Preoperative right heart hemodynamics predict postoperative acute kidney injury after heart transplantation

Assessing Right Ventricular Function in the Perioperative Setting, Part II: What About Catheters?

Echocardiography is a standard tool for assessing right ventricular (RV) function in the perioperative setting, but in high-risk cases, additional monitoring may be required. Patients with pulmonary hypertension, pre-existing RV failure, or undergoing complex surgeries (eg, pulmonary endarterectomy, LVAD implantation, or transplantation) are particularly vulnerable. Catheter-based techniques, such as pulmonary artery catheterization (PAC), provide continuous, functional data and may be valuable in intensive care or when echocardiography is limited. Despite concerns over complications, PACs can help assess hemodynamics, cardiac output, and RV performance, aiding early detection of RV failure in select high-risk patients.

Machine learning methods to predict transvalvular gradient waveform post-transcatheter aortic valve replacement using preprocedural echocardiogram

OBJECTIVE

Time-varying transvalvular pressure gradient after transcatheter aortic valve replacement indicates the effectiveness of the therapy. The objective was to develop a novel machine learning method enhanced by generative artificial intelligence and smart data selection strategies to predict the post-transcatheter aortic valve replacement gradient waveform using preprocedural Doppler echocardiogram.

METHODS

A total of 110 patients undergoing transcatheter aortic valve replacement (mean age 78.2 ± 9.0 years, 52.5% female) were included for pressure gradient collection. A deep machine learning model was trained and tested to predict postprocedural pressure gradient waveform from preprocedural pressure gradient waveform based on the proposed generative active learning framework.

RESULTS

The trained model demonstrated an average prediction accuracy of 84.85% across the 10 test patients measured from the relative mean absolute error between the predicted gradient waveform and the ground truth. The generative method improved prediction accuracy by 3.11%, whereas the data selection strategy increased it by 16.03% compared with the baseline experimental group using plain machine learning. Additionally, Bland-Altman analysis demonstrated a strong agreement between the proposed method and clinical measurements for both mean and peak pressure gradient predictions.

CONCLUSIONS

A deep, generative, active machine learning model was developed to output the prediction of post-transcatheter aortic valve replacement time-varying pressure gradient from the preprocedural time-varying gradient obtained from Doppler echocardiogram. Such a predictive method may help guide decision-making for the prevention of various post-transcatheter aortic valve replacement complications. Further studies are necessary to investigate the gradient change of other valve types.

Construction and validation of prognostic models for acute kidney disease and mortality in patients at risk of malnutrition: an interpretable machine learning approach

Background

Acute kidney injury (AKI) is a prevalent complication in patients at risk of malnutrition, elevating the risks of acute kidney disease (AKD) and mortality. AKD reflects the adverse events developing after AKI. This study aimed to develop and validate machine learning (ML) models for predicting the occurrence of AKD, AKI and mortality in patients at risk of malnutrition.

Methods

We retrospectively reviewed the medical records of patients at risk of malnutrition. Eight ML algorithms were employed to predict AKD, AKI and mortality. The performance of the best model was evaluated using various metrics and interpreted using the SHapley Additive exPlanation (SHAP) method. An artificial intelligence (AI)-driven web application was also created based on the best model.

Results

A total of 13 395 patients were included in our study. Among them, 1751 (13.07%) developed subacute AKD, 1253 (9.35%) were transient AKI, and 1455 (10.86%) met both AKI and AKD criteria. The incidence rate of mortality was 6.74%. The light gradient boosting machine (LGBM) outperformed other models in predicting AKD, AKI and mortality, with area under curve values of 0.763, 0.801 and 0.881, respectively. The SHAP method revealed that AKI stage, lactate dehydrogenase, albumin, aspirin usage and serum creatinine were the top five predictors of AKD. An online prediction website for AKI, AKD and mortality was developed based on the final models.

Conclusions

The LGBM models provide an effective method for predicting AKD, AKI and mortality at an early stage in patients at risk of malnutrition, enabling prompt interventions. Compared with the AKD model, the models for predicting AKI and mortality perform better. The AI-driven web application can significantly aid in creating personalized preventive measures. Future work will aim to expand the application to larger, more diverse populations, incorporate additional biomarkers and refine ML algorithms to improve predictive accuracy and clinical utility.

A contemporary simple risk score for prediction of severe acute kidney injury after heart transplantation

BACKGROUND

The aim of this study was to develop a simple risk score to estimate severe acute kidney injury (AKI) risk based on a large contemporary heart transplantation (HT) cohort.

METHODS

From 1 January 2015 to 31 December 2021, all consecutive HT recipients in our institute were included and analysed for the occurrence of AKI within the first seven postoperative days. Patients transplanted between 2015 and 2019 comprised the derivation cohort, and those transplanted between 2020 and 2021 formed the validation cohort. The primary endpoint was severe AKI (AKI stages 2-3). The impact of severe AKI on 90 day mortality was also evaluated.

RESULTS

Overall, 430 HT patients were included in the derivation cohort, and 108 were included in the validation cohort. Postoperative AKI occurred in 388 (72%) patients, including 162 (30%) severe AKI. The risk of 90 day mortality significantly increased in patients with severe-AKI. Seven independent predictors of severe AKI were found in the derivation cohort, including recipients' body mass index, history of diabetes, anaemia, preoperative inotropes, estimated glomerular filtration rate, cardiopulmonary bypass duration and intraoperative red blood cell transfusion. The occurrence of severe AKI increased gradually from the lowest to the highest of the four risk score groups in the derivation and validation cohort. The scoring prediction model showed a highly acceptable discriminating power for severe-AKI [C statistic: 0.76, 95% confidence interval (CI): 0.71-0.80 for derivation cohort; C statistic: 0.79, 95% CI: 0.71-0.89 for validation cohort].

CONCLUSIONS

A contemporary simple risk score based on available variables from patients undergoing HT can accurately discriminate the risk of severe AKI.

Impact of Preoperative Right Ventricular Function on Acute Renal Failure Development in Patients With Ventricular Assist Devices

Background Acute kidney injury (AKI) and acute renal failure contribute significantly to the high mortality and morbidity seen in patients with left ventricular assist devices (LVADs). The role of preoperative right ventricular function in the onset of acute renal failure remains an area of active investigation. This study aims to explore the correlation between preoperative right ventricular function and the development of AKI in patients undergoing LVAD implantation. Methods The demographic characteristics, comorbidities, and preoperative and postoperative data of 61 patients who underwent LVAD implantation between April 2012 and December 2021 were carefully documented. Transthoracic echocardiography was used to assess right ventricular function, with tricuspid annular plane systolic excursion (TAPSE) and right ventricular fractional area change (FAC) serving as key evaluation parameters. TAPSE values of ≥17 mm and FAC of ≥35% were considered indicative of normal right ventricular function. Based on these measurements, the study analyzed the association between preoperative right ventricular function and the incidence of postoperative AKI. Results When patients were grouped based on TAPSE values, significant differences emerged in ICU stay duration, hospital stay length, AKI development, and the need for renal replacement therapy post-AKI. Elevated preoperative serum creatinine levels (p = 0.01), older age (p = 0.02), higher body surface area (p = 0.024), and lower TAPSE values (p = 0.02) were identified as risk factors for postoperative AKI. However, no significant correlation was found between preoperative FAC values and AKI incidence in LVAD-implanted patients. Conclusions Preoperative TAPSE appears to be a more reliable predictor of postoperative renal dysfunction than FAC.

Machine learning-based risk prediction of acute kidney disease and hospital mortality in older patients

Introduction

Acute kidney injury (AKI) is a prevalent complication in older people, elevating the risks of acute kidney disease (AKD) and mortality. AKD reflects the adverse events developing after AKI. We aimed to develop and validate machine learning models for predicting the occurrence of AKD, AKI and mortality in older patients.

Methods

We retrospectively reviewed the medical records of older patients (aged 65 years and above). To explore the trajectory of kidney dysfunction, patients were categorized into four groups: no kidney disease, AKI recovery, AKD without AKI, or AKD with AKI. We developed eight machine learning models to predict AKD, AKI, and mortality. The best-performing model was identified based on the area under the receiver operating characteristic curve (AUC) and interpreted using the Shapley additive explanations (SHAP) method.

Results

A total of 22,005 patients were finally included in our study. Among them, 4,434 patients (20.15%) developed AKD, 4,000 (18.18%) occurred AKI, and 866 (3.94%) patients deceased. Light gradient boosting machine (LGBM) outperformed in predicting AKD, AKI, and mortality, and the final lite models with 15 features had AUC values of 0.760, 0.767, and 0.927, respectively. The SHAP method revealed that AKI stage, albumin, lactate dehydrogenase, aspirin and coronary heart disease were the top 5 predictors of AKD. An online prediction website for AKD and mortality was developed based on the final models.

