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. 2022 Nov 9;39(Suppl 5):S6–S11c. doi: 10.12788/fp.0300

Outcomes After Prolonged ICU Stays in Postoperative Cardiac Surgery Patients

Thomas F Curran a,b,✉, Bipin Sunkara c, Aleda Leis a, Adrian Lim d, Jonathan Haft a,b, Milo Engoren a
PMCID: PMC10010497  PMID: 36923547

Abstract

Background

Prolonged postoperative intensive care unit (ICU) stays are common after cardiac surgery and are associated with poor outcomes. There are few studies evaluating how risk factors associated with mortality may change during prolonged ICU stays or how mortality may vary with length of stay. We evaluated operative and long-term mortality in post-cardiac surgery patients after prolonged ICU stays at 7, 14, 21, and 28 days and factors associated with mortality.

Methods

We included University of Michigan Medical Center cardiac surgery patients with ≥ 7 postoperative days in the ICU. We determined factors associated with hospital mortality at 7, 14, 21, and 28 days of ICU stay using logistic regression, and among hospital survivors, we determined the factors associated with long-term mortality using Cox regression.

Results

Of 8309 ICU admissions from cardiac surgery, 1174 (14%) had ICU stays > 7 days. Operative mortality was 11%, 18%, 22%, and 35% for the 7-, 14-, 21-, and 28-day groups, respectively. Mechanical ventilation on the day of assessment was associated with increased odds ratios of operative mortality in all models. Of the 1049 (89%) hospital survivors, 420 (40%) died by late follow-up. Median (IQR) Cox model survival was 10.7 (0.7) years. Longer ICU stays, postoperative pneumonia, and elevated discharge blood urea nitrogen were associated with increased hazard of dying; whereas higher discharge platelet count and cardiac transplant were protective.

Conclusions

Both operative and late mortality increased as the duration of a ICU stay increased after cardiac surgery.

Prolonged intensive care unit (ICU) stays, variably defined as > 48 h to > 14 days, are a known complication of cardiac surgery.1–8 Prolonged stays are associated with higher resource utilization and higher mortality.2,3,9–12 Although there are several cardiac surgery risk models that can be used preoperatively to identify patients at risk for prolonged ICU stay, factors that influence outcomes for patients who experience prolonged ICU stays are poorly understood.2,13–19 Little information is available to inform discussions between health care practitioners (HCPs) and patients throughout a prolonged ICU stay, especially those ≥ 7 days.

As cardiac surgical complexity, patient age, and preexisting comorbidities have increased over time, so has the need to provide patients and HCPs with data to inform decision making, enhance prognostication, and set realistic expectations at varying time intervals during prolonged ICU stay. The purpose of this study was to evaluate short- and long-term outcomes in cardiac surgery patients after prolonged ICU stays at relevant time intervals (7, 14, 21, and 28 days) and to determine factors that may predict a patient’s outcome after a prolonged ICU stay.

METHODS

The University of Michigan Health System institutional review board approved this study and waived informed consent. We merged the University of Michigan Medical Center Society of Thoracic Surgeons (STS) database, which is updated periodically with late mortality, with elements of the electronic health record (EHR). Adult patients were included if they had cardiac surgery at the University of Michigan between January 2, 2001, and December 31, 2011. Late mortality was updated through December 1, 2014. Data are presented as frequency (%), mean (SD), and median (IQR) as appropriate. Bivariate comparisons between survivors and nonsurvivors were done with χ2 or Fisher exact test for categorical data, Student t test for continuous normally distributed data, and Wilcoxon rank sum test for continuous not normally distributed data. To determine factors associated with operative mortality (death within 30 days of surgery or hospital discharge, whichever occurred later), we used logistic regression with forward selection. All available factors were initially entered in the models.

Separate logistic models were created based on all data available at days 7, 14, 21, and 28. Final models consisted of factors with statistically significant P values (< .05) and adjusted odds ratios (AORs) with 95% CIs that excluded 1. To determine factors associated with late mortality, we used a Cox proportional hazard model, which used data available at discharge and STS complications. As these complications did not include their timing, they could only be used in models created at discharge and not for days 7, 14, 21, and 28 models. Final models consisted of factors with P values < .05 and 95% CIs of the AORs or the hazard ratios (HRs) that excluded 1. As the EHR did not start recording data until January 2, 2004, and its capture of data remained incomplete for several years, rather than imputing these missing data or excluding these patients, we chose to create an extra categorical level for each factor to represent missing data. For continuous factors with missing data, we first converted the continuous data to terciles and the missing data became the fourth level.20,21

The discrimination of the logistic models were determined by the c-statistic and for the Cox proportional hazards model with the Harrell concordance index (C index). Time trends were assessed with the Cochran-Armitage trend test. P < .05 was deemed statistically significant. Statistics were calculated with SPSS versions 21–23 or SAS 9.4.

RESULTS

Of 8309 admissions to the ICU after cardiac surgery, 1174 (14%) had ICU stays ≥ 7 days, 386 (5%) ≥ 14 days, 201 (2%) ≥ 21 days, and 80 (0.9%) ≥ 28 days. The prolonged ICU study population was mostly male, White race, with a mean (SD) age of 62 (14) years. Patients had a variety of comorbidities, most notably 61% had hypertension and half had heart failure. Valve surgery (55%) was the most common procedure (n = 651). Twenty-nine percent required > 1 procedure (eAppendix 1, available at doi:10.12788/fp.0300).

The operative mortality for the entire prolonged ICU stay group was 11%, with progressive increases in mortality as ICU stay increased 18%, 22%, and 35% for the ≥ 14, ≥ 21, and ≥ 28 day groups, respectively (Table 1). Univariate analysis demonstrated that survivors were younger and less likely to have comorbidities. Survivors also were less likely to have had valve surgery, require vasopressors, ventilator support, or renal replacement therapy on day 7 (Table 2). At day 14, survivors were more likely to be male, to have ventricular-assist device surgery, and were less likely to have valve surgery (eAppendix 2, available at doi:10.12788/fp.0300). At day 21, survivors were more likely to have presented with cardiogenic shock or heart failure; however, they were also more likely to receive a ventricular-assist device (eAppendix 3, available at doi:10.12788/fp.0300). Similarly, at day 28 operative survivors were more likely to have received a ventricular assist device (eAppendix 4, available at doi:10.12788/fp.0300).

TABLE 1.

Mortality for Patients With Prolonged ICU Stay After Cardiac Surgery

Length of stay, d Patients, No. Operative mortality, No. (%) Total mortality, No. (%)
≥ 7 1174 125 (11) 420 (36)
≥ 14 386 70 (18) 158 (41)
≥ 21 201 44 (22) 96 (48)
≥ 28 80 28 (35) 41 (51)
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Abbreviation: ICU, intensive care unit.

TABLE 2.

Univariate Analysis of Significant Preoperative Factors Associated With Mortality for Patients With Intensive Care Unit Stays ≥ 7 Daysa

Variables At discharge P value At follow-up P value
Survived (n = 1049) Deceased (n = 125) Survived (n = 754) Deceased (n = 420)
Preoperative
 Smoker, No. (%) 261 (35) 211 (50) < .001
 Diabetes mellitus, No. (%) 190 (25) 141 (34) .003
 Renal failure, No. (%) 268 (26) 44 (35) .02
 Dialysis, No. (%) 58 (6) 15 (12) .01
 Hypertension, No. (%) 478 (63) 292 (70) .04
 Infectious endocarditis, No. (%) 88 (9) 19 (15) .02
 Peripheral vascular disease, No. (%) 120 (11) 23 (18) .03 73 (10) 70 (17) .001
 Age, mean (SD), y 61 (14) 64 (12) .02 59 (14) 65 (13) <.001
 Weight, mean (SD), kg, 86 (23) 82 (22) <.001
 Body mass index, mean (SD) 27.8 (7.1) 26.3 (6.7) <.001
 Creatinine, mean (SD), mg/dL 1.46 (1.26) 1.71 (1.58) .04
 Hemoglobin, mean (SD), g/dL 12.0 (2.3) 11.5 (2.2) .004
 Hematocrit, mean (SD), % 35.5 (6.7) 34.1 (6.5) .01
Operative
 Coronary artery bypass grafting, No. (%) 148 (20) 111 (26) .008
 Valve procedure, No. (%) 566 (54) 85 (68) .003
 Ventricular-assist device procedure, No. (%) 200 (19) 13 (10) .02
 Transplant procedure, No. (%) 72 (10) 20 (5) .003
 Perfusion time, mean (SD), min 160 (88) 180 (105) .046
 Intraoperative cryoprecipitate transfusion, median (IQR) 0 (0–0) 0 (0–0) .02
Postoperative day 7
 Vasopressor, No. (%) 99 (16) 27 (33) < .001
 Ventilator support, No. (%) 234 (22) 60 (48) < .001
 Renal replacement therapy, No. (%) 65 (6) 19 (15) .001
 Postoperative pneumonia, No. (%) 118 (18) 117 (29) < .001
 Hematocrit, mean (SD), % 29.9 (4.60 29.8 (4.5) .91 29.5 (4.4) 30.7 (4.8) .001
 Bilirubin, mean (SD), mg/dL 1.7 (2.5) 4.3 (7.3) .01
 Alanine transaminase, mean (SD), U/L 125 (4.3) 248 (423) .03
 White blood cells, mean (SD), 103/μL 12.1 (5.0) 16.5 (9.6) < .001
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a

Data not available for all variables for all patients; for continuous variables with data missing, available data used from total number of patients for survival at discharge, mortality at discharge, survival at follow-up, mortality at follow-up: age, weight, body mass index (1049, 125, 754, 420, respectively); creatinine, hemoglobin, hematocrit (625, 82, 478, 229, respectively); perfusion time (1006, 118, 724, 400, respectively); day 7 creatinine, sodium, chloride, white blood cells (624, 81, 476, 229, respectively); d 7 hemoglobin (622, 80, 474, 228, respectively), d 7 hematocrit (622, 81, 223, 61, respectively), d 7 bilirubin, alanine transaminase, alkaline phosphatase (481, 64, 376, 169, respectively).

