Procalcitonin levels after different types of conventional thoracic surgery.

BACKGROUND: Procalcitonin (PCT) is currently discussed as an indicator of postoperative complications following thoracic surgery. Serum levels of PCT are different after thoracoscopic and conventional surgical approaches. We conducted this study to test the hypothesis that different types of conventional thoracic surgery are associated with different postoperative serum levels of acute-phase proteins or pro-inflammatory mediators. METHODS: Serum levels of interleukin (IL)-6, C-reactive protein (CRP), lipoprotein-binding protein (LBP) and PCT were measured preoperatively (pre), immediately after surgery (0 h), 6 hours after surgery (6 h), and on the 1st (d1), 3rd (d3) and 5th (d5) postoperative days in 48 patients undergoing elective conventional pneumonectomy (n = 6), lobectomy (n = 20) or wedge resection (n = 22). RESULTS: In all study groups, IL-6 and PCT increased after surgery, peaking at 6 h and on d1, respectively. The time courses of IL-6, CRP, LBP and PCT release were not influenced by the type of surgical procedure. All parameters increased more markedly after lobectomy and wedge resection than after pneumonectomy. CONCLUSIONS: Surgical trauma and lung ischaemia/reperfusion injury could be the main factors determining the release of IL-6 and PCT after surgery. From an immunological point of view, pneumonectomy is less severe than wedge resection or lobectomy in terms of tissue injury. Different types of conventional thoracic surgery are associated with differences in postoperative PCT and IL-6 synthesis. For this reason, expected ranges of PCT and IL-6 levels should be established for the various surgical procedures before these parameters can be used as indicators of postoperative complications.

Immunoglobulin levels and lymphocyte subsets following cardiac operations: further evidence for a T-helper cell shifting.

BACKGROUND: Recent data indicate that cardiac surgery with cardiopulmonary bypass (CPB) results in an imbalance of T-helper cell subsets towards the anti-inflammatory pathway mediating humoral immune response. However, little is known about immunoglobulin levels as an important part of humoral immune response after CPB. Therefore, the objectives of this study were 1) to elucidate the effects of CPB on perioperative immunoglobulin levels, and 2) to find out if alterations in lymphocyte subsets are related to these findings. METHODS: Blood samples from 83 patients undergoing elective cardiac operation were taken preoperatively (d0), on the first (d1), third (d3), and fifth day (d5) after operation. Levels of immunoglobulin (Ig) E, IgM, and IgG, including the subclasses IgG 1 - 4, were measured. IgG2/IgE-ratio was used as indicator for TH1/TH2 shifting, and production of tetanus antibodies (AB) was investigated as an in vivo parameter of humoral immune reaction. The number and percentage of T- and B-lymphocyte subsets were assessed in a subgroup of 50 patients to answer the second question. RESULTS: Clinically, no mortality or major morbidity were observed. IgE levels did not change until d3 and increased significantly on d5. In contrast, both IgG and IgM levels decreased significantly on d1. While IgM returned to baseline (BL) on d5, IgG levels remained below BL until d5. IgG2/IgE-ratio decreased significantly on d1, reached its nadir on d3 and remained depressed until d5. The number of T-lymphocytes decreased on d1 as well as the number of B-cells. T-cells returned to BL on d5, B-cells on d3. However, while the percentage of T-cells decreased on d1, the percentage of B-cells increased. The percentage of T-cells returned to BL on d3, and B-cell percentage returned to BL on d5. Tetanus AB production did not change until d5 when it increased significantly. CONCLUSIONS: 1) Increase of IgE and tetanus AB production indicate that humoral immune response is not affected by CPB, but possibly even enhanced. The relative increase of B-cells is in line with this hypothesis. 2) Postoperative changes in immunoglobulin levels provide further evidence for a TH1/TH2-shifting. 3) The transient deficit in IgM-and IgG levels did not result in clinically adverse events. Thus, therapeutic intervention appears not to be required.

Alterations of cell-mediated immunity following cardiac operations: clinical implications and open questions.

Cardiac surgery with cardiopulmonary bypass (CPB) is known to induce an immune response whose nature has been increasingly elucidated during the recent decade. Clinically, patients usually show two to three of the four symptoms, which define the so-called systemic inflammatory response syndrome (SIRS). In addition, all parameters of the innate, nonspecific immune system, e.g., polymorphonuclear cells, elastase, and complement, are activated. This also applies to the proinflammatory mediators interleukin (IL)-1beta, -6, and -8, and tumor necrosis factor (TNF)-alpha. Within the adaptive, specific immune system, a decrease of T lymphocytes and T helper (TH) cells is observed, whereas suppressor/ cytotoxic T cells and B cells appear to be nearly unaffected. Cytokine measurements provide more detailed information: IL-2 and IL-12, which are important for the activation of the type-1 TH-cell (TH1)-mediated immune response, are depressed following cardiac operation. In contrast, IL-10 and transforming growth factor-beta essential to TH2-mediated humoral or anti-inflammatory immune response, are upregulated. In vivo tests, e.g., delayed type hypersensitivity skin reaction and tetanus antibody production, confirm the polarization of the adaptive immune response towards the TH2 pathway. However, all these alterations usually do not result in clinical adverse events. Therefore, more information is needed about the immune response of patients at high preoperative risk or with serious perioperative complications to find out whether clinically relevant events are correlated to alterations of immune response. For this purpose, more readily available, standardized methods for immunologic monitoring appear highly desirable.

Endothelialization of cardiac valve bioprostheses.

The main disadvantage of implanted xenograft valves used in cardiac surgery is their poor clinical long-term result, due to early tissue degeneration. In order to improve the performance of such glutaraldehyde fixed bioprostheses, a biological coating with viable endothelial cells was suggested. Therefore, glutaraldehyde preserved bovine pericard patches, as well as commercially available xenograft valves, were lined using human venous endothelial cells or microvascular cells from the subcutaneous fat tissue. Before cells were transplanted into their new environment, grafts were treated with an amino acid solution in order to neutralize the cytotoxic effect of free aldehydes, and precoated with fibronectin-heparin and basic fibroblast growth factor (bFGF) or endothelial cell growth supplement (ECGS) in order to enhance cell proliferation. Coated specimens were kept in culture conditions for a further seven days. Proliferation of transplanted cells was verified by an increase of activation following 3H-thymidine incorporation, while the maintained metabolic cell activity was demonstrated via Prostacycline (PGI2) measurement. Morphology was evaluated by means of scanning electron microscopy (SEM). As evaluated by the beta-Counter, 7 ng/ml bFGF (288,727 +/- 39,668 counts on day 4) substantially enhanced cell proliferation after seeding, opposed to the stimulation with 30,000 ng/ml ECGS (91,924 +/- 1129 counts on day 4), (p < 0.001). The PGI2 release of transplanted cells was stimulated with 25 microM Na arachidonic acid by the factor 2.6 +/- 0.3 and inhibited with 5 mM acetylsalicylic acid by the factor 0.7 +/- 0.2 on day 4 when compared with the basic level.(ABSTRACT TRUNCATED AT 250 WORDS)