Discussion

The LGBM models provide a valuable tool for early prediction of AKD, AKI, and mortality in older patients, facilitating timely interventions. This study highlights the potential of machine learning in improving older adult care, with the developed online tool offering practical utility for healthcare professionals. Further research should aim at external validation and integration of these models into clinical practice.

Perioperative Risk Factors of Acute Kidney Injury After Heart Transplantation and One-Year Clinical Outcomes: A Retrospective Cohort Study

OBJECTIVES

This study aimed to identify perioperative risk factors of acute kidney injury after heart transplantation and to evaluate 1-year clinical outcomes.

DESIGN

A retrospective single-center cohort study.

SETTING

At a university hospital.

PARTICIPANTS

All patients who underwent heart transplantation from January 2015 to December 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The authors recorded acute kidney injury after heart transplantation. One-year mortality and renal function also were recorded. Risk factors of acute kidney injury were evaluated using a multivariate logistic regression model. Long-term survival was compared between patients developing acute kidney injury and those who did not, using a log-rank test. Among 209 patients included in this study, 134 patients (64% [95% CI (58; 71)]) developed posttransplantation acute kidney injury. Factors independently associated with acute kidney injury were high body mass index (odds ratio [OR]: 1.18 [1.02-1.38] per kg/m2; p = 0.030), prolonged duration of cold ischemic period (OR: 1.11 [1.01-1.24] per 10 minutes; p = 0.039), and high dose of intraoperative dobutamine support (OR: 1.24 [1.06-1.46] per µg/kg/min; p = 0.008). At 1 year, patients who developed postoperative acute kidney injury had higher mortality rates (20% v 8%, p = 0.015). Among 172 survivors at 1 year, 82 survivors (48%) had worsened their renal function compared with preheart transplantation.

CONCLUSIONS

This study highlighted the high incidence of acute kidney injury after heart transplantation and its impact on patient outcomes. Risk factors such as body mass index, prolonged cold ischemic period duration, and level of inotropic support with dobutamine were identified, providing insights for preventive strategies.

Acute Kidney Injury After Heart Transplantation: Risk Factors and Clinical Outcomes

OBJECTIVE

Acute kidney injury (AKI) requiring renal-replacement therapy (RRT) after heart transplantation (OHT) is common and impairs outcomes. This study aimed to identify independent donor and recipient risk factors associated with RRT after OHT.

DESIGN

A retrospective data analysis.

SETTING

Data were collected from clinical routines in a maximum-care university hospital.

PARTICIPANTS

Patients who underwent OHT.

INTERVENTIONS

The authors retrospectively analyzed data from 264 patients who underwent OHT between 2012 and 2021; 189 patients were eligible and included in the final analysis.

MEASUREMENTS AND MAIN RESULTS

The mean age was 48.0 ± 12.3 years, and 71.4% of patients were male. Ninety (47.6%) patients were on long-term mechanical circulatory support (lt-MCS). Posttransplant AKI with RRT occurred in 123 (65.1%) patients. In a multivariate analysis, preoperative body mass index >25 kg/m² (odds ratio [OR] 4.74, p < 0.001), elevated preoperative creatinine levels (OR for each mg/dL increase 3.44, p = 0.004), administration of red blood cell units during transplantation procedure (OR 2.31, p = 0.041) and ischemia time (OR for each hour increase 1.77, p = 0.004) were associated with a higher incidence of RRT. The use of renin-angiotensin-aldosterone system blockers before transplantation was associated with a reduced risk of RRT (OR 0.36, p = 0.013). The risk of mortality was 6.9-fold higher in patients who required RRT (hazard ratio 6.9, 95% CI: 2.1-22.6 p = 0.001). Previous lt-MCS, as well as donor parameters, were not associated with RRT after OHT.

CONCLUSIONS

The implementation of guideline-directed medical therapy, weight reduction, minimizing ischemia time (ie, organ perfusion systems, workflow optimization), and comprehensive patient blood management potentially influences renal function and outcomes after OHT.

Determination of Risk Factors for Acute Kidney Injury In Orthotopic Cardiac Transplantation

BACKGROUND

In this study, we try to determine risk factors for acute kidney injury in orthotopic cardiac transplantation patients.

METHODS

Between February 2003 and December 2022, all cardiac transplantation patients were retrospectively reviewed. Finally, 102 patients enrolled in this study. Demographic data, comorbidities, preoperative cardiac catheterization parameters, preoperative and postoperative blood test results, intraoperative parameters, acute kidney injury developed or not, stage of acute kidney injury, and whether renal replacement therapy was required or not was recorded.

RESULTS

Of the 102 patients, 68 were male. Fifty-four of these patients developed acute kidney injury, and 31 required renal replacement therapy postoperatively. The mean age of developed acute kidney injury group (AKI+) was older than non-developed acute kidney injury group (non-AKI) (P = .01). The average body surface area of the AKI+ was 1.81 ± 0.32, whereas in non-AKI it was 1.57 ± 0.35 (P = .01). More patients were ex-smokers (P = .007) and had a history of hypertension (P= .011) in the AKI+ group. Preoperative serum creatinine was 1.12 ± 0.26 mg/dL in the AKI+ group and 0.82 ± 0.13 mg/dL in the non-AKI group (P = .02). The intraoperative urine output was 491.20 ± 276.48 mL for AKI+ and 676.45 ± 478.84 mL for the non-AKI group (P = .03).

CONCLUSIONS

Acute kidney injury development after cardiac transplantation is common. In our study, high body surface area, older age, ex-smoker, hypertension, low intraoperative urine output, and high preoperative serum creatinine levels were risk factors for acute kidney injury development in cardiac transplantation patients. Mortality and morbidity after cardiac transplantation might be reduced if acute kidney injury development can be lowered.

Severe Acute Kidney Injury Postheart Transplantation: Analysis of Risk Factors

Background

Acute kidney injury (AKI) is a common complication postheart transplantation and is associated with significant morbidity and increased mortality.

Methods

We conducted a single-center, retrospective, observational cohort study of 109 consecutive patients undergoing heart transplantation between September 2019 and September 2021 to determine major risk factors for, and the incidence of, severe postoperative AKI as defined by Kidney Disease Improving Global Outcomes criteria in the first 48-h posttransplantation and the impact that this has on mortality and dialysis dependence.

Results

One hundred nine patients were included in our study, 83 of 109 (78%) patients developed AKI, 42 (39%) developed severe AKI, and 37 (35%) required renal replacement therapy in the first-week posttransplantation. We found preoperative estimated glomerular filtration rate (eGFR), postoperative noradrenaline dose, and the need for postoperative mechanical circulatory support to be independent risk factors for the development of severe AKI. Patients who developed severe AKI had a 19% 12-mo mortality compared with 1% for those without. Of those who survived to hospital discharge, 20% of patients in the severe AKI group required dialysis at time of hospital discharge compared with 3% in those without severe AKI.

Conclusion

Severe AKI is common after heart transplantation. Preoperative kidney function, postoperative vasoplegia with high requirements for vasoactive drugs, and graft dysfunction with the need for mechanical circulatory supports were independently associated with the development of severe AKI in the first-week following heart transplantation. Severe AKI is associated with a significantly increased mortality and dialysis dependence at time of hospital discharge.

The Association of the Pulmonary Artery Pulsatility Index and Right Ventricular Function after Cardiac Surgery

Background

The pulmonary artery pulsatility index (PAPi) has been shown to correlate with right ventricular (RV) failure in patients with cardiac disease. However, the association of PAPi with right ventricular function following cardiac surgery is not yet established.

Methods

PAPi and other hemodynamic variables were obtained postoperatively for 959 adult patients undergoing cardiac surgery. The association of post-bypass right ventricular function and other clinical factors to PAPi was evaluated using linear regression. A propensity-score matched cohort for PAPi ≥ 2.00 was used to assess the association of PAPi with postoperative outcomes.

Results

156 patients (16.3%) had post-bypass right ventricular dysfunction defined by visualization on transesophageal echocardiography. There was no difference in postoperative PAPi based on right ventricular function (2.12 vs. 2.00, p=0.21). In our matched cohort (n = 636), PAPi < 2.00 was associated with increased incidence of acute kidney injury (23.0% vs 13.2%, p < 0.01) and ventilator time (6.0 hours vs 5.6 hours, p=0.04) but not with 30-day mortality or intensive care unit length of stay.

Conclusion

In a general cohort of patients undergoing cardiac surgery, postoperative PAPi was not associated with postcardiopulmonary bypass right ventricular dysfunction. A postoperative PAPi < 2 may be associated with acute kidney injury.