Using multivariable logistic regression to adjust for factors associated with mortality, we found that receiving mechanical ventilation on the day of analysis was associated with increased operative mortality with AOR increasing from 3.35 (95% CI, 2.82–3.98) for day 7, to 4.19 (95% CI, 3.25–5.41) for day 14, to 6.06 (95% CI, 4.25–8.62) for day 21, to 15.68 (95% CI, 8.11–30.13) for day 28; all P values < .001 (Figure 1). Use of vasopressors was associated with an increased operative mortality only for the day 7 group, AOR 2.15 (95% CI, 1.17–2.70), P < .001. For days 7, 14, and 28, severe or moderate chronic lung disease was associated with increased AOR of operative mortality: 2.19 (95% CI, 1.52–3.14; P < .001) for day 7,2.73 (95% CI, 1.99–3.75; P < .001) for day 14, and 37.02 (95% CI, 13.57–100.99; P < .001) for day 28 (Table 3). Of the 1049 (89%) hospital survivors, 420 (40%) died by late follow-up (Figure 2). Median (IQR) Cox model survival was 10.7 (0.7) years for all hospital survivors; however, long-term survival varied by ICU length of stay (Figure 3). Longer ICU stays were associated with higher late mortality: 36% for ≥ 7 days, 41% for ≥ 14 days, 48% for 21 days, and 51% for ≥ 28 days (P < .001). Univariate analysis demonstrated that survivors were less likely to have comorbidities or to be ever smokers. Survivors were younger and less likely to have a coronary artery bypass graft and more likely to have transplant surgery compared with patients who died.

FIGURE 1.

FIGURE 1

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Odds Ratio (95% CI) for Operative Mortality for Patients Receiving Mechanical Ventilation on Day of Analysis

TABLE 3.

Multivariate Analyses for Significant Factors Associated With Operative Mortality in Prolonged Intensive Care Unit Staysa

Prolonged ICU Odds ratio (95% CI) P value
Day 7
 Prior stroke 1.41 (1.10–1.80) .006
 Chronic lung disease, mild 0.72 (0.57–0.92) .009
 Chronic lung disease, moderate or severe 2.19 (1.52–3.14) < .001
 Hypothermic circulatory arrest 0.47 (0.36–0.61) < .001
 Vasopressor use 2.15 (1.71–2.70) < .001
 Mechanical ventilation 3.35 (2.82–3.98) < .001
 White blood cell count > 13,100/μL 2.47 (1.92–3.18) < .001
 White blood cell count missing 1.43 (1.11–1.85) .006
Day 14
 Valve surgery 1.45 (1.09–1.92) .01
 Ventricular-assist device surgery 0.36 (0.24–0.56) < .001
 Prior stroke 1.66 (1.20–2.29) .002
 Chronic lung disease, mild 1.23 (1.04–2.24) .03
 Chronic lung disease, moderate or severe 2.73 (1.99–3.75) < .001
 Mechanical ventilation 4.19 (3.25–5.41) < .001
 Hemoglobin ≥ 9.2 g/dL 0.28 (0.14–0.57) < .001
 Alkaline phosphatase 90–138 U/L 3.57 (2.25–5.66) < .001
Day 21
 Mechanical ventilation 6.06 (4.25–8.62) < .001
 Sodium > 139 mEq/L 0.21 (0.13–0.36) < .001
 Bilirubin 0.7–1.2 mg/dL 7.29 (3.86–13.76) < .001
 Bilirubin missing 0.50 (0.26–0.97) .04
Day 28
 Infectious endocarditis 27.85 (9.54–81.33) < .001
 Mechanical ventilation 15.68 (8.11–30.31) < .001
 Sodium 137–139 mEq/L .004 (0.001–0.02) < .001
 Sodium > 139 mEq/L 0.11 (0.04–0.33) < .001
 Sodium missing 0.07 (0.02–0.27) < .001
 Hemoglobin 9–10.1 g/dL 4.00 (1.21–13.21) .02
 Chronic lung disease, mild 2.72 (1.13–6.56) .03
 Chronic lung disease, moderate or severe 37.02 (13.57–100.99) < .001
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Abbreviation: ICU, intensive care unit.

a

Logistic regression showing factors associated with operative mortality in patients with > 7 ICU d mortality was 125 of 1174 (11%), c-statistic (SEM) = 0.722 (0.010); ≥ 14 ICU d mortality was 70 of 386 (18%), c-statistic (SEM) = 0.750 (0.014); ≥ 21 ICU d mortality was 44 of 201 (22%), c-statistic (SEM) = 0.742 (0.020); ≥ 28 ICU d, mortality was 28 of 80 (35%), c-statistic (SEM) = 0.889 (0.017).

FIGURE 2.

FIGURE 2

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Cox Regression for Long-Term Survival in All Patients With Prolonged ICU Surviving to Discharge Abbreviation: ICU, intensive care unit.

FIGURE 3.

FIGURE 3

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Cox Regression for Long-Term Survival in ICU Patients Surviving to Discharge for Prolonged Stays Abbreviation: ICU, intensive care unit.

After multivariable Cox regression to adjust for confounders, we found that each postoperative week was associated with a 7% higher hazard of dying (HR, 1.07; 95% CI, 1.07–1.07; P < .001). Postoperative pneumonia was also associated with increased hazard of dying (HR, 1.59; 95% CI, 1.27–1.99; P < .001), as was elevated blood urea nitrogen. In contrast higher discharge platelet count and cardiac transplant were protective factors (Table 4).

TABLE 4.

Cox Regression Showing Factors Associated With Late Mortality in Patients Who Survived to Hospital Discharge

Factors Odds ratio (95% CI) P value
Transplant surgery 0.32 (0.19–0.54) < .001
Smoke 1.34 (1.09–1.66) .005
Body mass index 1.00 (0.99–1.00) .002
Chronic lung disease
 Mild 1.39 (1.04–1.85) .02
 Moderate 1.59 (1.10–2.29) .01
 Severe 1.64 (1.05–2.58) .03
Postoperative pneumonia 1.59 (1.27–1.99) < .001
Postoperative ICU, length of stay/wk 1.07 (1.07–1.07) < .001
Discharge day levels
 Alanine transaminase > 57 U/L 0.52 (0.35–0.77) .001
 Urea nitrogen > 35 mg/dL 2.15 (1.50–3.07) < .001
 Chloride 101–104 mmol/L 0.63 (0.49–0.89) .01
 Chloride >104 mmol/L 0.66 (0.48–0.92) .01
 Platelet > 321×103/μL 0.41 (0.28–0.59) < .001
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Abbreviation: ICU, Intensive care unit.

a

Mortality: 420 of 1049 (40%); Harrell c-statistic (SEM) = 0.757 (0.030).

DISCUSSION

We found that operative mortality increased the longer the patient stayed in the ICU, ranging from 11% for ≥ 7 days to 35% for ≥ 28 days. We further found that in ICU survivors, median (IQR) survival was 10.7 (0.7) years. While previous studies have evaluated prolonged ICU stays, they have been limited by studying limited subpopulations, such as patients who are dependent on dialysis or octogenarians, or used a single cutoff to define prolonged ICU stays, variably defined from > 48 hours to > 14 days.2–7,9–12,22 Our study is similar to others that used ≥ 2 cutoffs.1,8 However, our study was novel by providing 4 cutoffs to improve temporal prediction of hospital outcomes. Unlike a study by Ryan and colleagues, which found no increase in mortality with longer stay (43.5% for ≥ 14 days and 45% for ≥ 28 days), our study findings are similar to those of Yu and colleagues (11.1% mortality for prolonged ICU stays of 1 to 2 weeks, 26.6% for 2 to 4 weeks, and 31% for > 4 weeks) and others (8%, 3 to 14 days; 40%, >14 days; 10%, 1 to 2 weeks; 25.7% > 2 weeks) in finding a progressively increased hospital mortality with longer ICU stays.1,4,5,8 These differences may be related to different ICU populations or to improvements in care since Ryan and colleagues study was conducted.

Fewer studies have evaluated factors associated with mortality in cardiac surgery prolonged ICU stay patients. Our study is similar to other studies that evaluated risk factors by finding associations between a variety of comorbidities and process of care associated with both operative and long-term mortality; however, comparison between these studies is limited by the varying factors analyzed.1,3,5,6,8,9,11 We found that mechanical ventilation on days 7, 14, 21, and 28 was strongly associated with operative mortality, similar to noncardiac surgery patients and cardiac surgery patients.6,23,24 While we found several processes of care, such as catecholamine use and transfusions to be associated with mortality, which is similar to other studies, notably, we did not find an association between renal replacement therapy and mortality.1,25 While there is an association between renal replacement therapy and mortality in ICU patients, its status in cardiac surgery patients with prolonged ICU stays is less clear.26 While Ryan and colleagues found an association between renal replacement therapy and hospital mortality in patients staying > 14 days, they did not find it in patients staying > 28 days.1 Other studies of prolonged ICU stays for cardiac surgery patients have also failed to find an association between renal replacement therapy and mortality.5,6,9 Importantly, practice that expedites liberation from mechanical ventilation, such as fast tracking, daily spontaneous breathing trials, extubation to noninvasive respiratory support, and pulmonary rehabilitation may all have potential to limit mechanical ventilation duration and improve hospital survival and deserve further study.27–29

Median (IQR) survival in hospital survivors was 10.7 (0.7) years, which is generally better than previously reported, but similar to that reported by Silberman and colleagues.2,4,6,8,11,12 Differences between these studies may relate to different patient populations within the cardiac surgery ICUs, definitions of prolonged ICU stays, or eras of care. Further study is needed to clarify these discrepancies. We found that cardiac transplantation and obesity were associated with the least risk of dying, while smoking, lung disease, and postoperative pneumonia were independently associated with increased hazard of dying. The obesity paradox, where obesity is protective, has been previously observed in cardiac surgery patients.30

Strengths and Limitations

There are several limitations of this study. This is a single center study, and our patient population and processes of care may differ from other centers, limiting its generalizability. Notably, we do fewer coronary bypass operations and more aortic reconstructions and ventricular assist device insertions than do many other centers. Second, we did not have laboratory values for about one-third of patients (preceded EHR implementation). However, we were able to compensate for this by binning values and including missing data as an extra bin.20,21

The main strength of this study is that we were able to combine disparate records to assess a large number of potential factors associated with both operative and long-term mortality. This produced models that had good to very good discrimination. By producing models at 7, 14, 21, and 28 days to predict operative mortality and a model at discharge, it may help to provide objective data to facilitate conversations with patients and their families. However, further studies to externally validate these models should be conducted.

