Glycosylated hemoglobin levels and outcome in non-diabetic cardiac surgery patients

Elevated glycosylated hemoglobin levels are associated with severe acute kidney injury following coronary artery bypass surgery

BACKGROUND

Diabetic patients are at increased risk of acute kidney injury (AKI) following surgery. The significance of uncontrolled diabetes on kidney function after coronary artery bypass grafting (CABG) remains controversial. Our aim was to study the association between pre-operative hemoglobin A1c (HbA1c) and severe cardiac surgery-associated AKI (CSA-AKI) following CABG.

METHODS

A single-center, retrospective cohort study including patients who underwent isolated CABG from 2010 to 2018 was performed. Patients were grouped into pre-operative HbA1c of <6.5 %, 6.5-8.5 %, and ≥8.5 %. Postoperative serum creatinine levels were queried for up to 30 days, and the 30-day risk of severe AKI was compared among groups. Multivariable logistic regression was used to study factors associated with severe CSA-AKI and the association of severe CSA-AKI with postoperative outcomes. Cox regression was used to study the association between severe CSA-AKI and all-cause mortality from the time of surgery to the last follow-up or death.

RESULTS

A total of 2424 patients met the inclusion criteria. Patients were primarily male (70.5 %), with a median age of 64 years (IQR 57-71). Median bypass and cross-clamp times were 95 (IQR 78-116) and 78 min (IQR 63-95). Severe CSA-AKI occurred within 30 days in 5.7 %, 6.7 %, and 9.1 % of patients with pre-op HbA1c of <6.5 %, 6.5-8.5 %, and ≥8.5 %, respectively. After adjusting for covariates, HbA1c >8.5 %, was independently associated with severe CSA-AKI 30 days after CABG (aOR 1.59, 95%CI 1.06-2.40). In addition, severe CSA-AKI was associated with increased 30- (aOR 15.83,95%CI 7.94-31.56) and 90- day mortality (aOR 9.54, 95%CI 5.46-16.67), prolonged length of stay (aOR 3.46,95%CI 2.41-4.96) and unplanned 30-day readmission (aOR 2.64, 95%CI 1.77-3.94). Lastly, severe CSA-AKI was associated with increased all-cause mortality (aHR 3.19, 95%CI 2.43-4.17).

CONCLUSION

Elevated preoperative HbA1c (≥8.5 %) was independently associated with an increased 30-day risk of severe CSA-AKI, which is a consistent predictor of adverse outcomes after CABG. Delaying surgery to achieve optimal glycemic control in an elective setting may be reasonable.

Preoperative Glycosylated Haemoglobin Screening to Identify Older Adult Patients with Undiagnosed Diabetes Mellitus-A Retrospective Cohort Study

More than 25% of older adults in Europe have diabetes mellitus. It is estimated that 45% of patients with diabetes are currently undiagnosed, which is a known risk factor for perioperative morbidity. We investigated whether routine HbA1c screening in older adult patients undergoing surgery would identify patients with undiagnosed diabetes. We included patients aged ≥65 years without a diagnosis of diabetes who visited the preoperative assessment clinic at the Amsterdam University Medical Center and underwent HbA1c screening within three months before surgery. Patients undergoing cardiac surgery were excluded. We assessed the prevalence of undiagnosed diabetes (defined as HbA1c ≥ 48 mmol·mol-1) and prediabetes (HbA1c 39-47 mmol·mol-1). Using a multivariate regression model, we analysed the ability of HbA1c to predict days alive and at home within 30 days after surgery. From January to December 2019, we screened 2015 patients ≥65 years at our clinic. Of these, 697 patients without a diagnosis of diabetes underwent HbA1c screening. The prevalence of undiagnosed diabetes and prediabetes was 3.7% (95%CI 2.5-5.4%) and 42.9% (95%CI 39.2-46.7%), respectively. Preoperative HbA1c was not associated with days alive and at home within 30 days after surgery. In conclusion, we identified a small number of patients with undiagnosed diabetes and a high prevalence of prediabetes based on preoperative HbA1c screening in a cohort of older adults undergoing non-cardiac surgery. The relevance of prediabetes in the perioperative setting is unclear. Screening for HbA1c in older adult patients undergoing non-cardiac surgery does not appear to help predict postoperative outcome.

Investigation of the effect of acute to chronic glycemic ratio on major amputation development after surgical thromboembolectomy in patients with acute lower extremity ischemia

BACKGROUND

Acute limb ischemia (ALI) is an emergency vascular pathology in which perfusion is disrupted in the lower extremity and threatens extremity viability. The admission blood glucose (ABG)/estimated average glucose (eAG) value has recently been shown as a prognostic marker in acute cardiovascular events. In this study, we aimed to investigate the predictive role of an ABG/eAG value in predicting development of early postoperative major amputation after emergency thromboembolectomy operations in patients presenting with ALI.

METHOD

Patients who admitted to our hospital with ALI between November 01, 2016 and September 01, 2021 and underwent surgical thromboembolectomy were retrospectively included in the study. Patients who did not undergo postoperative limb amputation were recorded as Group 1, and patients who underwent major amputation in the early postoperative period (in-hospital), were recorded as Group 2.

RESULTS

The median age of the 226 patients included in Group 1 and 72 patients in Group 2 were 58 (34-86) years and 69 (33-91) years, respectively (p<0.001). In univariate analysis, in-hospital amputation was found to significantly correlate with age>70 years (odds ratio [OR]: 1.914, 95% confidence interval [CI]: 1.351-2.319, p<0.001), PAD (OR: 1.698, 95% CI: 1.270-1.992, p = 0.002 re-embolectomy (OR: 2.184, 95% CI: 1.663-3.085, p < 0.001), admission Rutherford class (OR: 0.762, 95% CI: 0.591-0.859, p = 0.032), admission time>6 h (OR: 1.770, 95% CI: 1.480-1.152, p = 0.009), ABG (OR: 1.275, 95% CI: 1.050-1.790, p < 0.001), and ABG/eAG (OR: 1.669, 95% CI: 1.315-2.239, p < 0.001).

CONCLUSION

According to our study, we can predict patient groups with a high risk of major amputation with the ABG/eAG value calculated from the blood values of the patients at the time of admission.

Use of pre-operative hemoglobin a1c to predict early post-operative renal failure and infection risks in patients who are not diabetics and undergoing elective off pump coronary artery bypass graft surgery

Background

Recent studies have indicated that patients, both with and without diabetes with an increased HbA1c, have a higher rate of adverse outcomes following cardiac surgeries. Our study is focused on to evaluate the prognostic impact of admission value of HbA1c in non-diabetic patients for postoperative renal failure and infections.

