Derivation and validation of a scoring system to predict after discharge risk of cardiac events in patients with acute myocardial infarction undergoing percutaneous coronary revascularization

Abstract

Abstract Background In the acute coronary syndromes (ACS) setting, despite the extensive use of coronary revascularization and P2Y12 inhibitors such as prasugrel and ticagrelor, with a more pronounced inhibitory effect on platelets than clopidogrel, the rate of death and recurrent myocardial infarction (MI) at 1 year is still high. In this clinical setting the development of a risk score which takes into account patient's and procedural characteristics could represent a useful tool to identify patients at high risk for ischaemic events at 1 year who could take advantage from more aggressive secondary prevention strategies. Purpose The aim of our study was to develop a risk score to predict 1-year probability of after discharge cardiac events (recurrent MI and cardiac death) in patients with acute MI treated with percutaneous coronary intervention (PCI). Methods We prospectively enrolled all consecutive patients hospitalized for acute MI between 2003 and 2017 treated with PCI with/without stent placement at our center. We excluded patients who died in-hospital or who experienced in-hospital recurrent MI and patients undergoing surgical revascularization by coronary artery bypass graft (CABG). The patients of the final study cohort were therefore randomly assigned to either a derivation sample (60%) or a validation sample (40%). Based on the multivariate analysis we developed a point system according to the “Framingham Risk Score” method. Results The final study cohort, represented by 4922 patients, was split in a derivation sample of 2972 patients and in a validation sample of 1950 patients: in both groups the median age was around 70 years; the male prevalence was 73%; 65% of patients were dagnosed with ST-segment elevation MI. The clinical prediction score underlined as risk factors for recurrent cardiac events older age, diabetes mellitus, peripheral arterial disease, prior MI, Killip class >2 at presentation, higher platelet count and creatinine values, lower left ventricular ejection fraction; radial access and the use of second generation drug eluting stents resulted to be protective. This model showed a good discrimination power in both the derivation and the validation samples with an area under the curve (AUC) of 0.75 and 0.71, respectively. The calibration showed a good concordance between predicted and observed events in both the derivation and the validation samples. Same results were observed in patients with/without ST-segment elevation MI and in gender subgroups. Conclusions The present study, conducted retrospectively on a large population of patients with acute MI treated with PCI enrolled prospectively, enabled us to derivate and validate a risk score of cardiac death and recurrent MI at 1 year which took into account both clinical and procedural characteristics and which demonstrated a good predictive performance. After-discharge events by risk subgroups Funding Acknowledgement Type of funding source: None