Perioperative outcomes and risk assessment in dialysis patients: current knowledge and future directions

Rule-based clinician-developed programmes can facilitate haemodialysis clinical workflows

There are routine hospital workflows that are not addressed by certain institutional electronic medical records, including the detection of patients requiring haemodialysis who are admitted under non-nephrology services. In this study, the feasibility and performance of a clinician-developed automated haemodialysis patient finder was evaluated. The programme ran with zero downtime for 6 months and had zero false negatives or false positives. This work demonstrates the potential benefits that may be gained when clinicians can meaningfully alter electronic clinical workflows.

Revised cardiac risk index in predicting cardiovascular complications in patients receiving chronic kidney replacement therapy undergoing elective general surgery

INTRODUCTION

The Revised Cardiac Risk Index (RCRI) is a six-parameter model that is commonly used in assessing individual 30-day perioperative cardiovascular risk before general surgery, but its use in patients on chronic kidney replacement therapy (KRT) is unvalidated. This study aimed to externally validate RCRI in this patient group over a 15-year period.

METHODS

Data linkage was used between the the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry and jurisdictional hospital admisisons data across Australia and New Zealand to identify all incident and prevalent patients on chronic KRT between 2000 and 2015 who underwent elective abdominal surgery. Chronic KRT was categorised as haemodialysis (HD), peritoneal dialysis (PD), home haemodialysis (HHD) and kidney transplant. The outcome of interest was major adverse cardiovascular event (MACE) which was defined as nonfatal myocardial infarction, nonfatal stroke, non-fatal cardiac arrest and cardiovascular mortality at 30 days. Logistic regression was used with the RCRI score included as a continuous variable to estimate discrimination by area under the receiver operating curve (AUROC). Calibration was evaluated using a calibration plot. Clinical utility was assessed using a decision curve analysis to determine the net benefit.

RESULTS

A total of 5094 elective surgeries were undertaken, and MACE occurred in 153 individuals (3.0%). Overall, RCRI had poor discrimination in patients on chronic KRT undergoing elective surgery (AUROC 0.67), particularly in patients aged greater than 65 years (AUROC 0.591). A calibration plot showed that RCRI overestimated risk of MACE. The expected-to-observed outcome ratio was 6.0, 5.1 and 2.5 for those with RCRI scores of 1, 2 and ≥ 3, respectively. Discrimination was moderate in patients under 65 years and in kidney transplant recipients, with AUROC values of 0.740 and 0.718, respectively. Overestimation was common but less so for kidney transplant recipients. Decision curve analysis showed that there was no net benefit of using the tool in neither the overall cohort nor patients under 65 years, but a slight benefit associated with threshold probability > 5.5% in kidney transplant recipients.

CONCLUSIONS

The RCRI tool performed poorly and overestimated risk in patients on chronic dialysis, potentially misinforming patients and clinicians about the risk of elective surgery. Further research is needed to define a more comprehensive means of estimating risk in this unique population.

Postoperative Outcomes After Gastrointestinal Surgery in Patients Receiving Chronic Kidney Replacement Therapy: A Population-based Cohort Study

OBJECTIVE

This study evaluated the postoperative mortality and morbidity outcomes following the different subtypes of gastrointestinal (GI) surgery over a 15-year period.

BACKGROUND

Patients receiving chronic kidney replacement therapy (KRT) experience higher rates of general surgery compared with other surgery types. Contemporary data on the types of surgeries and their outcomes are lacking. KRT was defined as patients requiring chronic dialysis (hemodialysis or peritoneal dilaysis) or having a functioning kidney transplant long-term.

METHODS

All incident and prevalent patients aged greater than 18 years identified in the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry as receiving chronic KRT were linked with jurisdictional hospital admission datasets between January 1, 2000 until December 31, 2015. Patients were categorized by their KRT modality [hemodialysis (HD), peritoneal dialysis (PD), home hemodialysis (HHD), and kidney transplant (KT)]. GI surgeries were categorized as upper gastrointestinal (UGI), bowel (small and large bowel), anorectal, hernia surgery, cholecystectomy, and appendicectomy. The primary outcome was the rates of the different surgeries, estimated using Poisson models. Secondary outcomes were risks of 30-day/in-hospital postoperative mortality risk and nonfatal outcomes and were estimated using logistic regression. Independent predictors of 30-day mortality were examined using comorbidity-adjusted Cox models.

