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. Author manuscript; available in PMC: 2022 Oct 1.
Published in final edited form as: Surgery. 2021 Jun 17;170(4):1031–1038. doi: 10.1016/j.surg.2021.05.020

Table 1 –

Study Cohort Characteristics: Overall and Trend by Team Familiarity Terciles

Overall Team Familiarity Terciles
Variable Overall Low (1.0–17.0) Medium (17.2–27.2) High (>27.2) p-trend
Frequency 4445 1474 1486 1485
Provider Experience, years
Surgeon 12.18 [5.83, 21.92] 6.70 [1.45, 14.85] 13.82 [10.40, 21.30] 20.94 [9.16, 24.28] <.0001
Anesthesiologist 4.37 [2.16, 10.55] 4.10 [2.01, 10.63] 4.38 [2.20, 10.31] 4.65 [2.30, 10.62] 0.0829
Perfusionist 4.22 [1.31, 16.78] 3.72 [0.90, 20.50] 4.42 [1.39, 17.50] 4.34 [1.66, 10.45] 0.0249
Physician Assistant 20.55 [5.25, 26.66] 19.08 [4.29, 25.66] 20.11 [4.73, 26.79] 24.21 [12.85, 27.09] <.0001
Surgical resident experience (if present) 5.61 [2.82,6.88] 5.37 [2.70,6.65] 5.62 [2.80,6.99] 5.73 [2.98,6.91] 0.0185
Surgical Resident Present, % yes 2507 (56.4) 757 (51.4) 900 (600.6) 850 (57.2) <.0001
Surgeon volume 2 yr prior to the surgery (Median [IQR]) 355.00 [324.00, 435.00] 326.00 [177.00, 368.50] 387.00 [339.00, 447.75] 370.00 [337.00, 436.00] <.0001
EuroSCORE-II (Median [IQR]) (%) 3.91 [1.65,9.54] 4.63 [1.99, 10.33] 3.61 [1.52,9.40] 3.58 [1.51,9.22] <.0001
<.0001
low (<2.2%) 1485 (33.4) 415 (28.2) 522 (35.1) 548 (36.9)
medium (2.2–6.9%) 1478 (33.3) 519 (35.2) 489 (32.9) 470 (31.6)
high (>6.9 %) 1482 (33.3) 540 (36.6) 475 (32.0) 467 (31.4)
Demographics
Age (median [IQR]) 63.00 [54.00, 71.00] 64.00 [55.00, 71.00] 64.00 [54.00, 71.00] 63.00 [52.00, 71.00] 0.0192
Male, % yes 2921 (65.7) 1039 (70.5) 938 (63.1) 944 (63.6) <.0001
Body Surface Area, m2
Median [IQR] 2.04 [1.86, 2.22] 2.06 [1.89, 2.25] 2.03 [1.85, 2.21] 2.02 [1.84, 2.21] 0.0001
0.0194
<1.6 223 (5.0) 61 (4.1) 86 (5.8) 76 (5.1)
1.6–1.8 636 (14.3) 191 (13.0) 218 (14.7) 227 (15.3)
1.8–2.0 1091 (24.5) 343 (23.3) 359 (24.2) 389 (26.2)
>=2.0 2495 (56.1) 879 (59.6) 823 (55.4) 793 (53.4)
Risk Factors
Diabetes on insulin, % yes 399 (9.0) 146 (9.9) 127 (8.5) 126 (8.5) 0.1771
Poor Mobility, % yes <.0001
None 1916 (43.1) 722 (49.0) 614 (41.3) 580 (39.1)
<6 sec 1733 (39.0) 527 (35.8) 599 (40.3) 607 (40.9)
>=6 sec 796 (17.9) 225 (15.3) 273 (18.4) 298 (20.1)
Cardiovascular Disease
Renal Impairment, % yes 0.7434
Normal 2326 (52.3) 789 (53.5) 770 (51.8) 767 (51.6)
Moderately Impaired Renal Function (50–85 ml/min) 1602 (36.0) 519 (35.2) 546 (36.7) 537 (36.2)
Severely Impaired Renal Function (<50 ml/min) off Dialysis 412 (9.3) 138 (9.4) 132 (8.9) 142 (9.6)
On Dialysis 105 (2.4) 28 (1.9) 38 (2.6) 39 (2.6)
Chronic Lung Disease (moderate and severe), % yes 287 (6.5) 111 (7.5) 94 (6.3) 82 (5.5) 0.0263
Extracardiac Arteriopathy, % yes <.0001
None 3208 (72.2) 1004 (68.1) 1062 (71.5) 1142 (76.9)
Peripheral Arterial Disease 615 (13.8) 262 (17.8) 188 (12.7) 165 (11.1)
Carotid Occlusion or >50% Stenosis 622 (14.0) 208 (14.1) 236 (15.9) 178 (12.0)
Active Endocarditis, % yes 182 (4.1) 67 (4.5) 50 (3.4) 65 (4.4) 0.8202