Pulmonary artery pulsatility index predicts mechanical circulatory support following heart transplantation

Background

The incidence of mechanical circulatory support (MCS) for early graft dysfunction (EGD) following heart transplantation varies from 2.3% to 28.2%. Low pulmonary pulsatility index (PAPI) is associated with higher mortality in advanced heart failure and cardiogenic shock. We hypothesized that a lower pulmonary pulsatility index following heart transplantation is associated with MCS use for EGD.

Methods

Two-center study of consecutive heart transplantation from May 2018 to December 2022. Hemodynamic parameters and inotropic/vasoconstrictor data were investigated on admission to the intensive care unit (T0) and at 6 hours later (T6).

Results

Of the 173 patients included in this study, 24 had MCS for EGD. PAPI in the group that required MCS was lower at T0 (1.21 (0.84) vs 1.67 (1.23), p = 0.001) and T6 (0.77 (0.52) vs 1.44 (0.82), p = <0.001). There was no significant difference in recipient characteristics, donor characteristics (donor age and sex matching), and operative factors (warm/cold ischemic time, total ischemic time, cardiopulmonary bypass time) between the 2 groups. On multiple variable regression, PAPI at T6 was associated with delayed MCS independent of total donor organ ischemic time and short-term MCS bridge to transplantation (odds ratio, OR 0.1 (0.036-0.276), p = <0.001). Receiver operating characteristic (ROC) analysis showed an area under the ROC curve of 0.694 for T0 PAPI and 0.832 for T6 PAPI; a cut-off T6 PAPI of 1.22 had sensitivity and specificity of 81% and 65%, respectively.

Conclusions

Lower PAPI at T6 (<1.22) is independently associated with MCS use for severe EGD postheart transplantation.

Heart Transplantation-Postoperative Considerations

Heart transplantation (HT) remains the best treatment of patients with severe heart failure who are deemed to be transplant candidates. The authors discuss postoperative management of the HT recipient by system, emphasizing areas where care might differ from other cardiac surgery patients. Working together, critical care physicians, heart transplant surgeons and cardiologists, advanced practice providers, pharmacists, transplant coordinators, nursing staff, physical therapists, occupational therapists, rehabilitation specialists, nutritionists, health psychologists, social workers, and the patient and their loved ones partner to increase the likelihood of a successful outcome.

Postoperative Pulmonary Artery Pulsatility Index Improves Prediction of Right Ventricular Failure After Left Ventricular Assist Device Implantation

OBJECTIVES

This study evaluated whether the postoperative pulmonary artery pulsatility index (PAPi) is associated with postoperative right ventricular dysfunction after durable left ventricular assist device (LVAD) implantation.

DESIGN

Single-center retrospective observational cohort study.

SETTING

The University of Kansas Medical Center, a tertiary-care academic medical center.

PARTICIPANTS

Sixty-seven adult patients who underwent durable LVAD implantation between 2017 and 2019.

INTERVENTIONS

All patients underwent open cardiac surgery with cardiopulmonary bypass under general anesthesia with pulmonary artery catheter insertion.

MEASUREMENTS AND MAIN RESULTS

Clinical and hemodynamic data were collected before and after surgery. The Michigan right ventricular failure risk score and the European Registry for Patients with Mechanical Circulatory Support score were calculated for each patient. The primary outcome was right ventricular failure, defined as a composite of right ventricular mechanical circulatory support, inhaled pulmonary vasodilator therapy for 48 hours or greater, or inotrope use for 14 days or greater or at discharge. Thirty percent of this cohort (n = 20) met the primary outcome. Preoperative transpulmonary gradient (odds ratio [OR] 1.15, 95% CI 1.02-1.28), cardiac index (OR 0.83, 95% CI 0.71-0.98), and postoperative PAPi (OR 0.85, 95% CI 0.75-0.97) were the only hemodynamic variables associated with the primary outcome. The addition of postoperative PAPi was associated with improvement in the predictive model performance of the Michigan score (area under the receiver operating characteristic curve 0.73 v 0.56, p = 0.03). An optimal cutoff point for postoperative PAPi of 1.56 was found.

CONCLUSIONS

The inclusion of postoperative PAPi offers more robust predictive power for right ventricular failure in patients undergoing durable LVAD implantation, compared with the use of existing risk scores alone.

Obesity Modifies Clinical Outcomes of Right Ventricular Dysfunction

BACKGROUND

Right ventricular (RV) dysfunction is associated with increased mortality across a spectrum of cardiovascular diseases. The role of obesity in RV dysfunction and adverse outcomes is unclear.

METHODS

We examined patients undergoing right heart catheterization between 2005 and 2016 in a hospital-based cohort. Linear regression was used to examine the association of obesity with hemodynamic indices of RV dysfunction (pulmonary artery pulsatility index, right atrial pressure:pulmonary capillary wedge pressure ratio, RV stroke work index). Cox models were used to examine the association of RV function measures with clinical outcomes.

RESULTS

Among 8285 patients (mean age, 63 years; 40% women), higher body mass index was associated with worse indices of RV dysfunction, including lower pulmonary artery pulsatility index (β, -0.23; SE, 0.01; P<0.001), higher right atrium:pulmonary capillary wedge pressure ratio (β, 0.25; SE, 0.01; P<0.001), and lower RV stroke work index (β, -0.05; SE, 0.01; P<0.001). Over median of 7.3 years of follow-up, we observed 3006 mortality and 2004 heart failure hospitalization events. RV dysfunction was associated with a greater risk of mortality (eg, pulmonary artery pulsatility index:hazard ratio, 1.11 per 1-SD increase [95% CI, 1.04-1.18]), with similar associations with risk of heart failure hospitalization. Body mass index modified the effect of RV dysfunction on all-cause mortality (Pinteraction≤0.005 for PAPi and RA:PCWP ratio), such that the effect of RV dysfunction was more pronounced at higher body mass index.

CONCLUSIONS

Patients with obesity had worse hemodynamic measured indices of RV function across a broad hospital-based sample. While RV dysfunction was associated with worse clinical outcomes including mortality and heart failure hospitalization, this association was especially pronounced among individuals with higher body mass index.

Perioperative Management of Heart Transplantation: A Clinical Review

In this clinical review, the authors summarize the perioperative management of heart transplant patients with a focus on hemodynamics, immunosuppressive strategies, hemostasis and hemorrage, and the prevention and treatment of infectious complications.

Pulmonary artery pulsatility index in patients with tricuspid valve regurgitation: a simple non-invasive tool for risk stratification

AIMS

Tricuspid valve regurgitation (TR) is a common valvular disease associated with increased mortality. There is a need for tools to assess the interaction between the pulmonary artery (PA) circulation and the right ventricle in patients with TR and to investigate their association with outcomes. The pulmonary artery pulsatility index (PAPi) has emerged as a haemodynamic risk predictor in left heart disease and pulmonary hypertension (PH). Whether PAPi discriminates risk in unselected patients with greater than or equal to moderate TR is unknown.

METHODS AND RESULTS

In 5079 patients with greater than or equal to moderate TR (regardless of aetiology) and PA systolic and diastolic pressures measured on their first echocardiogram, we compared all-cause mortality at 5 years based on the presence or absence of PH and PAPi levels. A total of 2741 (54%) patients had PH. The median PAPi was 3.0 (IQR 1.9, 4.4). Both the presence of PH and decreasing levels of PAPi were associated with larger right ventricles, worse right ventricular systolic function, higher NT-pro BNP levels, greater degrees of right heart failure, and worse survival. In a subset of patients who had an echo and right heart catheterization within 24 h, the correlation of non-invasive to invasive PA pressures and PAPi levels was very good (r = 0.76).

CONCLUSION

In patients with greater than or equal to moderate TR with and without PH, lower PAPi is associated with right ventricular dysfunction, right heart failure, and worse survival. Incorporating PA pressure and PAPi may help stratify disease severity in patients with greater than or equal to moderate TR regardless of aetiology.

Pre‐operative pulmonary artery pulsatility index does not predict mortality post‐cardiac transplantation

AIMS

The pulmonary artery pulsatility index (PAPi) is a novel haemodynamic marker that has previously been shown to predict right ventricular dysfunction and mortality in patients with pulmonary hypertension and advanced heart failure. Utility of the PAPi in predicting outcomes post-cardiac transplantation is unknown. The aim of this study was to compare the prognostic significance of PAPi against pulmonary vascular resistance (PVR) for the predication of morbidity and all-cause mortality post-transplantation.