Materials and Methods

Plasma HbA1c levels were collected from 200 consecutive nondiabetic patients who got admitted for elective off pump coronary artery bypass graft (CABG) procedure over a 2-year period under two groups, Group A whose HbA1c was < 6% at admission and Group B whose HbA1c was ≥6% and ≤6.4% at admission. After surgery, patients were followed up to see if they have got infection or renal failure as postoperative complication. Student's unpaired t test was used to test the significance of difference between the quantitative variables, Yate's and Fisher's chi square tests were used for qualitative variables.

Results

We found early postoperative renal failure in 14 (3/96 in Group A and 11/104 in Group B) out of 200 patients (7%) and infection in 21 (8/96 in Group A and 13/104 in Group B) out of 200 patients (10.5%). After data analysis, it was noted that there is a positive correlation between HbA1c and postoperative renal failure (P = 0.0213) whereas no association was found between HbA1c and postoperative infections (P = 0.175) in patients undergoing off-pump CABG surgery.

Conclusion

In patients without diabetes, a plasma HbA1c ≥6% was a significant independent predictor for early postoperative renal failure.

Physiological relationship between cardiorespiratory fitness and fitness for surgery: a narrative review

Epidemiological evidence has highlighted a strong relationship between cardiorespiratory fitness and surgical outcomes; specifically, fitter patients possess heightened resilience to withstand the surgical stress response. This narrative review draws on exercise and surgical physiology research to discuss and hypothesise the potential mechanisms by which higher fitness affords perioperative benefit. A higher fitness, as indicated by higher peak rate of oxygen consumption and ability to sustain metabolic homeostasis (i.e. higher anaerobic threshold) is beneficial postoperatively when metabolic demands are increased. However, the associated adaptations with higher fitness, and the related participation in regular exercise or physical activity, might also underpin the observed perioperative benefit through a process of hormesis, a protective adaptive response to the moderate and intermittent stress of exercise. Potential mediators discussed include greater antioxidant capacity, metabolic flexibility, glycaemic control, lean body mass, and improved mood.

The association between hemoglobin A1c and all-cause mortality in the ICU: A cross-section study based on MIMIC-IV 2.0

BACKGROUND

Hyperglycemia has been reported to be associated with the outcomes of patients in the intensive care unit (ICU). However, the relationship between hemoglobin A1c (HbA1c) and long-term or short-term mortality in the ICU is still unknown. This study used the Medical Information Mart for Intensive Care (MIMIC)-IV database to investigate the relationship between HbA1c and long-term or short-term mortality among ICU patients without a diabetes diagnosis.

METHODS

A total of 3,154 critically ill patients without a diabetes diagnosis who had HbA1c measurements were extracted and analyzed from the MIMIC-IV. The primary outcome was 1-year mortality, while the secondary outcomes were 30-day mortality and 90-day mortality after ICU discharge. HbA1c levels were classified into four levels according to three HbA1c values (5.0%, 5.7%, and 6.5%). The Cox regression model was used to investigate the relationship between the highest HbA1c measurement and mortality. Finally, this correlation was validated using the XGBoost machine learning model and Cox regression after propensity score matching (PSM).

RESULTS

The study eventually included 3,154 critically ill patients without diabetes who had HbA1c measurements in the database. HbA1c levels of below 5.0% or above 6.5% were significantly associated with 1-year mortality after adjusting for covariates in Cox regression (HR: 1.37; 95% CI: 1.02-1.84 or HR: 1.62; 95% CI: 1.20-2.18). In addition, HbA1c 6.5% was linked to 30-day mortality (HR: 1.81; 95% CI: 1.21-2.71) and 90-day mortality (HR: 1.62; 95% CI: 1.14-2.29). The restricted cubic spline demonstrated a U-shaped relationship between HbA1c levels and 1-year mortality. The AUCs of the training and testing datasets in the XGBoost model were 0.928 and 0.826, respectively, while the SHAP plot revealed that HbA1c was somewhat important for the 1-year mortality. Higher HbA1c levels in Cox regression were still significantly associated with 1-year mortality after PSM for other factors.

CONCLUSIONS

The 1-year mortality, 30-day mortality, and 90-day mortality rates for critically ill patients after discharge from ICU are significantly associated with HbA1c. HbA1c < 5.0% and ≥6.5% would increase 30-day, 90-day, and 1-year mortality, while levels between 5.0% and 6.5% of HbA1c did not significantly affect these outcomes.

Predictive Value of Glycosylated Hemoglobin for Post-operative Acute Kidney Injury in Non-cardiac Surgery Patients

Objective

Recent studies have indicated that patients (both with and without diabetes) with elevated hemoglobin A1c (HbA1c) have a higher rate of acute kidney injury (AKI) following cardiac surgery. However, whether HbA1c could help to predict post-operative AKI in patients after non-cardiac surgery is less clear. This study aims to explore the predictive value of pre-operative HbA1c for post-operative AKI in non-cardiac surgery.

Methods

We reviewed the medical records of patients (≥ 18 years old) who underwent non-cardiac surgery between 2011 and 2020. Patient-related variables, including demographic and laboratory and procedure-related information, were collected, and univariable and multivariable logistic regression analyses were performed to determine the association of HbA1c with AKI. The area under the receiver operating curve (AUC), net reclassification improvement index (NRI), and integrated discriminant improvement index (IDI) were used to evaluate the predictive ability of the model, and decision curve analysis was used to evaluate the clinical utility of the HbA1c-added predictive model.

Results

A total of 3.3% of patients (94 of 2,785) developed AKI within 1 week after surgery. Pre-operative HbA1c was an independent predictor of AKI after adjustment for some clinical variables (OR comparing top to bottom quintiles 5.02, 95% CI, 1.90 to 13.24, P < 0.001 for trend; OR per percentage point increment in HbA1c 1.20, 95% CI, 1.07 to 1.33). Compared to the model with only clinical variables, the incorporation of HbA1c increased the model fit, modestly improved the discrimination (change in area under the curve from 0.7387 to 0.7543) and reclassification (continuous net reclassification improvement 0.2767, 95% CI, 0.0715 to 0.4818, improved integrated discrimination 0.0048, 95% CI, -5e-04 to 0.0101) of AKI and non-AKI cases, NRI for non-AKI improvement 0.3222, 95% CI, 0.2864 to 0.3580 and achieved a higher net benefit in decision curve analysis.

