Prognostic Value of NPAR/UAR in MINOCA Patients with Coronary Slow Flow Phenomenon

Patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) combined with the coronary slow flow phenomenon (CSFP) often exhibit microvascular dysfunction. However, the underlying inflammation-metabolism interplay and effective prognostic tools remain unclear. This study aimed to investigate the predictive value of two novel inflammation-metabolism composite biomarkers, the neutrophil-to-albumin ratio (NPAR) and the uric acid-to-albumin ratio (UAR), in MINOCA patients with CSFP and to assess the synergistic effect of these markers on short-term outcomes.

A total of 176 MINOCA patients were prospectively enrolled, including 61 with CSFP diagnosed via corrected TIMI frame count (CTFC) and 115 with normal coronary flow as controls. Baseline clinical data, inflammation-metabolism biomarkers (NPAR, UAR), and imaging parameters were collected. Patients were followed for one year to track a composite endpoint, including cardiovascular death, recurrent myocardial infarction, and heart failure hospitalization. Multivariable logistic regression and Cox proportional hazards models were used to analyze the independent and interactive effects of NPAR and UAR. Model performance improvement was evaluated using the net reclassification improvement (NRI) and integrated discrimination improvement (IDI) indices.

MINOCA patients with CSFP showed significantly elevated levels of both NPAR and UAR. Multivariate analysis revealed that NPAR (OR = 1.45, p = 0.008), UAR (OR = 1.35, p = 0.04), and their interaction term (OR = 1.30, p = 0.02) were independent predictors of the composite endpoint. Combined assessment of these biomarkers significantly improved risk stratification (AUC increased from 0.73 to 0.75; NRI = 0.12, IDI = 0.015). The Cox model further confirmed an increased risk of 30% of adverse events with NPAR/UAR interaction (HR = 1.30, p = 0.027), with no significant effect modification by CSFP status (p > 0.05).

Elevated NPAR and UAR levels jointly predict poor short-term outcomes in MINOCA patients, and their synergistic effect is independent of CSFP status. These findings suggest a novel biomarker-based strategy for risk stratification and targeted intervention in microvascular myocardial infarction.