536735
research-article2014
PENXXX10.1177/0148607114536735Journal of Parenteral and Enteral NutritionYu et al
Brief Communication
Impact of Preoperative Prealbumin on Outcomes After Cardiac Surgery Pey-Jen Yu, MD1; Hugh A. Cassiere, MD1; Sophia L. Dellis, MS1; Frank Manetta, MD1; Nina Kohn, MA2; and Alan R. Hartman, MD1
Journal of Parenteral and Enteral Nutrition Volume 39 Number 7 September 2015 870–874 © 2014 American Society for Parenteral and Enteral Nutrition DOI: 10.1177/0148607114536735 jpen.sagepub.com hosted at online.sagepub.com
Abstract Background: Preoperative malnutrition is increasingly prevalent in patients undergoing cardiac surgery. Although prealbumin is a widely used indicator of nutrition status, its use in the preoperative assessment of patients undergoing cardiac surgery is not well defined. The purpose of this study is to determine the impact of preoperative prealbumin levels on outcomes after cardiac surgery. Materials and Methods: Data were prospectively gathered from February 2013 to July 2013 on 69 patients undergoing cardiac surgery. Prealbumin levels were obtained within 24 hours of surgery. Patients were divided into 2 groups based on a prealbumin cutoff value of 20 mg/dL. Results: Of the 69 patients, 32 (46.4%) had a preoperative prealbumin ≤20 mg/dL. There was no correlation between prealbumin levels and body mass index (r = −0.13, P = .28). Likewise, there was no correlation between preoperative albumin and prealbumin levels (r = 0.09, P = .44). Nine of 32 (28.1%) patients with low preoperative prealbumin levels had postoperative infections compared with 2 of 37 (5.4%) patients with high prealbumin levels (P = .010). Patients with low prealbumin levels also had increased risk of postoperative intubation for >12 hours (P = .010). Conclusions: Patients undergoing cardiac surgery with preoperative prealbumin levels of ≤20 mg/dL have an increased risk for postoperative infections and the need for longer mechanical ventilation. If feasible, nutrition optimization of such patients may be considered prior to cardiac surgery. (JPEN J Parenter Enteral Nutr. 2015;39:870-874)
Keywords enteral nutrition; nutrition; nutrition assessment; cardiac disease; research and diseases
Clinical Relevancy Statement With the increasing acuity of patients undergoing cardiac surgery, the identification of modifiable preoperative risk factors is important to help decrease postoperative complications. This study represents the first to identify low preoperative prealbumin levels as a risk factor for postoperative infectious complication as well as need for prolonged mechanical ventilation. These findings are clinically relevant as they suggest that optimization of preoperative prealbumin levels may be a potential intervention to decrease postoperative complications.
Introduction Preoperative malnutrition occurs in 10%–25% of patients undergoing cardiac surgery and is associated with increased morbidity and mortality and a poorer quality of life after cardiac surgery.1-6 Identification of patients with malnutrition awaiting cardiac surgery is, therefore, not only important for operative risk stratification but also may identify patients who may benefit from nutrition optimization prior to surgery. Prior studies on the nutrition status of patients undergoing cardiac surgery have looked at serum albumin concentration as the objective measure of malnutrition.1,5,7 Serum albumin, however, has a long half-life, thus making it insensitive to recent changes in nutrition. Its concentration is also affected by hydration
status and renal function, both of which can be variable in patients awaiting cardiac surgery. In contrast, prealbumin has a relatively short half-life and is not affected by hydration status, making it a more accurate indicator of nutrition status, especially in patients with cardiac pathology. Its use in the assessment of malnutrition in hospitalized patients has been validated.8 Prealbumin has been shown to be predictive of morbidity and mortality in patients undergoing cytoreductive surgery for ovarian cancer,9 Acute Physiology and Chronic Health Evaluation II (APACHE II) score and mortality in critically ill nonsurgical patients,10 long-term mortality in hemodialysis patients,11 mortality in burn patients,12 infectious complications after gastric surgery,13 and postsurgical outcomes after pneumonectomy.14 Although validated in other From the 1North Shore University Hospital, Manhasset, New York, and 2 The Feinstein Institute for Medical Research, Manhasset, New York. Financial disclosure: None declared. Received for publication March 17, 2014; accepted for publication April 29, 2014. This article originally appeared online on June 4, 2014. Corresponding Author: Pey-Jen Yu, MD, Department of Cardiovascular and Thoracic Surgery, North Shore University Hospital, 300 Community Dr, 1DSU, Manhasset, NY 11030, USA. Email: [email protected]