Conclusion

Elevated pre-operative HbA1c was independently associated with post-operative AKI risk and provided predictive value in patients after non-cardiac surgery. HbA1c improved the predictive power of a logistic regression model based on traditional clinical risk factors for AKI. Further prospective studies are needed to demonstrate the results and clinical application.

Clinical practice guideline: evidence, recommendations and algorithm for the preoperative optimization of anemia, hyperglycemia and smoking

Preoperative optimization has not been explored comprehensively in the surgical literature, as this responsibility has often been divided among surgery, anesthesia and medicine. We developed an evidence-based clinical practice guideline to summarize existing evidence and present diagnostic and treatment algorithms for use by surgeons caring for patients scheduled to undergo major elective surgery. We focus on 3 common comorbid conditions seen across surgical specialties - anemia, hyperglycemia and smoking - as these conditions increase complication rates in patients undergoing major surgery and can be optimized successfully as soon as 6-8 weeks before surgery. With the ability to address these conditions earlier in the patient journey, surgeons can positively affect patient outcomes. The aim of this guideline is to bring optimization in the preoperative period under the existing umbrella of evidence-based surgical care.

Guidelines for enhanced recovery after cardiac surgery. Consensus document of Spanish Societies of Anesthesia (SEDAR), Cardiovascular Surgery (SECCE) and Perfusionists (AEP)

The ERAS guidelines are intended to identify, disseminate and promote the implementation of the best, scientific evidence-based actions to decrease variability in clinical practice. The implementation of these practices in the global clinical process will promote better outcomes and the shortening of hospital and critical care unit stays, thereby resulting in a reduction in costs and in greater efficiency. After completing a systematic review at each of the points of the perioperative process in cardiac surgery, recommendations have been developed based on the best scientific evidence currently available with the consensus of the scientific societies involved.

Outcomes following coronary artery bypass surgery in diabetic treatment sub-groups. A propensity matched analysis of >7000 patients over 18 years

BACKGROUND

European System for Cardiac Operative Risk Evaluation II incorporates insulin-controlled diabetes whilst omitting tablet-controlled diabetes. Differences in adverse clinical outcomes following coronary artery bypass graft between these groups are poorly established. Therefore, a propensity matched comparison of short and longer term mortality and morbidity in insulin-controlled diabetes, tablet-controlled diabetes and non-diabetic patients was undertaken.

METHODS

Isolated first-time coronary artery bypass graft surgeries between April 1999 and April 2017 were propensity score matched by pre- and intra-operative variables.

RESULTS

8241 patients; 23.5% diabetics and 76.5% non-diabetics. The groups' demographical and clinical characteristics were comparable after matching. Insulin-controlled diabetes patients had significantly higher in-hospital mortality (3.8% vs. 1.7%, p < 0.05), multisystem failure (2.6% vs. 1.8%, p < 0.05), sternal wound infections requiring debridement (3.6% vs. 1.3%, p < 0.05), respiratory complications (25.6% vs. 21.9%, p < 0.05), new dialysis (4.7% vs. 0.9%, p < 0.05) and longer hospital stays (13.5 ± 13.3 vs. 10.6 ± 8.0, p < 0.05) compared to non-diabetic patients.Tablet-controlled diabetes patients had significantly higher strokes (2.9% vs. 1.2, p < 0.05), superficial sternal wound infections (6.7% vs. 5.4%, p < 0.05), respiratory complications (25.7% vs. 22.7%, p < 0.05), new dialysis (1.7% vs. 0.6%, p < 0.05), post-operative atrial fibrillation (37.1% vs. 33.9%, p < 0.05) and readmission with myocardial infarction (22.4% vs. 19.6%, p < 0.05) compared to non-diabetic patients.

CONCLUSION

Diabetic treatment sub-groups are an independent risk factor for sternal wound infection, new dialysis requirement, multisystem failure and readmission with myocardial infarction after isolated first coronary artery bypass graft surgery. The findings suggest the need for better risk stratification of diabetic groups prior to cardiac surgery and for improved cardiovascular risk management post-surgery in tablet-controlled diabetes patients.

Association of Preoperative Hemoglobin A1c with In-hospital Mortality Following Valvular Heart Surgery

Objective

To determine the association between the preoperative level of hemoglobin A1c (HbA1c) and in-hospital mortality in patients who underwent valvular heart surgery in our center in a retrospective cohort.

Methods

In this retrospective consecutive cohort study, patients with type 2 diabetes mellitus who were referred to our center for elective valvular surgery were enrolled and followed up. The endpoint of this study was in-hospital mortality. Based on the level of HbA1c, patients were dichotomized around a level of 7% into two groups: exposed patients with HbA1c ≥ 7% and unexposed patients with HbA1c < 7%. Then, the study variables were compared between the two groups.

Results

Two hundred twenty-four diabetic patients who were candidates for valvular surgery were enrolled; 106 patients (47.3%) had HbA1c < 7%, and 118 patients (52.6%) had HbA1c ≥ 7%. The duration of diabetes was higher in patients with HbA1c ≥ 7% (P=0.007). Thirteen (5.8%) patients died during hospital admission, of which nine patients were in the high HbA1c group. There was no significant difference between the groups regarding in-hospital mortality (P=0.899). Both the unadjusted and adjusted logistic regression models showed that HbA1c was not a predictor for in-hospital mortality (P=0.227 and P=0.388, respectively)

Conclusion

This study showed no association between preoperative HbA1c levels and in-hospital mortality in candidates for valvular heart surgery.

The Role of Glycated Hemoglobin A1c in Determining the Severity of Coronary Artery Disease in Diabetic and Non-Diabetic Subjects in Karachi

Introduction Coronary artery disease is the leading cause of death worldwide by incidence. Over the years, many studies have been conducted to find predictors of coronary artery disease; however, in the last few decades, the level of HbA1c in diabetics has been investigated as a potential predictor. Our study offers additional insight by investigating similar relationships in non-diabetic patients and by investigating potential predictors more comprehensively, making it the first of its kind study. The aim of our study is to indicate that rising HbA1c levels suggest that there's a greater risk of coronary artery disease, which can further be confirmed by the SYNTAX score, degree of stenosis, and numbers of vessels involved. Methods Data from 177 diabetic and 378 non-diabetic patients, all of whom were above 18 years of age, were included in the research. HbA1c levels (>5.6%), SYNTAX score, hypertension, number of vessels involved, and other demographic elements, such as age, smoking, and body measurements, were calculated and compared for diabetics and non-diabetics. Results HbA1c was higher in comparison to non-diabetic subjects (p <0.001). Age >53 was found to be a predictor for SYNTAX score ≥23 in diabetic patients (p <0.05). Male gender and smoking were found to be independent predictors for three-vessel disease in the non-diabetic population (p-value<0.05). There was no significant relationship between the SYNTAX score and HbA1c levels in non-diabetics (p=0.885) and diabetics. In conclusion, there is no correlation between elevated HbA1c levels and SYNTAX score ≥23.

