Preoperative hyponatremia predicts outcomes after cardiac surgery

Postoperative hypernatremia is associated with worse brain injuries on EEG and MRI following pediatric cardiac surgery

Objectives

Dysnatremia is a common electrolyte disturbance after cardiopulmonary bypass (CPB) surgery for congenital heart disease (CHD) and a known risk factor for adverse neurological events and clinical outcomes. The objective of this study was to evaluate the association of dysnatremia with worse abnormal EEG patterns, brain injuries detected by magnetic resonance imaging (MRI) and early adverse outcomes.

Methods

We monitored continuous EEG in 340 children during the initial 48 h following cardiac surgery. Demographics and clinical characteristics were recorded. Sodium concentrations were measured in the arterial blood gas analysis every 6 h. Hyponatremia and hypernatremia were classified by the average of sodium concentrations over 48 h. Postoperative cerebral MRI was performed before hospital discharge.

Results

In our patient cohort, dysnatremia was present in 46 (13.5%) patients. Among them, hyponatremia occurred in 21 (6.2%) and hypernatremia in 25 (7.4%). When compared to patients with normonatremia, hyponatremia was not associated with EEG abnormalities and early adverse outcomes (Ps ≥ .14). In hypernatremia group, the CPB time was significantly longer and more frequent use of DHCA (Ps ≤ .049). After adjusting for time, CPB time and the use of DHCA, hypernatremia was significantly associated with worse EEG abnormalities (including background, seizures and pathological delta brushes), more severe brain injuries on MRI (Ps ≤ .04) and trended to be associated with longer postoperative mechanical ventilation time (P = .06).

Conclusion

Hypernatremia and hyponatremia were common in children after cardiac surgery. Hypernatremia, but not hyponatremia, was significantly associated with worse EEG abnormalities and more severe brain injuries on MRI and extended postoperative mechanical ventilation time.

Association between preoperative serum sodium and postoperative 30-day mortality in adult patients with tumor craniotomy

BACKGROUND

Limited data exist regarding preoperative serum sodium (Na) and 30-day mortality in adult patients with tumor craniotomy. Therefore, this study investigates their relationship.

METHODS

A secondary retrospective analysis was performed using data from the ACS NSQIP database (2012-2015). The principal exposure was preoperative Na. The outcome measure was 30-day postoperative mortality. Binary logistic regression modeling was conducted to explore the link between them, and a generalized additive model and smooth curve fitting were applied to evaluate the potential association and its explicit curve shape. We also conducted sensitivity analyses and subgroup analyses.

RESULTS

A total of 17,844 patients (47.59% male) were included in our analysis. The mean preoperative Na was 138.63 ± 3.23 mmol/L. The 30-day mortality was 2.54% (455/17,844). After adjusting for covariates, we found that preoperative Na was negative associated with 30-day mortality. (OR = 0.967, 95% CI:0.941, 0.994). For patients with Na ≤ 140, each increase Na was related to a 7.1% decreased 30-day mortality (OR = 0.929, 95% CI:0.898, 0.961); for cases with Na > 140, each increased Na unit was related to a 8.8% increase 30-day mortality (OR = 1.088, 95% CI:1.019, 1.162). The sensitivity analysis and subgroup analysis indicated that the results were robust.

CONCLUSIONS

This study shows a positive and nonlinear association between preoperative Na and postoperative 30-day mortality in adult patients with tumor craniotomy. Appropriate preoperative Na management and maintenance of serum Na near the inflection point (140) may reduce 30-day mortality.

Association of preoperative hyponatremia with surgical outcomes: a systematic review and meta-analysis of 32 observational studies

BACKGROUND

Preoperative hyponatremia is prevalent in patients undergoing surgical procedures, but it is uncertain if hyponatremia will lead to increased risk of surgical mortality and morbidity.

METHODS

A systematic search of Medline (PubMed), Embase and Cochrane Library from inception till 2 July 2021 was performed. Full length articles that reported on the association between surgical outcomes among adults ≥18 years with documented preoperative hyponatremia were included.

FINDINGS

We identified 32 observational studies comprising 1,301,346 participants. All studies had low risk of bias. When adjusted for covariates, patients with hyponatremia had significantly higher odds of developing major complications (defined as a composite measure of 9 major complications) compared to patients with normal sodium concentrations (aOR =  1.37, 95%CI = 1.23-1.53, I2 = 78%. N = 10). Additionally, patients with preoperative hyponatremia also significantly higher hazards of early mortality (<90 days) compared to patients with normonatremia (aHR = 1.27, 95%CI = 1.13-1.43, I2 = 97%. N = 10) after adjustment for covariates. Preoperative hyponatremia also had significant associations with respiratory, renal and septic complications. In terms of prognostic performance, preoperative hyponatremia performed adequately in predicting major complications in surgical patients (AUC = 0.70, LR- 0.90) with a specificity of 88% and a sensitivity of 25%.