METHODS AND RESULTS

All patients who underwent cardiac transplantation over a 6 year period were studied. Pre-operative right heart catheter data was obtained. The PAPi was calculated as follows: (systolic pulmonary artery pressure [sPAP] - diastolic pulmonary artery pressure [dPAP])/right atrial (RA) pressure. One hundred fifty-eight patients with a mean age of 49 ± 14 years were studied (43 with a pre-transplant left ventricular assist device [LVAD]). Three patients were excluded due to missing data. In the non-LVAD group, there was no significant difference in PAPi or PVR, nor was there any association with post-operative outcome (including stratification by natural history sub-type; all P > 0.05). In the LVAD group, there was no association with PAPi and post-operative outcome; however, PVR was predictive of post-operative mortality (mortality: 2.8 ± 1.3 WU vs. alive: 1.7 ± 0.7 WU; P = 0.005).

CONCLUSIONS

The PAPi was not able to discriminate mortality outcomes for patients post-cardiac transplantation. Pulmonary vascular resistance remains a marker of mortality in an LVAD cohort bridged to transplant (central illustration).

Obesity Modifies Clinical Outcomes of Right Ventricular Dysfunction

Introduction

Right ventricular (RV) dysfunction is associated with increased mortality across a spectrum of cardiovascular diseases. The role of obesity in RV dysfunction and adverse outcomes is unclear.

Methods

We examined patients undergoing right heart catheterization between 2005-2016 in a hospital-based cohort. Linear regression was used to examine the association of obesity with hemodynamic indices of RV dysfunction [pulmonary artery pulsatility index (PAPi), right atrial pressure: pulmonary capillary wedge pressure ratio (RAP:PCWP), RV stroke work index (RVSWI)]. Cox models were used to examine the association of RV function measures with clinical outcomes.

Results

Among 8285 patients (mean age 63 years, 40% women), higher BMI was associated with worse indices of RV dysfunction, including lower PAPi (β -0.26, SE 0.01, p <0.001), higher RA:PCWP ratio (β 0.25, SE 0.01, p-value <0.001), and lower RVSWI (β -0.05, SE 0.01, p-value <0.001). Over 7.3 years of follow-up, we observed 3006 mortality and 2004 heart failure (HF) hospitalization events. RV dysfunction was associated with greater risk of mortality (eg PAPi: HR 1.11 per 1-SD increase, 95% CI 1.04-1.18), with similar associations with risk of HF hospitalization. BMI modified the effect of RV dysfunction on outcomes (P-interaction <=0.005 for both), such that the effect of RV dysfunction was more pronounced at higher BMI.

Conclusions

Patients with obesity had worse hemodynamic measured indices of RV function across a broad hospital-based sample. While RV dysfunction was associated with worse clinical outcomes including mortality and HF hospitalization, this association was especially pronounced among individuals with higher BMI.

Impact of diastolic pulmonary gradient and pulmonary artery pulse index on outcomes in heart transplant patients-Results from the Eurotransplant database

Background

Predicting complications associated with pulmonary hypertension (PH) after cardiac transplantation is an important factor when considering cardiac transplantation. The transpulmonary gradient (TPG) is recommended to quantify PH in transplant candidates. Nonetheless, PH remains a common driver of mortality. The diastolic pressure gradient (DPG) and pulmonary vascular resistance (PVR) can differentiate post- from combined pre- and post-capillary PH and may improve estimation of PH-associated risks. We used a large European cohort of transplant candidates to assess whether the pulmonary pulsatility index (PAPi), improves prediction of graft failure and mortality compared to DPG and PVR.

Methods

Out of all patients undergoing heart transplantation between 2009 and 2019 in Eurotransplant member states (n = 10,465), we analyzed the impact of PH (mPAP > 25 mmHg) and right heart catheter hemodynamic data on graft failure and mortality within 1-5 years.

Results

In 1,407 heart transplant patients with PH (79% male, median age 54 years, IQR 39-69 years), the median PVR was 2.5 WU (IQR 1.6 WU) with a median mPAP (pulmonary arterial pressure) of 32 mmHg (IQR 9 mmHg). Patients with low (< 3 mmHg) DPG had a better 5 year survival than those with higher DPG (log rank p = 0.023). TPG, mPAP, PAPi, and PVR did not improve prediction of survival. Low PAPi (OR = 2.24, p < 0.001) and high PVR (OR = 2.12, p = 0.005) were associated with graft failure.

Conclusion

PAPI and PVR are associated with graft failure in patients with PH undergoing cardiac transplantation. DPG is associated with survival in this cohort.

Comparing the associations of central venous pressure and pulmonary artery pulsatility index with postoperative renal injury

Objective

Cardiac surgery-associated acute kidney injury (CS-AKI) is associated with significant morbidity and mortality. We investigated the association of postoperative central venous pressure (CVP) and pulmonary artery pulsatility index (PAPi) with the development of CS-AKI.

Methods

This was a single-center, retrospective cohort study of patients undergoing cardiac surgery. CVP and PAPi were acquired hourly postoperatively and averaged for up to 48 h. PAPi was calculated as [(Pulmonary Artery Systolic Pressure–Pulmonary Artery Diastolic Pressure) / CVP]. The primary aim was CS-AKI. Secondary aims were need for renal replacement therapy (RRT), hospital and 30-day mortality, total ventilator and intensive care unit hours, and hospital length of stay. Logistic regression was used to calculate odds of development of renal injury and need for RRT.

Results

One thousand two hundred eighty-eight patients were included. The average postoperative CVP was 10.3 mmHg and average postoperative PAPi was 2.01. Patients who developed CS-AKI (n = 384) had lower PAPi (1.79 vs. 2.11, p < 0.01) and higher CVP (11.5 vs. 9.7 mmHg, p < 0.01) than those who did not. Lower PAPi and higher CVP were also associated with each secondary aim. A standardized unit decrease in PAPi was associated with increased odds of CS-AKI (OR 1.39, p < 0.01) while each unit increase in CVP was associated with both increased odds of CS-AKI (OR 1.56, p < 0.01) and postoperative RRT (OR 1.49, p = 0.02).

Conclusions

Both lower PAPi and higher CVP values postoperatively were associated with the development of CS-AKI but only higher CVP was associated with postoperative RRT use. When differences in values are standardized, CVP may be more associated with development of CS-AKI when compared to PAPi.

Incremental value of preoperative right ventricular function in predicting moderate to severe acute kidney injury after heart transplantation

Background

Acute kidney injury (AKI) commonly occurs after heart transplantation (HTx), but its association with preoperative right ventricular (RV) function remains unknown. Consequently, we aimed to determine the predictive value of preoperative RV function for moderate to severe AKI after HTx.

Materials and methods

From 1 January 2016 to 31 December 2019, all the consecutive HTx recipients in our center were enrolled and analyzed for the occurrence of postoperative AKI staged by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Conventional RV function parameters, including RV fractional area change (RVFAC) and tricuspid annular plane systolic excursion (TAPSE), were obtained. The primary endpoint was moderate to severe AKI (the KDIGO stage 2 or 3). The secondary endpoints included the impact of AKI on intensive care unit (ICU) mortality, in-hospital mortality, and 1-year mortality.

Results

A total of 273 HTx recipients were included in the study. Postoperative AKI occurred in 209 (77%) patients, including 122 (45%) patients in stage 1 AKI, 49 (18%) patients in stage 2 AKI, and 38 (14%) patients in stage 3 AKI. Patients with higher AKI stage had lower baseline estimated glomerular filtration rate (eGFR), more frequent diabetes, higher right atrial pressure (RAP), longer cardiopulmonary bypass (CPB) duration, more perioperative red blood cell (RBC) transfusions, and worse preoperative RV function. A multivariate logistic regression model incorporating previous diabetes mellitus [odds ratio (OR): 2.21; 95% CI: 1.06–4.61; P = 0.035], baseline eGFR (OR: 0.99; 95% CI: 0.97–0.10; P = 0.037), RAP (OR: 1.05; 95% CI: 1.00–1.10; P = 0.041), perioperative RBC (OR: 1.18; 95% CI: 1.08–1.28; P < 0.001), and TAPSE (OR: 0.84; 95% CI: 0.79–0.91; P < 0.001) was established to diagnose moderate to severe AKI more accurately [the area under the curve (AUC) = 79.8%; Akaike information criterion: 274].

Conclusion

Preoperative RV function parameters provide additional predicting value over clinical and hemodynamic parameters, which are imperative for risk stratification in patients with HTx at higher risk of AKI.

Machine learning to predict post-operative acute kidney injury stage 3 after heart transplantation

BACKGROUND

Acute kidney injury (AKI) stage 3, one of the most severe complications in patients with heart transplantation (HT), is associated with substantial morbidity and mortality. We aimed to develop a machine learning (ML) model to predict post-transplant AKI stage 3 based on preoperative and perioperative features.