Glycated Hemoglobin as a Predictor of the Length of Hospital Stay in Patients Following Coronary Bypass Graft Surgery in the Saudi Population

Objective

The diabetic population has a high prevalence of coronary artery disease, and frequently patients with diabetes undergo coronary artery bypass graft (CABG) surgery. Elevated glycated hemoglobin (HbA1c) in diabetics is shown to be associated with morbidity and mortality, but the association of HbA1c with postoperative length of hospital stay (LOS) has conflicting results. In this study, we aim to identify if elevated HbA1c levels are associated with prolonged LOS after CABG surgery.

Methods

A retrospective chart review study was performed, using a total of 305 patients who were referred for CABG surgery. HbA1c levels were measured before the day of surgery. Patients were classified into two groups according to HbA1c levels: <7% and ≥7%. A LOS of more than 14 days was proposed as an extended LOS. HbA1c and the LOS relationship were assessed using appropriate statistical methods.

Results

Patients who had diabetes mellitus comprised 81.6% of our studied population. Sixty-four percent had HbA1c levels ≥ 7%. There was no significant difference in the total LOS in HbA1c <7% compared to HbA1c ≥7% patients (P=0.367).

Conclusion

Our study results rejected the proposed hypothesis that elevated HbA1c levels ≥7% would be associated with prolonged hospital stay following CABG surgery in a Saudi population.

Intensity of Glycemic Control Affects Long-Term Survival After Coronary Artery Bypass Graft Surgery

BACKGROUND

A patient's hemoglobin (Hb) A_1c level, regardless of diabetic status, is a measure of glycemic control. Studies have found it is an independent predictor of short-term death in patients undergoing coronary artery bypass grafting (CABG). In this study, we used preoperative HbA_1c to assess whether levels are associated with short-term and long-term survival after CABG.

METHODS

From a regional registry of consecutive cases, we identified 6,415 patients undergoing on-pump isolated CABG from 2008 to 2015 with documented preoperative HbA_1c level. We defined four HbA_1c groups: less than 5.7% (n = 1,713), 5.7% to 6.4% (n = 2,505), 6.5% to 8.0% (n = 1,377), and more than 8% (n = 820). Relationship to in-hospital outcomes and long-term survival was assessed. Outcome rates and hazard ratios were adjusted for patient and disease risk factors using multivariable logistic regression and Cox models.

RESULTS

The study included 3,740 patients (58%) not diagnosed as having diabetes and 2,674 with diabetes. Prediabetes (HbA_1c 5.7% to 6.4%) was documented in 52% (n = 1,933) of nondiabetic patients. Higher HbA_1c values were associated with younger age, female sex, greater body mass index, more comorbid diseases, lower ejection fraction, more 3-vessel coronary disease, and recent myocardial infarction (p < 0.05 trend for all). After adjustment for patient risk, greater HbA_1c values were not associated with higher rates of in-hospital death or morbidity. Long-term survival was significantly worse as HbA_1c increased. Risk of death increased by 13% for every unit increase in HbA_1c (adjusted hazard ratio, 1.13; 95% confidence interval, 1.07 to 1.19; p < 0.001).

CONCLUSIONS

Preadmission glycemic control, as assessed by HbA_1c, is predictive of long-term survival, with higher levels associated with poorer prognosis. Whether this risk can be modified by better glycemic control postoperatively remains to be determined.

Association of Elevated Pre-operative Hemoglobin A1c and Post-operative Complications in Non-diabetic Patients: A Systematic Review

IMPORTANCE

Pre-operative hyperglycemia is associated with post-operative adverse outcomes in diabetic and non-diabetic patients. Current pre-operative screening includes random plasma glucose, yet plasma glycated hemoglobin (HbA1c) is a better measure of long-term glycemic control. It is not clear whether pre-operative HbA1c can identify non-diabetic patients at risk of post-operative complications.

OBJECTIVE

The systematic review summarizes the evidence pertaining to the association of suboptimal pre-operative HbA1c on post-operative outcomes in adult surgical patients with no history of diabetes mellitus.

EVIDENCE REVIEW

A detailed search strategy was developed by a librarian to identify all the relevant studies to date from the major online databases.

FINDINGS

Six observational studies met all the eligibility criteria and were included in the review. Four studies reported a significant association between pre-operative HbA1c levels and post-operative complications in non-diabetic patients. Two studies reported increased post-operative infection rates, and two reported no difference. Of four studies assessing the length of stay, three did not observe any association with HbA1c level and only one study observed a significant impact. Only one study found higher mortality rates in patients with suboptimal HbA1c.

CONCLUSIONS AND RELEVANCE

Based on the limited available evidence, suboptimal pre-operative HbA1c levels in patients with no prior history of diabetes predict post-operative complications and represent a potentially modifiable risk factor.

Utility of glycated hemoglobin screening in patients undergoing elective coronary artery surgery: Prospective, cohort study from the E-CABG registry

BACKGROUND

Patients with increased glycated hemoglobin (HbA1c) seem to be at increased risk of sternal wound infection (SWI) after coronary artery bypass grafting (CABG). However, it is unclear whether increased baseline HbA1c levels may affect other postoperative outcomes.

MATERIAL AND METHODS

Data on preoperative levels of HbA1c were collected from 2606 patients undergoing elective isolated CABG from 2015 to 2016 and included in the prospective, multicenter E-CABG registry.

RESULTS

The prevalence of HbA1c ≥ 53 mmol/mol (7.0%) among non-diabetics was 5.3%, among non-insulin dependent diabetics was 53.5% and among insulin dependent diabetics was 67.1% (p < 0.001). The prevalence of HbA1c > 75 mmol/mol (9.0%) among non-diabetics was 0.5%, among non-insulin dependent diabetics was 5.8% and among insulin dependent diabetics was 10.6% (p < 0.001). Baseline levels of HbA1c ≥ 53 mmol/mol (7.0%) was a significant predictor of any SWI (10.7% vs. 3.3%, adjusted p-value: <0.001), deep SWI/mediastinitis (3.8% vs. 1.3%, adjusted p-value: 0.001) and acute kidney injury (27.4% vs. 19.8%, adjusted p-value: 0.042). These findings were confirmed in multilevel mixed effect logistic regression adjusted for participating centers. Among patients with diabetes, HbA1c ≥ 53 mmol/mol (7.0%) was predictive of SWI (11.1% vs. 4.8%, p = 0.001).

