RIFLE criteria for acute kidney injury in aortic arch surgery

Bradykinin induces acute kidney injury after hypothermic circulatory arrest through the repression of the Nrf2-xCT pathway

Postoperative acute kidney injury (AKI) is a common complication in patients undergoing deep hypothermic circulatory arrest (HCA); however, its underlying pathogenesis is unclear. In this study, we established a rat cardiopulmonary bypass model and demonstrated that hypothermia during HCA, rather than circulatory arrest, was responsible for the occurrence of AKI. By recruiting 56 patients who underwent surgery with HCA and analyzing the blood samples, we found that post-HCA AKI was associated with an increase in bradykinin. Animal experiments confirmed this and showed that hypothermia during HCA increased bradykinin levels by increasing kallikrein expression. Mechanistically, bradykinin inhibited the Nrf2-xCT pathway through B2R and caused renal oxidative stress damage. Application of Icatibant, a B2R inhibitor, reversed changes in the Nrf2-xCT pathway and oxidative stress damage. Finally, Icatibant reversed hypothermia-induced AKI in vivo. This finding reveals the pathogenesis of AKI after HCA and helps to provide therapeutic strategy for patients with post-HCA AKI.

Long-term outcomes of total arch replacement with bilateral antegrade cerebral perfusion using the "arch first" approach

OBJECTIVE

To report outcomes of total arch replacement (TAR) with hypothermic circulatory arrest and bilateral antegrade cerebral perfusion (bACP) using an "arch first" approach for acute Type A aortic dissection (ATAAD). The "arch first" approach involved revascularization of the aortic arch branch vessels with uninterrupted ACP, before lower body circulatory arrest, while the patient was cooling.

METHODS

This was an observational study of aortic surgeries from 2010 to 2021. All patients who underwent TAR with bACP for ATAAD were included. Short-term and long-term outcomes were reported utilizing descriptive statistics and Kaplan-Meier survival estimation.

RESULTS

A total of 215 patients were identified who underwent TAR + bACP for ATAAD. Age was 59.0 [49.0-67.0] years and 35.3% were female. 73 patients (34.0%) underwent a concomitant aortic root replacement, 188 (87.4%) had aortic cannulation, circulatory arrest time was 37.0 [26.0-52.0] minutes, and nadir temperature was 20.8 [19.4-22.5] degrees Celsius. 35 patients (16.3%) had operative mortality (STS definition), 17 (7.9%) had a new stroke, 79 (36.7%) had prolonged mechanical ventilation (>24 h), 35 (16.3%) had acute renal failure (by RIFLE criteria), and 128 (59.5%) had blood product transfusions. One-year survival was 77.1%, while 5-years survival was 67.1%. During follow-up, there were 23 (10.7%) reinterventions involving the descending thoracic aorta - either thoracic endovascular aortic repair or open thoracoabdominal aortic replacement.

CONCLUSIONS

Among patients with ATAAD, short-term postoperative outcomes after TAR + bACP using the "arch first" approach are acceptable. Moreover, this operative strategy may furnish long-term durability, with a reasonably low reintervention rate and satisfactory overall survival.

Central venous pressure combined with renal venous impedance index in predicting the acute kidney injury after thoracic and abdominal (non-cardiac) surgery

BACKGROUND

In the 21st century, 13% of patients undergoing open abdominal surgery, 25% of patients undergoing heart surgery, and 57% of patients admitted to the intensive care unit (ICU) are affected by acute kidney injury (AKI).

METHODS

This prospective observational study included patients admitted directly to the ICU between June 2021 and December 2021.

RESULTS

A total of 81 patients were enrolled after thoracic and abdominal (non-cardiac) surgery; 36 patients (44.4%) were diagnosed with AKI occurred within 7 days after surgery. Six-hour postoperative central venous pressure(CVP) was a risk factor for AKI in thoracic and abdominal (non-cardiac) postoperative patients (odds ratio [OR], 1.418; 95% confidence intervals [CI], 1.106-1.819; P = 0.006). Six-hour postoperative vein impedance index(VII) and CVP were significantly positively correlated (P = 0.031). The combination of 6-h postoperative VII with CVP (VII ≥0.34, CVP ≥7.5 mmHg) showed an area under the curve (AUC) of 0.787, In the subgroup analysis of patients with 6-h postoperative CVP <7.5 mmHg, there was a significant statistical difference in 6-h postoperative VII between the groups and those without AKI (P = 0.048). At 6-h postoperative CVP <7.5 mmHg, VII of ≥0.44 had a predictive value for AKI after thoracic and abdominal (non-cardiac) surgery, with an AUC of 0.669, a sensitivity of 41.2%, and a specificity of 94.4%.

CONCLUSION

Six-hour postoperative CVP combined with VII can better predict the occurrence of AKI occurred within 7 days after thoracic and abdominal (non-cardiac) surgery but cannot predict the severity of AKI.

Quantifying the effects of circulatory arrest on acute kidney injury in aortic surgery

OBJECTIVES

We aim to investigate the association between parameters surrounding circulatory arrest and postoperative acute kidney injury in aortic surgery.

METHODS

This is a single-center retrospective study of 1118 adult patients who underwent aortic repair with median sternotomy between January 2010 and May 2019. Acute kidney injury was defined on the basis of a modified version of the 2012 Kidney Disease Improving Global Outcomes Scale that excluded urine output. The primary outcome of interest was any stage of acute kidney injury.

RESULTS

Circulatory arrest was required in 369 patients, and 307 patients (27.5%) developed acute kidney injury: stage 1 in 241 patients, stage 2 in 38 patients, and stage 3 in 28 patients. Lower-body ischemia (the period during circulatory arrest without blood flow to kidneys) duration was not associated with acute kidney injury after multivariable logistic regression (1-40 minutes, odds ratio, 0.67; 95% confidence interval, 0.43-1.04; P = .075; >40 minutes, odds ratio, 0.67; 95% confidence interval, 0.29-1.55; P = .356). Hypertension (odds ratio, 1.65; 95% confidence interval, 1.09-2.54; P = .020), preoperative estimated glomerular filtration rate (odds ratio, 0.99; 95% confidence interval, 0.98-1.00; P = .010), packed red blood cell transfusion volume (odds ratio, 1.00; 95% confidence interval, 1.00-1.00; P = .028), and nadir temperature (odds ratio, 0.93; 95% confidence interval, 0.88-0.99; P = .013) were independently associated with acute kidney injury after multivariable analysis. Although there was a positive association between lower-body ischemia duration and development of acute kidney injury with univariable cubic spline, the positive curve was flattened after adjustment for the described variables.

CONCLUSIONS

Within the range of our clinical practice, prolonged lower-body ischemia duration was not independently associated with postoperative acute kidney injury, whereas nadir temperature was.

Acute Kidney Injury in Patients Undergoing Surgery for Type A Acute Aortic Dissection

BACKGROUND

Acute kidney injury (AKI) after repair of type A acute aortic dissection (TAAAD) has been shown to affect both short- and long-term outcomes. This study aimed to validate the impact of postoperative AKI on in-hospital and long-term outcomes in a large population of dissection patients presenting to multinational aortic centers. Additionally, we assessed risk factors for AKI including surgical details.

METHODS

Patients undergoing surgical repair for TAAAD enrolled in the International Registry of Acute Aortic Dissection database were evaluated to determine the incidence and risk factors for the development of AKI.

RESULTS

A total of 3307 patients were identified. There were 761 (23%) patients with postoperative AKI (AKI group) vs 2546 patients without (77%, non-AKI group). The AKI group had a higher rate of in-hospital mortality (n = 193, 25.4% vs n = 122, 4.8% in the non-AKI group, P < .001). Additional postoperative complications were also more common in the AKI group including postoperative cerebrovascular accident, reexploration for bleeding, and prolonged ventilation. Independent baseline characteristics associated with AKI included a history of hypertension, diabetes, chronic kidney disease, evidence of malperfusion on presentation, distal extent of dissection to abdominal aorta, and longer cardiopulmonary bypass time. Kaplan-Meier survival curves revealed decreased 5-year survival among the AKI group (P < .001).

CONCLUSIONS

AKI occurs commonly after TAAAD repair and is associated with a significantly increased risk of operative and long-term mortality. In this large study using the International Registry of Acute Aortic Dissection database, several factors were elucidated that may affect risk of AKI.

