Meta-analysis of AKI to CKD transition in perioperative patients

The Impact of Acute Kidney Injury on Chronic Kidney Disease After Cardiac Surgery: A Systematic Review and Meta-analysis

OBJECTIVES

To evaluate the impact of acute kidney injury on transition to chronic kidney disease (CKD) after cardiac surgery and to determine frequency of incident CKD in these patients.

DESIGN

A systematic review and meta-analysis of observational studies.

SETTING

Electronic databases Medline and Embase were systematically searched from 1974 to February 6, 2023.

PARTICIPANTS

Eligible studies were original observational studies on adult cardiac surgery patients, written in the English language, and with clear kidney disease definitions. Exclusion criteria were studies with previously transplanted populations, populations with preoperative kidney impairment, ventricular assist device procedures, endovascular procedures, a kidney follow-up period of <90 days, and studies not presenting necessary data for effect size calculations.

INTERVENTIONS

Patients developing postoperative acute kidney injury after cardiac surgery were compared with patients who did not develop acute kidney injury.

MEASUREMENTS AND MAIN RESULTS

The search identified 4,329 unique studies, 87 underwent full-text review, and 12 were included for analysis. Mean acute kidney injury occurrence across studies was 16% (minimum-maximum: 8-50), while mean occurrence of CKD was 24% (minimum-maximum: 3-35), with high variability depending on definitions and follow-up time. Acute kidney injury was associated with increased odds of CKD in all individual studies. The pooled odds ratio across studies was 5.67 (95% confidence interval, 3.34-9.64; p < 0.0001).

CONCLUSIONS

Acute kidney injury after cardiac surgery was associated with a more than 5-fold increased odds of developing CKD. New-onset CKD occurred in almost 1 in 4 patients in the years after surgery.

Epithelial cell states associated with kidney and allograft injury

The kidney epithelium, with its intricate arrangement of highly specialized cell types, constitutes the functional core of the organ. Loss of kidney epithelium is linked to the loss of functional nephrons and a subsequent decline in kidney function. In kidney transplantation, epithelial injury signatures observed during post-transplantation surveillance are strong predictors of adverse kidney allograft outcomes. However, epithelial injury is currently neither monitored clinically nor addressed therapeutically after kidney transplantation. Several factors can contribute to allograft epithelial injury, including allograft rejection, drug toxicity, recurrent infections and postrenal obstruction. The injury mechanisms that underlie allograft injury overlap partially with those associated with acute kidney injury (AKI) and chronic kidney disease (CKD) in the native kidney. Studies using advanced transcriptomic analyses of single cells from kidney or urine have identified a role for kidney injury-induced epithelial cell states in exacerbating and sustaining damage in AKI and CKD. These epithelial cell states and their associated expression signatures are also observed in transplanted kidney allografts, suggesting that the identification and characterization of transcriptomic epithelial cell states in kidney allografts may have potential clinical implications for diagnosis and therapy.

Advanced chronic kidney disease after surgery and the contribution of acute kidney disease: a national observational cohort study

BACKGROUND

Limited knowledge exists regarding long-term renal outcomes after noncardiac surgery. This study investigated the incidence of, and risk factors for, developing advanced chronic kidney disease (CKD) and major adverse kidney events within 1 yr of surgery in a nationwide cohort.

METHODS

Adults without renal dysfunction before noncardiac surgery in Sweden were included between 2007 and 2013 in this observational multicentre cohort study. We analysed data from a national surgical database linked to several national and quality outcome registries. Associations of perioperative risk factors with advanced CKD (estimated glomerular filtration rate [eGFR] <30 ml min-1 1.73 m-2) and major adverse kidney events within 1 yr (MAKE365, comprising eGFR <30 ml min-1 1.73 m-2, chronic dialysis, death) were quantified.

RESULTS

Of 237,124 patients, 1597 (0.67%) developed advanced CKD and 16,789 (7.1%) developed MAKE365. Risk factors for advanced CKD included higher ASA physical status, urological surgery, extended surgical duration, prolonged postoperative hospital stay, repeated surgery, and postoperative use of renin-angiotensin-aldosterone system blockers. Advanced acute kidney disease (AKD) (eGFR <30 ml min-1 1.73 m-2 within 90 postoperative days) occurred in 1661 (0.70%) patients and was associated with advanced CKD (subdistribution hazard ratio [SHR] 44.5, 95% confidence interval [CI] 38.7-51.1) and MAKE365 (hazard ratio [HR] 6.60, 95% CI 6.07-7.17). Among patients with advanced AKD after surgery 36% developed advanced CKD at 1 yr after surgery and 51% developed MAKE365.

CONCLUSIONS

Advanced CKD within 1 yr after surgery is uncommon but clinically important in patients without preoperative renal dysfunction. Advanced AKD after surgery constitutes a major risk factor for advanced CKD and MAKE365.

Acute kidney injury after out-of-hospital cardiac arrest

BACKGROUND

Acute kidney injury (AKI) is a significant risk factor associated with reduced survival following out-of-hospital cardiac arrest (OHCA). Whether the severity of AKI simply serves as a surrogate measure of worse peri-arrest conditions, or represents an additional risk to long-term survival remains unclear.

