Short, and long-term mortality among cardiac intensive care unit patients started on continuous renal replacement therapy

Data-driven prediction of continuous renal replacement therapy survival

Continuous renal replacement therapy (CRRT) is a form of dialysis prescribed to severely ill patients who cannot tolerate regular hemodialysis. However, as the patients are typically very ill to begin with, there is always uncertainty whether they will survive during or after CRRT treatment. Because of outcome uncertainty, a large percentage of patients treated with CRRT do not survive, utilizing scarce resources and raising false hope in patients and their families. To address these issues, we present a machine learning-based algorithm to predict short-term survival in patients being initiated on CRRT. We use information extracted from electronic health records from patients who were placed on CRRT at multiple institutions to train a model that predicts CRRT survival outcome; on a held-out test set, the model achieves an area under the receiver operating curve of 0.848 (CI = 0.822-0.870). Feature importance, error, and subgroup analyses provide insight into bias and relevant features for model prediction. Overall, we demonstrate the potential for predictive machine learning models to assist clinicians in alleviating the uncertainty of CRRT patient survival outcomes, with opportunities for future improvement through further data collection and advanced modeling.

Invasive mechanical ventilation in cardiogenic shock complicating acute myocardial infarction: A contemporary Danish cohort analysis

PURPOSE

Invasive mechanical ventilation (IMV) is widely used in patients with cardiogenic shock following acute myocardial infarction (AMICS), but evidence to guide practice remains sparse. We sought to evaluate trends in the rate of IMV utilization, applied settings, and short term-outcome of a contemporary cohort of AMICS patients treated with IMV according to out-of-hospital cardiac arrest (OHCA) at admission.

METHODS

Consecutive AMICS patients receiving IMV in an intensive care unit (ICU) at two tertiary centres between 2010 and 2017. Data were analysed in relation to OHCA.

RESULTS

A total of 1274 mechanically ventilated AMICS patients were identified, 682 (54%) with OHCA. Frequency of IMV increased during the study period, primarily due to higher occurrence of OHCA admissions. Among 566 patients with complete ventilator data, positive-end-expiratory pressure, inspired oxygen fraction, and minute ventilation during the initial 24 h in ICU were monitored. No differences were observed between 30-day survivors and non-survivors with OHCA. In non-OHCA, these ventilator requirements were significantly higher among 30-day non-survivors (P for all<0.05), accompanied by a lower PaO2/FiO2 ratio (median 143 vs. 230, P < 0.001) and higher arterial lactate levels (median 3.5 vs. 1.5 mmol/L, P < 0.001) than survivors. Physiologically normal PaO2 and pCO2 levels were achieved in all patients irrespective of 30-day survival and OHCA status.

CONCLUSION

In the present contemporary cohort of AMICS patients, physiologically normal blood gas values were achieved both in OHCA and non-OHCA in the early phase of admission. However, increased demand of ventilatory support was associated with poorer survival only in non-OHCA patients.

Mortality associated with the neutrophil-lymphocyte ratio in septic acute kidney injury requiring continuous renal replacement therapy

BACKGROUND

Sepsis is an important cause of acute kidney injury in intensive care unit patients, accounting for 15% to 20% of renal replacement therapy prescriptions. The neutrophil-lymphocyte ratio (NLR), a marker of systemic inflammation and immune response, was previously associated with the mortality rate in multiple conditions. Herein, we aimed to examine how the NLR relates to the mortality rate in septic acute kidney injury patients requiring continuous renal replacement therapy (CRRT).

METHODS

The NLRs of 6 and 18 were used for dividing NLRs into three groups and, thus, were set higher than those in previous studies accounting for steroid use in sepsis. Cox proportional hazard models were used to calculate hazard ratios of mortality outcomes before and after matching their propensity scores.

