Thyroid Hormone Replacement After Coronary Artery Bypass Grafting for Patients With Subclinical Hypothyroidism

Seoul National University Bundang Hospital338 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

338

Conditions

Subclinical Hypothyroidism

Interventions

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.

Eligibility

Sex: ALLMin age: 19 YearsMax age: 90 Years

Medical Language ↔ Plain English

Eligibility Criteria * Adults aged 19 to 90 years. * Patients scheduled to undergo coronary artery bypass graft (CABG) surgery. * Subclinical hypothyroidism (SCH), defined as a normal free thyroxine (free T4) level and a thyroid-stimulating hormone (TSH) level greater than 4 μIU/mL, based on testing performed within 31 days prior to surgery. Exclusion Criteria: * 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)

Outcomes

Primary Outcomes

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.