Table 1.
Baseline characteristics of the final study population, hospital survivors, and inpatient deaths
| Variables | Final study population (n = 11 266) | Inpatient deaths (n = 979) | Hospital survivors (n = 10 287) | P-value |
|---|---|---|---|---|
| Demographics | ||||
| Age (years) | 67.6 ± 15.0 | 71.6 ± 13.7 | 67.2 ± 15.1 | <0.001 |
| Female, n (%) | 4202 (37.3%) | 393 (40.1%) | 3809 (37.0%) | 0.05 |
| Caucasian, n (%) | 10 410 (92.6%) | 881 (90.0%) | 9529 (92.6%) | 0.003 |
| CICU length of stay (days) | 2.6 ± 4.4 | 3.4 ± 4.3 | 2.5 ± 4.5 | <0.001 |
| Hospital length of stay (days) | 8.2 ± 13.8 | 9.6 ± 19.7 | 8.1 ± 13.1 | <0.001 |
| CICU mortality | 589 (5.2%) | 589 (60.2%) | 0 (0%) | NA |
| Hospital mortality | 979 (8.7%) | 979 (100%) | 0 (0%) | NA |
| One-year mortality | 2459 (21.8%) | 979 (100%) | 1480 (14.4%) | NA |
| Comorbidities | ||||
| Charlson comorbidity index | 2.3 ± 2.6 | 3.1 ± 2.9 | 2.3 ± 2.6 | <0.001 |
| Prior myocardial infarction | 2085 (18.5%) | 194 (19.8%) | 1891 (18.4%) | 0.28 |
| Prior heart failure | 2146 (19.1%) | 259 (26.5%) | 1887 (18.4%) | <0.001 |
| Prior stroke | 1324 (11.8%) | 167 (17.1%) | 1157 (11.3%) | <0.001 |
| Prior diabetes mellitus | 3199 (28.4%) | 328 (33.5%) | 2871 (28.0%) | <0.001 |
| Prior lung disease | 2129 (18.9%) | 244 (24.9%) | 1885 (18.4%) | <0.001 |
| Prior chronic kidney disease | 2248 (20.0%) | 279 (28.5%) | 1969 (19.2%) | <0.001 |
| Prior dialysis | 564 (5.0%) | 103 (10.5%) | 461 (4.5%) | <0.001 |
| Admission diagnosesa | ||||
| Acute coronary syndrome | 5056 (45.2%) | 420 (42.9%) | 4636 (45.5%) | 0.13 |
| Heart failure | 5398 (48.3%) | 643 (65.8%) | 4755 (46.6%) | <0.001 |
| Shock | 1724 (15.4%) | 525 (53.7%) | 1199 (11.8%) | <0.001 |
| Cardiogenic shock | 1395 (12.5%) | 424 (43.4%) | 971 (9.5%) | <0.001 |
| Cardiac arrest | 1357 (12.2%) | 432 (44.2%) | 925 (9.1%) | <0.001 |
| Ventricular fibrillation arrest | 710 (6.4%) | 173 (17.7%) | 537 (5.3%) | <0.001 |
| Respiratory failure | 2723 (24.4%) | 631 (64.5%) | 2092 (20.5%) | <0.001 |
| Sepsis | 730 (6.5%) | 218 (22.3%) | 512 (5.0%) | <0.001 |
| Severity of illness scores | ||||
| Day 1 SOFA score | 3.5 ± 3.2 | 7.7 ± 4.2 | 3.1 ± 2.8 | <0.001 |
| APACHE-III score | 61.0 ± 25.1 | 93.0 ± 33.4 | 57.9 ± 21.8 | <0.001 |
| APACHE-IV predicted death (%) | 17.0 ± 19.9 | 44.1 ± 28.9 | 14.4 ± 16.6 | <0.001 |
| Admission Braden Skin Score | 17.7 ± 3.4 | 14.1 ± 3.6 | 18.0 ± 3.2 | <0.001 |
| Procedures and therapies | ||||
| Inpatient coronary angiogram | 6807 (60.4%) | 443 (45.2%) | 6364 (61.9%) | <0.001 |
| Inpatient PCI | 4148 (36.8%) | 228 (23.3%) | 3920 (38.1%) | <0.001 |
