Prevalence and predictors of postoperative pneumonia after coronary artery bypass grafting: a single-center registry study

Aim. To assess the prevalence and predictors of postoperative pneumonia (PP) after coronary artery bypass grafting (CABG) based on inhospital registry data.

Material and methods. This retrospective study of 925 patients who underwent elective CABG in 2017-2019 based on inhospital registry data. Combined intervention was performed in 11% of cases. PP was diagnosed according to national guidelines. Multivariate logistic regression was used to identify predictors. Preoperative, surgical, and postoperative variables were included in the association analysis.

Results. The incidence of PP was 8,7%. PP developed on day 5,5 [3; 8] (Me [Q25; Q75]) after CABG. Sex did not affect the risk. In univariate analysis, significant factors for PP were preoperative white blood cell (WBC) count, aortic cross-clamp time (ACCT), and maximum postoperative creatine phosphokinase (CPK) level. In the multivariate model, the independent nature of predictors was confirmed: preoperative leukocyte count (OR — odds ratio (odds ratio) =1,11; p=0,008), AC duration (OR=1,07; p=0,045), and postoperative CPK level (OR=1,04; p=0,018). Combined surgeries did not increase the risk.

Conclusion. PP is a serious complication of cardiac surgery, negatively affecting clinical outcomes and economic aspects of treatment. After CABG, PP was detected in 8,7% of cases in the examined cohort. There were following key predictors: preoperative WBC count, ACCT, and maximum postoperative CPK level. The obtained results indicate the possible benefit of monitoring individual inflammatory markers and minimizing ACCT for predicting and reducing the risk of pneumonia.

1. Bockeria LA, Milevskaya EB, Pryashnikov VV, et al. Serdechnososudistaya hirurgiya — 2022. Bolezni i vrozhdennye anomalii sistemy krovoobrashcheniya. M.: NMIC SSKH im. A.N. Bakuleva Minzdrava Rossii. 2023. p. 24. (In Russ.) ISBN 978-5-7982-0451-9.

2. Kaveshnikov VS, Kuzmichkina MA, Serebryakova VN. Predictors of long-term outcomes after surgical myocardial revascularization. Rational Pharmacotherapy in Cardiology. 2022; 18(6):710-6. (In Russ.) doi:10.20996/1819-6446-2022-12-09.

3. Wang D, Lu Y, Sun M, et al. Pneumonia After Cardiovascular Surgery: Incidence, Risk Factors and Interventions. Front Cardiovasc Med. 2022;9:911878. doi:10.3389/fcvm.2022.911878.

4. Nikitina TG, Pelekh DM, Filippkina TYu, et al. Analysis of early postoperative complications after correction of valvular heart defects in the elderly in conditions of artificial circulation. Byulleten' NTSSSKH im. A. N. Bakuleva RAMN "Serdechnososudistyye zabolevaniya". 2022;23(6):633-43. (In Russ.) doi:10.24022/18100694-2022-23-6-633-643.

5. Melly L, Torregrossa G, Lee T, et al. Fifty years of coronary artery bypass grafting. J Thorac Dis. 2018;10(3):1960-7. doi:10.21037/jtd.2018.02.43.

6. Kinlin LM, Kirchner C, Zhang H, et al. Derivation and validation of a clinical prediction rule for nosocomial pneumonia after coronary artery bypass graft surgery. Clin Infect Dis. 2010;50(4):493-501. doi:10.1086/649925.

7. Wang DS, Huang XF, Wang HF, et al. Clinical risk score for postoperative pneumonia following heart valve surgery. Chin Med J (Engl). 2021;134(20):2447-56. doi:10.1097/CM9.0000000000001715.

8. Zhidkova II, Shibanova IA, Ivanov SV, et al. Impact of gender and age on in-hospital outcomes of coronary artery bypass grafting. Atherosclerosis. 2018;14(4):14-24. (In Russ.) doi:10.15372/ATER20180402.

9. Kalashnikova TP, Arsenyeva YuA, Gorchakova MB, et al. Risk factors for the development of nosocomial pneumonia after aortic arch surgery. Complex Issues of Cardiovascular Diseases. 2023; 12(4):62-70. (In Russ.) doi:10.17802/2306-1278-2023-12-4-62-70.

10. Yao R, Liu X, He Y, et al. Low platelet count is a risk factor of postoperative pneumonia in patients with type A acute aortic dissection. J Thorac Dis. 2020;12(5):2333-42. doi:10.21037/jtd.2020.03.84.

