The Comparison of Postoperative Complications in Hypothyroid and Euthyroid Patients Undergoing Cardiac Surgery: A Retrospective Cohort Study

Background: Cardiac surgery plays a vital role in human health. Hypothyroidism is a common disorder that affects 4 - 10% of the world's population. One of the important challenges of cardiac surgery in hypothyroid patients is their perioperative management.

Objectives:

In this study, we determined the effects of hypothyroidism on complications after cardiac surgery. 

Methods: In this retrospective cohort study, patients who underwent cardiac surgery in Birjand, Iran, during 2016 - 2021 and had TSH > 5 μU/mL in adults ≤ 50 and TSH > 10 μU/mL in adults > 50 years old were included as the case group. Also, adults ≤ 50 with TSH 0.3 – 5 μU/mL and adults > 50 years old with TSH 0.3 – 10 μU/mL were included as the control group. The complications and outcomes of cardiac surgery were extracted from the patient files.

Results: This study involved 30 patients with hypothyroidism and 90 controls. The two study groups were comparable regarding gender, type of cardiac surgery, history of diabetes, hypertension, heart failure, myocardial infarction (MI), and dyslipidemia (P > 0.05). The frequency distribution of cardiac and pulmonary complications, delirium, acute kidney injury (AKI), sepsis, and mortality ratio was not significantly different between the two groups (P > 0.05); the mean systolic and diastolic blood pressure before and after the surgery, duration of mechanical ventilation, cardiopulmonary bypass time, aortic clamp time, duration of ICU hospitalization, and amount of use of dopamine, epinephrine, and norepinephrine were also similar (P > 0.05).

Conclusions: Hypothyroidism did not affect the frequency of complications and outcomes after cardiac surgery. Thus, achieving a euthyroid status in hypothyroid patients is unnecessary before cardiac surgery, and there is no need to postpone elective cardiac surgery until hypothyroidism is corrected.