Levothyroxine Fails to Improve LVEF in Patients With Acute MI and Subclinical Hypothyroidism

Sarfaroj Khan 

July 28, 2020

Takeaway

Why this matters

  • Findings do not support screening for and subsequent treatment of subclinical hypothyroidism in patients with acute MI to preserve LV function.

Study design 

  • The Thyroxine in Acute Myocardial Infarction (ThyrAMI-2) trial included 95 patients with acute MI and subclinical hypothyroidism (mean age, 63.5 years; 76.6% were men and 69.1% had ST-segment elevation MI) randomly assigned to receive levothyroxine (n=46) and placebo (n=49).

  • Funding: National Institute for Health Research.

Key results

  • The mean LVEF at baseline and at 52 weeks was 51.3% and 53.8% in the levothyroxine vs 54.0% and 56.1% in the placebo group, respectively (adjusted between-group mean difference, 0.76%; 95% CI, −0.93 to 2.46%; P=.37).

  • No significant difference was observed between the levothyroxine and placebo groups in:

    • LV end-diastolic volume per body surface area (66.7 mL/m2 vs 70.4 mL/m2; adjusted between-group difference, −4.27 mL/m[95% CI, −9.03 to 0.49]);

    • LV end-systolic volume per body surface area (31.1 mL/m2 vs 31.4 mL/m2; −2.44 mL/m2 [95% CI, −5.46 to 0.58]);

    • cardiac output (4.1 L/min vs 4.6 L/min; −0.14 L/min [95% CI, −0.47 to 0.18]);

    • infarct size (5.8% vs 8.4%; 0.02% [95% CI, −1.34% to 1.38%]); and

    • LV mass (99.2 g vs 94.0 g; 1.97 g [95% CI, −4.43 to 8.37]).

  • There were 15 (33.3%) and 18 (36.7%) cardiovascular adverse events recorded in the levothyroxine and placebo groups, respectively.

 Limitations

  • The therapeutic efficacy of levothyroxine replacement may have been blunted because of the delay between coronary occlusion and initiation of therapy.

Jabbar A, Ingoe L, Junejo S, Carey P, Addison C, Thomas H, Parikh JD, Austin D, Hollingsworth KG, Stocken DD, Pearce SHS, Greenwood JP, Zaman A, Razvi S. Effect of Levothyroxine on Left Ventricular Ejection Fraction in Patients With Subclinical Hypothyroidism and Acute Myocardial Infarction: A Randomized Clinical Trial. JAMA. 2020;324(3):249-258. doi: 10.1001/jama.2020.9389. PMID: 32692386 View abstract. 

This clinical summary first appeared on Univadis, part of the Medscape Professional Network.

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