RESULTS

A total of 798 septic acute kidney injury patients requiring CRRT were classified into three NLR groups (low, <6 [n = 277]; medium, ≥6 and <18 [n = 115], and high, ≥18 [n = 406], respectively). The in-hospital mortality rates per group were 83.4%, 74.8%, and 70.4%, respectively (p < 0.001). Per the univariable Cox survival analysis after propensity score matching, a high NLR was related to approximately 24% reduced mortality. The survival benefit of the high NLR group compared with the other two groups remained consistent across all subgroups, showing any p for interactions of >0.05.

CONCLUSION

A high NLR is associated with better clinical outcomes, such as low mortality, in septic acute kidney injury patients undergoing CRRT.

The Changing Epidemiology of the Cardiac Intensive Care Unit

Coronary care units (CCUs) were originally designed to monitor and treat peri-infarction ventricular arrhythmias but have evolved into highly specialized cardiac intensive care units (CICUs) that provide care to a patient population that is increasingly heterogeneous and complex. Paralleling broader epidemiologic trends, patients admitted to contemporary CICUs are older and have a greater burden of cardiovascular and non-cardiovascular comorbidities. Moreover, contemporary CICU patients have high illness severity and often present with acute noncardiac organ dysfunction. In addition to these shifting demographic patterns, there have been important epidemiologic changes in CICU technologies, multidisciplinary systems of care, and physician staffing and training.

Axillary mechanical circulatory support improves renal function prior to heart transplantation in patients with chronic kidney disease

Impaired kidney function is often associated with acute decompensation of chronic heart failure and portends a poor prognosis. Unfortunately, current data have demonstrated worse survival in patients with acute kidney injury than in patients with chronic kidney disease during durable LVAD placement as bridge therapy. Furthermore, end-stage heart failure patients undergoing combined heart-kidney transplantation have poorer short- and long-term survival than heart transplants alone. We evaluated the kidney function recovery in our heart failure population awaiting heart transplantation at our institution, supported by temporary Mechanical Circulatory Support (tMCS) with Impella 5.5. The protocol (#22004000) was approved by the Mayo Clinic institutional review board, after which we performed a retrospective review of all patients with acute on chronic heart failure and kidney disease in patients considered for only heart and kidney combined organ transplant and supported by tMCS between January 2020 and February 2021. Hemodynamic and kidney function trends were recorded and analyzed before and after tMCS placement and transplantation. After placement of tMCS, we observed a trend towards improvement in creatinine, Fick cardiac index, mixed venous saturation, and glomerular filtration rate (GFR), which persisted through transplantation and discharge. The average duration of support with tMCS was 16.5 days before organ transplantation. The median pre-tMCS creatinine was 2.1 mg/dL (IQR 1.75-2.3). Median hematocrit at the time of tMCS placement was 32% (IQR 32-34), and the median estimated glomerular filtration rate was 34 mL/min/BSA (34-40). The median GFR improved to 44 mL/min/BSA (IQR 45-51), and serum creatinine improved to 1.5 mg/dL (1.5-1.8) after tMCS. Median discharge creatinine was 1.1 mg/dL (1.19-1.25) with a GFR of 72 (65-74). None of these six patients supported with tMCS required renal replacement therapy after heart transplantation. Early adoption of Impella 5.5 in this patient population resulted in renal recovery without needing renal replacement therapies or dual organ transplantation and should be further evaluated.

Consulting to nephrologist when starting continuous renal replacement therapy for acute kidney injury is associated with a survival benefit

BACKGROUND

Several studies suggest improved outcomes for patients with kidney disease who consult a nephrologist. However, it remains undetermined whether a consultation with a nephrologist is related to a survival benefit after starting continuous renal replacement therapy (CRRT) due to acute kidney injury (AKI).

METHODS

Data from 2,397 patients who started CRRT due to severe AKI at Seoul National University Hospital, Korea between 2010 and 2020 were retrospectively collected. The patients were divided into two groups according to whether they underwent a nephrology consultation regarding the initiation and maintenance of CRRT. The Cox proportional hazards model was used to calculate the hazard ratio (HR) of mortality during admission to the intensive care unit after adjusting for multiple variables.