INTERPRETATION

Our meta-analysis suggests that preoperative hyponatremia is associated with poorer early mortality and major morbidity outcomes in surgical patients. Hyponatremia is also a specific prognosticator for major complications in surgical patients, reiterating its potential use as a clinical indicator of poor outcomes.

Does Hyponatremia Affect the Short-Term Outcomes of Colorectal Cancer Surgery: A Propensity Score Matching Analysis

Purpose

The purpose of the current study is to analyze whether preoperative hyponatremia affected the short-term outcomes of colorectal cancer (CRC) surgery.

Methods

This retrospective study was conducted in a single clinical center where we enrolled patients who underwent primary CRC surgery from January 2011 to December 2021. The short-term outcomes were compared between the hyponatremia group and the normal sodium group using propensity score matching (PSM) analysis.

Results

A total of 6730 cases of patients who received CRC surgery were finally included in this study. There were 184 patients in the hyponatremia group and 6546 patients in the normal sodium group. After 1 : 1 ratio PSM, 184 patients in the normal sodium group were matched to 184 patients in the hyponatremia group. No significant difference was found in baseline information after PSM (P > 0.05). After PSM, the hyponatremia group had higher patients with overall complications (P = 0.013). Univariate and multivariate logistic regression analysis were conducted to find predictors of complications, and we found that older age (P = 0.032, OR = 1.023, 95%CI = 1.002 − 1.044), open surgery (P =0.001, OR = 2.300, 95%CI = 1.420 − 3.727), blood loss (P = 0.015, OR = 1.002, 95%CI = 1.000 − 1.003), and hyponatremia (P = 0.012, OR = 1.856, 95%CI = 1.148 − 3.001) were independent predictors of patients with overall complications.

Conclusion

Hyponatremia was an independent predictor of patients with overall complications after CRC surgery, therefore, the adequate preparation of the patients for surgery remained fundamental.

Hyponatremia-A New Diagnostic Marker for Complicated Acute Appendicitis in Children: A Systematic Review and Meta-Analysis

Background: Acute appendicitis in the pediatric population remains a diagnostic challenge for clinicians. Despite many biochemical markers, imaging modalities and scoring systems, initial misdiagnosis and complication rates are high in children. This suggests the need for investigations directed towards new diagnostic tools to aid in the diagnosis. Recent studies have shown a correlation between serum sodium levels and complicated appendicitis. Although the exact reasons for hyponatremia in patients with complicated appendicitis are not known, there is persuasive data to support the role of pro-inflammatory cytokines such as IL-6 in the non-osmotic release of antidiuretic hormone. This meta-analysis aims to investigate all available data on hyponatremia as a diagnostic marker of complicated appendicitis in the pediatric population. Methods: The literature search was conducted by two independent investigators according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The scientific databases (PubMed, EMBASE, Web of Science, and Scopus) were systematically searched for relevant studies using the keywords (hyponatremia) AND (appendicitis) AND (children). The methodological quality was assessed using a validated scale, and RevMan 5.4 software was utilized for pooled analysis. Results: Seven studies were included in the final meta-analysis, five of which were retrospective. A total of 1615 and 2808 cases were distributed into two groups: group A with complicated appendicitis and group B with uncomplicated acute appendicitis, respectively. The studies compared serum sodium levels of patients among the groups. Pooling the data demonstrated significantly lower serum sodium levels in children with complicated appendicitis vs. the non-complicated appendicitis (WMD: −3.29, 95% CI = −4.52 to −2.07, p < 0.00001). The estimated heterogeneity among the included studies was substantial and statistically significant (I2 = 98%, p < 0.00001). Conclusion: The results of the present meta-analysis indicate that hyponatremia has potential to be utilized as a biochemical marker in the diagnosis of complicated appendicitis in the pediatric population. However, well designed prospective diagnostic efficiency studies are essential to consolidate the association between hyponatremia and complicated acute appendicitis.

Severe hyponatraemia in a patient with a large left atrial myxoma: a case report

Background

Atrial myxomas (AMs) are the most commonly encountered cardiac tumours. They can be genetically inherited and are commonly found in the left atrium. They usually present with dyspnoea, syncopal episodes, heart failure from mitral valve obstruction, and constitutional symptoms including weight loss, fatigue, and fever. We present a rare case of severe symptomatic hyponatraemia secondary to a large AM and discuss possible aetiology.

Case summary

A 75-year-old Caucasian female presented with acute nausea, vomiting, confusion, and drowsiness. She had a background of palpitations for about 20 years. Her blood test results revealed severe hyponatraemia (serum sodium—103 mmol/L). Further investigations for hyponatraemia including serum cortisol and urine biochemistry suggested Syndrome of Inappropriate Anti-Diuretic Hormone (SIADH) secretion. Computer tomography scan revealed an incidental large left AM. Echocardiography confirmed the AM attached to the left side of the inter-atrial septum and occupying the majority of the left atrium. She was treated medically for hyponatraemia and referred for excision of myxoma. She underwent urgent resection of the myxoma once sodium levels were optimized. Postoperatively, her serum sodium remained low but gradually returned to normal on postoperative Day 11.

