Evolving towards a more realistic approach to the importance of left ventricular ejection fraction and sex in heart failure and its therapy

Clinical Characteristics and Outcomes in Patients With Heart Failure: Are There Thresholds and Inflection Points in Left Ventricular Ejection Fraction and Thresholds Justifying a Clinical Classification?

BACKGROUND

Recent guidelines proposed a classification for heart failure (HF) on the basis of left ventricular ejection fraction (LVEF), although it remains unclear whether the divisions chosen were biologically rational. Using patients spanning the full range of LVEF, we examined whether there was evidence of LVEF thresholds in patient characteristics or inflection points in clinical outcomes.

METHODS

Using patient-level information, we created a merged dataset of 33 699 participants who had been enrolled in 6 randomized controlled HF trials including patients with reduced and preserved ejection fraction. The relationship between the incidence of all-cause death (and specific causes of death) and HF hospitalization, and LVEF, was evaluated using Poisson regression models.

RESULTS

As LVEF increased, age, the proportion of women, body mass index, systolic blood pressure, and prevalence of atrial fibrillation and diabetes increased, whereas ischemic pathogenesis, estimated glomerular filtration rate, and NT-proBNP (N-terminal pro-B-type natriuretic peptide) decreased. As LVEF increased >50%, age and the proportion of women continued to increase, and ischemic pathogenesis and NT-proBNP decreased, but other characteristics did not change meaningfully. The incidence of most clinical outcomes (except noncardiovascular death) decreased as LVEF increased, with a LVEF inflection point of around 50% for all-cause death and cardiovascular death, around 40% for pump failure death, and around 35% for HF hospitalization. Higher than those thresholds, there was little further decline in the incidence rate. There was no evidence of a J-shaped relationship between LVEF and death; no evidence of worse outcomes in patients with high-normal ("supranormal") LVEF. Similarly, in a subset of patients with echocardiographic data, there were no structural differences in patients with a high-normal LVEF suggestive of amyloidosis, and NT-proBNP levels were consistent with this conclusion.

CONCLUSIONS

In patients with HF, there was a LVEF threshold of around 40% to 50% where the pattern of patient characteristics changed, and event rates began to increase compared with higher LVEF values. Our findings provide evidence to support current upper LVEF thresholds defining HF with mildly reduced ejection fraction on the basis of prognosis.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifiers: NCT00634309, NCT00634400, NCT00634712, NCT00095238, NCT01035255, NCT00094302, NCT00853658, and NCT01920711.

Heart Failure With Midrange Ejection Fraction-What Is It, If Anything?

The patient cohort with left ventricular ejection fractions (LVEFs) of 41%-49%, which has been defined as heart failure with midrange ejection fraction (HFmrEF), represent a significant proportion of the heart failure (HF) population. Despite the clear cutoffs established by different society guidelines, confusion remains regarding the exact significance of midrange LVEF within the HF syndrome. Patients with LVEF 41%-49% represent a heterogeneous group of patients sharing pathophysiologic mechanisms, biomarker profiles, comorbidities, and clinical characteristics with patients with preserved and reduced LVEF. In this clinical review, we discuss the underlying pathophysiologic mechanisms that culminate in the clinical syndrome of HF and contribute to the disparities observed between HFpEF, HFrEF, and HFmrEF. We highlight differences and similarities in clinical characteristics and imaging features between HFpEF and HFrEF in an effort to disentangle the heterogeneous group of patients with midrange LVEF, but ultimately we conclude that LVEF should be seen as simply one important element of a continuum throughout the HF syndrome, and that although is useful, it is an oversimplification, because HF syndrome is more of a continuum. The underlying pathophysiology, etiology, and comorbidities of patients presenting with HF is becoming ever more important as the limitations of a classification solely based on LVEF are being better recognised, and as patient-specific personalisation of care is becoming ever more important.