CONCLUSIONS

We found that longer prolonged ICU stays are associated with both operative and late mortality. Receiving mechanical ventilation on days 7, 14, 21, or 28 was strongly associated with operative mortality.

Supplementary Data

eAPPENDIX 1.

Univariate Analysis of Factors Associated With Mortality for Patients With Intensive Care Unit Length of Stay ≥ 7 Daysa

At discharge At follow-up
Variables Survived (n = 1049) Deceased (n = 125) P value Survived (n = 754) Deceased (n = 420) P value
Preoperative No. (%) No. (%) No. (%) No. (%)
Sex, male 654 (62) 69 (55) .14 470 (62) 253 (60) .49
Race, White 889 (85) 102 (82) .36 632 (84) 359 (86) .50
Smoker 416 (40) 56 (45) .29 261 (35) 211 (50) < .001
Diabetes mellitus 287 (27) 44 (35) .07 190 (25) 141 (34) .003
Renal failure 268 (26) 44 (35) .02 188 (25) 124 (30) .01
Dialysis 58 (6) 15 (12) .01 41(5) 32 (8) .17
Hypertension 689 (66) 81 (65) .84 478 (63) 292 (70) .04
Cerebrovascular accident 93 (9) 17 (13) .10 65 (9) 45 (11) .25
Cerebrovascular disease 159 (15) 31 (25) .01 115 (15) 75 (18) .25
Infectious endocarditis 88 (9) 19 (15) .02 62 (8) 45 (11) .17
Chronic lung disease .01 .07
 Mild 130 (12) 18 (14) 86 (11) 62 (15)
 Moderate or severe 120 (11) 25 (20) 86 (11) 59 (14)
Peripheral vascular disease 120 (11) 23 (18) .03 73 (10) 70 (17) .001
Myocardial infarction 321 (31) 38 (30) .99 212 (28) 147 (35) .02
Congestive heart failure 530 (51) 64 (51) .93 365 (48) 229 (55) .05
Cardiogenic shock 129 (12) 15 (12) .99 100 (13) 44 (11) .19
Resuscitation 8 (1) 2 (2) .29 7 (1) 3 (1) .99
Preoperative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Age, y 61 (14) 64 (12) .02 59 (14) 65 (13) < .001
Weight, kg 85.1 (22.9) 85.2 (22.1) .93 86.2 (23.0) 81.9 (22.1) < .001
Body mass index 27.3 (6.9) 27.5 (7.2) .74 27.8 (7.1) 26.3 (6.7) < .001
Ejection fraction 41 (21) 43 (19) .25 41 (21) 41 (21) .77
Creatinine, mg/dL 1.50 (1.31) 1.85 (1.77) .09 1.46 (1.26) 1.71 (1.58) .04
Bilirubin, mg/dL 0.8 (1.1) 1.7 (4.7) .09 0.9 (2.0) 0.9 (1.6) .68
Hemoglobin, g/dL 11.8 (2.3) 11.4 (2.5) .08 12.0 (2.3) 11.5 (2.2) .004
Hematocrit, % 35.1 (6.6) 34.2 (7.0) .23 35.5 (6.7) 34.1 (6.5) .01
White blood cells, 103/μL 9.1 (4.7) 10.4 (9.5) .23 9.4 (5.8) 9.0 (4.8) .37
Operative No. (%) No. (%) No. (%) No. (%)
Procedures
 Coronary artery bypass grafting 233 (22) 26 (21) .82 148 (20) 111 (26) .008
 Valve 566 (54) 85 (68) .003 408 (54) 243 (58) .22
 Aortic 310 (30) 29 (23) .15 230 (31) 109 (26) .11
 Ventricular-assist device 200 (19) 13 (10) .02 136 (18) 77 (18) .94
 Transplant 87 (8) 5 (4) .11 72 (10) 20 (5) .003
 Other 30 (3) 8 (6) .05 29 (4) 9 (2) .12
Hypothermic circulatory arrest 174 (17) 12 (10) .05 126 (17) 60 (14) .32
No. procedures .80 .71
 1 710 (68) 87 (70) 510 (68) 287 (68)
 2 303 (29) 35 (28) 221 (29) 117 (28)
 3 36 (3) 3 (2) 23 (3) 16 (4)
Return to operating room 20 (2) 0 (0) .26 12 (2) 8 (2) .82
Operative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Cross-clamp, min 127 (71) 140 (87) .19 130 (71) 127 (77) .67
Perfusion, min 160 (88) 180 (105) .046 163 (89) 160 (92) .62
Operative Median (IQR) Median (IQR) Median (IQR) Median (IQR)
Transfusion
 Red cell 4 (2–7) 5 (2–8) .13 4 (2–7) 4 (2–8) .12
 Plasma 3 (0–7) 4 (0–7) .33 4 (0–7) 3 (0–7) .97
 Platelet 2 (2–5) 2 (2–6) .56 2 (2–5) 2 (2–5) .33
Cryoprecipitate 0 (0–0) 0 (0–1) .02 0 (0–1) 0 (0–1) .78
Postoperative day 7 No. (%) No. (%) No. (%) No. (%)
Vasopressor 99 (16) 27 (33) < .001 84 (18) 42 (18) .83
Ventilator support 234 (22) 60 (48) < .001 187 (25) 107 (26) .83
Renal replacement therapy 65 (6%) 19 (15) .001 51 (7) 33 (8) .48
Transfusion
Red cell 132 (21) 24 (29) .12 105 (22) 51 (22) .92
Plasma 62 (10) 10 (12) .56 46 (10) 26 (11) .51
Platelet 52 (8) 10 (12) .27 38 (8) 24 (11) .26
Cryoprecipitate transfusion 5 (1) 1 (1) .52 5 (1) 1 (< 1) .67
Pneumonia 118 (18) 117 (29) < .001
Postoperative day 7 Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Creatinine, mg/dL 1.68 (1.26) 1.94 (1.10) .08 1.65 (1.18) 1.82 (1.36) .10
Sodium, mmol/L 140 (5.9) 140 (6.6) .83 140 (6) 140 (6) .59
Chloride, mmol/L 105 (6.9) 104 (6.7) .33 104 (7) 104 (7) .85
Hemoglobin, g/dL 10.3 (2.2) 10.8 (4.0) .11 10.3 (2.8) 10.6 (1.6) .15
Hematocrit, % 29.9 (4.6) 29.8 (4.5) .91 29.5 (4.4) 30.7 (4.8) .001
Bilirubin, mg/dL 1.7 (2.5) 4.3 (7.3) .01 2.0 (3.7) 2.0 (3.2) .93
Alanine transaminase, U/L 125 (403) 248 (423) .03 167 (478) 86 (144) .004
Alkaline phosphatase, U/L 93 (57) 105 (90) .14 96 (66) 92 (53) .53
White blood cells, 103/μL 12.1 (5.0) 16.5 (9.6) < .001 12.8 (6.1) 12.1 (5.5) .16
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a

Data not available for all variables for all patients; for continuous variables with data missing, available data used from total no. patients for survival at discharge, mortality at discharge, survival at follow-up, mortality at follow-up: age, weight, body mass index (1049, 125, 754, 420, respectively); ejection fraction (989, 120, 705, 410, respectively); preop creatinine, bilirubin, hemoglobin, hematocrit, white blood cells (625, 82, 478, 229, respectively); cross-clamp time (753, 88, 557, 284, respectively); perfusion time (1006, 118, 724, 400, respectively); day 7 creatinine, sodium, chloride, white blood cells (624, 81, 476, 229, respectively); day 7 hemoglobin (622, 80, 474, 228, respectively); day 7 hematocrit (622, 81, 223, 61, respectively), day 7 bilirubin, alanine transaminase, alkaline phosphatase (481, 64, 376, 169, respectively).

eAPPENDIX 2.

Univariate Analysis of Factors Associated With Operative and Late Mortality for Patients With Intensive Care Unit Length of Stay ≥ 14 Daysa

