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Does the Geriatric Nutritional Risk Index Play a Predictive Role in Postoperative Atrial Fibrillation and Outcomes in Cardiac Surgery?

  • Liuyang Wu
    Affiliations
    The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China

    Department of Cardiovascular Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhu, China
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  • Qiqi Yan
    Affiliations
    The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China

    Department of Cardiovascular Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhu, China
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  • Haohui Mai
    Affiliations
    Department of Cardiovascular Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhu, China
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  • Jikai Song
    Affiliations
    Department of Cardiovascular Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhu, China
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  • Lifang Ye
    Affiliations
    Department of Cardiovascular Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhu, China
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  • Xiaoru Che
    Affiliations
    Department of Cardiovascular Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhu, China
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  • Lihong Wang
    Correspondence
    Address correspondence to Lihong Wang, Department of Cardiovascular Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, No. 158, Shangtang Road, Gongshu District, Hangzhou, China.
    Affiliations
    Department of Cardiovascular Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhu, China
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Open AccessPublished:September 30, 2022DOI:https://doi.org/10.1053/j.jvca.2022.09.097

      Objectives

      Malnutrition is associated with adverse surgical outcomes. The Geriatric Nutritional Risk Index, a nutritional screening tool, could be a predictor of postoperative atrial fibrillation and outcomes in cardiac surgery.

      Design

      The authors enrolled 292 patients who underwent cardiac surgery and showed postoperative atrial fibrillation during hospitalization, and assessed mortality and readmission during a 90-day follow-up period.

      Setting

      A large academic hospital in China.

      Participants

      Participants were divided into low-risk (Geriatric Nutritional Risk Index <98) and no-risk malnutrition groups (Geriatric Nutritional Risk Index ≥98).

      Interventions

      Univariate and multivariate logistic regression analyses were used to validate the role of the Geriatric Nutritional Risk Index in predicting postoperative atrial fibrillation. Kaplan–Meier analysis was used to examine the effect of Geriatric Nutritional Risk Index scores on mortality and readmission after cardiac surgery.

      Measurements and Main Results

      A total of 136 patients were in the low-risk malnutrition group. Postoperative atrial fibrillation was more common in the low-risk group (63.2% v 28.8%, p < 0.001). Duration of intensive care unit stays and hospitalization were significantly longer than in the no-risk group (44 [43] v 39 [47] hours, p < 0.001; 18 [7] v 15 [6] days, p < 0.001). Multivariate analysis showed that Geriatric Nutritional Risk Index, age, and NYHA class independently predicted postoperative atrial fibrillation. Kaplan–Meier analysis showed that 90-day all-cause readmission, but not 90-day all-cause mortality, was different between groups based on the Geriatric Nutritional Risk Index (log-rank p < 0.001, log-rank p = 0.09).

      Conclusions

      The easily accessible Geriatric Nutritional Risk Index used for nutritional assessment before cardiac surgery has a predictive role in postoperative atrial fibrillation, and is related to short-term readmission.

      Key Words

      POSTOPERATIVE ATRIAL fibrillation (POAF) is the most common complication after cardiac surgery. The overall incidence of POAF is about 20%-to-65%,
      • Rezaei Y
      • Peighambari MM
      • Naghshbandi S
      • et al.
      Postoperative atrial fibrillation following cardiac surgery: From pathogenesis to potential therapies.
      ,
      • Kadado AJ
      • Freeman J
      • Akar JG.
      Postoperative atrial fibrillation and Maslow's hammer.
      which varies according to the type of cardiac surgery, definition of atrial fibrillation, and duration of monitoring. Due to atrial fibrillation, the heart loses its normal rhythm, resulting in ventricular underfilling and hemodynamic disturbances, thus increasing the risks of thrombosis and embolism, heart failure, and myocardial ischemia.
      • Echahidi N
      • Pibarot P
      • O'Hara G
      • et al.
      Mechanisms, prevention, and treatment of atrial fibrillation after cardiac surgery.
      Accordingly, POAF can cause increased risks of stroke and death, average hospital stay, and hospital fees.
      • Maisel WH
      • Rawn JD
      • Stevenson WG.
      Atrial fibrillation after cardiac surgery.
      ,
      • Aranki SF
      • Shaw DP
      • Adams DH
      • et al.
      Predictors of atrial fibrillation after coronary artery surgery. Current trends and impact on hospital resources.
      Although some attempts have been made to reduce the incidence of POAF, including pharmacologic prevention and operative changes, the incidence of POAF remains around 30%.
      • Goldman SM.
      Commentary: Postoperative atrial fibrillation: “No magic bullet”.
      To reduce the incidence of POAF, a sound preoperative evaluation to identify risk factors to predict the occurrence of POAF is necessary.
      Preoperative malnutrition is also prevalent in hospitalized patients; nearly a third of inpatients have malnutrition or are at risk of malnutrition at admission.
      • Gomes F
      • Schuetz P
      • Bounoure L
      • et al.
      ESPEN guidelines on nutritional support for polymorbid internal medicine patients.
      ,
      • Schuetz P
      • Seres D
      • Lobo DN
      • et al.
      Management of disease-related malnutrition for patients being treated in hospital.
      Chronic malnutrition and high risk of malnutrition have been associated with prolonged intensive care unit (ICU) and hospital stays, adverse postoperative complications, and mortality after cardiac surgery.
      • Ross F
      • Latham G
      • Joffe D
      • et al.
      Preoperative malnutrition is associated with increased mortality and adverse outcomes after paediatric cardiac surgery.
      • Hill A
      • Arora RC
      • Engelman DT
      • et al.
      Preoperative treatment of malnutrition and sarcopenia in cardiac surgery: New frontiers.
      • Chermesh I
      • Hajos J
      • Mashiach T
      • et al.
      Malnutrition in cardiac surgery: Food for thought.
      • Yu PJ
      • Cassiere HA
      • Dellis SL
      • et al.
      Impact of preoperative prealbumin on outcomes after cardiac surgery.
      Several routine nutritional screening tools are available in clinical practice, ranging from simple measurements, such as weight loss and body mass index, to complex tools, such as the Malnutrition Universal Screening Tool, Nutritional Risk Screening 2002, and the Short Nutritional Assessment Questionnaire.
      • Lomivorotov VV
      • Efremov SM
      • Boboshko VA
      • et al.
      Evaluation of nutritional screening tools for patients scheduled for cardiac surgery.
      • Florath I
      • Albert AA
      • Rosendahl UP
      • et al.
      Body mass index: A risk factor for 30-day or six-month mortality in patients undergoing aortic valve replacement?.
      • Lopez-Delgado JC
      • Muñoz-Del Rio G
      • Flordelís-Lasierra JL
      • et al.
      Nutrition in adult cardiac surgery: Preoperative evaluation, management in the postoperative period, and clinical implications for outcomes.
      However, these nutritional screening tools were not originally developed specifically for cardiac surgery patients and have not demonstrated good sensitivity and specificity.
      Since the concept of the Geriatric Nutritional Risk Index (GNRI) was first introduced by Olivier Bouillanne and his colleagues,
      • Bouillanne O
      • Morineau G
      • Dupont C
      • et al.
      Geriatric Nutritional Risk Index: A new index for evaluating at-risk elderly medical patients.
      GNRI has proven its reliability and stability as a simple and easily accessible nutritional assessment tool for elderly patients with heart failure, hemodialysis, or malignancies.
      • Yoshida M
      • Nakashima A
      • Doi S
      • et al.
      Lower Geriatric Nutritional Risk Index (GNRI) is associated with higher risk of fractures in patients undergoing hemodialysis.
      • Li H
      • Cen K
      • Sun W
      • et al.
      Prognostic value of geriatric nutritional risk index in elderly patients with heart failure: A meta-analysis.
      • Yan D
      • Shen Z
      • Zhang S
      • et al.
      Prognostic values of geriatric nutritional risk index (GNRI) and prognostic nutritional index (PNI) in elderly patients with diffuse large B-cell lymphoma.
      • Yamana I
      • Takeno S
      • Shimaoka H
      • et al.
      Geriatric Nutritional Risk Index as a prognostic factor in patients with esophageal squamous cell carcinoma -retrospective cohort study.
      However, limited studies have investigated the independently predictive value of the GNRI in patients who have undergone cardiac surgery.
      • Izawa KP
      • Watanabe S.
      Relation of nutritional status to physiological outcomes after cardiac surgery in elderly patients with diabetes mellitus: A preliminary study.
      ,
      • Unosawa S
      • Taoka M
      • Osaka S
      • et al.
      Is malnutrition associated with postoperative complications after cardiac surgery?.
      In this study, the authors aimed to evaluate the utility of the GNRI as a preoperative nutritional status assessment before adult cardiac surgery. The authors hypothesized that patients undergoing cardiac surgery with a low-score GNRI would have a higher incidence of POAF and a worse clinical prognosis than those with a high-score GNRI.

      Methods

      Study Population and Definition

      This was a cohort study conducted between January and December 2020. It was approved by the Ethics Committee, and informed consent was waived due to the retrospective nature of the study. The authors enrolled patients older than 18, and who had undergone elective cardiac surgery, including isolated coronary artery bypass grafting (CABG), isolated valve surgery (aortic, mitral, tricuspid), combined surgery, or CABG/valve surgery combined with other surgeries (eg, lobectomy, atrial septal repair, or myxoma). Exclusion criteria were (1) history of atrial fibrillation; (2) terminal illness (life expectancy of no more than 3 months); (3) history of emergency surgery; and (4) death during hospitalization. The authors first included 455 patients and then excluded 50 patients with emergency surgery, 59 with previous atrial fibrillation, 23 younger than 18, and 31 with malignancy. Finally, 292 patients participated in the study.
      The hospital's computerized medical record system collected the demographic characteristics, preoperative examination results, procedure information, and clinical outcomes for the 292 eligible patients. The follow-up period was 90 days after discharge from the hospital, via outpatient records and telephone, with death or readmission within 90 days considered as the endpoint of follow-up.
      POAF was determined based on the documentation of continuous telemetry, 12-lead electrocardiogram, or Holter monitoring of atrial fibrillation (AF) episodes (duration ≥30 seconds) during hospitalization.

      Evaluation of the Nutritional Status

      The preoperative nutritional status was evaluated using GNRI within 48 hours of admission. GNRI was calculated using the following formula: GNRI = [1.489  ×  albumin (g/dL)] + [41.7  ×  body weight (kg)/ideal body weight (kg)]. The ideal body weight (kg) for men was calculated as: height (cm) − 100 − [(height (cm) − 150)/4]. For women it was calculated as: height (cm) − 100 − [(height (cm) − 150)/2.5].
      • Bouillanne O
      • Morineau G
      • Dupont C
      • et al.
      Geriatric Nutritional Risk Index: A new index for evaluating at-risk elderly medical patients.
      According to previously described cutoffs for GNRI,
      • Bouillanne O
      • Morineau G
      • Dupont C
      • et al.
      Geriatric Nutritional Risk Index: A new index for evaluating at-risk elderly medical patients.
      ,
      • Lee K
      • Ahn JM
      • Kang DY
      • et al.
      Nutritional status and risk of all-cause mortality in patients undergoing transcatheter aortic valve replacement assessment using the geriatric nutritional risk index and the controlling nutritional status score.
      • Seoudy H
      • Al-Kassou B
      • Shamekhi J
      • et al.
      Frailty in patients undergoing transcatheter aortic valve replacement: Prognostic value of the Geriatric Nutritional Risk Index.
      • Katayama T
      • Hioki H
      • Kyono H
      • Watanabe Y
      • et al.
      Predictive value of the geriatric nutritional risk index in percutaneous coronary intervention with rotational atherectomy.
      the patients were stratified into 2 groups according to malnutrition risk as: no-risk (GNRI ≥98) and low-risk (GNRI <98) groups.

      Statistical Analysis

      Normally distributed continuous variables were presented as means and standard deviations, and non-normally distributed data were presented as medians with interquartile ranges (IQR). Normally distributed data was analyzed using the Kolmogorov–Smirnov test. The Student's t test was used to analyze normally distributed data, and the Mann–Whitney U test was used to analyze non-normally distributed data. Categorical data were described as frequencies (percentages) and analyzed using the Pearson's Chi-squared test. The potential risk factors of POAF initially were identified by univariate logistic regression analysis. To validate that these factors had independent effects, significant univariate correlates were then added to the multivariate logistic regression. The 90-day all-cause mortality and 90-day all-cause readmission were calculated using the Kaplan–Meier analysis with the log-rank test over time. All statistical analyses were performed using SPSS software (version 26.0; SPSS Inc., Chicago, IL). Statistical significance was defined as a two-sided p value of < 0.05.

      Results

      Baseline Characteristics of the 2 Groups of Patients

      Table 1 summarizes the patients' baseline characteristics. The 292 participants were separated into 2 groups according to GNRI: no-risk (GNRI ≥98, n = 156) and low-risk (GNRI < 98, n = 136). The mean age was 59.77 ± 13.03 years, and 64% of the participants were men. Patients in the low-risk group were older (p < 0.001) and had lower body mass indexes (p < 0.001) than those in the no-risk group. The 2 groups had different NYHA classes (I-II: 37.5% v 60.9%, III-IV: 62.5% v 39.1%, respectively).
      Table 1Baseline Characteristics of Patients
      VariableTotal (N = 292)GNRIp Value
      Low Risk <98 (n = 136)No Risk ≥98 (n = 156)
      Age (y)59.77 ± 13.0362.21 ± 12.7057.29 ± 12.85<0.001
      Male, n (%)187 (64.0)92 (67.6)95 (60.9)0.230
      BMI (kg/m2)23.33 ± 2.9821.37 ± 2.0725.04 ± 2.57<0.001
      Smoking, n (%)59 (20.2)28 (20.6)31 (19.9)0.880
      Comorbidities, n (%)
       Hypertension143 (49.0)62 (45.6)81 (51.9)0.280
       Diabetes mellitus39 (13.4)20 (14.7)19 (12.2)0.530
       Heart failure79 (27.1)43 (31.6)36 (23.1)0.100
       COPD3 (1.0)2 (1.5)1 (0.6)0.910
      Drugs, n (%)
       ACEI/ARB69 (23.6)34 (25.0)35 (22.4)0.610
       Calcium channel blocker55 (18.8)22 (16.2)33 (21.2)0.280
       Beta-blocker46 (15.8)24 (18.2)22 (14.1)0.410
       Diuretic77 (26.3)40 (29.4)37 (23.7)0.270
       Statin30 (10.3)14 (10.3)16 (10.3)0.990
      GNRI98.77 ± 8.2991.88 ± 4.69104.78 ± 5.65<0.001
      Previous cardiac surgery, n (%)40 (13.7)19 (14.0)21 (13.5)0.900
      NYHA class, n (%)
       I-II146 (50.0)51 (37.5)95 (60.9)<0.001
       III-IV146 (50.0)85 (62.5)61 (39.1)<0.001
      Preoperative laboratory test
       Creatinine (umol/L)77.85 (23.10)80.35 (24.50)76.95 (21.3)0.120
       eGFR (mL/min/1.73m2)90.78 ± 22.8788.66 ± 23.5292.64 ± 22.210.590
       Serum potassium (mmol/L)3.89 ± 0.413.98 ± 0.443.82 ± 0.370.020
       Serum sodium (mmol/L)140.95 ± 3.86140.32 ± 5.09141.50 ± 2.200.010
       Serum magnesium (mmol/L)0.88 ± 0.130.89 ± 0.160.88 ± 0.090.140
       White blood cell count (× 1012/L)6.14 ± 1.876.22 ± 2.216.07 ± 1.520.001
       Lymphocyte count (× 109/L)1.65 ± 0.591.52 ± 0.611.76 ± 0.560.001
       Red blood cell count (× 1012/L)4.32 ± 0.544.23 ± 0.544.41 ± 0.520.005
       Hemoglobin (g/L)130.58 ± 17.30127.23 ± 17.76133.49 ± 16.390.298
       Platelets count (× 109/L)195.02 ± 57.39184.96 ± 61.02203.79 ± 52.670.005
      Echocardiography
       LAD (mm)41.15 ± 7.4342.11 ± 8.0940.31 ± 6.730.041
       LVEF (%)62.00 (12.00)60.50 (12.00)63.00 (9.00)0.002
       LVIDd (mm)54.53 ± 9.6855.17 ± 10.5953.98 ± 8.810.302
       LVIDs (mm)36.84 ± 8.6337.95 ± 9.4235.88 ± 7.790.043
      Type of procedure, n (%)
       CABG58 (19.9)27 (19.9)31 (19.9)0.871
       Aortic valve procedure63 (21.6)25 (18.4)38 (24.4)0.216
       Mitral valve procedure60 (20.5)24 (17.6)36 (23.1)0.252
       Tricuspid valve procedure2 (1.0)1 (1.0)1 (1.0)1.000
       Double valve procedure43 (14.7)27 (19.9)16 (10.3)0.218
       CABG + Valve23 (7.9)11 (8.1)12 (7.7)0.900
       Aortic valve procedure + others
      Lobectomy, atrial septal repair, or myxoma operation.
      39 (13.4)18 (13.2)21 (13.5)0.955
       Mitral valve procedure + others4 (1.4)3 (2.2)1 (1.0)0.520
      CPB time (min)144.88 ± 56.40146.27 ± 48.93143.69 ± 62.250.696
      Cross-clamp time (min)96.50 (52.00)104.00 (59.00)93.00 (50.00)0.161
      Operation time (min)295.43 ± 72.86297.17 ± 60.64293.91 ± 82.220.698
      Abbreviations: ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin-receptor blocker; BMI, body mass index; CABG, coronary artery bypass surgery; COPD, chronic obstructive pulmonary disease; CPB, cardiopulmonary bypass; eGFR, estimated glomerular filtration rate; GNRI, Geriatric Nutritional Risk Index; LAD, left atrial diameter; LVEF, left ventricular ejection fraction; LVIDd, left ventricular internal diameter diastolic; LVIDs, left ventricular internal diameter systolic.
      low asterisk Lobectomy, atrial septal repair, or myxoma operation.
      Patients in the low-risk group had higher levels of serum potassium, white blood cell count, left atrial diameter (LAD), and left ventricular internal diameter systolic than those in the no-risk group (p < 0.05). Patients in the low-risk group had lower serum sodium levels, lymphocyte count, red blood cell count, platelet count, lymphocyte and red blood cell counts, and left ventricular ejection fraction than those in the no-risk group (p < 0.05). However, the type of procedure, cardiopulmonary bypass time, aortic cross-clamp time, and surgery time were not different between the groups.

      POAF and Outcome

      As shown in Table 2, 131 patients developed POAF during hospitalization (overall incidence of approximately 40%), 86 (63.2%) in the low-risk group, and 45 (28.8%) in the no-risk group. The incidence of POAF was significantly different between the 2 GNRI groups (p < 0.001). Median (IQR) duration of ICU stays and hospitalization period were 44 hours (43) and 18 days (7), respectively, for participants in the low-risk group. This was significantly longer than those for participants in the no-risk group (p < 0.001).
      Table 2POAF and Outcome
      VariableTotal (N = 292)GNRIp Value
      Low Risk <98 (n = 136)No Risk ≥98(n = 156)
      POAF, n (%)131 (44.9)86 (63.2)45 (28.8)<0.001
      Duration of ICU stays (h)42.5 (45.0)44.0 (43.0)39.0 (47.0)<0.001
      Hospitalization period (d)16.0 (6.0)18.0 (7.0)15.0 (6.0)<0.001
      90-day all-cause mortality, n (%)3 (1.0)3 (1.0)0 (0)<0.001
      90-day all-cause readmission, n (%)40 (13.7)31 (22.8)9 (5.8)<0.001
      Infection, n (%)
      Incision infection7 (2.4)6 (4.4)1 (0)0.086
      Pneumonia8 (2.7)6 (4.4)2 (1.3)0.202
      Heart failure6 (2.1)4 (2.9)2 (1.3)0.560
      Pleural/pericardial effusion4 (1.4)3 (2.2)1 (0)0.520
      Acute kidney injury3 (1.0)3 (2.2)0 (0)0.200
      Bleeding5 (1.7)4 (2.9)1 (0)0.290
      Stroke7 (2.4)5 (3.7)2 (1.3)0.342
      Abbreviations: ICU, intensive care units; POAF, postoperative atrial fibrillation.
      The 90-day all-cause mortality was 1.0% (n = 3) in both groups. Causes of death included acute myocardial infarction (n = 1) and acute kidney injury (n = 2); all deaths occurred in the low-risk group. At the 90-day follow-up, about 14% of patients were readmitted for infections (incision infection/pneumonia), heart failure, pleural effusion/pericardial effusion that required drainage, acute kidney injury, bleeding, or stroke. The reasons for readmission were not statistically different between the 2 groups. However, the overall 90-day all-cause readmission was higher in the low-risk group than in the no-risk group (p < 0.001). Kaplan–Meier analysis showed that the 90-day all-cause readmission was significantly different between the groups based on GNRI; however, this was not true for the 90-day all-cause mortality (Figs. 1 and 2).
      Fig 1
      Fig 1Kaplan-Meier analysis for 90-day all-cause mortality. GNRI, Geriatric Nutritional Risk Index.
      Fig 2
      Fig 2Kaplan-Meier analysis for 90-day all-cause readmission; p > 0.05 was considered statistically significant. GNRI, Geriatric Nutritional Risk Index.

      Risk Factors of POAF

      The potential risk factors of POAF were initially identified by univariate logistic regression analysis. As shown in Table 3, age, serum potassium levels, LAD, NYHA class, hospitalization period and GNRI were significantly associated with POAF (all p < 0.05). Multivariate logistic regression analysis, which included age, serum potassium level, LAD, hospitalization period, NYHA class, and GNRI, showed that only age (adjusted odds ratio [OR], 1.03; 95% confidence interval [CI] 1.02-1.07; p = 0.010), hospitalization period (adjusted OR, 1.10; 95% CI 1.04-1.15; p < 0.001), NYHA class (adjusted OR, 2.54; 95% CI 1.44-4.49; p = 0.001, v NYHA class I-II), and GNRI (adjusted OR, 2.78; 95% CI 1.61-4.82; p < 0.001, v GNRI ≥98) independently predicted POAF.
      Table 3Risk factors of POAF as Determined by Univariate and Multivariate Logistic Regression Analyses
      VariableUnivariateMultivariate
      OR (95% CI)p ValueOR (95% CI)p Value
      Age (y)1.05 (1.03-1.07)<0.0011.03 (1.02-1.07)0.010
      Sex (male)0.79 (0.49-1.28)0.340
      Hypertension1.11 (0.70-1.76)0.664
      Diabetes mellitus0.74 (0.38-1.46)0.388
      Previous cardiac surgery0.62 (0.32-1.22)0.168
      Serum potassium (mmol/L)2.33 (1.29-4.20)0.0051.79 (0.91-3.56)0.094
      LAD (mm)1.05 (1.02-1.08)0.0051.04 (1.00-1.08)0.750
      LVIDd (mm)1.00 (0.98-1.03)0.942
      LVIDs (mm)1.02 (0.99-1.05)0.163
      Operation time (min)1.00 (0.99-1.00)0.504
      CPB time (min)1.00 (0.99-1.02)0.777
      Cross-clamp time (min)1.00 (0.99-1.01)0.662
      Type of procedure, n (%)
      CABGReferenceReference
      Aortic valve procedure0.66 (0.32-1.37)0.263
      Mitral valve procedure0.77 (0.37-1.59)0.473
      Tricuspid valve procedure1.15 (0.07-19.25)0.923
      Double valve procedure1.45 (0.66-3.20)0.358
      CABG + valve1.05(0.40-2.77)0.917
      Aortic valve procedure + others
      Lobectomy, atrial septal repair, or myxoma operation.
      1.09 (0.48-2.46)0.834
      Mitral valve procedure + others1.15 (0.15-8.71)0.894
      Hospitalization period (d)1.13 (1.08-1.19)<0.0011.10 (1.04-1.15)<0.001
      Higher NYHA class4.39 (2.68-7.19)<0.0012.54 (1.44-4.49)0.001
      (I-II v III-IV)
      GNRI0.93 (0.90-0.96)<0.0010.96 (0.92-0.99)0.012
      Lower GNRI (<98 v ≥98)4.24 (2.60-6.94)<0.0012.78 (1.61-4.82)<0.001
      Abbreviations: CABG, coronary artery bypass surgery; CI, confidence interval; CPB, cardiopulmonary bypass; GNRI, Geriatric Nutritional Risk Index; LAD, left atrial diameter; LVIDd, left ventricular internal diameter diastolic; LVIDs, left ventricular internal diameter systolic; OR, odds ratio; POAF, postoperative atrial fibrillation.
      low asterisk Lobectomy, atrial septal repair, or myxoma operation.

      Discussion

      In this study, the authors investigated the relationship between preoperative nutrition evaluated by GNRI in POAF and outcome after cardiac surgery. The authors found that GNRI was considered to have a predictive role in POAF and was associated with an increase in the 90-day all-cause readmission rate.
      Malnutrition is common in hospitalized patients and is characterized by a decline in physical function caused by insufficient body intake, resulting in changes in body composition (decreased fat-free mass) and cell mass.
      • Cederholm T
      • Barazzoni R
      • Austin P
      • et al.
      ESPEN guidelines on definitions and terminology of clinical nutrition.
      Recent data from the United States of America and Europe
      • Gomes F
      • Schuetz P
      • Bounoure L
      • et al.
      ESPEN guidelines on nutritional support for polymorbid internal medicine patients.
      ,
      • Schuetz P
      • Seres D
      • Lobo DN
      • et al.
      Management of disease-related malnutrition for patients being treated in hospital.
      showed that nearly one-third of inpatients have malnutrition or are at risk of malnutrition at admission, and nearly half of cardiac surgery patients were malnourished preoperatively.
      • Ringaitienė D
      • Gineitytė D
      • Vicka V
      • et al.
      Preoperative risk factors of malnutrition for cardiac surgery patients.
      Because of the prevalence of malnutrition and its influence on the length of ICU/hospital stay, mortality rate, readmission rate, and hospitalization costs of patients, early detection and initiation of nutritional intervention are important.
      The GNRI is a widely accepted and easily accessible nutritional assessment tool for the geriatric patient.
      • Bouillanne O
      • Morineau G
      • Dupont C
      • et al.
      Geriatric Nutritional Risk Index: A new index for evaluating at-risk elderly medical patients.
      ,
      • Hao X
      • Li D
      • Zhang N.
      Geriatric Nutritional Risk Index as a predictor for mortality: A meta-analysis of observational studies.
      Using the formula to calculate GNRI through serum albumin, actual body weight, and ideal body weight index is very simple and easy in clinical practice. There are also many studies on the relationship between GNRI and cardiovascular diseases. Some studies
      • Lee K
      • Ahn JM
      • Kang DY
      • et al.
      Nutritional status and risk of all-cause mortality in patients undergoing transcatheter aortic valve replacement assessment using the geriatric nutritional risk index and the controlling nutritional status score.
      ,
      • Seoudy H
      • Al-Kassou B
      • Shamekhi J
      • et al.
      Frailty in patients undergoing transcatheter aortic valve replacement: Prognostic value of the Geriatric Nutritional Risk Index.
      ,
      • Naganuma M
      • Kudo Y
      • Suzuki N
      • et al.
      Effect of malnutrition and frailty status on surgical aortic valve replacement.
      have reported that lower GNRI was associated independently with midterm and long-term mortality in patients undergoing transcatheter aortic valve replacement and surgical aortic valve replacement. Therefore, the authors chose the GNRI for nutritional screening before cardiac surgery. Although several studies
      • Lee SI
      • Ko KP
      • Choi CH
      • et al.
      Does the prognostic nutritional index have a predictive role in the outcomes of adult cardiac surgery?.
      ,
      • Cho JS
      • Shim JK
      • Kim KS
      • et al.
      Impact of preoperative nutritional scores on 1-year postoperative mortality in patients undergoing valvular heart surgery.
      investigated the prognosis after cardiac surgery using different nutritional assessment methods (including GNRI), to the best of the authors’ knowledge, this was the first study to illustrate the predictive role of GNRI in the development of POAF in patients after cardiac surgery.
      POAF is a common complication after cardiac surgery, associated with increased risk of all-cause mortality and associated comorbidities, such as ischemic stroke and heart failure. The incidence of POAF after cardiac surgery has been reported to be approximately 20%-to-65%.
      • Rezaei Y
      • Peighambari MM
      • Naghshbandi S
      • et al.
      Postoperative atrial fibrillation following cardiac surgery: From pathogenesis to potential therapies.
      ,
      • Kadado AJ
      • Freeman J
      • Akar JG.
      Postoperative atrial fibrillation and Maslow's hammer.
      In this study, POAF occurred in 44.9% of patients. This result agreed with those previously reported. The association between malnutrition and POAF is unclear. However, studies on malnutrition and transcatheter radiofrequency ablation of AF have found that preoperative malnutrition affects the recurrence of atrial fibrillation. Kaneko et al.
      • Kaneko M
      • Nagata Y
      • Nakamura T
      • et al.
      Geriatric nutritional risk index as a predictor of arrhythmia recurrence after catheter ablation of atrial fibrillation.
      assessed the nutrition status using GNRI of 538 patients with atrial fibrillation who underwent catheter ablation, and found that malnutrition was an independent risk factor for AF recurrence. Until recently, the data regarding the association between GNRI and POAF after cardiac surgery have been lacking. In the present study, GNRI was an independent predictor of POAF. The results also suggested that lower GNRI might affect early postoperative clinical outcomes (90-day all-cause readmission). Ninety-day all-cause mortality was not significantly different between the low-risk and non-risk groups for malnutrition; this discrepancy with the results of previous studies may have been due to the small sample size and short follow-up.
      Advanced age has been recognized as a risk factor for AF. With aging, atrial cellular fibrosis and collagen deposition increase, thus altering the atrial electrophysiologic structure. This process is fundamental and makes POAF possible when exposed to external stimuli, such as interventional procedures.
      • Greenberg JW
      • Lancaster TS
      • Schuessler RB
      • et al.
      Postoperative atrial fibrillation following cardiac surgery: A persistent complication.
      The authors found that poor cardiac function is also a risk factor for the development of POAF. In a large retrospective study of 5,588 patients in the United Kingdom, Cole et al.
      • Cole OM
      • Tosif S
      • Shaw M
      • et al.
      Acute Kidney injury and postoperative atrial fibrillation in patients undergoing cardiac surgery.
      concluded that New York Heart Association class ≥III was associated with POAF. This observation was consistent with the authors’ results.
      AF and heart failure share common pathophysiologic mechanisms, and the interaction between them exacerbates the development of both AF and heart failure. Pre-existing heart failure may contribute to the development of AF through mechanisms such as the renin-angiotensin system, calcium handling, and profibrotic and proinflammatory pathways, thus promoting electrical and structural remodeling.
      • Prabhu S
      • Voskoboinik A
      • Kaye DM
      • et al.
      Atrial fibrillation and heart failure - cause or effect?.
      It is unclear whether their poor nutritional status accelerates POAF occurrence or if manipulation during cardiac interventional procedures is responsible for POAF development. In conclusion, assessment of patients' nutritional status and prompt nutritional support may be a good periprocedural strategy to diminish the risk of POAF and improve outcomes.

      Limitations

      First, this was a single institutional retrospective study with a small sample size (292 patients), which may not be representative. Therefore, a multicenter and prospective randomized controlled trial with a large sample size is required for further validation. Second, the authors only investigated the relationship between the nutritional status and POAF and did not further investigate the outcome after nutritional improvement. In future studies, this relationship should be investigated after the nutritional status has improved, with a larger sample from multiple centers. Finally, intraoperative data that may affect outcomes were not collected in this study because of the limited availability of resources.

      Conclusion

      The easily accessible GNRI used for preoperative nutritional assessment before cardiac surgery can predict the incidence POAF and is related to short-term readmission rates.

      Conflict of Interest

      None.

      Funding

      The study was supported by the Zhejiang Provincial Health Commission Project (No.2018KY004) and Scientific Research Fund of Zhejiang Provincial Education Department (No. Y201738256).

      References

        • Rezaei Y
        • Peighambari MM
        • Naghshbandi S
        • et al.
        Postoperative atrial fibrillation following cardiac surgery: From pathogenesis to potential therapies.
        Am J Cardiovasc Drugs. 2020; 20: 19-49
        • Kadado AJ
        • Freeman J
        • Akar JG.
        Postoperative atrial fibrillation and Maslow's hammer.
        Anesth Analg. 2018; 126: 19-20
        • Echahidi N
        • Pibarot P
        • O'Hara G
        • et al.
        Mechanisms, prevention, and treatment of atrial fibrillation after cardiac surgery.
        J Am Coll Cardiol. 2008; 51: 793-801
        • Maisel WH
        • Rawn JD
        • Stevenson WG.
        Atrial fibrillation after cardiac surgery.
        Ann Intern Med. 2001; 135: 1061-1073
        • Aranki SF
        • Shaw DP
        • Adams DH
        • et al.
        Predictors of atrial fibrillation after coronary artery surgery. Current trends and impact on hospital resources.
        Circulation. 1996; 94: 390-397
        • Goldman SM.
        Commentary: Postoperative atrial fibrillation: “No magic bullet”.
        J Thorac Cardiovasc Surg. 2021; 161: 1812-1813
        • Gomes F
        • Schuetz P
        • Bounoure L
        • et al.
        ESPEN guidelines on nutritional support for polymorbid internal medicine patients.
        Clin Nutr. 2018; 37: 336-353
        • Schuetz P
        • Seres D
        • Lobo DN
        • et al.
        Management of disease-related malnutrition for patients being treated in hospital.
        Lancet. 2021; 398: 1927-1938
        • Ross F
        • Latham G
        • Joffe D
        • et al.
        Preoperative malnutrition is associated with increased mortality and adverse outcomes after paediatric cardiac surgery.
        Cardiol Young. 2017; 27: 1716-1725
        • Hill A
        • Arora RC
        • Engelman DT
        • et al.
        Preoperative treatment of malnutrition and sarcopenia in cardiac surgery: New frontiers.
        Crit Care Clin. 2020; 36: 593-616
        • Chermesh I
        • Hajos J
        • Mashiach T
        • et al.
        Malnutrition in cardiac surgery: Food for thought.
        Eur J Prev Cardiol. 2014; 21: 475-483
        • Yu PJ
        • Cassiere HA
        • Dellis SL
        • et al.
        Impact of preoperative prealbumin on outcomes after cardiac surgery.
        JPEN J Parenter Enteral Nutr. 2015; 39: 870-874
        • Lomivorotov VV
        • Efremov SM
        • Boboshko VA
        • et al.
        Evaluation of nutritional screening tools for patients scheduled for cardiac surgery.
        Nutrition. 2013; 29: 436-442
        • Florath I
        • Albert AA
        • Rosendahl UP
        • et al.
        Body mass index: A risk factor for 30-day or six-month mortality in patients undergoing aortic valve replacement?.
        J Heart Valve Dis. 2006; 15: 336-344
        • Lopez-Delgado JC
        • Muñoz-Del Rio G
        • Flordelís-Lasierra JL
        • et al.
        Nutrition in adult cardiac surgery: Preoperative evaluation, management in the postoperative period, and clinical implications for outcomes.
        J Cardiothorac Vasc Anesth. 2019; 33: 3143-3162
        • Bouillanne O
        • Morineau G
        • Dupont C
        • et al.
        Geriatric Nutritional Risk Index: A new index for evaluating at-risk elderly medical patients.
        Am J Clin Nutr. 2005; 82: 777-783
        • Yoshida M
        • Nakashima A
        • Doi S
        • et al.
        Lower Geriatric Nutritional Risk Index (GNRI) is associated with higher risk of fractures in patients undergoing hemodialysis.
        Nutrients. 2021; 13: 2847
        • Li H
        • Cen K
        • Sun W
        • et al.
        Prognostic value of geriatric nutritional risk index in elderly patients with heart failure: A meta-analysis.
        Aging Clin Exp Res. 2021; 33: 1477-1486
        • Yan D
        • Shen Z
        • Zhang S
        • et al.
        Prognostic values of geriatric nutritional risk index (GNRI) and prognostic nutritional index (PNI) in elderly patients with diffuse large B-cell lymphoma.
        J Cancer. 2021; 12: 7010-7017
        • Yamana I
        • Takeno S
        • Shimaoka H
        • et al.
        Geriatric Nutritional Risk Index as a prognostic factor in patients with esophageal squamous cell carcinoma -retrospective cohort study.
        Int J Surg. 2018; 56: 44-48
        • Izawa KP
        • Watanabe S.
        Relation of nutritional status to physiological outcomes after cardiac surgery in elderly patients with diabetes mellitus: A preliminary study.
        Aging Clin Exp Res. 2016; 28: 1267-1271
        • Unosawa S
        • Taoka M
        • Osaka S
        • et al.
        Is malnutrition associated with postoperative complications after cardiac surgery?.
        J Card Surg. 2019; 34: 908-912
        • Lee K
        • Ahn JM
        • Kang DY
        • et al.
        Nutritional status and risk of all-cause mortality in patients undergoing transcatheter aortic valve replacement assessment using the geriatric nutritional risk index and the controlling nutritional status score.
        Clin Res Cardiol. 2020; 109: 161-171
        • Seoudy H
        • Al-Kassou B
        • Shamekhi J
        • et al.
        Frailty in patients undergoing transcatheter aortic valve replacement: Prognostic value of the Geriatric Nutritional Risk Index.
        J Cachexia Sarcopenia Muscle. 2021; 12: 577-585
        • Katayama T
        • Hioki H
        • Kyono H
        • Watanabe Y
        • et al.
        Predictive value of the geriatric nutritional risk index in percutaneous coronary intervention with rotational atherectomy.
        Heart Vessels. 2020; 35: 887-893
        • Cederholm T
        • Barazzoni R
        • Austin P
        • et al.
        ESPEN guidelines on definitions and terminology of clinical nutrition.
        Clin Nutr. 2017; 36: 49-64
        • Ringaitienė D
        • Gineitytė D
        • Vicka V
        • et al.
        Preoperative risk factors of malnutrition for cardiac surgery patients.
        Acta Med Litu. 2016; 23: 99-109
        • Hao X
        • Li D
        • Zhang N.
        Geriatric Nutritional Risk Index as a predictor for mortality: A meta-analysis of observational studies.
        Nutr Res. 2019; 71: 8-20
        • Naganuma M
        • Kudo Y
        • Suzuki N
        • et al.
        Effect of malnutrition and frailty status on surgical aortic valve replacement.
        Gen Thorac Cardiovasc Surg. 2022; 70: 24-32
        • Lee SI
        • Ko KP
        • Choi CH
        • et al.
        Does the prognostic nutritional index have a predictive role in the outcomes of adult cardiac surgery?.
        J Thorac Cardiovasc Surg. 2020; 160 (e3): 145-153
        • Cho JS
        • Shim JK
        • Kim KS
        • et al.
        Impact of preoperative nutritional scores on 1-year postoperative mortality in patients undergoing valvular heart surgery.
        J Thorac Cardiovasc Surg. 2022; 164 (e3): 1140-1149
        • Kaneko M
        • Nagata Y
        • Nakamura T
        • et al.
        Geriatric nutritional risk index as a predictor of arrhythmia recurrence after catheter ablation of atrial fibrillation.
        Nutr Metab Cardiovasc Dis. 2021; 31: 1798-1808
        • Greenberg JW
        • Lancaster TS
        • Schuessler RB
        • et al.
        Postoperative atrial fibrillation following cardiac surgery: A persistent complication.
        Eur J Cardiothorac Surg. 2017; 52: 665-672
        • Cole OM
        • Tosif S
        • Shaw M
        • et al.
        Acute Kidney injury and postoperative atrial fibrillation in patients undergoing cardiac surgery.
        J Cardiothorac Vasc Anesth. 2020; 34: 1783-1790
        • Prabhu S
        • Voskoboinik A
        • Kaye DM
        • et al.
        Atrial fibrillation and heart failure - cause or effect?.
        Heart Lung Circ. 2017; 26: 967-974