history and ECG changes, UAP was classified by two independent cardiologists as 'very likely' in 58% and 49%, 'possible' in 19% and 30%, and of 'low probability' in 23% and 21%, respectively. Patients with 'very likely' UAP had a high incidence of significant coronary lesions (87% and 96% for each cardiologist) and complex lesions by angiography (41% and 49%, respectively). Patients with a diagnosis of 'low probability' UAP had a low incidence of significant coronary lesions (55% for each cardiologist) and a very low incidence of complex angiographic lesions (5% for each cardiologist). Patients with 'possible' UAP had intermediate results.

CONCLUSION

Because of a presumptive diagnosis of UAP, approximately 22% of all patients referred for coronarography have no clinical and/or ECG evidence for this diagnosis. The incidence of complex coronary lesions in this group is very low.