At discharge At follow-up
Variables Survived (n = 1049) Deceased (n = 125) P value Deceased (n = 420) Deceased (n = 420) P value
Preoperative No. (%) No. (%) No. (%) No. (%)
Sex, male 205 (65) 35 (50) .03 142 (62) 98 (62) .99
Race, White 258 (82) 57 (81) .99 180 (79) 135 (85) .11
Smoker 139 (44) 33 (47) .69 96 (42) 76 (48) .25
Diabetes mellitus 88 (28) 26 (37) .15 57 (25) 57 (36) .02
Renal failure 106 (34) 26 (37) .58 80 (35) 52 (33) .66
Dialysis 16 (5) 8 (11) .06 14 (6) 10 (6) .99
Hypertension 203 (64) 44 (63) .89 138 (61) 109 (69) .11
Cerebrovascular accident 34 (11) 12 (17) .15 30 (13) 16 (10) .43
Cerebrovascular disease 57 (18) 21 (30) .03 44 (19) 34 (21) .61
Infectious endocarditis 26 (8) 11 (16) .07 18 (8) 19 (12) .22
Chronic lung disease .06 .98
 Mild 39 (12)
 Moderate or severe 35 (11) 15 (21) 29 (13) 21 (13)
Peripheral vascular disease 39 (12) 10 (14) .69 19 (8) 30 (19) .003
Myocardial infarction 110 (35) 20 (29) .33 75 (33) 55 (35) .74
Congestive heart failure 184 (58) 38 (54) .59 126 (55) 96 (61) .30
Cardiogenic shock 66 (21) 10 (14) .28 53 (23) 23 (15) .04
Resuscitation 6 (2) 2 (3) .64 5 (2) 3 (2) .99
Preoperative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Age, y 62 (15) 63 (13) .62 59 (15) 67 (12) < .001
Weight, kg 84.0 (24.5) 86.0 (22.9) .53 86.1 (24.2) 82.0 (24.1) .10
Body mass index 26.6 (6.8) 28.4 (7.6) .06 27.5 (7.1) 26.1 (6.6) .08
Ejection fraction 38 (22) 43 (21) .10 38 (22) 41 (21) .30
Creatinine, mg/dL 1.55 (1.33) 2.13 (1.97) .37 1.59 (1.30) 1.80 (1.78) .34
Bilirubin, mg/dL 0.9 (1.0) 1.1 (1.2) .14 0.8 (0.7) 1.0 (1.4) .20
Hemoglobin, mg/dL 11.7 (2.6) 11.2 (2.3) .25 11.9 (2.6) 11.1 (2.4) .04
Hematocrit, % 34.5 (7.7) 33.5 (6.6) .45 35.2 (7.6) 32.9 (7.0) .04
White blood cells, 103/μL 10.1 (6.5) 11.0 (11.4) .52 11.0 (8.3) 9.1 (6.5) .09
Operative No. (%) No. (%) No. (%) No. (%)
Procedure
 Coronary artery bypass grafting 62 (20) 13 (19) .99 43 (19) 32 (20) .79
 Valve 154 (49) 45 (64) .02 114 (50) 85 (48) .47
 Aortic 100 (32) 18 (26) .39 69 (30) 49 (31) .91
 Ventricular-assist device 86 (27) 7 (10) .002 56 (25) 38 (23) .81
 Transplant 22 (7) 4 (6) .99 17 (8) 9 (6) .54
 Other 9 (3) 5 (7) .15 12 (5) 2 (1) .05
Hypothermic circulatory arrest 53 (17) 9 (13) .48 36 (16) 26 (17) .89
No. procedures .78 .98
 1 212 (67) 50 (71) 155 (68) 107 (68)
 2 93 (29) 18 (26) 65 (29) 46 (29)
 3 11 (4) 2 (3) 8 (4) 5 (3)
Return to operating room 17 (5) 0 (0) .05 10 (4) 7 (4) .99
Operative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Cross-clamp, min 134 (73) 148 (89) .26 133 (73) 144 (80) .28
Perfusion, min 188 (96) 168 (101) .15 171 (101) 173 (99) .81
Operative Median (IQR) Median (IQR) Median (IQR) Median (IQR)
Transfusion
 Red cell 6 (3–8) 5.5 (2–9) .91 5 (2–8) 6 (3–9) .10
 Plasma 4 (1–8) 4.5 (1–7) .94 4 (0–8) 4 (2–8) .30
 Platelet 3 (0–6) 4 (1–6) .36 3 (0–5) 4 (1–7) .15
 Cryoprecipitate 0 (0–1) 0 (0–2) .19 0 (0–1) 0 (0–2) .08
Postoperative day 14 No. (%) No. (%) No. (%) No. (%)
Vasopressor 32 (20) 14 (34) .06 29 (23) 17 (23) .99
Ventilator support 51 (16) 29 (41) < .001 52 (23) 28 (18) .25
Renal replacement therapy 41 (13) 14 (20) .13 36 (16) 19 (12) .37
Transfusion
 Red cell 51 (32) 15 (37) .58 43 (34) 23 (31) .76
 Plasma 28 (18) 7 (17) .99 23 (18) 12 (16) .85
 Platelet 21 (13) 6 (15) .80 17 (14) 10 (14) .99
 Cryoprecipitate 4 (3) 1 (2) .99 4 (3) 1 (1) .65
Postoperative pneumonia 55 (32) 59 (41) .13
Postoperative day 14 Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Creatinine, mg/dL 1.89 (1.29) 2.03 (1.38) .54 1.93 (1.38) 1.91 (1.17) .94
Sodium, mmol/L 141 (6) 140 (6) .16 141 (6) 141 (6) .78
Chloride, mmol/L 107 (7) 103 (7) .004 106 (7) 106 (8) .76
Hemoglobin, g/dL 10.1 (1.5) 9.7 (1.3) .20 9.9 (1.4) 10.2 (1.6) .09
Hematocrit, % 29.3 (4.4) 28.3 (4.3) .19 28.6 (4.3) 29.9 (4.5) .05
Bilirubin, mg/dL 2.0 (2.3) 4.5 (6.2) .03 2.6 (3.8) 2.4 (3.4) .74
Alanine transaminase, U/L 106 (257) 283 (613) .12 159 (370) 115 (376) .50
Alkaline phosphatase (U/L) 147 (92) 126 (49) .10 145 (86) 136 (83) .56
White blood cells, 103/μL 15.2 (7.0) 23.6 (17.0) .004 18.2 (11.9) 14.6 (6.4) .007
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a

Data not available for all variables for all patients; for continuous variables with data missing, available data used from total no. patients for survival at discharge, mortality at discharge, survival at follow-up, mortality at follow-up: age, weight, body mass index (316, 70, 228, 158, respectively); ejection fraction (291, 67, 208, 150, respectively); preop creatinine, bilirubin, hemoglobin, hematocrit, white blood cells (159, 41, 126, 74, respectively); cross-clamp time (203, 51, 154, 150, respectively); perfusion time (299, 65, 213, 151, respectively); day 14 creatinine, sodium, chloride (155, 40, 124, 71, respectively), day 14 hemoglobin, white blood cells (155, 39, 124, 70, respectively); day 14 hematocrit (40, 15, 35, 19, respectively); day 14 bilirubin, alanine transaminase, alkaline phosphatase (113, 32, 97, 48, respectively).

eAPPENDIX 3.

Univariate Analysis of Factors Associated With Operative and Late Mortality for Patients With Intensive Care Unit Length of Stay ≥ 21 Daysa

At discharge At follow-up
Variables Survived (n = 1049) Deceased (n = 125) P value Survived (n = 754) Deceased (n = 420) P value
Preoperative No. (%) No. (%) No. (%) No. (%)
Sex, male 103 (66) 23 (52) .11 66 (63) 60 (63) .99
Race, White 131 (83) 40 (91) .34 89 (85) 82 (85) .99
Smoker 69 (44) 22 (50) .50 43 (41) 48 (50) .21
Diabetes mellitus 46 (29) 15 (34) .58 29 (28) 32 (33) .44
Renal failure 56 (36) 14 (32) .72 35 (33) 35 (37) .66
Dialysis 12 (8) 4 (9) .76 7 (7) 9 (9) .60
Hypertension 98 (62) 28 (64) .99 56 (53) 70 (73) .005
Cerebrovascular accident 19 (12) 9 (21) .22 17 (16) 11 (12) .42
Cerebrovascular disease 32 (20) 15 (34) .07 23 (22) 24 (25) .62
Infectious endocarditis 12 (8) 8 (18) .049 7 (7) 13 (14) .16
Chronic lung disease .09 .51
 Mild 22 (14) 8 (18) 17 (16) 13 (14)
 Moderate or severe 15 (10) 9 (21) 10 (10) 14 (15)
Peripheral vascular disease 13 (8) 7 (16) .16 8 (8) 12 (13) .35
Myocardial infarction 51 (33) 12 (27) .58 31 (30) 32 (33) .74
Congestive heart failure 99 (63) 20 (46) .04 59 (56) 60 (63) .39
Cardiogenic shock 35 (22) 3 (7) .03 26 (25) 12 (13) .03
Resuscitation 4 (3) 1 (2) .99 3 (3) 2 (2) .99
Preoperative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Age, y 62 (15) 63 (12) .73 59 (16) 67 (12)
Weight, kg 84.4 (26.6) 86.9 (21.0) .56 87.9 (25.0) 81.7 (25.6) .08
Body mass index 26.2 (6.5) 28.8 (7.7) .03 27.6 (7.1) 25.9 (6.4) .07
Ejection fraction 37 (23) 44 (22) .09 38 (23) 39 (22) .72
Creatinine, mg/dL 1.71 (1.69) 1.99 (1.50) .45 1.70 (1.20) 1.89 (2.06) .56
Bilirubin, mg/dL 0.8 (1.0) 1.1 (1.3) .34 0.7 (0.5) 1.1 (1.5) .11
Hemoglobin, g/dL 11.5 (2.6) 11.1 (2.4) .48 11.8 (2.5) 11.0 (2.6) .11
Hematocrit, % 34.2 (7.7) 33.6 (7.0) .70 35.2 (7.1) 32.6 (7.8) .08
White blood cells, 103/μL 9.9 (6.6) 9.5 (4.2) .78 10.1 (4.9) 9.4 (7.2) .55
Operative No. (%) No. (%) No. (%) No. (%)
Procedure
 Coronary artery bypass grafting 27 (17) 7 (16) .99 18 (17) 16 (17) .99
 Valve 69 (44) 29 (66) .01 48 (46) 50 (52) .40
 Aortic 45 (29) 13 (30) .99 28 (27) 30 (31) .53
 Ventricular-assist device 51 (33) 4 (9 .002 31 (30) 24 (25) .53
 Transplant 12 (8) 4 (9) .76 9 (9) 7 (7) .80
 Other 4 (3) 2 (5) .61 5 (5) 1 (1) .22
Hypothermic circulatory arrest 19 (12) 9 (21) .22 12 (11) 16 (17) .31
No. procedures .26 .31
 1 113 (72) 29 (66) 74 (71) 68 (71)
 2 39 (25) 15 (34) 30 (29) 24 (25)
 3 5 (3) 0 (0) 1 (1) 4 (4)
Return to operating room 13 (8) 0 (0) .08 8 (8) 5 (5) .57
Operative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Cross-clamp, min 128 (70) 172 (91) .006 132 (71) 149 (86) .22
Perfusion, min 158 (87) 205 (100) .003 162 (83) 176 (99) .31
Operative Median (IQR) Median (IQR) Median (IQR) Median (IQR)
Transfusion
 Red cell 6 (2–9) 5.5 (2–8) .86 5 (2–8) 6.5 (3–10) .04
 Plasma 4 (0–9) 4 (1–8) .76 4 (0–9) 4.5 (0–9) .36
 Platelet 2 (1–6) 3 (0–6) .86 2 (0–5) 4 (1–8) .05
 Cryoprecipitate 0 (0–1) 0 (0–2) .55 0 (0–1) 0 (0–2) .08
Postoperative day 21 No. (%) No. (%) No. (%) No. (%)
Vasopressor 20 (27) 9 (32) .63 18 (33) 11 (24) .38
Ventilator support 23 (15) 19 (43) < .001 25 (24) 17 (18) .30
Renal replacement therapy 19 (12) 11 (25) .05 20 (19) 10 (10) .11
Transfusion
 Red cell 29 (40) 12 (43) .82 25 (46) 16 (35) .31
 Plasma 18 (25) 4 (14) .30 14 (26) 8 (17) .35
 Platelet 13 (18) 4 (14) .77 8 (15) 9 (20) .60
 Cryoprecipitate 4 (6) 0 (0) .57 3 (6) 1 (2) .62
Postoperative pneumonia 23 (32) 37 (44) .14
Postoperative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Creatinine, mg/dL 1.63 (1.25) 2.09 (1.48) .15 1.80 (1.45) 1.73 (1.16) .79
Sodium, mmol/L 142 (6) 141 (5) .40 141 (6) 142 (6) .53
Chloride, mmol/L 107 (6) 105 (5) .16 106 (6) 107 (6) .66
Hemoglobin, g/dL 9.8 (3.0) 9.4 (1.3) .47 9.4 (1.2) 10.0 (3.8) .29
Hematocri, % 28.1 (4.5) 27.6 (4.0) .53 27.3 (4.0) 29.1 (4.7) .02
Bilirubin, mg/dL 1.6 (1.6) 2.6 (3.8) .20 2.0 (2.5) 2.0 (3.0) .95
Alanine transaminase, U/L 71 (66) 83 (109) .56 87 (101) 56 (42) .07
Alkaline phosphatase, U/L 146 (95) 134 (27) .74 160 (95) 116 (66) .11
White blood cells, 103/μL 11.2 (4.6) 14.3 (5.2) .006 12.2 (4.9) 12.2 (5.2) .99
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a

