Prognostic value of systolic left ventricular ejection fraction using prospective ECG-triggered cardiac CT.

Background: Prospective ECG-triggered cardiac computed tomography (CT) imaging limits the ability to assess left ventricular (LV) ejection fraction (EF). We previously developed a new index derived from LV volume changes over 100 ​ms during systole (LVEF) as a surrogate of LV function in patients undergoing prospective ECG-triggered cardiac CT. We sought to evaluate the prognostic value of LVEF.

Methods: Patients undergoing prospective systolic ECG-triggered cardiac CT were enrolled between January 2015 and September 2022. Each CT was analyzed for LVEF. Area under the curve analysis and Cox proportional hazards models were used to define the best LVEF cut-off and to predict major adverse cardiovascular events (MACE), defined as a composite of all-cause death, cardiac death/arrest, non-fatal myocardial infarction, and stroke.

Results: The study enrolled 313 patients (median age ​= ​58 years, male ​= ​52.4 ​%). During a median follow-up of 924 (660-1365) days, 24 (7.7 ​%) patients had MACE. LVEF was significantly lower in the MACE group compared to the non-MACE group (4.8 ​% vs. 8.3 ​%, p ​= ​0.002). Optimal LVEF cut-off for predicting MACE was 6.3 ​%. MACE-free survival rate was significantly lower in patients with LVEF ≤6.3 ​% than those with >6.3 ​% (p ​< ​0.001). LVEF ≤6.3 ​% was an independent predictor of MACE, with an adjusted hazard ratio of 3.758 (95 ​% CI, 1.543-9.148; p ​= ​0.004). The prognostic value of LVEF was consistent across the various severities of coronary artery disease.

Conclusion: LVEF was an independent predictor of adverse events. The implementation of LVEF may improve the prognostic value of prospective ECG-triggered cardiac CT.