Conclusion

This is only the third reported case of significant hyponatraemia associated with a large AM. It has been previously hypothesized that large left AM stretch the atrium causing release of atrial natriuretic peptide and subsequent hyponatraemia. The excision of myxoma and reduction in left atrial size postoperatively with an improvement in sodium levels suggests an association between the two pathologies.

Sodium Abnormalities Are an Independent Predictor of Complications in Total Joint Arthroplasty: A Cautionary Tale!

BACKGROUND

Electrolyte levels are commonly obtained as part of the preoperative workup for total joint arthroplasty, but limited information exists on the interplay between electrolyte abnormalities and outcomes.

METHODS

The National Surgical Quality Improvement Program was queried for primary, elective total hip arthroplasty and total knee arthroplasty (THA, TKA) performed between 2011 and 2017. Three patient groups were compared: normal (control), hypernatremia, and hyponatremia. The primary outcomes were length of stay (LOS) and 30-day adverse events: complications, readmissions, reoperations, and mortality.

RESULTS

A total of 244,538 TKAs and 145,134 THAs were analyzed. The prevalence of hyponatremia and hypernatremia was 6.9% and 1.0%, respectively. After controlling for any baseline differences, hypernatremia was an independent predictor of ventilation >48 hours (THA, odds ratio [OR] 3.53), unplanned intubation (THA, OR 3.14), cardiac arrest (THA, OR 2.42), pneumonia (THA, OR 2.16), Clostridium difficile infection (OR 4.66 and 3.25 for THA and TKA, respectively), LOS >2 days (THA, OR 1.16), and mortality (THA, OR 4.69). Similarly, hyponatremia was an independent predictor of LOS >2 days (TKA, OR 1.21), readmission (TKA, OR 1.40), reoperation (OR 1.32 and 1.47 for THA and TKA, respectively), surgical site infections (OR 1.39 and 1.54 for THA and TKA, respectively), and transfusion (OR 1.13 and 1.20 for THA and TKA, respectively).

CONCLUSION

As the focus of total joint arthroplasty continues to shift toward value-based payment models and outpatient surgery, caution should be exercised in patients with abnormal preoperative sodium levels, particularly hypernatremia, because of significantly increased risk of prolonged LOS and 30-day adverse events.

Preoperative hyponatremia predicts complications in older patients undergoing digestive tract surgery: a propensity score matching analysis

Aim

This study aimed to investigate the association between preoperative hyponatremia and life-threatening postoperative complications (including death) among older patients undergoing digestive tract surgery.

Findings

Preoperative hyponatremia was associated with an increased risk of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery. Preoperative hyponatremia was also correlated with a higher risk of postoperative infectious complications.

Message

Preoperative hyponatremia can predict the development of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41999-021-00559-4.

Purpose

Whether preoperative hyponatremia increases the risk of postoperative complications in older patients undergoing digestive tract surgery remains unclear. The purpose of the study was to investigate the association between preoperative hyponatremia and life-threatening postoperative complications (including death) among older patients undergoing digestive tract surgery.

Methods

This was a propensity score-matched, retrospective cohort study. We recruited older patients (≥ 65 years of age) who underwent digestive tract surgery in our institution. The propensity score matching (PSM; 1:2) was used to balance a range of covariates between patients with preoperative hyponatremia (serum sodium [Na⁺] levels < 135 mmol/L) and those with normal [Na⁺] levels (135–145 mmol/L). The primary outcome was the occurrence of life-threatening postoperative complications and mortality (i.e., Clavien–Dindo grade IV and V [CD IV and V] complications) during hospital stay. The relationship between preoperative hyponatremia and the development of CD IV and V complications was identified with logistic regression analysis.

Results

A total of 1076 patients were analyzed (mean age 73.9 years; 421 female [39.1%]). Preoperative hyponatremia was identified in 122 patients. After matching, 312 patients were included in the analyses (104 patients with preoperative hyponatremia and 208 patients with normal [Na⁺] levels; mean age, 76.3 years; 130 female [41.7%]). When compared with normal [Na⁺] levels, preoperative hyponatremia was associated with an increased risk of CD IV and V complications (odds ratio [OR] 2.082, 95% confidential interval [CI] 1.041–4.164, P = 0.038). Preoperative hyponatremia was also significantly associated with a higher risk of postoperative infectious complications (OR 2.158, 95% CI 1.138–4.091, P = 0.018).

Conclusion

Preoperative hyponatremia can predict an increased risk of life-threatening postoperative complications and mortality in older patients undergoing digestive tract surgery.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41999-021-00559-4.

