Correlation of cardiopulmonary bypass duration with acute renal failure after cardiac surgery

Effect of lower-body ischemia duration in aortic arch surgery under mild-to-moderate hypothermic circulatory arrest

Objectives

Aortic arch surgery is performed at increasingly higher circulatory arrest temperatures. This might affect visceral protection. We analyzed the effect of visceral ischemic time in arch surgery under mild-to-moderate hypothermia.

Methods

We divided the population into 3 groups: group 1 (visceral ischemic time ≤30 minutes), group 2 (31-60 minutes), and group 3 (>60 minutes). The link between visceral ischemic times and in-hospital outcomes, and visceral function biomarker levels were retrospectively analyzed through chi-square test, nonparametric analysis of variance, and cubic spline interpolation.

Results

From 1995 to 2023, 1325 patients underwent aortic arch surgery under circulatory arrest at our center. Mild-to-moderate hypothermia (nasopharyngeal temperature ≥25°) was used in 960 cases. There was no significant difference among the groups for in-hospital death (group 1 = 8.5%, group 2 = 13.2%, group 3 = 11.3%; P = .224), renal complications (group 1 = 13.0%, group 2 = 19.7%, group 3 = 22.6%; P = .056), and gastrointestinal complications (group 1 = 5%, group 2 = 5.5%, group 3 = 7.1%; P = .696). However, respiratory complications (group 1 = 19.4%, group 2 = 28.1%, group 3 = 21.4%; P = .027) and transient dialysis (group 1 = 2.8%, group 2 = 7.8%, group 3 = 11.3%; P = .011) were linked to longer visceral ischemic times. Groups 2 and 3 presented significantly higher levels of creatinine (P < .01), glutamic-oxaloacetic transaminase (P < .05), and glutamic pyruvic transaminase (24 and 48 hours postsurgery, P < .01). Cubic spline analysis showed that the incidence of renal complications reached a minimum at a low visceral ischemic time and then consistently increased. Respiratory complications showed a maximum incidence at approximately 50 minutes of visceral ischemic time and then subsequently decreased.

Conclusions

Mild-to-moderate hypothermia is a safe strategy for visceral organ protection regardless of visceral ischemic time. However, longer visceral ischemic times are linked to renal complications.

Association between cardiopulmonary bypass duration and early major adverse cardiovascular events after surgical repair of supravalvular aortic stenosis

Background

Patients who underwent surgical repair of supravalvular aortic stenosis (SVAS) are at high risk for postoperative major adverse cardiovascular events (MACE). This study aimed to investigate the association between cardiopulmonary bypass (CPB) duration and MACE occurring during postoperative hospitalization or within 30 days post-surgery.

Methods

Patients who underwent surgical repair of SVAS from 2002 to 2019 at Beijing Fuwai Hospital and Yunnan Fuwai Hospital were included in this study. Patients were stratified into "CPB duration >2 h" and "CPB duration ≤2 h" groups based on intraoperative CPB duration. Various statistical methodologies were employed to investigate the association between CPB duration and early postoperative MACE, including multivariate adjustment, propensity score adjustment, propensity score matching, and logistic regression based on propensity score weighting.

Results

297 participants were included and 164 were finally matched. In the propensity score-matched cohort, CPB duration was positively associated with early postoperative MACE (odds ratio = 18.13; 95% confidence interval 2.33-140.86; P = 0.006). Consistent results were obtained in the Inverse probability of treatment-weighted, standardized mortality ratio-weighted, pairwise algorithmic-weighted, and overlap-weighted models.

Conclusion

Patients with CPB duration >2 h were at a higher risk of early postoperative MACE compared to those with CPB duration ≤2 h. This emphasized the significance of minimizing CPB exposure for the prognosis of patients with SVAS.

Growth Differentiation Factor 15 as a Biomarker for Risk Stratification in the Cardiothoracic Surgery Intensive Care Unit

Growth Differentiation Factor 15 (GDF15) is an emerging biomarker that significantly increases during acute stress responses, such as infections, and is moderately elevated in chronic and inflammation-driven conditions. While evidence suggests that high levels of GDF15 in cardiac surgery are associated with worse outcomes, its utility as an evaluator of early postoperative complications remains unclear. This study aims to characterize the postoperative profile of GDF15 in patients undergoing isolated surgical aortic valve replacement, evaluating its association with short-term outcomes. Serum samples from patients undergoing cardiac surgery were collected preoperatively and at defined postoperative time points (1 h, 6 h, 12 h, 24 h, and 48 h) to measure GDF15 levels. GDF15 levels significantly increased after surgery, peaking at 6 h. A positive correlation was observed between GDF15 levels and both cardiopulmonary bypass and aortic cross-clamp times. Notably, patients who developed postoperative acute kidney injury (AKI) or required prolonged hemodynamic support had significantly higher GDF15 levels, with increased mechanical ventilation time and extended intensive care unit length of stay. Furthermore, GDF15 levels correlated with postoperative SOFA scores at 24 h after surgery. GDF15 may be a valuable biomarker for risk stratification and guiding therapeutic decisions in cardiac surgery patients. Higher GDF15 levels were significantly associated with prolonged hemodynamic support, postoperative AKI, and measures of illness severity.

Predictors of renal replacement therapy following isolated coronary artery surgery: a retrospective case-controlled study

OBJECTIVES

Severe acute kidney injury (AKI) requiring postoperative renal replacement therapy (RRT) is associated with increased morbidity and mortality rates following cardiac surgery. Our study aimed to analyze patients requiring postoperative RRT in a population undergoing isolated coronary artery surgery.