Downloaded from pen.sagepub.com at CAMBRIDGE UNIV MEDICAL LIBRAR on August 22, 2015
Yu et al
871
Table 1. Patient Characteristics and Preoperative Prealbumin. Preoperative Prealbumin Characteristic Male sex Urgent status Chronic obstructive pulmonary disease Coronary artery bypass Diabetes mellitus Congestive heart failure Peripheral vascular disease Body mass index >30 kg/m2 Serum albumin, g/dL Creatinine, mg/dL Age Reoperation Ejection fraction, %
≤20 mg/dL (n = 32)
>20 mg/dL (n = 37)
22 (68.7) 15 (46.9) 4 (12.5) 16 (50.0) 10 (31.2) 11 (34.3) 3 (9.4) 11 (34.4) 4.1 (3.6–4.3) 1.0 (0.9–1.3) 68.5 (62.0–81.5) 3 (9.4) 55 (50–60)
29 (78.4) 11 (29.7) 4 (10.8) 22 (59.4) 14 (37.8) 7 (18.9) 6 (16.2) 8 (21.6) 4.1 (3.8–4.3) 1.1 (1.0–1.2) 69.0 (61.0–78.0) 3 (8.1) 55 (50–60)
P Value .364 .143 1.000 .431 .567 .145 .489 .237 .672 .474 .481 1.000 .903
Results are number (%) or median (interquartile range).
surgical and nonsurgical fields, the use of prealbumin in the preoperative assessment of patients undergoing cardiac surgery is not well defined. The purpose of this study is to identify the use of preoperative prealbumin as a marker for outcomes after cardiac surgery.
Methods This study was conducted with the approval of the North Shore–LIJ Health System Institutional Review Board with specific waiver of the need for individual patient consent. This is an observational study with prospectively collected data. Since prealbumin is synthesized by the liver, patients with preoperative hepatic dysfunction were excluded from the study. From February to July 2013, a total of 69 patients undergoing cardiac surgery without liver dysfunction had prealbumin levels drawn within 24 hours prior to surgery. In addition to preoperative prealbumin levels, data were collected on patient demographics, preoperative risk factors (diabetes, renal insufficiency, dialysis dependence, chronic lung disease, hypertension, liver dysfunction, congestive heart failure, prior cardiac surgery), preoperative medications, left ventricular ejection fraction, use of an intra-aortic balloon pump, operative variables (temperature on bypass, cardiopulmonary bypass time), transfusion requirements, and perioperative glucose control. End points include infectious and noninfectious postoperative complications, length of intubation, total hours in the intensive care unit (ICU), and length of hospital stay. Patients were categorized with having a postoperative infectious complication if they completed a postoperative course of antibiotics for clinical evidence of infection with or without positive cultures. Definitions used for the preoperative risk factors and perioperative complications were those used by the New York State Cardiac Surgery Reporting System.
Association between categorical variables and prealbumin levels (≤20 mg/dL, >20 mg/dL) and the presence of postoperative infection were examined using the χ2 test or Fisher exact test, as appropriate. The association between continuous variables and prealbumin levels and the presence of postoperative infection were examined using the Mann-Whitney test. The correlation between preoperative prealbumin to body mass index and preoperative albumin levels was examined by calculating the Spearman correlation coefficient. Data were managed and analyzed using SAS version 9.3 (SAS Institute, Cary, NC). All statistical tests were 2-sided with P < .05 considered statistically significant.
Results Of the 69 patients, 32 (46.4%) had a prealbumin level ≤20 mg/ dL. Preoperative demographics, risk factors, and operative procedure did not differ between the patients when grouped by prealbumin levels (Table 1). In particular, there was no difference in age, history of chronic obstructive pulmonary disease, diabetes mellitus, and incidence of coronary artery bypass surgery between the 2 groups. The mean ± SD serum albumin level of the cohort was 4.0 ± 0.5 g/dL. Twenty-seven patients (40.3%) had serum albumin levels 30 kg/m2 Serum albumin, g/dL Received pRBC transfusion Age, y Cardiopulmonary bypass time, min Postoperative day 1 glucose, mg/dL Postoperative day 2 glucose, mg/dL
6 (54.5) 7 (63.6) 4 (36.4) 4 (36.4) 4 (36.4) 0 (0.0) 5 (45.4) 0 (0.0) 5 (45.4) 3.9 (3.6–4.3) 9 (81.8) 80 (71–82) 159 (94–226) 125 (120–130) 140 (123–179)
45 (77.6) 19 (32.7) 4 (6.9) 34 (58.6) 20 (34.5) 6 (10.3) 13 (22.4) 9 (15.5) 14 (21.1) 4.1 (3.8–4.3) 26 (44.8) 67 (58–78) 122 (95–151) 125 (114–132) 128 (112–146)
P Value .139 .087 .018 .202 1.000 .579 .139 .336 .161 .470 .024 .007 .238 .441 .129
Results are number (%) or median (interquartile range). pRBC, packed red blood cell.
