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Usefulness of Heart Failure Categories Based on Left Ventricular Ejection Fraction
Malin Christersson1, Stefan Gustafsson2, Erik Lampa1
1Department of Medical Sciences Uppsala University Uppsala Sweden.
Insights
New heart failure guidelines created a mildly reduced ejection fraction category, but LVEF is highly variable. This category is unstable, with patients frequently changing LVEF status within a year.
Area of Science:
- Cardiology
- Clinical Medicine
- Medical Guidelines
Background:
- Recent heart failure guidelines introduced a new category: heart failure with mildly reduced ejection fraction (LVEF 41%-49%).
- This category sits between heart failure with reduced ejection fraction (LVEF ≤40%) and heart failure with preserved ejection fraction (LVEF ≥50%).
- Categorizing continuous measurements with high variability can be problematic.
Purpose of the Study:
- To assess the variability and stability of left ventricular ejection fraction (LVEF) categories in heart failure patients.
- To evaluate the clinical implications of the newly introduced heart failure with mildly reduced ejection fraction category.
Main Methods:
- A cohort of 9716 new chronic heart failure cases with available LVEF in Stockholm (2015-2020) was analyzed.
- Mixed models quantified within-person LVEF variance; multistate Markov models assessed LVEF category stability.
- Patient LVEF values were tracked over time, with follow-up until death or study end.
Main Results:
- Left ventricular ejection fraction (LVEF) followed a normal distribution with a significant within-person standard deviation of 7.4%.
- The mean time spent in any LVEF category was less than one year for heart failure with mildly reduced ejection fraction.
- There was a substantial probability of transitioning between LVEF categories within the first year; <25% of patients with mildly reduced LVEF remained in that category after one year.
Conclusions:
- Left ventricular ejection fraction (LVEF) exhibits considerable variability over time, challenging the stability of narrow diagnostic categories.
- The heart failure with mildly reduced ejection fraction category is particularly inconstant, with frequent LVEF fluctuations.
- Clinical decisions and treatment strategies should account for the inherent variability and normal distribution of LVEF in heart failure patients.
Background:
Heart failure guidelines have recently introduced a narrow category with mildly reduced left ventricular ejection fraction (LVEF) (heart failure with mildly reduced ejection fraction; LVEF 41%-49%) between the previous categories of reduced (heart failure with reduced ejection fraction; LVEF ≤40%) and preserved (heart failure with preserved ejection fraction; LVEF ≥50%) ejection fraction. Grouping of continuous measurements into narrow categories can be questioned if their variability is high.
Methods And Results:
We constructed a cohort of all 9716 new cases of chronic heart failure with an available LVEF in Stockholm, Sweden, from January 1, 2015, until December 31, 2020. All values of LVEF were collected over time, and patients were followed up until death, moving out of Stockholm, or end of study. Mixed models were used to quantify within-person variance in LVEF, and multistate Markov models, with death as an absorbing state, to quantify the stability of LVEF categories. LVEF values followed a normal distribution. The SD of the within-person variance in LVEF over time was 7.4%. The mean time spent in any LVEF category before transition to another category was on average <1 year for heart failure with mildly reduced ejection fraction. Probabilities of transitioning between categories during the first year were substantial; patients with heart failure with mildly reduced ejection fraction had a probability of <25% of remaining in that category 1 year later.
Conclusions:
LVEF follows a normal distribution and has considerable variability over time, which may impose a risk for underuse of efficient treatment. The heart failure with mildly reduced ejection fraction category is especially inconstant. Assumptions of a patient's current LVEF should take this variability and the normal distribution of LVEF into account.
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