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

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 5, September/October 2021 246 AFRICA than that of plasma. In this study, we have shown that SCUBE1 may be present in pericardial fluid. SCUBE1 protein is a secreted glycoprotein from the vascular endothelium that forms oligomers tethered to the cell surface. That glycoprotein is a biomarker of platelet activation during inflammation and acute thrombotic complications. 10 The increase in plasma SCUBE1 levels of acute coronary syndrome patients was detectable in the plasma as early as six hours after the onset of symptoms and remained detectable for up to 84 hours. 10 It was found that acute coronary syndrome is an independent predictor of elevated plasma SCUBE1 concentrations. Smoking tends to increase plasma SCUBE1 concentrations. In addition, similar to the study done by Dai et al ., 10 in the subgroups of our study, there was no significant association of SCUBE1 levels between them. In the literature, plasma SCUBE1 levels have been used to diagnose acute mesenteric ischaemia, acute ischaemic stroke, congenital Congo haemorrhagic fever, Hashimoto’s thyroiditis, and renal and gastric cancer patients. 11-16 High levels of SCUBE1 were found both in STEMI and NSTEMI acute coronary syndrome patients. 17 In our study, SCUBE1 levels did not significantly increase in patients with coronary ischaemia. Pericardial fluid concentrations of some agents may increase in pathological cardiac diseases. Oikiwa et al . evaluated patients with normal baseline cardiac biomarkers and concluded that creatine kinase is useful in excluding procedure-relatedmyocardial infarction. 3 Göber showed early troponin T levels may be useful in follow up of coronary bypass patients and concluded that troponin T may predict clinically relevant complications. 4 Fellahi et al . investigated short- and long-term prognostic value of cardiac troponin I and stated that a high cardiac troponin I level was associated with mortality after CABG surgery. 18 Pericardial SCUBE1 levels were not effective in predicting mortality in patients undergoing elective CABG surgery and did not significantly increase in patients with coronary artery disease. Pericardial SCUBE1 values ​of patients with temporary cardiac pacing due to peri-operative bradycardia were found to be significantly higher than those of other patients. It was also found that patients with intra-aortic balloon pump had significantly higher pericardial SCUBE1 levels. We have shown that in patients with elective CABG surgery, we may be able to predict the need for postoperative intra-aortic balloon pump support and the need for temporary cardiac pacing due to peri-operative bradycardia, as the SCUBE1 levels in the pericardial fluid of those patients were significantly higher. We could not compare our results with other studies because there is no literature on SCUBE1 levels in pericardial fluid. Limitations The limitation of our study was that, for the analysis of SCUBE1 levels, pericardial fluid samples were taken from angiographically coronary artery disease-free patients who underwent open-heart surgery. For control subjects, it was practically impossible to retrieve pericardial fluid specimens from healthy volunteering adults. It takes 15 to 20 minutes to get results with the ELISA test, but we could not find a correlation between high pericardial SCUBE1 levels and major postoperative complications, including postoperative early mortality. Conclusions This is the first study in the literature published on normal levels of SCUBE1 in pericardial fluid. In our study, mean SCUBE1 values in samples taken from pericardial fluid of open-heart surgery patients without ischaemic coronary artery disease were 0.049 ± 0.061 ng/ml. SCUBE1 levels in pericardial and arterial blood samples were similar in patients with or without coronary ischaemia. High levels of SCUBE1 in pericardial fluid in patients undergoing CABG surgery may help predict the need for postoperative intra-aortic balloon pump support and the need for temporary cardiac pacing due to peri-operative bradycardia. This article was presented at the 15th meeting of the Turkish Society of Cardiovascular Surgery held in Antalya, Turkey, between 26 and 29 October 2018. References 1. Chalmers J, Pullan M, Fabri B, McShane J, Shaw M, Mediratta N, et al . Validation of EuroSCORE II in a modern cohort of patients undergo- ing cardiac surgery. Eur J Cardiothorac Surg 2013; 43 (4): 688–694. 2. Barili F, Pacini D, D’Ovidio M, Dang NC, Alamanni F, Di Bartolomeo R, et al . The impact of EuroSCORE II risk factors on prediction of long-term mortality. Ann Thorac Surg 2016; 102 (4): 1296–1303. 3. Oikawa FTC, Hueb W, Nomura CH, Hueb AC, Villa AV, da Costa LMA, et al . Abnormal elevation of myocardial necrosis biomarkers after coronary artery bypass grafting without established myocardial infarction assessed by cardiac magnetic resonance. J Cardiothorac Surg 2017; 12 (1): 122. 4. Göber V, Hohl A, Gahl B, Dick F, Eigenmann V, Carrel TP, et al . Early troponin T and prediction of potentially correctable in-hospital complications after coronary artery bypass grafting surgery . PLoS One 2013; 8 (9): e74241. 5. Özkan G, Ulusoy S, Mente ş e A, Karahan SC, Cansiz M. New marker of platelet activation, SCUBE1, is elevated in hypertensive patients. Am J Hypertens 2013; 26 (6): 748–753. 6. Günaydın M, Turkmen S, Sahin A, Sumer A, Mente ş e A, Türedi S, et al . The diagnostic value of SCUBE1 levels in acute ischemic stroke. Turk J Biochem 2014; 39 (1): 107–112. 7. Tu CF, Su YH, Huang YN, Tsai MT, Li LT, Chen YL, et al . Localization and characterization of a novel secreted protein SCUBE1 in human platelets. Cardiovasc Res 2006; 71 (3): 486–495. 8. Yang RB, Ng CK, Wasserman SM, Colman SD, Shenoy S, Mehraban F, et al . Identification of a novel family of cell-surface proteins expressed in human vascular endothelium. J Biol Chem 2002; 277 : 46364–46373. 9. Spodick D. Macrophysiology, microphysiology, and anatomy of the pericardium: A synopsis. Am Heart J 1992; 124 : 1046–1051. 10. Dai DF, Thajeb P, Tu CF, Chiang FT, Chen CH, Yang RB, et al . Plasma concentration of SCUBE1, a novel platelet protein, is elevated in patients with acute coronary syndrome and ischemic stroke. Am College Cardiol 2008; 51 (22): 2173–2180. 11. Turkmen S, Mentese S, Mentese A, Sumer AU, Saglam K, Yulug E, et al . The value of signal peptide‐CUB‐EGF domain‐containing protein 1 and oxidative stress parameters in the diagnosis of acute mesenteric ischemia. Acad Emergency Med 2013; 20 (3): 257–264. 12. Turkmen S, Eryigit U, Karaca Y, Mentese A, Sumer UA, Yulug E, et al . Diagnostic value of plasma signal peptide-CUB-EGF domain-contain- ing protein-1 (SCUBE1) in an experimental model of acute ischemic stroke . Am J Emerg Med 2015; 33 (2): 262–265.