Renal tubular injury during cardiopulmonary bypass as assessed by urinary release of N-acetyl-ß-D-glucosaminidase

Risk factors for prolonged postoperative ICU stay in the patients with Stanford type A aortic dissection

OBJECTIVE

To investigate the independent risk factors for postoperative prolonged ICU stay in patients with Stanford type A aortic dissection (TAAD) and assess the clinical outcomes of prolonged ICU stay.

METHOD

The clinical data of 100 patients with TAAD admitted to the Department of Cardiovascular Surgery, First Affiliated Hospital of Anhui Medical University from December 2018 to September 2022 were retrospectively collected and analyzed. Patients were divided into two groups, based on the postoperative ICU stay (7 days as the threshold), regular ICU stay group (< 7 days) and prolonged ICU stay group (≥ 7 days). First, preoperative and intraoperative materials were collected for univariate analysis. Then, the significant variables after univariate analysis were analyzed using logistic regression, and the final independent risk factors for prolonged ICU stay were determined. Meanwhile, the postoperative clinical outcomes were analyzed with the aim of assessing the clinical outcomes due to prolonged ICU stay.

RESULTS

There were 65 and 35 patients in the regular ICU stay group and the prolonged ICU stay group, respectively. In accordance with the result of univariate analysis in the two groups, emergency surgery (χ2 = 13.598; P < 0.001), preoperative urea nitrogen (t = 3.006; P = 0.004), cardiopulmonary bypass (CPB) time (t = 2.671; P = 0.001) and surgery time (t = 2.630; P = 0.010) were significant. All significant variates were analyzed through logistic regression, and it was found that emergency surgery (OR = 0.192; 95% CI: 0.065-0.561), preoperative urea nitrogen (OR = 0.775; 95% CI: 0.634-0.947) and cardiopulmonary time (OR = 0.988; 95% CI: 0.979-0.998) were independent risk factors for prolonged postoperative ICU stay. The Receiver Operating Characteristic (ROC) curves of these three factors were also effective in predicting postoperative prolonged ICU stay (Emergency surgery, AUC = 0.308, 95% CI: 0.201-0.415; Preoperative urea nitrogen, AUC = 0.288, 95% CI: 0.185-0.392; cardiopulmonary time, AUC = 0.340, 95% CI: 0.223-0.457). Moreover, compared with a single factor, the predictive value of combined factors was more significant (AUC = 0.810, 95% CI: 0.722-0.897). For the comparison of postoperative data in the two groups,, compared with the regular ICU stay group, the incidence of adverse events in the prolonged ICU stay group increased significantly, including limb disability of limbs (χ2 = 22.182; P < 0.001), severe organ injury (χ2 = 23.077; P < 0.001), tracheotomy (χ2 = 17.582; P < 0.001), reintubation (χ2 = 28.020; P < 0.001), 72 h tracheal extubation after surgery (χ2 = 29.335; P < 0.001), 12 h consciousness recovery after surgery (χ2 = 18.445; P < 0.001), ICU re-entering (χ2 = 9.496; P = 0.002) and irregular discharging (χ2 = 24.969; P < 0.001).

CONCLUSION

Emergency surgery, preoperative urea nitrogen, and CPB time are risk factors for postoperative prolonged ICU stay after TAAD surgery. Furthermore, prolonged ICU stay is associated with worse clinical outcomes. Hence, a reasonable strategy should be adopted proactively focusing on the risk factors to shorten ICU stays and improve clinical outcomes.

Maternal protein deficiency alters primary cilia length in renal tubular and impairs kidney development in fetal rat

Introduction

Intrauterine malnutrition impairs embryo kidney development and leads to kidney disease and hypertension in adulthood, yet the underlying mechanism remains unclear.

Methods

With a maternal protein restriction (MPR) rat model, we investigated the critical ciliogenesis factors and β-catenin pathway in FGR fetal kidneys and analyzed the impact of aberrant primary cilia on renal tubular epithelium.