RESULTS

Overall, 46,779 patients on chronic KRT were linked to jurisdictional hospital datasets, and 9,116 patients were identified as having undergone 14,540 GI surgeries with a combined follow-up of 76,593 years. Patients on PD had the highest rates of GI surgery (8 per 100 patient years), with hernia surgery being the most frequent. Patients on PD also had the highest risk of 30-day postoperative mortality following the different types of GI surgery, with the risk being more than 2-fold higher after emergency surgery compared with elective procedures. Infective postoperative complications were more common than cardiac complications. This study also observed a U-shaped association between body mass index (BMI) and mortality, with a nadir in the 30 to 35 kg/m 2 group.

CONCLUSIONS

Patients on chronic KRT have high rates of GI surgery and morbidity, particularly in those who receive PD, are older, or are either underweight or moderately obese.

Postoperative outcomes, predictors and trends of mortality and morbidity in patients undergoing hip fracture surgery with underlying aortic stenosis: a nationwide inpatient sample analysis

BACKGROUND

Hip fractures frequently necessitate hospitalization, especially among patients aged 75 and above who might concurrently suffer from aortic stenosis (AS). This study focuses on postoperative outcomes, potential determinants of morbidity and mortality, as well as evolving trends in patients with AS undergoing surgical repair of hip fractures.

METHODS

A retrospective analysis of the Nationwide Inpatient Sample from 2008 to 2019 was conducted. Hip fracture cases were identified, and a subgroup with AS was isolated using the ICD-9 and ICD-10 diagnostic codes. We compared baseline characteristics, postoperative in-hospital outcomes and trends in mortality and morbidity between patients with and without AS.

RESULTS

From the dataset, 2,834,919 patients with hip fracture were identified on weighted analysis. Of these, 94,270 (3.3%) were found to have concurrent AS. The AS cohort was characterized by higher mean age and elevated burden of cardiovascular comorbidities, such as coronary artery disease, peripheral vascular disease, pulmonary hypertension, congestive heart failure and cardiac arrhythmias. Postoperative mortality following hip fracture surgery was greater in the AS groups compared to non-AS group (3.3% vs 1.57%, p < 0.001). Risk factors such as congestive heart failure (OR, 2.3[CI, 2.1-2.6]), age above 85 years (OR, 3.2[CI, 2.2-4.7]), cardiac arrhythmias (OR, 2.4[CI, 2.2-2.6]), end-stage renal disease (OR, 3.4[CI, 2.7-4.1]), malnutrition (OR, 2.3[CI, 2.1-2.7]) and AS (OR, 1.2[CI, 1.08-1.5] were associated with increased adjusted odds of postoperative mortality. AS was linked to higher adjusted odds of postoperative mortality (OR, 1.2 [CI, 1.1-1.5]) and complications such as acute myocardial infarction (OR, 1.2 [CI, 1.01-1.4]), cardiogenic shock (OR, 2.0[CI, 1.4-2.9]) and acute renal failure (OR, 1.1[CI, 1.02-1.2]). While hospital stay duration was comparable in both groups (average 5 days), the AS group incurred higher costs (mean $50,673 vs $44,607). The presence of acute heart failure in patients with AS and hip fracture significantly increased mortality, hospital stay, and cost. A notable decline in postoperative in-hospital mortality was observed in both groups from 2008-2019 though the rate of major in-hospital complications rose.

CONCLUSION

AS significantly influences postoperative in-hospital mortality and complication rates in hip fracture patients. While a reduction in postoperative mortality was observed in both AS and non-AS cohorts, the incidence of major in-hospital complications increased across both groups.

Long-term impact of early non-infectious complications at the initiation of peritoneal dialysis

BACKGROUND

Early non-infectious complications at initiation of peritoneal dialysis (PD) are a major burden with unknown long-term impacts on individuals.

METHODS

Prospective multicentre cohort study using univariable and multivariable Cox regression to identity mortality risk and PD discontinuation risk in those with and without non-infectious complications. All individuals commencing PD between 1 January 2014 and 31 December 2018, registered in the New Zealand Peritoneal Dialysis Registry (NZPDR) were followed up to 31 December 2020. Early non-infectious complications defined as functional, catheter-related, exit-site dialysate leak or anatomical leak complications occurring within 30 days of initiation of PD. Primary outcomes were patient survival and time on PD therapy. Secondary outcomes were peritonitis free survival, first PD catheter survival and catheter tunnel infection free survival.

RESULTS

Of 1596 individuals included in the study, 102 experienced an early non-infectious complication. Multivariable analysis demonstrated these complications were associated with higher risk of overall mortality (hazard ratio (HR) 1.71; 95% confidence interval (CI) 1.21-2.44), PD discontinuation (HR 1.84; 95% CI 1.41-2.41) and first catheter failure (HR 2.89; 95% CI 2.28-3.66). No difference was found for risk of development of first peritonitis episode or catheter tunnel infection. Mortality risk was associated with functional and exit-site dialysate leak complications and continued beyond 180 days. Risk of PD discontinuation and first catheter loss were associated with catheter and functional complications in the first 180 days.

CONCLUSION

Early non-infectious complications are associated with long-term mortality risk. Further research in risk factors and causes of early non-infectious complications are required.

Application of Propofol Target-Controlled Infusion for Optimized Hemodynamic Status in ESRD Patients Receiving Arteriovenous Access Surgery: A Randomized Controlled Trial

Background and Objectives: End-stage renal disease (ESRD) is associated with increased anesthetic risks such as cardiovascular events resulting in higher perioperative mortality rates. This study investigated the perioperative and postoperative outcomes in ESRD patients receiving propofol target-controlled infusion with brachial plexus block during arteriovenous (AV) access surgery. Materials and Methods: We recruited fifty consecutive patients scheduled to receive AV access surgery. While all patients received general anesthesia combined with ultrasound-guided brachial plexus block, the patients were randomly assigned to one of two general anesthesia maintenance groups, with 23 receiving propofol target-controlled infusion (TCI) and 24 receiving sevoflurane inhalation. We measured perioperative mean arterial pressure (MAP), heart rate, and cardiac output and recorded postoperative pain status and adverse events in both groups. Results: ESRD patients receiving propofol TCI had significantly less reduction in blood pressure than those receiving sevoflurane inhalation (p < 0.05) during AV access surgery. Perioperative cardiac output and heart rate were similar in both groups. Both groups reported relatively low postoperative pain score and a low incidence of adverse events. Conclusions: Propofol TCI with brachial plexus block can be used as an effective anesthesia regimen for ESRD patients receiving AV access surgery. It can be used with less blood pressure fluctuation than inhalational anesthesia.

Cause of postoperative mortality in patients with end-stage renal disease

Background: The number of patients with end-stage renal disease (ESRD) who are dependent on hemodialysis is increasing rapidly. As a result, more patients with ESRD need surgery. These patients have a significantly higher risk of postoperative death than those with normal kidney function. Therefore, this study analyzed the causes of postoperative mortality in ESRD patients undergoing surgery under general anesthesia and the risk factors for postoperative mortality.Methods: This retrospective analysis examined the mortality of ESRD patients, 20 to 80 years old, undergoing surgery under general anesthesia. We excluded patients who underwent cardiac, cancer, or emergency surgery or organ transplantation from the analysis. The primary outcome was the cause of postoperative 30-day mortality in ESRD patients. We also assessed the mortality rate and risk factors.Results: There were 2,459 eligible ESRD patients. When patients underwent multiple surgeries during the study period, only the last surgery was considered. In total, 167 patients died during the study period, including 65 within 30 days postoperatively. The cause of death was sepsis in 22 cases (33.8%) and a major cardiac event in 16 (24.6%). Atrial fibrillation, current angina, previous myocardial infarction, asthma, lower hemoglobin and albumin levels, and a larger intraoperative colloid volume were likely to increase mortality. Conclusions: Our study suggests that immunological issues have a significant role in the death of ESRD patients after general anesthesia.

Morbidity after elective surgery in patients on chronic dialysis: a systematic review and meta-analysis

BACKGROUND

Patients on chronic dialysis are at increased risk of postoperative mortality following elective surgery compared to patients with normal kidney function, but morbidity outcomes are less often reported. This study ascertains the excess odds of postoperative cardiovascular and infection related morbidity outcomes for patients on chronic dialysis.

METHODS

Systematic searches were performed using MEDLINE, Embase and the Cochrane Library to identify relevant studies published from inception to January 2020. Eligible studies reported postoperative morbidity outcomes in chronic dialysis and non-dialysis patients undergoing major non-transplant surgery. Risk of bias was assessed using the Newcastle-Ottawa Scale and the certainty of evidence was summarised using GRADE. Random effects meta-analyses were performed to derive summary odds estimates. Meta-regression and sensitivity analyses were performed to explore heterogeneity.