CONCLUSIONS

HbA1c is increased in a significant proportion of patients undergoing elective CABG and these patients are at higher risk of SWI. Less clear is the impact of increased HbA1c on other postoperative outcomes. These results do not support screening of HbA1c in patients without history of diabetes. Preoperative screening of HbA1c is valuable only to identify diabetics at risk of SWI.

Effect of glycaemic control on complications following cardiac surgery: literature review

Introduction

No uniform consensus in the UK or Europe exists, for glycaemic management of patients with Diabetes or pre-diabetes undergoing cardiac surgery.

Objective

[i] Determine the relationship between glycaemic control and cardiac surgical outcomes; [ii] Compare current vs gold standard management of patients with Diabetes or pre-diabetes undergoing cardiac surgery.

Methods

Searches of MEDLINE, NHS Evidence and Web of Science databases were completed. Articles were limited to those in English, German and French. No date limit was enforced.13,232 articles were identified on initial literature review, and 50 relevant papers included in this review.

Results

No national standards for glycaemic control prior to cardiac surgery were identified. Upto 30% of cardiac surgical patients have undiagnosed Diabetes. Cardiac surgical patients without Diabetes with pre-operative hyperglycaemia have a 1 year mortality double that of patients with normoglyacemia, and equivalent to patients already diagnosed with Diabetes. Pre- and peri-operative hyperglycaemia is associated with worse outcomes. Evidence regarding tight glycaemic control vs moderate glycaemic control is conflicting. Tight control may be more effective in patients without Diabetes with pre−/peri-operative hyperglycaemia, and moderate control appears more effective in patients with pre-existing Diabetes. Patients with well controlled Diabetes may achieve comparable outcomes to patients without Diabetes with similar glycaemic control.

Conclusions

Pre / peri-operative hyperglycaemia is associated with worse outcomes in both patients with, and without Diabetes undergoing CABG. This review supports the pre-operative screening, and optimisation of glycaemic control in patients undergoing cardiac surgery. Optimal glycaemic management remains unclear and clear guidelines are needed.

Impact of elevated glycosylated hemoglobin on hospital outcome and 1 year survival of primary isolated coronary artery bypass grafting patients

Objective

It is unknown whether adequacy of diabetic control, measured by hemoglobin A1c, is a predictor of adverse outcomes after coronary artery bypass grafting.

Methods

From December 2013 to November 2015, 80 consecutive patients underwent primary isolated CABG surgery at national heart institute, their data were prospectively collected and they were classified according to their HbA1c level into two groups, Group (A): Forty patients with fair glycemic control (HbA1c below or equal to 7%), Group (B): Forty patients with poor glycemic control (HbA1c above 7%). Hospital morbidity, mortality and one year survival were examined in both groups. Telephone conversation was used to call patients or their relatives to determine the one year survival and it was 100% complete. This study had gained the ethical approval from national heart institute ethical committee.

Results

In-hospital mortality for group A was 2.5% (one patient) and 7.5% (3 patients) for group B with no statistical significance. One year mortality was (5.13%) (2 patients for group A) and (8.11%) (3 patients) for group B with no statistical significance. As regard the morbidity there was no statistical significance between the two groups in the incidence of neurological complications whether stroke or coma, atrial fibrillation, postoperative myocardial infarction, low cardiac output syndrome, heart failure, renal failure, need for dialysis, deep sternal wound infection, and readmission. However, group B had lengthy hospital stay, lengthy ventilation hours, more respiratory complications, and more superficial wound infection with a statistical significance when compared to group A, P values were 0.003, 0.003, 0.038, 0.044 respectively.

Conclusions

This study showed that HbA1c is a good predictor of in-hospital morbidity. It worth devoting time and effort to decrease HbA1c level below 7% to decrease possible postoperative complications.

Hemoglobin A1c Levels Predicts Acute Kidney Injury after Coronary Artery Bypass Surgery in Non-Diabetic Patients

INTRODUCTION:

Elevated hemoglobin A1c levels in patients with diabetes mellitus have been known as a risk factor for acute kidney injury after coronary artery bypass grafting. However, the relationship between hemoglobin A1c levels in non-diabetics and acute kidney injury is under debate. We aimed to investigate the association of preoperative hemoglobin A1c levels with acute kidney injury in non-diabetic patients undergoing isolated coronary artery bypass grafting.

METHODS:

202 non-diabetic patients with normal renal function (serum creatinine <1.4 mg/dl) who underwent isolated coronary bypass were analyzed. Hemoglobin A1c level was measured at the baseline examination. Patients were separated into two groups according to preoperative Hemoglobin A1c level. Group 1 consisted of patients with preoperative HbA1c levels of < 5.6% and Group 2 consisted of patients with preoperative HbA1c levels of ≥ 5.6%. Acute kidney injury diagnosis was made by comparing baseline and postoperative serum creatinine to determine the presence of predefined significant change based on the Kidney Disease Improving Global Outcomes (KDIGO) definition.

RESULTS:

Acute kidney injury occurred in 19 (10.5%) patients after surgery. The incidence of acute kidney injury was 3.6% in Group 1 and 16.7% in Group 2. Elevated baseline hemoglobin A1c level was found to be associated with acute kidney injury (P=0.0001). None of the patients became hemodialysis dependent. The cut off value for acute kidney injury in our group of patients was 5.75%.

CONCLUSION:

Our findings suggest that, in non-diabetics, elevated preoperative hemoglobin A1c level may be associated with acute kidney injury in patients undergoing coronary artery bypass grafting. Prospective randomized studies in larger groups are needed to confirm these results.

Impact of post-procedural hyperglycemia on acute kidney injury after transcatheter aortic valve implantation

BACKGROUND

Post-operative hyperglycemia, in individuals with and without diabetes, has been identified as a predictor of acute kidney injury (AKI) in patients following cardiac surgery. Whether or not this is also true for patients undergoing transcatheter aortic valve implantation (TAVI) is unknown.

OBJECTIVES

To evaluate whether post-procedural glucose levels are associated with AKI after TAVI.