Results

The data showed decreased nephron number and renal tubular dysgenesis in FGR fetus. FGR fetus showed deregulated expression of ciliogenesis factors including upregulation of IFT88 and downregulation of DYNLT1, accompanied with cilia elongation in renal tubular epithelial cells. Wnt7b, the key ligand for Wnt/β-catenin signaling, was downregulated and nuclear translocation of β-catenin was decreased. The proapoptotic protein was upregulated. In vitro study with HK-2 cells showed that overexpression of IFT88 lengthened the cilia, inhibited β-catenin signaling. Besides, IFT88 overexpression suppressed cell proliferation, activated autophagy, and induced cell apoptosis. Inhibition of autophagy partly restored the cilia length and cell viability. Likewise, knockdown of DYNLT1 led to cilia elongation, suppressed cell proliferation, and promoted apoptosis in HK-2 cell. However, the cilia elongation induced by DYNLT1 knockdown was not autophagy-dependent, but associated with reactive oxygen species (ROS) accumulation.

Discussion

We elucidated that intrauterine protein malnutrition led to deregulation of ciliogenesis factors and cilia elongation in renal tubular epithelial, inhibited β-catenin signaling, and induced cell apoptosis and ultimately, compromised kidney development.

Risk factors for acute kidney injury after Stanford type A aortic dissection repair surgery: a systematic review and meta-analysis

Background: Risk factors for acute kidney injury (AKI) after Stanford type A aortic dissection (TAAD) repair are inconsistent in different studies. This meta-analysis systematically analyzed the risk factors so as to early identify the therapeutic targets for preventing AKI.

Methods: Studies exploring risk factors for AKI after TAAD repair were searched from four databases from inception to June 2022. The synthesized incidence and risk factors of AKI and its impact on mortality were calculated.

Results: Twenty studies comprising 8223 patients were included. The synthesized incidence of postoperative AKI was 50.7%. Risk factors for AKI included cardiopulmonary bypass (CPB) time >180 min [odds ratio (OR), 4.89, 95% confidence interval (CI), 2.06–11.61, I² = 0%], prolonged operative time (>7 h) (OR, 2.73, 95% CI, 1.95–3.82, I² = 0), advanced age (per 10 years) (OR, 1.34, 95% CI, 1.21–1.49, I² = 0], increased packed red blood cells (pRBCs) transfusion perioperatively (OR, 1.09, 95% CI, 1.07–1.11, I² = 42%), elevated body mass index (per 5 kg/m²) (OR, 1.23, 95% CI, 1.18–1.28, I² = 42%) and preoperative kidney injury (OR, 3.61, 95% CI, 2.48–5.28, I² = 45%). All results were meta-analyzed using fixed-effects model finally (p < 0.01). The in-hospital or 30-day mortality was higher in patients with postoperative AKI than in that without AKI [risk ratio (RR), 3.12, 95% CI, 2.54–3.85, p < 0.01].

Conclusions: AKI after TAAD repair increased the in-hospital or 30-day mortality. Reducing CPB time and pRBCs transfusion, especially in elderly or heavier weight patients, or patients with preoperative kidney injury were important to prevent AKI after TAAD repair surgery.

Long-Term Consequences of Increased Activity of Urine Enzymes After Cardiac Surgery - A Prospective Observational Study

Introduction

Cardiac surgery associated AKI (CSA-AKI) complicates recovery and may be associated with a greater risk of developing chronic kidney disease and mortality. The aim of this study was to assess long-term clinical consequences of transient increased activity of urinary enzymes after cardiac surgery (CS).

Methods

An observational study was conducted in a group of 88 adult patients undergoing planned coronary artery bypass grafting (CABG), but all samples were obtained from 79 patients. The activity of urinary enzymes: N-acetyl-beta-glucosaminidase (NAG), arylsulfatase A (ASA) and beta-glucuronidase was evaluated in sequential urine samples. A comparative analysis of biochemical parameters was performed regarding the occurrence of acute kidney injury (AKI) defined by KIDGO at 24 hours, at day 30 and 5-years after the operation.