METHODS

This is a sub-study derived from a randomized trial in which 789 comatose adult OHCA patients with presumed cardiac cause and sustained return of spontaneous circulation (ROSC) were enrolled. Patients without prior dialysis dependent kidney disease and surviving at least 48 h were included (N = 759). AKI was defined by the kidney disease: improving global outcome (KDIGO) classification, and patients were divided into groups based on the development of AKI and the need for continuous kidney replacement therapy (CKRT), thus establishing three groups of patients-No AKI, AKI no CKRT, and AKI CKRT. Primary outcome was overall survival within 365 days after OHCA according to AKI group. Adjusted Cox proportional hazard models were used to assess overall survival within 365 days according to the three groups.

RESULTS

In the whole population, median age was 64 (54-73) years, 80% male, 90% of patients presented with shockable rhythm, and time to ROSC was median 18 (12-26) min. A total of 254 (33.5%) patients developed AKI according to the KDIGO definition, with 77 requiring CKRT and 177 without need for CKRT. AKI CKRT patients had longer time-to-ROSC and worse metabolic derangement at hospital admission. Overall survival within 365 days from OHCA decreased with the severity of kidney injury. Adjusted Cox regression analysis found that AKI, both with and without CKRT, was significantly associated with reduced overall survival up until 365 days, with comparable hazard ratios relative to no AKI (HR 1.75, 95% CI 1.13-2.70 vs. HR 1.76, 95% CI 1.30-2.39).

CONCLUSIONS

In comatose patients who had been resuscitated after OHCA, patients developing AKI, with or without initiation of CKRT, had a worse 1-year overall survival compared to non-AKI patients. This association remains statistically significant after adjusting for other peri-arrest risk factors.

TRIAL REGISTRATION

The BOX trial is registered at ClinicalTrials.gov: NCT03141099.

Cardiac surgery-Associated acute kidney injury - A narrative review

Cardiac Surgery-Associated Acute Kidney Injury (CSA-AKI) is a serious complication seen in approximately 20-30% of cardiac surgery patients. The underlying pathophysiology is complex, often involving both patient- and procedure related risk factors. In contrast to AKI occurring after other types of major surgery, the use of cardiopulmonary bypass comprises both additional advantages and challenges, including non-pulsatile flow, targeted blood flow and pressure as well as the ability to manipulate central venous pressure (congestion). With an increasing focus on the impact of CSA-AKI on both short and long-term mortality, early identification and management of high-risk patients for CSA-AKI has evolved. The present narrative review gives an up-to-date summary on definition, diagnosis, underlying pathophysiology, monitoring and implications of CSA-AKI, including potential preventive interventions. The review will provide the reader with an in-depth understanding of how to identify, support and provide a more personalized and tailored perioperative management to avoid development of CSA-AKI.

Long-term disease interactions amongst surgical patients: a population cohort study

BACKGROUND

The average age of the surgical population continues to increase, as does prevalence of long-term diseases. However, outcomes amongst multi-morbid surgical patients are not well described.

METHODS

We included adults undergoing non-obstetric surgical procedures in the English National Health Service between January 2010 and December 2015. Patients could be included multiple times in sequential 90-day procedure spells. Multi-morbidity was defined as presence of two or more long-term diseases identified using a modified Charlson comorbidity index. The primary outcome was 90-day postoperative death. Secondary outcomes included emergency hospital readmission within 90 days. We calculated age- and sex-adjusted odds ratios (OR) with 95% confidence intervals (CI) using logistic regression. We compared the outcomes associated with different disease combinations.

RESULTS

We identified 20 193 659 procedure spells among 13 062 715 individuals aged 57 (standard deviation 19) yr. Multi-morbidity was present among 2 577 049 (12.8%) spells with 195 965 deaths (7.6%), compared with 17 616 610 (88.2%) spells without multi-morbidity with 163 529 deaths (0.9%). Multi-morbidity was present in 1 902 859/16 946 808 (11.2%) elective spells, with 57 663 deaths (2.7%, OR 4.9 [95% CI: 4.9-4.9]), and 674 190/3 246 851 (20.7%) non-elective spells, with 138 302 deaths (20.5%, OR 3.0 [95% CI: 3.0-3.1]). Emergency readmission followed 547 399 (22.0%) spells with multi-morbidity compared with 1 255 526 (7.2%) without. Multi-morbid patients accounted for 57 663/114 783 (50.2%) deaths after elective spells, and 138 302/244 711 (56.5%) after non-elective spells. The rate of death varied five-fold from lowest to highest risk disease pairs.

CONCLUSION

One in eight patients undergoing surgery have multi-morbidity, accounting for more than half of all postoperative deaths. Disease interactions amongst multi-morbid patients is an important determinant of patient outcome.

Driving role of macrophages in transition from acute kidney injury to chronic kidney disease

Acute kidney injury (AKI), characterized by acute renal dysfunction, is an increasingly common clinical problem and an important risk factor in the subsequent development of chronic kidney disease (CKD). Regardless of the initial insults, the progression of CKD after AKI involves multiple types of cells, including renal resident cells and immune cells such as macrophages. Recently, the involvements of macrophages in AKI-to-CKD transition have garnered significant attention. Furthermore, substantial progress has also been made in elucidating the pathophysiological functions of macrophages from the acute kidney to repair or fibrosis. In this review, we highlight current knowledge regarding the roles and mechanisms of macrophage activation and phenotypic polarization, and transdifferentiation in the development of AKI-to-CKD transition. In addition, the potential of macrophage-based therapy for preventing AKI-to-CKD transition is also discussed.