Elevated serum sodium in recipients of liver transplantation has a substantial impact on outcomes

Dysnatremias are a rare but significant event in liver transplantation. While recipient pre-transplant hypernatremia has been demonstrated to increase post-transplant mortality, the degree of hypernatremia and the impact of its resolution have been less well characterized. Here, we used multivariate Cox regression with a comprehensive list of donor and recipient factors in order to conduct a robust multivariate retrospective database study of 54,311 United Network for Organ Sharing (UNOS) liver transplant patients to analyze the effect of pre-transplant serum sodium on post-transplant mortality, post-transplant length of hospitalization, and post-transplant graft survival. Mortality and graft failure increased in a stepwise fashion with increasing pre-transplant hypernatremia: 145 -150 mEq/L (HR = 1.118 and HR = 1.113), 150-155 mEq/L (HR = 1.324 and HR = 1.306), and > 155 mEq/L (HR = 1.623 and HR = 1.661). Pre-transplant hypo- and hypernatremia also increased length of post-transplant hospitalization: < 125 mEq/L (HR = 1.098), 125-130 mEq/L (HR = 1.060), 145 -150 mEq/L (HR = 1.140), and 150-155 mEq/L (HR = 1.358). Resolution of hypernatremia showed no significant difference in mortality compared with normonatremia, while unresolved hypernatremia significantly increased mortality (HR = 1.254), including a durable long-term increased mortality risk for patients with creatinine < 2 mg/dL and MELD < 25. Pre-transplant hypernatremia serves as a morbid prognostic indicator for post-transplant morbidity and mortality.

Hyponatremia: An Overlooked Risk Factor Associated With Adverse Outcomes After Cardiac Surgery

BACKGROUND

Hyponatremia is an unrecognized risk factor for adverse outcomes after cardiac surgery. We sought to study the prevalence of preoperative hyponatremia and its impact on short-term and long-term outcomes after cardiac surgery.

METHODS

Patients who had coronary artery bypass graft, valve, or coronary artery bypass graft and valve procedures from 2000 to 2016 and available preoperative serum sodium values within 30 days of the index procedure were included in the study. The effect of preoperative sodium on short-term and long-term outcomes was analyzed as a continuous and binary (hyponatremia [Na+ <135 mEq/L] versus no hyponatremia) predictor variable in multivariable regression models.

RESULTS

Preoperative hyponatremia was present in 9.9% of 16,238 patients with available sodium levels. Comorbidities were more common in patients with hyponatremia. Hyponatremia was independently associated with operative mortality (odds ratio [OR] = 1.80; 95% confidence interval [CI], 1.38-2.34; P < .001), long-term mortality (hazard ratio = 1.31; 95% CI, 1.21-1.40; P < .001), longer postoperative length of stay (hazard ratio = 1.35; 95% CI, 1.28-1.43; P < .001), renal failure (OR = 1.52; 95% CI, 1.20-1.93; P < .001), prolonged ventilation use (OR = 1.52; 95% CI, 1.30-1.78; P < .001), and stroke or transient ischemic attack (OR = 1.48; 95% CI, 1.09-2.02; P = .013). Severity of hyponatremia, as measured by sodium level, was similarly associated with increased risk for death and postoperative complications.

CONCLUSIONS

Preoperative hyponatremia is relatively common and is associated with adverse short-term and long-term outcomes after cardiac surgery. Preoperative hyponatremia can be used independently from standard risk factors to identify high-risk patients for cardiac surgery.

Sodium Abnormalities in Cardiac Surgery With Cardiopulmonary Bypass in Adults: A Narrative Review

Perioperative sodium abnormalities or dysnatremia is not uncommon in patients presenting for cardiac surgery and is associated with increased morbidity and mortality. Both the disease process of heart failure and its treatment may contribute to abnormalities in serum sodium concentration. Serum sodium is the main determinant of serum osmolality, which in turn affects cell volume. Brain cells are particularly vulnerable to changes in serum osmolality because of the nondistensible cranium. The potentially catastrophic neurologic sequelae of rapidly correcting chronic dysnatremia and the time-sensitive nature of cardiac surgery can make the management of these patients challenging. The use of cardiopulmonary bypass to facilitate surgery adds another layer of complexity in the intraoperative management of sodium and water balance. This narrative review examines the definition and classification of dysnatremia. It also covers the etiology and pathophysiology of dysnatremia, implications during cardiac surgery requiring cardiopulmonary bypass, and the perioperative management of dysnatremia.

A Simple Predictive Factor for Mortality in Fontan Surgery: Serum Hypo-Osmolality

OBJECTIVE

Close follow-up is important after the Fontan procedure, which is a palliative surgical method for a single ventricle. In this period, serum osmolality is an important parameter with the advantages of easy to obtain and poor outcome prediction.

METHODS

Patients who had undergone Fontan operation between May 2011 and February 2017 were retrospectively evaluated. Patients were divided into three groups based on their serum osmolality values: hypoosmolar (Group 1), isosmolar (Group 2), and hyperosmolar (Group 3). Demographics, clinical information and postoperative data of the groups were compared.