Univariate analysis of preoperative prealbumin levels and postoperative outcomes showed that low prealbumin levels were associated with increased incidence of postoperative infection and increased postoperative intubation time (Table 2). Of patients with a preoperative prealbumin level ≤20 mg/dL, 28% (9 patients) had postoperative infections compared with 5% (2 patients) of patients with a preoperative prealbumin level >20 mg/dL (P = .01). Patients with a preoperative prealbumin level ≤20 mg/dL were also more likely to be intubated for longer than 12 hours after surgery compared with patients with a preoperative prealbumin level >20 mg/dL (P = .01). There was no difference in noninfectious postoperative complications, length of ICU stay, and length of hospital stay between the 2 groups when separated by preoperative prealbumin levels (Table 2). Aside from preoperative prealbumin, other risk factors for postoperative infectious complications include the presence of chronic obstructive pulmonary disease (P = .018), increasing age (P = .007), and the need for red blood cell transfusions
(P = .024) (Table 3). Neither preoperative serum albumin nor body mass index was associated with postoperative infections (Table 3).
Discussion Since preoperative malnutrition has been shown to increase postoperative morbidity and mortality in patients undergoing cardiac surgery, proper preoperative diagnosis of malnutrition will identify patients who may benefit from nutrition optimization prior to surgery.5 Frequently used screening tools such as the Malnutrition Universal Screening Tool (MUST), the Cardiac Surgery-Specific MUST (CSSM), and the Short Nutritional Assessment Questionnaire have marginal accuracy in identifying undernutrition in patients undergoing cardiac surgery.15 The most commonly used and well-studied objective measures of malnutrition in cardiac surgery patients are serum albumin and low body mass index. Engelman et al1 found that body mass index
research-article2014
PENXXX10.1177/0148607114536735Journal of Parenteral and Enteral NutritionYu et al
Brief Communication
Impact of Preoperative Prealbumin on Outcomes After Cardiac Surgery Pey-Jen Yu, MD1; Hugh A. Cassiere, MD1; Sophia L. Dellis, MS1; Frank Manetta, MD1; Nina Kohn, MA2; and Alan R. Hartman, MD1
Journal of Parenteral and Enteral Nutrition Volume 39 Number 7 September 2015 870–874 © 2014 American Society for Parenteral and Enteral Nutrition DOI: 10.1177/0148607114536735 jpen.sagepub.com hosted at online.sagepub.com
Abstract Background: Preoperative malnutrition is increasingly prevalent in patients undergoing cardiac surgery. Although prealbumin is a widely used indicator of nutrition status, its use in the preoperative assessment of patients undergoing cardiac surgery is not well defined. The purpose of this study is to determine the impact of preoperative prealbumin levels on outcomes after cardiac surgery. Materials and Methods: Data were prospectively gathered from February 2013 to July 2013 on 69 patients undergoing cardiac surgery. Prealbumin levels were obtained within 24 hours of surgery. Patients were divided into 2 groups based on a prealbumin cutoff value of 20 mg/dL. Results: Of the 69 patients, 32 (46.4%) had a preoperative prealbumin ≤20 mg/dL. There was no correlation between prealbumin levels and body mass index (r = −0.13, P = .28). Likewise, there was no correlation between preoperative albumin and prealbumin levels (r = 0.09, P = .44). Nine of 32 (28.1%) patients with low preoperative prealbumin levels had postoperative infections compared with 2 of 37 (5.4%) patients with high prealbumin levels (P = .010). Patients with low prealbumin levels also had increased risk of postoperative intubation for >12 hours (P = .010). Conclusions: Patients undergoing cardiac surgery with preoperative prealbumin levels of ≤20 mg/dL have an increased risk for postoperative infections and the need for longer mechanical ventilation. If feasible, nutrition optimization of such patients may be considered prior to cardiac surgery. (JPEN J Parenter Enteral Nutr. 2015;39:870-874)
Keywords enteral nutrition; nutrition; nutrition assessment; cardiac disease; research and diseases
Clinical Relevancy Statement With the increasing acuity of patients undergoing cardiac surgery, the identification of modifiable preoperative risk factors is important to help decrease postoperative complications. This study represents the first to identify low preoperative prealbumin levels as a risk factor for postoperative infectious complication as well as need for prolonged mechanical ventilation. These findings are clinically relevant as they suggest that optimization of preoperative prealbumin levels may be a potential intervention to decrease postoperative complications.
