P6397Ejection fraction by cardiac magnetic resonance 6 months after STEMI: impact on risk stratification in chronic phase

Abstract

Abstract Background Left ventricular ejection fraction (LVEF) has traditionally been used as the cornerstone for risk stratification after STEMI and it can be accurately quantified by cine cardiovascular magnetic resonance (CMR). In recent years, the additional prognostic value of contrast CMR-derived infarct size (IS) and microvascular obstruction (MVO) soon after infarction has been demonstrated. The usefulness of CMR-derived LVEF in chronic phase for risk stratification late after STEMI is unclear. Purpose We hypothesized that 6-month CMR-derived LVEF can contribute in the prediction of clinical events late after STEMI beyond pre-discharge LVEF, IS and MVO. Methods Data were obtained from a prospective registry of reperfused STEMI patients (n=456) who were stable 6 months after infarction and in whom 1-week and 6-month CMR-derived LVEF, IS and MVO were sequentially quantified. Major adverse cardiac events (MACE) were defined as a combined clinical end-point that included death or re-admission for acute decompensated heart failure (r-ADHF), whichever occurred first, occurring after the 6-month CMR. Results During a mean and median follow-up of 6 years, 56 late MACE (12%, 32 deaths and 24 r-ADHF) were registered. From 1-week to 6-month, CMR parameters exhibited significant dynamic changes (p<0.001): LVEF improved (52±12 vs. 56±13%), IS decreased (21±14 vs. 18±12% of LV mass) and MVO vanished (2±4 vs. 0±1% of LV mass). At 6-month CMR, 60 patients (13%) displayed reduced LVEF (<40%), 69 (15%) mid-range LVEF (40–50%) and 327 (72%) preserved LVEF (≥50%). Late MACE rates were 28% in patients with reduced LVEF, 14% in those with mid-range LVEF and 9% in those with preserved LVEF at 6-month CMR (p<0.001 for the trend). After adjustment for baseline characteristics and for 1-week and 6-month CMR parameters, more preserved LVEF at 6 months independently associated with a lower risk of MACE late after STEMI (hazard ratio 0.96 [0.94–0.98] per 1% increase). Conclusions Dramatic dynamic changes occur in CMR parameters within the first months after STEMI. Reassessment of CMR-derived LVEF in chronic phase in those patients who remain stable provides relevant prognostic information for long-term risk stratification. Acknowledgement/Funding Funded by “Instituto de Salud Carlos III”/FEDER (PIE15/00013, PI17/01836, and CIBERCV16/11/00486 grants) and Generalitat Valenciana (GV/2018/116).