Results

During the first 24 hours after CS AKI was diagnosed in 13 patients. A comparison of the activity of urinary enzymes in pre-defined time-points showed significant differences for ASA and NAG (post OP-sample p < 0.028 and p < 0.022; POD 1 sample p < 0.004 and p < 0.001 respectively). No patient had any biochemical or clinical features of kidney failure at day 30. In the AKI group kidney failure was diagnosed in 36% of patients within 5 years of follow-up as opposed to 5% in the no AKI group. The activities of tubular enzymes in urine reflect a general injury of kidney tubules during and after the operation. However, they are not ideal biomarkers for prediction of the degree of kidney injury and further poor prognosis of CS-AKI.

Dextran-based priming solution during cardiopulmonary bypass attenuates renal tubular injury-A secondary analysis of randomized controlled trial in adult cardiac surgery patients

BACKGROUND

Acute kidney injury (AKI) is a well-known complication after cardiac surgery and cardiopulmonary bypass (CPB). In the present secondary analysis of a blinded randomized controlled trial, we evaluated the effects of a colloid-based versus a conventional crystalloid-based prime on tubular injury and postoperative renal function in patients undergoing cardiac surgery with CPB.

METHODS

Eighty-four adult patients undergoing cardiac surgery with CPB were randomized to receive either a crystalloid- or colloid- (dextran 40) based CPB priming solution. The crystalloid solution was based on Ringer-Acetate plus mannitol. The tubular injury biomarker, N-acetyl-b-D-glucosaminidase (NAG), serum creatinine and diuresis were measured before, during and after CPB. The incidence of AKI was assessed according to the KDIGO criteria.

RESULTS

The urinary-NAG/urinary-creatinine ratio rose in both groups during and after CPB, with a more pronounced increase in the crystalloid group (p = .038). One hour after CPB, the urinary-NAG/urinary-creatinine ratio was 88% higher in the crystalloid group (4.7 ± 6.3 vs. 2.5 ± 2.7, p = .045). Patients that received the dextran 40-based priming solution had a significantly lower intraoperative diuresis (p < .001) compared to the crystalloid group. The incidence of AKI was 18% in the colloid and 22% in the crystalloid group (p = .66). Postoperative serum creatinine did not differ between groups.

CONCLUSIONS

In patients undergoing cardiac surgery with CPB, colloid-based priming solution (dextran 40) induced less renal tubular injury compared to a crystalloid-based priming solution. Whether a colloid-based priming solution will improve renal outcome in high-risk cardiac surgery, or not, needs to be evaluated in future studies on higher risk cardiac surgery patients.

En Bloc Arch Reconstruction With the Frozen Elephant Trunk Technique for Acute Type a Aortic Dissection

Objective: The study objective was to evaluate the effect of en bloc arch reconstruction with frozen elephant trunk (FET) technique for acute type A aortic dissection.

Methods: 41 patients with acute Stanford type A dissection underwent en bloc arch reconstruction combined with FET implantation between April 2018 and August 2020. The mean age of the patients was 46 ± 13 years, and 9 patients were female. One patient had Marfan syndrome. Six patients had pericardial tamponade, 9 had pleural effusion, 5 had transient cerebral ischemic attack, and 3 had chronic kidney disease.

Results: The hospital mortality rate was 9.8% (4 patients). 2 (4.9%) patients had stroke, 23 (56.1%) had acute kidney injury, and 5 (12.2%) had renal failure requiring hemodialysis. During follow-up, the rate of complete false lumen thrombosis was 91.6% (33/36) around the FET, 69.4% (25/36) at the diaphragmatic level, and 27.8% (10/36) at the superior mesenteric artery level. The true lumen diameter at the same three levels of the descending aorta increased significantly while the false lumen diameter reduced at the two levels: pulmonary bifurcation and the diaphragm. The 1-, 2-and 3-year actuarial survival rates were 90.2% [95% confidence interval (CI), 81.2–99.2], 84.2% (95% CI, 70.1–98.3) and 70.2% (95% CI, 42.2–98), respectively.

Conclusions: In patients with acute type A dissection, en bloc arch reconstruction with FET technique appeared to be feasible and effective with early clinical follow-up results. Future studies including a large sample size and long-term follow-up are required to evaluate the efficacy.

Drinking water heavy metal toxicity and chronic kidney diseases: a systematic review

Heavy metals in drinking water can threat human health and may induce several diseases. The association between heavy metals exposure and chronic kidney disease (CKD) has been indicated by few epidemiological studies. We conducted a systematic review of the epidemiologic publications of the association between exposure to heavy metals through drinking water and CKD. Keywords related to heavy metals and kidney diseases on MeSH were identified and searched in PubMed, Google Scholar, Scopus, Ovid-Medline and Web of Science until July 2020. 14 publications met our inclusion criteria and included in the current review. The included articles were conducted on the association between arsenic, cadmium, lead and chromium in drinking water and CKD. Our study could not find strong evidence between heavy exposure to through drinking water and CKD, except for arsenic. The negative association was found between arsenic and lead and glomerular filtration rate (eGFR). The positive correlation was observed between cadmium exposure and urinary N-acetyl-β-d-glucosaminidase (NAG) concentrations, and also arsenic and chromium exposure and kidney injury molecule (KIM-1). Assessment of studies showed an association between arsenic, cadmium, lead and chromium and albuminuria and proteinuria, without CKD outcomes. Current systematic study showed few evidence for exposure to arsenic, cadmium, lead and chromium through drinking water and incidence of kidney problems. However, more epidemiological studies are required to confirm this association.

Diagnosis of Cardiac Surgery-Associated Acute Kidney Injury

Acute kidney injury after cardiac surgery is characterized by specific patterns of damage and recovery that are important to consider for management and outcome. The Kidney Disease: Improving Global Outcomes (KDIGO) classification covers only part of the conceptual framework and is thus insufficient for a comprehensive diagnosis. This review highlights the strengths and limitations of the recent criteria and provides an overview of biomarkers of cardiac surgery-associated acute kidney injury (CSA-AKI). The evolving understanding of CSA-AKI as a time-sensitive condition has increased the demand to enhance the diagnostic criteria and translate biomarkers into clinical practice.

Total arch replacement in patients with chronic kidney disease

BACKGROUND

We investigated the effect of preoperative renal dysfunction on postoperative outcomes in patients undergoing elective isolated total arch replacement (TAR) with mild hypothermic lower body circulatory arrest with antegrade selective cerebral perfusion (SCP).

METHODS

One hundred and forty-four patients who had undergone elective isolated TAR between January 2002 and December 2019 were retrospectively analyzed. Patients were divided into two groups according to whether their preoperative estimated glomerular filtration rate (eGFR) was lower than or higher than 60 ml/min/1.73 m² . We compared perioperative data and mid-term outcomes after adjusting for patients' baseline characteristics using weighted logistic regression analysis and inverse probability of treatment weighting.

RESULTS

More patients underwent postoperative stroke in the chronic kidney disease group compared with the normal group (2.8% vs. 0%, respectively; p = .049). Overall 30-day mortality and hospital mortality were 0% in both groups, and there was no significant difference in overall survival between the two groups (log-rank test, p = .129). Multivariate Cox proportional hazard analysis showed that eGFR < 60 ml/min/1.73 m² was not an independent predictor (hazard ratio: 1.636, 95% confidence interval 0.829-3.231; p = .156).

CONCLUSIONS

Preoperative eGFR <60 ml/min/1.73 m² was not associated with worse outcomes after elective isolated TAR with mild hypothermic lower body circulatory arrest with antegrade SCP.

