What is the clinical evidence from this study?

Study design: Cohort. Population: Congestive heart failure with iron deficiency (n=40). Intervention: Iron dextran complex vs. Baseline. Primary outcome: 6 minute walk distance (p=< 0.01).

What question did this study set out to answer?

The aim is to evaluate how correcting iron deficiency affects heart function and exercise abilities in CHF patients.

November 2, 2011

Tissue Doppler and Strain Rate Imaging Detect Improvement of Myocardial Function in Iron Deficient Patients with Congestive Heart Failure after Iron Replacement Therapy

Q: What are the key findings of this study?

Iron replacement therapy significantly improved 6-minute walk distance (322 vs 377, P<0.01) and myocardial function in nonanemic iron-deficient patients with systolic heart failure.

Q: What question did this study set out to answer?

The aim is to evaluate how correcting iron deficiency affects heart function and exercise abilities in CHF patients.

Key Result

Iron replacement therapy significantly improved 6-minute walk distance (322 vs 377, P<0.01) and myocardial function in nonanemic iron-deficient patients with systolic heart failure.

Key Points

The aim is to evaluate how correcting iron deficiency affects heart function and exercise abilities in CHF patients.
Studied 40 patients with CHF and iron deficiency, administering 200 mg of iron dextran weekly until ferritin reached 200-300 ug/L.
Assessments included trans-thoracic echocardiogram, tissue Doppler imaging, and a 6-minute walk test at baseline and 12-week follow-up.
Measured variables included E', A', S' myocardial tissue velocities and the E/E' ratio.
NYHA functional class improved significantly from 3.0 ± 0.4 to 2.1 ± 0.3 (P < 0.05).
6-minute walk distance increased from 322 ± 104 to 377 ± 76 meters (P < 0.01).
S'-wave improved from 3.0 ± 0.8 cm/sec to 6.0 ± 1.2 cm/sec (P < 0.05) and the E/E' ratio from 22 ± 3 to 13 ± 3 (P < 0.05).

Study Design

Type

Cohort (n=40)

PICO

Population

Congestive heart failure with iron deficiency (n=40)

Intervention / Comparator

Iron dextran complex vs Baseline (200 mg weekly)

Primary Outcome

6 minute walk distance, p=< 0.01

Main Result

Absolute Event Rate: 377% vs 322%

p-value: p=< 0.01

Abstract

BACKGROUND: Iron deficiency may contribute to diminished exercise tolerance in patients with congestive heart failure (CHF) even in absence of anemia. The aim of this study was to evaluate the effect of correction of iron deficiency on functional capacity and myocardial function in patients with CHF. METHODS: We studied 40 patients with ejection fraction 12 g/dL, serum ferritin <100 ug/L, and transferrin saturation <20%. Patients received 200 mg weekly doses of iron dextran complex until serum ferritin level was between 200 and 300 ug/L or transferrin saturation level was between 30% and 40%. Transthoracic echocardiogram, tissue Doppler imaging, peak systolic strain rate, and 6 minute walk test were performed before iron therapy and at 12-week follow up. Peak early diastolic myocardial tissue velocity (E'), peak late diastolic myocardial tissue velocity (A'), and peak systolic myocardial tissue velocity (S') were measured. RESULTS: There was a significant improvement of New York Heart Association functional class (3.0 ± 0.4 vs. 2.1 ± 0.3, P < 0.05) and 6minutes walk distance (322 ± 104 vs. 377 ± 76, P < 0.01) from rest to follow up, respectively. Ejection fraction did not change significantly (32 ± 8% vs. 34 ± 9%, respectively). There was a significant improvement of S'-wave (3.0 ± 0.8 cm/sec vs. 6.0 ± 1.2 cm/sec, P < 0.05), E/E' ratio (22 ± 3 vs. 13 ± 3, P < 0.05), and peak systolic strain rate (-0.72 ± 0.11/s vs. -1.09 ± 0.37/s, P < 0.05) from baseline to follow-up, respectively. CONCLUSION: Correction of iron deficiency improves functional class and walking distance in nonanemic iron deficient patients with systolic heart failure. Tissue Doppler and strain rate demonstrated a significant improvement of diastolic and systolic function after therapy despite lack of improvement of ejection fraction. (Echocardiography 2012;29:13-18).

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