Novel Estimates of Renal Function are Associated with Short-Term Left Ventricular Assist Device Outcomes

INTRODUCTION

Although preoperative kidney function has been associated with left ventricular assist device (LVAD) outcomes, most previous estimates of glomerular filtration rates (eGFRs) have utilized race in the calculation. Recently, novel eGFR equations independent of race have been suggested and validated. Therefore, we undertook this study to evaluate the predictive value of a novel, non-race-based eGFR calculation on short-term LVAD outcomes.

METHODS

We conducted a retrospective review of all primary LVAD implants from 2017 to 2022 at our institution. eGFR was calculated using the novel Chronic Kidney Disease Epidemiology Collaboration 2021 formula (CKD-EPI 2021). eGFR was also calculated according to the Modification of Diet in Renal Disease equation for historical reference. Primary stratification was by eGFR: ≥60, 30-60, and <30. The primary outcome was 1-y survival. Multivariable Cox proportional hazards regression modeling was used to further evaluate the impact of kidney function on 1-y mortality.

RESULTS

From 2017 to 2022, 91 patients underwent LVAD implantation with a HeartMate 3 device. The average age was 65.20 ± 11.08, 77 (84.62%) were male, and 14 (15.38%) were Black. The mean CKD-EPI 2021 eGFR was 56.07 ± 23.55 compared with 54.72 ± 26.37 as calculated by Modification of Diet in Renal Disease (P = 0.719). Overall, 30-d and 1-y survival was 96.7% and 85.0%, respectively. When stratified by eGFR, there was a significant difference in 1-y survival (≥60, 93.46%; 30-60, 87.36%; <30, 62.75%; P = 0.016). On multivariable analysis, a preoperative eGFR <30 was associated with an increased hazard of 1-y mortality (5.58 [1.06-29.17], P = 0.043).

CONCLUSIONS

In conclusion, non-race-based estimates of renal function are predictive of short-term LVAD outcomes. Further investigation of this phenomenon is warranted.

Preoperative Short-Term Restriction of Sulfur-Containing Amino Acid Intake for Prevention of Acute Kidney Injury After Cardiac Surgery: A Randomized, Controlled, Double-Blind, Translational Trial

Background Acute kidney injury (AKI) is a major risk factor for chronic kidney disease and increased mortality. Until now, no compelling preventive or therapeutic strategies have been identified. Dietary interventions have been proven highly effective in organ protection from ischemia reperfusion injury in mice and restricting dietary intake of sulfur-containing amino acids (SAA) seems to be instrumental in this regard. The UNICORN trial aimed to evaluate the protective impact of restricting SAA intake before cardiac surgery on incidence of AKI. Methods and Results In this single-center, randomized, controlled, double-blind trial, 115 patients were assigned to a SAA-reduced formula diet (LowS group) or a regular formula diet (control group) in a 1:1 ratio for 7 days before scheduled cardiac surgery. The primary end point was incidence of AKI within 72 hours after surgery, secondary end points included increase of serum creatinine at 24, 48, and 72 hours as well as safety parameters. Quantitative variables were analyzed with nonparametric methods, while categorical variables were evaluated by means of Chi-square or Fisher test. SAA intake in the group with SAA reduced formula diet was successfully reduced by 77% (group with SAA reduced formula diet, 7.37[6.40-7.80] mg/kg per day versus control group, 32.33 [28.92-33.60] mg/kg per day, P<0.001) leading to significantly lower serum levels of methionine. No beneficial effects of SAA restriction on the rate of AKI after surgery could be observed (group with SAA reduced formula diet, 23% versus control group, 16%; P=0.38). Likewise, no differences were recorded with respect to secondary end points (AKI during hospitalization, creatinine at 24, 48, 72 hours after surgery) as well as in subgroup analysis focusing on age, sex, body mass index and diabetes. Conclusions SAA restriction was feasible in the clinical setting but was not associated with protective properties in AKI upon cardiac surgery. Registration URL: https://www.clinicaltrials.gov; Unique Identifier: NCT03715868.

Post-Operative Kidney Function Using Deep Hypothermic Circulatory Arrest (DHCA) in Aortic Arch Operation

Background

Although deep hypothermic circulatory arrest (DHCA) is a useful option to protect the central nervous system during aortic arch operations, the influence of simultaneous renal ischemia remains controversial.

Patients and Methods

This is a retrospective observational study. Sixty-three patients who underwent thoracic aortic surgery with DHCA and 24 patients who underwent cardiac surgery without DHCA were included in this study. The mean age, preoperative serum creatinine (Cr) level, preoperative estimated glomerular filtration rate (eGFR), peak serum Cr level up to 48 hrs post-operative, elevation rate of Cr compared to the preoperative serum Cr, urine volume rate up to 48 hrs post-operative and AKI staging using the KDIGO criteria were estimated for each patient. Clinical parameters for 3 months after the operation and the 3-month post-operative mortality rate were assessed. Mean values indicating kidney function or distribution of the AKI stages were compared between patients with and without DHCA. Patients with DHCA were further divided according to the duration of ischemia to compare the values for the kidney function of each group, distribution of AKI stages and mortality.

Results

The parameters indicating AKI of the patients with DHCA were significantly more severe than those without DHCA. Patients who had undergone an ischemic state for more than 40 min revealed significantly higher peak serum Cr, elevation rate of serum Cr, less urine volume up to 48 hrs post-operative compared with those without DHCA. Distribution of the AKI stages was related to the duration of ischemia. The 3-month post-operative mortality of the patients with DHCA was significantly higher than those without DHCA.

Limitations

This study had limitations such as its retrospective design and small number patients, and the data will be required confirmation with other prospective studies.

Conclusion

DHCA is closely related to AKI up to 48 hrs post-operative and death during the 3 months following surgery.

Neutrophil Gelatinase-Associated Lipocalin (NGAL) and cystatin C are early biomarkers of acute kidney injury associated with cardiac surgery

Acute kidney injury (AKI) is a serious complication in as much as half of the patients undergoing cardiac surgery, and early diagnosis and treatment are of the utmost importance. There is a need for robust biomarkers that can detect cardiac surgery-associated AKI (CSA-AKI) prior to rise in plasma creatinine, which typically occurs at least 48 h postoperatively. We compared pre- and 4, 12 and 48 h postoperative plasma (P) neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, urea and creatinine, and urine (U) NGAL, as markers of AKI, in 49 patients (67% men, median age 65 years) scheduled for elective cardiac surgery (e.g. coronary artery bypass graft and/or valve replacement surgery) with the use of extracorporeal circulation. Patients with preoperative sepsis, renal replacement therapy, or estimated glomerular filtration rate <30 mL/min/1.73m² were excluded. P- and U-NGAL were measured using the Roche Modular P (Roche Diagnostics^®) NGAL immunoassay. According to AKIN/KDIGO criteria, nine patients (18%) were diagnosed with CSA-AKI. Compared to patients without CSA-AKI, these patients had significantly higher P-NGAL and P-cystatin C values 4 h (p-values .002 and <.001) and 12 h (p-values <.001 and <.001) postoperatively. The same differences were not observed for U-NGAL. Patients with AKI also had significantly higher P-creatinine 4 and 12 h postoperatively (p-values .001 and <.001), however the rise in P-creatinine was just above the upper reference limit. In conclusion, plasma NGAL and cystatin C seem to detect CSA-AKI earlier than the more commonly used biomarkers creatinine and urea.

Postoperative Fluid Therapy in Adult Cardiac Surgical Patients and Acute Kidney Injury: A Prospective Observational Study

Background Normal saline (0.9% NS) is a common intravenous fluid used worldwide. Recent studies have shown that NS use is associated with increased incidence of acute kidney injury (AKI) and a need for renal replacement therapy (RRT). The practice is changing toward using balanced solutions to prevent AKI. Postcardiac surgery patients are more prone to develop AKI after cardiopulmonary bypass (CPB). We aim to study the type of fluid administrated, incidence of AKI, need for RRT, and overall outcome of these patients.

Methods This prospective observational study was conducted in the cardiothoracic intensive care unit (cardiothoracic and vascular surgery intensive care unit) in a cohort of 197 adult patients who underwent on pump cardiac surgery in our hospital from July 2021 to October 2021 as a pilot study. Data was analyzed using SPSS 20.0 (IBM, Chicago, Illinois, United States). A p-value < 0.05 was considered significant.

Results In our study, 58 (29.34%) patients developed AKI in the first three postoperative days and 16 (8.12%) patients required RRT. Incidence of AKI was found to be higher in patients who received NS only, as fluid of choice was 34.48% compared with other intravenous fluids. Patients with AKI had higher positive fluid balance (p < 0.001), longer CPB (p < 0.001), and aortic cross clamp (p = 0.006) times. Intensive care unit and hospital stay and mortality rates were higher in AKI patients than those without AKI (p < 0.001).