Acute kidney injury following coronary revascularization procedures in patients with advanced CKD

BACKGROUND

Previous studies reported that compared with percutaneous coronary interventions (PCIs), coronary artery bypass grafting (CABG) is associated with a reduced risk of mortality and repeat revascularization in patients with mild to moderate chronic kidney disease (CKD) and end-stage renal disease (ESRD). Information about outcomes associated with CABG versus PCI in patients with advanced stages of CKD is limited. We evaluated the incidence and relative risk of acute kidney injury (AKI) associated with CABG versus PCI in patients with advanced CKD.

METHODS

We examined 730 US veterans with incident ESRD who underwent a first CABG or PCI up to 5 years prior to dialysis initiation. The association of CABG versus PCI with AKI was examined in multivariable adjusted logistic regression analyses.

RESULTS

A total of 466 patients underwent CABG and 264 patients underwent PCI. The mean age was 64 ± 8 years, 99% were male, 20% were African American and 84% were diabetic. The incidence of AKI in the CABG versus PCI group was 67% versus 31%, respectively (P < 0.001). The incidence of all stages of AKI were higher after CABG compared with PCI. CABG was associated with a 4.5-fold higher crude risk of AKI {odds ratio [OR] 4.53 [95% confidence interval (CI) 3.28-6.27]; P < 0.001}, which remained significant after multivariable adjustments [OR 3.50 (95% CI 2.03-6.02); P < 0.001].

CONCLUSION

CABG was associated with a 4.5-fold higher risk of AKI compared with PCI in patients with advanced CKD. Despite other benefits of CABG over PCI, the extremely high risk of AKI associated with CABG should be considered in this vulnerable population when deciding on the optimal revascularization strategy.

Application of a Modified Extracorporeal Circulation Perfusion Method During Surgery for Acute Stanford Type A Aortic Dissection

AIM

The aim of this study was to investigate the effect of the modified extracorporeal circulation perfusion method during surgery for acute Stanford type A aortic dissection in patients who underwent stented elephant trunk implantation and arch replacement.

METHOD

A total of 69 patients with acute Stanford type A aortic dissection who underwent stented elephant trunk implantation and arch replacement were retrospectively analysed from 2017 to 2018. According to the perfusion method of extracorporeal circulation, patients were divided into a routine perfusion (RP) group and a modified perfusion (MP) group. Clinical data were collected, including the time of extracorporeal circulation and deep hypothermic circulatory arrest, incidence of acute kidney injury and neurological complications, and comparisons between the two groups were conducted by using independent sample t-tests for normally distributed qualitative data, the Mann-Whitney U-test for skewed qualitative data, and the chi square test or Fisher's exact test for categorical data.

RESULTS

There were 55 (80%) males and 14 (20%) females in the entire cohort, and the mean ± standard deviation age was 50.4±9.0 years. A total of 53 (77%) patients were included in the RP group, and 16 (23%) were included in the MP group. Patients in the MP group were older (55.5±7.8 vs 48.8±8.9 years), and the difference was significant (p=0.008). Compared with the RP group, the time of extracorporeal circulation (218.0 [44.7] vs 246.0 [58.0] min; p=0.005) and deep hypothermic circulatory arrest (4.0 [2.0] vs 25.0 [10.0] min; p<0.001) was shorter, and the incidence of postoperative acute kidney injury (n=6 [37.5%] vs n=36 [67.9%]; p=0.029) was lower in the MP group; the differences were significant. Six (6) patients died in the RP group; no patients died in the MP group. The total in-hospital mortality rate was 8.7%.

CONCLUSIONS

The modified extracorporeal circulation perfusion method is feasible, with satisfactory results.

Effects of milrinone on renal perfusion, filtration and oxygenation in patients with acute heart failure and low cardiac output early after cardiac surgery

PURPOSE

Early postoperative heart failure is common after cardiac surgery, and inotrope treatment may impact renal perfusion and oxygenation. We aimed to study the renal effects of the inodilator milrinone when used for the treatment of heart failure after weaning from cardiopulmonary bypass (CPB).