METHODS

Following exclusions, we analyzed 124 944 consecutive patients in the Polish National Registry of Cardiac Surgical Procedures (KROK Registry), scheduled for isolated coronary artery surgery between January 2010 and December 2019. Patients who underwent preoperative chronic dialysis were excluded from the study. Data of patients requiring postoperative RRT and patients without postoperative RRT were compared.

RESULTS

In the analyzed population, 1668 patients (1.3%) developed AKI requiring RRT. In-hospital mortality among patients with and without postoperative RRT was 40.1 and 1.6%, respectively ( P <0.001). Patients requiring postoperative RRT had significantly more preoperative co-morbidities and more frequent postoperative complications. Preoperative chronic renal failure and cardiogenic shock were the two most prominent independent risk factors for postoperative RRT in these patients (OR: 5.0, 95% CI: 3.9-6.4, P <0.001 and OR: 3.9, 95% CI: 2.8-5.6, P <0.001, respectively).

CONCLUSION

Severe AKI requiring postoperative RRT dramatically increases in-hospital mortality and is associated with the development of serious postoperative complications. The need for postoperative RRT is clearly associated with the presence of preoperative co-morbidities. Preoperative chronic renal failure and cardiogenic shock were particularly related to the development of this complication.

Obesity: An Independent Predictor of Acute Renal Failure After General Surgery

Background Half of Americans will have obesity, and a quarter will have severe obesity by the year 2030. Postoperative acute renal failure (ARF) is associated with increased morbidity and mortality. Given the increase in the number of patients with obesity undergoing elective surgery, we investigated the relationship between obesity and postoperative ARF after elective general surgery procedures. Methods We performed a retrospective cohort study of patients in the 2015-2019 National Surgical Quality Improvement Program database who underwent elective general surgery procedures. The primary outcome was the presence of postoperative ARF. The patient body mass index (BMI) was categorized as normal (BMI 18.5-24.9), overweight (BMI 25-29.9), obesity class 1 and 2 (BMI 30-39.9), severe obesity (BMI 40-49.9), and extreme obesity (BMI³50). Descriptive statistics and unadjusted comparisons were performed for patients who developed postoperative ARF and those who did not. Multivariable regression analyses were used to model BMI categories and postoperative ARF, adjusting for patient- and surgical-level covariates. Results Among 424,527 patients included in the study, 3638 patients (0.8%) developed ARF. Patients who developed ARF were older, had a higher BMI, and had more serious comorbidities. After risk adjustment, there was a stepwise rise in odds of developing postoperative ARF with increasing BMI categories compared to normal BMI: (overweight: OR 1.11 (95% CI 1.0-1.23), obesity class 1 and 2: OR 1.32 (95% CI 1.2-1.46), severe obesity: OR 1.45 (95% CI 1.27-1.66), and extreme obesity: OR 1.78 (95% CI 1.47-2.15)). Conclusion Obesity is independently associated with ARF after elective general surgery procedures.

Adverse renal effects associated with cardiopulmonary bypass

Cardiac surgery on cardiopulmonary bypass (CPB) is associated with postoperative renal dysfunction, one of the most common complications of this surgical cohort. Acute kidney injury (AKI) is associated with increased short-term morbidity and mortality and has been the focus of much research. There is increasing recognition of the role of AKI as the key pathophysiological state leading to the disease entities acute and chronic kidney disease (AKD and CKD). In this narrative review, we will consider the epidemiology of renal dysfunction after cardiac surgery on CPB and the clinical manifestations across the spectrum of disease. We will discuss the transition between different states of injury and dysfunction, and, importantly, the relevance to clinicians. The specific facets of kidney injury on extracorporeal circulation will be described and the current evidence evaluated for the use of perfusion-based techniques to reduce the incidence and mitigate the complications of renal dysfunction after cardiac surgery.

Pro: Individualized Optimal Perfusion Pressure-Maximizing Patient Care During Cardiopulmonary Bypass

Cardiopulmonary bypass (CPB) has revolutionized cardiac surgery but poses challenges such as hemodynamic instability and adverse clinical outcomes. Achieving optimal perfusion during CPB ensures adequate oxygen delivery to vital organs. Although mean arterial pressure is a key determinant of perfusion pressure, clear guidelines for optimal perfusion have yet to be established. Autoregulation, the organ's ability to maintain consistent blood flow, plays a vital role in perfusion. Individual variability in autoregulation responses and intraoperative factors necessitate an individualized approach to determining the autoregulation range. Continuous assessment of autoregulation during surgery allows for personalized perfusion targets, optimizing organ perfusion. Exploring techniques like multimodal intravenous anesthesia guided by electroencephalogram can enhance perfusion maintenance within the auto-regulatory range. By adopting an individualized approach to perfusion targets on CPB, we can improve outcomes and enhance patient care.

Left ventricular assist device implantation and concomitant mitral valve surgery: A systematic review and meta-analysis

BACKGROUND

The management of concomitant valvular lesions in patients undergoing left ventricular assist device (LVAD) implantation remains a topic of debate. This systematic review and meta-analysis aimed to evaluate the existing evidence on postoperative outcomes following LVAD implantation, with and without concomitant MV surgery.

METHODS

A systematic database search was conducted as per PRISMA guidelines, of original articles comparing LVAD alone to LVAD plus concomitant MV surgery up to February 2023. The primary outcomes assessed were overall mortality and early mortality, while secondary outcomes included stroke, need for right ventricular assist device (RVAD) implantation, postoperative mitral valve regurgitation, major bleeding, and renal dysfunction.

RESULTS

The meta-analysis included 10 studies comprising 32 184 patients. It revealed that concomitant MV surgery during LVAD implantation did not significantly affect overall mortality (OR:0.83; 95% CI: 0.53 to 1.29; p = 0.40), early mortality (OR:1.17; 95% CI: 0.63 to 2.17; p = 0.63), stroke, need for RVAD implantation, postoperative mitral valve regurgitation, major bleeding, or renal dysfunction. These findings suggest that concomitant MV surgery appears not to confer additional benefits in terms of these clinical outcomes.

CONCLUSION

Based on the available evidence, concomitant MV surgery during LVAD implantation does not appear to have a significant impact on postoperative outcomes. However, decision-making regarding MV surgery should be individualized, considering patient-specific factors and characteristics. Further research with prospective studies focusing on specific patient populations and newer LVAD devices is warranted to provide more robust evidence and guide clinical practice in the management of valvular lesions in LVAD recipients.

Aortic arch redo surgery: early and mid-term outcomes in 120 patients

OBJECTIVES

The aim of this study was to analyse the indications, surgical extent and results of treatment, as well as determine the risk factors for adverse outcomes after redo arch surgery.

METHODS

Between January 1996 and December 2022, 120 patients underwent aortic arch reoperations after primary proximal aortic surgery. We retrospectively analysed perioperative data, as well as early and mid-term outcomes in these patients.

RESULTS

Indications for arch reintervention included new aortic aneurysm in 34 patients (28.3%), expanding post-dissection aneurysm in 36 (30.0%), aortic graft infection in 39 (32.5%) and new aortic dissection in 9 cases. Two patients underwent reoperation due to iatrogenic complications. Thirty-one patients (25.8%) had concomitant endocarditis. In-hospital and 30-day mortality rates were 11.7% and 15.0%, respectively. Stroke was observed in 11 (9.2%) and paraplegia in 1 patient. Prior surgery due to aneurysm [odds ratio 4.5; 95% confidence interval (CI) 1.4-17.3] and critical preoperative state (odds ratio 5.9; 95% CI 1.5-23.7) were independent predictors of 30-day mortality. Overall 1- and 5-year survival was 65.8 ± 8.8% and 51.2 ± 10.6%, respectively. Diabetes mellitus (hazard ratio 2.4; 95% CI 1.0-5.1) and peripheral arterial disease (hazard ratio 4.7; 95% CI 1.1-14.3) were independent predictors of late death. The cumulative incidence of reoperations was 12.6% (95% CI 6.7-20.4%) at 5 years. Accounting for mortality as a competing event, connective tissue disorders (subdistribution hazard ratio 4.5; 95% CI 1.6-15.7) and interval between primary and redo surgery (subdistribution hazard ratio 1.04; 95% CI 1.02-1.06) were independent predictors of reoperations after redo arch surgery.

CONCLUSIONS

Despite being technically demanding, aortic arch reoperations are feasible and can be performed with acceptable results.

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.

Assessment of renal function and prevalence of acute kidney injury following coronary artery bypass graft surgery and associated risk factors: A retrospective cohort study at a tertiary care hospital in Islamabad, Pakistan

Acute kidney injury (AKI) is a sudden decline in renal function after cardiac surgery. It is characterized by a significant reduction in glomerular filtration rate, alterations in serum creatinine (S.Cr) levels, and urine output. This study aimed to retrospectively analyze a cohort of 704 patients selected using stringent inclusion and exclusion criteria. AKI was defined by an increase of 0.3 mg/dL in S.Cr levels compared to baseline. Data were collected from the hospital and analyzed using SPSS 16.0. Data analysis revealed that 22% (n = 155) of the patients developed AKI on the second post-operative day, accompanied by a substantial increase in S.Cr levels (from 1.064 ± 0.2504 to 1.255 ± 0.2673, P < .000). Age and cardiopulmonary bypass duration were identified as risk factors along with ejection fraction and days of hospital stay, contributing to the development of AKI. Early renal replacement therapy can be planned when the diagnosis of AKI is established early after surgery.

Reoperative aortic root replacement for prosthetic aortic valve endocarditis: impact of aortic graft

OBJECTIVES

Existing aortic graft complicates the surgical management of prosthetic valve endocarditis (PVE); yet, its impact has not been well studied. We compared outcomes of patients with prior aortic valve replacement (AVR) versus aortic surgery plus AVR, who underwent reoperative aortic root replacement (ARR) for PVE of the aortic valve.

METHODS

All patients who underwent reoperative ARR for PVE between 2004 and 2021 from 2 aortic centres were included. Two groups were formed based on the presence/absence of aortic graft: prior aortic surgery (AO) and prior AVR (AV) alone. Inverse propensity treatment weighting matched the groups. The Kaplan-Meier method was used to analyse long-term survival, and Fine and Gray model was used to compare the cumulative incidence of reoperation.

RESULTS

A total of 130 patients were included (AO n = 59; AV n = 71). After matching, AO patients had increased stroke incidence (12.4% vs 0.9%) and renal failure requiring dialysis (11.5% vs 2.5%). In-hospital mortality was comparable (21.5% AO and 18.6% AV). Survival over 5 years was 68.9% (56.6-83.8%) in AO and 62.7% (48.1-81.7%) in AV (P = 0.70). The cumulative incidence of reoperation was similar [AO 6.3% (0.0-13.2%) vs AV 6.1% (0.0-15.1%), P = 0.69].

CONCLUSIONS

Reoperative ARRs for prosthetic valve/graft endocarditis are high-risk procedures. AO patients had higher incidence of postoperative morbidity versus AV patients. For all patients surviving operative intervention, survival and reoperation rates over 5 years were comparable between groups.