Data not available for all variables for all patients; for continuous variables with data missing, available data used from total no. patients for survival at discharge, mortality at discharge, survival at follow-up, mortality at follow-up: age, weight, body mass index (157, 44, 105, 96, respectively); ejection fraction (149, 42, 99, 92, respectively); preop creatinine, bilirubin, hemoglobin, hematocrit, white blood cells (73, 28, 55, 46, respectively); cross-clamp time (90, 32, 66, 56, respectively); perfusion time (151, 42, 99, 94, respectively); day 21 creatinine (58, 26, 49, 35, respectively); day 21 sodium, chloride, white blood cells (65, 27, 53, 39, respectively); day 21 hemoglobin (65, 26, 52, 39, respectively); day 21 hematocrit (19, 11, 19, 11, respectively); day 21 bilirubin (45, 27, 45, 27, respectively); day 21 alanine transaminase, alkaline phosphatase (44, 27, 44, 27, respectively).

eAPPENDIX 4.

Univariate Analysis of Factors Associated With Operative and Late Mortality for Patients With Intensive Care Unit Length of Stay ≥ 28 Daysa

At discharge At follow-up
Variables Survived (n = 1049) Deceased (n = 125) P value Survived (n = 754) Deceased (n = 420) P value
Preoperative No. (%) No. (%) No. (%) No. (%)
Sex, male 28 (54) 11 (39) .25 21 (54) 18 (44) .50
Race, White 45 (87) 26 (93) .48 34 (87) 37 (90) .73
Smoker 25 (48) 16 (57) .49 17 (44) 24 (59) .26
Diabetes mellitus 13 (25) 12 (43) .13 13 (33) 12 (29) .81
Renal failure 19 (37) 9 (32) .81 13 (33) 15 (37) .82
Dialysis 4 (8) 3 (11) .69 2 (5) 5 (12) .43
Hypertension 33 (64) 19 (68) .81 22 (56) 30 (73) .16
Cerebrovascular accident 5 (10) 5 (18) .31 5 (13) 5 (12) .99
Cerebrovascular disease 10 (19) 9 (32) .27 8 (21) 11 (27) .60
Infectious endocarditis 2 (4) 6 (21) .02 4 (10) 4 (10) .99
Chronic lung disease .01 .44
 Mild 5 (10) 4 (14) 5 (13) 4 (10)
 Moderate or severe 2 (4) 7 (25) 6 (15) 3 (7)
Peripheral vascular disease 3 (6) 4 (14) .23 3 (8) 4 (10) .99
Myocardial infarction 16 (31) 7 (25) .80 12 (31) 11 (27) .81
Congestive heart failure 34 (65) 14 (50) .23 22 (56) 26 (63) .65
Cardiogenic shock 13 (25) 2 (7) .07 10 (26) 5 (12) .16
Resuscitation 1 (2) 1 (4) .99 2 (5) 0 (0) .23
Preoperative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Age, y 62 (16) 63 (11) .72 59 (16) 65 (12) .05
Weight, kg 77.9 (28.0) 81.6 (17.8) .53 84.7 (26.4) 74.0 (22.3) .05
Body mass index 25.6 (6.6) 26.8 (5.5) .39 27.3 (6.5) 24.9 (5.9) .08
Ejection fraction 40 (23) 43 (23) .59 39 (24) 43 (21) .42
Creatinine, mg/dL 1.70 (1.16) 1.87 (1.23) .65 1.76 (1.13) 1.78 (1.24) .95
Bilirubin, mg/dL 0.6 (0.4) 1.0 (1.3) .22 0.6 (0.5) 0.9 (1.1) .33
Hemoglobin, g/dL 11.5 (2.0) 11.3 (2.3) .79 11.5 (2.4) 11.3 (1.8) .71
Hematocrit, % 34.1 (6.0) 33.8 (6.4) .84 34.3 (6.6) 33.7 (5.7) .74
White blood cells, 103/μL 8.6 (3.8) 9.2 (3.8) .62 8.8 (2.7) 8.9 (4.6) .92
Operative No. (%) No. (%) No. (%) No. (%)
Procedures
 Coronary artery bypass grafting 11 (21) 4 (14) .56 7 (18) 8 (20) .99
 Valve 20 (39) 19 (68) .02 18 (46) 21 (52) .66
 Aortic 10 (19) 7 (25) .58 8 (21) 9 (22) .99
 Ventricular-assist device 18 (37) 2 (7) .007 11 (28) 9 (22) .61
 Transplant 7 (14) 3 (11) .99 6 (15) 4 (10) .51
 Other 0 (0) 2 (7) .12 2 (5) 0 (0) .23
Hypothermic circulatory arrest 7 (13) 7 (25) .23 4 (10) 10 (24) .14
No. procedures .45 .34
 1 40 (77) 19 (68) 27 (69) 32 (78)
 2 11 (21) 9 (32) 12 (31) 8 (20)
 3 1 (2) 0 (0) 0 (0) 1 (2)
Return to operating room 7 (14) 0 (0) .09 5 (13) 2 (5) .26
Operative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Cross-clamp, min 126 (69) 184 (103) .03 146 (88) 154 (91) .76
Perfusion, min 148 (78) 208 (113) .01 170 (95) 166 (96) .84
Operative Median (IQR) Median (IQR) Median (IQR) Median (IQR)
Transfusion
 Red cell 7 (4–9) 5 (2–8.8) .20 5 (2–8) 8 (6–10) .003
 Plasma 4 (1–10) 4 (1–8) .33 4 (0–9) 4 (2–10) .23
 Platelet 3 (2–7) 3 (0–4) .25 2 (0–5) 3 (2–8) .17
 Cryoprecipitate 0 (0–2) 0 (0–1) .32 0 (0–1) 0 (0–2) .25
Postoperative No. (%) No. (%) No. (%) No. (%)
Vasopressor 3 (11) 4 (22) .42 3 (14) 4 (17) .99
Ventilator support 9 (17) 14 (50) .004 13 (33) 10 (24) .46
Renal replacement therapy 8 (15) 7 (25) .37 9 (23) 6 (15) .40
Transfusion
 Red cell 14 (54) 7 (39) .37 10 (48) 11 (48) .99
 Plasma 5 (19) 3 (17) .99 5 (24) 3 (13) .45
 Platelet 4 (15) 3 (17) .99 3 (14) 4 (17) .99
 Cryoprecipitate 1 (4) 0 (0) .99 0 (0) 1 (4) .99
Postoperative pneumonia 9 (45) 17 (53 .78
Postoperative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Creatinine, mg/dL 1.66 (1.14) 1.88 (1.05) .58 1.73 (1.01) 1.83 (1.20) .79
Sodium, mmol/L 141 (4) 141 (4) .96 141 (4) 141 (4) .58
Chloride, mmol/L 104 (4) 102 (4) .30 103 (4) 103 (4) .69
Hemoglobin g/dL 9.5 (1.3) 9.6 (1.2) .88 9.6 (1.2) 9.5 (1.3) .84
Hematocrit, % 27.9 (3.4) 27.3 (3.1) .62 27.6 (3.4) 27.7 (3.1) .98
Bilirubin, mg/dL 0.8 (0.5) 3.3 (5.4) .15 2.9 (5.1) 0.8 (0.5) .18
Alanine transaminase, U/L 49 (37) 94 (122) .25 83 (116) 54 (35) .42
Alkaline phosphatase, U/L 131 (72) 133 (54) .92 139 (66) 122 (62) .44
White blood cells, 103/μL 11.6 (4.2) 11.9 (3.4) .79 11.8 (3.6) 11.7 (4.0) .91
Open in a new tab
a

Data not available for all variables for all patients; for continuous variables with data missing, available data used from total no. patients for survival at discharge, mortality at discharge, survival at follow-up, mortality at follow-up: age, weight, body mass index (52, 28, 39, 41, respectively); ejection fraction (51, 28, 39, 40, respectively); preop creatinine, bilirubin, hemoglobin, hematocrit, white blood cells (26, 18, 21, 23, respectively); cross-clamp time (28, 19, 26, 21, respectively); perfusion time (51, 26, 36, 41, respectively); day 28 creatinine, sodium, chloride, hemoglobin, hematocrit, white blood cells (20, 17, 19, 18, respectively); day 28 bilirubin, alanine transaminase, alkaline phosphatase (14, 12, 14, 12, respectively).