RESULTS

Forty-three patients had undergone extracardiac Fontan operation in the study period. There were 8, 19 and 16 patients in Groups 1, 2 and 3, respectively. Among the three groups, postoperative intubation and length of hospital stay, prolonged pleural effusion, need for inotropic support and mortality were statistically significantly higher in Group 1.

CONCLUSION

After the Fontan procedure, one of the determinants of cardiac output might be affected by serum osmolality. Decreased serum osmolality might be associated with poor prognosis after Fontan procedure. Serum osmolality monitoring may be beneficial to improve postoperative outcomes in these patients.

Hyponatremia associated with long-term medication use in the elderly: an analysis in general practice

INTRODUCTION The aim of this study is to determine the prevalence of hyponatremia, its association with long-term medication use and underlying chronic conditions, the rate of hospitalisation and death within 3 months from its discovery and its management in community-dwelling older people. METHODS One year of data for ~5635 patients aged >65 years was extracted from the databases of 19 general practitioners (GPs); 2569 (45.6%) were checked for hyponatremia. RESULTS Hyponatremia occurred in 205 (8.0%) of 2569 checked individuals: 78.5% (161/205) had hypertension, 31.2% (64/205) diabetes, 23.9% (49/205) chronic renal failure; 38.0% (78/205) received diuretics, 36.6% (75/205) renin-angiotensin system antagonists (ACE-I/ARB) and 9.8% (20/205) serotonin reuptake inhibitors. Drug consumption was higher in hyponatremic patients, although only diuretics, ACE-I/ARB, anti-arrhythmics and opioids were significantly associated with hyponatremia. The likelihood of hyponatremia trebled when four drugs were taken, and it was seven-fold higher with the use of six drugs. Hyponatremia was associated with a higher prevalence of chronic illnesses and higher rate of hospitalisation (13.7% vs 7.7%, P = 0.005) and death (3.9% vs 1.8%, P < 0.035). The use of at least one long-term medication was associated with hospitalisation or death in hyponatremic patients (10% vs 6.3%, P = 0.010). Less than 20% of hyponatremic patients had their sodium level checked again after 1 month. DISCUSSION Hyponatremia is not uncommon among community-living older patients, especially in patients taking medications potentially causing hyponatremia. Hyponatremic patients are likely to encounter more serious events, including hospitalisation and death. Targeted training of GPs is desirable to improve their practice.

Modifiable Predictors of In-Hospital Mortality in Patients Undergoing Transcatheter Aortic Valve Replacement

BACKGROUND

Transcatheter aortic valve replacement (TAVR) has become an acceptable therapy for patients with severe aortic valve stenosis at high or prohibitive surgical risk. Attempts are ongoing to validate risk prediction models for in-hospital mortality after TAVR. Our aim was to define modifiable risk factors predictive of in-hospital mortality after TAVR.

METHODS

We identified patients who underwent TAVR from the 2012 database of the National Inpatient Sample. Patients who died during the index hospitalization were compared to those that were successfully discharged. The predictors of in-hospital mortality were analyzed using multivariate logistic regression.

RESULTS

A total of 1,360 patients (mean age 81 ± 8.8 years, whites 80.1%, blacks 3.5%) had TAVR and 68 (5%) died during hospitalization (χ2 [1, n = 1,360] = 1,101.6, P < 0.001). The average length of hospital stay was 8.33 ± 6.7 days. The positive predictors of in-hospital mortality in the unadjusted model were comorbidities such as congestive heart failure, coagulopathy, fluid and electrolyte disorder, weight loss and history of drug abuse. Hypertension was a negative predictor of in-hospital mortality. Following multivariate analysis and adjustment for possible confounders, fluid and electrolyte disorder was the only significant positive predictor of in-hospital mortality (odds ratio = 1.89, CI: 1.11-3.22, P = 0.019). The odds of in-hospital mortality were reduced in patients with hypertension (odds ratio = 0.45, CI: 0.26-0.78, P = 0.004).

CONCLUSIONS

Fluid and electrolyte disturbance could be a modifiable predictor of in-hospital mortality following TAVR. Efforts should be geared towards reducing its occurrence in this patient population.

Hyponatremia Predicts Poor Outcomes in Patients With Chronic Kidney Disease Undergoing Heart Operation

BACKGROUND

Preoperative hyponatremia adversely affects outcomes of cardiothoracic operation. However, in patients with chronic kidney disease, the association of sodium levels on postoperative events has never been evaluated. We investigated the impact of preoperative hyponatremia on outcomes after cardiac operation in patients with non-dialysis-dependent chronic kidney disease. Primary end points were operative mortality and acute kidney injury that required dialysis. Secondary end points were major infection and long-term survival.

METHODS

The study is observational and includes all patients with stage III to IV chronic kidney disease (non-dialysis) undergoing cardiac operation between February 2000 and January 2016. Patients were stratified into two groups by preoperative sodium levels: sodium less than 135 mEq/L and sodium of 135 mEq/L or more.

