Altered thyroid hormone metabolism in advanced heart failure

Area of Science:

• Cardiology
• Endocrinology
• Metabolic Research

Background:

• Congestive heart failure (CHF) is associated with altered thyroid hormone levels.
• The clinical significance of these alterations in advanced CHF requires further elucidation.

Purpose of the Study:

• To investigate the prevalence and prognostic value of abnormal thyroid hormone metabolism in hospitalized patients with chronic advanced heart failure.
• To assess the relationship between thyroid hormone indices and clinical parameters, as well as patient outcomes.

Main Methods:

• Measured free thyroxine (T4) index, free triiodothyronine (T3) index, reverse T3, and thyrotropin in 84 advanced CHF patients.
• Analyzed correlations between thyroid hormone ratios and hemodynamic, functional, and biochemical markers.
• Evaluated the predictive power of the free T3 index/reverse T3 ratio for short-term (6-week) and long-term (1-year) outcomes.

Main Results:

• Free T4 index was normal in all patients.
• A low free T3 index/reverse T3 ratio was observed in 58% of patients, correlating with elevated cardiac pressures and reduced cardiac function.
• The free T3 index/reverse T3 ratio was the sole independent predictor of poor 6-week outcome (p < 0.001) and was strongly associated with 1-year survival (100% vs. 37%, p < 0.0001).

Conclusions:

• Abnormal thyroid hormone metabolism, specifically a low free T3 index/reverse T3 ratio, is prevalent in advanced heart failure.
• This ratio serves as a powerful independent predictor of poor short-term prognosis and reduced long-term survival in this patient population.
• The findings highlight the importance of assessing thyroid hormone metabolism in managing advanced heart failure.