Footnotes

Disclaimer

The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the US Government, or any of its agencies.

Ethics and consent

This study was approved by the University of Michigan Health System Institutional Review Board (HUM00086820 5/20/2014), which waived informed consent.

Author disclosures

The authors report no actual or potential conflicts of interest or outside sources of funding with regard to this article.

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Associated Data

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Supplementary Materials

eAPPENDIX 1.

Univariate Analysis of Factors Associated With Mortality for Patients With Intensive Care Unit Length of Stay ≥ 7 Daysa

At discharge At follow-up
Variables Survived (n = 1049) Deceased (n = 125) P value Survived (n = 754) Deceased (n = 420) P value
Preoperative No. (%) No. (%) No. (%) No. (%)
Sex, male 654 (62) 69 (55) .14 470 (62) 253 (60) .49
Race, White 889 (85) 102 (82) .36 632 (84) 359 (86) .50
Smoker 416 (40) 56 (45) .29 261 (35) 211 (50) < .001
Diabetes mellitus 287 (27) 44 (35) .07 190 (25) 141 (34) .003
Renal failure 268 (26) 44 (35) .02 188 (25) 124 (30) .01
Dialysis 58 (6) 15 (12) .01 41(5) 32 (8) .17
Hypertension 689 (66) 81 (65) .84 478 (63) 292 (70) .04
Cerebrovascular accident 93 (9) 17 (13) .10 65 (9) 45 (11) .25
Cerebrovascular disease 159 (15) 31 (25) .01 115 (15) 75 (18) .25
Infectious endocarditis 88 (9) 19 (15) .02 62 (8) 45 (11) .17
Chronic lung disease .01 .07
 Mild 130 (12) 18 (14) 86 (11) 62 (15)
 Moderate or severe 120 (11) 25 (20) 86 (11) 59 (14)
Peripheral vascular disease 120 (11) 23 (18) .03 73 (10) 70 (17) .001
Myocardial infarction 321 (31) 38 (30) .99 212 (28) 147 (35) .02
Congestive heart failure 530 (51) 64 (51) .93 365 (48) 229 (55) .05
Cardiogenic shock 129 (12) 15 (12) .99 100 (13) 44 (11) .19
Resuscitation 8 (1) 2 (2) .29 7 (1) 3 (1) .99
Preoperative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Age, y 61 (14) 64 (12) .02 59 (14) 65 (13) < .001
Weight, kg 85.1 (22.9) 85.2 (22.1) .93 86.2 (23.0) 81.9 (22.1) < .001
Body mass index 27.3 (6.9) 27.5 (7.2) .74 27.8 (7.1) 26.3 (6.7) < .001
Ejection fraction 41 (21) 43 (19) .25 41 (21) 41 (21) .77
Creatinine, mg/dL 1.50 (1.31) 1.85 (1.77) .09 1.46 (1.26) 1.71 (1.58) .04
Bilirubin, mg/dL 0.8 (1.1) 1.7 (4.7) .09 0.9 (2.0) 0.9 (1.6) .68
Hemoglobin, g/dL 11.8 (2.3) 11.4 (2.5) .08 12.0 (2.3) 11.5 (2.2) .004
Hematocrit, % 35.1 (6.6) 34.2 (7.0) .23 35.5 (6.7) 34.1 (6.5) .01
White blood cells, 103/μL 9.1 (4.7) 10.4 (9.5) .23 9.4 (5.8) 9.0 (4.8) .37
Operative No. (%) No. (%) No. (%) No. (%)
Procedures
 Coronary artery bypass grafting 233 (22) 26 (21) .82 148 (20) 111 (26) .008
 Valve 566 (54) 85 (68) .003 408 (54) 243 (58) .22
 Aortic 310 (30) 29 (23) .15 230 (31) 109 (26) .11
 Ventricular-assist device 200 (19) 13 (10) .02 136 (18) 77 (18) .94
 Transplant 87 (8) 5 (4) .11 72 (10) 20 (5) .003
 Other 30 (3) 8 (6) .05 29 (4) 9 (2) .12
Hypothermic circulatory arrest 174 (17) 12 (10) .05 126 (17) 60 (14) .32
No. procedures .80 .71
 1 710 (68) 87 (70) 510 (68) 287 (68)
 2 303 (29) 35 (28) 221 (29) 117 (28)
 3 36 (3) 3 (2) 23 (3) 16 (4)
Return to operating room 20 (2) 0 (0) .26 12 (2) 8 (2) .82
Operative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Cross-clamp, min 127 (71) 140 (87) .19 130 (71) 127 (77) .67
Perfusion, min 160 (88) 180 (105) .046 163 (89) 160 (92) .62
Operative Median (IQR) Median (IQR) Median (IQR) Median (IQR)
Transfusion
 Red cell 4 (2–7) 5 (2–8) .13 4 (2–7) 4 (2–8) .12
 Plasma 3 (0–7) 4 (0–7) .33 4 (0–7) 3 (0–7) .97
 Platelet 2 (2–5) 2 (2–6) .56 2 (2–5) 2 (2–5) .33
Cryoprecipitate 0 (0–0) 0 (0–1) .02 0 (0–1) 0 (0–1) .78
Postoperative day 7 No. (%) No. (%) No. (%) No. (%)
Vasopressor 99 (16) 27 (33) < .001 84 (18) 42 (18) .83
Ventilator support 234 (22) 60 (48) < .001 187 (25) 107 (26) .83
Renal replacement therapy 65 (6%) 19 (15) .001 51 (7) 33 (8) .48
Transfusion
Red cell 132 (21) 24 (29) .12 105 (22) 51 (22) .92
Plasma 62 (10) 10 (12) .56 46 (10) 26 (11) .51
Platelet 52 (8) 10 (12) .27 38 (8) 24 (11) .26
Cryoprecipitate transfusion 5 (1) 1 (1) .52 5 (1) 1 (< 1) .67
Pneumonia 118 (18) 117 (29) < .001
Postoperative day 7 Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Creatinine, mg/dL 1.68 (1.26) 1.94 (1.10) .08 1.65 (1.18) 1.82 (1.36) .10
Sodium, mmol/L 140 (5.9) 140 (6.6) .83 140 (6) 140 (6) .59
Chloride, mmol/L 105 (6.9) 104 (6.7) .33 104 (7) 104 (7) .85
Hemoglobin, g/dL 10.3 (2.2) 10.8 (4.0) .11 10.3 (2.8) 10.6 (1.6) .15
Hematocrit, % 29.9 (4.6) 29.8 (4.5) .91 29.5 (4.4) 30.7 (4.8) .001
Bilirubin, mg/dL 1.7 (2.5) 4.3 (7.3) .01 2.0 (3.7) 2.0 (3.2) .93
Alanine transaminase, U/L 125 (403) 248 (423) .03 167 (478) 86 (144) .004
Alkaline phosphatase, U/L 93 (57) 105 (90) .14 96 (66) 92 (53) .53
White blood cells, 103/μL 12.1 (5.0) 16.5 (9.6) < .001 12.8 (6.1) 12.1 (5.5) .16
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Data not available for all variables for all patients; for continuous variables with data missing, available data used from total no. patients for survival at discharge, mortality at discharge, survival at follow-up, mortality at follow-up: age, weight, body mass index (1049, 125, 754, 420, respectively); ejection fraction (989, 120, 705, 410, respectively); preop creatinine, bilirubin, hemoglobin, hematocrit, white blood cells (625, 82, 478, 229, respectively); cross-clamp time (753, 88, 557, 284, respectively); perfusion time (1006, 118, 724, 400, respectively); day 7 creatinine, sodium, chloride, white blood cells (624, 81, 476, 229, respectively); day 7 hemoglobin (622, 80, 474, 228, respectively); day 7 hematocrit (622, 81, 223, 61, respectively), day 7 bilirubin, alanine transaminase, alkaline phosphatase (481, 64, 376, 169, respectively).

eAPPENDIX 2.

Univariate Analysis of Factors Associated With Operative and Late Mortality for Patients With Intensive Care Unit Length of Stay ≥ 14 Daysa