RESULTS

There were 1,008 patients (mean estimated glomerular filtration rate [GFR]: 43 ± 14 mL • min^-1 • 1.73 m^-2) with 92 patients (9%) in the low-sodium group. Patients with low sodium had higher operative mortality (p = 0.0004), need for new dialysis (p = 0.0008), and infection (p = 0.002). Predictors of operative mortality were European System for Cardiac Operative Risk Evaluation (EuroSCORE) (hazard ratio [HR] 1.03. 95% confidence interval [CI]: 1.02 to 1.05, p < 0.0001), decreasing values of sodium (HR 1.14. 95% CI: 1.07 to 1.2, p = 0.0002), and decreasing values of GFR (HR 1.01, 95% CI: 1.003 to 1.03, p = 0.007). Sodium less than 135 mEq/L was independently associated with increased need for dialysis (HR 1.3, 95% CI: 1.1 to 1.7, p = 0.0008). By linear regression, decreasing values of preoperative sodium were proportionate to the incidence of operative mortality (p < 0.0001) and need for dialysis (p < 0.0001).

CONCLUSIONS

Preoperative hyponatremia is a predictor of increased mortality and other adverse events in patients with non-dialysis-dependent chronic kidney disease undergoing cardiac operation. These findings are similar to those in hyponatremic patients without kidney disease.

Prospective study on long-term outcome after abdominal surgery

BACKGROUND

Complications following major abdominal surgery are common and an important cause of morbidity and mortality. The aim of this study was to describe 1-year mortality and identify factors that influence adverse outcomes after abdominal surgery.

METHODS

This prospective observational cohort study was performed in Landspitali University Hospital and included all adult patients undergoing abdominal surgery requiring > 24-h hospital admission over 13 months. The follow-up period was 60 days for complications and 24 months for mortality.

RESULTS

Data were available for 1113 (99.5%) of the 1119 patients who fulfilled inclusion criteria. A total of 23% of patients had at least one underlying co-morbidity. Non-elective surgeries were 48% and 13% of the patients were admitted to ICU post-operatively. A total of 20% of patients developed complications. Mortality at 30 days, 1 and 2 years was 1.8%, 5.6%, and 8.3% respectively. One-year mortality for those admitted to ICU was 18%. The long-term survival of the individuals surviving 30 days was significantly worse than for an age- and gender-matched population control group. Independent predictors for 1-year mortality were age, pre-operative acute kidney injury and intermediate- or major surgery.

CONCLUSION

Post-operative complication rates and mortality following abdominal surgery in Iceland were comparable or in the lower range of previously published outcomes, validating the utility of offering a full host of abdominal surgical services in geographically isolated region with a relatively small referral base.

Impact of pre-procedural hyponatremia on clinical outcomes after transcatheter aortic valve replacement: A propensity-matched analysis

BACKGROUND

Hyponatremia is associated with the increased risk of early and late mortality in patients with cardiac disease. This study aimed to assess the prognostic value of hyponatremia in patients who had undergone transcatheter aortic valve replacement (TAVR).

METHODS

We investigated 1,215 consecutive patients (mean age: 84.4 ± 5.0 years) who underwent TAVR using data from the Optimized CathEter vAlvular iNtervention (OCEAN)-TAVR Japanese multicenter registry. Hyponatremia was defined as a serum sodium value less than 135 mEq/L. The baseline characteristics, procedural outcomes, all-cause, cardiovascular, and non-cardiovascular mortality were compared between patients with hyponatremia (n = 106, 8.7%) and without hyponatremia (n = 1,109, 91.3%). A propensity-matching analysis was used to adjust for the non-uniform patient characteristics.

RESULTS

Differences in the baseline characteristics were observed between the two groups regarding the prevalence of pulmonary disease (37.7% vs. 28.9%, P = 0.04) and the performance of non-elective TAVR (10.4% vs. 4.2%, P = 0.01), although these were minimized in the matched model. The 30-day mortality rates differed between the two groups (7.6% vs. 1.4%, P < 0.001). During a mean follow-up of 330 days, the all-cause and cardiovascular mid-term mortality were higher in the hyponatremia group than in the non-hyponatremia group (log-rank test: P = 0.0047, and P < 0.001, respectively). The three findings above were not attenuated in the propensity-matched model (P < 0.001, P = 0.0044, and P = 0.014, respectively). In contrast, there was no difference in non-cardiovascular mortality between the two groups in both the overall and matched model (P = 0.40 and P = 0.13, respectively).

CONCLUSIONS

Pre-procedural hyponatremia may be a useful marker for predicting early and mid-term clinical outcomes after TAVR.

Hyponatremia: A clinical approach

Hyponatremia is the most common electrolyte metabolic abnormality in clinical practice. The unfavorable course of many diseases is associated with hyponatremia. Acute severe hyponatremia is life-threatening because cerebral edema may develop. Less obvious chronic hyponatremia increases the risk of balance problems, falls and fractures, especially in elderly patients. In any occasion, hyponatremia should not be now regarded only as a laboratory phenomenon in critically ill patients, but it necessitates a thorough clinical analysis of each individual case and appropriate therapy. The paper presents approaches to diagnosing and treating hyponatremia in various clinical situations.

