Cardiovascular Journal of Africa: Vol 32 No 5 (SEPTEMBER/OCTOBER 2021)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 5, September/October 2021 244 AFRICA patients under 18 years of age, those with chronic renal failure, those operated on under emergency conditions, those with blood mixed with pericardial fluid during the surgery, participants with inadequate pericardial fluid, or who were not willing to take part in the study were excluded. All patients were in a stable condition pre-operatively. Group 1 consisted of patients who underwent coronary angiography due to unstable angina pectoris (USAP) and underwent CABG surgery ( n = 49). Group 2 consisted of patients who underwent coronary angiography due to non-ST-elevation myocardial infarction (NSTEMI) and underwent CABG surgery ( n = 50). Group 3 consisted of patients who underwent coronary angiography due to ST-elevation myocardial infarction (STEMI) and underwent CABG surgery ( n = 54). Group 4 consisted of patients who underwent open-heart surgery due to non-coronary conditions ( n = 31) [aortic valve replacement ( n = 13), mitral valve replacement ( n = 10), aortic and mitral (double) valve replacement ( n = 4), atrial myxoma ( n = 2) and atrial septal defect ( n = 2)]. All patients in group 4 had normal coronary angiograms. No changes were made in the surgical methods or steps during the study. All patients in the study groups were operated on under cardiopulmonary bypass. Complete revascularisation was aimed for in all coronary cases. Demographic data related to patients in the study groups, including age, gender, hypertension, diabetes mellitus, smoking habits, chronic obstructive pulmonary disease, left main coronary artery disease, operative data and postoperative complications were noted carefully. Pericardial fluid samples of 2–5 cm 3 in volume were taken with a syringe by the cardiac surgeon after median sternotomy and incising the pericardium. Before heparinisation, a simultaneous peripheral arterial blood sample was withdrawn. Samples were transferred to Vacutainer sterile tubes (Plymouth, UK) and immediately centrifuged at 3 600 rpm for 15 minutes. Samples were stored at –80°C. SCUBE1 levels were determined from the serum and pericardial fluid with an enzyme-linked immunosorbent assay kit (catalogue no CSBE15005 h, Cusabio Biotech Co, Wuhan, Hubei, PR China) and the results were compared. Statistical analysis Statistical analysis was performed by a biostatistician using the SPSS v 22 (IBM Corp, Armonk, NY, USA) software for windows. Descriptive statistics are expressed as median and minimum–maximum with mean ± standard deviation for continuous variables, and frequency and percentage for categorical variables. The Kolmogorov–Smirnov and Shapiro tests were conducted initially in order to ensure that the variable distribution matched with the normal distribution. In order to ensure that the continuous and categorical variables were in accordance with the normal distribution, the non-parametric independent t -test was used in variables with two subgroups, one-way ANOVA was used in variables with more than two subgroups, and continuous variables without normal distribution were compared using the Mann–Whitney U -test. In addition to this, Pearson’s correlation analysis was used when comparing continuous variables with continuous variables. A value of p < 0.05 was set as the level of statistical significance. Results In our study, SCUBE1 levels in pericardial fluid samples of group 4 patients were 0.049 ± 0.061 (0–0.23) ng/ml. SCUBE1 levels in the arterial samples were higher than that in pericardial fluid in all groups. Demographic features of the patients are shown in Table 1. The groups were found to be similar when assessed in the context of pre-operative demographic data. Operative outcomes, postoperative morbidity and mortality, and mean distributions of pericardial and arterial SCUBE1 are shown in Table 2. There was no significant difference between total bypass time, cross-clamp time, number of bypass grafts, postoperative stroke, prolonged intensive care unit stay and mortality rate. Although SCUBE1 levels in both arterial and pericardial fluid were higher in groups 1, 2 and 3 compared to group 4, no statistically significant difference was found. There was no difference between pericardial ( p = 0.350) and arterial ( p = 0.796) SCUBE1 levels of USAP patients (group 1) and non-coronary open-heart surgery patients (group 4). There was no difference between pericardial ( p = 0.185) and arterial ( p = 0.346) SCUBE1 levels of NSTEMI patients (group 2) and non-coronary open-heart surgery patients (group 4). There was no difference between pericardial ( p = 0.338) and arterial ( p = 0.534) SCUBE1 levels of STEMI patients (group 3) and non-coronary open-heart surgery patients (group 4). Table 1. Demographic features of the patients Demographics Group 1 Group 2 Group 3 p -value Gender (male/female) 27/22 36 /14 47/7 0.045 Age (years) 66.9 ± 8.4 62 ± 9.7 62.6 ± 8.3 0.012 Hypertension, n (%) 34 (69.4) 34 (68) 35 (64.8) 0.878 Diabetes mellitus, n (%) 21 (42.9) 20 (40) 20 (37) 0.834 Pre-operative atrial fibrillation, n (%) 28 (57.1) 23 (46) 26 (48.1) 0.500 Smoking, n (%) 26 (53.1) 33 (66) 39 (72.2) 0.121 Peripheral arterial occlu- sive disease, n (%) 8 (16.3) 7 (14) 6 (11.1) 0.743 Chronic obstructive pulmonary disease, n (%) 1 (2) 4 (8) 6 (11.1) 0.198 Left main coronary artery disease, n (%) 26 (53.1) 17 (34) 21 (28.9) 0.136 Ejection fraction (%) 52.8 ± 9.1 54.4 ± 9 57.9 ± 8.6 0.008 HDL-C (mg/dl) (mmol/l) 40.1 ± 8.7 (1.04 ± 0.23) 38.9 ± 7.3 (1.01 ± 0.19) 43.9 ± 10.3 (1.14 ± 0.27) 0.127 LDL-C (mg/dl) (mmol/l) 108.2 ± 25.9 (2.80 ± 0.67) 120.9 ± 45.1 (3.13 ± 1.17) 118 ± 37.9 (3.06 ± 0.98) 0.096 HDL-C: high-density lipoprotein cholesterol; LD-CL: low-density lipoprotein cholesterol. Table 2. Operative outcomes, postoperative morbidity and mortality, and mean distributions of pericardial and arterial SCUBE1 Variables Group 1 Group 2 Group 3 p -value Total bypass time (min) 93.2 ± 31.4 85.9 ± 31.4 90.8 ± 24.5 0.080 Cross-clamp time (min) 47 ± 20.7 46.8 ± 19.3 47.7 ± 13.5 0.463 Number of grafts 3.1 ± 0.8 2.9 ± 0.8 3.1 ± 0.9 0.371 Intra-aortic balloon pump, n (%) 1 (2) 0 (0) 3 (5.6) 0.198 Postoperative stroke, n (%) 7 (14.3) 3 (6) 4 (7.4) 0.309 Revision for postoperative bleeding, n (%) 0 (0) 1 (2) 1 (1.9) 0.619 Temporary cardiac pacing, n (%) 2 (4.1) 0 (0) 1 (1.9) 0.341 Prolonged intensive care unit stay (> 48 hours), n (%) 14 (28.6) 7 (14) 6 (11.1) 0.048 Exitus, n (%) 2 (4.1) 0 (0) 1 (1.9) 0.341 Pericardial SCUBE1 (ng/ml) 0.124 ± 0.272 0.177 ± 0.301 0.179 ± 3.453 0.775 Arterial SCUBE1 (ng/ml) 6.531 ± 6.457 8.537 ± 8.169 6.975 ± 6.566 0.632