Prognostic Value of Systemic Inflammation Response Index and N-Terminal Pro-B-Type Natriuretic Peptide in Patients with Myocardial Infarction with Nonobstructive Coronary Arteries- A Retrospective Study.

Background: The Systemic Inflammation Response Index (SIRI) and N-terminal Pro-B-type natriuretic peptide (NT-proBNP) have been proposed as reliable predictors of poor prognosis in cardiovascular disease and all-cause mortality, However, their validity has not been extensively evaluated in patients with myocardial infarction with nonobstructive coronary arteries (MINOCA).

Patients and methods: 259 patients diagnosed with MINOCA were enrolled in this study from January 2015 to December 2022, and serum levels of SIRI and NT-proBNP were detected. The primary endpoints were major adverse cardiovascular events (MACE). According to the occurrence of MACE during the follow-up period, patients were grouped into MACE and Non-MACE groups, and divided by the median values for SIRI and NT-proBNP into groups: low SIRI, high SIRI, low NT-proBNP, and high NT-proBNP.

Results: A statistically significant difference in the levels of SIRI and NT-proBNP was observed between the MACE group and the non-MACE group. Kaplan-Meier survival curve analysis revealed that patients with high SIRI and high NT-proBNP had a significantly higher risk of MACE (log-rank P < 0.001). Furthermore, even after adjusting for covariates, the high SIRI and high NT-proBNP were associated with an increased risk of MACE (P<0.001, HR: 3.188, 95% CI 1.940-5.241; P<0.001, HR: 2.245, 95% CI 1.432-3.519). Additionally, the combined prognosis prediction of SIRI and NT-proBNP was superior to a single prediction, and adding SIRI and NT-proBNP to the traditional risk factor model improved the model's predictive value.

Conclusion: High levels of SIRI and NT-proBNP exhibit a significant correlation with an increased risk of MACE, thereby suggesting that SIRI can be used as a reliable inflammatory indicator for predicting the risk in MINOCA patients, with significantly improved prognostic value when combined with NT-proBNP.