11. Wang D, Abuduaini X, Huang X, et al. Development and validation of a risk prediction model for postoperative pneumonia in adult patients undergoing Stanford type A acute aortic dissection surgery: a case control study. J Cardiothorac Surg. 2022; 17(1):22. doi:10.1186/s13019-022-01769-y.

12. Pons S, Sonneville R, Bouadma L, et al. Infectious complications following heart transplantation in the era of high-priority allocation and extracorporeal membrane oxygenation. Ann Intensive Care. 2019;9(1):17. doi:10.1186/s13613-019-0490-2.

13. Kalashnikova TP, Arsenyeva YuA, Gorchakova MB, et al. Perioperative risk factors of nosocomial pneumonia after aortic arch surgery. Russian Journal of cardiology and cardiovascular surgery. 2024;17(4):364-9. (In Russ.) doi:10.17116/kardio202417041364.

14. Kalashnikova TP, Podoksenov YuK, Kamenshchikov NO, et al. Prevalence and risk factors for hospital-acquired pneumonia after on-pump cardiac surgery. Russian Journal of Cardiology. 2024;29(12):6094. (In Russ.) doi:10.15829/15604071-2024-6094.

15. Kravchenko IV, Podoksenov YuK, Tyo MA, et al. Prevention of respiratory complications in patients at risk of adverse respiratory events by perioperative nitric oxide delivery during cardiac surgery under cardiopulmonary bypass: a single-center prospective randomized study. Circulation Pathology and Cardiac Surgery. 2024;28(3):78-93. (In Russ.) doi:10.21688/1681-3472-2024-3-78-93.

16. Kalashnikova TP, Kamenshchikov NO, Podoksenov YuK, et al. High-dose inhaled nitric oxide therapy for nosocomial pneumonia following cardiac surgical procedures. Pulmonologiya. 2025;35(1):61-74. (In Russ.) doi:10.18093/0869-0189-2025-35-1-61-74.

17. Strobel RJ, Liang Q, Zhang M, et al. A Preoperative Risk Model for Postoperative Pneumonia After Coronary Artery Bypass Grafting. Ann Thorac Surg. 2016;102(4):1213-9. doi:10.1016/j.athoracsur.2016.03.074.

18. Wang D, Huang X, Wang H, et al. Risk factors for postoperative pneumonia after cardiac surgery: a prediction model. J Thorac. Dis. 2021;13(4):235-62. doi:10.21037/jtd-20-3586.

19. Jucá FG, Freitas FL, Goncharov M, et al. Difference Between Cardiopulmonary Bypass Time and Aortic Cross-Clamping Time as a Predictor of Complications After Coronary Artery Bypass Grafting. Braz J Cardiovasc Surg. 2024;39(2):e20230104. doi:10.21470/1678-9741-2023-0104.

20. Al-Sarraf N, Thalib L, Hughes A, et al. Cross-clamp time is an independent predictor of mortality and morbidity in low- and high-risk cardiac patients. Int J Surg. 2011;9(1):104-9. doi:10.1016/j.ijsu.2010.10.007.

21. Filsoufi F, Rahmanian PB, Castillo JG, et al. Predictors and early and late outcomes of respiratory failure in contemporary cardiac surgery. Chest. 2008;133(3):713-21. doi:10.1378/chest.07-1028.

22. Kilic A, Ohkuma R, Grimm JC, et al. A novel score to estimate the risk of pneumonia after cardiac surgery. J Thorac Cardiovasc Surg. 2016;151(5):1415-20. doi:10.1016/j.jtcvs.2015.12.049.

23. Mahmood E, Knio ZO, Mahmood F, et al. Preoperative asymptomatic leukocytosis and postoperative outcome in cardiac surgery patients. PLoS. One. 2017;12(9):e0182118. doi:10.1371/journal.pone.0182118.

24. Laffey JG, Boylan JF, Cheng DC. The systemic inflammatory response to cardiac surgery: implications for the anesthesiologist. Anesthesiology. 2002;97(1):215-52. doi:10.1097/00000542-200207000-00030.

25. Hashimoto Y, Futamura A. Association between Leukocyte Count and Age, Body Mass Index, and Lifestyle-related Factors: a Cross-sectional Study in Ningen Dock Examinees. Ningen Dock International. 2016;4(1):39-43. doi:10.11320/ningendockitn.4.1_39.

26. Chan-Yeung M, Abboud R, Buncio AD. Peripheral leucocyte count and longitudinal decline in lung function. Thorax. 1988;43(6):462- 6. doi:10.1136/thx.43.6.462.