METHODS AND RESULTS

A total of 422 consecutive patients undergoing transfemoral TAVI were included in the analysis. For each patient, plasma glucose levels were assessed at hospital admission, 4h after the procedure and daily during hospitalization. Post-procedural hyperglycemia was defined as 2 consecutive blood glucose readings ≥150mg/dL in the 72-hour period following TAVI. AKI was defined according to the VARC consensus report regarding standardized endpoint definitions. Overall, 137 (32.5%) patients developed post-procedural hyperglycemia and 138 (33%) patients developed AKI. Hyperglycemia was associated with a 2-fold higher incidence of AKI than in patients without hyperglycemia (48% vs. 25%, p<0.001). In-hospital mortality was higher in patients with hyperglycemia than in those without hyperglycemia (9.6% vs. 1.8%, p<0.001). In-hospital mortality rate was also higher in patients who developed AKI (12.7% vs. 2.7%, p<0.001). Patients with acute hyperglycemia that developed AKI had the highest in-hospital and long-term mortality rate (15% and 38%). Post-procedural hyperglycemia was an independent predictor of AKI.

CONCLUSIONS

Post-procedural hyperglycemia is associated with a higher incidence of AKI and mortality after TAVI. Randomized controlled trials are needed to determine whether meticulous post-procedural glycemic control following TAVI impacts upon clinical outcomes.

Prognostic significance of glycemic variability after cardiac surgery

INTRODUCTION

The prognostic significance of acute glycemic variability (GV) after cardiac surgery is not known. This study was therefore planned to analyze the independent prognostic value of GV after cardiac surgery.

MATERIALS AND METHODS

This is a single center prospective observational study in 870 consecutive cardiac surgery patients over a 3-month period at a tertiary care institute in India.

RESULTS

In linear regression analysis, GV was a significant predictor of length of stay in intensive care unit (LOS-ICU) (beta 0.102, p=0.007) and rise in creatinine after surgery (beta 0.229, p<0.001). Mean POC-BG was a significant positive predictor of length of stay in hospital (LOS-hospital) (beta 0.1, p=0.004). In multivariable logistic regression analysis, GV predicted prolonged LOS-ICU (p=0.006, OR 1.016) and acute kidney injury (p<0.001, OR 1.034).

CONCLUSION

This study showed that GV, as measured by standard deviation, was a predictor of LOS-ICU, rise in creatinine and AKI after cardiac surgery. GV is therefore a new dimension in postoperative glycemic management in cardiac surgery patients, which needs to be explored.

The Emory University Perioperative Algorithm for the Management of Hyperglycemia and Diabetes in Non-cardiac Surgery Patients

Hyperglycemia is a frequent manifestation of critical and surgical illness, resulting from the acute metabolic and hormonal changes associated with the response to injury and stress (Umpierrez and Kitabchi, Curr Opin Endocrinol. 11:75-81, 2004; McCowen et al., Crit Care Clin. 17(1):107-24, 2001). The exact prevalence of hospital hyperglycemia is not known, but observational studies have reported a prevalence of hyperglycemia ranging from 32 to 60 % in community hospitals (Umpierrez et al., J Clin Endocrinol Metab. 87(3):978-82, 2002; Cook et al., J Hosp Med. 4(9):E7-14, 2009; Farrokhi et al., Best Pract Res Clin Endocrinol Metab. 25(5):813-24, 2011), and 80 % of patients after cardiac surgery (Schmeltz et al., Diabetes Care 30(4):823-8, 2007; van den Berghe et al., N Engl J Med. 345(19):1359-67, 2001). Retrospective and randomized controlled trials in surgical populations have reported that hyperglycemia and diabetes are associated with increased length of stay, hospital complications, resource utilization, and mortality (Frisch et al., Diabetes Care 33(8):1783-8, 2010; Kwon et al., Ann Surg. 257(1):8-14, 2013; Bower et al., Surgery 147(5):670-5, 2010; Noordzij et al., Eur J Endocrinol. 156(1):137-42, 2007; Mraovic et al., J Arthroplasty 25(1):64-70, 2010). Substantial evidence indicates that correction of hyperglycemia reduces complications in critically ill, as well as in general surgery patients (Umpierrez et al., J Clin Endocrinol Metab. 87(3):978-82, 2002; Clement et al., Diabetes Care 27(2):553-97, 2004; Pomposelli et al., JPEN J Parented Enteral Nutr. 22(2):77-81, 1998). This manuscript reviews the pathophysiology of stress hyperglycemia during anesthesia and the perioperative period. We provide a practical outline for the diagnosis and management of preoperative, intraoperative, and postoperative care of patients with diabetes and hyperglycemia.

Hyperglycemia and Acute Kidney Injury During the Perioperative Period

Hyperglycemia and acute kidney injury (AKI) are frequently observed during the perioperative period. Substantial evidence indicates that hyperglycemia increases the prevalence of AKI as a surgical complication. Patients who develop hyperglycemia and AKI during the perioperative period are at significantly elevated risk for poor outcomes such as major adverse cardiac events and all-cause mortality. Early observational and interventional trials demonstrated that the use of intensive insulin therapy to achieve strict glycemic control resulted in remarkable reductions of AKI in surgical populations. However, more recent interventional trials and meta-analyses have produced contradictory evidence questioning the renal benefits of strict glycemic control. Although the exact mechanisms through which hyperglycemia increases the risk of AKI have not been elucidated, multiple pathophysiologic pathways have been proposed. Hypoglycemia and glycemic variability may also play a significant role in the development of AKI. In this literature review, the complex relationship between hyperglycemia and AKI as well as its impact on clinical outcomes during the perioperative period is explored.

Present-Day Hospital Readmissions after Left Ventricular Assist Device Implantation: A Large Single-Center Study

Left ventricular assist device (LVAD) therapy improves survival, hemodynamic status, and end-organ perfusion in patients with refractory advanced heart failure. Hospital readmission is an important measure of the intensity of LVAD support care. We analyzed readmissions of 148 patients (mean age, 53.6 ± 12.7 yr; 83% male) who received a HeartMate II LVAD from April 2008 through June 2012. The patients had severe heart failure; 60.1% were in Interagency Registry for Mechanically Assisted Circulatory Support class 1 or 2. All patients were observed for at least 12 months, and readmissions were classified as planned or unplanned. Descriptive and multivariate regression analyses were used to identify predictors of unplanned readmission. Twenty-seven patients (18.2%) had no readmissions or 69 planned readmissions, and 121 patients (81.8%) had 460 unplanned readmissions. The LVAD-related readmissions were for bleeding, thrombosis, and anticoagulation (n=103; 49.1%), pump-related infections (n=60; 28.6%), and neurologic events (n=28; 13.3%). The readmission rate was 2.1 per patient-year. Unplanned readmissions were for comorbidities and underlying cardiac disease (54.3%) or LVAD-related causes (45.7%). In the unplanned-readmission rate, there was no significant difference between bridge-to-transplantation and destination-therapy patients. Unplanned readmissions were associated with diabetes mellitus (odds ratio [OR]=3.3; P=0.04) and with shorter mileage from residence to hospital (OR=0.998; P=0.046). Unplanned admissions for LVAD-related sequelae and ongoing comorbidities were common. Diabetes mellitus and shorter distance from residence to hospital were significant predictors of readmission. We project that improved management of comorbidities and of anticoagulation therapy will reduce unplanned readmissions of LVAD patients in the future.