METHODS

Data from 107 consecutive HT recipients in the provincial center between 2018 and 2020 were included for analysis. Logistic regression with L2 regularization was used for the ML model building. The predictive performance of the ML model was assessed using the area under the curve (AUC) in tenfold stratified cross-validation and was compared with that of the Cleveland-clinical model.

RESULTS

Post-transplant AKI occurred in 76 (71.0%) patients including 15 (14.0%) stage 1, 18 (16.8%) stage 2, and 43 (40.2%) stage 3 cases. The top six features selected for the ML model to predicate AKI stage 3 were serum cystatin C, estimated glomerular filtration rate (eGFR), right atrial long-axis dimension, left atrial anteroposterior dimension, serum creatinine (SCr) and FVII. The predictive performance of the ML model (AUC: 0.821; 95% confidence interval [CI]: 0.740-0.901) was significantly higher compared with that of the Cleveland-clinical model (AUC: 0.654; 95% [CI]: 0.545-0.763, p < 0.05).

CONCLUSIONS

The ML model, which achieved an effective predictive performance for post-transplant AKI stage 3, may be helpful for timely intervention to improve the patient's prognosis.

Prognosis of Advanced Heart Failure Patients according to Their Hemodynamic Profile Based on the Modified Forrester Classification

Introduction: Heart transplantation (HT) remains the gold-standard treatment but is conditioned by organ shortage. This study aimed to evaluate the value of Forrester classification and determine which congestion criteria had the best prognostic value to predict cardiorenal events on heart transplant waiting list. Methods and results: One hundred consecutive patients (54 years old, 72% men) with available right heart catheterization (RHC) listed in our center for HT between 2014 and 2019 were included. Cardiac catheterization measurements were obtained at the time of HT listing evaluation. Patients were classified according to perfusion and congestion status in four groups: “warm and dry”, “warm and wet”, “cold and dry”, and “cold and wet”. pWet was used to classify patients with pulmonary congestion and sWet for systemic congestion. The primary endpoint was the rate of a composite criteria of cardiogenic shock, acute kidney injury, and acute heart failure. Secondary endpoint was the incidence of waitlist death, emergency HT, or left ventricular assist device (LVAD) implantation at 12 months evaluated by Kaplan–Meier curves and log-rank test. Only Forrester classification according to systemic congestion was associated with the primary composite endpoint (p = 0.011), while patients’ profile according to pulmonary congestion was not (p = 0.331). Similarly, only the Forrester classification according to systemic congestion predicted waitlist death, emergency HT, or LVAD implantation at 12 months, with p = 0.010 and p = 0.189 for systemic and pulmonary congestion, respectively. Moreover, systemic congestion was the main driver of cardiorenal events on waitlist. Conclusions: Forrester classification according to systemic congestion is associated with cardiorenal outcomes in patients listed for heart transplant and the risk of waitlist death, emergency HT, or LVAD implantation at 12 months.

A Novel Hemodynamic Index of Post-operative Right Heart Dysfunction Predicts Mortality in Cardiac Surgical Patients

INTRODUCTION

This study aimed to investigate whether mortality following cardiac surgery was associated with the pulmonary artery pulsatility index (PAPi): pulmonary artery pulse pressure divided by central venous pressure (CVP), and a novel index: mean pulmonary artery pressure (mPAP) minus CVP.

METHODS

This retrospective analysis investigated all cardiac surgery patients in the Society of Thoracic Surgeons registry at a single academic medical center from January 2017 through March 2020 (n = 1510). The primary and secondary outcomes were mortality at 1 year and serum creatinine increase during index surgical admission, respectively. CVP, mPAP, PAPi, mPAP-CVP gradient, mean arterial pressure (MAP), and cardiac index (CI) were sampled continually from invasive hemodynamic monitors post-operatively. Associations with mortality were tested with univariate and multivariate analyses. The relationship with serum creatinine was investigated with Pearson's correlation at alpha = .05.

RESULTS

One-year mortality was observed in 44/1200 patients (3.7%). On univariate analysis, mortality was associated with minimums for mPAP, MAP, and CI and maximums for CVP, mPAP, PAPi, mPAP-CVP gradient, and CI (all P < .10). Model selection revealed that the only independently predictive parameters were minimum MAP (AOR = .880 [.819-.944]), maximum mPAP-CVP gradient (AOR = 1.082 [1.031-1.133]), and maximum CI (AOR = 1.421 [.928-2.068]), with model c-statistic = .770. A maximum mPAP-CVP gradient >20.5 predicted mortality with 54.5% sensitivity and 79.30% specificity, maintaining significance on survival analysis (P < .001). Peak increase in serum creatinine from baseline demonstrated a weak association with all parameters (max |r| = .33).

CONCLUSIONS

Mortality was not predicted by the post-operative PAPi; rather, it was independently predicted by the mPAP-CVP gradient, MAP, and CI.

Emerging early diagnostic methods for acute kidney injury

Many factors such as trauma and COVID-19 cause acute kidney injury (AKI). Late AKI have a very high incidence and mortality rate. Early diagnosis of AKI provides a critical therapeutic time window for AKI treatment to prevent progression to chronic renal failure. However, the current clinical detection based on creatinine and urine output isn't effective in diagnosing early AKI. In recent years, the early diagnosis of AKI has made great progress with the advancement of information technology, nanotechnology, and biomedicine. These emerging methods are mainly divided into two aspects: First, predicting AKI through models construct by machine learning; Second, early diagnosis of AKI through detection of newly-discovered early biomarkers. Currently, these methods have shown great potential and become an attractive tool for the early diagnosis of AKI. Therefore, it is very important to discuss and summarize these methods for the early diagnosis of AKI. In this review, we first systematically summarize the application of machine learning in AKI prediction algorithms and specific scenarios. In addition, we introduce the key role of early biomarkers in the progress of AKI, and then comprehensively summarize the application of emerging detection technologies for early AKI. Finally, we discuss current challenges and prospects of machine learning and biomarker detection. The review is expected to provide new insights for early diagnosis of AKI, and provided important inspiration for the design of early diagnosis of other major diseases.

Association of Pulmonary Artery Pulsatility Index With Adverse Cardiovascular Events Across a Hospital-Based Sample

BACKGROUND

The pulmonary artery pulsatility index (PAPi), calculated from the ratio of the pulmonary artery pulse pressure to right atrial pressure, is a predictor of right ventricular failure after inferior myocardial infarction and left ventricular assist device implantation. Whether PAPi is associated with adverse outcomes across a heterogeneous population is unknown.

METHODS

We examined consecutive patients undergoing right heart catheterization between 2005 and 2016 in a hospital-based cohort. Multivariable Cox models were utilized to examine the association between PAPi and all-cause mortality, major adverse cardiac events, and heart failure hospitalizations.

RESULTS

We studied 8285 individuals (mean age 63 years, 39% women) with median PAPi across quartiles 1.7, 2.8, 4.2, and 8.7, who were followed over a mean follow-up of 6.7±3.3 years. Patients in the lowest PAPi quartile had a 60% greater risk of death compared with the highest quartile (multivariable-adjusted hazard ratio, 1.60 [95% CI, 1.36-1.88], P<0.001) and a higher risk of major adverse cardiac events and heart failure hospitalizations (hazard ratio, 1.80 [95% CI, 1.56-2.07], P<0.001 and hazard ratio, 2.08 [95% CI, 1.76-2.47], P<0.001, respectively). Of note, patients in quartiles 2 and 3 also had increased risk of cardiovascular events compared with quartile 4 (multivariable P<0.05 for all).

CONCLUSIONS

Compared with the highest PAPi quartile, patients in PAPi quartiles 1 to 3 had a greater risk of all-cause mortality, major adverse cardiac events, and heart failure hospitalizations, with greatest risk observed in the lowest quartile. A low PAPi, even at values higher than previously reported, may serve an important role in identifying high-risk individuals across a broad spectrum of cardiovascular disease.

Prognostic value of pulmonary artery pulsatility index in chronic heart failure patients with reduced ejection fraction

BACKGROUND

The co-existence of right ventricular dysfunction (RVD) in heart failure patient with reduced ejection fraction (HFrEF) is an independent maker of poor prognosis. A novel right ventricular hemodynamic composite measure is the pulmonary artery pulsatility index (PAPi), which is the pulmonary artery pressure gradient ratio. It is a strong predictor of RVD in patients with acute inferior myocardial infarction and patients undergoing left ventricular assist device (LVAD) implantation. However, little is known about its prognostic value in patients with HFrEF.

METHODS

Between September 2010 and July 2013, 172 patients with HFrEF admitted to the tertiary hospital were included in this analysis. We carried out a cardiac catheterisation for each patient, at baseline. Subsequently, we evaluated both PAPi and the other hemodynamic parameters with longitudinal follow-up of adverse outcomes such as cardiac mortality, LVAD, and heart transplantation (HTx).