MATERIAL AND METHODS

In 26 patients undergoing cardiac surgery with CPB, we used renal vein catheterization to prospectively measure renal blood flow (RBF), glomerular filtration rate (GFR), and renal oxygenation. Patients who developed acute heart failure and low cardiac output (cardiac index <2.1 L/min/m²) at 30 min after weaning from CPB (n = 7) were given milrinone, and the remaining patients (n = 19) served as controls. Additional measurements were made at 60 min after CPB.

RESULTS

In patients with acute postoperative heart failure, before receiving milrinone, renal blood flow was lower (-33%, p < .05) while renal oxygen extraction was higher (41%, p < .05) compared to the control group. Milrinone increased cardiac index (21%, p < .001), RBF (36%, p < .01) and renal oxygen delivery (35%, p < .01), with no significant change in GFR and oxygen consumption compared to the control group.

CONCLUSIONS

In patients with acute heart failure after weaning from CPB, the milrinone-induced increase in cardiac output was accompanied by improved renal oxygenation.

TRIAL REGISTRATION

ClinicalTrials.gov; identifier NCT02405195, date of registration; March 27, 2015, and NCT02549066, date of registration; 9 September 2015.

N-acety-b-D-glucosaminidase: A potential biomarker for early detection of acute kidney injury in acute chest pain

AIM

Acute kidney injury (AKI) is often underdiagnosed due to several limitations of the renal marker creatinine. Tubular urinary biomarkers may substantially contribute to diagnose AKI early. For early detection of AKI, we evaluated for the first time N-acetyl-β-d-glucosaminidase (NAG), Kidney-injury-molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) in acute chest pain.

METHODS

We included 402 chest pain patients aged 18 to 95 years seen in the emergency department. From 311 subjects, blood and urine samples were collected.

RESULTS

Thirty-three patients developed an AKI and showed a significant increase in all three tubular markers compared to patients without AKI (each P < .001). According to receiver operating characteristic (ROC) analysis, combining NAG and creatinine showed a significantly increased area under the curve (AUC) compared to creatinine alone (AUC: 0.75 vs 0.87; P < .001). KIM-1, NGAL and cystatin C showed no significant differences in AUC compared to creatinine. In 120 individuals with blood and urine sampling before contrast media exposure, ROC analysis showed a significantly improved diagnostic performance for the combination of both (AUC: 0.83 vs creatinine AUC: 0.66; P = .004). AKI occurrence showed no dependency from CM volume. NAG presented as an independent AKI predictor beside creatinine, age, the diagnosis of myocardial infarction and mean arterial pressure. Regarding the prognostic value for renal replacement therapy, the combination of NAG and creatinine showed a significantly lager AUC than creatinine (AUC: 0.95 vs AUC: 0.85; P < .001).

CONCLUSION

NAG presented as a promising marker of impending AKI and the necessity of renal replacement therapy.

Cardiopulmonary bypass time is an independent risk factor for acute kidney injury in emergent thoracic aortic surgery: a retrospective cohort study

BACKGROUND

Thoracic aortic surgery and cardiopulmonary bypass are both associated with development of postoperative acute kidney injury. In this study, we undertook to investigate the relationship between cardiopulmonary bypass time and postoperative acute kidney injury in patients undergoing thoracic aortic surgery for acute DeBakey Type I aortic dissection.

METHODS

All patients receiving thoracic aortic surgery for acute DeBakey Type I aortic dissection in Beijing Anzhen hospital from December 2015 to April 2017 were included. Cardiopulmonary bypass time was recorded during surgery. Acute kidney injury was defined based on the Kidney Disease Improving Global Outcomes criteria. A total of 115 consecutive patients were eventually analyzed.

RESULTS

The overall incidence of acute kidney injury was 53.0% (n = 61). The average age was 47.8 ± 10.7 years; 74.8% were male. Mean cardiopulmonary bypass time was 211 ± 56 min. In-hospital mortality was 7.8%. Multivariate logistic regression revealed that cardiopulmonary bypass time was independently associated with the occurrence of postoperative acute kidney injury after adjust confounding factors (odds ratio = 1.171; 95% confidence interval: 1.002-1.368; P = 0.047).

