Is unstable angina a benign disease? A prospective multicenter contemporary study

Abstract

Introduction

The use of high sensitivity cardiac troponin (hs-cTn) for the diagnostic strategy of acute coronary syndromes (ACS) resulted in decrease of unstable angina (UA) to the benefit of NSTEMI. However, prognostic of UA remains controversial with no precise guidelines.

Objective

To evaluate clinical characteristics and prognostic of a contemporary patients with UA.

Method

The study included all patients admitted in 2 French university centres with the diagnostic of UA defined with clinical ischemic symptoms and T hs-cTn concentrations < 99 percentile (undetectable: < 5 ng/l or non-elevated: < 14 ng/l) or ≥ 99 percentile but mildly elevated (14–50 ng/l) without significant rise (< 20%) between 2 dosages. Only patients with significant coronary stenosis were included. The primary end-point included major events at 1-year follow-up (total mortality, new ACS, hospitalization for cardiac causes).

Results

Among 1682 patients admitted for ACS during the study period (December 2021–February 2023), 210 were diagnosed to have UA (12.5%). Mean age of patients with UA was 66 ± 12 years, with predominantly males (68.1%). The patients with UA had undetectable (n = 4), non-elevated (n = 80) or moderately elevated T hs-cTn with no kinetics (n = 126). At least 2 cardiovascular risk factors were observed in 60.9% patients and a history of coronary artery disease (CAD) was found in 46.6% patients. Coronary angiography showed multitroncular disease in 56,7% patients and a mean SYNTAX 1 score of 8.27 ± 5.06. Percutaneous coronary angioplasty was performed in 88.6% patients while 7.14% required bypass surgery. Only one adverse event occurred during the hospital phase related to documented stroke. Regarding the primary outcome, 55 patients had an adverse event (26.2% [20.2–32.1]) mainly related to new ACS (Table 1). The level of troponin was not associated with the primary outcome in univariate analysis nor was the SYNTAX I score. In multivariate logistic regression analysis, ≥ 3 cardiovascular risk factors (OR 1.93 [1.01–3.69], p = 0.0194), history of CAD (OR 3.09 [1.63–5.87], p = 0.0005), previous antiplatelet therapy (OR 2.54 [1.11–5.84], p = 0.0279) and tritroncular disease (OR 2.66 [1.24–5.69], p = 0.0118) were significantly associated with major events at follow-up.

Conclusion

Incidence of UA is low (12.5% of all ACS) but with a 1-year incidence of major cardiac events high (26.2%), mainly related to new acute coronary event. UA is therefore not a benign disease and secondary prevention has probably to be improved.