A tool to assess nontechnical skills of perfusionists in the cardiac operating room

OBJECTIVES

This study aimed to develop the Perfusionists' Intraoperative Non-Technical Skills tool, specifically to the perfusionists' context, and test its inter-rater reliability.

METHODS

An expert panel was convened to review existing surgical nontechnical skills taxonomies and develop the Perfusionists' Intraoperative Non-Technical Skills tool. During a workshop held at a national meeting, perfusionists completed the Perfusionists' Intraoperative Non-Technical Skills ratings after watching 4 videos displaying simulated cardiac operations. Two videos showed "good performance," and 2 videos showed "poor performance." Inter-rater reliability analysis was performed and intraclass correlation coefficient was reported.

RESULTS

The final version of the Perfusionists' Intraoperative Non-Technical Skills taxonomy contains 4 behavioral categories (decision making, situation awareness, task management and leadership, teamwork and communication) with 4 behavioral elements each. Categories and elements are rated using an 8-point Likert scale ranging from 0.5 to 4.0. A total of 60 perfusionist raters were included and the comparison between rating distribution on "poor performance" and "good performance" videos yielded a statistically significant difference between groups, with a P value less than .001. A similar difference was found in all behavioral categories and elements. Reliability analysis showed moderate inter-rater reliability across overall ratings (intraclass correlation coefficient, 0.735; 95% confidence interval, 0.674-0.796; P < .001). Similar inter-rater reliability was found when raters were stratified by experience level.

CONCLUSIONS

The Perfusionists' Intraoperative Non-Technical Skills tool presented moderate inter-rater reliability among perfusionists with varied levels of experience. This tool can be used to train and assess perfusionists in relevant nontechnical skills, with the potential to enhance safety and improve surgical outcomes.

Microvascular dysfunction following cardiopulmonary bypass plays a central role in postoperative organ dysfunction

Despite significant advances in surgical technique and strategies for tissue/organ protection, cardiac surgery involving cardiopulmonary bypass is a profound stressor on the human body and is associated with numerous intraoperative and postoperative collateral effects across different tissues and organ systems. Of note, cardiopulmonary bypass has been shown to induce significant alterations in microvascular reactivity. This involves altered myogenic tone, altered microvascular responsiveness to many endogenous vasoactive agonists, and generalized endothelial dysfunction across multiple vascular beds. This review begins with a survey of in vitro studies that examine the cellular mechanisms of microvascular dysfunction following cardiac surgery involving cardiopulmonary bypass, with a focus on endothelial activation, weakened barrier integrity, altered cell surface receptor expression, and changes in the balance between vasoconstrictive and vasodilatory mediators. Microvascular dysfunction in turn influences postoperative organ dysfunction in complex, poorly understood ways. Hence the second part of this review will highlight in vivo studies examining the effects of cardiac surgery on critical organ systems, notably the heart, brain, renal system, and skin/peripheral tissue vasculature. Clinical implications and possible areas for intervention will be discussed throughout the review.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Perioperative Management of the Patient at High-Risk for Cardiac Surgery-Associated Acute Kidney Injury

Acute kidney injury (AKI) is one of the most common major complications of cardiac surgery, and is associated with increased morbidity and mortality. Cardiac surgery-associated AKI has a complex, multifactorial etiology, including numerous factors such as primary cardiac dysfunction, hemodynamic derangements of cardiac surgery and cardiopulmonary bypass, and the possibility of a large volume of blood transfusion. There are no truly effective pharmacologic therapies for the management of AKI, and, therefore, anesthesiologists, intensivists, and cardiac surgeons must remain vigilant and attempt to minimize the risk of developing renal dysfunction. This narrative review describes the current state of the scientific literature concerning the specific aspects of cardiac surgery-associated AKI, and presents it in a chronological fashion to aid the perioperative clinician in their approach to this high-risk patient group. The evidence was considered for risk prediction models, preoperative optimization, and the intraoperative and postoperative management of cardiac surgery patients to improve renal outcomes.

Concomitant surgical ablation for atrial fibrillation is associated with increased risk of acute kidney injury but improved late survival

BACKGROUND

Acute kidney injury (AKI) after cardiac surgery remains a common complication that has been associated with increased morbidity and mortality. This study implemented Kidney Disease Improving Global Outcomes criteria to evaluate renal outcomes after concomitant surgical ablation for atrial fibrillation.

METHODS

Patients with a history of atrial fibrillation who underwent elective cardiac surgery at our institution from 2008 to 2018 were retrospectively reviewed. Those with preoperative renal dysfunction were excluded. Patients were classified as those who underwent concomitant Cox-Maze IV (CMP-IV) (n = 376) or no surgical ablation (n = 498). Nearest neighbor 1:1 propensity matching was conducted on fourteen covariates. AKI was evaluated by mixed effects logistic regression analysis. Long-term survival was evaluated by proportional hazards regression.

RESULTS

Propensity matching yielded 308 patients in each group (n = 616). All preoperative variables were similar between groups. The concomitant CMP-IV group had a greater incidence of AKI: 32% (n = 99) versus 16% (n = 49), P < .001. After accounting for bypass time and nonablation operations on mixed effects analysis, concomitant CMP-IV was associated with increased risk of AKI (odds ratio, 1.89; confidence interval, 1.12-3.18; P = .017). While AKI was associated with decreased late survival (P < .001), patients who received a concomitant CMP-IV maintained superior 7-year survival to patients who received no ablation (P < .001). No patients required permanent dialysis.

CONCLUSIONS

Concomitant CMP-IV was independently associated with increased risk of AKI in the acute postoperative period. However, the long-term risks of AKI were offset by the significant survival benefit of CMP-IV. Concerns regarding new-onset renal dysfunction should not prohibit recommendation of this procedure in appropriate patients.

The early and long-term outcomes of coronary artery bypass grafting added to aortic valve replacement compared to isolated aortic valve replacement in elderly patients: a systematic review and meta-analysis

In aged population, the early and long-term outcomes of coronary revascularization (CABG) added to surgical aortic valve replacement (SAVR) compared to isolated SAVR (i-SAVR) are conflicting. To address this limitation, a meta-analysis comparing the early and late outcomes of SAVR plus CABG with i-SAVR was performed. Electronic databases from January 2000 to November 2021 were screened. Studies reporting early-term and long-term comparison between the two treatments in patients over 75 years were analyzed. The primary endpoints were in-hospital/30-day mortality and overall long-term survival. The pooled odd ratio (OR) and hazard ratio (HR) with 95% confidence interval (CI) were calculated for in-early outcome and long-term survival, respectively. Random-effect model was used in all analyses. Forty-four retrospective observational studies reporting on 74,560 patients (i-SAVR = 36,062; SAVR + CABG = 38,498) were included for comparison. The pooled analysis revealed that i-SAVR was significantly associated with lower rate of early mortality compared to SAVR plus CABG (OR = 0.70, 95% CI 0.66–0.75; p < 0.0001) and with lower incidence of postoperative acute renal failure (OR = 0.65; 95% CI 0.50–0.91; p = 0.02), need for dialysis (OR = 0.65; 95% CI 0.50–0.86; p = 0.002) and prolonged mechanical ventilation (OR = 0.57; 95% CI 0.42–0.77; p < 0.0001). Twenty-two studies reported data of long-term follow-up. No differences were reported between the two groups in long-term survival (HR = 0.95; 95% CI  0.87–1.03; p = 0.23). CABG added to SAVR is associated with worse early outcomes in terms of early mortality, postoperative acute renal failure, and prolonged mechanical ventilation. Long-term survival was comparable between the two treatments.

Artificial intelligence-based early detection of acute kidney injury after cardiac surgery

OBJECTIVES

This study aims to improve early detection of cardiac surgery-associated acute kidney injury using artificial intelligence-based algorithms.

METHODS

Data from consecutive patients undergoing cardiac surgery between 2008 and 2018 in our institution served as the source for artificial intelligence-based modeling. Cardiac surgery-associated acute kidney injury was defined according to the Kidney Disease Improving Global Outcomes criteria. Different machine learning algorithms were trained and validated to detect cardiac surgery-associated acute kidney injury within 12 hours after surgery. Demographic characteristics, comorbidities, preoperative cardiac status, intra- and postoperative variables including creatinine and hemoglobin values were retrieved for analysis.

RESULTS

From 7507 patients analyzed, 1699 patients (22.6%) developed cardiac surgery-associated acute kidney injury. The ultimate detection model, 'Detect-A(K)I', recognizes cardiac surgery-associated acute kidney injury within 12 hours with an area under the curve of 88.0%, sensitivity of 78.0%, specificity of 78.9%, and accuracy of 82.1%. The optimal parameter set includes serial changes of creatinine and hemoglobin, operative emergency, bleeding-associated variables, cardiac ischaemic time and cardiac function-associated variables, age, diuretics and active infection, chronic obstructive lung and peripheral vascular disease.

CONCLUSIONS

The 'Detect-A(K)I' model successfully detects cardiac surgery-associated acute kidney injury within 12 hours after surgery with the best discriminatory characteristics reported so far.

Risk of Renal Dysfunction Following Heart Transplantation in Patients Bridged with a Left Ventricular Assist Device

Acute renal failure (ARF) and chronic kidney disease (CKD) are associated with short- and long-term morbidity and mortality following heart transplantation (HT). We investigated the incidence and risk factors for developing ARF requiring hemodialysis (HD) and CKD following HT specifically in patients with a left ventricular assist device (LVAD). We examined the International Society for Heart and Lung Transplantation (ISHLT) Thoracic Transplant Registry for heart transplant patients between January 2000 and June 2015. We compared patients bridged with durable continuous-flow LVAD to those without LVAD support. Primary outcomes were ARF requiring HD before discharge following HT and CKD (defined as creatinine >2.5 mg/dl, permanent dialysis, or renal transplant) within 3 years. There were 18,738 patients, with 4,535 (24%) bridged with LVAD support. Left ventricular assist device patients had higher incidence of ARF requiring HD and CKD at 1 year, but no significant difference in CKD at 3 years compared to non-LVAD patients. Among LVAD patients, body mass index (BMI) (odds ratio [OR] = 1.79, p < 0.001), baseline estimated glomerular filtration rate (eGFR) (OR = 0.43, p < 0.001), and ischemic time (OR = 1.28, p = 0.014) were significantly associated with ARF requiring HD. Similarly, BMI (hazard ratio [HR] = 1.49, p < 0.001), baseline eGFR (HR = 0.41, p < 0.001), pre-HT diabetes mellitus (DM) (HR = 1.37, p = 0.011), and post-HT dialysis before discharge (HR = 3.93, p < 0.001) were significantly associated with CKD. Left ventricular assist device patients have a higher incidence of ARF requiring HD and CKD at 1 year after HT compared with non-LVAD patients, but incidence of CKD is similar by 3 years. Baseline renal function, BMI, ischemic time, and DM can help identify LVAD patients at risk of ARF requiring HD or CKD following HT.

Preoperative Creatinine Clearance and Mortality of Elective Cardiac Surgery in Hospitalization: A Secondary Analysis

Objective

It has been reported that poor renal function before surgery is related to poor prognosis. However, there is no specific discussion on the ideal value of preoperative creatinine clearance. Consequently, our primary goal is to explore the correlation between baseline creatinine clearance and short-term mortality after cardiac surgery.

Methods

We conducted a secondary data analysis based on a French cardiac surgery cohort. The cohort included 6,889 participants in a Paris university hospital from December 2005 to December 2012. The exposure variable and outcome variable used in this secondary analysis were the preoperative creatinine clearance rate and postoperative hospital mortality. Multivariate logistic regression and generalized additive models were employed.

Results

The nonlinear relationship between the preoperative creatinine clearance rate and postoperative death was observed in this study. The preoperative creatinine clearance rate was negatively correlated with postoperative mortality in the range of 8.9–78.5 in patients younger than 80 years old (odds ratio = 0.98, 95% confidence interval 0.97–0.98, in Cockcroft Gault formulae). However, this effect characteristics reaches saturation after the preoperative creatinine clearance rate exceeds 78.5 (odds ratio = 0.99, 95% confidence interval 0.98–1.00, CG). In patients with history of thromboembolic event and coronary artery disease, the saturation effect were 30.8 mL.min⁻¹ (CG) and 56.6 mL.min⁻¹(CG).

Conclusion

In the range of 8.9–78.5 (Cockcroft), an increase in preoperative creatinine clearance is associated with a decrease in postoperative mortality with patients younger than 80 years old. In patients with a history of embolism and coronary artery disease, the cut-off points of the reduction in preoperative creatinine clearance associated with a increase in postoperative mortality are 30.8 mL.min⁻¹ and 56.6 mL.min⁻¹.

Fate of the Kidneys in Patients with Post-Operative Renal Failure After Cardiac Surgery

BACKGROUND

This study evaluates the clinical and renal-related outcomes in patients with acute renal failure (ARF) following cardiac surgery.

METHODS

Index adult cardiac operations at a single institution from 2010-2018 were reviewed. Patients requiring dialysis pre-operatively were excluded. ARF was stratified as either creatinine rise (≥3-times baseline or ≥4.0 mg/dL) or post-operative dialysis. Outcomes included mortality, rates of progression to dialysis, and renal recovery. Multivariable Cox regression was used for risk-adjustment.

RESULTS

A total of 10,037 patients, including 6,275 (62.5%) isolated coronary artery bypass grafting (CABG), 2,243 (22.3%) isolated valve, and 1,519 (15.1%) CABG plus valve cases, were included. Post-operative ARF occurred in 346 (3.5%) patients, with 230 (66.5%) requiring dialysis. Survival was significantly reduced in patients with ARF at 30-days (97.9 versus 70.8%, P <0.001), 1-year (94.9 versus 48.0%, P <0.001), and 5-years (86.2 versus 38.2%, P <0.001) with more profound reductions in those requiring dialysis, findings which persisted after risk-adjustment. Progression to subsequent dialysis in the creatinine rise group was rare (n = 1). The median time to dialysis initiation in the dialysis group was 5 days (IQR 2-12 days) with a median time of dialysis dependence of 72 days (IQR 38-1229 days). Of those patients requiring postoperative dialysis, 30.9% demonstrated renal recovery.

CONCLUSIONS

Post-operative ARF and in particular the need for dialysis are associated with substantial reductions in survival that persist during longitudinal follow-up. This occurs despite the finding that patients experiencing creatinine rise only rarely progress to dialysis, and that nearly one-third of patients requiring post-operative dialysis recover renal function.

Incidence- and In-hospital Mortality-Related Risk Factors of Acute Kidney Injury Requiring Continuous Renal Replacement Therapy in Patients Undergoing Surgery for Acute Type a Aortic Dissection

Background: Few studies on the risk factors for postoperative continuous renal replacement therapy (CRRT) in a homogeneous population of patients with acute type A aortic dissection (AAAD). This retrospective analysis aimed to investigate the risk factors for CRRT and in-hospital mortality in the patients undergoing AAAD surgery and to discuss the perioperative comorbidities and short-term outcomes. Methods: The study collected electronic medical records and laboratory data from 432 patients undergoing surgery for AAAD between March 2009 and June 2021. All the patients were divided into CRRT and non-CRRT groups; those in the CRRT group were divided into the survivor and non-survivor groups. The univariable and multivariable analyses were used to identify the independent risk factors for CRRT and in-hospital mortality. Results: The proportion of requiring CRRT and in-hospital mortality in the patients with CRRT was 14.6 and 46.0%, respectively. Baseline serum creatinine (SCr) [odds ratio (OR), 1.006], cystatin C (OR, 1.438), lung infection (OR, 2.292), second thoracotomy (OR, 5.185), diabetes mellitus (OR, 6.868), AKI stage 2-3 (OR, 22.901) were the independent risk factors for receiving CRRT. In-hospital mortality in the CRRT group (46%) was 4.6 times higher than in the non-CRRT group (10%). In the non-survivor (n = 29) and survivor (n = 34) groups, New York Heart Association (NYHA) class III-IV (OR, 10.272, P = 0.019), lactic acidosis (OR, 10.224, P = 0.019) were the independent risk factors for in-hospital mortality in patients receiving CRRT. Conclusion: There was a high rate of CRRT requirement and high in-hospital mortality after AAAD surgery. The risk factors for CRRT and in-hospital mortality in the patients undergoing AAAD surgery were determined to help identify the high-risk patients and make appropriate clinical decisions. Further randomized controlled studies are urgently needed to establish the risk factors for CRRT and in-hospital mortality.

The impact of team familiarity on intra and postoperative cardiac surgical outcomes

BACKGROUND

Familiarity among cardiac surgery team members may be an important contributor to better outcomes and thus serve as a target for enhancing outcomes.

METHODS

Adult cardiac surgical procedures (n = 4,445) involving intraoperative providers were evaluated at a tertiary hospital between 2016 and 2020. Team familiarity (mean of prior cardiac surgeries performed by participating surgeon/nonsurgeon pairs within 2 years before the operation) were regressed on cardiopulmonary bypass duration (primary-an intraoperative measure of care efficiency) and postoperative complication outcomes (major morbidity, mortality), adjusting for provider experience, surgeon 2-year case volume before the surgery, case start time, weekday, and perioperative risk factors. The relationship between team familiarity and outcomes was assessed across predicted risk strata.

RESULTS

Median (interquartile range) cardiopulmonary bypass duration was 132 (91-192) minutes, and 698 (15.7%) patients developed major postoperative morbidity. The relationship between team familiarity and cardiopulmonary bypass duration significantly differed across predicted risk strata (P = .0001). High (relative to low) team familiarity was associated with reduced cardiopulmonary bypass duration for medium-risk (-24 minutes) and high-risk (-27 minutes) patients. Increasing team familiarity was not significantly associated with the odds of major morbidity and mortality.

CONCLUSION

Team familiarity, which was predictive of improved intraoperative efficiency without compromising major postoperative outcomes, may serve as a novel quality improvement target in the setting of cardiac surgery.

Assessment of Cardiopulmonary Bypass Duration Improves Novel Biomarker Detection for Predicting Postoperative Acute Kidney Injury after Cardiovascular Surgery

Urinary liver-type fatty acid binding protein (L-FABP) is a novel biomarker with promising performance in detecting kidney injury. Previous studies reported that L-FABP showed moderate discrimination in patients that underwent cardiac surgery, and other studies revealed that longer duration of cardiopulmonary bypass (CPB) was associated with a higher risk of postoperative acute kidney injury (AKI). This study aims to examine assessing CPB duration first, then examining L-FABP can improve the discriminatory ability of L-FABP in postoperative AKI. A total of 144 patients who received cardiovascular surgery were enrolled. Urinary L-FABP levels were examined at 4 to 6 and 16 to 18 h postoperatively. In the whole study population, the AUROC of urinary L-FABP in predicting postoperative AKI within 7 days was 0.720 at 16 to 18 h postoperatively. By assessing patients according to CPB duration, the urinary L-FABP at 16 to 18 h showed more favorable discriminating ability with AUROC of 0.742. Urinary L-FABP exhibited good performance in discriminating the onset of AKI within 7 days after cardiovascular surgery. Assessing postoperative risk of AKI through CPB duration first and then using urinary L-FABP examination can provide more accurate and satisfactory performance in predicting postoperative AKI.

Aortic valve replacement using stented or sutureless/rapid deployment prosthesis via either full-sternotomy or a minimally invasive approach: a network meta-analysis

Background

New technologies such as sutureless or rapid deployment prosthetic valves and access via minimally invasive incisions offer alternatives to traditional full-sternotomy aortic valve replacement (SAVR). However, a comprehensive comparison of these surgical techniques along with alternative valve prosthesis has not been completed.

Methods

Electronic databases were searched for studies comparing outcomes for SAVR, minimally invasive AVR (MiAVR), sutureless/rapid-deployment AVR (SuAVR) via full-sternotomy, or minimally invasive SuAVR (MiSuAVR) from their inception until September 2018. Early postoperative outcomes and follow-up data were included in a Bayesian network meta-analysis.

Results

Twenty-three studies with 8,718 patients were identified. Compared with standard SAVR, SuAVR had significantly lower incidence of postoperative AF [odds ratio (OR) 0.33, 95% confidence interval (CI): 0.14-0.79, P=0.013] and MiSuAVR greater requirement for postoperative permanent pacemaker (OR 2.27, 95% CI: 1.25-4.14, P=0.008). All sutureless/rapid-deployment procedures had reduced cardiopulmonary bypass and cross-clamp times, by a mean of 25.9 and 25.0 min, respectively. Hospital length of stay (LOS), but not intensive care LOS, was reduced for all groups (MiAVR -1.53 days, MiSuAVR -2.79 days, and SuAVR 3.37 days). A signal towards reduced early mortality, wound infections, and acute kidney injury was noted in both sutureless/rapid-deployment and minimally invasive techniques but did not achieve significance. Sutureless/rapid-deployment procedures had favourable survival and freedom from valve related reoperation, however follow-up times were short and demonstrated significant heterogeneity between intervention groups.

Conclusions

Minimally invasive and sutureless techniques demonstrate equivalent early postoperative outcomes to SAVR and may reduce ventilation time, hospital LOS and postoperative atrial fibrillation (POAF) burden.

Renal Outcome in Patients Undergoing Cardiac Surgery Using Cardiopulmonary Bypass

Introduction Renal dysfunction is a significant variable in determining the outcome of surgery, such as cardiopulmonary bypass graft and valvular replacement, used to treat cardiovascular diseases. In Saudi Arabia, the incidence of renal failure and diabetes is higher than in most western populations. Our aim is to determine the renal outcome of patients who underwent cardiac surgery at King Faisal Cardiac Center from 2014 to 2017. Methods This a retrospective cohort study using a non-probability consecutive sampling technique for selection of the study population to assess the renal outcome in cardiac surgery patients using cardiopulmonary bypass from May 2014 to June 2017 in King Faisal Cardiac Center, Jeddah. Patients older than 18 years of age undergoing cardiac surgery, with available data, were included. Categorical variables were summarized by percentages and frequencies, and continuous variables by means and standard deviations, or medians and interquartile ranges if their distributions were skewed. Logistic regression was done with post-op renal impairment as the dependent variable and pre-op renal dysfunction, age, gender, smoking status, diabetes, hypertension, dyslipidemia, and cardiopulmonary bypass time as independent variables. Results Our sample size included 244 patients who underwent cardiac surgery in this study period; their mean age was 60.5 (SD =7.5) with a mean body mass index (BMI) of 28.62 (SD=5.19). Among our population, 73% (n = 179) were males and 27% (n =66) were females. Two percent (2%) of patients (n = 5) died within 30 days, 4% of patients (n = 10) with temporary dialysis, 8% of patients (n = 19) with postoperative renal dysfunction, and no patients with permanent dialysis. The data showed a significant relationship between levels of creatinine preoperatively and postoperative renal dysfunction (p-value = 0.0001, OR=1.05, 95% CI of 1.031 to 1.064). Conclusion The main predictor of poor renal outcomes for cardiac surgery is preoperative creatinine. While other factors, such as age, gender, body mass index, cardiopulmonary bypass time, diabetes, hypertension, and dyslipidemia, did not show any risk to the postoperative renal outcome.

Risk factor for acute kidney injury in patients with chronic kidney disease receiving valve surgery with cardiopulmonary bypass

INTRODUCTION

Acute kidney injury (AKI) after cardiopulmonary bypass (CPB) in patients with pre-existing impaired renal function carries deleterious outcomes but is not frequently evaluated. The optimal CPB strategy for preventing AKI in this vulnerable patient group is still controversial.

METHODS

A total of 156 patients with preoperative estimated glomerular filtration rate (e-GFR) <30 ml/min but not on chronic dialysis receiving valve operation under CPB were included in the present study. Postoperative AKI was defined as KDIGO (Kidney Disease Improving Global Outcomes) stage 3. Hospital mortality and two-year renal function evolution were compared between patients with postoperative AKI and those without AKI. Risk factors for the development of postoperative AKI were also studied.

RESULTS

The incidence of postoperative KDIGO-3 was high (44.2%). Hospital mortality was higher in the AKI group (30.4%) than in the non-AKI group (8.0%). Among the hospital survivors, renal function deterioration to permanent dialysis at two years was also more common in AKI group (14.5%) than in non-AKI group (4.6%). Univariate logistic regression for postoperative AKI revealed male gender, increased age, height, weight, BSA, and BMI, high preoperative serum creatinine, prolonged CPB duration, and decreased CPB target temperature as risk factors. However, multivariate analysis revealed only high preoperative serum creatinine and decreased CPB target temperature as significant risk factors for postoperative AKI.

CONCLUSION

To prevent postoperative AKI in CKD patients, low CPB target temperature is avoided, especially for those with high preoperative serum creatinine levels.

Association between cardiopulmonary bypass time and 90-day post-operative mortality in patients undergoing arch replacement with the frozen elephant trunk: a retrospective cohort study

BACKGROUND

The aortic arch replacement and cardiopulmonary bypass (CPB) are both associated with the early mortality after cardiothoracic surgery. This study aimed to investigate the relationship between CPB time and 90-day post-operative mortality in patients undergoing aortic arch surgery using the frozen elephant trunk (FET) technique with selective ante-grade cerebral perfusion (SACP).

METHODS

We retrospectively reviewed data of 377 adult patients undergoing aortic arch surgery via FET with SACP from July 1, 2017 to December 31, 2018 at Beijing Anzhen Hospital. The baseline characteristics, intra-operative data, and post-operative data were collected. Univariate and multivariate Cox regression analyses were used to determine independent predictors of 90-day post-operative mortality.

RESULTS

The 90-day post-operative mortality was 13.53%. The 78.51% of patients were men. There were 318 (84.35%) type A aortic dissections and 28 (7.43%) aortic aneurysms. Among those, 264 (70.03%) were emergency operations. Median CPB time was 202.0 (176.0, 227.0) min. Multivariate Cox regression analysis revealed that CPB time was independently associated with 90-day post-operative mortality after adjusting confounding factors (hazard ratio: 1.21/10 min increase in CPB time, 95% confidence interval: 1.15-1.27, P < 0.001). Kaplan-Meier analysis based on CPB time tertiles revealed that the top tertile (median 236.0 min) was associated with reduced survival rate compared with middle and bottom tertiles (P < 0.001). Each sub-group analysis based on the complexity of the underlying disease process showed similar associations between CPB time and 90-day post-operative mortality.

CONCLUSIONS

CPB time remains a significant factor in determining 90-day post-operative mortality in patients undergoing aortic arch surgery using FET with SACP. Surgeons should be aware of the relationship between CPB time and 90-day post-operative mortality during operative procedures and avoid extended CPB time as far as possible.

Iron Chelation as a Potential Therapeutic Strategy for AKI Prevention

AKI remains a major public health concern. Despite years of investigation, no intervention has been demonstrated to reliably prevent AKI in humans. Thus, development of novel therapeutic targets is urgently needed. An important role of iron in the pathophysiology of AKI has been recognized for over three decades. When present in excess and in nonphysiologic labile forms, iron is toxic to the kidneys and multiple other organs, whereas iron chelation is protective across a broad spectrum of insults. In humans, small studies have investigated iron chelation as a novel therapeutic strategy for prevention of AKI and extrarenal acute organ injury, and have demonstrated encouraging initial results. In this review, we examine the existing data on iron chelation for AKI prevention in both animal models and human studies. We discuss practical considerations for future clinical trials of AKI prevention using iron chelators, including selection of the ideal clinical setting, patient population, iron chelating agent, and dosing regimen. Finally, we compare the key differences among the currently available iron chelators, including pharmacokinetics, routes of administration, and adverse effects.