CONCLUSIONS

Cardiopulmonary bypass time is independently associated with an increased hazard of acute kidney injury after thoracic aortic surgery for acute DeBakey Type I aortic dissection. Further understanding of the mechanism of this association is crucial to the design of preventative strategies.

Urinary biomarkers predict advanced acute kidney injury after cardiovascular surgery

BACKGROUND

Acute kidney injury (AKI) after cardiovascular surgery is a serious complication. Little is known about the ability of novel biomarkers in combination with clinical risk scores for prediction of advanced AKI.

METHODS

In this prospectively conducted multicenter study, urine samples were collected from 149 adults at 0, 3, 6, 12 and 24 h after cardiovascular surgery. We measured urinary hemojuvelin (uHJV), kidney injury molecule-1 (uKIM-1), neutrophil gelatinase-associated lipocalin (uNGAL), α-glutathione S-transferase (uα-GST) and π-glutathione S-transferase (uπ-GST). The primary outcome was advanced AKI, under the definition of Kidney Disease: Improving Global Outcomes (KDIGO) stage 2, 3 and composite outcomes were KDIGO stage 2, 3 or 90-day mortality after hospital discharge.

RESULTS

Patients with advanced AKI had significantly higher levels of uHJV and uKIM-1 at 3, 6 and 12 h after surgery. When normalized by urinary creatinine level, uKIM-1 in combination with uHJV at 3 h post-surgery had a high predictive ability for advanced AKI and composite outcome (AUC = 0.898 and 0.905, respectively). The combination of this biomarker panel (normalized uKIM-1, uHJV at 3 h post-operation) and Liano's score was superior in predicting advanced AKI (AUC = 0.931, category-free net reclassification improvement of 1.149, and p <  0.001).

CONCLUSIONS

When added to Liano's score, normalized uHJV and uKIM-1 levels at 3 h after cardiovascular surgery enhanced the identification of patients at higher risk of progression to advanced AKI and composite outcomes.

Preoperative blood morphology and incidence of acute kidney injury after on-pump coronary artery bypass grafting - a single-center preliminary report

Introduction

Acute kidney injury (AKI) after coronary artery bypass grafting (CABG) performed in cardiopulmonary bypass (CPB) may complicate the postoperative course and has a negative impact on outcome. In some cases, postoperative AKI develops in spite of normal baseline creatinine concentration and estimated glomerular filtration rate (eGFR).

Aim

To examine whether there is any association between the preoperative blood morphology and incidence of post-operative AKI.

Material and methods

The study involved 62 consecutive patients with the mean age of 64.0 ±7.4 years who underwent CABG in CPB. Before surgery, blood morphology and biochemistry were analyzed. Patients with eGFR below 60 ml/min/1.73 m² were excluded. After the operation, parameters of renal function were checked systematically. Acute kidney injury was defined according to the Acute Kidney Injury Network (AKIN) classification.

Results

Twenty-one (33.9%) patients presented AKI (group AKI), although in the majority of them (n = 16) it was temporary and medical management was enough to cure AKI. Only in 1 (1.6%) case was renal replacement therapy necessary. In group AKI, patients’ preoperative hemoglobin concentration (8.46 ±0.72 mM/l), red blood cell count (4.51 ±0.39 × 10¹²/l) and hematocrit (0.40 ±0.04) were significantly lower (p < 0.05) than in group C (9.07 ±0.57 mM/l; 4.78 ±0.36 × 10¹²/l; 0.43 ±0.03, respectively). Interestingly, the baseline parameters of renal function were comparable between groups.

Conclusions

Hemoglobin concentration and red blood cell counts close to the lower limit of the normal range may enable identification of patients at risk of AKI early after CABG in CPB among individuals with normal preoperative biochemical parameters of renal function.