Inflammatory Burden Index is Associated with Increased Long-Term Risk of Major Advers Cardiovascular Events in Myocardial Infarction with Non-Obstructive Coronary Arteries

Background: Myocardial infarction with non-obstructive coronary arteries (MINOCA) refers to patients who meet the universal definition of acute myocardial infarction but show no significant stenosis on coronary angiography, and it is associated with a non-benign prognosis. The prognostic relevance of inflammatory burden index (IBI), a useful inflammatory biomarker, in patients with MINOCA remains to be elucidated. We evaluated the association between the IBI and long-term major adverse cardiovascular events (MACE) in MINOCA. Methods: In this single-center retrospective cohort, we included 267 consecutive patients with clinically diagnosed MINOCA. Cox proportional hazards models assessed associations between baseline IBI and MACE. Discrimination was evaluated using receiver operating characteristic (ROC) analysis with area under the curve (AUC) comparisons by the DeLong test. Results: Over a median follow-up of 42 (15, 56) months, 53 MACE occurred (19.9%). In multivariable models adjusting for clinical covariates and key biomarkers, IBI remained independently associated with MACE (HR 1.342, 95% CI 1.168-1.542; P < 0.001), as did NT-proBNP (HR 1.711, 95% CI 1.446-2.023; P < 0.001) and the ST-segment elevation (HR 1.780, 95% CI 1.031-3.075; P = 0.039). For predicting MACE, IBI achieved an AUC of 0.737 (95% CI 0.673-0.801), outperforming hs-CRP (AUC 0.698, 95% CI 0.630-0.766) and NLR (AUC 0.650, 95% CI 0.564-0.736). Patients with high IBI had a significantly higher cumulative incidence of MACE on Kaplan-Meier analysis (log-rank P < 0.001). Conclusion: Elevated IBI is an independent risk factor of long-term MACE in MINOCA. As an inexpensive, routinely available composite biomarker, IBI may aid risk stratification and follow-up planning in MINOCA. Despite these findings, the external generalizability of this study is limited by its design.