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Thyroid Hormones Predict Readmission After Aortic Surgery

Researchers theorized that thyroid hormone levels might provide valuable predictive information.


 

Thoracic endovascular aortic repair (TEVAR) is a “young technology with several unknowns,” say researchers from Shantou University Medical College, and Wuhan Asia Heart Hospital, both China. One of those unknowns is the risk factors for prognosis after TEVAR.

After all, thyroid hormones are critical to many areas of heart health, such as vascular remodeling; hypothyroidism can aggravate hypertension; and low levels of free thyroxine (FT4) influence arterial stiffness and C-reactive protein. In spite of the many links, however, the relationship between subclinical hypothyroidism and cardiovascular disease has not been fully elucidated, the researchers say. They conducted a study to evaluate whether thyroid hormones predicted early (30 days) and mid-term (12 months) aorta-related adverse events (AEs), such as death, progression of aortic disease, organ failure, or lower limb ischemia; and aorta-related readmissions.

In their study, 338 patients were stratified according to their levels of FT4 before undergoing TEVAR. Of the enrolled patients, 288 were followed up at 12 months for readmission; 292 were followed up on AEs.

Patients with low normal levels of FT4 had a greater risk of readmission after thoracic endovascular aortic repair. Within 30 days, the incidence of AEs and readmission were 2.7% and 4.1%; within 12 months, 8.9% and 13.5%. After the researchers adjusted for confounders, the patients with the lowest FT4 quartile were at significantly greater risk for readmission than those in the highest-quartile group, at both early and mid-term follow-up.

The same did not hold true for AEs. The researchers say this is not uncommon in studies of predictors of AEs and readmission: Factors that are weak predictors of readmission tend to be strong predictors of AEs, and vice versa.

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