Changes in renal function after implantation of continuous-flow left ventricular assist devices

Impact of Continuous Flow Left Ventricular Assist Device Therapy on Chronic Kidney Disease: A Longitudinal Multicenter Study

BACKGROUND

Many patients undergoing durable left ventricular assist device (LVAD) implantation suffer from chronic kidney disease (CKD). Therefore, we investigated the effect of LVAD support on CKD.

METHODS

A retrospective multicenter cohort study, including all patients undergoing LVAD (HeartMate II (n = 330), HeartMate 3 (n = 22) and HeartWare (n = 48) implantation. In total, 227 (56.8%) patients were implanted as bridge-to-transplantation; 154 (38.5%) as destination therapy; and 19 (4.7%) as bridge-to-decision. Serum creatinine measurements were collected over a 2-year follow-up period. Patients were stratified based on CKD stage.

RESULTS

Overall, 400 patients (mean age 53 ± 14 years, 75% male) were included: 186 (46.5%) patients had CKD stage 1 or 2; 93 (23.3%) had CKD stage 3a; 82 (20.5%) had CKD stage 3b; and 39 (9.8%) had CKD stage 4 or 5 prior to LVAD implantation. During a median follow-up of 179 days (IQR 28-627), 32,629 creatinine measurements were available. Improvement of kidney function was noticed in every preoperative CKD-stage group. Following this improvement, estimated glomerular filtration rates regressed to baseline values for all CKD stages. Patients showing early renal function improvement were younger and in worse preoperative condition. Moreover, survival rates were higher in patients showing early improvement (69% vs 56%, log-rank P = 0 .013).

CONCLUSIONS

Renal function following LVAD implantation is characterized by improvement, steady state and subsequent deterioration. Patients who showed early renal function improvement were in worse preoperative condition, however, and had higher survival rates at 2 years of follow-up.

Cystatin C- Versus Creatinine-Based Assessment of Renal Function and Prediction of Early Outcomes Among Patients With a Left Ventricular Assist Device

BACKGROUND

Estimated glomerular filtration rate (eGFR) based on serum creatinine (sCr) improves early after left ventricular assist device (LVAD) implantation but subsequently declines. Although sCr is a commonly accepted clinical standard, cystatin C (CysC) has shown superiority in assessment of renal function in disease states characterized by muscle wasting. Among patients with an LVAD, we aimed to (1) longitudinally compare CysC-eGFR and sCr-eGFR, (2) assess their predictive value for early postoperative outcomes, and (3) investigate mechanisms which might explain potential discrepancies.

METHODS

A prospective cohort (n=116) with CysC and sCr concurrently measured at serial time points, and a retrospective cohort (n=91) with chest computed tomography performed within 40 days post-LVAD were studied. In the prospective cohort, the primary end point was a composite of in-hospital mortality, renal replacement therapy, or severe right ventricular failure. In the retrospective cohort, muscle mass was estimated using pectoralis muscle area indexed to body surface area (pectoralis muscle index).

RESULTS

In the prospective cohort, sCr-eGFR significantly improved early post-LVAD and subsequently declined, whereas CysC-eGFR remained stable. CysC-eGFR but not sCr-eGFR predicted the primary end point: odds ratio per 5 mL/(min·1.73 m²) decrease 1.16 (1.02-1.31) versus 0.99 (0.94-1.05). In retrospective cohort, for every 5 days post-LVAD, a 6% decrease in pectoralis muscle index was observed (95% CI, 2%-9%, P=0.003). After adjusting for time on LVAD, for every 1 cm²/m² decrease in pectoralis muscle index, there was a 4% decrease in 30-day post-LVAD sCr (95% CI, 1%-6%, P=0.004).

CONCLUSIONS

Initial improvement in sCr-eGFR is likely due to muscle wasting following LVAD surgery. CysC may improve assessment of renal function and prediction of early postoperative outcomes in patients with an LVAD.

Renal Outcomes in Patients Bridged to Heart Transplant With a Left Ventricular Assist Device

BACKGROUND

Patients with end-stage heart failure are increasingly being bridged to heart transplant (BTT) with mechanical circulatory support; however the association between a left ventricular assist device (LVAD) BTT strategy and posttransplant renal outcomes is unclear. The aim of this study was to analyze the association of LVAD BTT with the development of posttransplant renal failure using a large national registry.

METHODS

We queried the 2009 to 2018 United Network for Organ Sharing registry for all adults undergoing first-time heart or heart-kidney transplantation and stratified patients by use of pretransplant durable LVAD. The primary outcome of interest was posttransplant renal failure, which was evaluated with multivariable logistic regression.

RESULTS

Of 18,307 patients meeting inclusion criteria, 7887 were (43%) and 10,420 were not (57%) BTT with an LVAD. BTT patients had slightly better baseline renal function (estimated glomerular filtration rate, 68.7 vs 65.8 mL/min, P < .001) and were less likely to receive a heart-kidney transplant (2.7% vs 4.8%, P < .001). On multivariable logistic regression, LVAD BTT strategy was not independently associated with posttransplant renal failure (odds ratio, 1.13; 95% confidence interval, 0.86-1.49). Similarly LVAD BTT among patients with preoperative renal dysfunction was not associated with posttransplant renal failure (adjusted odds ratio, 1.40; 95% confidence interval, 0.91-2.18).

CONCLUSIONS

BTT with an LVAD does not appear to be associated with worse renal outcomes regardless of baseline renal function. Furthermore, an LVAD BTT strategy in patients with chronic kidney disease may enable clinicians to identify candidates suitable for isolated heart transplantation without increasing their risk for posttransplant renal failure.

Mesangioproliferative glomerulonephritis with extracapillary crescents - unexpected fatal complication in a 17-year-old patient with implanted left ventricular assist device

The continuous flow left ventricular assist device (cf-LVAD) is the life-saving solution for patients with end-stage global heart failure. We present the case of a young patient with biventricular dilated cardiomyopathy, who had a cf-LVAD implantation and died as result of progressive renal failure. In the first year after implantation, he suffered repeated strokes and episodes of pneumonia with Klebsiella pneumoniae and Escherichia coli. The patient had hypertension, which was kept under control with angiotensin-converting enzyme (ACE) inhibitors and beta-blockers. After multiple bleeding episodes, the patient died at 21 months after the LVAD implant. At autopsy, parenchymatous brain hemorrhage was found to be associated with pulmonary hemorrhages. The unexpected features related to mesangioproliferative and extracapillary glomerulonephritis, with focal glomerulosclerosis. The proliferated parietal cells of Bowman’s capsule proved to express cluster of differentiation 44 (CD44), whereas remnant podocytes and mesangial cells showed Wilms tumor 1 (WT1) positivity. Since CD44 might be involved in fibrogenesis, but ACE inhibitors can exert a protective role against glomerular deterioration, we performed a synthesis of literature data which enabled us to propose a hypothesis with a potential clinical impact. We conclude that, in patients with LVAD implants, high blood pressure and high serum level of angiotensin II, the association between ACE inhibitors and anti-CD44 agents might exert glomerular protection and increase the survival time. Experimental studies are necessary to support our hypothesis and to explain the mechanism of possible glomerulopathy installed after LVAD implant.

Durable left ventricular assist device support as a bridge to heart transplant candidacy†

OBJECTIVES

Left ventricular assist devices are funded in the UK exclusively as a bridge to transplant (BTT). However, patients who potentially could receive a transplant may develop reversible contraindications to transplant. Bridge to candidacy (BTC) has sometimes been controversial, given the uncertain clinical efficacy of BTC and the risk that reimbursement could be denied. We analysed the UK ventricular assist device database to understand how common BTC was and to assess patient survival rates and incidences of transplants.

METHODS

We identified BTC implants in patients with pulmonary hypertension, chronic kidney disease and obesity using the UK guidelines for heart transplants.

RESULTS

A total of 306 of 540 patients had complete data and 157 were identified as BTC (51%). Overall, there was no difference in survival rates between patients designated as BTC and those designated at BTT (71.9 vs 72.9% at 1 year, respectively; P = 0.82). However, the survival rate was lower at all time points in those with an estimated glomerular filtration rate (eGFR) <40 and in patients with a body mass index (BMI) >32 up to 1-year postimplant. There were no significant differences in the incidence of transplant between patients who were BTC and BTT or for any subgroup up to 5 years. However, we noted a diverging trend towards a lower cumulative incidence of transplant for patients with a BMI >32.

CONCLUSIONS

BTC is common in the UK and appears clinically effective, given that the survival rates and the incidence of transplants were comparable with those for BTT. Patients with a high BMI have a worse survival rate through to 1 year and a trend for a lower incidence of a transplant. Patients with a low eGFR also have a worse survival rate, but a similar proportion received transplants.

Non-invasive assessment of arterial pulsatility in patients with continuous-flow left ventricular assist devices

INTRODUCTION

Long-term use of continuous-flow left ventricular assist devices may have negative consequences for autonomic, cardiovascular and gastrointestinal function. It has thus been suggested that non-invasive monitoring of arterial pulsatility in patients with a left ventricular assist device is highly important for ensuring patient safety and longevity. We have developed a novel, semi-automated frequency-domain-based index of arterial pulsatility that is obtained during suprasystolic occlusions of the upper arm: the 'cuff pulsatility index'.

PURPOSE

The purpose of this study was to evaluate the relationship between the cuff pulsatility index and invasively determined arterial pulsatility in patients with a left ventricular assist device.

METHODS

Twenty-three patients with a left ventricular assist device with end-stage heart failure (six females: age = 65 ± 9 years; body mass index = 30.5 ± 3.7 kg m^-2) were recruited for this study. Suprasystolic occlusions were performed on the upper arm of the patient's dominant side, from which the cuff pressure waveform was obtained. Arterial blood pressure was obtained from the radial artery on the contralateral arm. Measurements were obtained in triplicate. The relationship between the cuff pressure and arterial blood pressure waveforms was assessed in the frequency-domain using coherence analysis. A mixed-effects approach was used to assess the relationship between cuff pulsatility index and invasively determined arterial pulsatility (i.e. pulse pressure).

RESULTS

The cuff pressure and arterial blood pressure waveforms demonstrated a high coherence up to the fifth harmonic of the cardiac frequency (heart rate). The cuff pulsatility index accurately tracked changes in arterial pulse pressure within a given patient across repeated measurements.

CONCLUSIONS

The cuff pulsatility index shows promise as a non-invasive index for monitoring residual arterial pulsatility in patients with a left ventricular assist device across time.

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.

Benefits of Neurohormonal Therapy in Patients With Continuous-Flow Left Ventricular Assist Devices

Left ventricular assist devices (LVADs) have dramatically improved short-term outcomes among patients with advanced heart failure. While neurohormonal blockade (NHB) is the cornerstone of treatment for patients with heart failure with reduced ejection fraction, its effect after LVAD placement has not been established. We reviewed medical records of 307 patients who underwent primary LVAD implantation from January 2006 to September 2015 at two institutions in the United States. Patients were followed for at least 2 years post-LVAD implantation or until explantation, heart transplantation, or death. Cox regression analysis stratifying on center was used to assess associations with mortality. Neurohormonal blockade use was treated as a time-dependent predictor. Stepwise selection indicated treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ACEIs/ARBs) (hazard ratio [HR] = 0.53 [0.30-0.95], p = 0.03), age at the time of implantation (HR = 1.28 [1.05-1.56] per decade, p = 0.02), length of stay postimplantation (HR = 1.16 [1.11-1.21] per week, p < 0.01) and INTERMACS profile of 1 or 2 (HR = 1.86 [1.17-2.97], p < 0.01) were independent predictors of mortality. In this large, retrospective study, treatment with ACEIs or ARBs was an independent factor associated with decreased mortality post-LVAD placement.

Predictors and Outcomes of Renal Replacement Therapy After Left Ventricular Assist Device Implantation

OBJECTIVE

To examine the frequency and outcomes of patients requiring renal replacement therapy (RRT) early after left ventricular assist device (LVAD) implantation.

PATIENTS AND METHODS

We examined use of in-hospital RRT and outcomes in consecutive adults who underwent continuous-flow LVAD implantation from February 15, 2007, through August 8, 2017. Logistic regression was used to examine predictors of RRT. The associations of RRT with outcomes were examined using Cox proportional hazards regression.

RESULTS

Of 354 patients who underwent LVAD implantation, 54 (15%) required in-hospital RRT. Patients receiving RRT had higher preoperative Charlson Comorbidity Index values (median, 5 vs 4; P=.03), Model for End-Stage Liver Disease scores (mean, 19.0 vs 14.5; P<.001), right atrial pressure (mean, 19.1 vs 13.4 mm Hg; P<.001), and estimated 24-hour urine protein levels (median, 357 vs 174 mg; P<.001) and lower preoperative estimated glomerular filtration rate (eGFR) (median, 43 vs 57 mL/min; P<.001) and measured GFR using ¹²⁵I-iothalamate clearance (median, 33 vs 51 mL/min; P=.001) than those who did not require RRT. Approximately 40% of patients with eGFR less than 45 mL/min/1.73 m² and 24-hour urine protein level greater than 400 mg required RRT vs 6% with eGFR greater than45 mL/min/1.73 m² and without significant proteinuria. Lower preoperative eGFR, higher estimated 24-hour urine protein level, higher right atrial pressure, and longer cardiopulmonary bypass time were independent predictors of RRT after LVAD implantation. Of patients requiring in-hospital RRT, 18 (33%) had renal recovery, 18 (33%) required outpatient hemodialysis, and 18 (33%) died before hospital discharge. After median (Q1, Q3) follow-up of 24.3 (8.9, 49.6) months, RRT was associated with increased risk of death (adjusted hazard ratio [HR], 2.86; 95% CI, 1.90-4.33; P<.001) and gastrointestinal bleeding (adjusted HR, 4.47; 95% CI, 2.57-7.75; P<.001).

CONCLUSION

In-hospital RRT is associated with poor prognosis after LVAD. A detailed preoperative assessment of renal function before LVAD may be helpful in risk stratification and patient selection.

Impact of chronic kidney disease on in-hospital outcomes following left ventricular assist device placement: A national perspective

BACKGROUND

Left ventricular assist devices (LVADs) are being increasingly utilized for the treatment of stage-D heart failure. A LVAD is a battery-operated, mechanical pump that assists in pumping blood out of the left ventricle (LV) into the aorta, thereby lowering left ventricular burden. Prevalence of chronic kidney disease (CKD) is increasing in patients receiving LVAD.

OBJECTIVES

The purpose of this study was to compare in-hospital mortality and hospitalization expenditure associated with CKD in patients receiving LVAD implantation.

METHODS

Using the National Inpatient Sample from January 2012 through September 2015, index hospitalizations for LVAD were identified. Based on kidney function, LVAD recipients were divided into three groups: Group 1 included patients with normal renal function or CKD stages I-III. Groups 2 and 3 comprised of patients with CKD stage IV/V, and end-stage renal disease on dialysis respectively.

RESULTS

A total of 20,656 patients received LVAD during the study period. Mean age was 56.1 years; 76.8% were men. In a fully adjusted model, in-hospital mortality was higher in group 2 (OR: 1.33, CI: 1.16-1.50) and highest in group 3 (OR: 8.95, CI: 6.90-11.61). Similarly, the length of hospitalization, and hospitalization cost were higher in group 2 and highest in group 3.

CONCLUSION

Despite improving outcomes in patients receiving LVAD, CKD remained a significant health problem. Worsening in-hospital outcomes paralleling the degree of kidney dysfunction were observed in patients receiving LVADs in this study.

Outcomes after left ventricular assist device implantation in patients with acute kidney injury

OBJECTIVE

The study objective was to compare outcomes for patients with and without acute kidney injury during hospitalizations when left ventricular assist devices are implanted.

METHODS

By using the National Inpatient Sample from 2008 to 2013, we identified patients with an International Classification of Diseases, Ninth Revision procedure code for left ventricular assist device implantation (37.66). We ascertained the presence of acute kidney injury and acute kidney injury requiring dialysis using validated International Classification of Diseases, Ninth Revision codes. We used logistic regression to examine the association of nondialysis-requiring acute kidney injury and acute kidney injury requiring dialysis with mortality, procedural complications, and discharge destination.

RESULTS

We identified 8362 patients who underwent left ventricular assist device implantation, of whom 3760 (45.0%) experienced nondialysis-requiring acute kidney injury and 426 (5.1%) experienced acute kidney injury requiring dialysis. In-hospital mortality was 3.9% for patients without acute kidney injury, 12.2% for patients with nondialysis-requiring acute kidney injury, and 47.4% for patients with acute kidney injury requiring dialysis. Patients with nondialysis-requiring acute kidney injury and acute kidney injury requiring dialysis had higher adjusted odds of mortality (3.24, 95% confidence interval [CI], 2.04-5.13 and 20.8, 95% CI, 9.7-44.2), major bleeding (1.38, 95% CI, 1.08-1.77 and 2.44, 95% CI, 1.47-4.04), sepsis (2.69, 95% CI, 1.93-3.75 and 5.75, 95% CI, 3.46-9.56), and discharge to a nursing facility (2.15, 95% CI, 1.51-3.07 and 5.89, 95% CI, 2.67-12.99).

CONCLUSIONS

More than 1 in 10 patients with acute kidney injury and approximately 1 in 2 patients with acute kidney injury requiring dialysis died during their hospitalization, with only 30% of patients with acute kidney injury requiring dialysis discharged to home. This information is necessary to support shared decision-making for patients with advanced heart failure and acute kidney injury.

Biomarkers of Inflammation, Fibrosis, and Acute Kidney Injury in Patients with Heart Failure with and without Left Ventricular Assist Device Implantation

BACKGROUND/AIMS

Renal dysfunction or renal failure is a common complication in left ventricular assist device (LVAD) recipients and is associated with reduced survival. To date, serum creatinine and glomerular filtration rate (GFR) are used for the evaluation of kidney function. However, serum creatinine and GFR have limitations. The objective of our study is to assess the levels of kidney biomarkers in LVAD recipients compared to heart failure patients and healthy controls and to examine their association with conventional clinical biomarkers.

METHODS

The biomarkers neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), plasminogen activator inhibitor-1 (PAI-1), and adiponectin were assessed in 51 participants: 19 heart failure patients, 16 LVAD recipients, and 16 healthy controls. Linear regressions were performed to assess whether demographic and clinical variables predict the levels of biomarkers that are associated with acute kidney injury and the risk of chronic kidney disease.

RESULTS

The levels of NGAL and adiponectin were higher in LVAD recipients and patients with heart failure as compared with healthy controls. The levels of PAI-1 and KIM-1 were not elevated in LVAD recipients. The results of linear regression analysis indicated that when controlling for the effect of CRP and BNP, 40.1% of the variance in NGAL levels can be explained by GFR (R2 = 0.401, F = 5.56, p = 0.005), while CRP can explain 35.3% of the variance in adiponectin levels (R2 = 0.353, F = 4.55, p = 0.01), when controlling for the effect of BNP and GFR.

CONCLUSIONS

The levels of NGAL and adiponectin were augmented in LVAD recipients, suggesting that renal functions were not restored with circulatory support. Larger studies should assess the predictability of these biomarkers of renal dysfunction in LVAD recipients.

Outcomes of Moderate-to-Severe Acute Kidney Injury following Left Ventricular Assist Device Implantation

BACKGROUND

Although acute kidney injury (AKI) is a common complication following cardiac surgery, less is known about the occurrence and consequences of moderate/severe AKI following left ventricular assist device (LVAD) implantation.

METHODS

All patients who had an LVAD implanted at our center from 2008 to 2016 were reviewed to determine the incidence of, and risk factors for, moderate/severe (stage 2/3) AKI and to compare postoperative complications and mortality rates between those with and those without moderate/severe AKI.

RESULTS

Of 246 patients, 68 (28%) developed moderate/severe AKI. A multivariable logistic regression comprising body mass index and prior sternotomy had fair predictive ability (area under the curve = 0.71). A 1-unit increase in body mass index increased the risk of moderate/severe AKI by 7% (odds ratio = 1.07; 95% confidence interval: 1.03-1.11); a prior sternotomy increased the risk more than 3-fold (odds ratio = 3.4; 95% confidence interval: 1.84-6.43). The group of patients with moderate/severe AKI had higher rates of respiratory failure and death than the group of patients with mild/no AKI. Patients with moderate/severe AKI were at 3.2 (95% confidence interval: 1.2-8.2) times the risk of 30-day mortality compared to those without. Even after adjusting for age and Interagency Registry for Mechanically Assisted Circulatory Support profile, those with moderate/severe AKI had 1.75 (95% confidence interval: 1.03-3.0) times the risk of 1-year mortality compared to those without.

DISCUSSION

Risk-stratifying patients prior to LVAD placement in regard to AKI development may be a step toward improving surgical outcomes.

Advanced Heart Failure Therapies and Cardiorenal Syndrome

Heart failure (HF) is extremely prevalent and for those with end-stage (stage D) disease, 1-year survival is only 25-50%. Several studies have captured the mortality impact of kidney disease on patients with HF, and measures of kidney function are a component of many HF risk stratification scores. The management of advanced HF complicated by cardiorenal syndrome (CRS) is challenging, and irreversible kidney failure often limits patient candidacy for advanced HF therapies, such as transplant or left ventricular assist device therapy. Thus, prompt institution of aggressive therapy is warranted in stage D HF patients with CRS to prevent irreversible kidney failure. In this chapter, we discuss the assessment and management of patients with CRS with end-stage HF. In addition to discussing medical therapy aimed at decongestion and increased cardiac inotropy, we provide a summary of temporary circulatory support devices that can be considered for those whom hospice is not desired. In all circumstances, a close collaboration between the advanced HF specialist and nephrologist is needed to achieve the best patient outcomes.

Risk of severe primary graft dysfunction in patients bridged to heart transplantation with continuous-flow left ventricular assist devices

BACKGROUND

Primary graft dysfunction (PGD) remains a significant cause of post-transplant morbidity and mortality. The exact mechanism and risk factors for this phenomenon remain unknown in the contemporary era.

METHODS

In this study we reviewed adult patients undergoing heart transplantation (HT) at our institution between 2009 and 2017. Severe PGD was defined as the need for mechanical circulatory support (MCS) within the first 24 hours after HT. Multivariate logistic regression analysis was used to identify risk factors for severe PGD, focusing on those bridged to transplant (BTT) with a continuous-flow left ventricular assist device (CF-LVAD).

RESULTS

Fifty-six of 480 (11.7%) HT patients experienced severe PGD. Eighty percent of the severe PGD patients were BTT with a CF-LVAD (odds ratio [OR] 3.86, 95% confidence interval [CI] 1.94 to 7.68, p < 0.001). Among the BTT patients, significant associations between >1 year of CF-LVAD support (OR 2.48, 95% CI 1.14 to 5.40, p = 0.022), pre-HT creatinine (OR 3.35, 95% CI 1.42 to 7.92, p = 0.006), elevated central venous pressure/pulmonary capillary wedge pressure (CVP/PCWP) ratio (OR 3.32, 95% CI 1.04 to 10.60, p = 0.043), use of amiodarone before HT (OR 2.69, 95% CI 1.20 to 6.20, p = 0.022), and severe PGD were identified. RADIAL score did not accurately predict severe PGD in this contemporary cohort. Those patients who developed severe PGD had decreased 1-year post-transplant survival (78.3% vs 91.8%, p = 0.007).

CONCLUSIONS

Use of CF-LVAD as BTT is associated with an increased risk of severe PGD. Increased time on device support, renal dysfunction, right ventricular dysfunction as assessed by CVP/PCWP ratio, and pre-transplant amiodarone may identify those patients at high risk. Further research is warranted focusing on optimal timing of device implantation and transplantation, as well as the underlying mechanisms of PGD.

Changes in renal function after left ventricular assist device placement in pediatric patients: A Pedimacs analysis

BACKGROUND

Renal dysfunction (RD) is prevalent among pediatric patients with advanced heart failure. Data are limited regarding changes in renal function after left ventricular assist device (LVAD) placement in this population.

METHODS

Pediatric LVAD recipients enrolled in the Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) between September 19, 2012 and June 30, 2016 were included. Longitudinal changes in renal function were analyzed for the entire cohort as well as subgroups stratified by patient and device characteristics. Logistic regression was used to attempt to identify factors associated with lack of improvement in renal function after LVAD placement. Post-LVAD outcomes were assessed using the Kaplan‒Meier method.

RESULTS

Data from 247 patients from 39 centers were analyzed. Baseline RD (estimated glomerular filtration rate [eGFR] <90 ml/min/1.73 m²) was present in 150 (61%) patients. Overall, eGFR improved post-LVAD, peaking at 1 month post-implant. There was an inverse relationship between baseline eGFR and the degree of improvement at 1 month. Degree of improvement in eGFR at 1 month was not impacted by device type, age, Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile, or diagnosis. Failure to normalize renal function at 1 week was correlated with persistent RD at 1 month. Post-implant outcomes did not differ among patients stratified by pre-implant renal function.

CONCLUSIONS

Renal function improves post-LVAD placement in pediatric patients regardless of age, diagnosis, illness severity, or device type, with improvement most pronounced in patients with baseline RD. Identifying patients with irreversible renal dysfunction before LVAD placement remains difficult. Pre-LVAD renal function does not appear to impact survival to transplant.

Preoperative renal dysfunction does not affect outcomes of left ventricular assist device implantation

OBJECTIVE

Selection criteria for durable left ventricular assist device (LVAD) implantation remain unclear. One such criterion is renal function. In this study we evaluated outcomes of LVAD implantation in patients with preoperative renal dysfunction.

METHODS

Patients with implanted LVADs as destination therapy (DT) or bridge to transplantation (BTT) at a single institution between 2006 and 2015 were included. Primary stratification was according to pre-implantation glomerular filtration rate (GFR): >60 mL/min versus <60 mL/min or dialysis dependence. The primary outcome was post-LVAD implantation overall survival.

RESULTS

Two hundred thirty-eight patients underwent LVAD implantation during the study period as DT (60%; n = 142) or BTT (40%; n = 96). Reduced GFR was present in 56% (n = 132), with 8% (n = 18) being dialysis-dependent. Normal versus reduced GFR cohorts were well matched except for a higher incidence of coronary artery disease in the patients with reduced GFR (61% vs 48%; P = .04). Mean follow-up was 13.5 ± 17.0 months. Unadjusted and risk-adjusted survival at 1, 3, 6, and 12 months after LVAD implantation were similar between the cohorts for DT and BTT. Rates of transplantation were comparable in BTT patients (61% normal vs 53% reduced GFR; P = .43). Recovery of renal function to a GFR >60 mL/min occurred in 43% (n = 17) and 57% (n = 42) of patients with reduced GFR in the BTT and DT cohorts, respectively, by 1 year post implantation.

CONCLUSIONS

Well selected patients with preexisting renal dysfunction can undergo LVAD implantation with acceptable outcomes. Approximately half of LVAD recipients with preimplantation renal dysfunction will recover normal renal function within the first postoperative year. Renal dysfunction alone should not serve as an absolute contraindication to LVAD therapy.

Prognostic relevance of hemodialysis for short-term survival in patients after LVAD implantation

End-stage heart failure (HF) is associated with renal failure (RF). This study aimed to determine the prognostic influence of RF and post-operative hemodialysis on short-term survival following left ventricular assist device (LVAD) implantation. This retrospective study includes 68 patients undergoing LVAD treatment. Kidney function was recorded prior to LVAD implantation, immediately afterwards and after 30 days, noting the need for hemodialysis. Median pre-operative Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) classification was 3.47 ± 1.08. 30 days after implantation there was a significant improvement of estimated glomerular filtration rate (eGFR) and reduction of blood urea nitrogen (BUN). Of pre-operative RF parameters, BUN was associated with increased mortality and need for early post-operative hemodialysis. Post-operative hemodialysis was associated with significantly lower short-term survival, while pre-operative hemodialysis did not impact mortality. Post-operative acute kidney injury (AKI) requiring hemodialysis can be regarded as a strong negative prognostic marker for short-term survival. The absence of a clear correlation between most routine RF parameters and survival or the need for early post-operative hemodialysis calls into question the predictive value of pre-operative RF. The negative association of only post-operative hemodialysis on short-term survival emphasises the impact of the occurrence of AKI.

Living Without a Pulse: The Vascular Implications of Continuous-Flow Left Ventricular Assist Devices

Pulsatility seems to have a teleological role because evolutionary hierarchy favors higher ordered animals with more complex, multichamber circulatory systems that generate higher pulse pressure compared with lower ordered animals. Yet despite years of such natural selection, the modern generation of continuous-flow left ventricular assist devices (CF-LVADs) that have been increasingly used for the last decade have created a unique physiology characterized by a nonpulsatile, nonlaminar blood flow profile with the absence of the usual large elastic artery Windkessel effect during diastole. Although outcomes and durability have improved with CF-LVADs, patients supported with CF-LVADs have a high rate of complications that were not as frequently observed with older pulsatile devices, including gastrointestinal bleeding from arteriovenous malformations, pump thrombosis, and stroke. Given the apparent fundamental biological role of the pulse, the purpose of this review is to describe the normal physiology of ventricular-arterial coupling from pulsatile flow, the effects of heart failure on this physiology and the vasculature, and to examine the effects of nonpulsatile blood flow on the vascular system and potential role in complications seen with CF-LVAD therapy. Understanding these concomitant vascular changes with CF-LVADs may be a key step in improving patient outcomes as modulation of pulsatility and flow characteristics may serve as a novel, yet simple, therapy for reducing complications.

Successful establishment of a left ventricular assist device program in an emerging country: one year experience

Background

The primary goal of this study was to evaluate the outcomes of patients with end-stage heart failure (HF) who underwent continuous flow left ventricular assist device (CF-LVAD) in a developing country and to compare to those reported by more developed countries. The secondary goal was on determining factors that may be connected to improved survival.

Methods

We prospectively analyzed 47 consecutive patients who underwent CF-LVAD at our institution. After one year the survival and adverse event profiles of patients were evaluated. At 3, 6 and 12 months, the cardiac, renal and liver function outcomes were assessed.

Results

The 30-day, 6-month and 1-year survival rates were 89%, 85% and 80%, respectively. A significant improvement in dimensions and ejection fraction of left ventricle, BNP, functional capacity, blood urea nitrogen (BUN) and total bilirubin (P<0.05 for all) were noticed 3 months post-CF-LVAD implantation, and patients were stable throughout the entire first year follow up. In the group of patients with baseline renal dysfunction (RD) there were significant improvements of renal function (P=0.004), with no changes on follow up. 57% of patients exhibited some kind of adverse event, commonly in the form of bleeding. In multivariate Cox regression analysis renal failure was found to be as an independent risk factor for the overall survival (HR =13.1, P<0.001).