At discharge At follow-up
Variables Survived (n = 1049) Deceased (n = 125) P value Deceased (n = 420) Deceased (n = 420) P value
Preoperative No. (%) No. (%) No. (%) No. (%)
Sex, male 205 (65) 35 (50) .03 142 (62) 98 (62) .99
Race, White 258 (82) 57 (81) .99 180 (79) 135 (85) .11
Smoker 139 (44) 33 (47) .69 96 (42) 76 (48) .25
Diabetes mellitus 88 (28) 26 (37) .15 57 (25) 57 (36) .02
Renal failure 106 (34) 26 (37) .58 80 (35) 52 (33) .66
Dialysis 16 (5) 8 (11) .06 14 (6) 10 (6) .99
Hypertension 203 (64) 44 (63) .89 138 (61) 109 (69) .11
Cerebrovascular accident 34 (11) 12 (17) .15 30 (13) 16 (10) .43
Cerebrovascular disease 57 (18) 21 (30) .03 44 (19) 34 (21) .61
Infectious endocarditis 26 (8) 11 (16) .07 18 (8) 19 (12) .22
Chronic lung disease .06 .98
 Mild 39 (12)
 Moderate or severe 35 (11) 15 (21) 29 (13) 21 (13)
Peripheral vascular disease 39 (12) 10 (14) .69 19 (8) 30 (19) .003
Myocardial infarction 110 (35) 20 (29) .33 75 (33) 55 (35) .74
Congestive heart failure 184 (58) 38 (54) .59 126 (55) 96 (61) .30
Cardiogenic shock 66 (21) 10 (14) .28 53 (23) 23 (15) .04
Resuscitation 6 (2) 2 (3) .64 5 (2) 3 (2) .99
Preoperative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Age, y 62 (15) 63 (13) .62 59 (15) 67 (12) < .001
Weight, kg 84.0 (24.5) 86.0 (22.9) .53 86.1 (24.2) 82.0 (24.1) .10
Body mass index 26.6 (6.8) 28.4 (7.6) .06 27.5 (7.1) 26.1 (6.6) .08
Ejection fraction 38 (22) 43 (21) .10 38 (22) 41 (21) .30
Creatinine, mg/dL 1.55 (1.33) 2.13 (1.97) .37 1.59 (1.30) 1.80 (1.78) .34
Bilirubin, mg/dL 0.9 (1.0) 1.1 (1.2) .14 0.8 (0.7) 1.0 (1.4) .20
Hemoglobin, mg/dL 11.7 (2.6) 11.2 (2.3) .25 11.9 (2.6) 11.1 (2.4) .04
Hematocrit, % 34.5 (7.7) 33.5 (6.6) .45 35.2 (7.6) 32.9 (7.0) .04
White blood cells, 103/μL 10.1 (6.5) 11.0 (11.4) .52 11.0 (8.3) 9.1 (6.5) .09
Operative No. (%) No. (%) No. (%) No. (%)
Procedure
 Coronary artery bypass grafting 62 (20) 13 (19) .99 43 (19) 32 (20) .79
 Valve 154 (49) 45 (64) .02 114 (50) 85 (48) .47
 Aortic 100 (32) 18 (26) .39 69 (30) 49 (31) .91
 Ventricular-assist device 86 (27) 7 (10) .002 56 (25) 38 (23) .81
 Transplant 22 (7) 4 (6) .99 17 (8) 9 (6) .54
 Other 9 (3) 5 (7) .15 12 (5) 2 (1) .05
Hypothermic circulatory arrest 53 (17) 9 (13) .48 36 (16) 26 (17) .89
No. procedures .78 .98
 1 212 (67) 50 (71) 155 (68) 107 (68)
 2 93 (29) 18 (26) 65 (29) 46 (29)
 3 11 (4) 2 (3) 8 (4) 5 (3)
Return to operating room 17 (5) 0 (0) .05 10 (4) 7 (4) .99
Operative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Cross-clamp, min 134 (73) 148 (89) .26 133 (73) 144 (80) .28
Perfusion, min 188 (96) 168 (101) .15 171 (101) 173 (99) .81
Operative Median (IQR) Median (IQR) Median (IQR) Median (IQR)
Transfusion
 Red cell 6 (3–8) 5.5 (2–9) .91 5 (2–8) 6 (3–9) .10
 Plasma 4 (1–8) 4.5 (1–7) .94 4 (0–8) 4 (2–8) .30
 Platelet 3 (0–6) 4 (1–6) .36 3 (0–5) 4 (1–7) .15
 Cryoprecipitate 0 (0–1) 0 (0–2) .19 0 (0–1) 0 (0–2) .08
Postoperative day 14 No. (%) No. (%) No. (%) No. (%)
Vasopressor 32 (20) 14 (34) .06 29 (23) 17 (23) .99
Ventilator support 51 (16) 29 (41) < .001 52 (23) 28 (18) .25
Renal replacement therapy 41 (13) 14 (20) .13 36 (16) 19 (12) .37
Transfusion
 Red cell 51 (32) 15 (37) .58 43 (34) 23 (31) .76
 Plasma 28 (18) 7 (17) .99 23 (18) 12 (16) .85
 Platelet 21 (13) 6 (15) .80 17 (14) 10 (14) .99
 Cryoprecipitate 4 (3) 1 (2) .99 4 (3) 1 (1) .65
Postoperative pneumonia 55 (32) 59 (41) .13
Postoperative day 14 Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Creatinine, mg/dL 1.89 (1.29) 2.03 (1.38) .54 1.93 (1.38) 1.91 (1.17) .94
Sodium, mmol/L 141 (6) 140 (6) .16 141 (6) 141 (6) .78
Chloride, mmol/L 107 (7) 103 (7) .004 106 (7) 106 (8) .76
Hemoglobin, g/dL 10.1 (1.5) 9.7 (1.3) .20 9.9 (1.4) 10.2 (1.6) .09
Hematocrit, % 29.3 (4.4) 28.3 (4.3) .19 28.6 (4.3) 29.9 (4.5) .05
Bilirubin, mg/dL 2.0 (2.3) 4.5 (6.2) .03 2.6 (3.8) 2.4 (3.4) .74
Alanine transaminase, U/L 106 (257) 283 (613) .12 159 (370) 115 (376) .50
Alkaline phosphatase (U/L) 147 (92) 126 (49) .10 145 (86) 136 (83) .56
White blood cells, 103/μL 15.2 (7.0) 23.6 (17.0) .004 18.2 (11.9) 14.6 (6.4) .007
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Data not available for all variables for all patients; for continuous variables with data missing, available data used from total no. patients for survival at discharge, mortality at discharge, survival at follow-up, mortality at follow-up: age, weight, body mass index (316, 70, 228, 158, respectively); ejection fraction (291, 67, 208, 150, respectively); preop creatinine, bilirubin, hemoglobin, hematocrit, white blood cells (159, 41, 126, 74, respectively); cross-clamp time (203, 51, 154, 150, respectively); perfusion time (299, 65, 213, 151, respectively); day 14 creatinine, sodium, chloride (155, 40, 124, 71, respectively), day 14 hemoglobin, white blood cells (155, 39, 124, 70, respectively); day 14 hematocrit (40, 15, 35, 19, respectively); day 14 bilirubin, alanine transaminase, alkaline phosphatase (113, 32, 97, 48, respectively).

eAPPENDIX 3.

Univariate Analysis of Factors Associated With Operative and Late Mortality for Patients With Intensive Care Unit Length of Stay ≥ 21 Daysa

At discharge At follow-up
Variables Survived (n = 1049) Deceased (n = 125) P value Survived (n = 754) Deceased (n = 420) P value
Preoperative No. (%) No. (%) No. (%) No. (%)
Sex, male 103 (66) 23 (52) .11 66 (63) 60 (63) .99
Race, White 131 (83) 40 (91) .34 89 (85) 82 (85) .99
Smoker 69 (44) 22 (50) .50 43 (41) 48 (50) .21
Diabetes mellitus 46 (29) 15 (34) .58 29 (28) 32 (33) .44
Renal failure 56 (36) 14 (32) .72 35 (33) 35 (37) .66
Dialysis 12 (8) 4 (9) .76 7 (7) 9 (9) .60
Hypertension 98 (62) 28 (64) .99 56 (53) 70 (73) .005
Cerebrovascular accident 19 (12) 9 (21) .22 17 (16) 11 (12) .42
Cerebrovascular disease 32 (20) 15 (34) .07 23 (22) 24 (25) .62
Infectious endocarditis 12 (8) 8 (18) .049 7 (7) 13 (14) .16
Chronic lung disease .09 .51
 Mild 22 (14) 8 (18) 17 (16) 13 (14)
 Moderate or severe 15 (10) 9 (21) 10 (10) 14 (15)
Peripheral vascular disease 13 (8) 7 (16) .16 8 (8) 12 (13) .35
Myocardial infarction 51 (33) 12 (27) .58 31 (30) 32 (33) .74
Congestive heart failure 99 (63) 20 (46) .04 59 (56) 60 (63) .39
Cardiogenic shock 35 (22) 3 (7) .03 26 (25) 12 (13) .03
Resuscitation 4 (3) 1 (2) .99 3 (3) 2 (2) .99
Preoperative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Age, y 62 (15) 63 (12) .73 59 (16) 67 (12)
Weight, kg 84.4 (26.6) 86.9 (21.0) .56 87.9 (25.0) 81.7 (25.6) .08
Body mass index 26.2 (6.5) 28.8 (7.7) .03 27.6 (7.1) 25.9 (6.4) .07
Ejection fraction 37 (23) 44 (22) .09 38 (23) 39 (22) .72
Creatinine, mg/dL 1.71 (1.69) 1.99 (1.50) .45 1.70 (1.20) 1.89 (2.06) .56
Bilirubin, mg/dL 0.8 (1.0) 1.1 (1.3) .34 0.7 (0.5) 1.1 (1.5) .11
Hemoglobin, g/dL 11.5 (2.6) 11.1 (2.4) .48 11.8 (2.5) 11.0 (2.6) .11
Hematocrit, % 34.2 (7.7) 33.6 (7.0) .70 35.2 (7.1) 32.6 (7.8) .08
White blood cells, 103/μL 9.9 (6.6) 9.5 (4.2) .78 10.1 (4.9) 9.4 (7.2) .55
Operative No. (%) No. (%) No. (%) No. (%)
Procedure
 Coronary artery bypass grafting 27 (17) 7 (16) .99 18 (17) 16 (17) .99
 Valve 69 (44) 29 (66) .01 48 (46) 50 (52) .40
 Aortic 45 (29) 13 (30) .99 28 (27) 30 (31) .53
 Ventricular-assist device 51 (33) 4 (9 .002 31 (30) 24 (25) .53
 Transplant 12 (8) 4 (9) .76 9 (9) 7 (7) .80
 Other 4 (3) 2 (5) .61 5 (5) 1 (1) .22
Hypothermic circulatory arrest 19 (12) 9 (21) .22 12 (11) 16 (17) .31
No. procedures .26 .31
 1 113 (72) 29 (66) 74 (71) 68 (71)
 2 39 (25) 15 (34) 30 (29) 24 (25)
 3 5 (3) 0 (0) 1 (1) 4 (4)
Return to operating room 13 (8) 0 (0) .08 8 (8) 5 (5) .57
Operative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Cross-clamp, min 128 (70) 172 (91) .006 132 (71) 149 (86) .22
Perfusion, min 158 (87) 205 (100) .003 162 (83) 176 (99) .31
Operative Median (IQR) Median (IQR) Median (IQR) Median (IQR)
Transfusion
 Red cell 6 (2–9) 5.5 (2–8) .86 5 (2–8) 6.5 (3–10) .04
 Plasma 4 (0–9) 4 (1–8) .76 4 (0–9) 4.5 (0–9) .36
 Platelet 2 (1–6) 3 (0–6) .86 2 (0–5) 4 (1–8) .05
 Cryoprecipitate 0 (0–1) 0 (0–2) .55 0 (0–1) 0 (0–2) .08
Postoperative day 21 No. (%) No. (%) No. (%) No. (%)
Vasopressor 20 (27) 9 (32) .63 18 (33) 11 (24) .38
Ventilator support 23 (15) 19 (43) < .001 25 (24) 17 (18) .30
Renal replacement therapy 19 (12) 11 (25) .05 20 (19) 10 (10) .11
Transfusion
 Red cell 29 (40) 12 (43) .82 25 (46) 16 (35) .31
 Plasma 18 (25) 4 (14) .30 14 (26) 8 (17) .35
 Platelet 13 (18) 4 (14) .77 8 (15) 9 (20) .60
 Cryoprecipitate 4 (6) 0 (0) .57 3 (6) 1 (2) .62
Postoperative pneumonia 23 (32) 37 (44) .14
Postoperative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Creatinine, mg/dL 1.63 (1.25) 2.09 (1.48) .15 1.80 (1.45) 1.73 (1.16) .79
Sodium, mmol/L 142 (6) 141 (5) .40 141 (6) 142 (6) .53
Chloride, mmol/L 107 (6) 105 (5) .16 106 (6) 107 (6) .66
Hemoglobin, g/dL 9.8 (3.0) 9.4 (1.3) .47 9.4 (1.2) 10.0 (3.8) .29
Hematocri, % 28.1 (4.5) 27.6 (4.0) .53 27.3 (4.0) 29.1 (4.7) .02
Bilirubin, mg/dL 1.6 (1.6) 2.6 (3.8) .20 2.0 (2.5) 2.0 (3.0) .95
Alanine transaminase, U/L 71 (66) 83 (109) .56 87 (101) 56 (42) .07
Alkaline phosphatase, U/L 146 (95) 134 (27) .74 160 (95) 116 (66) .11
White blood cells, 103/μL 11.2 (4.6) 14.3 (5.2) .006 12.2 (4.9) 12.2 (5.2) .99
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Data not available for all variables for all patients; for continuous variables with data missing, available data used from total no. patients for survival at discharge, mortality at discharge, survival at follow-up, mortality at follow-up: age, weight, body mass index (157, 44, 105, 96, respectively); ejection fraction (149, 42, 99, 92, respectively); preop creatinine, bilirubin, hemoglobin, hematocrit, white blood cells (73, 28, 55, 46, respectively); cross-clamp time (90, 32, 66, 56, respectively); perfusion time (151, 42, 99, 94, respectively); day 21 creatinine (58, 26, 49, 35, respectively); day 21 sodium, chloride, white blood cells (65, 27, 53, 39, respectively); day 21 hemoglobin (65, 26, 52, 39, respectively); day 21 hematocrit (19, 11, 19, 11, respectively); day 21 bilirubin (45, 27, 45, 27, respectively); day 21 alanine transaminase, alkaline phosphatase (44, 27, 44, 27, respectively).