Conclusion Our study demonstrated that NS was the commonly used crystalloid in our patients and was associated with increased incidence of AKI and RRT when compared with other balanced salts solutions.

Does deeper hypothermia reduce the risk of acute kidney injury after circulatory arrest for aortic arch surgery?

OBJECTIVES

The impact of hypothermic circulatory arrest (HCA) temperature on postoperative acute kidney injury (AKI) has not been evaluated. This study examined the association between circulatory arrest temperatures and AKI in patients undergoing proximal aortic surgery with HCA.

METHODS

A total of 759 consecutive patients who underwent proximal aortic surgery (ascending ± valve ± root) including arch replacement requiring HCA between July 2005 and December 2016 were identified from a prospectively maintained institutional aortic surgery database. The primary outcome was AKI as defined by Risk, Injury, Failure, Loss, End Stage Renal Disease (ESRD) criteria. The association between minimum nasopharyngeal (NP) and bladder temperatures during HCA and postoperative AKI was assessed, adjusting for patient-level factors using multivariable logistic regression.

RESULTS

A total of 85% (n = 645) of patients underwent deep hypothermia (14.1-20.0°C), 11% (n = 83) low-moderate hypothermia (20.1-24.0°C) and 4% (n = 31) high-moderate hypothermia (24.1-28.0°C) as classified by NP temperature. When analysed by bladder temperature, 59% (n = 447) underwent deep hypothermia, 22% (n = 170) low-moderate, 16% (n = 118) high-moderate and 3% mild (n = 24) (28.1-34.0°C) hypothermia. The median systemic circulatory arrest time was 17 min. The incidence of AKI did not differ between hypothermia groups, whether analysed using minimum NP or bladder temperature. In the multivariable analysis, the association between degree of hypothermia and AKI remained non-significant whether analysed as a categorical variable (hypothermia group) or as a continuous variable (minimum NP or bladder temperature) (all P > 0.05).

CONCLUSIONS

In patients undergoing proximal aortic surgery including arch replacement requiring HCA, degree of systemic hypothermia was not associated with the risk of AKI. These data suggest that moderate hypothermia does not confer increased risk of AKI for patients requiring circulatory arrest, although additional prospective data are needed.

Thrombotic microangiopathy following aortic surgery with hypothermic circulatory arrest: a single-centre experience of an underestimated cause of acute renal failure

OBJECTIVES

Acute kidney injury (AKI) following surgery involving the heart-lung-machine is associated with high mortality and morbidity. In addition to the known mechanisms, thrombotic microangiopathy (TMA) triggered by the dysregulation of complement activation was recently described as another pathophysiological pathway for AKI following aortic surgery. The aim of this retrospective study was to analyse incidence, predictors and outcome in these patients.

METHODS

Between January 2018 and September 2019, consecutive patients undergoing aortic surgery requiring hypothermic circulatory arrest were retrospectively reviewed. If suspected, diagnostic algorithm was initiated to identify a TMA and its risk factors, and postoperative outcome parameters were comparably investigated.

RESULTS

The incidence of TMA in the analysed cohort (n = 247) was 4.5%. Multivariable logistic regression indicated female gender {odds ratio (OR) 4.905 [95% confidence interval (CI) 1.234-19.495], P = 0.024} and aortic valve replacement [OR 8.886 (95% CI 1.030-76.660), P = 0.047] as independent predictors of TMA, while cardiopulmonary bypass, X-clamp and hypothermic circulatory arrest times showed no statistically significance. TMA resulted in postoperative AKI (82%), neurological disorders (73%) and thrombocytopaenia [31 (interquartile range 25-42) G/l], corresponding to the diagnostic criteria. Operative mortality and morbidity were equal to patients without postoperative TMA, despite a higher incidence of re-exploration for bleeding (27 vs 6%; P = 0.027). After 6 months, survival, laboratory parameters and need for dialysis were comparable between the groups.

CONCLUSIONS

TMA is a potential differential diagnosis for the cause of AKI following aortic surgery regardless of the hypothermic circulatory arrest time. Timely diagnosis and appropriate treatment resulted in a comparable outcome concerning mortality and renal function.

Blood Transfusion and Acute Kidney Injury After Total Aortic Arch Replacement for Acute Stanford Type A Aortic Dissection

AIM

To evaluate the effect of packed red blood cells (pRBCs), fresh frozen plasma (FFP), and platelet concentrate (PC) transfusions on acute kidney injury (AKI) in patients with acute Stanford type A aortic dissection (ATAAD) with total arch replacement (TAR).

METHOD

From December 2015 to October 2017, 421 consecutive patients with ATAAD undergoing TAR were included in the study. The clinical data of the patients and the amount of pRBCs, FFP, and PC were collected. Acute kidney injury was defined using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Logistic regression was used to identify whether pRBCs, FFP, and platelet transfusions were risk factors for KDIGO AKI, stage 3 AKI, and AKI requiring renal replacement therapy (RRT).

RESULTS

The mean ± standard deviation age of the patients was 47.67±10.82 years; 77.7% were men; and the median time from aortic dissection onset to operation was 1 day (range, 0-2 days). The median transfusion amount was 8 units (range, 4-14 units) for pRBCs, 400 mL (range, 0-800 mL) for FFP, and no units (range, 0-2 units) for PC. Forty-one (41; 9.7%) patients did not receive any blood products. The rates of pRBC, PC, and FFP transfusions were 86.9%, 49.2%, and 72.9%, respectively. The incidence of AKI was 54.2%. Considering AKI as the endpoint, multivariate logistic regression showed that pRBCs (odds ratio [OR], 1.11; p<0.001) and PC transfusions (OR, 1.28; p=0.007) were independent risk factors. Considering KDIGO stage 3 AKI as the endpoint, multivariate logistic regression showed that pRBC transfusion (OR, 1.15; p<0.001), PC transfusion (OR, 1.28; p<0.001), a duration of cardiopulmonary bypass (CPB) ≥293 minutes (OR, 2.95; p=0.04), and a creatinine clearance rate of ≤85 mL/minute (OR, 2.12; p=0.01) were independent risk factors. Considering RRT as the endpoint, multivariate logistic regression showed that pRBC transfusion (OR, 1.12; p<0.001), PC transfusion (OR, 1.33; p=0.001), a duration of CPB ≥293 minutes (OR, 3.79; p=0.02), and a creatinine clearance rate of ≤85 mL/minute (OR, 3.34; p<0.001) were independent risk factors.

CONCLUSIONS

Kidney Disease: Improving Global Outcomes-defined stage AKI was common after TAR for ATAAD. Transfusions of pRBCs and PC increased the incidence of AKI, stage 3 AKI, and RRT. Fresh frozen plasma transfusion was not a risk factor for AKI.

Retrograde inferior vena caval perfusion for total aortic arch replacement surgery: a randomized pilot study

Objectives

Antegrade cerebral perfusion (ACP) under moderate hypothermic circulatory arrest is used during total aortic arch replacement surgery (TARS) in patients with acute type A aortic dissection, but it is associated with high mortality and morbidity. We hypothesized that combining ACP with retrograde inferior vena caval perfusion (RIVP) improves outcomes.

Methods

This pilot study was prospective, randomized, controlled and assessor-blinded. Patients scheduled for TARS were randomly treated with either ACP or RIVP + ACP. The primary outcome was a composite of mortality and major complications including paraplegia, postoperative renal failure, severe liver dysfunction, and gastrointestinal complications. Secondary outcomes included neurological complications, length of intubation and requirement of blood products.

Results

A total of 76 patients were recruited (n = 38 per group). Primary outcome occurred in 23 patients (61%) in the ACP group and 16 (42%) in the RIVP + ACP group (OR: 0.60, 95% CI: 0.21–1.62; p = 0.31). There was a lower incidence of transient neurological deficits in the RIVP + ACP group (26% vs. 58%, OR: 0.26; 95% CI: 0.10–0.67,p = 0.006;). The RIVP + ACP group underwent shorter intubation (25 vs 47 h, p = 0.022) and required fewer blood products (red cells, 3.8 units vs 6.5 units, p = 0.047; platelet: 2.0 units vs 2.0 units, p = 0.023) compared with the ACP group.

Conclusions

RIVP + ACP may be associated with lower incidence of transient neurological deficits, shorter intubation and less blood transfusion requirement than ACP alone during TARS. Multi-center, randomized trials with larger samples are required to determine whether RIVP + ACP is associated with lower rates of mortality and major complications.

Trial registration: Pilot study of a RCT registered in clinicaltrials.gov (NCT03607786), Registered 30 July, 2018—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03607786.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02002-9.

Development of a practical prediction score for acute renal injury after surgery for Stanford type A aortic dissection

OBJECTIVES

Acute kidney injury (AKI) is a common complication of cardiovascular surgery that is associated with increased mortality, especially after surgeries involving the aorta. Early detection and prevention of AKI in patients with aortic dissection may help improve outcomes. The objective of this study was to develop a practical prediction score for AKI after surgery for Stanford type A acute aortic dissection (TAAAD).

METHODS

This was a retrospective cohort study that included 2 independent hospitals. A larger cohort of 326 patients from The Second Hospital of Jilin University was used to identify the risk factors for AKI and to develop a risk score. The derived risk score was externally validated in a separate cohort of 102 patients from the other hospital.

RESULTS

The scoring system included the following variables: (i) age >45 years; (ii) body mass index >25 kg/m2; (iii) white blood cell count >13.5 × 109/l; and (iv) lowest perioperative haemoglobin <100 g/l, cardiopulmonary bypass duration >150 min and renal malperfusion. On receiver operating characteristic curve analysis, the score predicted AKI with fair accuracy in both the derivation [area under the curve 0.778, 95% confidence interval (CI) 0.726-0.83] and the validation (area under the curve 0.747, 95% CI 0.657-0.838) cohorts.

CONCLUSIONS

We developed a convenient scoring system to identify patients at high risk of developing AKI after surgery for TAAAD. This scoring system may help identify patients who require more intensive postoperative management and facilitate appropriate interventions to prevent AKI and improve patient outcomes.

Acute kidney injury in patients operated on for type A acute aortic dissection: incidence, risk factors and short-term outcomes

OBJECTIVES

Acute kidney injury (AKI) is a relatively common complication after an operation for type A acute aortic dissection and is indicative of a poor prognosis. We examined the risk factors for and the outcomes of developing AKI in patients being operated on for thoracic aortic diseases.

METHODS

We retrospectively analysed 712 patients with acute type A dissection who had deep hypothermic circulatory operations from January 2014 to December 2018, emphasizing those who developed AKI. Logistic regression models were used to identify predisposing factors for the postoperative development of AKI.

RESULTS

Among all enrolled patients, 359 (50.4%) had AKI; of these, 133 were diagnosed as stage 1 (18.7%), 126 were stage 2 (17.7%) and 100 were stage 3 (14.0%). Postoperative haemodialysis was required in 111 patients (15.9%). The development of AKI after aortic surgery contributed to the higher mortality rate within 30 days after surgery (P < 0.001), longer stay in the intensive care unit (P = 0.01) and longer hospital stay (P < 0.001). Binary logistic regression analysis showed that preoperative cystatin C levels [odds ratio (OR) 2.615, 95% confidence interval (CI) 1.139-6.002; P = 0.023] and postoperative ventilation time (OR 1.019, 95% CI 1.005-1.034; P = 0.009) were independent risk factors for developing AKI. Multiple ordinal logistic regression analyses showed that the preoperative cystatin C level (OR 2.921, 95% CI 1.542-5.540; P = 0.001) was an independent risk factor associated with the severity of AKI.

CONCLUSIONS

Our data suggested that the development of AKI after surgery for type A acute aortic dissection was common and associated with an increased short-term mortality rate. The preoperative cystatin C level was identified as an indicator for the occurrence and severity of AKI postoperatively. Furthermore, we discovered that longer postoperative ventilation time was also associated with the development of AKI.

Risk factors and long-term outcomes of acute kidney injury complication after type A acute aortic dissection surgery in young patients

OBJECTIVE

To identify risk factors and long-term outcomes of acute kidney injury (AKI) in young patients who underwent type A acute aortic dissection (TA-AAD) emergency surgeries.

METHODS

This retrospective study enrolled 121 consecutive patients less than 40 years old who received TA-AAD emergency surgeries between January 2014 to December 2018 in Nanjing Drum Tower hospital. The diagnosis of AKI was made based on the KDIGO criteria. Multivariable regression analysis was performed to identify risk factors for postoperative AKI. Kaplan-Meier curves were generated to compare long-term outcomes between patients with and without AKI complication after TA-AAD surgeries.

RESULTS

Among all enrolled patients, AKI occurred in 51 patients (42.1%) and renal replacement therapy (RRT) was required in 15 patients (12.4%). The development of postoperative AKI was associated with increased 30-day mortality (P = 0.041), longer ICU stay time (P < 0.001) and hospital stay time (P = 0.006). Multivariable analysis indicated that elevated preoperative serum cystatin C (sCyC) (OR = 6.506, 95% CI: 1.852-22.855, P = 0.003) was the only independent risk factor for developing AKI. The areas under the receiver-operating characteristic curve (AUC) of preoperative sCyC was 0.800 (95% CI: 0.719, 0.882). Preoperative sCyC had a sensitivity of 64.7% and a specificity of 83.8% in diagnosing postoperative AKI with a cut-off value of 0.895 mg/L. In addition, our data suggested there was no difference discovered regarding long-term cumulative survival rate between patients with and without AKI during a median 29 months follow-up period.

CONCLUSIONS

Postoperative AKI after TA-AAD surgeries was relatively common in young patients and associated with increased short-term mortality. Elevated preoperative sCyC was identified as an independent risk factor for AKI with potential diagnostic merit.

Impact of acute kidney injury on prognosis of chronic kidney disease after aortic arch surgery

OBJECTIVES

Postoperative acute kidney injury (AKI) is a common complication associated with increased long-term mortality after cardiothoracic surgery. However, AKI after total aortic arch replacement (TAR) is not well studied. This study aimed to investigate the prognosis and impact of AKI on the long-term outcomes of chronic kidney disease (CKD) patients undergoing TAR.

METHODS

We included 208 patients who underwent TAR between September 2003 and December 2014. Patients were divided into a CKD (n = 83, 40%) and non-CKD (n = 125, 60%) group. The definition of AKI followed the Risk, Injury, Failure, Loss of kidney function and End-stage kidney disease (RIFLE) criteria. Independent risk factors for all-cause death and AKI were identified with multivariable analysis.

RESULTS

Postoperative AKI was observed in 24 patients (29%) and 39 patients (31%) of CKD and non-CKD groups, respectively. The survival rate of CKD patients was significantly lower than that of non-CKD patients (P = 0.02). Among CKD patients, the 5-year survival rate was 57% in those with AKI group and 92% in those without AKI; prognosis was significantly poorer in patients with AKI (P = 0.001). In the non-CKD group, there was no difference in prognosis between patients with or without AKI (P = 0.77). Multivariable logistic regression analysis revealed that intraoperative blood loss of ≥600 ml was the only predictor of AKI in the CKD group (odds ratio 4.32, P = 0.04).

CONCLUSIONS

CKD is associated with reduced long-term survival after TAR. Postoperative AKI strongly influences long-term survival in CKD patients only.

Risk factors analysis of acute kidney injury following open thoracic aortic surgery in the patients with or without acute aortic syndrome: a retrospective study

Background

The acute kidney injury (AKI) remains a frequent complication following open thoracic aortic surgery (OTAS) and worsens the postoperative prognosis. It remains unclear that whether the predictors of AKI following OTAS are different in the patients with or without acute aortic syndrome (AAS).

Methods

Preoperative and intraoperative variables were compared between the patients with or without AKI, and were further analyzed for identifying the potential predictors of postoperative AKI. Subgroup analysis was conducted in the patients with or without AAS, respectively.

Results

AKI after OTAS occurred in 57.6% of the overall cohort, 70.1% of the patients with AAS and 46.7% of the patients without AAS. In the multivariate analysis, history of hypertension (OR 1.011, 95% CI: [1.001–1.022], p = 0.04), preoperative platelet (OR 0.995, 95% CI: [0.991–0.999], p = 0.006) and operation time (OR 1.572, 95% CI: [1.355–1.823], p < 0.001) were identified as independent predictors of postoperative AKI for the overall cohort; CPB time (OR 1.020, 95% CI: [1.009–1.031], p < 0.001) and preoperative LMR (OR 0.823, 95% CI: [0.701–0.966], p = 0.02) as independent predictors for the patients with AAS; age (OR 1.045, 95% CI: [1.015–1.076], p = 0.003), preoperative platelet (OR 0.993, 95% CI: [0.988–0.998], p = 0.04) and operation time (OR 1.496, 95% CI: [1.166–1.918], p = 0.002) as independent predictors for the patients without AAS.

