Pro-inflammatory cytokines after different kinds of cardio-thoracic surgical procedures: is what we see what we know?
OBJECTIVE
Due to the combination of local trauma, extracorporeal circulation (ECC), and pulmonary and myocardial reperfusion, cardiac surgery leads to substantial changes in the immune system and possibly to post-operative complications. Procedures without ECC, however, have failed to demonstrate clear advantages. We hypothesized that ECC is far less important in this context than the reperfusion/reventilation of the lung parenchyma and the surgical trauma. We therefore conducted a prospective observational study to compare immune reactions after cardiac operations with those after thoracic surgery.


METHODS
Serum levels of pro-inflammatory interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-alpha as well as C-reactive protein (CRP), lipoprotein-binding protein (LBP) and procalcitonin (PCT) were measured pre-operatively (d0), at the end of the operation (dx), 6h after the operation (dx+), on the 1st (d1), 3rd (d3), and 5th (d5) post-operative days in 108 patients (pts) undergoing elective coronary artery bypass grafting (CAB) with ECC (n=42, CPB CAB), off-pump coronary artery bypass surgery (n=24, OP CAB) without ECC or thoracic surgery (n=42, TS).


RESULTS
After cardiac surgery (CS), IL-6 and IL-8 increased and reached a maximum on dx+. IL-6 returned to baseline values at d3, whereas IL-8 remained elevated until d5. No difference was found between OP CAB and CPB CAB patients. In the TS patients, IL-6 increased later (dx+) and absolute levels were lower than in the CS patients. No increase in IL-8 was noted in the TS patients. Due to the high variation in the results obtained in all three groups, there was no significant change in TNF-alpha. A comparison of TS, OP CAB, and CPB CAB revealed that the CS patients had higher levels on d0, dx, d3, and d5. Serum levels of CRP, LBP, and IL-2R increased from dx+ to d5 in all groups and reached maximum values on d3. Whereas we found no difference in CRP and IL-2R between the groups, LBP levels were significantly higher from dx+ to d3 after OP CAB. PCT was elevated from dx+ to d3 in all pts. Similar levels were noted for the TS and OP CAB patients. The CPB CAB patients showed the highest levels.


CONCLUSIONS
Surgical trauma and reperfusion injury appear to represent the predominant factors resulting in immunologic changes after cardiac surgery. Cardiopulmonary bypass (CPB) may be less important for immune response and acute-phase reactions than previously suspected. In addition, our data indicate a relationship between IL-6 synthesis and the degree of surgical trauma. IL-8 appears to be elevated only after cardiac surgery whereas PCT liberation depended on the use of ECC.
Franke
Axel
A
Department of Cardiovascular Surgery, Bundeswehr Central Hospital, Rübenacher Str.170, D 56072 Koblenz, Germany. dr.axel.franke@t-online.de
Lante
Wolfgang
W
Fackeldey
Volker
V
Becker
Horst P
HP
Kurig
Edmond
E
Zöller
Lothar G
LG
Weinhold
Christian
C
Markewitz
Andreas
A
D000368:Aged; D002097:C-Reactive Protein / Q000032:analysis; D002116:Calcitonin / Q000097:blood; D015740:Calcitonin Gene-Related Peptide; D002455:Cell Division / Q000276:immunology; D001026:Coronary Artery Bypass / Q000379:methods; D047549:Coronary Artery Bypass, Off-Pump / Q000379:methods; D016207:Cytokines / Q000097:blood*; D005112:Extracorporeal Circulation / Q000379:methods; D006331:Heart Diseases / Q000601:surgery; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology; D015850:Interleukin-6 / Q000097:blood; D016209:Interleukin-8 / Q000097:blood; D008213:Lymphocyte Activation / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology; D008875:Middle Aged; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood; D013899:Thoracic Neoplasms / Q000601:surgery; D019616:Thoracic Surgical Procedures / Q000379:methods*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
C000606589:CALCA protein, human; D016207:Cytokines; D015850:Interleukin-6; D016209:Interleukin-8; D011498:Protein Precursors; D014409:Tumor Necrosis Factor-alpha; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide