Metabolic syndrome is an independent risk factor for stroke and acute renal failure after coronary artery bypass grafting

Metabolic syndrome and surgical complications: a systematic review and meta-analysis of 13 million individuals

BACKGROUND

Metabolic syndrome (MetS) is characterised by the presence of at least three of the five following components: insulin resistance, obesity, chronic hypertension, elevated serum triglycerides, and decreased high-density lipoprotein cholesterol concentrations. It is estimated to affect 1 in 3 people around the globe and is reported to affect 46% of surgical patients. For people with MetS who undergo surgery, an emerging body of literature points to significantly poorer postoperative outcomes compared with nonaffected populations. The aim of this study is to review the current evidence on the risks of surgical complications in patients with MetS compared to those without MetS.

METHODS

Systematic review and meta-analysis using PRISMA and AMSTAR reporting guidelines.

RESULTS

The meta-analysis included 63 studies involving 1 919 347 patients with MetS and 11 248 114 patients without MetS. Compared to individuals without the condition, individuals with MetS were at an increased risk of mortality (OR 1.75 95% CI: 1.36-2.24; P <0.01); all surgical site infection types as well as dehiscence (OR 1.64 95% CI: 1.52-1.77; P <0.01); cardiovascular complications (OR 1.56 95% CI: 1.41-1.73; P <0.01) including myocardial infarction, stroke, cardiac arrest, cardiac arrythmias and deep vein thrombosis; increased length of hospital stay (MD 0.65 95% CI: 0.39-0.9; P <0.01); and hospital readmission (OR 1.55 95% CI: 1.41-1.71; P <0.01).

CONCLUSION

MetS is associated with a significantly increased risk of surgical complications including mortality, surgical site infection, cardiovascular complications, increased length of stay, and hospital readmission. Despite these risks and the high prevalence of MetS in surgical populations there is a lack of evidence on interventions for reducing surgical complications in patients with MetS. The authors suggest prioritising interventions across the surgical continuum that include (1) preoperative screening for MetS; (2) surgical prehabilitation; (3) intraoperative monitoring and management; and (4) postoperative rehabilitation and follow-up.

Risk factors for development of acute renal failure in 5077 coronary artery bypass grafting patients in the current era

BACKGROUND

Acute renal failure (ARF) is one of the major complications after coronary artery bypass grafting (CABG) surgery. The risk factors are changing along with the technical evolution. The aim of this study was to identify the risk factors for ARF requiring dialysis after CABG surgery in the current era.

METHODS

Between April 2012 and November 2019, 5077 consecutive patients who underwent CABG were analyzed retrospectively. The patients were divided into ARF group and non-ARF group according to whether ARF occurred and dialysis was required after operation. Univariate analysis was performed to find possible factors associated with ARF. Any variables that had trends to be associated with ARF were included in stepwise multiple logistic regression analysis.

RESULTS

Of the 5077 patients who underwent CABG, 53 (1.04%) developed ARF requiring dialysis whereas 5024 (98.96%) were in non-ARF group. Cardiopulmonary bypass (CPB) time (odds ratio [OR], 1.009; 95% confidence interval [CI], 1.003-1.016; p = .006), insertion of intra-aortic balloon pump (IABP; OR, 19.294; 95% CI, 5.49-67.808; p = .000), and low ejection fraction (EF; OR, 0.943; 95% CI, 0.894-0.994; p = .030) were independent risk factors for development of ARF requiring dialysis in patients undergoing CABG surgery.

CONCLUSION

Our study identified prolonged CPB time, insertion of IABP, and low EF as independent risk factors for developing ARF requiring dialysis after CABG. The results suggest that shortening of CPB time and protection of cardiac function are important factors to prevent ARF and that special care should be taken to protect the renal function when the patient need insertion of IABP.

The Metabolic Syndrome Paradox: Increased Morbidity and Decreased Mortality in Operative Orthopedic Trauma

We examined the impact of metabolic syndrome (MetS) on operative outcomes with orthopedic trauma, particularly among patients with pelvic, acetabular, and lower extremity fractures. This retrospective cohort study used the American College of Surgeons National Surgical Quality Improvement Program database to identify patients who had operative pelvic, acetabular, and lower extremity trauma from 2006 through 2014. We defined MetS as type 2 diabetes, a history of hypertension requiring medication, and body mass index of 30 kg/m² or greater. Patients with MetS were compared with unaffected patients and assessed for association with in-hospital complications and mortality. The study population included 37,495 patients; 5.7% (n=2154) had MetS. On multivariable logistic regression, MetS was associated with increased odds of any hospital complication (odds ratio [OR], 1.30; 95% CI, 1.13-1.51; P<.001), Clavien-Dindo grade IV complications (OR, 1.51; 95% CI, 1.23-1.87; P<.001), readmission (OR, 1.39; 95% CI, 1.18-1.63; P<.001), and reoperation (OR, 1.40; 95% CI, 1.11-1.76; P=.004). Conversely, MetS significantly decreased the odds of mortality (OR, 0.67; 95% CI, 0.49-0.92; P=.01). Although MetS is a risk factor for postoperative complications, longer length of stay, and increased readmission after surgical intervention for orthopedic lower extremity trauma, MetS appears to decrease the odds of mortality in this specific patient population, which merits further investigation. [Orthopedics. 2022;45(2):103-108.].

Relationship between metabolic syndrome and hypercapnia among obese patients with sleep apnea

BACKGROUND

In the obese patient population, some patients have severe obstructive sleep apnea (OSA) with daytime hypoventilation. Such patients are generally identified on the basis of the presence or absence of daytime hypercapnia, and the condition is called obesity hypoventilation syndrome. However, mechanisms for such daytime hypoventilation remain unclear.

AIM

To investigate metabolic syndrome and daytime hypercapnia association based on hypercapnia prevalence in obese OSA patients in a nested case-control study.

METHODS

Consecutive obese patients (body mass index ≥ 30 kg/m²) who underwent polysomnography due to suspected OSA were included. Among them, patients with severe OSA (apnea hypopnea index ≥ 30/h) were divided into two groups according to the presence or absence of hypercapnia during wakefulness (arterial partial pressure of carbon dioxide ≥ or < 45 Torr, respectively). The characteristics and clinical features of these two groups were compared.

RESULTS

Among 97 eligible patients, 25 patients (25.8%) had daytime hypercapnia. There were no significant differences in age, gender, body mass index, apnea-hypopnea index, and Epworth Sleepiness Scale scores between the two groups. However, patients with hypercapnia had a significantly lower arterial partial pressure of oxygen level (75.8 ± 8.2 torr vs 79.9 ± 8.7 torr, P = 0.042) and higher arterial partial pressure of carbon dioxide level (46.6 ± 2.5 torr vs 41.0 ± 2.9 torr, P < 0.001). Additionally, patients with hypercapnia were more likely to have metabolic syndrome (72.0% vs 48.6%, P = 0.043) and a higher metabolic score (the number of satisfied criteria of metabolic syndrome). In multivariate logistic regression analysis, the presence of metabolic syndrome was associated with the presence of hypercapnia (OR = 2.85, 95%CI: 1.04-7.84, P = 0.042).

CONCLUSION

Among obese patients with severe OSA, 26% of patients had hypercapnia during wakefulness. The presence of metabolic syndrome was independently correlated with the presence of daytime hypercapnia.

Sex and the Risk of AKI Following Cardio-thoracic Surgery: A Meta-Analysis

BACKGROUND AND OBJECTIVES

Being a woman is a well established risk factor for the development of cardiothoracic surgery-associated AKI. In striking contrast, women are less likely to develop AKI associated with noncardiac surgical procedures than men. In an attempt to ascertain why being a woman might be protective for ischemic AKI after general surgery but deleterious in patients undergoing cardiothoracic surgery, we examined cardiothoracic surgery-associated AKI in greater detail.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a systematic review and meta-analysis of cardiothoracic surgery-associated AKI studies published between January of 1978 and December of 2015 to further explore the relationship between sex and cardiothoracic surgery-associated AKI.