Conclusions

The patients with AAS carry a higher risk for postoperative AKI compared with those without AAS. The predictive factors for postoperative AKI after OTAS are different for AAS- and non-AAS subgroups and operation time, CPB time and preoperative platelet are modifiable predictors of AKI.

Early versus standard renal replacement therapy after left ventricular assist device implantation

OBJECTIVES

Renal function may improve after left ventricular assist device (LVAD) implant, however, some patients develop postoperative acute kidney injury (AKI). Randomized trials showed benefit for early renal replacement therapy (RRT) in critically ill patients with AKI, but this practice has not been studied in LVAD patients.

METHODS

We performed a single-center, retrospective cohort study of all adults (>18 years) who underwent LVAD placement from 1/2010 to 12/2018. We collected preoperative, hemodynamic, echocardiographic, intraoperative, and postoperative data. AKI was defined according to Kidney Disease: Improving Global Outcomes definition. Early (E) RRT was considered treatment at AKI stage II or below. Standard (S) RRT was considered treatment at AKI stage III. Outcomes and Kaplan-Meier analysis were compared between groups.

RESULTS

A total of 184 patients were included (mean age 56.10 years, 81% males, 30.4% African-American race). A total of 71 (38.6%) developed AKI and 17 (9.24%) needed RRT (11 E vs 6 S). A total of 11 remained hemodialysis-dependent at discharge (5 [45.5%] in E vs 6 [100%] in S, P = .043). There was a trend toward shorter intensive care unit stay and ventilation time in E group, and overall hospital stay was significantly less in the E group (48.18 ± 25.95 vs 94.00 ± 53.07 days, P = .028). Thirty-day mortality was similar between groups (E 18% vs S 16%, P = .9), but there was a trend toward improved overall survival in the E group.

CONCLUSION

This is the first study to examine early initiation of RRT after LVAD implant. Early RRT was associated with shorter hospital stay, lower need for permanent RRT, and a trend toward improved survival. This practice may provide significant cost savings and should be examined further.

Acute Renal Failure/Acute Kidney Injury (AKI) Associated with Endovascular Procedures

AKI is one of the most common yet underdiagnosed postoperative complications that can occur after any type of surgery. Contrast-induced nephropathy (CIN) is still poorly defined and due to a wide range of confounding individual variables, its risk is difficult to determine. CIN mainly affects patients with underlying chronic kidney disease, diabetes, sepsis, heart failure, acute coronary syndrome and cardiogenic shock. Further research is necessary to better understand pathophysiology of contrast-induced AKI and consequent implementation of effective prevention and therapeutic strategies. Although many therapies have been tested to avoid CIN, the only potent preventative strategy involves aggressive fluid administration and reduction of contrast volume. Regardless of surgical technique—open or endovascular—perioperative AKI is associated with significant morbidity, mortality and cost. Endovascular procedures always require administration of a contrast media, which may cause acute tubular necrosis or renal vascular embolization leading to renal ischemia and as a consequence, contribute to increased number of post-operative AKIs.

Preoperative platelet count, preoperative hemoglobin concentration and deep hypothermic circulatory arrest duration are risk factors for acute kidney injury after pulmonary endarterectomy: a retrospective cohort study

Background

Acute kidney injury (AKI) is a major postoperative morbidity of patients undergoing cardiac surgery and has a negative effect on prognosis. The kidney outcomes after pulmonary endarterectomy (PEA) have not yet been reported; However, several perioperative characteristics of PEA may induce postoperative AKI. The objective of our study was to identify the incidence and risk factors for postoperative AKI and its association with short-term outcomes.

Methods

This was a single-center, retrospective, observational, cohort study. Assessments of AKI diagnosis was executed based on the Kidney Disease Improving Global Outcomes (KDIGO) criteria.

Results

A total of 123 consecutive patients who underwent PEA between 2014 and 2018 were included.

The incidence of postoperative AKI was 45% in the study population. Stage 3 AKI was associated with worse short-term outcomes and 90-day mortality (p < 0.001, p = 0.002, respectively). The independent predictors of postoperative AKI were the preoperative platelet count (OR 0.992; 95%CI 0.984–0.999; P = 0.022), preoperative hemoglobin concentration (OR 0.969; 95%CI 0.946–0.993; P = 0.01) and deep hypothermic circulatory arrest (DHCA) time (OR 1.197; 95%CI 1.052–1.362; P = 0.006) in the multivariate analysis.

Conclusion

The incidence of postoperative AKI was relatively high after PEA compared with other types of cardiothoracic surgeries. The preoperative platelet count, preoperative hemoglobin concentration and DHCA duration were modifiable predictors of AKI, and patients may benefit from some low-risk, low-cost perioperative measures.

Selective Antegrade Cerebral Perfusion With or Without Additional Lower Body Perfusion During Aortic Arch Reconstruction in Infants

BACKGROUND

Aortic arch reconstruction is often challenging, especially in infants, owing to its high postoperative complication risks. This study aimed to compare the effectiveness between selective antegrade cerebral perfusion (SACP) alone and SACP in combination with continuous lower body perfusion with descending aortic cannulation (DAC) in preserving renal function, and to determine the influence of perfusion strategy on the postoperative course of infants who underwent aortic arch reconstruction.

MATERIAL AND METHODS

A total of 121 infants who underwent aortic arch reconstruction between January 2008 and December 2018 were included in the analysis. Patients (median age: 29 days, range: 3-270 days) were divided into the following groups: those who underwent repair with SACP (SACP group, 79 patients) and those who underwent additional lower body perfusion (DAC group, 42 patients).

RESULTS

Three (7.1%) and nine (11.4%) patients died in the DAC and SACP groups, respectively (P = .54). The SACP group had more patients requiring renal replacement therapy (P = .002) and higher incidence of second stage acute kidney injury (AKI) development (Kidney disease improving global outcomes (KDIGO) criteria; P = .032). The SACP group had higher frequency of open chest postoperatively than the DAC group (P = .011). The DAC group had lower vasoactive inotropic score (VIS) at the first postoperative day (P < .001) and shorter intensive care unit length of stay (P = .050). There was no difference in neurological complications between the groups (P = .061). High VIS was associated with early mortality (odds ratio [OR]: 1.79 [1.33-2.41], P < .001) and AKI (OR: 1.60 [1.35-1.91], P < .001). The DAC perfusion strategy with minimal hypothermia was associated with lower risk of AKI (OR: 0.91 [0.84-0.98], P = .016).

CONCLUSION

Antegrade cerebral perfusion with continuous lower body perfusion via DAC could effectively be used for improving early postoperative results among infants undergoing procedures that include aortic arch reconstruction.

Intraoperative renal resistive index threshold as an acute kidney injury biomarker

STUDY OBJECTIVE

The lag in creatinine-mediated diagnosis of cardiac surgery-associated acute kidney injury (AKI) may be impeding the development of renoprotection therapies. Postoperative renal resistive index (RRI) measured by transabdominal Doppler ultrasound is a promising early AKI biomarker. RRI measured intraoperatively by transesophageal echocardiography (TEE) is available even earlier but is less evaluated. Therefore, we conducted an assessment of intraoperative RRI as an AKI biomarker using previously reported post-renal insult thresholds.

DESIGN

Retrospective convenience sample.

SETTING

Intraoperative.

PATIENTS

180 adult cardiac surgical patients between July 2013 and July 2014.

INTERVENTION

None.

MEASUREMENTS

Pre- and post-cardiopulmonary bypass (CPB) RRI thresholds, measured using intraoperative TEE, exceeding 0.74 or 0.79 were used to evaluate for an association with KDIGO AKI risk using the Chi-square test. Other consensus AKI criteria (AKIN, RIFLE) were similarly evaluated. Additional t-test analyses examined the relationship of pre- and pre-to-post (delta) CPB RRI with AKI.

MAIN RESULTS

Post-CPB RRI for 99 patients included 36 and 23 with values exceeding 0.74 and 0.79, respectively. Analyses confirmed associations of both RRI thresholds with all consensus AKI definitions (0.74; KDIGO: p = 0.05, AKIN: p = 0.03, RIFLE: p = 0.03, 0.79; KDIGO: p = 0.002, AKIN: p = 0.001, RIFLE: p = 0.004). In contrast, pre-CPB and pre-to post-CPB RRI were not associated with AKI.

