Objectives The Braunwald classification and TIMI score are the most useful and frequently used tools of clinical assessment for stratifying cardiovascular risk in patients with unstable angina (UA). However, these scores have a limited capacity when they are used alone. This study sought to evaluate the value of multiple blood biomarkers and computed tomographic angiography (CTA) characteristics in patients with UA. Furthermore, to compare the Braunwald classification and TIMI score with the two new created risk scores based on biomarkers and CTA for predicting short-term outcomes in patients with UA.
Methods The study group consisted of 186 patients confirmed UA between November 2011 and May 2012. Diagnosis was made by assessing chest pain, typical electrocardiographic changes and/or elevation of cardiac enzymes. Follow-up time was 6 months with major adverse cardiac events (MACEs) as cardiovascular death, revascularization, recurrent acute coronary syndrome (ACS) and re-admission in hospital. Multiple Blood biomarkers including high-sensitivity cardiac troponinT (hs-cTnT), N-terminal pro–B-type natriuretic peptide (NT-proBNP), high-sensitivity C-reactive protein (hs-CRP), myeloperoxidase (MPO) and ischemia-modified albumin (IMA) were measured. CTA characteristics such as stenosis, plaque, epicardial fat volume (EFV) and calcification were evaluated. MACEs and biomarkers were analysed. Also, the relationships between MACEs and CTA characteristics were analysed. The two novel risk scores including SPEC (Stenosis, Plaque, EFV and Calcification by CTA) and BETTER (BiomarkErs and compuTed Tomography scorE on Risk stratification) scores were assessed in 186 patients. ROC (receiver-operating characteristics) curves were used to evaluate the ability of variables and the risk scores including Braunwald, TIMI, SPEC and BETTER to predict MACEs.
Results In 6 months follow-up, 107 (57.53%) MACEs occurred, consisting of 2 cardiac deaths (1.07%), 15 non-fatal myocardial infarctions (8.06%), revascularization including 59 PCI (31.72%) and 5 CABG (2.69%), 26 recurrent ACS and re-admission in hospital (13.98%). Serum levels of MPO, NT-proBNP, hs-cTnT, hs-CRP and CTA characteristics of stenosis, plaque, EFV and calcification in the group with MACEs (n = 107) were significantly higher than the group without MACEs (n = 79). However, IMA were no statistics differences between two groups. Area under curves (AUC) of ROC for MPO, NT-proBNP, hs-cTnT, hs-CRP and IMA were 0.614, 0.622, 0.542, 0.626 and 0.579 respectively. Area under curves (AUC) of ROC for stenosis, plaque, EFV and calcification were 0.834, 0.766, 0.666 and 0.633 respectively. The AUC for SPEC was greater than Braunwald classification and TIMI risk scores (0.902 vs 0.591 and 0.643, p < 0.05, p < 0.001) respectively. The AUC for BETTER was observed as (0.908 vs 0.591 and 0.643, p < 0.001, p < 0.001). SPEC risk score and BETTER risk score have no statistical difference (p > 0.05).
Conclusions The SPEC risk score which based on CTA and BETTER risk scores integrating CTA and biomarkers are both new tools specifically developed for patients with UA. These scores displayed prediction accuracy in terms of discrimination and calibration than other currently available scores for risk stratification.