RESULTS

Sixty-four studies were identified that provided sex-specific data regarding the incidence of cardiothoracic surgery-associated AKI among 1,057,412 subjects. Using univariate analysis, women were more likely than men to develop AKI postoperatively (odds ratio, 1.21; 95% confidence interval, 1.09 to 1.33; P<0.001). However, when the analysis was restricted to the 120,464 subjects reported in 29 studies that used the Acute Kidney Injury Network criteria, the RIFLE criteria, or the Kidney Disease Improving Global Outcomes criteria to define AKI, there was no significant sex-related difference in risk. Seventeen studies used multivariate analysis to assess risk factors for cardiothoracic surgery-associated AKI and provided sex-specific odd ratios. Among the 1,587,181 individuals included in these studies, the risk of developing cardiothoracic surgery-associated AKI was not significantly associated with sex (odds ratio, 1.04; 95% confidence interval, 0.92 to 1.19; P=0.51). However, when the analysis was restricted to the 5106 subjects reported in four studies that used the Acute Kidney Injury Network criteria to define AKI, the risk of developing AKI was significantly lower in women compared with in men (odds ratio, 0.75; 95% confidence interval, 0.65 to 0.87; P<0.001).

CONCLUSIONS

Our systematic review and meta-analysis contradict the generally held consensus that being a woman is an independent risk factor for the development of cardiothoracic surgery-associated AKI.

The effects of the metabolic syndrome on coronary artery bypass grafting surgery

Background

The metabolic syndrome (MS) is a clustering of factors that are associated with increased cardiovascular risk. A low-grade inflammatory process acts as the underlying pathophysiology, which suggests that the MS may have a detrimental effect on coronary interventions, including coronary artery bypass grafting (CABG) surgery performed with cardiopulmonary bypass (CPB). We aimed to evaluate the effect of the MS on morbidity and mortality rates in the early postoperative period in patients undergoing CABG.

Methods

We prospectively included 152 patients (109 males and 43 females; mean age 60.1 ± 8.6 years) who underwent elective CABG on CPB between January and September 2011. Early postoperative morbidity and mortality rates were compared between subjects with and without the MS. Diagnosis of the MS was based on the American National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria.

Results

Of the study group, 64 patients (42%) had the MS. The two groups were similar in age and gender. In the postoperative period, rates of atrial fibrillation, wound infection, pulmonary complications, and lengths of intubation, hospitalisation and intensive care unit stay were significantly higher in MS patients (p < 0.01). The MS was significantly associated with wound infection (OR 6.64, 95% CI: 1.72–25.75), pulmonary complications (OR 6.44, 95% CI: 1.58–26.33), arrhythmia (OR 5.47, 95% CI: 1.50–19.97) and prolonged intubation (OR 1.17, 95% CI: 1.05–1.32). The mortality rate was 3.1% in the MS group and 1.1% in the non-MS group, with no significant difference (p > 0.05).

Conclusion

The MS was associated with a higher rate of early postoperative morbidity following CABG, without having a significant effect on the mortality rate.

Exaggerated Acute Lung Injury and Impaired Antibacterial Defenses During Staphylococcus aureus Infection in Rats with the Metabolic Syndrome

Rats with Metabolic Syndrome (MetaS) have a dysregulated immune response to the aseptic trauma of surgery. We hypothesized that rats with MetaS would have dysregulated inflammation, increased lung injury, and less effective antibacterial defenses during Staphylococcus (S.) aureus sepsis as compared to rats without MetaS. Low capacity runner (LCR; a model of MetaS) and high capacity runner (HCR) rats were challenged intravenously with S. aureus bacteria. After 48 h, inflammatory mediators and bacteria were quantified in the blood, bronchoalveolar lavage fluid (BALF), and lung homogenates. Lungs were analyzed histologically. BALF protein and lung wet-dry ratios were quantified to assess for vascular leak. Endpoints were compared in infected LCR vs HCR rats. LCR rats had higher blood and lung S. aureus counts, as well as higher levels of IL-6 in plasma, lungs and BALF, MIP-2 in plasma and lung, and IL-17A in lungs. Conversely, LCR rats had lower levels of IL-10 in plasma and lungs. Although lactate levels, and liver and renal function tests were similar between groups, LCR rats had higher BALF protein and lung wet-dry ratios, and more pronounced acute lung injury histologically. During S. aureus bacteremia, as compared with HCR rats, LCR (MetaS) rats have heightened pro-inflammatory responses, accompanied by increased acute lung injury and vascular leak. Notably, despite an augmented pro-inflammatory phenotype, LCR rats have higher bacterial levels in their blood and lungs. The MetaS state may exacerbate lung injury and vascular leak by attenuating the inflammation-resolving response, and by weakening antimicrobial defenses.

