Early and Long-Term Outcomes of Patients Undergoing Surgery for Native and Prosthetic Valve Endocarditis: The Role of Preoperative Neutrophil-to-Lymphocyte Ratio, Neutrophil-to-Platelet Ratio, and Monocyte-to Lymphocyte Ratio

<b>Background/Objectives:</b> Previous studies evaluated the prognostic role of hematological parameters in predicting outcome in patients with infective endocarditis (IE). However, only a few studies evaluated the role of hematological parameters in patients undergoing surgery for IE. The aim of this study was to review our 20-year experience with the treatment of native (NVE) and prosthetic (PVE) valve endocarditis and to evaluate the role of neutrophil-to-lymphocyte ratio (NLR), neutrophil-to-platelet ratio (NPR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), neutrophil-to monocyte ratio (NMR), and systemic inflammatory index (SII) on early and long-term outcomes of patients undergoing surgery for NVE and PVE. <b>Methods:</b> All adult patients undergoing surgery for NVE and PVE at our institution between January 2001 and December 2022 were included in the study. Preoperative NLR, NPR, PLR, MLR, NMR, and SII were calculated using hemograms with complete blood count. <b>Results:</b> During the study period, 503 patients, 371 (74%) males, median age 65 (52-73) years, underwent surgery for NVE (n = 337, 67%) or PVE (n = 166, 33%). Patients with PVE had significantly more aortic annulus abscess (95 (57%) vs. 51 (15%); <i>p</i> < 0.001), longer CPB (180 (131-235) vs. 105 (84-145) min; <i>p</i> < 0.001) and aortic cross-clamping times (129 (96-175) vs. 82 (64-114) min; <i>p</i> < 0.001), and received more aortic homografts (47 (28%) vs. 28 (9%); <i>p</i> < 0.001) and postoperative pacemaker implantation (25 (15%) vs. 20 (6%); <i>p</i> < 0.001 compared to patients with NVE. Preoperative NLR was 3.7 (2.4-6.1), NPR was 23 (16-37), PLR was 159 (106-210), NMR was 8.4 (6.6-12), MRL was 0.41 (0.29-0.62], and SII was 790 (485-1396). NLR, NPR, and MLR were significantly lower in patients with NVE compared to patients with PVE and in survivors compared to non-survivors. Overall mean survival time was 12.2 ± 0.5 years, with patients with NVE having better early and late survival compared to patients with PVE. Patients with preoperative NLR < 3.8, NPR < 30.9, and MLR < 0.4 had significantly better mean survival time compared to patients with preoperative NLR > 3.8, NPR > 30.9, and MLR > 0.4, respectively. <b>Conclusions:</b> In patients undergoing surgery for IE, preoperative higher NLR, NPR, and MLR are associated with increased early and long-term mortality.