Introduction Preoperative malnutrition occurs in 10%–25% of patients undergoing cardiac surgery and is associated with increased morbidity and mortality and a poorer quality of life after cardiac surgery.1-6 Identification of patients with malnutrition awaiting cardiac surgery is, therefore, not only important for operative risk stratification but also may identify patients who may benefit from nutrition optimization prior to surgery. Prior studies on the nutrition status of patients undergoing cardiac surgery have looked at serum albumin concentration as the objective measure of malnutrition.1,5,7 Serum albumin, however, has a long half-life, thus making it insensitive to recent changes in nutrition. Its concentration is also affected by hydration
status and renal function, both of which can be variable in patients awaiting cardiac surgery. In contrast, prealbumin has a relatively short half-life and is not affected by hydration status, making it a more accurate indicator of nutrition status, especially in patients with cardiac pathology. Its use in the assessment of malnutrition in hospitalized patients has been validated.8 Prealbumin has been shown to be predictive of morbidity and mortality in patients undergoing cytoreductive surgery for ovarian cancer,9 Acute Physiology and Chronic Health Evaluation II (APACHE II) score and mortality in critically ill nonsurgical patients,10 long-term mortality in hemodialysis patients,11 mortality in burn patients,12 infectious complications after gastric surgery,13 and postsurgical outcomes after pneumonectomy.14 Although validated in other From the 1North Shore University Hospital, Manhasset, New York, and 2 The Feinstein Institute for Medical Research, Manhasset, New York. Financial disclosure: None declared. Received for publication March 17, 2014; accepted for publication April 29, 2014. This article originally appeared online on June 4, 2014. Corresponding Author: Pey-Jen Yu, MD, Department of Cardiovascular and Thoracic Surgery, North Shore University Hospital, 300 Community Dr, 1DSU, Manhasset, NY 11030, USA. Email: [email protected]
Downloaded from pen.sagepub.com at CAMBRIDGE UNIV MEDICAL LIBRAR on August 22, 2015
Yu et al
871
Table 1. Patient Characteristics and Preoperative Prealbumin. Preoperative Prealbumin Characteristic Male sex Urgent status Chronic obstructive pulmonary disease Coronary artery bypass Diabetes mellitus Congestive heart failure Peripheral vascular disease Body mass index >30 kg/m2 Serum albumin, g/dL Creatinine, mg/dL Age Reoperation Ejection fraction, %
≤20 mg/dL (n = 32)
>20 mg/dL (n = 37)
22 (68.7) 15 (46.9) 4 (12.5) 16 (50.0) 10 (31.2) 11 (34.3) 3 (9.4) 11 (34.4) 4.1 (3.6–4.3) 1.0 (0.9–1.3) 68.5 (62.0–81.5) 3 (9.4) 55 (50–60)
29 (78.4) 11 (29.7) 4 (10.8) 22 (59.4) 14 (37.8) 7 (18.9) 6 (16.2) 8 (21.6) 4.1 (3.8–4.3) 1.1 (1.0–1.2) 69.0 (61.0–78.0) 3 (8.1) 55 (50–60)
P Value .364 .143 1.000 .431 .567 .145 .489 .237 .672 .474 .481 1.000 .903
Results are number (%) or median (interquartile range).
surgical and nonsurgical fields, the use of prealbumin in the preoperative assessment of patients undergoing cardiac surgery is not well defined. The purpose of this study is to identify the use of preoperative prealbumin as a marker for outcomes after cardiac surgery.