RESULTS

A total of 2,153 patients (89.8%) were referred to nephrologists when starting CRRT. The patients who underwent a nephrology consultation had a lower mortality rate than those who did not have a consultation (HR = 0.47 [0.40-0.56]; P < 0.001). Subsequently, patients who had nephrology consultations were divided into two groups (i.e., early and late) according to the timing of the consultation. Both patients with early and late consultation had lower mortality rates than patients without consultations, with HRs of 0.45 (0.37-0.54) and 0.51 (0.42-0.61), respectively.

CONCLUSIONS

Consultation with a nephrologist may contribute to a survival benefit after starting CRRT for AKI.

Echocardiographic parameters and hemodynamic instability at the initiation of continuous kidney replacement therapy

OBJECTIVE

Investigate the association of echocardiographic parameters with hemodynamic instability after initiating continuous kidney replacement therapy (CKRT) in a cohort of intensive care unit (ICU) patients requiring CKRT.

METHODS

Historical cohort study of consecutive adults admitted to the ICU at a tertiary care hospital from December 2006 through November 2015 who underwent CKRT and had an echocardiogram done within seven days before CKRT initiation. The primary outcome was hypotension within one hour of CKRT initiation.

RESULTS

We included 980 patients, 804 (82%) with acute kidney injury (AKI) and 176 (18%) with end-stage kidney disease (ESKD). Median patient age was 63 (± 14) years, and median Sequential Organ Failure Assessment (SOFA) score on the day of CKRT initiation was 12 (IQR 10-14). Multivariable analysis showed that Left (OR 2.01, 95% CI 1.04-3.86), and Right (OR 1.5, 95% CI 1.04-2.25) moderate and severe ventricular enlargement, Vasoactive-Inotropic Score (VIS) one hour before CKRT initiation (OR 1.18 per 10 units increase, 95% CI 1.09-1.28) and high bicarbonate fluid replacement (OR 2.52, 95% CI 1.01-6.2) were associated with hypotension after CKRT initiation.

CONCLUSION

Right and left ventricular enlargement are risk factors associated with hypotension after CKRT initiation.

Cardiogenic shock severity and mortality in patients receiving venoarterial extracorporeal membrane oxygenator support

AIMS

Shock severity predicts mortality in patients with cardiogenic shock (CS). We evaluated the association between pre-cannulation Society for Cardiovascular Angiography and Intervention (SCAI) shock classification and mortality among patients receiving venoarterial (VA) extracorporeal membrane oxygenation (ECMO) support for CS.

METHODS AND RESULTS

We included Extracorporeal Life Support Organization (ELSO) Registry patients from 2010 to 2020 who received VA ECMO for CS. SCAI shock stage was assigned based on hemodynamic support requirements prior to ECMO initiation. In-hospital mortality was analyzed using multivariable logistic regression. We included 12 106 unique VA ECMO patient runs with a median age of 57.9 (interquartile range: 46.8, 66.1) years and 31.8% were females; 3472 (28.7%) were post-cardiotomy. The distribution of SCAI shock stages at ECMO initiation was: B, 821 (6.8%); C, 7518 (62.1%); D, 2973 (24.6%); and E, 794 (6.6%). During the index hospitalization, 6681 (55.2%) patients died. In-hospital mortality increased incrementally with SCAI shock stage (adjusted OR: 1.24 per SCAI shock stage, 95% CI: 1.17-1.32, P < 0.001): B, 47.5%; C, 52.8%; D, 60.8%; E, 65.1%. A higher SCAI shock stage was associated with increased in-hospital mortality in key subgroups, although the SCAI shock classification was only predictive of mortality in non-surgical (medical) CS and not in post-cardiotomy CS.

CONCLUSION

The severity of shock prior to cannulation is a strong predictor of in-hospital mortality in patients receiving VA ECMO for CS. Using the pre-cannulation SCAI shock classification as a risk stratification tool can help clinicians refine prognostication for ECMO recipients and guide future investigations to improve outcomes.

