The impact of diabetes mellitus on acute kidney injury after coronary artery bypass grafting

Risk Factors and Outcomes of Acute Kidney Injury After Cardiac Surgery: A Retrospective Observational Single-Center Study

Background

Acute kidney injury (AKI) following cardiac surgery is a well-described phenomenon, usually associated with hemodynamic changes ultimately leading to ischemic injury to the kidneys. In this study, we assessed the occurrence of AKI in a cohort of patients undergoing elective cardiac surgery at a single center.

Methods

Patients undergoing elective cardiac surgery (coronary artery bypass grafting (CABG) and/or valve repair) between the years 2016 and 2022 were retrospectively included in the study.

Results

During the study, 167 patients underwent CABG, valve replacement, or both procedures. The majority were male (85.0%). Post-operative AKI was observed in 27.5% of patients, with 2.4% requiring continuous renal replacement therapy (CRRT)/dialysis. The majority of AKI cases were staged as Kidney Disease: Improving Global Outcomes (KDIGO) stage 1. Among patients needing CRRT/dialysis, 1.8% recovered renal function within 3 months, with 0.6% experiencing 30-day mortality. In univariate analysis, factors associated with AKI included older age (P = 0.003), severe anemia (P < 0.0001), pre-operative creatinine elevation (P < 0.0001), complex surgeries (P < 0.0001), blood product transfusion (P < 0.0001), longer cross-clamp (XC) and cardiopulmonary bypass (CPB) times (P < 0.0001), and inotropes usage (P < 0.0001). Classical risk factors like diabetes mellitus (DM) and hypertension did not show significant differences. The majority of these factors (severe anemia, age, pre-operative creatinine, post-operative inotrope usage, and cross-clamp times) were consistently significant (P < 0.05) in logistic regression analysis.

Conclusion

Post-operative AKI following cardiac surgery is frequent, with significant associations seen especially with pre-operative anemia. Future investigations focusing on the specific causes of anemia linked to AKI development are essential, considering the high prevalence of hemoglobinopathy traits in our population.

Perioperative Left Ventricular Assist Device Use in Patients With Reduced Ejection Fraction Reduces Cardiac Surgery-Associated Acute Kidney Injury

Background Cardiac surgery may precipitate acute kidney injury (AKI), particularly in patients with poor baseline cardiac function. This is thought to be due to intraoperative renal hypoperfusion, which results in increased morbidity and mortality. This study evaluated the perioperative use of the Impella LD (Abiomed, Danvers, MA) left ventricular assist device (LVAD) in the prevention of postoperative AKI in patients with reduced left ventricular ejection fraction (LVEF) undergoing cardiac surgery. Methods A retrospective analysis was performed at Northwest Medical Center, Tucson, AZ, USA, on patients undergoing valve surgery, coronary artery bypass grafting (CABG), or both by a single surgeon. Those with preoperative LVEF ≤35% and preoperative serum creatinine ≥1 mg/dL were included and segregated based on intraoperative LVAD implantation. Postoperative renal function was assessed using serum creatinine levels and KDIGO (Kidney Disease Improving Global Outcomes) criteria to define AKI. Results Twenty-three patients were enrolled. There were no significant differences in age, demographics, baseline characteristics, or comorbidities between the treatment (n = 12) and the control group (n = 11). In the treatment group, 8% developed AKI by POD#7, while 64% of controls did. The treatment group had a significantly lower mean creatinine change from POD#0-7 (0.07 vs. 0.59, p = 0.02). However, there was no significant difference between groups in the mean creatinine change from baseline to discharge (0.46 vs. 0.42, p = 0.47). Conclusions Our study suggests that intraoperative Impella implantation may reduce the incidence of early postoperative AKI. LVAD implantation is an approach to increase and ensure adequate end-organ (renal) perfusion and can improve postoperative recovery without dialysis requirements. Additional studies are required to understand its protective effects during the perioperative period fully.

