Table 1.
Patient characteristics among those who developed one or more STS-defined FTR complications, by center-level case volume quartile.
| Characteristic | Low Volume (n = 468, 8.81%, n centers = 5) |
Medium Volume (n = 857, 16.1%, n centers = 4) |
High Volume (n = 1269, 23.9%, n centers = 4) |
Very High Volume (n = 2721, 51.2%, n centers = 4) |
p-value |
|---|---|---|---|---|---|
| Age | 69 (61 – 75) | 68 (60 – 75) | 67 (60 – 73) | 67 (60 -74) | 0.050 |
| Female Sex | 161 (34.4) | 299 (34.9) | 480 (37.8) | 942 (34.6) | 0.232 |
| White Race | 370 (79.1) | 697 (81.3) | 841 (66.3) | 2045 (75.2) | <0.001 |
| ESRD | 19 (4.06) | 35 (4.08) | 105 (8.27) | 138 (5.07) | <0.001 |
| Pre-operative creatinine level | 1.02 (0.815 - 1.34) | 1.03 (0.83 – 1.32) | 1.10 (0.90 – 1.50) | 1.00 (0.80 – 1.40) | < 0.001 |
| Pre-operative Hemoglobin level | 12.6 (11.1 – 14.0) | 12.7 (11.1 – 14.0) | 12.3 (10.7 – 13.7) | 12.6 (11.0 – 13.9) | < 0.001 |
| Pre-operative white blood cell count | 8.00 (6.50 – 9.90) | 7.92 (6.40 – 10.0) | 8.10 (6.40 – 10.2) | 8.00 (6.50 – 10.0) | 0.741 |
| Pre-operative total albumin | 3.60 (3.20 – 3.80) | 3.60 (3.10 – 3.80) | 3.50 (3.10 – 3.80) | 3.80 (3.40 – 4.10) | <0.001 |
| Chronic Lung Disease | 173 (37.0) | 298 (34.8) | 556 (43.8) | 987 (36.3) | <0.001 |
| MELD | 7.47 (6.40 - 10.0) | 7.57 (7.31 - 10.3) | 8.64 (7.47 – 12.2) | 8.15 (7.31 – 11.0) | <0.001 |
| Liver Disease | 30 (6.41) | 37 (4.32) | 78 (6.15) | 177 (6.50) | 0.306 |
| Oxygen-dependent lung disease | 7 (1.50) | 5 (0.58) | 16 (1.26) | 15 (0.55) | 0.032 |
| Obstructive sleep apnea | 73 (15.6) | 133 (15.5) | 261 (20.6) | 491 (18.0) | 0.011 |
| Current Tobacco Use | 118 (25.2) | 211 (24.6) | 304 (24.0) | 504 (18.5) | <0.001 |
| Cerebrovascular Disease | 150 (32.1) | 238 (27.8) | 340 (26.8) | 661 (24.3) | < 0.001 |
| Prior Stroke | 72 (15.4) | 104 (12.1) | 170 (13.4) | 342 (12.6) | 0.316 |
| Hypertension | 419 (89.5) | 747 (87.2) | 1151 (90.7) | 2325 (85.5) | <0.001 |
| Peripheral Arterial Disease | 90 (19.2) | 155 (18.1) | 239 (18.8) | 458 (16.8) | 0.339 |
| Diabetes Mellitus | 240 (51.3) | 391 (45.6) | 660 (52.0) | 1273 (46.8) | 0.004 |
| Immunocompromise | 30 (6.41) | 38 (4.43) | 79 (6.23) | 125 (4.59) | 0.066 |
| Pre-operative Arrhythmia | 61 (13.0) | 121 (14.1) | 215 (16.9) | 427 (15.7) | 0.037 |
| CHF | 229 (48.9) | 274 (32.0) | 710 (56.0) | 1333 (49.0) | <0.001 |
| Prior MI | 295 (63.0) | 453 (52.9) | 688 (54.2) | 1390 (51.1) | <0.001 |
| Body Surface Area | 2.87 (2.71 – 2.98) | 2.87 (2.72 – 3.00) | 2.83 (2.71 – 2.97) | 2.87 (2.72 – 2.97) | 0.126 |