CONCLUSIONS

RRI obtained intraoperatively in cardiac surgery patients, assessed using previously reported thresholds, is highly associated with AKI and warrants further evaluation as a promising "earliest" AKI biomarker. These significant findings suggest that RRI assessment should be included in the standard intraoperative TEE exam.

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.

Retrograde Inferior Vena caval Perfusion for Total Aortic arch Replacement Surgery (RIVP-TARS): study protocol for a multicenter, randomized controlled trial

BACKGROUND

During total aortic arch replacement surgery (TARS) for patients with acute type A aortic dissection, the organs in the lower body, such as the viscera and spinal cord, are at risk of ischemia even when antegrade cerebral perfusion (ACP) is performed. Combining ACP with retrograde inferior vena caval perfusion (RIVP) during TARS may improve outcomes by providing the lower body with oxygenated blood.

METHODS

This study is designed as a multicenter, computer-generated, randomized controlled, assessor-blind, parallel-group study with a superiority framework in patients scheduled for TARS. A total of 636 patients will be randomized on a 1:1 basis to a moderate hypothermia circulatory arrest (MHCA) group, which will receive selective ACP with moderate hypothermia during TARS; or to an RIVP group, which will receive the combination of RIVP and selective ACP under moderate hypothermia during TARS. The primary outcome will be a composite of early mortality and major complications, including paraplegia, postoperative renal failure, severe liver dysfunction, and gastrointestinal complications. All patients will be analyzed according to the intention-to-treat protocol.

DISCUSSION

This study aims to assess whether RIVP combined with ACP leads to superior outcomes than ACP alone for patients undergoing TARS under moderate hypothermia. This study seeks to provide high-quality evidence for RIVP to be used in patients with acute type A aortic dissection undergoing TARS.

TRIAL REGISTRATION

Clinicaltrials.gov, ID: NCT03607786 . Registered on 30 July 2018.

Temperature Selection in Antegrade Cerebral Perfusion for Aortic Arch Surgery: A Meta-Analysis

BACKGROUND

The increasing use of antegrade cerebral perfusion (ACP) during aortic arch surgery has corresponded with a trend toward warmer target temperatures for hypothermic circulatory arrest. This meta-analysis examined the clinical outcomes using colder or warmer circulatory arrest targets with ACP.

METHODS

Electronic searches were performed using four databases from their inception to February 2017. Comparative studies of adult patients who underwent aortic arch operations using ACP at different circulatory arrest temperatures were included. Data were extracted by 2 independent researchers and analyzed according to predefined end points using a random-effects model.

RESULTS

The literature search identified 18 comparative studies, with 1,215 patients in the "cold" cohort and 1,417 in the "warm" cohort. Mean hypothermic circulatory arrest temperatures were 20.3°C and 26.5°C in the cold and warm groups, respectively. A trend existed for increased permanent neurologic deficit overall when colder targets were used (odds ratio, 1.45; 95% confidence interval, 0.98 to 2.13; p = 0.06); this became significant when adjusted estimates were aggregated (odds ratio, 1.65; 95% confidence interval, 1.06 to 2.55; p = 0.03). No difference in the mortality rate was seen when adjusted effects were aggregated. Temporary neurologic deficit, postoperative dialysis, ventilator time, and intensive care unit stay were significantly reduced in the warm cohort overall. No significant differences in reexploration for bleeding were found.

CONCLUSIONS

ACP with warmer circulatory arrest temperatures may reduce the incidence of permanent neurologic deficit as well as potentially other clinical outcomes. Further studies are required to determine the safe circulatory arrest durations for visceral organs at warmer temperatures.

Transient acute kidney injury after cardiac surgery does not independently affect postoperative outcomes

BACKGROUND

The objective of this study was to assess the incidence of in-hospital acute kidney injury (AKI) after cardiac surgery by comparing preoperative baseline renal function with renal function during the postoperative period and at discharge, and to relate these indices with in-hospital postoperative outcomes.

METHODS

A retrospective analysis was performed over a 4-year period from a series of 426 adult patients. Kidney function was based on serum creatinine (SCr), Cockroft-Gault estimated creatinine clearance (eCrCl), and glomerular filtration rate estimated with the Modification of Diet in Renal Disease formula (eGFR). Baseline values were compared with "peak" values of altered kidney function postoperatively, and "discharge" values. In-hospital mortality and complication rates were compared between patients with transient and persistent AKI, and those without postoperative AKI.

RESULTS

After surgery, AKI (Risk-Injury-Failure-Loss-Endstage [RIFLE] classes Injury and Failure) was diagnosed in 14.6-17.5% of patients based on peak values. AKI diagnosis was reduced to 3.6-4.5% when SCr, eCrCl, and eGFR were measured at discharge. In-hospital mortality of patients with transient AKI was 4% versus 26% in patients with AKI at discharge (odds ratio = 0.11, 95% confidence interval 0.02-0.62, P = 0.011).

CONCLUSIONS

A diagnosis of AKI based on measurements of eGFR during the postoperative period was nearly four times more frequent than the same diagnosis at discharge. Transient AKI was the predominate presentation of postoperative kidney dysfunction in this study. Transient AKI did not affect in-hospital outcomes compared with patients without AKI. Patients with persistent AKI at discharge had the highest mortality.

Epidemiology, outcomes, and management of acute kidney injury in the vascular surgery patient

OBJECTIVE

Conventional clinical wisdom has often been nihilistic regarding the prevention and management of acute kidney injury (AKI), despite its being a frequent and morbid complication associated with both increased mortality and cost. Recent developments have shown that AKI is not inevitable and that changes in management of patients can reduce both the incidence and morbidity of perioperative AKI. The purpose of this narrative review was to review the epidemiology and outcomes of AKI in patients undergoing vascular surgery using current consensus definitions, to discuss some of the novel emerging risk stratification and prevention techniques relevant to the vascular surgery patient, and to describe a standardized perioperative pathway for the prevention of AKI after vascular surgery.

METHODS

We performed a critical review of the literature on AKI in the vascular surgery patient using the PubMed and MEDLINE databases and Google Scholar through September 2017 using web-based search engines. We also searched the guidelines and publications available online from the organizations Kidney Disease: Improving Global Outcomes and the Acute Dialysis Quality Initiative. The search terms used included acute kidney injury, AKI, epidemiology, outcomes, prevention, therapy, and treatment.

RESULTS

The reported epidemiology and outcomes associated with AKI have been evolving since the publication of consensus criteria that allow accurate identification of mild and moderate AKI. The incidence of AKI after major vascular surgery using current criteria is as high as 49%, although there are significant differences, depending on the type of procedure performed. Many tools have become available to assess and to stratify the risk for AKI and to use that information to prevent AKI in the surgical patient. We describe a standardized clinical assessment and management pathway for vascular surgery patients, incorporating current risk assessment and preventive strategies to prevent AKI and to decrease its complications. Patients without any risk factors can be managed in a perioperative fast-track pathway. Those patients with positive risk factors are tested for kidney stress using the urinary biomarker TIMP-2•IGFBP7, and care is then stratified according to the result. Management follows current Kidney Disease: Improving Global Outcomes guidelines.

CONCLUSIONS

AKI is a common postoperative complication among vascular surgery patients and has a significant impact on morbidity, mortality, and cost. Preoperative risk assessment and optimal perioperative management guided by that risk assessment can minimize the consequences associated with postoperative AKI. Adherence to a standardized perioperative pathway designed to reduce risk of AKI after major vascular surgery offers a promising clinical approach to mitigate the incidence and severity of this challenging clinical problem.

Impact of Acute Kidney Injury and CKD on Adverse Outcomes in Critically Ill Septic Patients

Introduction

Chronic kidney disease (CKD) and acute kidney injury (AKI) are strongly associated with excess morbidity and mortality and frequently co-occur in critically ill septic patients, but how their interplay affects clinical outcomes is not well elucidated.

Methods

We conducted a single-center, retrospective cohort study of 2632 adult patients admitted to the intensive care unit (ICU) with severe sepsis or septic shock. Subjects were classified into 6 groups according to baseline CKD (no-CKD: estimated glomerular filtration rate [eGFR] ≥60; CKD: eGFR 15−59 ml/min per 1.73 m²) and incident AKI by the Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria (no-AKI, AKI stage 1, AKI stages ≥2) during ICU stay. Study outcomes were 90-day mortality (in hospital or within 90 days of discharge) and incident/progressive CKD.

Results

Prevalent CKD was 46% and incident AKI was 57%. Adjusted hazard ratios (95% confidence intervals) for 90-day mortality relative to the reference group of no-CKD/no-AKI were 1.5 (1.1−2.0) in no-CKD/AKI stage 1, 2.4 (1.9−3.1) in no-CKD/AKI stages≥2, 1.1 (0.8−1.4) in CKD/no-AKI, 1.2 (0.9−1.6) in CKD/AKI stage 1, and 2.2 (1.7−2.9) in CKD/AKI stages ≥2. A similar trend was observed for incident/progressive CKD during a median follow-up of 15.3 months.

Conclusion

Stage 1 AKI on CKD was not associated with an independent increased risk of adverse outcomes in critically ill septic patients. AKI stages ≥2 on CKD and any level of AKI in no-CKD patients were strongly and independently associated with adverse outcomes. Sepsis-associated stage 1 AKI on CKD may represent distinct underlying pathophysiology, with more prerenal cases and less severe de novo intrinsic damage, which needs further investigation.

Acute kidney injury in major abdominal surgery: incidence, risk factors, pathogenesis and outcomes

Acute kidney injury (AKI) is a common complication in patients undergoing major abdominal surgery. Various recent studies using modern standardized classifications for AKI reported a variable incidence of AKI after major abdominal surgery ranging from 3 to 35%. Several patient-related, procedure-related factors and postoperative complications were identified as risk factors for AKI in this setting. AKI following major abdominal surgery has been shown to be associated with poor short- and long-term outcomes. Herein, we provide a contemporary and critical review of AKI after major abdominal surgery focusing on its incidence, risk factors, pathogeny and outcomes.

Effectiveness and Safety of Aprotinin Use in Thoracic Aortic Surgery

OBJECTIVE

To determine the effectiveness and safety of aprotinin use in adult patients undergoing thoracic aortic surgery.

DESIGN

Single-center, retrospective study.

SETTING

All cases performed at a single university hospital.

PARTICIPANTS

Between January 2004 and December 2014, 846 adult patients underwent thoracic aortic surgery. Due to missing or duplicated data on primary outcomes, 314 patients were excluded. The final sample of 532 patients underwent surgery on the thoracic aorta.

INTERVENTIONS

The patients were divided in the following 2 groups: 107 patients (20.1%) received aprotinin during the surgery, which represented the study group, whereas the remaining 425 patients (79.9%) underwent surgery without the use of aprotinin.

MEASUREMENTS AND MAIN RESULTS

To adjust for patient selection and preoperative characteristics, a propensity score-matched analysis was conducted. Mean total blood loss at 12 hours after surgery was similar between the 2 groups. The blood product transfusion rates did not differ in the 2 groups, except for the rate of fresh frozen plasma transfusion being significantly higher in the aprotinin group. Re-exploration for bleeding and the incidence of a major postoperative bleeding event were similar between the groups. Rates of in-hospital mortality, renal failure, and cerebrovascular accidents did not show any statistically significant difference. Aprotinin did not represent a risk factor for mortality over the long term (hazard ratio 1.14, 95% confidence interval 0.62-2.08, p = 0.66).

CONCLUSIONS

The use of aprotinin demonstrated a limited effect in reducing postoperative bleeding and prevention of major bleeding events. Aprotinin did not adversely affect early outcomes and long-term survival.

Risk factors for continuous renal replacement therapy after surgical repair of type A aortic dissection

BACKGROUND

To identify the risk factors for continuous renal replacement therapy (CRRT) following surgical repair of type A aortic dissection (TAAD) using the total arch replacement and frozen elephant trunk (TAR + FET) technique.

METHODS

The study included 330 patients with TAAD repaired using TAR + FET between January 2014 and April 2015. Mean age was 47.1±10.2 years (range, 18-73 years) and 242 were male (73.3%). Univariate and multivariate analyses were used to identify the risk factors for CRRT.

RESULTS

Postoperative CRRT was required in 38 patients (mean age 50.7±10.0 years; 27 males). Operative death occurred in 12 patients (3.6%, 12/330). The mortality rate was 23.7% (9/38) in patients with CRRT and 1.0% (3/292) in those without CRRT (P<0.001). Factors associated with CRRT were age (50.7±10.0 vs. 46.7±10.2 years, P=0.023), preoperative serum creatinine (sCr) (135.0±154.2 vs. 85.7±37.0 µmol/L, P<0.001), emergency operation (89.5% vs. 73.3%, P=0.030), cardiopulmonary bypass (CPB) time (265.2±98.8 vs. 199.7±44.2 minutes, P<0.001), cross-clamp time (144.6±54.8 vs. 116.3±33.2 minutes, P<0.001), the amount of red blood cell (8.0±5.2 vs. 3.7±3.3 unit, P<0.001) and fresh frozen plasma (507.8±350.3 vs. 784.2±488.5 mL, P<0.001) transfused intraoperatively, preoperative D-dimmer level (11,361.0 vs. 2,856.7 mg/L, P<0.001) and reexploration for bleeding (15.8% vs. 2.4%, P<0.001). In multivariate analysis, risk factors for CRRT were CPB time (minute) [odds ratio (OR) 1.018; 95% confidence interval (CI), 1.007-1.029; P=0.002], preoperative sCr level (µmol/L) (OR, 1.008; 95% CI, 1.000-1.015; P=0.040), and the amount of red blood cell transfused intraoperatively (unit) (OR, 1.206; 95% CI, 1.077-1.350; P<0.001).

CONCLUSIONS

In this series of patients with TAAD, the time of CPB (minute), sCr level (µmol/L) and the amount of red blood cell transfused intraoperatively (unit) were risk factors for CRRT after TAR + FET.

Mortality and cost of acute and chronic kidney disease after cardiac surgery

PURPOSE OF REVIEW

Acute and chronic kidney diseases (AKI and CKD) have far-reaching implications for surgical patients in regards to postoperative outcomes and hospital cost. We review the recent literature on the effects of AKI and CKD on morbidity, mortality, and resource utilization among cardiac surgery patients.

RECENT FINDINGS

Both AKI and CKD increase the risk for short-term and long-term mortalities, morbidity, length of stay, and hospital cost among postoperative patients, with increasing disease stage correlating with worse outcomes. Even the mildest forms of AKI (RIFLE-R) and CKD (proteinuria without an observed reduction in estimated glomerular filtration rate) demonstrate worse clinical outcomes compared with patients with no AKI or CKD. Outcomes are worse even in patients who achieve full renal recovery before hospital discharge. These complications dramatically increase ICU length of stay, hospital length of stay, resource utilization, and both in-hospital and postdischarge costs, as evidenced by lower rates of discharges to home.

SUMMARY

AKI and CKD remain prevalent, morbid, and costly conditions for cardiac surgery patients. Better risk stratification, early diagnosis, and earlier interventions are needed to prevent the consequences of these diseases.

Immediate ICU Care for Patients Following Aortic Arch Surgery

Patients undergoing aortic arch surgery are at high risk for stroke, delirium, low cardiac output, respiratory failure, renal failure, and coagulopathy. A significantly higher mortality is seen in patients experiencing any of these complications when compared with those without complications. As surgical, perfusion, and anesthetic techniques improve, the incidence of major complications have decreased. A recent paradigm shift in cardiac surgery has focused on rapid postoperative recovery, and a similar change has affected the care of patients after arch surgery. Nevertheless, a small subset of patients experience significant morbidity and mortality after aortic arch surgery, and rapid identification of any organ dysfunction and appropriate supportive care is critical in these patients. In this article, the current state of postoperative care of the patient after open aortic arch surgery will be reviewed.

Preoperative assessment of the risk for multiple complications after surgery

BACKGROUND

The association between preoperative patient characteristics and the number of major postoperative complications after a major operation is not well defined.

METHODS

In a retrospective, single-center cohort of 50,314 adult surgical patients, we used readily available preoperative clinical data to model the number of major postoperative complications from none to ≥3. We included acute kidney injury; prolonged stay (>48 hours) in an intensive care unit; need for prolonged (>48 hours) mechanical ventilation; severe sepsis; and cardiovascular, wound, and neurologic complications. Risk probability scores generated from the multinomial logistic models were used to develop an online calculator. We stratified patients based on their risk of having ≥3 postoperative complications.

RESULTS

Patients older than 65 years (odds ratio 1.5, 95% confidence interval, 1.4-1.6), males (odds ratio 1.2, 95% confidence interval, 1.2-1.3), patients with a greater Charlson comorbidity index (odds ratio 3.9, 95% confidence interval, 3.6-4.2), patients requiring emergency operation (odds ratio 3.5, 95% confidence interval, 3.3.-3.7), and patients admitted on a weekend (odds ratio 1.4, 95% confidence interval, 1.3-1.5) were more likely to have ≥3 postoperative complications than they were to have none. Patients in the medium- and high-risk categories were 3.7 and 6.3 times more likely to have ≥3 postoperative complications, respectively. High-risk patients were 5.8 and 4.4 times more likely to die within 30 and 90 days of admission, respectively.