Relationship between development of urethral stricture after transurethral resection of prostate and glycemic control

Objectives:

The purpose of this study is to investigate the association of glycemic control prior to TUR-P and postoperative urethral stricture development.

Materials and Methods:

Of the 168 patients with a diagnosis of urethral stricture, who underwent internal urethrotomy in our hospital were retrospectively analyzed for this study.

98 patients who underwent monopolar TUR-P in our hospital previously and were developed urethral stricture were divided into two groups as diabetic and nondiabetic. Based on their HbA1c concentrations, diabetics were allocated to two groups with good (HbA1c ≤6.5%) or poor (HbA1c > 6,5%) glycemic control. Time to internal urethrotomy and the other operative parameters were compared among groups.

Results:

Time to internal urethrotomy after TUR-P was significantly shorter in diabetic patients with poor glycemic control than Group 1 and Group 2 (P = 0,02, P = 0,012) but no significant difference was found between Group 1 and Group 2 (P = 0,368). There was no significant difference in the mean diagnosed and resected prostate wight among groups There was no significant difference in the mean resection time and the mean time to urethral catheter removal among groups.

Conclusions:

Especially in poor glycemic control patients, urethral stricture development was seen in the early period after TUR-P. For this reason, in the elective TUR-P scheduled poor glycemic controlled patients the operation should be done after glycemic control.

Glycated hemoglobin HbA1c - a new risk marker for the outcome of cardiac surgery?

Introduction

About 30% of patients undergoing cardiac surgery are diabetic, and glycated hemoglobin (HbA_1c) is a reliable marker for long-term glucose control. The aim of our study was to examine whether tight glucose control before a cardiac operation results in a better outcome of the surgical treatment.

Material and methods

We performed a retrospective record review of 350 diabetic patients undergoing cardiac surgery in our institution. Preoperative glycemia control was assessed by measurement of the glycated hemoglobin level. The patient population was divided into three groups: group I – patients with HbA_1c below 7% (n = 195); group II – patients with HbA_1c between 7% and 8% (n = 88); and group III – patients with HbA_1c above 8% (n = 67).

Results

The demographic data and operating risk in all groups of patients were similar. There were 2 deaths (1.02%) in group I, 2 deaths (2.27%, p = 0.78) in group II and 3 deaths (4.47%, p = 0.20) in group III. Cardiac accidents occurred in 9 patients (4.60%) from group I, 7 patients (7.95%, p = 0.20) from group II, and in 6 patients (9.05%, p = 0.40) from group III. Cerebrovascular accidents (CVA) occurred in 7 (3.58%), 5 (5.68%, p = 0.67) and 5 (7.46%, p = 0.61) patients, respectively. Acute renal dysfunction requiring renal replacement therapy occurred in 4 patients from group I (2.05%), 3 patients from group II (3.40%, p = 0.78) and 4 patients from group III (5.97%, p = 0.23).

Conclusions

A large percentage of diabetic patients referred for cardiac operations have poorly controlled glycemia. Optimal preoperative glycemia control results in lower postoperative mortality and morbidity. In addition, the preoperative HbA_1c level is a good indicator of the risk of postoperative complications in diabetic patients undergoing cardiac operations.

What laboratory tests are required for ambulatory surgery?

Current recommendations from the 2002 ASA Task Force on Preanesthesia Evaluation are not specific to ambulatory surgery and are not based on strongly designed and adequately powered studies. Furthermore, although the ASA does not advocate routine testing or testing without indication, the guidelines for "selective" or "indicated" testing are unclear. As a result, preoperative testing in the United States is overused relative to the current ASA Task Force recommendations. Uncertainty regarding indications leads to wide variation in the use of preoperative testing across providers. There is evidence to suggest that current guidelines may recommend testing more than is necessary. Several studies reviewed in this article have shown that the elimination of routine testing and more selective use based on patient history and physical examination findings would decrease cost and increase patient satisfaction without detriment to patient care. Future studies should evaluate the effectiveness of testing in specific clinical situations, allowing for identification of clear conditions under which preoperative testing should be performed. This approach would allow the promulgation of clear guidelines, the development of which should involve surgeons (as members of a multidisciplinary team), anesthesiologists, and hospital administrators, together with governing bodies such as the ASA and American College of Surgeons that offer support for the dissemination and broad adoption of guidelines. In the future, studies should focus not only on identifying specific clinical situations whereby preoperative testing will be beneficial but also on determining current barriers to improving adherence to guidelines. Potential barriers include institutional policies for testing, physician reluctance to change practice, problems in communication between members involved in perioperative care, and legal consequences of not ordering preoperative tests. Identification of reasons for overuse of testing is the first step toward changing practice. Once clear guidelines are developed, the creation of preoperative clinics that centralize preoperative care, or promoting the use of clinical pathways and/or checklists for determining appropriate tests, may improve the adequate use of preoperative tests. It will be critical for quality improvement measures to include surgeons, anesthesiologists, hospital administrators, and governing bodies such as the ASA and American College of Surgeons to achieve success.

Elevated hemoglobin A1c is associated with readmission but not complications

Background

studies have shown that elevated hemoglobin A1c levels are associated with worse short-term outcomes after cardiac surgery. However, the effect on readmission has not been studied. The primary purpose of this study was to determine the independent effect of hemoglobin A1c level on the readmission rate after cardiac surgery. The secondary purpose was assess its effect on complications and mortality.

Methods

consecutive patients undergoing coronary artery bypass surgery between April 2007 and August 2010 were divided into 3 groups based on preoperative hemoglobin A1c levels. Outcomes were controlled for demographics, comorbidities, and surgery.

