NCT07380854

Brief Summary

The goal of this clinical trial is to find out whether levothyroxine reduces complications and improves the prognosis of patients with subclinical hypothyroidism (SCH) undergoing coronary artery bypass grafting (CABG). The main questions this study aims to answer are:

  • Does levothyroxine reduce major adverse cardiovascular events (MACE), including cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, and new arrhythmias, in SCH patients undergoing CABG? Researchers will compare patients who take levothyroxine with those who do not. Participants will:
  • Be randomly assigned to either receive levothyroxine or not
  • Start the medication one day before surgery if assigned to the treatment group.
  • Have regular follow-up visits to check thyroid function and cardiovascular events for up to five years after surgery.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
338

participants targeted

Target at P75+ for not_applicable

Timeline
132mo left

Started Feb 2022

Longer than P75 for not_applicable

Geographic Reach
1 country

1 active site

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress28%
Feb 2022Feb 2037

Study Start

First participant enrolled

February 27, 2022

Completed
3.9 years until next milestone

First Submitted

Initial submission to the registry

January 15, 2026

Completed
18 days until next milestone

First Posted

Study publicly available on registry

February 2, 2026

Completed
6.1 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

February 26, 2032

Expected
5 years until next milestone

Study Completion

Last participant's last visit for all outcomes

February 26, 2037

Last Updated

February 2, 2026

Status Verified

December 1, 2025

Enrollment Period

10 years

First QC Date

January 15, 2026

Last Update Submit

January 24, 2026

Conditions

Subclinical Hypothyroidism

Keywords

subclinical hypothyroidismcoronary artery bypass graftingthyroid hormoneslevothyroxine

Outcome Measures

Primary Outcomes (1)

  • A composite of MACE within 4months after surgery

    A composite of major adverse cardiovascular events (MACE), including cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, and the occurrence of new arrhythmias assessed within 4 months after CABG.

    within 4months after surgery

Secondary Outcomes (12)

  • Number of participants who experience cardiovascular death within 4 months after surgery

    within 4months after surgery

  • Number of participants who experience nonfatal myocardial infarction within 4 months after surgery

    within 4months after surgery

  • Number of participants who experience nonfatal stroke within 4 months after surgery

    within 4months after surgery

  • Number of participants who experience new arrhythmia within 4 months after surgery

    within 4months after surgery

  • A composite of MACE within 1 year after surgery

    within 1 year after surgery

  • +7 more secondary outcomes

Study Arms (2)

LT4 group

EXPERIMENTAL

Participants in this group will receive levothyroxine

Drug: levothyroxine

Control group

NO INTERVENTION

Participants in this group will not receive levothyroxine

Interventions

levothyroxineDRUG

Intervention description: Participants assigned to the LT4 group will begin receiving levothyroxine the day before CABG. The initial dose is 25 μg once daily, or 12.5 μg for participants weighing less than 60 kg. The dose will then be adjusted based on thyroid function test results to achieve target TSH levels of 0.4-2.0 μIU/mL.

LT4 group

Eligibility Criteria

Age19 Years - 90 Years
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64), Older Adult (65+)

You may not qualify if:

  • Patients who underwent repeat or emergency CABG surgery
  • Use of LT4 within the previous 4 weeks
  • Use of antithyroid drug use (propylthiouracil, methimazole, or carbimazole) within the previous 3 months
  • Severe comorbid conditions with a life expectancy of less than 1 year (e.g. advanced malignancy)

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Department of Internal Medicine, Seoul National University Bundang Hospital

Seongnam-si, 13620, South Korea

RECRUITING

MeSH Terms

Interventions

Thyroxine

Intervention Hierarchy (Ancestors)

Thyroid HormonesHormonesHormones, Hormone Substitutes, and Hormone AntagonistsAmino Acids, AromaticAmino Acids, CyclicAmino AcidsAmino Acids, Peptides, and Proteins

Central Study Contacts

Min Joo Kim, Professor

CONTACT

+82-31-787-7855chorong24@gmail.com

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
NONE
Purpose
TREATMENT
Intervention Model
PARALLEL
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Professor of Internal Medicine

Study Record Dates

First Submitted

January 15, 2026

First Posted

February 2, 2026

Study Start

February 27, 2022

Primary Completion (Estimated)

February 26, 2032

Study Completion (Estimated)

February 26, 2037

Last Updated

February 2, 2026

Record last verified: 2025-12

Data Sharing

IPD Sharing
Will not share

Locations

KR(1)