Significance of Ischemic Heart Disease in Patients With Heart Failure and Preserved, Midrange, and Reduced Ejection Fraction: A Nationwide Cohort Study.

BACKGROUND The pathogenic role of ischemic heart disease (IHD) in heart failure (HF) with reduced ejection fraction (HFrEF; EF <40%) is well established, but its pathogenic and prognostic significance in HF with midrange (HFmrEF; EF 40%-50%) and preserved EF (HFpEF; EF ≥50%) has been much less explored. METHODS AND RESULTS We evaluated 42 987 patients from the Swedish Heart Failure Registry with respect to baseline IHD, outcomes (IHD, HF, cardiovascular events, and all-cause death), and EF change during a median follow-up of 2.2 years. Overall, 23% had HFpEF (52% IHD), 21% had HFmrEF (61% IHD), and 55% had HFrEF (60% IHD). After multivariable adjustment, associations with baseline IHD were similar for HFmrEF and HFrEF and lower in HFpEF (risk ratio, 0.91 [0.89-0.93] versus HFmrEF and risk ratio, 0.90 [0.88-0.92] versus HFrEF). The adjusted risk of IHD events was similar for HFmrEF versus HFrEF and lower in HFpEF (hazard ratio, 0.89 [0.84-0.95] versus HFmrEF and hazard ratio, 0.84 [0.80-0.90] versus HFrEF). After adjustment, prevalent IHD was associated with increased risk of IHD events and all other outcomes in all EF categories except all-cause mortality in HFpEF. Those with IHD, particularly new IHD events, were also more likely to change to a lower EF category and less likely to change to a higher EF category over time. CONCLUSIONS HFmrEF resembled HFrEF rather than HFpEF with regard to both a higher prevalence of IHD and a greater risk of new IHD events. Established IHD was an important prognostic factor across all HF types.