Methods This study was conducted with the approval of the North Shore–LIJ Health System Institutional Review Board with specific waiver of the need for individual patient consent. This is an observational study with prospectively collected data. Since prealbumin is synthesized by the liver, patients with preoperative hepatic dysfunction were excluded from the study. From February to July 2013, a total of 69 patients undergoing cardiac surgery without liver dysfunction had prealbumin levels drawn within 24 hours prior to surgery. In addition to preoperative prealbumin levels, data were collected on patient demographics, preoperative risk factors (diabetes, renal insufficiency, dialysis dependence, chronic lung disease, hypertension, liver dysfunction, congestive heart failure, prior cardiac surgery), preoperative medications, left ventricular ejection fraction, use of an intra-aortic balloon pump, operative variables (temperature on bypass, cardiopulmonary bypass time), transfusion requirements, and perioperative glucose control. End points include infectious and noninfectious postoperative complications, length of intubation, total hours in the intensive care unit (ICU), and length of hospital stay. Patients were categorized with having a postoperative infectious complication if they completed a postoperative course of antibiotics for clinical evidence of infection with or without positive cultures. Definitions used for the preoperative risk factors and perioperative complications were those used by the New York State Cardiac Surgery Reporting System.
Association between categorical variables and prealbumin levels (≤20 mg/dL, >20 mg/dL) and the presence of postoperative infection were examined using the χ2 test or Fisher exact test, as appropriate. The association between continuous variables and prealbumin levels and the presence of postoperative infection were examined using the Mann-Whitney test. The correlation between preoperative prealbumin to body mass index and preoperative albumin levels was examined by calculating the Spearman correlation coefficient. Data were managed and analyzed using SAS version 9.3 (SAS Institute, Cary, NC). All statistical tests were 2-sided with P < .05 considered statistically significant.
Results Of the 69 patients, 32 (46.4%) had a prealbumin level ≤20 mg/ dL. Preoperative demographics, risk factors, and operative procedure did not differ between the patients when grouped by prealbumin levels (Table 1). In particular, there was no difference in age, history of chronic obstructive pulmonary disease, diabetes mellitus, and incidence of coronary artery bypass surgery between the 2 groups. The mean ± SD serum albumin level of the cohort was 4.0 ± 0.5 g/dL. Twenty-seven patients (40.3%) had serum albumin levels 30 kg/m2 Serum albumin, g/dL Received pRBC transfusion Age, y Cardiopulmonary bypass time, min Postoperative day 1 glucose, mg/dL Postoperative day 2 glucose, mg/dL
6 (54.5) 7 (63.6) 4 (36.4) 4 (36.4) 4 (36.4) 0 (0.0) 5 (45.4) 0 (0.0) 5 (45.4) 3.9 (3.6–4.3) 9 (81.8) 80 (71–82) 159 (94–226) 125 (120–130) 140 (123–179)
45 (77.6) 19 (32.7) 4 (6.9) 34 (58.6) 20 (34.5) 6 (10.3) 13 (22.4) 9 (15.5) 14 (21.1) 4.1 (3.8–4.3) 26 (44.8) 67 (58–78) 122 (95–151) 125 (114–132) 128 (112–146)
P Value .139 .087 .018 .202 1.000 .579 .139 .336 .161 .470 .024 .007 .238 .441 .129
Results are number (%) or median (interquartile range). pRBC, packed red blood cell.
Univariate analysis of preoperative prealbumin levels and postoperative outcomes showed that low prealbumin levels were associated with increased incidence of postoperative infection and increased postoperative intubation time (Table 2). Of patients with a preoperative prealbumin level ≤20 mg/dL, 28% (9 patients) had postoperative infections compared with 5% (2 patients) of patients with a preoperative prealbumin level >20 mg/dL (P = .01). Patients with a preoperative prealbumin level ≤20 mg/dL were also more likely to be intubated for longer than 12 hours after surgery compared with patients with a preoperative prealbumin level >20 mg/dL (P = .01). There was no difference in noninfectious postoperative complications, length of ICU stay, and length of hospital stay between the 2 groups when separated by preoperative prealbumin levels (Table 2). Aside from preoperative prealbumin, other risk factors for postoperative infectious complications include the presence of chronic obstructive pulmonary disease (P = .018), increasing age (P = .007), and the need for red blood cell transfusions
(P = .024) (Table 3). Neither preoperative serum albumin nor body mass index was associated with postoperative infections (Table 3).
Discussion Since preoperative malnutrition has been shown to increase postoperative morbidity and mortality in patients undergoing cardiac surgery, proper preoperative diagnosis of malnutrition will identify patients who may benefit from nutrition optimization prior to surgery.5 Frequently used screening tools such as the Malnutrition Universal Screening Tool (MUST), the Cardiac Surgery-Specific MUST (CSSM), and the Short Nutritional Assessment Questionnaire have marginal accuracy in identifying undernutrition in patients undergoing cardiac surgery.15 The most commonly used and well-studied objective measures of malnutrition in cardiac surgery patients are serum albumin and low body mass index. Engelman et al1 found that body mass index