Preoperative serum potassium predicts the clinical outcome after non-cardiac surgery

BACKGROUND

Potassium disorders have been linked to adverse outcomes in various medical conditions. However, the association of preoperative serum potassium with postoperative outcome is not well established. We aimed to examine the association between preoperative potassium with a 30-day mortality and adverse cardiovascular event (MACE).

METHODS

We conducted a cohort study using a prospectively collected database of patients, undergoing surgical procedures from 1998 to 2013 in the VA Western New York Healthcare System, which are reported to the Veterans Affairs Surgical Quality Improvement Program (VASQIP). The patients were categorized into three groups based on their documented preoperative potassium concentrations. Hypokalemia was defined as serum potassium concentration <4 mmol/L and hyperkalemia was defined as serum potassium concentrations >5.5 mmol/L. The values within the range of 4.0-5.5 mmol/L were considered as normokalemia and used as the control group. Statistical analyses included Chi-square test, analysis of variance and multivariate logistic regression to estimate the risk of MACE within 30 days of surgery.

RESULTS

Study included 5959 veterans who underwent surgery between 1998 and 2013. The patients in the hyperkalemics group had lower kidney function compared to the other two groups. The frequency of MACE was 13.6% in hypokalemics and 21.9% in hyperkalemics that were both significantly higher than 4.9% in controls. In multivariate logistic regression the hazard risk (HR) ratios of MACE were (2.17, 95% CI 1.75-2.70) for hypokalemics and (3.23, 95% CI 2.10-4.95) for hyperkalemics when compared to normokalemic controls.

CONCLUSIONS

Preoperative hypokalemia and hyperkalemia are both independent predictors of MACE within 30 days.

The Economic Burden of Hyponatremia: Systematic Review and Meta-Analysis

BACKGROUND

Hyponatremia is the most common electrolyte abnormality observed in clinical practice. Several studies have demonstrated that hyponatremia is associated with an increased length of hospital stay and of hospital resource utilization. To clarify the impact of hyponatremia on the length of hospitalization and costs, we performed a meta-analysis based on published studies that compared hospital length of stay and cost between patients with and without hyponatremia.

METHODS

An extensive Medline, Embase, and Cochrane search was performed to retrieve all studies published up to April 1, 2015 using the following words: "hyponatremia" or "hyponatraemia" AND "hospitalization" or "hospitalisation." A meta-analysis was performed including all studies comparing duration of hospitalization and hospital readmission rate in subjects with and without hyponatremia.

RESULTS

Of 444 retrieved articles, 46 studies satisfied the inclusion criteria, encompassing a total of 3,940,042 patients; among these, 757,763 (19.2%) were hyponatremic. Across all studies, hyponatremia was associated with a significantly longer duration of hospitalization (3.30 [2.90-3.71; 95% CIs] mean days; P < .000). Similar results were obtained when patients with associated morbidities were analyzed separately. Furthermore, hyponatremic patients had a higher risk of readmission after the first hospitalization (odds ratio 1.32 [1.18-1.48; 95% CIs]; P < .000). A meta-regression analysis showed that the hyponatremia-related length of hospital stay was higher in males (Slope = 0.09 [0.05-0.12; 95% CIs]; P = .000 and Intercept = -1.36 [-3.03-0.32; 95% CIs]; P = .11) and in elderly patients (Slope = 0.002 [0.001-0.003; 95% CIs]; P < .000 and Intercept = 0.89 [0.83-0.97; 95% CIs]; P < .001). A negative association between serum [Na(+)] cutoff and duration of hospitalization was detected. No association between duration of hospitalization, serum [Na(+)], and associated morbidities was observed. Finally, when only US studies (n = 8) were considered, hyponatremia was associated with up to around $3000 higher hospital costs/patient when compared with the cost of normonatremic subjects.

CONCLUSIONS

This meta-analysis confirms that hyponatremia is associated with a prolonged hospital length of stay and higher risk of readmission. These observations suggest that hyponatremia may represent one important determinant of the hospitalization costs.

Predicting the risk of death following coronary artery bypass graft made simple: a retrospective study using the American College of Surgeons National Surgical Quality Improvement Program database

INTRODUCTION

Risk models to predict 30-day mortality following isolated coronary artery bypass graft is an active area of research. Simple risk predictors are particularly important for cardiothoracic surgeons who are coming under increased scrutiny since these physicians typically care for higher risk patients and thus expect worse outcomes. The objective of this study was to develop a 30-day postoperative mortality risk model for patients undergoing CABG using the American College of Surgeons National Surgical Quality Improvement Program database.

