Higher Peripheral Thyroid Sensitivity Is Linked to a Lower Risk of Heart Failure After Acute Myocardial Infarction

Area of Science:

• Cardiology
• Endocrinology
• Internal Medicine

Background:

• The prognostic impact of the free triiodothyronine (FT3) to free thyroxine (FT4) ratio on outcomes after acute myocardial infarction (AMI) remains unclear.
• Specifically, its effect on the risk of subsequent heart failure (HF) post-AMI requires further investigation.

Purpose of the Study:

• To investigate the association between peripheral thyroid hormone sensitivity, quantified by the FT3/FT4 ratio, and the incidence of HF and mortality in patients following AMI.

Main Methods:

• A retrospective cohort study involving 3648 inpatients diagnosed with AMI.
• Primary endpoint: HF during and after hospitalization. Secondary endpoints: all-cause and cardiovascular death post-hospitalization.
• Analysis included fully adjusted models, subgroup analyses, and mediation analysis using amino-terminal pro-B-type natriuretic peptide levels.

Main Results:

• Patients in the highest FT3/FT4 ratio quartile (Q4) exhibited a significantly reduced risk of in-hospital HF (44%) and out-of-hospital HF (37%) compared to the lowest quartile (Q1).
• Higher FT3/FT4 ratios were also associated with significantly lower risks of all-cause and cardiovascular death.
• Mediation analysis identified altered amino-terminal pro-B-type natriuretic peptide levels as a key mediator.

Conclusions:

• The FT3/FT4 ratio, reflecting thyroid hormone peripheral sensitivity, serves as an independent predictor of HF and mortality subsequent to AMI.
• This ratio offers valuable prognostic information for patients recovering from acute myocardial infarction.