Abstract 17848: Evolving Iron Deficiency Confers Most of the Adversity Associated with a Temporal Rise in Red Cell Distribution Width, is More Ominous than a Falling Hemoglobin, and Blunts Left Ventricular Long Axis Function in Chronic Heart Failure
Background: Whilst a progressive rise in the red cell distribution width (RDW) can reflect many aberrations that exacerbate chronic heart failure (CHF), the combination of a rising RDW and falling mean cell volume (MCV) signifies evolving iron deficiency (ID). Because iron is critical for multiple physiological processes and ID in animal models subtly impairs myocyte contractility, we hypothesised that evolving ID might be primarily responsible for the adverse prognosis conferred by a rising RDW, and might attenuate sensitive indices of myocardial systolic performance.
Methods: We analysed the 1 year survival implications of evolving ID in a derivation cohort of 211 CHF outpatients (age 68±12y, LVEF 29±9%, NYHA class 2±1) and validated this in another 174 from a separate institution. Repeat tissue doppler mitral annular systolic velocities (S’) were available in 34 patients (pts).
Results: In the derivation cohort, 56 (27%) pts had evolving ID and 31 (15%) died. Pts with evolving ID had greater reductions in S’ over time than those who did not (-0.5 cm/sec vs. 1.0 cm/sec, P<0.05). In Cox analyses, evolving ID predicted mortality (HR 3.43, CI 1.68 - 7.04, P<0.001) independently of all covariates and incremented χ2 values when added to baseline models. A [[Unable to Display Character: ∆]]RDW > 1.1% and a [[Unable to Display Character: ∆]]MCV ≤ -1 fL optimally forecasted death with their combination identifying those at a 6-fold escalated risk (HR 5.84, CI: 2.73 - 12.51, P<0.0001). Pts with evolving ID had a worse outcome than those with a rising RDW alone (Fig A), and those with evolving ID without falling Hb levels had a poorer prognosis than those with a falling Hb without evolving ID (Fig B). In the validation cohort, 30 (17%) pts died. Again, evolving ID was more ominous than a rising RDW or a falling Hb alone.
Conclusions: Evolution of simple erythrocyte indices towards an iron deficient picture can identify CHF patients at a 6-fold increased risk for mortality. Evolving ID is associated with worsening LV longitudinal function and should be targeted.
- © 2012 by American Heart Association, Inc.