Development and validation of a model for predicting 18-month mortality in type 2 myocardial infarction.

BACKGROUND: Despite the poor prognosis in patients with type 2 myocardial infarction (MI), no prospective data on risk stratification exists. The aim of this study was to develop and validate a model for prediction of 18-month mortality of among patients with type 2 MI (T2MI) and compare its performance with GRACE and TARRACO scores. METHODS: The prospective observational study included 712 consecutive patients diagnosed with MI undergoing coronary angiography <24 h between January 2017 and December 2018. Diagnosis of T2MI was adjusted according to Third universal definition. A prognostic model was developed by using Bayesian approach and logistic regression analysis with identifying predictors for mortality. The model was validated by bootstrap validation. Comparison performance between scores using Delong test. RESULTS: T2MI was identified in 174 (24.4%) patients. The median age of patients was 69 years, 52% were female. The mortality rate was 20.1% at 18 months. Prior MI, presence of ST elevation, hemoglobin level at admission, Charlson comorbidity index and were independently associated with 18-month mortality. The model to predict 18-month mortality showed excellent discrimination (optimism corrected c-statistic = 0.822) and calibration (corrected slope = 0.893). GRACE and TARRACO scores had moderate discrimination [c-statistic = 0.748 (95% CI 0.652-0.843) and 0.741, 95% CI 0.669-0.805), respectively] and inferior compared with model (p = 0.043 and 0.037, respectively). CONCLUSIONS: The risk of mortality among T2MI patients could be accurately predicted by using common clinical characteristics and laboratory tests. Further studies are required with external validation of nomogram prior to clinical implementation.

Concordance and Prognostic Relevance of Angiographic and Clinical Definitions of Myocardial Infarction Type.

BACKGROUND: Atherothrombosis is the principal mechanism of type 1 (T1) myocardial infarction (MI), while type 2 (T2) MI is typically diagnosed in the presence of triggers (anemia, arrhythmia, etc.). We aimed to evaluate the proportions of T1 vs. T2 MI based on angiographic and clinical definitions, their concordance and prognosis. METHODS: Consecutive MI patients [n = 712, 61% male; age 64.6 ± 12.3 years] undergoing coronary angiography were classified according to the presence of atherothrombosis and identifiable triggers. Association of angiographic and clinical MI type criteria with adverse outcomes (Time follow-up was 1.5 years) was evaluated. Predictive ability of GRACE risk score for all-cause mortality was then assessed. RESULTS: Atherothrombosis and clinical triggers were identified in 397 (55.6%) and 324 (45.5%) subjects, respectively. Only 247 (34.7%) patients had "true" T1MI (atherothrombosis+ / triggers-); 174 (24.4%) were diagnosed with "true" T2MI (atherothrombosis- / triggers+), while 291 (40.9%) had discordant clinical and angiographic characteristics. All-cause mortality in T2MI (20.1%) patients was higher than in T1MI (9.3%), P = 0.002. Presence of triggers [odds ratio (OR) 2.4, 95% CI 1.5-3.6, P < 0.0001] but not atherothrombosis [OR 0.8, 95% confidence interval (CI) 0.5-1.3, P = 0.26] was associated with worse prognosis. GRACE score is a better predictor of death in T1MI vs. T2MI: area under curve 0.893 (95% CI 0.830-0.956) vs 0.748 (95% CI 0.652-0.843), P = 0.013. CONCLUSION: Angiographic and clinical definitions of MI type are discordant in a substantial proportion of patients. Clinical triggers are associated with all-cause mortality. Predictive performance of GRACE score is worse in T2MI patients.