Longitudinal trajectory of acidosis and mortality in acute kidney injury requiring continuous renal replacement therapy

BACKGROUND

Acidosis frequently occurs in severe acute kidney injury (AKI), and continuous renal replacement therapy (CRRT) can control this pathologic condition. Nevertheless, acidosis may be aggravated; thus, monitoring is essential after starting CRRT. Herein, we addressed the longitudinal trajectory of acidosis on CRRT and its relationship with worse outcomes.

METHODS

The latent growth mixture model was applied to classify the trajectories of pH during the first 24 hours and those of C-reactive protein (CRP) after 24 hours on CRRT due to AKI (n = 1815). Cox proportional hazard models were used to calculate hazard ratios of all-cause mortality after adjusting multiple variables or matching their propensity scores.

RESULTS

The patients could be classified into 5 clusters, including the normally maintained groups (1st cluster, pH = 7.4; and 2nd cluster, pH = 7.3), recovering group (3rd cluster with pH values from 7.2 to 7.3), aggravating group (4th cluster with pH values from 7.3 to 7.2), and ill-being group (5th cluster, pH < 7.2). The pH clusters had different trends of C-reactive protein (CRP) after 24 hours; the 1st and 2nd pH clusters had lower levels, but the 3rd to 5th pH clusters had an increasing trend of CRP. The 1st pH cluster had the best survival rates, and the 3rd to 5th pH clusters had the worst survival rates. This survival difference was significant despite adjusting for other variables or matching propensity scores.

CONCLUSIONS

Initial trajectories of acidosis determine subsequent worse outcomes, such as mortality and inflammation, in patients undergoing CRRT due to AKI.

Development and Validation of a Prognostic Model to Predict the Risk of In-hospital Death in Patients With Acute Kidney Injury Undergoing Continuous Renal Replacement Therapy After Acute Type a Aortic Dissection

Background

This study aimed to construct a model to predict the risk of in-hospital death in patients with acute renal injury (AKI) receiving continuous renal replacement therapy (CRRT) after acute type A aortic dissection (ATAAD) surgery.

Methods

We reviewed the data of patients with AKI undergoing CRRT after ATAAD surgery. The patients were divided into survival and nonsurvival groups based on their vital status at hospital discharge. The data were analyzed using univariate and multivariate logistic regression analyses. Establish a risk prediction model using a nomogram and its discriminative ability was validated using C statistic and the receiver operating characteristic (ROC) curve. Its calibration ability was tested using a calibration curve, 10-fold cross-validation and Hosmer–Lemeshow test.

Results

Among 175 patients, in-hospital death occurred in 61 (34.9%) patients. The following variables were incorporated in predicting in-hospital death: age > 65 years, lactic acid 12 h after CRRT, liver dysfunction, and permanent neurological dysfunction. The risk model revealed good discrimination (C statistic = 0.868, 95% CI: 0.806–0.930; a bootstrap-corrected C statistic of 0.859, the area under the ROC = 0.868). The calibration curve showed good consistency between predicted and actual probabilities (via 1,000 bootstrap samples, mean absolute error = 2.2%; Hosmer–Lemeshow test, P = 0.846). The 10-fold cross validation of the nomogram showed that the average misdiagnosis rate was 16.64%.

Conclusion

The proposed model could be used to predict the probability of in-hospital death in patients undergoing CRRT for AKI after ATAAD surgery. It had the potential to assist doctors to identify the gravity of the situation and make the targeted therapeutic measures.

A novel nomogram for predicting 3-year mortality in critically ill patients after coronary artery bypass grafting

Background

The long-term outcomes for patients after coronary artery bypass grafting (CABG) have been received more and more concern. The existing prediction models are mostly focused on in-hospital operative mortality after CABG, but there is still little research on long-term mortality prediction model for patients after CABG.

Objective

To develop and validate a novel nomogram for predicting 3-year mortality in critically ill patients after CABG.

Methods

Data for developing novel predictive model were extracted from Medical Information Mart for Intensive cart III (MIMIC-III), of which 2929 critically ill patients who underwent CABG at the first admission were enrolled.