eAPPENDIX 4.

Univariate Analysis of Factors Associated With Operative and Late Mortality for Patients With Intensive Care Unit Length of Stay ≥ 28 Daysa

At discharge At follow-up
Variables Survived (n = 1049) Deceased (n = 125) P value Survived (n = 754) Deceased (n = 420) P value
Preoperative No. (%) No. (%) No. (%) No. (%)
Sex, male 28 (54) 11 (39) .25 21 (54) 18 (44) .50
Race, White 45 (87) 26 (93) .48 34 (87) 37 (90) .73
Smoker 25 (48) 16 (57) .49 17 (44) 24 (59) .26
Diabetes mellitus 13 (25) 12 (43) .13 13 (33) 12 (29) .81
Renal failure 19 (37) 9 (32) .81 13 (33) 15 (37) .82
Dialysis 4 (8) 3 (11) .69 2 (5) 5 (12) .43
Hypertension 33 (64) 19 (68) .81 22 (56) 30 (73) .16
Cerebrovascular accident 5 (10) 5 (18) .31 5 (13) 5 (12) .99
Cerebrovascular disease 10 (19) 9 (32) .27 8 (21) 11 (27) .60
Infectious endocarditis 2 (4) 6 (21) .02 4 (10) 4 (10) .99
Chronic lung disease .01 .44
 Mild 5 (10) 4 (14) 5 (13) 4 (10)
 Moderate or severe 2 (4) 7 (25) 6 (15) 3 (7)
Peripheral vascular disease 3 (6) 4 (14) .23 3 (8) 4 (10) .99
Myocardial infarction 16 (31) 7 (25) .80 12 (31) 11 (27) .81
Congestive heart failure 34 (65) 14 (50) .23 22 (56) 26 (63) .65
Cardiogenic shock 13 (25) 2 (7) .07 10 (26) 5 (12) .16
Resuscitation 1 (2) 1 (4) .99 2 (5) 0 (0) .23
Preoperative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Age, y 62 (16) 63 (11) .72 59 (16) 65 (12) .05
Weight, kg 77.9 (28.0) 81.6 (17.8) .53 84.7 (26.4) 74.0 (22.3) .05
Body mass index 25.6 (6.6) 26.8 (5.5) .39 27.3 (6.5) 24.9 (5.9) .08
Ejection fraction 40 (23) 43 (23) .59 39 (24) 43 (21) .42
Creatinine, mg/dL 1.70 (1.16) 1.87 (1.23) .65 1.76 (1.13) 1.78 (1.24) .95
Bilirubin, mg/dL 0.6 (0.4) 1.0 (1.3) .22 0.6 (0.5) 0.9 (1.1) .33
Hemoglobin, g/dL 11.5 (2.0) 11.3 (2.3) .79 11.5 (2.4) 11.3 (1.8) .71
Hematocrit, % 34.1 (6.0) 33.8 (6.4) .84 34.3 (6.6) 33.7 (5.7) .74
White blood cells, 103/μL 8.6 (3.8) 9.2 (3.8) .62 8.8 (2.7) 8.9 (4.6) .92
Operative No. (%) No. (%) No. (%) No. (%)
Procedures
 Coronary artery bypass grafting 11 (21) 4 (14) .56 7 (18) 8 (20) .99
 Valve 20 (39) 19 (68) .02 18 (46) 21 (52) .66
 Aortic 10 (19) 7 (25) .58 8 (21) 9 (22) .99
 Ventricular-assist device 18 (37) 2 (7) .007 11 (28) 9 (22) .61
 Transplant 7 (14) 3 (11) .99 6 (15) 4 (10) .51
 Other 0 (0) 2 (7) .12 2 (5) 0 (0) .23
Hypothermic circulatory arrest 7 (13) 7 (25) .23 4 (10) 10 (24) .14
No. procedures .45 .34
 1 40 (77) 19 (68) 27 (69) 32 (78)
 2 11 (21) 9 (32) 12 (31) 8 (20)
 3 1 (2) 0 (0) 0 (0) 1 (2)
Return to operating room 7 (14) 0 (0) .09 5 (13) 2 (5) .26
Operative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Cross-clamp, min 126 (69) 184 (103) .03 146 (88) 154 (91) .76
Perfusion, min 148 (78) 208 (113) .01 170 (95) 166 (96) .84
Operative Median (IQR) Median (IQR) Median (IQR) Median (IQR)
Transfusion
 Red cell 7 (4–9) 5 (2–8.8) .20 5 (2–8) 8 (6–10) .003
 Plasma 4 (1–10) 4 (1–8) .33 4 (0–9) 4 (2–10) .23
 Platelet 3 (2–7) 3 (0–4) .25 2 (0–5) 3 (2–8) .17
 Cryoprecipitate 0 (0–2) 0 (0–1) .32 0 (0–1) 0 (0–2) .25
Postoperative No. (%) No. (%) No. (%) No. (%)
Vasopressor 3 (11) 4 (22) .42 3 (14) 4 (17) .99
Ventilator support 9 (17) 14 (50) .004 13 (33) 10 (24) .46
Renal replacement therapy 8 (15) 7 (25) .37 9 (23) 6 (15) .40
Transfusion
 Red cell 14 (54) 7 (39) .37 10 (48) 11 (48) .99
 Plasma 5 (19) 3 (17) .99 5 (24) 3 (13) .45
 Platelet 4 (15) 3 (17) .99 3 (14) 4 (17) .99
 Cryoprecipitate 1 (4) 0 (0) .99 0 (0) 1 (4) .99
Postoperative pneumonia 9 (45) 17 (53 .78
Postoperative Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Creatinine, mg/dL 1.66 (1.14) 1.88 (1.05) .58 1.73 (1.01) 1.83 (1.20) .79
Sodium, mmol/L 141 (4) 141 (4) .96 141 (4) 141 (4) .58
Chloride, mmol/L 104 (4) 102 (4) .30 103 (4) 103 (4) .69
Hemoglobin g/dL 9.5 (1.3) 9.6 (1.2) .88 9.6 (1.2) 9.5 (1.3) .84
Hematocrit, % 27.9 (3.4) 27.3 (3.1) .62 27.6 (3.4) 27.7 (3.1) .98
Bilirubin, mg/dL 0.8 (0.5) 3.3 (5.4) .15 2.9 (5.1) 0.8 (0.5) .18
Alanine transaminase, U/L 49 (37) 94 (122) .25 83 (116) 54 (35) .42
Alkaline phosphatase, U/L 131 (72) 133 (54) .92 139 (66) 122 (62) .44
White blood cells, 103/μL 11.6 (4.2) 11.9 (3.4) .79 11.8 (3.6) 11.7 (4.0) .91
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Data not available for all variables for all patients; for continuous variables with data missing, available data used from total no. patients for survival at discharge, mortality at discharge, survival at follow-up, mortality at follow-up: age, weight, body mass index (52, 28, 39, 41, respectively); ejection fraction (51, 28, 39, 40, respectively); preop creatinine, bilirubin, hemoglobin, hematocrit, white blood cells (26, 18, 21, 23, respectively); cross-clamp time (28, 19, 26, 21, respectively); perfusion time (51, 26, 36, 41, respectively); day 28 creatinine, sodium, chloride, hemoglobin, hematocrit, white blood cells (20, 17, 19, 18, respectively); day 28 bilirubin, alanine transaminase, alkaline phosphatase (14, 12, 14, 12, respectively).

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