Effects of metabolic syndrome with or without obesity on outcomes after coronary artery bypass graft. A cohort and 5-year study

BACKGROUND

Metabolic syndrome (MetS) and obesity are risk factors for cardiovascular disease, however, it remains unclear about effects of MetS with or without obesity on perioperative and long-term morbidity and mortality after coronary artery bypass graft (CABG).

METHODS

An observational cohort study was performed on 4,916 consecutive patients receiving isolated primary CABG in Fuwai hospital. Of all patients, 1238 patients met the inclusion criteria and were divided into three groups: control, MetS with obesity and MetS without obesity (n = 868, 76 and 294 respectively). The patient's 5-year survival and major adverse cerebral and cardiovascular events (MACCE) were studied.

RESULTS

Among all three groups, there were no significant differences in in-hospital postoperative complications, epinephrine use, stroke, ICU stay, ventilation time, atrial fibrillation, renal failure, coma, myocardial infarction, repeated revascularization, and long-term stroke. The patients in MetS without obesity group were not associated with increased perioperative or long-term morbidities and mortality. In contrast, the patients in MetS with obesity group were associated with significant increased perioperative complications including MACCE (30.26% vs. 20.75%, 16.7%, p = 0.0074) and mortality (11.84% vs. 3.74%, 3.11%, p = 0.0007) respectively. Patients in MetS with obesity group was associated with significantly increased long-term of MACCE (adjusted OR:2.040; 95%CI:1.196-3.481; P＜0.05) and 5-years of mortality (adjusted HR:4.659; 95%CI:1.966-11.042; P＜0.05).

CONCLUSIONS

Patients with metabolic syndrome and obesity are associated with significant increased perioperative and long-term complications and mortality, while metabolic syndrome without obesity do not worsen outcomes after CABG.

Impact of metabolic syndrome on mortality and morbidity after coronary artery bypass grafting surgery

Background:

The prevalence of Metabolic syndrome (MetS) has been increased in Asian countries. It represents a cluster of cardiovascular risk factors including obesity, insulin resistance, lipid abnormality and hypertension.

Objectives:

The purpose of this study was to assess the association between MetS and outcome in patients undergoing coronary artery bypass grafting surgery (CABG).

Patients and Methods:

This prospective study was performed on patients scheduled for coronary artery bypass grafting surgery (CABG). All the patients were followed up in hospital and three months afterward. Patients were excluded if they were younger than 18 years or had severe comorbidities, a history of valvular heart disease, and low ejection fraction.

Results:

A total of 235 patients (135 women) with a mean age of 59 ± 9.3 years were included. MetS was more prevalent in women (P < 0.001). The most prevalent complications were bleeding [20 (8.5%)] and dysrhythmia [18 (7.7%)]. At three months follow-up, the frequency rates of readmission [24 (10.2%)] and mediastinitis [9 (3.8%)] were higher than other complications. Diabetes and MetS were risk factors for a long ICU stay (> 5 days) and atelectasia (P < 0.05). Significant associations were observed between diabetes and pulmonary embolism (P = 0.025) and mediastinitis (P = 0.051).

Conclusions:

Identification of MetS before CABG can predict the surgery outcome. Patients with MetS have increased risks for longer ICU stay and atelectasia.

Surgery results in exaggerated and persistent cognitive decline in a rat model of the Metabolic Syndrome

BACKGROUND

Postoperative cognitive decline can be reproduced in animal models. In a well-validated rat model of the Metabolic Syndrome, we sought to investigate whether surgery induced a more severe and persistent form of cognitive decline similar to that noted in preliminary clinical studies.

METHODS

In rats that had been selectively bred for low and high exercise endurance, the low capacity runners (LCR) exhibited features of Metabolic Syndrome (obesity, dyslipidemia, insulin resistance, and hypertension). Tibial fracture surgery was performed under isoflurane anesthesia in LCR and high capacity runner (HCR) rats and cognitive function was assessed postoperatively in a trace-fear conditioning paradigm and Morris Water Maze; non-operated rats were exposed to anesthesia and analgesia (sham). Group sizes were n = 6.

RESULTS

On postoperative D7, LCR rats had shorter freezing times than postoperative HCR rats. Five months postoperatively, LCR rats had a flatter learning trajectory and took longer to locate the submerged platform than postoperative HCR rats; dwell-time in the target quadrant in a probe trial was shorter in the postoperative LCR compared to HCR rats. LCR and HCR sham rats did not differ in any test.

