Reduced right/left ventricular blood pool T2-ratio predicts congestive heart failure after STEMI.

BACKGROUND

T2-mapping of the blood-pool in cardiac magnetic resonance imaging (CMR) provides important information on blood-oxygenation, and differences between right and left ventricular (RV/LV) T2-relaxation times are linked to exercise capacity in heart failure. However, there are no data available on RV/LV T2-ratio after ST-segment elevation myocardial infarction (STEMI). Our aim was to investigate the prognostic value of RV/LV T2-ratio for the development of newly diagnosed congestive heart failure (CHF) post-STEMI.

METHODS

Six hundred four patients were enrolled after revascularized first-time STEMI; all patients underwent CMR within four days afterwards (interquartile range (IQR) 2-5). T2 relaxation times were measured in the RV and LV blood pool on short-axis T2-maps; T2-ratio was calculated as T2RV/T2LV. Telephonic follow-ups were performed at a median observation interval of 3.0 years. CHF was defined as cardiac decompensation symptoms requiring i.v. diuretics.

RESULTS

Median T2-ratio was 73% (IQR 65-80) and significantly lower in patients with newly diagnosed CHF (69% vs. 73%, p = 0.019). Dichotomized at 60% (10th percentile), patients with a reduced T2-ratio experienced CHF significantly more often (19% vs. 6%, p < 0.001) and sooner (55 vs. 485 days, p < 0.001) and were significantly older, had larger infarcts, higher peak troponin T, N-terminal pro-brain natriuretic peptide (NT-proBNP), lower LV-/RV-ejection fraction, and more commonly microvascular injuries (all p < 0.05). In logistic regression, T2-ratio < 60% emerged as an independent prognostic marker in multiparametric models including classic CHF risk factors. Addition of RV/LV T2-ratio to NT-proBNP resulted in a net reclassification improvement of 0.32 (95% CI 0.06-0.57, p = 0.016).

CONCLUSION

CMR-derived RV/LV T2-ratio is an easily applicable tool bearing prognostic potential for CHF after STEMI.