RESULTS

During a median follow-up period of 52 months we observed 50 cardiac deaths, 12 LVAD implantations and 10 HTx. A threshold for PAPi value of 2.82 was ascertained (Area: 0.76, p < 0.001, CI: 0.67-0.85, sensitivity 67%, specificity 69%). After dividing the study population into two groups, PAPi ≤2.82 and PAPi >2.82, no significant difference was demonstrated with respect to the aetiology of heart failure (ischaemic HFrEF p = 0.29 and non-ischaemic HFrEF p = 0.29). In Cox regression survival analysis, PAPi was an independent predictor of cardiac death (hazard ratio 0.73 [95% confidence interval 0.53-0.99], p = 0.045).

CONCLUSION

In patients with HFrEF, a low PAPi value (<2.82) was associated with increased cardiac mortality risk.

Haemodynamic parameters associated with renal function prior to and following heart transplantation

AIMS

Abnormal renal function is a common feature in patients on heart transplant waiting lists. This study aimed to identify the haemodynamic parameters associated with decreased estimated glomerular filtration rate (eGFR) in patients listed for heart transplantation (HT) and renal function improvement following HT.

METHODS AND RESULTS

A total of 176 adults (52 years old, 81% men) with available right heart catheterization (RHC) listed in our centre for HT between 2014 and 2019 were studied. Cardiac catheterization measurements were obtained at time of HT listing evaluation. Changes in renal function were assessed between RHC and 6 months after HT. Median eGFR was 63 mL/min/1.73 m2 at time of RHC. Central venous pressure > 10 mmHg was associated with a two-fold increase in the likelihood of eGFR < 60 mL/min/1.73 m2 at time of RHC (adjusted odd ratio, 2.2; 95% confidence interval, 1.1-4.7; P = 0.04). In the 134 patients (76%) who underwent HT during follow-up, eGFR decreased by 7.9 ± 29.7 mL/min/1.73 m2 from RHC to 6 months after HT. In these patients, low cardiac index (<2.1 L/min/m2 ) at initial RHC was associated with a (adjusted) 6 month post-HT eGFR improvement of 12.2 mL/min/1.73 m2 (P = 0.018). Patients with eGFR < 60 mL/min/1.73 m2 and low cardiac index at time of RHC exhibited the greatest eGFR improvement (delta eGFR = 18.3 mL/min/1.73 m2 ) while patients with eGFR ≥ 60 mL/min/1.73 m2 and normal cardiac index had a marked decrease in eGFR (delta eGFR = -27.7 mL/min/1.73 m2 , P < 0.001).

CONCLUSIONS

Central venous pressure is the main haemodynamic parameter associated with eGFR < 60 mL/min/1.73 m2 in patients listed for HT. Low cardiac index prior to HT is associated with post-transplant renal function recovery.

Pretransplant Right Ventricular Dysfunction Is Associated With Increased Mortality After Heart Transplantation: A Hard Inheritance to Overcome

BACKGROUND

Right ventricular dysfunction (RVD) is a major issue in patients with advanced heart failure because it precludes the implantation of left ventricular assist device, usually leaving heart transplantation (HTx) as the only available treatment option. The pulmonary artery pulsatility index (PAPi) is a hemodynamic parameter integrating information of right ventricular function and of pulmonary circulation. Our aim is to evaluate the association of preoperative RVD, hemodynamically defined as a low PAPi, with post-HTx survival.

METHODS AND RESULTS

Consecutive adult HTx recipient at 2 Italian transplant centers between 2000 and 2018 with available data on pre-HTx right heart catheterization were included retrospectively. RVD was defined as a value of PAPi lower than the 25th percentile of the study population. The association of RVD with the 1-year post-HTx mortality and other secondary end points were evaluated. Multivariate logistic regression was used to adjust for clinical and hemodynamic variables. Analyses stratified by pulmonary vascular resistance (PVR) status (≥3 Woods units vs <3 Woods units) were also performed. Among 657 HTx recipients (female 31.1%, age 53 ± 11 years), patients with pre-HTx RVD (PAPi of <1.68) had significantly lower 1-year survival rates (77.8% vs 87.1%, P = .005), also after adjusting for estimated glomerular filtration rate, total bilirubin, PVR, serum sodium, inotropes, and mechanical circulatory support at HTx (hazard ratio 2.0, 95% confidence interval, 1.3-3.1). RVD was also associated with post-HTx renal replacement therapy (hazard ratio 2.0, 95% confidence interval 1.05-3.30) and primary graft dysfunction (hazard ratio 1.7, , 95% confidence interval 1.02-3.30). When stratifying patients by estimated PVR status, RVD was associated with worse 1-year survival among patients with normal PVR (76.9% vs 88.3%, P = .003), but not in those with increased PVR (78.6% vs 83.2%, P = .49).

CONCLUSIONS

Preoperative RVD, evaluated through PAPi, is associated with mortality and morbidity after HTx, providing incremental prognostic value over traditional clinical and hemodynamic parameters.

Acute Kidney Injury in Cardiogenic Shock: An Updated Narrative Review

Acute myocardial infarction with cardiogenic shock (AMI-CS) is associated with high mortality and morbidity despite advancements in cardiovascular care. AMI-CS is associated with multiorgan failure of non-cardiac organ systems. Acute kidney injury (AKI) is frequently seen in patients with AMI-CS and is associated with worse mortality and outcomes compared to those without. The pathogenesis of AMI-CS associated with AKI may involve more factors than previously understood. Early use of renal replacement therapies, management of comorbid conditions and judicious fluid administration may help improve outcomes. In this review, we seek to address the etiology, pathophysiology, management, and outcomes of AKI complicating AMI-CS.

Outcomes of Orthotopic Heart Transplantation in the Setting of Acute Kidney Injury and Renal Replacement Therapy

OBJECTIVE

Heart transplantation in the setting of renal insufficiency is controversial. The objective of this study was to perform a descriptive analysis of patients who underwent orthotopic heart transplantation and renal replacement therapy (RRT) due to acute kidney injury (AKI).

DESIGN

An observational cohort study with retrospective data collection.

SETTING

A tertiary care hospital.

PARTICIPANTS

Fifty-one patients underwent orthotopic heart transplantation with cardiogenic shock under inotrope dependence, with nine patients having preoperative RRT and 42 patients not having preoperative RRT.

INTERVENTIONS

There were no interventions.

MEASUREMENTS AND MAIN RESULTS

Hospital mortality occurred in eight (15.6%) patients. Although there were no significant differences between the study groups (preoperative RRT 33.3% v controls 11.9%, p = 0.1), this study was underpowered to detect differences in mortality. Dialysis also was required in 52.4% of patients who were not on preoperative RRT. All survivors had full recovery of kidney function with similar timing after transplant (18.5 days v 15 days, p = 0.75). Actuarial survival was 82.4%, 76.5%, and 66.5% at six months, one year, and five years, respectively. A cold ischemic time greater than 180 minutes (hazard ratio [HR] 4.37 95% confidence interval [CI] 1.51-12.6; p = 0.006) and pretransplant RRT (HR = 7.19 95% CI 1.13-45.7; p = 0.04) were independent predictors of long-term mortality.

CONCLUSIONS

In a health system with limited funding and availability of mechanical circulatory support, heart transplantation in the setting of AKI, RRT, and low Interagency Registry for Mechanically Assisted Circulatory Support profile was associated with important hospital mortality. Among hospital survivors, however, all patients had full renal recovery and by 25 months there was no difference in mortality between those who required preoperative RRT and those who did not.

Early Goal-Directed Renal Replacement Therapy in Acute Decompensated Heart Failure Patients with Cardiorenal Syndrome

INTRODUCTION

The aim of this study was to clarify the efficacy of early goal-directed renal replacement therapy (GDRRT) for treatment of cardiorenal syndrome (CRS) patients after acute decompensated heart failure (ADHF).

METHODS

In the retrospective, observational study, we enrolled 54 patients in the early GDRRT group and 63 patients in the late GDRRT group. Baseline characteristics, clinical data at initiation renal replacement therapy time, and the clinical outcome were collected and several parameters were compared and analyzed between 2 groups.

RESULTS

The urine volume at GDRRT initiation time in the early group was higher than that in the late GDRRT group (1,060.3 ± 332.1 vs. 300.5 ± 148.3 mL, p < 0.001). Hemodynamic parameters such as mean artery pressure were higher (70.06 ± 32.99 vs. 54.34 ± 40.88 mm Hg, p = 0.012), the heart rate was slower (80.17 ± 15.26 vs. 99.21 ± 25.45 bpm, p = 0.002), and the diameter of inferior vena cava was narrower (22.00 ± 1.91 vs. 25.77 ± 5.5 mm, p = 0.04) in early GDRRT. Primary end point was inhospital all-cause mortality and cardiovascular mortality, which was obviously lower in the early GDRRT group (respectively 24.1 vs. 60.3%, p = 0.002 and 20.3 vs. 50.8%, p = 0.005). The second end point of kidney recovery in the early GDRRT group was much better than that in the latter GDRRT group (p = 0.018). Moreover, urine volume after GDRRT of the early group was more significant than that of the late group (1,432 ± 172 vs. 702 ± 183 mL, p = 0.005).

CONCLUSION

This study clarified the effectiveness of the early GDRRT strategy in ADHF patients suffered from CRS, which reduced inhospital mortality and improved the urine output and clinical kidney recovery outcome.

Cardio-Pulmonary-Renal Consequences of Severe COVID-19

Severe acute respiratory syndrome coronavirus 2 has rapidly spread worldwide and resulted in the coronavirus disease 2019 (COVID-19) pandemic. The disease raised an unprecedented demand for intensive care support due to severe pulmonary dysfunction and multiorgan failure. Although the pulmonary system is the potential target of the COVID-19, recent reports have demonstrated that COVID-19 profoundly influences the cardiovascular system and the kidneys. Research studies on cadavers have shown that direct heart and kidney injury can be frequently seen in patients deceased due to COVID-19 infection. On the other hand, functional or structural dysfunction of the heart may deteriorate the renal function and vice versa. This concept is already known as the cardiorenal syndrome and may play a role in COVID-19. Proactive monitoring of micro- and macrohemodynamics could allow prompt correction of circulatory dysfunction and can be of pivotal importance in the prevention of acute kidney injury. Moreover, type and amount of fluid therapy and vasoactive drug support could help manage these patients either with or without mechanical ventilator support. This brief review outlines the current evidence regarding the COVID-19-related renal and cardiorenal complications and discusses potential hemodynamic management strategies.

Cardiac Ultrasound for the Nephrologist: Know Thy Heart to Know Thy Kidneys

Kidney disease patients have a high prevalence of cardiovascular morbidity and mortality. It can be challenging to adequately assess their cardiovascular status based on physical examination alone. Cardiac ultrasound has proven to be a powerful tool to accomplish this objective and is increasingly being adopted by noncardiologists to augment their skills and expedite clinical decision-making. With the advent of inexpensive and portable ultrasound equipment, simplified protocols, and focused training, it is becoming easier to master basic cardiac ultrasound techniques. After a short course of training in focused cardiac ultrasound, nephrologists can quickly and reliably assess ventricular size and function, detect clinically relevant pericardial effusion and volume status in their patients. Additional training in Doppler ultrasound can extend their capability to measure cardiac output, right ventricular systolic pressure, and diastolic dysfunction. This information can be instrumental in effectively managing patients in inpatient, office, and dialysis unit settings. The purpose of this review is to highlight the importance and feasibility of incorporating cardiac ultrasound in nephrology practice, discuss the principles of basic and Doppler ultrasound modalities and their clinical utility from a nephrologist's perspective.

Care for the organ transplant recipient on the intensive care unit

All transplant recipients receive tacrolimus, mycophenolate and glucocorticoids and these drugs have many side-effects and drug-drug interactions. Common complications include surgical complications, infections, rejection and acute kidney injury. Infections as CMV and PJP can be prevented with prophylactic treatment. Given the complexity of organ transplant recipients a multi-disciplinary team of intensivists, surgeons, pharmacists and transplant specialists is essential. After heart transplantation a temporary pacemaker is required until the conduction system recovers. Stiffening of the heart and increased cardiac markers indicate rejection. An endomyocardial biopsy is performed via the right jugular vein, necessitating its preservation. For lung transplant patients, early intervention for aspiration is warranted to prevent chronic rejection. Risk of any infection is high, requiring active surveillance and intensive treatment, mainly of fungal infections. The liver is immunotolerant requiring lower immunosuppression. Transplantation surgery is often accompanied by massive blood loss and coagulopathy. Other complications include portal vein or hepatic artery thrombosis and biliary leakage or stenosis. Kidney transplant recipients have a high risk of cardiovascular disease and posttransplant anemia should be treated liberally. After postmortal transplantation, delayed graft function is common and dialysis is continued. Ureteral anastomosis complications can be diagnosed with ultrasound.

Acute Kidney Injury After Heart Transplant: The Importance of Pulmonary Hypertension

OBJECTIVE

To determine whether relative pulmonary hypertension (PH), defined as the ratio of mean arterial pressure to mean pulmonary artery pressure, is associated with severe acute kidney injury (AKI) after heart transplant (HT).

DESIGN

An institutional review board-approved retrospective observational study.

SETTING

Tertiary care university hospital.

PARTICIPANTS

A total of 184 consecutive adult patients who underwent HT between January 2009 and December 2017 were included, and were followed up through December 2019. Using the Kidney Disease: Improving Global Outcomes classification, recipients were categorized into two groups: patients who developed stage 3 AKI (severe AKI) and those with minor or without AKI (nonsevere AKI) within seven days after transplant.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the included patients, 83.2% developed AKI, in whom 40.8%, 19.6%, and 22.8% were stage 1, 2, and 3, respectively. With use of the multivariate logistic regression analysis, independent risk factors for stage 3 AKI post-HT included preoperative relative PH (odds ratio [OR]: 1.62, 95% confidence interval [95% CI]: 1.05-2.49, p = 0.028), central venous-to-pulmonary capillary wedge pressure ratio ≥0.86 (OR: 3.59, 95% CI: 1.13-11.43, p = 0.030), and postoperative right ventricular dysfunction (OR: 3.63, 95% CI: 1.50-8.75, p = 0.004). Conversely, preoperative estimated glomerular filtration rate (OR: 0.99, 95% CI: 0.97-1.00, p = 0.143) was not related to the development of stage 3 AKI post-HT.

CONCLUSIONS

Preoperative relative PH, central venous-to-pulmonary capillary wedge pressure ratio, and postoperative right ventricular failure by echocardiographic assessment were associated with severe AKI post-HT.

Congestive nephropathy: a neglected entity? Proposal for diagnostic criteria and future perspectives

Venous congestion has emerged as an important cause of renal dysfunction in patients with cardiorenal syndrome. However, only limited progress has been made in differentiating this haemodynamic phenotype of renal dysfunction, because of a significant overlap with pre-existing renal impairment due to long-term hypertension, diabetes, and renovascular disease. We propose congestive nephropathy (CN) as this neglected clinical entity. CN is a potentially reversible subtype of renal dysfunction associated with declining renal venous outflow and progressively increasing renal interstitial pressure. Venous congestion may lead to a vicious cycle of hormonal activation, increased intra-abdominal pressure, excessive renal tubular sodium reabsorption, and volume overload, leading to further right ventricular (RV) stress. Ultimately, renal replacement therapy may be required to relieve diuretic-resistant congestion. Effective decongestion could preserve or improve renal function. Congestive acute kidney injury may not be associated with cellular damage, and complete renal function restoration may be a confirmatory diagnostic criterion. In contrast, a persistently low renal perfusion pressure might induce renal dysfunction and histopathological lesions with time. Thus, urinary markers may differ. CN is mostly seen in biventricular heart failure but may also occur secondary to pulmonary arterial hypertension and elevated intra-abdominal pressure. An increase in central venous pressure to >6 mmHg is associated with a steep decrease in glomerular filtration rate. However, the central venous pressure range that can provide an optimal balance of RV and renal function remains to be determined. We propose criteria to identify cardiorenal syndrome subgroups likely to benefit from decongestive or pulmonary hypertension-specific therapies and suggest areas for future research.

Incidence, risk factors and clinical outcomes of acute kidney injury after heart transplantation: a retrospective single center study

Objectives

This study aimed to identify the incidence rate of Acute kidney injury (AKI) in our center and predict in-hospital mortality and long-term survival after heart transplantation (HTx).

Methods

This single-center, retrospective study from October 2009 and March 2020 analyzed the pre-, intra-, and postoperative characteristics of 95 patients who underwent HTx. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Risk factors were analyzed by multivariable logistic regression models. The log-rank test was used to compare long-term survival.

Results

Thirty-three (34.7%) patients developed AKI. The mortality in hospital in HTx patients with and without AKI were 21.21 and 6.45%, respectively (P < 0.05). Recipients in AKI who required renal replacement therapy (RRT) had a hospital mortality rate of 43.75% compared to 6.45% in those without AKI or RRT (P < 0.0001). A long cardiopulmonary bypass (CPB) time (OR:11.393, 95% CI: 2.183 to 59.465, P = 0.0039) was positively related to the occurrence of AKI. A high intraoperative urine volume (OR: 0.031, 95% CI: 0.005 to 0.212, P = 0.0004) was negatively correlated with AKI. AKI requiring RRT (OR, 11.348; 95% CI, 2.418–53.267, P = 0.002) was a risk factor for mortality in hospital. Overall survival in patients without AKI at 1 and 3 years was not different from that in patients with AKI (P = 0.096).

Conclusions

AKI is common after HTx. AKI requiring RRT could contribute powerful prognostic information to predict mortality in hospital. A long CPB time and low intraoperative urine volume are associated with the occurrence of AKI.

The impact of severe acute kidney injury requiring renal replacement therapy on survival and renal function of heart transplant recipients - a UK cohort study

Severe acute kidney injury (AKI), defined as requiring renal replacement therapy (RRT), is associated with higher mortality postheart transplantation, but its long-term renal consequences are not known. Anonymized data of 3365 patients, who underwent heart transplantation between 1995 and 2017, were retrieved from the UK Transplant Registry. Multivariable binary logistic regression was performed to identify risk factors for severe AKI requiring RRT, Kaplan-Meier analysis to compare survival and renal function deterioration of the RRT and non-RRT groups, and multivariable Cox regression model to identify predicting factors of mortality and end-stage renal disease (ESRD). 26.0% of heart recipients received RRT post-transplant. The RRT group has lower survival rates at all time points, especially in the immediate post-transplant period. However, conditional on 3 months survival, older age, diabetes and coronary heart disease, but not post-transplant RRT, were the risk factors for long-term survival. The predicting factors for ESRD were insulin-dependent diabetes, renal function at transplantation, eGFR decline in the first 3 months post-transplant, post-transplant severe AKI and transplantation era. Severe AKI requiring RRT post-transplant is associated with worse short-term survival, but has no impact on long-term mortality. It also accelerates recipients' renal function deterioration in the long term.

Pulmonary artery pulsatility index: physiological basis and clinical application

Pulmonary artery pulsatility index (PAPi) is a haemodynamic parameter that is derived from right atrial and pulmonary artery pulse pressures. A number of reports have described the prognostic value of PAPi in patients with advanced heart failure and cardiogenic shock. However, the derivation and physiological interpretation of this parameter have received little attention. This review will examine the physiological interpretation and clinical data for PAPi.

Acute Kidney Injury in Patients Undergoing Cardiac Transplantation: A Meta-Analysis

Background: Acute kidney injury (AKI) is a common complication following solid-organ transplantation. However, the epidemiology of AKI and mortality risk of AKI among patients undergoing cardiac transplantation is not uniformly described. We conducted this study to assess the incidence of AKI and mortality risk of AKI in adult patients after cardiac transplantation. Methods: A systematic review of EMBASE, MEDLINE, and Cochrane Databases was performed until June 2019 to identify studies evaluating the incidence of AKI (by standard AKI definitions), AKI requiring renal replacement therapy (RRT), and mortality risk of AKI in patients undergoing cardiac transplantation. Pooled AKI incidence and mortality risk from the included studies were consolidated by random-effects model. The protocol for this study is registered with PROSPERO (no. CRD42019134577). Results: 27 cohort studies with 137,201 patients undergoing cardiac transplantation were identified. Pooled estimated incidence of AKI and AKI requiring RRT was 47.1% (95% CI: 37.6-56.7%) and 11.8% (95% CI: 7.2-18.8%), respectively. The pooled ORs of hospital mortality and/or 90-day mortality among patients undergoing cardiac transplantation with AKI and AKI requiring RRT were 3.46 (95% CI, 2.40-4.97) and 13.05 (95% CI, 6.89-24.70), respectively. The pooled ORs of 1-year mortality among patients with AKI and AKI requiring RRT were 2.26 (95% CI, 1.56-3.26) and 3.89 (95% CI, 2.49-6.08), respectively. Conclusion: Among patients undergoing cardiac transplantation, the incidence of AKI and severe AKI requiring RRT are 47.1% and 11.8%, respectively. AKI post cardiac transplantation is associated with reduced short term and 1-year patient survival.

Invasive Hemodynamic Predictors of Renal Outcomes after Percutaneous Coronary Interventions

Objectives: To determine the association of right heart invasive hemodynamic parameters with post-percutaneous coronary intervention (PCI) acute kidney injury (AKI). Background: AKI after PCI is associated with a high morbidity and mortality. Various mechanisms are implicated in AKI after PCI. However, the association between filling pressures and invasive hemodynamic measures of right heart function with post-PCI AKI has not been described. Methods: This is a retrospective single-center analysis of patients of who underwent simultaneous right heart catheterization (RHC) and left heart catheterization with PCI at the Einstein Medical Center, Philadelphia, between January 2010 and December 2016. We included patients who had hemodynamic parameters from the concomitant RHC as well as measurements of kidney function up to 1 month after the procedure. We excluded patients with ST elevation myocardial infarction, end-stage renal disease, cardiogenic shock, and PCI with a need for mechanical circulatory device support. Multivariate linear regression analysis was used to analyze the association between the various right ventricular hemodynamic parameters and eGFR within 1 week and 1 month after catheterization after adjusting for age, race, gender, diabetes and hypertension, contrast volume, cardiac index, and baseline eGFR. Results: Right atrial (RA) pressure was inversely associated with eGFR within 1 week (β = –1.66; 95% CI –3.06 to –0.25; p = 0.021) and 1 month after PCI (β = –2.14; 95% CI –4.08 to –0.20; p = 0.031). Conclusion: Elevated RA pressure is associated with a worsening kidney function after cardiac catheterization and PCI.

Acute kidney injury following left ventricular assist device implantation: Contemporary insights and future perspectives

Currently, an increasing number of patients with end-stage heart failure are being treated with left ventricular assist device (LVAD) therapy as bridge-to-transplantation, bridge-to-candidacy, or destination therapy (DT). Potential life-threatening complications may occur, specifically in the early post-operative phase, which positions LVAD implantation as a high-risk surgical procedure. Acute kidney injury (AKI) is a frequently observed complication after LVAD implantation and is associated with high morbidity and mortality. The rapidly growing number of LVAD implantations necessitates better approaches of identifying high-risk patients, optimizing peri-operative management, and preventing severe complications such as AKI. This holds especially true for those patients receiving an LVAD as DT, who are typically older (with higher burden of comorbidities) with impaired renal function and at increased post-operative risk. Herein we outline the definition, diagnosis, frequency, pathophysiology, and risk factors for AKI in patients with an LVAD. We also review possible strategies to prevent and manage AKI in this patient population.

Associations between tricuspid annular plane systolic excursion to reflect right ventricular function and acute kidney injury in critically ill patients: a SICS-I sub-study

BACKGROUND

Acute kidney injury (AKI) occurs in up to 50% of all critically ill patients and hemodynamic abnormalities are assumed to contribute, but their nature and share is still unclear. We explored the associations between hemodynamic variables, including cardiac index and right ventricular function, and the occurrence of AKI in critically ill patients.

METHODS

In this prospective cohort study, we included all patients acutely admitted to an intensive care unit (ICU). Within 24 h after ICU admission clinical and hemodynamic variables were registered including ultrasonographic measurements of cardiac index and right ventricular function, assessed using tricuspid annular plane systolic excursion (TAPSE) and right ventricular systolic excursion (RV S'). Maximum AKI stage was assessed according to the KDIGO criteria during the first 72 h after admission. Multivariable logistic regression modeling was used including both known predictors and univariable significant predictors of AKI. Secondary outcomes were days alive outside ICU and 90-day mortality.

RESULTS

A total of 622 patients were included, of which 338 patients (54%) had at least AKI stage 1 within 72 h after ICU admission. In the final multivariate model higher age (OR 1.01, 95% CI 1.00-1.03, for each year), higher weight (OR 1.03 CI 1.02-1.04, for each kg), higher APACHE IV score (OR 1.02, CI 1.01-1.03, per point), lower mean arterial pressure (OR 1.02, CI 1.01-1.03, for each mmHg decrease) and lower TAPSE (OR 1.05, CI 1.02-1.09 per millimeter decrease) were all independent predictors for AKI in the final multivariate logistic regression model. Sepsis, cardiac index, RV S' and use of vasopressors were not significantly associated with AKI in our data. AKI patients had fewer days alive outside of ICU, and their mortality rate was significantly higher than those without AKI.

CONCLUSIONS

In our cohort of acutely admitted ICU patients, the incidence of AKI was 54%. Hemodynamic variables were significantly different between patients with and without AKI. A worse right ventricle function was associated with AKI in the final model, whereas cardiac index was not.