Canadian Cardiovascular Society Class 4 angina, % yes 700 (15.7) 312 (21.2) 203 (13.7) 185 (12.5) <.0001
NY Heart Association Class, % yes 0.0026
None 2573 (57.9) 920 (62.4) 813 (54.7) 840 (56.6)
Class I 150 (3.4) 48 (3.3) 52 (3.5) 50 (3.4)
Class II 779 (17.5) 217 (14.7) 279 (18.8) 283 (19.1)
Class III 613 (13.8) 194 (13.2) 215 (14.5) 204 (13.7)
Class IV 330 (7.4) 95 (6.4) 127 (8.5) 108 (7.3)
Left Ventricular Ejection Fraction, % yes 0.3466
>50% 3434 (77.3) 1137 (77.1) 1133 (76.2) 1164 (78.4)
31–50% 644 (14.5) 229 (15.5) 218 (14.7) 197 (13.3)
21–30% 157 (3.5) 50 (3.4) 57 (3.8) 50 (3.4)
<20% 210 (4.7) 58 (3.9) 78 (5.2) 74 (5.0)
Recent Myocardial Infarction (within 21d), % yes 1589 (35.7) 571 (38.7) 527 (35.5) 491 (33.1) 0.0013
Pulmonary Hypertension, % yes <.0001
Normal or 2244 (50.5) 766 (52.0) 718 (48.3) 760 (51.2)
Unknown
Moderate (Systolic 31–55mmHg) 1662 (37.4) 577 (39.1) 567 (38.2) 518 (34.9)
Severe (Systolic >55mmHg) 539 (12.1) 131 (8.9) 201 (13.5) 207 (13.9)
Acuity, % yes <.0001
Elective 3247 (73.0) 973 (66.0) 1109 (74.6) 1165 (78.5)
Emergent 222 (5.0) 133 (9.0) 58 (3.9) 31 (2.1)
Urgent 976 (22.0) 368 (25.0) 319 (21.5) 289 (19.5)
Previous Cardiac Surgery, % yes 1913 (43.0) 617 (41.9) 612 (41.2) 684 (46.1) 0.0208
Procedure
Surgery Type, % yes <.0001
Isolated 669 (15.1) 304 (20.6) 221 (14.9) 144 (9.7)
Single, Non Coronary Artery Bypass Grafting 2460 (55.3) 799 (54.2) 781 (52.6) 880 (59.3)
2–3 procedures 882 (19.8) 235 (15.9) 324 (21.8) 323 (21.8)
Other 434 (9.8) 136 (9.2) 160 (10.8) 138 (9.3)
Surgery on Thoracic Aorta, % yes 1147 (25.8) 572 (38.8) 299 (20.1) 276 (18.6) <.0001
Day of the Week (%)
Sunday 101 (2.3) 50 (3.4) 35 (2.4) 16 (1.1)
Monday 853 (19.2) 314 (21.3) 292 (19.7) 247 (16.6)
Tuesday 941 (21.2) 276 (18.7) 264 (17.8) 401 (27.0)
Wednesday 806 (18.1) 342 (23.2) 314 (21.1) 150 (10.1)
Thursday 833 (18.7) 216 (14.7) 262 (17.6) 355 (23.9)
Friday 791 (17.8) 223 (15.1) 276 (18.6) 292 (19.7)
Saturday 120 (2.7) 53 (3.6) 43 (2.9) 24 (1.6)
Procedure Start Time (%) <.0001
Afternoon 924 (20.8) 315 (21.4) 352 (23.7) 257 (17.3)
Evening 103 (2.3) 50 (3.4) 38 (2.6) 15 (1.0)
Morning 3324 (74.8) 1048 (71.1) 1071 (72.1) 1205 (81.1)
Overnight 94 (2.1) 61 (4.1) 25 (1.7) 8 (0.5)
Year (%) <.0001
2016 521 (11.7) 143 (9.7) 171 (11.5) 207 (13.9)
2017 1016 (22.9) 295 (20.0) 354 (23.8) 367 (24.7)
2018 1189 (26.7) 479 (32.5) 342 (23.0) 368 (24.8)
2019 1214 (27.3) 404 (27.4) 457 (30.8) 353 (23.8)
2020 505 (11.4) 153 (10.4) 162 (10.9) 190 (12.8)

Poor Mobility - Measured using the average of three 5-meter walk tests

Chronic Lung Disease - long term use of bronchodilators or steroids for lung disease

Active Endocarditis - patient still on antibiotic treatment for endocarditis at time of surgery

*

To test the trend of these variables across the ordered team familiarity terciles, the Cochran-Armitage trend tests were used for the binary variables, Cochran-Mantel_Haenszel tests were used for the categorical variables with more than two levels, Jonckheere-Terpstra trend tests were used for the continuous variables.