Organ-specific biomarker analysis (Table 4)
Analysis of liver function biomarkers showed an AST count increase in both groups, but significantly higher in MIVT, together with raised ALT counts. In contrast, LDH levels increased significantly more in the sternotomy group compared to MIVT group.
Renal function biomarkers increased similarly in both groups as shown in Figure 5, corresponding with a decrease of GRF, but without reaching a statistically significant difference.
Myocardial damage assessed by troponin I and creatine kinase(CK) and creatine kinase MB(CK-MB) counts revealed no difference of postoperative troponin levels between MIVT and sternotomy. However, CK counts increased significantly more in the MIVT group than in the sternotomy group (MIVT: 89.74 to 933.02 U/l vs. sternotomy: 73.92 to 89.74 U/l; p=0.002). In contrast, CK-MB levels increased postoperatively in both groups, albeit based on samplings of only 44 patients.
Non-specific systemic inflammation was considered by leukocyte counts and C-reactive protein(CRP) levels. Leukocyte counts increased significantly more in MIVT compared to sternotomy. However, CRP counts raised significantly more from the first to second postoperative day in the sternotomy compared to the MIVT group(p<0.001)(Figure 6). Other hematologic biomarkers are listed in Table 4.
As red blood cell derivatives are confounded by intra- and postoperative transfusion, only the latter parameters are analyzed. Mediastinal drainage loss during the first 12 and 48 hours was higher in the MIVT group. No significant difference was found in the number of blood transfusions nor total blood transfusion volume.
The impact of the surgical approach on lung function was represented by the length of mechanical ventilation. No difference between groups was found concerning mechanical ventilation longer than 24 hours.