Borderline coronary lesions may lead to serious coronary events--long-term outcome in 65 conservatively treated patients.

BACKGROUND: The choice of optimal therapy in a patient with borderline coronary lesion is difficult. The long-term outcome of conservatively treated patients has not yet been well defined. AIM: To analyse long-term outcome in patients with a borderline lesion in a single coronary artery who were selected for conservative treatment. METHODS: The study group consisted of 65 patients (mean age 59.4+/-7.4 years, 48 males) with (1) stable angina (CCS class I/II), (2) isolated single borderline coronary lesion (40-70% stenosis demonstrated by quantitative coronary angiography) and (3) no demonstrable ischaemia during non-invasive tests. Patients with heart failure, left ventricular ejection fraction <50% or acute coronary syndrome within 6 months preceding the study were not included. All patients were prescribed statins, angiotensin converting enzyme inhibitors and aspirin. Follow-up end-points included cardiac death, new myocardial infarction (MI) with or without ST segment elevation and revascularisation of the target coronary artery. RESULTS: The follow-up duration was 18.4+/-8.5 months (range 12-33, median 18 months). Forty nine (75%) patients remained free from angina during daily activity. Coronary events occurred in 16 (25%) patients, including three (5%) serious complications -- sudden death, new MI with ST elevation and new MI without ST elevation. The remaining 13 (20%) patients underwent percutaneous revascularisation of the target coronary artery. Coronary angiography was repeated in 16 (25%) patients. When the patients were divided into two groups according to the follow-up results (with or without coronary event), no differences in the clinical characteristics, lesion localisation and length or degree of stenosis were noted. CONCLUSIONS: (1) Conservatively treated patients with stable angina and borderline coronary stenosis have a high rate of coronary events, especially revascularisation, during a long-term follow-up. (2) Clinical parameters and quantitative coronary angiography do not identify those patients with borderline coronary lesions who are at increased risk of future coronary events.