Results

300 (34%) patients had normal hemoglobin A1c levels (<6.0%), 305 (35%) had mildly elevated levels (6.0%–6.9%), and 275 (31%) had markedly elevated levels (≥7.0%). Postoperative glucose levels were similar among all 3 hemoglobin A1c groups. Compared to patients with normal hemoglobin A1c levels, those with higher levels were more likely to be readmitted: adjusted odds ratio 2.091 (95% confidence interval: 1.074–4.069, p = 0.036) for hemoglobin A1c 6.1%–6.9%; and adjusted odds ratio 2.089 (95% confidence interval: 1.050–4.155, p = 0.036) for hemoglobin A1c ≥ 7.0. Overall, 381 (43%) patients suffered complications, and hemoglobin A1c levels were similar in those with and without complications (6.8% ± 1.6% vs. 6.9% ± 1.7%, p = 0.837). Mortality was equivalent in all 3 hemoglobin A1c groups.

Conclusions

elevated preoperative hemoglobin A1c levels are associated with an increased risk of readmission but not complications.

Is there a role for HbA1c in predicting mortality and morbidity outcomes after coronary artery bypass graft surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was is there a role for HbA1c in predicting morbidity and mortality outcomes after coronary artery bypass surgery? Eleven studies presented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The studies presented analyse the relationship between preoperative HbA1c levels and postoperative outcomes following coronary artery bypass graft (CABG) in diabetic, non-diabetic or mixed patient groups. Four studies found significant increases in early and late mortality at higher HbA1c levels, regardless of a preoperative diagnosis of diabetes. One study demonstrated that 30-day survival outcomes were significantly worse in patients with previously undiagnosed diabetes and elevated HbA1c compared with those with good control [HbA1c >6%; odds ratio 1.53, confidence interval (CI) (1.24-1.91); P = 0.0005]. However, four studies of early mortality outcomes in diabetic patients only showed no significant differences between patients with normal and those with deranged HbA1c levels (P = 0.99). There were mixed reports on morbidity outcomes. Three studies identified a significant increase in infectious complications in patients with poorly controlled HbA1c, two of which were irrespective of previous diabetic status [deep sternal wound infection (P = 0.014); superficial sternal wound infection (P = 0.007) and minor infections (P = 0.006) in poorly controlled diabetics only]. Four studies presented outcomes for total length of stay (LOS). Three of these papers looked specifically at diabetic patients, of which two found no significant differences in length of stay between good and poor preoperative glycaemic control [LOS: P = 0.59 and 0.86 vs P < 0.001]. However, elevated HbA1c vs normal HbA1c was associated with prolonged stay in hospital and in intensive care unit (ICU) in patients irrespective of previous diabetic status [total LOS (P < 0.001)]. Elevated HbA1c levels were also a significant predictor of reduced intraoperative insulin sensitivity in diabetic patients (R = -0.527; P < 0.001). Furthermore, higher HbA1c levels were associated with a reduced incidence of postoperative atrial fibrillation (P = 0.001). We conclude that elevated HbA1c is a strong predictor of mortality and morbidity irrespective of previous diabetic status. In particular, the mortality risk for CABG is quadrupled at HbA1c levels >8.6%. Some studies have called into question the predictive value of HbA1c on short-term outcomes in well-controlled diabetics; however, long-term outcomes in this population have not been reported.

Preoperative hemoglobin A1c and postoperative glucose control in outcomes after gastric bypass for obesity

BACKGROUND

Hemoglobin A1c (HbA1c) is a reliable marker for long-term glycemic control in obese diabetic patients. Roux-en-Y gastric bypass improves HbA1c levels over time. However, it is not clear whether the preoperative HbA1c level is a predictor of the outcome in these patients. Our objectives were to understand the predictive capacity of the preoperative HbA1c level in gastric bypass patients at a single university-based Bariatric Center of Excellence.

METHODS

We performed a retrospective review of 468 charts from 2006 to 2009 of patients who had undergone Roux-en-Y gastric bypass. Using their preoperative HbA1c status, the patients were categorized and the postoperative outcomes compared.

RESULTS

Of the 468 patients reviewed, 310 (66.2%) had a HbA1c of <6.5% (group 1), 92 (19.4%) had a HbA1c of 6.5-7.9% (group 2), and 66 (14.1%) had a HbA1c level of >8.0% (group 3). No difference was found among the 3 groups in baseline body mass index, race, procedure type, length of stay, hospital cost, and smoking status. Groups 2 and 3 were associated with older age, male gender, and higher baseline creatinine. Groups 2 and 3 also had a proportionally greater inpatient postoperative blood glucose level. An elevated postoperative glucose level was independently associated with wound infection (P = .008) and acute renal failure (P = .04). Also, group 3 experienced worse outcomes, including less weight loss at 18 months and fewer diabetic remissions. Over time, however, the vast majority in all groups achieved excellent chronic glycemic control, with HbA1c <6.5% after Roux-en-Y gastric bypass.

CONCLUSION

Poor preoperative glycemic control is associated with worse glucose level control postoperatively, fewer diabetic remissions, and less weight loss. An elevated mean postoperative glucose level is independently associated with increased morbidity.

Preventing acute kidney injury after cardiac surgery

PURPOSE OF REVIEW

Acute kidney injury (AKI) is a serious complication that significantly increases morbidity, mortality and cost of care after cardiac surgery. In this review we identify the current literature that addresses strategies for renal protection and the prevention of AKI after cardiac surgery.

RECENT FINDINGS

Even with aggressive medical care and renal replacement therapy (RRT) the morbidity, mortality and cost of postoperative AKI after cardiac surgery is substantial. An emphasis on preventive strategies would therefore appear to be the most cost-effective approach. Recent literature offers hope that as our understanding of the pathogenesis of AKI after cardiac surgery continues to improve, new directions for the prevention and amelioration of AKI will emerge. Approaches to the prevention of postoperative AKI include careful risk stratification of patients, allowing adequate recovery following a prior AKI, consideration of less extensive surgical procedures, avoidance of cardiopulmonary bypass, minimizing injury from radiocontrast dyes or other nephrotoxic agents, and optimizing cardiovascular function and oxygen delivery. Early identification of AKI and prompt, judicious application of RRT may also improve outcomes. Interest in pharmacologic renoprotection is currently directed toward statins and sodium bicarbonate.

SUMMARY

Postoperative AKI is a serious complication after cardiac surgery. Therapeutic interventions and RRT have limited influence on the outcome of AKI, and a preventive strategy remains the mainstay to attenuate its impact.