Acute kidney injury in diabetes mellitus: Epidemiology, diagnostic, and therapeutic concepts

Acute kidney injury (AKI) and diabetes mellitus (DM) are public health problems that cause a high socioeconomic burden worldwide. In recent years, the landscape of AKI etiology has shifted: Emerging evidence has demonstrated that DM is an independent risk factor for the onset of AKI, while an alternative perspective considers AKI as a bona fide complication of DM. Therefore, it is necessary to systematically characterize the features of AKI in DM. In this review, we summarized the epidemiology of AKI in DM. While focusing on circulation- and tissue-specific microenvironment changes after DM, we described the active cellular and molecular mechanisms of increased kidney susceptibility to AKI under DM stress. We also reviewed the current diagnostic and therapeutic strategies for AKI in DM recommended in the clinic. Updated recognition of the epidemiology, pathophysiology, diagnosis, and medications of AKI in DM is believed to reveal a path to mitigate the frequency of AKI and DM comorbidity that will ultimately improve the quality of life in DM patients.

Type 2 diabetes mellitus and In-hospital Major Adverse Cardiac and Cerebrovascular Events (MACCEs) and postoperative complications among patients undergoing on-pump isolated coronary artery bypass surgery in Northeastern Iran

BACKGROUND

Diabetes Mellitus (DM) is a rapidly growing disorder worldwide, especially in the Middle East. A higher incidence of coronary artery diseases requiring coronary artery bypass graft (CABG) surgery has been reported in patients with diabetes. We assessed the association between type 2 diabetes mellitus (T2DM) and in-hospital major adverse cardiac and cerebrovascular events (MACCEs) and postoperative complications among patients who underwent on-pump isolated CABG.

METHODS

In this retrospective cohort study, we used the data registered for CABG patients from two heart centers in the Golestan province (North of Iran) between 2007 and 2016. The study population included 1956 patients divided into two groups: 1062 non-diabetic patients and 894 patients with diabetes (fasting plasma glucose ≥126 mg/dl or using antidiabetic medications). The study outcome was in-hospital MACCEs, a composite outcome of myocardial infarction (MI), stroke and cardiovascular death, and postoperative complications, including postoperative arrhythmia, acute atrial fibrillation (AF), major bleeding (defined as reoperation due to bleeding), and acute kidney injury (AKI).

RESULTS

During the 10-year study period, 1956 adult patients with a mean (SD) age of 59.0 (9.60) years were included. After adjustment for age, gender, ethnicity, obesity, opium consumption, and smoking, diabetes was a predictor of postoperative arrhythmia (AOR 1.30, 95% CI 1.08-1.57; P = 0.006). While it was not a predictor of in-hospital MACCEs (AOR 1.35, 95% CI 0.86, 2.11; P = 0.188), AF (AOR 0.85, 95% CI 0.60-1.19; P = 0.340), major bleeding (AOR 0.80, 95% CI 0.50, 1.30; P = 0.636) or AKI (AOR 1.29, 95% CI 0.42, 3.96; P 0.656) after CABG surgery.

CONCLUSION

Findings indicated that diabetes increased the risk of postoperative arrhythmia by 30%. However, we found similar in-hospital MACCEs, acute AF, major bleeding, and AKI following CABG surgery in both diabetic and non-diabetic patients.

Microvascular dysfunction following cardiopulmonary bypass plays a central role in postoperative organ dysfunction

Despite significant advances in surgical technique and strategies for tissue/organ protection, cardiac surgery involving cardiopulmonary bypass is a profound stressor on the human body and is associated with numerous intraoperative and postoperative collateral effects across different tissues and organ systems. Of note, cardiopulmonary bypass has been shown to induce significant alterations in microvascular reactivity. This involves altered myogenic tone, altered microvascular responsiveness to many endogenous vasoactive agonists, and generalized endothelial dysfunction across multiple vascular beds. This review begins with a survey of in vitro studies that examine the cellular mechanisms of microvascular dysfunction following cardiac surgery involving cardiopulmonary bypass, with a focus on endothelial activation, weakened barrier integrity, altered cell surface receptor expression, and changes in the balance between vasoconstrictive and vasodilatory mediators. Microvascular dysfunction in turn influences postoperative organ dysfunction in complex, poorly understood ways. Hence the second part of this review will highlight in vivo studies examining the effects of cardiac surgery on critical organ systems, notably the heart, brain, renal system, and skin/peripheral tissue vasculature. Clinical implications and possible areas for intervention will be discussed throughout the review.

