title: Nonthyroidal illness syndrome in off-pump coronary artery bypass grafting.
abstract: BACKGROUND
  Cardiopulmonary bypass (CPB) is an established cause of nonthyroidal illness syndrome (NTIS). Off-pump coronary artery bypass (OPCAB) has been reported to be less invasive than coronary artery bypass grafting (CABG) with CPB. We prospectively evaluated thyroid metabolism in OPCAB patients.
  
  
  METHODS
  We analyzed free thyroid hormones (FT3 and FT4), thyroid-stimulating hormone (TSH), and reverse T3 (rT3) in 20 consecutive patients undergoing CABG surgery. Nine patients underwent CABG with CPB, and 11 underwent OPCAB. Blood samples were taken on admission, on the day of surgery (7:30 AM), after sternotomy, at the end of the operation, and at 2, 6, 12, 24, 36, 48, 72, 96, 120, and 144 hours postoperatively. The concentrations of FT3, FT4, and TSH were determined on each sample. Reverse T3 concentration was measured in 10 patients up to 48 hours and at 144 hours postoperatively.
  
  
  RESULTS
  Baseline, operative, and postoperative variables were similar in the two groups. FT3 concentration dropped significantly (p < 0.0001), reaching its lowest value 12 hours postoperatively. There were no significant differences between CPB and OPCAB patients. FT4 varied significantly in both groups (p < 0.0001), but remained in the normal range. TSH variation was not significant. rT3 concentration rose significantly (p = 0.0002) in both groups, peaking 24 hours after surgery. CONCLUSIONS. OPCAB induces a NTIS similar to that observed after CPB, probably due to the inhibition of T4 conversion to T3. This finding suggests that NTIS is a nonspecific response to stress. CPB should not be considered as the sole trigger of NTIS in cardiac surgical patients.
authors.affiliation: Unità Operativa di Cardiochirurgia Adulti, Ospedale G. Pasquinucci, Massa, Italy. cerillo@ifc.cnr.it
authors.forename: Alfredo Giuseppe
authors.initials: AG
authors.lastname: Cerillo
authors.forename: Laura
authors.initials: L
authors.lastname: Sabatino
authors.forename: Stefano
authors.initials: S
authors.lastname: Bevilacqua
authors.forename: Pier Andrea
authors.initials: PA
authors.lastname: Farneti
authors.forename: Maria
authors.initials: M
authors.lastname: Scarlattini
authors.forename: Francesca
authors.initials: F
authors.lastname: Forini
authors.forename: Mattia
authors.initials: M
authors.lastname: Glauber
mesh_terms: D000368:Aged; D001026:Coronary Artery Bypass / Q000009:adverse effects* / Q000379:methods*; D005067:Euthyroid Sick Syndromes / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011446:Prospective Studies; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D013997:Time Factors; D014284:Triiodothyronine / Q000097:blood; D014285:Triiodothyronine, Reverse / Q000097:blood
chemical_list: D014284:Triiodothyronine; D014285:Triiodothyronine, Reverse; D013972:Thyrotropin; D013974:Thyroxine