The FIBR-CMR score: a novel risk model integrating fibrinogen and cardiac magnetic resonance for major adverse events after STEMI.

BACKGROUND

Survivors of ST-segment elevation myocardial infarction (STEMI) face a substantial residual risk of major adverse cardiovascular and cerebrovascular events (MACCEs). Cardiac magnetic resonance (CMR) excellently delineates structural injury but does not assess the concomitant systemic prothrombotic state. We investigated whether fibrinogen, a key mediator of thrombosis, provides incremental prognostic value beyond CMR for risk stratification.

METHODS

In a prospective multicenter cohort of 532 STEMI patients undergoing primary percutaneous coronary intervention (PCI), plasma fibrinogen was measured post-procedure. CMR was performed within 7 days to assess left ventricular thrombus (LVT) and aneurysm (LVA). The primary endpoint was MACCEs over a median follow-up of 55.5 months. A novel risk score (the Fibrinogen and Cardiac Magnetic Resonance Score, or FIBR-CMR score) was derived from a multivariable Cox model, and its performance was assessed through internal validation using bootstrap resampling (optimism-corrected C-index = 0.73).

RESULTS

Elevated fibrinogen independently predicted LVT (adjusted OR 1.46, 95% CI 1.09-1.96) and LVA (adjusted OR 1.47, 95% CI 1.20-1.79) after adjusting for clinical and CMR confounders. Fibrinogen (≥ 3.36 g/L) independently predicted MACCEs (HR 1.30, 95% CI 1.10-1.53), an effect partially mediated by LVT (48.5%) and LVA (38.0%). The FIBR-CMR score (1 point for elevated fibrinogen, 2 for LVT, 2 for LVA) stratified patients into low (0 points), intermediate (1-2 points), and high (≥ 3 points) risk groups. The high-risk group had a strikingly elevated 5-year MACCE incidence of 48.3%, compared to 15.2% and 6.0% in the intermediate- and low-risk groups, respectively (optimism-corrected C-index = 0.73).

CONCLUSION

The integration of fibrinogen with CMR-defined structural injury provides powerful synergism for risk assessment. The FIBR-CMR score, derived from a prospective multicenter cohort, effectively identifies a high-risk phenotype of STEMI patients. This score now requires external validation but represents a promising step toward personalized risk assessment.

CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov; NCT03768453.