Impact Of Overt Hypothyroidism On Outcomes Of Coronary Bypass Surgery

Background:The association between preoperative overt hypothyroidism and early outcomes after coronary artery bypass grafting(CABG)is unclear.This study aimed to evaluate the influence of overt hypothyroidism on the outcomes of CABG.Methods:The series included 189 overt hypothyroid patients who underwent CABG at Fuwai Hospital.These patients were 1:4 matched with 737 euthyroid patients using propensity score matching.The early postoperative outcomes were compared.Results:After CABG,there was no difference in mortality between the two groups(0%in the overt hypothyroid group and 0.3%in the euthyroidism group;P=1.00).There was no difference in the incidence of postoperative atrial fibrillation between the two groups(19.8%in the overt hypothyroid group and 19.8%in the euthyroidism group).The incidences of impaired wound healing,reintubation,and the total complications were higher in overt hypothyroid patients than euthyroid patients(11.8%vs.0.9%,p<0.001;2.1%vs.0.4%,p=0.03;39.6%vs.30.3%,p=0.015,respectively).Multivariate analysis showed overt hypothyroidism was significantly associated with the occurrence of impaired wound healing(odds ratio[OR]=12.29,p<0.001),reintubation(OR=5.71,p=0.047),and the total complications(OR=1.31,p=0.049).The OR of the total complications was 1.43(p=0.03)in overt hypothyroid patients with abnormal thyroid-stimulating hormone compared with euthyroid patients.The proportions of the use of dopamine,adrenaline,milrinone,and dobutamine in overt hypothyroid patients were higher than euthyroid patients(75.4%vs.67.6%,p=0.038;10.7%vs.6.1%,p=0.028;3.2%vs.0.3%,p=0.001;4.8%vs.1.2%,p=0.004,respectively).The total duration of inotropic support and mechanical ventilation time in overt hypothyroid patients were longer than euthyroid patients(median duration:4 days vs.3 days,p=0.003;17 hours vs.15 hours,p<0.001,respectively).Conclusions:Compared with euthyroidism,overt hypothyroidism is not associated with an increased risk of mortality or atrial fibrillation in patients undergoing CABG.It is associated with a higher incidence of postoperative complications,stronger postoperative inotropic support,and longer mechanical ventilation time.Background: Subclinical hypothyroidism(SCH)is characterized by an elevated thyroid-stimulating hormone and normal free thyroxine.This study aimed to evaluate the influence of SCH on the recovery of patients after coronary artery bypass grafting(CABG).Methods: From January 2015 to December 2018,548 SCH patients and 6718 euthyroid patients who underwent CABG were identified.Propensity score matching was used to create two cohorts with similar baseline characteristics(n=545 in each group).The early postoperative outcomes were compared.Results: After propensity score matching,baseline characteristics were similar in the two groups.After CABG,there was no difference in mortality between the two groups(0.2% in the SCH group and 0% in the euthyroidism group;P=1.00).There was no difference in the incidence of postoperative atrial fibrillation between the two groups(20.4% in the SCH group and 20.6%in the euthyroidism group;odds ratio 0.99;95% confidence interval 0.74 to 1.33;P=0.94).Subgroup analyses did not indicate effect in any category of patients.The proportions of the use of dopamine and noradrenaline in the SCH group were higher than those in the euthyroid patients(76.7% vs.68.6%,p=0.003;56.5% vs.49.0%,p=0.01,respectively).The total duration of inotropic support in the SCH group was longer than that in the euthyroid patients(median duration: 4 days vs.3 days,p=0.002).The mechanical ventilation time was longer in the SCH group than in the euthyroid group(median time: 17 hours vs.16 hours,p<0.001).The incidence of impaired wound healing was higher in the SCH group than in the euthyroid group(3,7%vs.1.1%,p=0.005).Conclusions: Compared with euthyroidism,SCH is not associated with an increased risk of mortality or atrial fibrillation in patients undergoing CABG.It is associated with longer postoperative duration of inotropic support,mechanical ventilation time,a higher proportion of inotropic drug usage and impaired wound healing.