Results

A novel prognostic nomogram for 3-year mortality was constructed with the seven independent prognostic factors, including age, congestive heart failure, white blood cell, creatinine, SpO₂, anion gap, and continuous renal replacement treatment derived from the multivariable logistic regression. The nomogram indicated accurate discrimination in primary (AUC: 0.81) and validation cohort (AUC: 0.802), which were better than traditional severity scores. And good consistency between the predictive and observed outcome was showed by the calibration curve for 3-year mortality. The decision curve analysis also showed higher clinical net benefit than traditional severity scores.

Conclusion

The novel nomogram had well performance to predict 3-year mortality in critically ill patients after CABG. The prediction model provided valuable information for treatment strategy and postdischarge management, which may be helpful in improving the long-term prognosis in critically ill patients after CABG.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01408-8.

Outcomes of Continuous Renal Replacement Therapy in a Community Health System

OBJECTIVE

Continuous renal replacement therapy (CRRT) is commonly used in critically ill, hemodynamically unstable patients with acute kidney injury (AKI). This procedure is resource intensive with reported high in-hospital mortality. We evaluated mortality with CRRT in our healthcare system and markers associated with decreased survival.

METHODS

A retrospective cohort study collected data on patients 18 years or older, without prior history of end stage kidney disease (ESKD), who received CRRT in the intensive care units at one of three hospitals in our health system in Columbus, OH from July 1, 2016 to July 1, 2019. Data included demographics, presenting diagnosis, comorbidities, laboratory markers, and patient disposition. In-hospital mortality rates and sequential organ failure assessment (SOFA) scores were calculated. We then compared information between two groups (patients who died during hospitalization and survivors) using univariate comparisons and multivariate logistic regression models.

RESULTS

In-hospital mortality was 56.8% (95%CI: 53.4-60.1) among patients who received CRRT. Mean SOFA scores did not differ between survival and mortality groups. The odds for in-patient mortality were increased for patients age ≥60 (OR = 1.74, 95%CI: 1.23-2.44), first bilirubin >2 mg/dL (OR = 1.73, 95%CI: 1.12-2.69), first creatinine < 2 mg/dL (OR = 1.57, 95%CI: 1.04-2.37), first lactate > 2 mmol/L (OR = 2.08, 95%CI: 1.43-3.04). The odds for in-patient mortality were decreased for patients with cardiogenic shock (OR = .32, 95%CI: .17-.58) and hemorrhagic shock (OR = .29, 95%CI: .13-.63).

CONCLUSIONS

We report in-hospital mortality rates of 56.8% with CRRT. Unlike prior studies, higher mean SOFA scores were not predictive of higher in-hospital mortality in patients utilizing CRRT.

Association Between the Neutrophil Percentage-to-Albumin Ratio and Outcomes in Cardiac Intensive Care Unit Patients

Background

The neutrophil percentage-to-albumin ratio (NPAR) is a systemic inflammation-based predictor associated with many diseases' outcomes. Nevertheless, there are few studies on the relationship between NPAR and inflammatory markers, and more importantly, the prognostic value of NPAR in critically ill patients with cardiovascular disease (CVD) remains unknown.

Methods

The data of this retrospective cohort study were from the Medical Information Mart data for Intensive Care III database (MIMIC-III) and the Second Affiliated Hospital of Wenzhou Medical University. Linear regression, logistic regression model, and Cox regression model were used to assess the associations between NPAR levels and length of stay, renal replacement therapy (RRT) use, and 30-day, 90-day and one-year mortality, respectively. The Pearson correlation coefficient was used to present the correlation between NPAR and C-reactive protein (CRP).

Results

Our study included 1599 patients in MIMIC-III and 143 patients in the Second Affiliated Hospital of Wenzhou Medical University. The elevated NPAR was independently associated with increased 30-day, 90-day, and one-year all-cause mortality (adjusted HR, 95% CI:1.51 (1.02-2.24); 1.61 (1.14-2.28); 1.53 (1.15-2.03); P trend = 0.0297; 0.0053; 0.0023; respectively), and it was also associated with increase the length of stay in hospital and ICU (β, 95% CI: 2.76 (1.26-4.27); 1.54 (0.62-2.47), respectively, both P trend <0.001). We found that patients with higher NPAR were more likely to receive RRT (OR, 95% CI: 2.50 (1.28-4.89), P trend =0.0023). Moreover, we confirmed that NPAR was statistically positively correlated with CRP (correlation coefficient r = 0.406, P < 0.0001).