| Ejection Fraction | 55.0 (40.0 – 60.0) | 55.0 (43.0 - 60.0) | 50.0 (35.0 – 60.0) | 55.0 (40.0 – 60.0) | <0.001 |
| Prior PCI | 133 (28.4) | 238 (27.8) | 340 (26.8) | 676 (24.8) | 0.166 |
| Prior CABG | 13 (2.78) | 24 (2.80) | 46 (3.62) | 140 (5.15) | 0.003 |
| Prior Valve | 8 (1.71) | 21 (2.45) | 60 (4.73) | 158 (5.81) | <0.001 |
| Health Insurance | 441 (94.2) | 802 (93.6) | 1064 (83.9) | 2562 (94.2) | < 0.001 |
| First Cardiac Surgery | 453 (96.8) | 821 (95.8) | 1181 (93.1) | 2447 (89.9) | <0.001 |
| Status | <0.001 | ||||
| Elective | 139 (29.7) | 308 (35.9) | 407 (32.1) | 1048 (38.5) | |
| Urgent | 271 (57.9) | 486 (56.7) | 761 (60.0) | 1382 (50.8) | |
| Emergent | 57 (12.2) | 55 (6.42) | 87 (6.86) | 264 (9.70) | |
| Emergent Salvage | 1 (0.21) | 8 (0.93) | 14 (1.10) | 27 (0.99) | |
| Pre-operative Intraaortic balloon pump | 132 (28.2) | 204 (23.8) | 325 (25.6) | 644 (23.7) | 0.136 |
| Procedure Type | <0.001 | ||||
| Isolated CABG | 333 (71.2) | 566 (66.0) | 788 (62.1) | 1547 (56.9) | |
| Isolated AVR | 34 (7.26) | 74 (8.63) | 114 (8.98) | 295 (10.8) | |
| AVR + CABG | 39 (8.33) | 98 (11.4) | 115 (9.06) | 269 (9.89) | |
| MV Repair | 15 (3.21) | 21 (2.45) | 47 (3.70) | 140 (5.15) | |
| MV Repair + CABG | 17 (3.63) | 25 (2.92) | 64 (5.04) | 120 (4.41) | |
| MV Replacement + CABG | 16 (3.42) | 36 (4.20) | 44 (3.47) | 84 (3.09) | |
| MV Replacement | 14 (2.99) | 37 (4.32) | 97 (7.64) | 266 (9.78) | |
| Aortic Stenosis | 82 (17.5) | 188 (21.9) | 239 (18.8) | 543 (20.0) | 0.188 |
| Severe Aortic Regurgitation | 11 (2.35) | 28 (3.27) | 32 (2.68) | 94 (3.45) | 0.035 |
| Mitral Stenosis | 11 (2.35) | 29 (3.38) | 53 (4.18) | 150 (5.51) | 0.003 |
| Severe Mitral Regurgitation | 54 (11.5) | 92 (10.7) | 187 (14.7) | 439 (16.1) | <0.001 |
| Tricuspid Stenosis | 2 (0.43) | 2 (0.23) | 0 (0.00) | 9 (0.33) | 0.205 |
| Severe Tricuspid Regurgitation | 6 (1.28) | 10 (1.17) | 34 (2.68) | 73 (2.68) | <0.001 |
| Cross clamp time | 75.0 (57.0 - 103) | 86.0 (67.0 - 116) | 83.0 (71.0 – 115) | 78.0 (61.0 – 104) | <0.001 |
| Cardiopulmonary bypass time | 103 (80.5 – 153) | 120 (95.0 - 159) | 120 (92.0 - 165) | 112 (86.0 – 151) | < 0.001 |
| Intraoperative blood product | 0 (0-2) | 0 (0-2) | 0 (0-2) | 0 (0-2) | <0.001 |
| STS Predicted Risk of Mortality | 2.45 (1.13 – 5.98) | 2.44 (1.22-5.08) | 3.19 (1.45 – 7.43) | 2.81 (1.31 – 5.91) | <0.001 |
Q1: Centers with annual median case volume ranging from 79-136 cases, Q2: >136 - 226 cases, Q3: >226-284 cases, Q4: >284 -682 cases.