RESULTS

Forty-nine studies involving 10,513,934 patients with normal kidney function and 43,092 patients receiving chronic dialysis were included. Patients on chronic dialysis had increased unadjusted odds of postoperative cardiovascular and infectious complications within each surgical discipline. However, the excess odds of cardiovascular complications was attenuated when odds ratios were adjusted for age and comorbidities; myocardial infarction (general surgery, OR 1.83 95% 1.29-2.36) and stroke (general surgery, OR 0.95, 95%CI 0.84-1.06). The excess odds of infectious complications remained substantially higher for patients on chronic dialysis, particularly sepsis (general surgery, OR 2.42, 95%CI 2.12-2.72).

CONCLUSION

Patients on chronic dialysis are at increased odds of both cardiovascular and infectious complications following elective surgery, with the excess odds of cardiovascular complications attributable to being on dialysis being highest among younger patients without comorbidities. However, further research is needed to better inform perioperative risk assessment.

Postoperative outcomes of kidney transplant recipients undergoing non-transplant-related elective surgery: a systematic review and meta-analysis

Background

Reliable estimates of the absolute and relative risks of postoperative complications in kidney transplant recipients undergoing elective surgery are needed to inform clinical practice. This systematic review and meta-analysis aimed to estimate the odds of both fatal and non-fatal postoperative outcomes in kidney transplant recipients following elective surgery compared to non-transplanted patients.

Methods

Systematic searches were performed through Embase and MEDLINE databases to identify relevant studies from inception to January 2020. Risk of bias was assessed by the Newcastle Ottawa Scale and quality of evidence was summarised in accordance with GRADE methodology (grading of recommendations, assessment, development and evaluation). Random effects meta-analysis was performed to derive summary risk estimates of outcomes. Meta-regression and sensitivity analyses were performed to explore heterogeneity.

Results

Fourteen studies involving 14,427 kidney transplant patients were eligible for inclusion. Kidney transplant recipients had increased odds of postoperative mortality; cardiac surgery (OR 2.2, 95%CI 1.9–2.5), general surgery (OR 2.2, 95% CI 1.3–4.0) compared to non-transplanted patients. The magnitude of the mortality odds was increased in the presence of diabetes mellitus. Acute kidney injury was the most frequently reported non-fatal complication whereby kidney transplant recipients had increased odds compared to their non-transplanted counterparts. The odds for acute kidney injury was highest following orthopaedic surgery (OR 15.3, 95% CI 3.9–59.4). However, there was no difference in the odds of stroke and pneumonia.

Conclusion

Kidney transplant recipients are at increased odds for postoperative mortality and acute kidney injury following elective surgery. This review also highlights the urgent need for further studies to better inform perioperative risk assessment to assist in planning perioperative care.

Postoperative mortality in patients on chronic dialysis following elective surgery: A systematic review and meta-analysis

RATIONALE & OBJECTIVE

The prognostic significance of dialysis-dependent end-stage kidney disease on postoperative mortality is unclear. This study aims to estimate the odds of postoperative mortality in patients receiving chronic dialysis undergoing elective surgery compared to patients with normal kidney function, and to examine the influence of comorbidities on the excess mortality risk.

METHODS

A systematic search of studies published up to January 2020 was conducted using MEDLINE, EMBASE and CENTRAL databases. Eligible studies reported postoperative 30-day or in-hospital mortality in chronic dialysis patients compared to patients with normal kidney function undergoing elective surgery. Two investigators independently reviewed all abstracts and performed risk of bias assessments using the Newcastle-Ottawa Scale. Quality of evidence was summarised in accordance with GRADE methodology (grading of recommendations, assessment, development and evaluation). Relative mortality risk estimates were obtained using random effects meta-analysis. Heterogeneity was explored using meta-regression. (PROSPERO CRD42017076565).

RESULTS

Forty-nine studies involving 41, 822 chronic dialysis and 10, 476, 321 non-dialysis patients undergoing elective surgery were included. Patients on chronic dialysis had a greatly increased postoperative mortality odds compared to patients with normal kidney function. The excess risk ranged from OR 10.8 (95%CI 7.3-15.9) following orthopaedic surgery to OR 4.0 (95%CI 3.2-4.9) after vascular surgery. Adjustment for age and comorbidity attenuated the excess odds but remained higher for patients on chronic dialysis, irrespective of surgical discipline. Meta-regression analysis demonstrated an inverse linear relationship between excess mortality risk and study-level mean age (slope -0.06; P = 0.001) and diabetes prevalence (slope -0.02; p = 0.001).

CONCLUSIONS

Patients on chronic dialysis have an increased odds for postoperative mortality following elective surgery across all surgical disciplines. This relationship is consistent among all studies, with the excess postoperative mortality attributable to end-stage kidney disease and chronic dialysis treatment may be lower among older patients with diabetes.