Conclusion

Elevated NPAR on admission was independently associated with increased all-cause mortality and length of stay among CICU patients. The results showed that CICU patients with higher NPAR were more likely to receive RRT. Besides, we also provided the evidence that there is a positive correlation between NPAR and inflammatory indicators (ie, CRP).

Prevalence of Noncardiac Multimorbidity in Patients Admitted to Two Cardiac Intensive Care Units and Their Association with Mortality

BACKGROUND

Current cardiac intensive care unit (CICU) practice has seen an increase in patient complexity, including an increase in noncardiac organ failure, critical care therapies, and comorbidities. We sought to describe the changing epidemiology of noncardiac multimorbidity in the CICU population.

METHODS

We analyzed consecutive unique patient admissions to 2 geographically distant tertiary care CICUs (n = 16,390). We assessed for the prevalence of 0, 1, 2, and ≥3 noncardiac comorbidities (diabetes, chronic lung, liver, and kidney disease, cancer, and stroke/transient ischemic attack) and their associations with hospital and postdischarge 1-year mortality using multivariable logistic regression.

RESULTS

The prevalence of 0, 1, 2, and ≥3 noncardiac comorbidities was 37.7%, 31.4%, 19.9%, and 11.0%, respectively. Increasing noncardiac comorbidities were associated with a stepwise increase in mortality, length of stay, noncardiac indications for ICU admission, and increased utilization of critical care therapies. After multivariable adjustment, compared with those without noncardiac comorbidities, there was an increased hospital mortality for patients with 1 (odds ratio [OR] 1.30; 95% confidence interval [CI], 1.10-1.54, P = .002), 2 (OR 1.47; 95% CI, 1.22-1.77, P < .001), and ≥3 (OR 1.79; 95% CI, 1.44-2.22, P < .001) noncardiac comorbidities. Similar trends for each additional noncardiac comorbidity were seen for postdischarge 1-year mortality (P < .001, all).

CONCLUSIONS

In 2 large contemporary CICU populations, we found that noncardiac multimorbidity was highly prevalent and a strong predictor of short- and long-term adverse clinical outcomes. Further study is needed to define the best care pathways for CICU patients with acute cardiac illness complicated by noncardiac multimorbidity.

Incidence and outcomes of acute kidney injury stratified by cardiogenic shock severity

BACKGROUND

Acute kidney injury (AKI) is common among patients with cardiogenic shock (CS) and it is independently associated with mortality. We sought to assess the prevalence, severity, and prognosis of AKI as a function of cardiogenic shock severity in unselected Cardiac Intensive Care Unit (CICU) patients.

METHODS

We retrospectively reviewed admissions to the Mayo Clinic between 2007 to 2015 and stratified patients by the AKI stage (based on modified Kidney Disease: Improving Global Outcomes criteria) and Society for cardiovascular angiography and interventions (SCAI) shock stage. The association with in-hospital mortality was analyzed using multivariable logistic regression.

RESULTS

We included 9,311 unique patients with a mean age of 67 years and 37% females. SCAI shock stages A, B, C, D, and E were present in 47%, 30%, 15%, 7%, and 1% of patients. The incidence of AKI of any severity was 39% in the CICU and 51% during the hospitalization. Hospital mortality occurred in 8% of all patients, and the risk increased as a function of the rising AKI and SCAI shock stage. Worsening AKI stage was associated with increased adjusted hospital mortality (adjusted OR per AKI stage 1.22, 95% CI 1.10-1.36, p < .001). Higher AKI stages were associated with increased adjusted hospital mortality in SCAI stage A/B (p < .001), but not in SCAI stage C, D, or E (all p > .05).

