Table 1.
Patient Demographics, Medications, and Perioperative Clinical Risk Factors for Increased Hospital Length of Stay and Mortality after Primary Coronary Artery Bypass Grafting
| Preoperative Demographics and Risk Factors (n = 1,183) | Mean or Proportion | Univariate Association with HLOS (Hazard Ratio, P Value) | Univariate Association with All-cause Mortality (Hazard Ratio, P Value) 115 Death Events |
|---|---|---|---|
| Age (yr) | 63.8 ± 10.1 | 1.01, < 0.0001 | 1.08, < 0.0001 |
| Female gender | 213 (18.0) | 1.10, 0.20 | 0.93, 0.76 |
| Institution | |||
| Brigham and Women’s Hospital | 879 (74.3) | 1.31, < 0.0001 | 0.75, 0.21 |
| Texas Heart Institute | 304 (25.7) | ||
| Ethnicity (minority) | 190 (16.1) | 1.13, 0.12 | 0.51, 0.04 |
| Diabetes mellitus (n = 1,182) | 344 (29.1) | 1.14, 0.04 | 1.32, 0.16 |
| Hypertension (n = 1,180) | 882 (74.7) | 1.21, 0.004 | 1.00, 0.99 |
| Hypercholesterolemia (n = 1,178) | 886 (75.2) | 0.85, 0.02 | 0.49, 0.0002 |
| Obesity (BMI > 30 kg/m2) | 471 (39.8) | 1.18, 0.006 | 1.23, 0.28 |
| Smoking, > 30-pack-year history (n = 1,135) | 305 (26.9) | 1.16, 0.03 | 2.36, < 0.0001 |
| Preoperative creatinine clearance (ml · min−1 · 1.73 m−2) (n = 1,182) | 74.7 ± 20.7 | 0.995, < 0.0001 | 0.99, 0.02 |
| Myocardial infarction ≤ 2 wk preoperatively (n = 1,181) | 206 (17.4) | 1.28, 0.002 | 1.38, 0.15 |
| Left ventricular ejection fraction (%)(n = 1,130) | 52.7 ± 12.4 | 0.99, < 0.0001 | 0.97, < 0.0001 |
| Coronary artery regions with > 50% stenosis | Overall P value 0.01 | Overall P value 0.03 | |
| 0–1 Region | 87 (7.3) | 1 | 1 |
| 2 Regions | 390 (33.0) | 0.74 | 0.43 |
| 3 Regions | 706 (59.7) | 0.85 | 0.47 |
| Mitral insufficiency (moderate or severe) (n = 1,142) | 25 (2.2) | 1.30, 0.20 | 3.34, 0.002 |
| Past arrhythmia | 118 (10.0) | 1.57, < 0.0001 | 2.23, 0.0009 |
| Anemia (n = 1,180) | 391 (33.1) | 1.27, 0.0001 | 1.94, 0.0004 |
| Median preoperative BNP (pg/ml) (10th and 90th percentile), mean preoperative BNP (pg/ml) ± SD | 16.4, [1.5, 122.8], 47.6 ± 92.8 | 1.22 for log10 increase, < 0.0001 | 1.99 for log10 increase, < 0.0001 |
| Preoperative cTnI > 0.1μg/l | 173 (14.6) | 1.11, 0.21 | 0.91, 0.72 |
| Preoperative medications | |||
| ACE inhibitor (n = 1,182) | 549 (46.4) | 1.10, 0.09 | 0.84, 0.34 |
| Diuretic (n = 1,182) | 249 (21.1) | 1.42, < 0.0001 | 1.33, 0.18 |
| Statin | 915 (77.3) | 0.87, 0.04 | 0.55, 0.002 |
| Digoxin | 32 (2.7) | 1.81, 0.002 | 3.94, < 0.0001 |
| β blocker | 913 (77.2) | 0.87, 0.05 | 0.67, 0.04 |
| Aspirin | 899 (76.0) | 0.89, 0.10 | 0.73, 0.12 |
| Nonaspirin platelet inhibitor (n = 1,182) | 257 (21.7) | 1.29, 0.0003 | 0.83, 0.45 |
| Nitroglycerin intravenous (n = 1,178) | 120 (10.2) | 1.04, 0.67 | 0.87, 0.67 |
| Heparin intravenous | 267 (22.6) | 1.10, 0.16 | 1.13, 0.58 |
| Surgical risk factors | |||
| Urgent surgery (n = 1,181) | 647 (54.8) | 1.02, 0.71 | 1.20, 0.33 |
| Cardiopulmonary bypass time > 120 min | 257 (21.7) | 1.20, 0.01 | 0.58, 0.04 |
| No. coronary grafts (n = 1,182) | Overall P value 0.65 | Overall P value 0.003 | |
| 1–2 Grafts | 176 (14.9) | 1 | 1 |
| 3 Grafts | 533 (45.1) | 0.97 | 1.05 |
| ≥ 4 Grafts | 473 (40.0) | 1.03 | 0.51 |
| In-hospital postoperative outcomes | |||
| Ventricular dysfunction | 138 (11.7) | 2.33, < 0.0001 | 2.75, < 0.0001 |
| New onset atrial fibrillation | 340 (28.7) | 1.81, < 0.0001 | 2.14, < 0.0001 |
| Postoperative creatinine clearance (ml · min−1 · 1.73 m−2) (n = 1,182) | 68.3 ± 21.5 | 0.99, < 0.0001 | 0.98, < 0.0001 |
| Peak postoperative cTnI (μg/l) | 1.25 [0.37, 7.49] | 1.32 for log10 increase, < 0.0001 | 0.90 for log10 increase, 0.56 |
Data are shown as n (%) for dichotomous variables and mean ± SD or median (10th and 90th percentiles) for continuous variables. ACE = angiotensin converting enzyme; BMI = body mass index; BNP = B-type natriuretic peptide; HLOS = hospital length of stay.