Table 2 Demographic and clinical variables before and after propensity score matching
Variables | Before PSM | After PSM | ||||
|---|---|---|---|---|---|---|
The gelatin group (n = 1921) | The HES group (n = 12,522) | P | The gelatin group (n = 1880) | The HES group (n = 1880) | P | |
Female, n (%) | 523 (27.2) | 3497 (27.9) | 0.523 | 506 (26.9) | 484 (25.7) | 0.985 |
Age, years, mean ± SD | 57.3 ± 10.8 | 57.3 ± 10.8 | 0.839 | 57.3 ± 10.7 | 57.4 ± 10.6 | 0.753 |
BMI, kg/m2, mean ± SD | 25.25 ± 3.27 | 25.08 ± 3.25 | 0.094 | 25.27 ± 3.29 | 25.27 ± 3.22 | 0.854 |
BSA, m2, mean ± SD | 1.90 ± 0.18 | 1.89 ± 0.18 | 0.271 | 1.90 ± 0.41 | 1.90 ± 0.19 | 0.975 |
EF, % | 62 ± 7 | 61 ± 7 | 0.002 | 61 ± 7 | 61 ± 7 | 0.375 |
EuroSCORE |  |  |  < 0.001 |  |  | 0.795 |
Low risk (0–2) | 1366 (71.1) | 7810 (62.4) |  | 1336 (71.1) | 1348 (71.7) |  |
Medium risk (3–5) | 486 (25.3) | 4135 (33.0) |  | 476 (25.3) | 471 (25.1) |  |
High risk (≥ 6) | 69 (3.6) | 577 (4.6) |  | 68 (3.6) | 61 (3.2) |  |
Comorbidities, n (%) | ||||||
 Smoking | 792 (41.2) | 5342 (42.7) | 0.237 | 779 (41.4) | 819 (43.6) | 0.187 |
 Diabetes mellitus | 399 (20.8) | 2568 (20.5) | 0.791 | 390 (20.7) | 395 (21.0) | 0.841 |
 Hypertension | 854 (44.5) | 5760 (46.0) | 0.206 | 836 (44.5) | 888 (47.2) | 0.089 |
 Hyperlipidemia | 733 (38.2) | 4775 (38.1) | 0.984 | 714 (38.0) | 744 (39.6) | 0.315 |
 Cerebrovascular accidents | 76 (4.0) | 588 (4.7) | 0.150 | 75 (4.0) | 67 (3.6) | 0.494 |
 History of cardiac surgery | 58 (3.0) | 319 (2.5) | 0.277 | 58 (3.1) | 63 (3.4) | 0.644 |
Laboratory tests prior to cardiac surgery | ||||||
 Hemoglobin, g/L | 136 (128, 146) | 136 (127, 145) | 0.443 | 136 (128, 146) | 136 (129, 145) | 0.837 |
 HCT, % | 0.430 (0.400, 0.492) | 0.430 (0.395, 0.509) | 0.999 | 0.430 (0.400, 0.491) | 0.430 (0.396, 0.497) | 0.759 |
 Platelet counts, *109/L | 197 (173, 230) | 197 (168, 227) | 0.027 | 197 (173, 227) | 197 (171, 226) | 0.288 |
 Albumin, g/L | 40.4 (38.3, 42.2) | 40.4 (38.6, 42.5) | 0.082 | 40.4 (38.3, 42.3) | 40.4 (38.3, 42.5) | 0.816 |
 ALT, IU/L | 19 (14, 27) | 19 (14, 27) | 0.553 | 19 (14, 27) | 19 (14, 26) | 0.150 |
 AST, IU/L | 22 (18, 26) | 22 (18, 26) | 0.702 | 22 (18, 26) | 22 (18, 26) | 0.913 |
 Creatinine, μmol/L | 84.90 (74.39, 95.86) | 84.00 (74.13, 95.94) | 0.475 | 84.92 (74.40, 95.74) | 84.29 (74.76, 95.65) | 0.563 |
 Blood urea nitrogen, mmol/L | 6.18 (5.13, 7.55) | 6.09 (5.01, 7.60) | 0.139 | 6.18 (5.13, 7.55) | 6.13 (5.11, 7.58) | 0.456 |
Preoperative medication | ||||||
 Diuretics | 282 (14.7) | 1996 (15.9) | 0.158 | 275 (14.6) | 283 (15.1) | 0.714 |
 Vasoactive agents | 179 (9.3) | 1203 (9.6) | 0.688 | 174 (9.3) | 183 (9.7) | 0.617 |
 β-receptor blocker | 1091 (56.8) | 7292 (58.2) | 0.234 | 1067 (56.8) | 1117 (59.4) | 0.098 |
 ACEI/ARB | 296 (15.6) | 1968 (15.7) | 0.730 | 289 (15.4) | 294 (15.6) | 0.822 |
 CCB | 80 (4.2) | 628 (5.0) | 0.108 | 79 (4.2) | 96 (5.1) | 0.188 |
Years of performing surgery |  |  < 0.001 |  |  | 0.997 | |
 2018 | 239 (12.4) | 3407 (27.2) |  | 236 (12.6) | 242 (12.9) |  |
 2019 | 383 (19.9) | 3087 (24.7) |  | 375 (19.9) | 370 (19.7) |  |
 2020 | 327 (17.0) | 1884 (15.0) |  | 325 (17.3) | 321 (17.1) |  |
 2021 | 634 (33.0) | 2876 (23.0) |  | 614 (32.7) | 618 (32.9) |  |
 2022 | 338 (17.6) | 1268 (10.1) |  | 330 (17.6) | 329 (17.5) |  |
 Types of surgery |  |  | 0.552 |  |  | 0.270 |
 CABG | 748 (38.9) | 4875 (38.9) |  | 730 (38.8) | 762 (40.5) |  |
 Valve | 779 (40.6) | 5139 (41.0) |  | 762 (40.5) | 706 (37.6) |  |
 CABG combined with valve | 139 (7.2) | 973 (7.8) |  | 136 (7.2) | 153 (8.1) |  |
 Major aortic surgery | 255 (13.3) | 1535 (12.3) |  | 252 (13.4) | 259 (13.8) |  |
Perfusion characteristics | ||||||
 CPB time, min | 114 (92, 144) | 109 (87, 139) |  < 0.001 | 114 (92, 144) | 113 (92, 145) | 0.784 |
 ACC time, min | 83 (65, 108) | 79 (61, 104) |  < 0.001 | 83 (65, 108) | 83 (65, 109) | 0.896 |
 Fluid balance, mL | 570 (10, 1200) | 500 (− 50, 1100) |  < 0.001 | 570 (0, 1200) | 500 (0, 1100) | 0.076 |
 Type of cardioplegia |  |  |  < 0.001 |  |  | 0.708 |
 Blood cardioplegia | 1239 (65.5) | 9099 (72.7) |  | 1208 (64.3) | 1219 (64.8) |  |
 No cardioplegia | 682 (25.5) | 3423 (27.3) |  | 672 (35.7) | 661 (35.2) |  |