CONCLUSIONS

Higher AKI stages were independently associated with mortality in CICU patients after accounting for shock severity and may add incremental prognostic utility in patients with lower SCAI stages.

Factors Associated with In-Hospital Mortality after Continuous Renal Replacement Therapy for Critically Ill Patients: A Systematic Review and Meta-Analysis

Continuous renal replacement therapy (CRRT) is a broadly-accepted treatment for critically ill patients with acute kidney injury to optimize fluid and electrolyte management. Despite intensive dialysis care, there is a high mortality rate among these patients. There is uncertainty regarding the factors associated with in-hospital mortality among patients requiring CRRT. This review evaluates how various risk factors influence the in-hospital mortality of critically ill patients who require CRRT. Five databases were surveyed to gather relevant publications up to 30 June 2020. We identified 752 works, of which we retrieved 38 in full text. Finally, six cohort studies that evaluated 1190 patients were eligible. The in-hospital mortality rate in these studies ranged from 38.6 to 62.4%. Our meta-analysis results showed that older age, lower body mass index, higher APACHE II and SOFA scores, lower systolic and diastolic blood pressure, decreased serum creatinine level, and increased serum sodium level were significantly associated with increased in-hospital mortality in critically ill patients who received CRRT. These results suggest that there are multiple modifiable factors that influence the risk of in-hospital mortality in critically ill patients undergoing CRRT. Further, healthcare professionals should take more care when CRRT is performed on older adults.

Contemporary Management of Severe Acute Kidney Injury and Refractory Cardiorenal Syndrome: JACC Council Perspectives

Acute kidney injury (AKI) and cardiorenal syndrome (CRS) are increasingly prevalent in hospitalized patients with cardiovascular disease and remain associated with poor short- and long-term outcomes. There are no specific therapies to reduce mortality related to either AKI or CRS, apart from supportive care and volume status management. Acute renal replacement therapies (RRTs), including ultrafiltration, intermittent hemodialysis, and continuous RRT are used to manage complications of medically refractory AKI and CRS and may restore normal electrolyte, acid-base, and fluid balance before renal recovery. Patients who require acute RRT have a significant risk of mortality and long-term dialysis dependence, emphasizing the importance of appropriate patient selection. Despite the growing use of RRT in the cardiac intensive care unit, there are few resources for the cardiovascular specialist that integrate the epidemiology, diagnostic workup, and medical management of AKI and CRS with an overview of indications, multidisciplinary team management, and transition off of RRT.

Epidemiology and outcomes of acute kidney injury in cardiac intensive care unit patients

PURPOSE

To describe the epidemiology and outcomes of acute kidney injury (AKI) among contemporary non-surgical cardiac intensive care unit (CICU) patients.

MATERIALS AND METHODS

We reviewed adult non-surgical CICU patients admitted from 2007 to 2015. The highest AKI stage during hospitalization was defined using modified Kidney Disease: Improving Global Outcomes (KDIGO) criteria, based on changes in serum creatinine. Hospital and 5-year mortality were examined using logistic regression and Cox proportional-hazards models, respectively.

RESULTS

We included 9311 patients with a mean age of 67.5 years, including 37% females. AKI was present in 51%: stage 1 AKI in 34%, stage 2 AKI in 9%, and stage 3 AKI in 8%. Hospital mortality was associated with AKI stage (adjusted OR for each AKI stage 1.17, 95% CI 1.04-1.31, p = 0.007). Five-year mortality was incrementally associated with AKI stage (adjusted HR per AKI stage 1.13, 95% CI 1.08-1.18; p < 0.001), particularly post-discharge mortality among hospital survivors (adjusted HR per AKI stage 1.20, 95% CI 1.15-1.25, p < 0.001). Patients with stage 3 AKI (especially requiring dialysis) had the highest adjusted hospital and five-year mortality.

CONCLUSION

AKI severity is incrementally associated with higher short-term and long-term mortality in CICU patients, especially severe AKI requiring dialysis.