CONCLUSION

Postoperatively, LCR rats diverged from HCR rats exhibiting a greater decline in memory, acutely, with persistent learning and memory decline, remotely; this could not be attributed to changes in locomotor or swimming performance. This Metabolic Syndrome animal model of surgery-induced cognitive decline corroborates, with high fidelity, preliminary findings of postoperative cognitive dysfunction in Metabolic Syndrome patients.

Patients with uncontrolled components of metabolic syndrome have increased risk of complications following total joint arthroplasty

Metabolic syndrome (MetS)-a diagnostic grouping of diabetes, dyslipidemia, hypertension, and obesity-has been indicated as a risk factor for perioperative complications following total joint arthroplasty (TJA). This study investigates the impact of MetS on perioperative complications, specifically the importance of controlling MetS components. One hundred thirty-three patients undergoing TJA with all four components of MetS were identified. They were matched one-to-one with patients without MetS. Control of diabetes, dyslipidemia, and hypertension was assessed. Thirty-five patients with MetS were found to have at least a single uncontrolled component. The complication rates were 49%, 8%, and 8% for uncontrolled MetS, controlled MetS, and no MetS, respectively. Multivariate analysis confirmed independent associations between control of MetS components and both perioperative complications and length of stay. Both surgeons and patients should be aware of the substantial risk of dangerous complications following TJA in patients with uncontrolled metabolic syndrome.

Obesity in anesthesia and intensive care

Obesity is a global epidemic increasingly affecting management of anesthesia as well as intensive care medicine. Possible improvements in therapy require consideration of the specific pathophysiology of the obese, their concomitant diseases, and the complications associated with morbid obesity. Systematic assessment of perioperative risk factors is essential for an appropriate management. Paradoxically, overweight and moderately obese patients undergoing surgery have a lower risk when compared to patients with normal weight. The highest mortality and morbidity rates in this setting are reported for underweight and morbidly obese patients. The better chance of survival when compared to normal-weight individuals in the perioperative setting has been described the obesity paradox. In particular, the commitment of all involved physicians to improve all aspects of care will reduce the perioperative risk in obese patients. Physiological and pharmacological characteristics of the obese should also be considered. Furthermore, adequate technical equipment and practical skills of all members of the anesthesia team significantly contribute to risk reduction and therapeutic success in obese patients.

The effect of the metabolic syndrome on the risk and outcome of coronary artery bypass graft surgery

Background

The individual components of the metabolic syndrome are risk factors for coronary artery disease. The underlying pathophysiology of a low-grade inflammatory process postulates that the metabolic syndrome could compromise a procedure such as coronary artery bypass graft surgery (CABG) done on cardiopulmonary bypass (CPB).

Methods

From a single institution, 370 patients with the metabolic syndrome (IDF and ATP III criteria) and 503 patients without the metabolic syndrome were identified. The influence of the metabolic syndrome on the pre-operative core risk factors for CABG mortality as well as its effect on the mortality and major morbidity post surgery were investigated.

Results

Patients with the metabolic syndrome were operated on less urgently than those without the metabolic syndrome. The EuroSCORE was also lower in those with the metabolic syndrome. Patients with the metabolic syndrome required fewer units of homologous red blood cells, but stayed statistically longer in hospital.

Conclusions

In this surgical population the metabolic syndrome had no detrimental clinical effect on either the pre-operative risk factors or the outcome after CABG.

The neuroinflammatory response of postoperative cognitive decline

BACKGROUND

Aseptic surgical trauma provokes a homeostatic neuroinflammatory response to promote healing and protect the organism from further injury. When this response is dysregulated, harmful consequences can follow, including postoperative cognitive decline.

SOURCES OF DATA

We performed a comprehensive search on PubMed related to postoperative cognitive dysfunction (POCD).

AREAS OF AGREEMENT

Although the precise pathogenic mechanisms for POCD remain unclear, certain risk factors are known.

AREAS OF CONTROVERSY

The mechanisms that lead to exaggerated and persistent neuroinflammation and the best way to counteract it are still unknown. AREAS FOR DEVELOPING RESEARCH: It is imperative that we identify the underlying processes that increase the risk of cognitive decline in elderly surgical patients. In this review we explore non-resolution of inflammation as an underlying cause of developing exaggerated and persistent POCD. If interventions can be developed to promote resolution of neuroinflammation, the patient's postoperative recovery will be enhanced and long-term consequences can be prevented.