CONCLUSION

Readily available, preoperative clinical and sociodemographic factors are associated with a greater number of postoperative complications and adverse surgical outcomes. We developed an online calculator that predicts probability of developing each number of complications after a major operation.

Prediction and Prevention of Acute Kidney Injury after Cardiac Surgery

The incidence of acute kidney injury after cardiac surgery (CS-AKI) ranges from 33% to 94% and is associated with a high incidence of morbidity and mortality. The etiology is suggested to be multifactorial and related to almost all aspects of perioperative management. Numerous studies have reported the risk factors and risk scores and novel biomarkers of AKI have been investigated to facilitate the subclinical diagnosis of AKI. Based on the known independent risk factors, many preventive interventions to reduce the risk of CS-AKI have been tested. However, any single preventive intervention did not show a definite and persistent benefit to reduce the incidence of CS-AKI. Goal-directed therapy has been considered to be a preventive strategy with a substantial level of efficacy. Many pharmacologic agents were tested for any benefit to treat or prevent CS-AKI but the results were conflicting and evidences are still lacking. The present review will summarize the current updated evidences about the risk factors and preventive strategies for CS-AKI.

The Impact of Deep Versus Moderate Hypothermia on Postoperative Kidney Function After Elective Aortic Hemiarch Repair

BACKGROUND

There remains concern that moderate hypothermic circulatory arrest (MHCA) with antegrade cerebral perfusion (ACP) may provide suboptimal distal organ protection compared with deep hypothermic circulatory arrest (DHCA) with retrograde cerebral perfusion (RCP). We compared postoperative acute kidney injury (AKI) in in patients who underwent elective hemiarch repair with either DHCA/RCP or MHCA/ACP.

METHODS

This was a retrospective review of all patients undergoing elective aortic hemiarch reconstruction for aneurysmal disease between 2009 and 2014. Patients were stratified according to the use of DHCA/RCP versus MHCA/ACP. The primary outcome was the occurrence of AKI at 48 hours, as defined by the Risk, Injury, Failure, Loss, End-Stage (RIFLE ) criteria. A multivariable logistic regression identified risk factors for AKI.

RESULTS

One hundred eighteen patients who underwent ACP and 471 patients who underwent RCP were included. The mean lowest temperature was 26.4°C in patients who underwent MHCA/ACP and 17.5°C in patients who underwent DHCA/RCP. Baseline demographics were similar except that patients who underwent DHCA/RCP were more likely to have peripheral arterial disease or bicuspid aortic valves. Cardiopulmonary bypass and aortic cross-clamp times were shorter in the MHCA/ACP group. AKI occurred in 19 (16.2%) patients who underwent MHCA/ACP and 67 (14.3%) patients who underwent DHCA/RCP. Four (0.8%) patients who underwent DHCA/RCP required postoperative dialysis. In-hospital mortality tended to increase with increasing RIFLE classification (RIFLE class-0 (No AKI) = 0.41%; Risk = 1.35%, and Injury = 10.0%; p = 0.09). On multivariable analysis, the lowest temperature and cerebral perfusion strategy were not significant predictors of AKI. Lower baseline glomerular filtration rate (GFR), lower preoperative ejection fraction, and longer cardiopulmonary bypass (CPB) time were independently associated with higher AKI.

CONCLUSIONS

We applied the sensitive RIFLE criteria to examine AKI in patients undergoing elective aortic hemiarch replacement for aneurysmal disease. Baseline renal dysfunction, lower ejection fraction, and longer CPB time are independent predictors of AKI. Compared with DHCA/RCP, our data suggest that an MHCA/ACP cerebral protection strategy does not appear to be associated with worse postoperative renal outcomes.

Diabetes mellitus does not affect the incidence of acute kidney injury after cardiac surgery; a nested case-control study

BACKGROUND

Acute kidney injury (AKI) after cardiac surgery is a common complication associated with increased mortality. However, the heterogeneity of the definitions used results in high variance of incidence rates in the literature. Data on the effect of diabetes mellitus on AKI incidence in this setting are scarce. We thus aimed to compare the incidence of AKI (defined by the AKIN, RIFLE and KDIGO criteria) in diabetic vs. non-diabetic patients undergoing cardiac surgery.

METHODS

This is a nested case-control study from a cohort of patients undergoing cardiac surgery between 1/1/2013 and 30/6/2014 in a single center. Exclusion criteria were: type-1 diabetes, end-stage renal disease, death during surgery and AKI prior to surgery. We identified 199 type-2 diabetic patients and matched them for gender, age and estimated glomerular filtration rate (eGFR) to 199 non-diabetic individuals. The incidence of AKI between the two groups was compared in the total population and in subgroups according to preoperative eGFR. Univariate and multivariate logistic regression analysis were conducted to identify factors associated with AKI.

RESULTS

The incidence of AKI was moderately high, but similar between the two study groups (AKIN and KDIGO: 24.1 vs. 23.1 %; p = 0.906, RIFLE: 25.1 vs. 25,1 %; p = 1.000, in diabetics and non-diabetics respectively). A trend towards increased incidence of AKI from eGFR subgroup 1 to subgroup 3a was noted in diabetic patients (p = 0.04). No significant differences were detected between the two study groups within any eGFR subgroup studied. At multivariate analysis, age [per year increase: odds ratio (OR) 1.034, 95 % confidence interval (CI) 1.001-1.068] and duration of cardiopulmonary bypass [per minute increase: OR 1.009 (1.003-1.015)] were associated with AKI. Diabetes was not related to AKI development in regression analysis [OR 1.057 (0.666-1.679)].

CONCLUSIONS

Incidence of AKI after cardiac surgery is high, but diabetes is not a risk factor for AKI. Baseline renal function in diabetics is related inversely to the incidence of AKI. Age and cardiopulmonary bypass duration are independent predictors of cardiac surgery-associated AKI.

Postoperative acute kidney injury defined by RIFLE criteria predicts early health outcome and long-term survival in patients undergoing redo coronary artery bypass graft surgery

Objective

To investigate the impact of postoperative acute kidney injury (AKI) on early health outcome and on long-term survival in patients undergoing redo coronary artery bypass grafting (CABG).

Methods

We performed a Cox analysis with 398 consecutive patients undergoing redo CABG over a median follow-up of 7 years (interquartile range, 4-12.2 years). Renal function was assessed using baseline and peak postoperative levels of serum creatinine. AKI was defined according to the risk, injury, failure, loss, and end-stage (RIFLE) criteria. Health outcome measures included the rate of in-hospital AKI and all-cause 30-day and long-term mortality, using data from the United Kingdom's Office of National Statistics. Propensity score matching, as well as logistic regression analyses, were used. The impact of postoperative AKI at different time points was related to survival.

Results

In patients with redo CABG, the occurrence of postoperative AKI was associated with in-hospital mortality (odds ratio [OR], 3.74; 95% confidence interval [CI], −1.3 to 10.5; P < .01], high Euroscore (OR, 1.27; 95% CI, 1.07-1.52; P < .01), use of IABP (OR, 6.9; 95% CI, 2.24-20.3; P < .01), and reduced long-term survival (hazard ratio [HR], 2.42; 95% CI, 1.63-3.6; P = .01). Overall survival at 5 and 10 years was lower in AKI patients with AKI compared with those without AKI (64% vs 85% at 5 years; 51% vs 68% at 10 years). On 1:1 propensity score matching analysis, postoperative AKI was independently associated with reduced long term survival (HR, 2.8; 95% CI, 1.15-6.7).

Conclusions

In patients undergoing redo CABG, the occurrence of postoperative AKI is associated with increased 30-day mortality and major complications and with reduced long-term survival.

Acute Kidney Injury in the Surgical Patient

Perioperative acute kidney injury (AKI) is a common, morbid, and costly surgical complication. Current efforts to understand and manage AKI in surgical patients focus on prevention, mitigation of further injury when AKI has occurred, treatment of associated conditions, and facilitation of renal recovery. Lesser severity AKI is now understood to be much more common, and more morbid, than was previously thought. The ability to detect AKI within hours of onset would be helpful in protecting the kidney and in preserving renal function, and several imaging and biomarker modalities are currently being evaluated.