| IABP in CICU | 1024 (9.1%) | 163 (16.6%) | 861 (8.4%) | <0.001 |
| Pulmonary artery catheter | 1047 (9.3%) | 162 (16.6%) | 885 (8.6%) | <0.001 |
| Red blood cell transfusion | 1306 (11.6%) | 228 (23.3%) | 1078 (10.5%) | <0.001 |
| Dialysis in CICU | 545 (4.8%) | 175 (17.9%) | 370 (3.6%) | <0.001 |
| CRRT | 229 (2.0%) | 109 (11.1%) | 120 (1.2%) | <0.001 |
| Non-invasive ventilator | 1747 (15.5%) | 232 (23.7%) | 1515 (14.7%) | <0.001 |
| Invasive ventilator | 1913 (17.0%) | 538 (55.0%) | 1375 (13.4%) | <0.001 |
|
Vasoactive drugs # vasoactive drugs |
2830 (25.1%) 0.5 ± 1.0 |
640 (65.4%) 1.5 ± 1.5 |
2190 (21.3%) 0.4 ± 0.8 |
<0.001 <0.001 |
| In-hospital cardiac arrest | 284 (2.5%) | 127 (13.0%) | 157 (1.5%) | <0.001 |
| Echocardiographic and AI-ECG findings | ||||
| Inpatient TTE | 9582 (87.2%) | 779 (85.6%) | 8803 (87.3%) | 0.14 |
| TTE within 1 day of CICU admission | 6963 (61.8%) | 574 (58.6%) | 6389 (62.1%) | 0.03 |
| LVEF (%)a | 47.3 ± 16.5 | 40.5 ± 18.5 | 47.9 ± 16.1 | <0.001 |
| Normal LVEF for sexa | 3843 (46.6%) | 219 (31.3%) | 3624 (48.0%) | <0.001 |
| Mild LVSDa | 1514 (18.4%) | 101 (14.4%) | 1413 (18.7%) | |
| Moderate LVSDa | 1470 (17.8%) | 137 (19.6%) | 1333 (17.7%) | |
| Severe LVSDa | 1415 (17.2%) | 242 (24.6%) | 1173 (15.6%) | |
| LVEF ≤35% by TTEa | 2277 (27.6%) | 326 (46.6%) | 1951 (25.9%) | <0.001 |
| AI-ECG probability of LVSD | 0.352 ± 0.373 | 0.490 ± 0.378 | 0.339 ± 0.370 | <0.001 |
| Predicted LVEF ≤35% | 4257 (37.8%) | 529 (54.0%) | 3728 (36.2%) | <0.001 |
| True negativea | 4540 (55.1%) | 240 (34.3%) | 4300 (57.0%) | <0.001 |
| False positivea | 1425 (17.3%) | 133 (19.0%) | 1292 (17.1%) | |
| False negativea | 567 (6.9%) | 67 (9.6%) | 500 (6.6%) | |
| True positivea | 1710 (20.8%) | 259 (37.0%) | 1451 (19.2%) |
Data displayed as n (%) for categorical variables or mean ± standard deviation for continuous variables. Reported P-value is for between-groups comparison using Pearson χ2 test (categorical variables) or Wilcoxon rank-sum test (continuous variables) comparing hospital survivors and inpatient deaths.
ACS, acute coronary syndrome; AI-ECG, artificial intelligence-enhanced electrocardiogram; APACHE, Acute Physiology and Chronic Health Evaluation; CICU, cardiac intensive care unit; CRRT, continuous renal replacement therapy; ECG, electrocardiogram; IABP, intra-aortic balloon pump; LVEF, left ventricular ejection fraction; LVSD, left ventricular systolic dysfunction; PCI, percutaneous coronary intervention; SOFA, Sequential Organ Failure Assessment; TTE, transthoracic echocardiogram.
Admission diagnoses were not mutually-exclusive and may sum to greater than 100%.