Clinical outcomes of off-pump coronary artery bypass graft in patients with diabetes and non-diabetics: A systematic review and meta-analysis

BACKGROUND AND AIM

Diabetes mellitus is a prevalent risk factor for developing coronary artery disease which worsens the clinical outcomes of patients undergoing coronary artery bypass grafting (CABG). This study aimed to determine the clinical outcomes of patients with diabetes and non-diabetic patients who underwent off-pump CABG surgery.

METHOD

Medline, Scopus, Proquest, Embase, Web of Science, and Google scholar were searched until September 10, 2021. The effect sizes including unstandardized mean difference and odds ratio with 95% confidence interval were calculated using "Metan" package. The Cochran's Q-test and I² statistic were used to assess heterogeneity, a random-effects model was applied to estimate the pooled effect sizes, and meta-regression was used to investigate the factors affecting heterogeneity between studies.

RESULTS

10 studies with 6200 sample sizes were included in the study. In groups with diabetes, Summary odds ratio (SOR) and 95% confidence interval of infection was 2.18 more than non-diabetic groups. Also, odds renal complication was 1.74 more than non-diabetic groups, and the odds cardiovascular complication in groups with diabetes was 1.30 more than non-diabetics. There were no differences in mortality, neurologic, respiratory and surgical complications between groups with diabetes and non-diabetics. Based on meta-regression results, age (Coefficient: 0.942; p = 0.009) had a significant direct relationship and sample size (Coefficient: 0.001; p = 0.009) had an indirect significant relationship with heterogeneity of neurologic outcomes. There was no significant publication bias in our results.

CONCLUSION

Our study revealed that off-pump CABG led to some significant outcomes in patients with diabetes compared to non-diabetics. Renal and infection complications were higher in patients with diabetes but no significant differences were seen in most of other postoperative outcomes between the two groups.

Age, body mass index, and diabetes mellitus are associated with an increased risk of acute kidney injury after coronary surgery: Retrospective cohort study

Background/Aim: Cardiac surgery-associated acute kidney injury (CSA-AKI) is a significant complication of cardiac surgery and is associated with increased morbidity and mortality. Identifying risk factors can help clinicians alleviate the risk of developing CSA-AKI and associated complications. Therefore, this study aimed to identify pre-operative patient-related risk factors of CSA-AKI in patients undergoing coronary surgery. Methods: The current study was a single-center retrospective cohort study of adult patients undergoing coronary surgery with cardiopulmonary bypass (CPB) over an 8-month period. AKI was scored according to The Kidney Disease Improving Global Outcomes (KDIGO) scoring system. Patients’ age, gender, body mass index (BMI), comorbidities, KDIGO staging in AKI patients, and 30-day mortality rates were recorded. These variables were compared between AKI(−) and AKI (+) groups. Univariate binary regression analysis was performed between the variables that had statistically significant differences and AKI. Results: A total of 248 coronary surgery patients were analyzed. The overall incidence of CSA-AKI was 16.5%. Age, BMI, and the proportion of diabetic patients were significantly higher in the AKI (+) group (P = 0.04, P < 0.001, and P = 0.022, respectively). The proportion of gender, chronic obstructive pulmonary disease (COPD), hypertension (HT), baseline creatinine levels, aortic cross-clamping, cardiopulmonary bypass (CPB), total operation duration, and 30-day mortality were similar between the groups. Univariate analysis demonstrated that CSA-AKI was significantly associated with age ³ 65 years (odds ratio [OR] = 2.506; confidence interval [CI]: 1.265–4.967; P = 0.008), BMI of ³ 25 kg m-2 (OR = 8.994; CI: 1.199–67.980; P = 0.033), and diabetes mellitus (OR = 2.171; CI: 1.103–4.273; P = 0.025). Conclusion: The current study revealed that patients with increased age, BMI, and DM had a higher incidence of CSA-AKI. Therefore, even though these patient-related variables are known as non-modifiable parameters, more attention should be paid to preventing CSA-AKI during peri-operative management of these patients.