MATERIAL AND METHODS

Data was extracted and analyzed from the American College of Surgeons National Surgical Quality Improvement Program Participant Use Files (2005-2010). Patients that had ischemic heart disease (ICD9 410-414) undergoing one to four vessel CABG (CPT 33533-33536) were selected. To select for acquired heart disease, only patients age 40 and older were included. Multivariate logistic regression analysis was used to create a risk model. The C-statistic and the Hosmer-Lemeshow goodness-of-fit test were used to evaluate the model. Bootstrap-validated C-statistic was calculated.

RESULTS

A total of 2254 cases met selection criteria. Forty-nine patients (2.2%) died within 30 days. Six independent risk factors predictive of short-term mortality were identified including age, preoperative sodium, preoperative blood urea nitrogen, previous percutaneous coronary intervention, dyspnea at rest, and history of prior myocardial infarction. The C-statistic for this model was 0.773 while the bootstrap-validated C-statistic was 0.750. The Hosmer-Lemeshow test had a p-value of 0.675, suggesting the model does not overfit the data.

CONCLUSIONS

The American College of Surgeons National Surgical Quality Improvement Program risk model has good discrimination for 30-day mortality following coronary artery bypass graft surgery. The model employs six independent variables, making it easy to use in the clinical setting.

Moderate-to-large increases in perioperative serum sodium concentration associated with adverse neurologic events after continuous flow left ventricular assist device implantation

OBJECTIVE

It was hypothesized that preoperative hyponatremia is associated with increased 30-day mortality after left ventricular assist device placement, and that large increases in sodium concentration are associated with adverse neurologic events and 30-day mortality.

DESIGN

Data were collected retrospectively on all patients having continuous flow left ventricular assist device implantation between January 1, 2009 and March 31, 2013. Preoperative variables, operative variables, and perioperative sodium concentrations were recorded. Both 30-day mortality and 72-hour adverse neurologic events (stroke or seizure) were recorded as primary outcome variables. Preoperative sodium and Δ sodium (postoperative sodium-preoperative sodium) were analyzed as tests for 30-day mortality and adverse neurologic events using receiver operating characteristic curves. Both crude and adjusted logistic regression analyses were used to estimate odds ratios for the outcome variables.

SETTING

Tertiary care academic medical center.

PARTICIPANTS

Patients having durable continuous flow left ventricular assist device placement.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among 88 patients, 30-day mortality was 14% (12 of 88) and the rate of perioperative stroke or seizure was 9% (8 of 88). There were 3 strokes and 5 tonic-clonic seizures. Preoperative sodium was a poor discriminative test for 30-day mortality and stroke or seizure (AUC=0.47 and 0.57, respectively). Δ sodium was a poor discriminative test for 30-day mortality, but a fair discriminative test for stroke or seizure (AUC=0.55 and 0.78, respectively). Δ sodium was a good discriminative test for seizure alone (AUC=0.82) and a fair discriminative test for stroke alone (AUC=0.70). It also increased the odds of stroke or seizure significantly, even when adjusting for possible confounders.

CONCLUSIONS

Moderate-to-large increases in sodium concentration during left ventricular assist device placement appear to be associated with adverse postoperative neurologic events. Preoperative hyponatremia has no relationship with 30-day mortality or adverse perioperative neurologic events.

Hyponatraemia: more than just a marker of disease severity?

Hyponatraemia--the most common serum electrolyte disorder--has also emerged as an important marker of the severity and prognosis of important diseases such as heart failure and cirrhosis. Acute hyponatraemia can cause severe encephalopathy, but the rapid correction of chronic hyponatraemia can also profoundly impair brain function and even cause death. With the expanding elderly population and the increased prevalence of hyponatraemia in this segment of society, prospective studies are needed to examine whether correcting hyponatraemia in the elderly will diminish cognitive impairment, improve balance and reduce the incidence of falls and fractures. Given that polypharmacy is also common in the elderly population, the various medications that may stimulate arginine vasopressin release and/or enhance the hormone's action to increase water absorption must also be taken into consideration. Whether hyponatraemia in a patient with cancer is merely a marker of poor prognosis or whether its presence may alter the patient's quality of life remains to be examined. In any case, hyponatraemia can no longer be considered as just a biochemical bystander in the ill patient. A systematic diagnostic approach is necessary to determine the specific aetiology of a patient's hyponatraemia. Therapy must then be dictated not only by recognized reversible causes such as advanced hypothyroidism, adrenal insufficiency, diuretics or other medicines, but also by whether the hyponatraemia occurred acutely or chronically. Information is emerging that the vast majority of cases of hyponatraemia are caused by the nonosmotic release of arginine vasopressin. Now that vasopressin V2-receptor blockers are available, a new era of clinical investigation is necessary to examine whether hyponatraemia is just a marker of severe disease or whether correction of hyponatraemia could improve a patient's quality of life. Such an approach must involve prospective randomized studies in different groups of patients with hyponatraemia, including those with advanced heart failure, those with cirrhosis, patients with cancer, and the elderly.