Conclusions

In conclusion, our data extends previous findings from centers of developed countries, that CF-LVAD is an adequate treatment option for patients suffering from end-stage HF, and encourages expansion of CF-LVAD implantation in developing countries with nascent HT program.

Therapeutic Approach to Patients with Heart Failure with Reduced Ejection Fraction and End-stage Renal Disease

BACKGROUND

Several risk factors including Ischemic heart disease, uncontrolled hypertension, high output Heart Failure (HF) from shunting through vascular hemodialysis access, and anemia, contribute to development of HF in patients with End-Stage Renal Disease (ESRD). Guidelinedirected medical and device therapy for Heart Failure with Reduced Ejection Fraction (HFrEF) has not been extensively studied and may have limited safety and efficacy in patients with ESRD.

RESULTS

Maintenance of interdialytic and intradialytic euvolemia is a key component of HF management in these patients but often difficult to achieve. Beta-blockers, especially carvedilol which is poorly dialyzed is associated with cardiovascular benefit in this population. Despite paucity of data, Angiotensin-converting Enzyme Inhibitors (ACEI) or Angiotensin II Receptor Blockers (ARBs) when appropriately adjusted by dose and with close monitoring of serum potassium can also be administered to these patients who tolerate beta-blockers. Mineralocorticoid receptors in patients with HFrEF and ESRD have been shown to reduce mortality in a large randomized controlled trial without any significantly increased risk of hyperkalemia. Implantable Cardiac-defibrillators (ICDs) should be considered for primary prevention of sudden cardiac death in patients with HFrEF and ESRD who meet the implant indications. Furthermore in anemic iron-deficient patients, intravenous iron infusion may improve functional status. Finally, mechanical circulatory support with leftventricular assist devices may be related to increased mortality risk and the presence of ESRD poses a relative contraindication to further evaluation of these devices.

Left Ventricular Assist Devices and the Kidney

Left ventricular assist devices (LVADs) are common and implantation carries risk of AKI. LVADs are used as a bridge to heart transplantation or as destination therapy. Patients with refractory heart failure that develop chronic cardiorenal syndrome and CKD often improve after LVAD placement. Nevertheless, reversibility of CKD is hard to predict. After LVAD placement, significant GFR increases may be followed by a late return to near baseline GFR levels, and in some patients, a decline in GFR. In this review, we discuss changes in GFR after LVAD placement, the incidence of AKI and associated mortality after LVAD placement, the management of AKI requiring RRT, and lastly, we review salient features about cardiorenal syndrome learned from the LVAD experience. In light of the growing number of patients using LVADs as a destination therapy, it is important to understand the effect of these devices on the kidney. Additional research and long-term data are required to better understand the relationship between the LVAD and the kidney.

Heart transplantation versus left ventricular assist devices as destination therapy or bridge to transplantation for 1-year mortality: a systematic review and meta-analysis

Background

The optimal treatment for advanced heart failure (HF) patients with regards to mortality remains unknown. Heart transplantation (HTx) and left ventricular assist devices (LVAD) used either as a bridge to transplant (BTT) or destination therapy (DT) have been compared in a number of studies, without definite conclusions with regards to mortality benefit. We sought to systematically review the pertinent literature and perform a meta-analysis of all the available studies presenting head-to-head comparisons between HTx and LVAD BTT or LVAD DT for late (>6 months) all-cause mortality.

Methods

We performed a systematic search of Medline and Cochrane Central databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We conducted a meta-analysis of late mortality comparing HTx vs. BTT LVAD and HTx vs. DT LVAD using a random effects model.

Results

Eight studies were included in our meta-analysis, reporting data on 7,957 patients in total. Although the available studies are of high quality [8 stars in Newcastle-Ottawa Scale (NOS) on average], there is paucity of mortality data. Specifically, seven studies compared HTx with BTT and five studies compared HTx with DT for 1-year mortality. Our pooled estimates showed that there was no difference in late mortality among these strategies.

Conclusions

Our meta-analysis highlights the small number and the heterogeneity of available studies referring to the optimal invasive management of advanced HF, and shows that there are no differences between HTx and LVAD for these patients with regards to late mortality.

Renal Function Changes Following Left Ventricular Assist Device Implantation

Limited data assessing the clinical significance of post-left ventricular assist device (LVAD) in renal function are available. We aimed to investigate the impact of changes in renal function after LVAD implantation on subsequent long-term outcomes. We followed 184 patients with HeartMate II LVADs implanted between May 2008 and November 2014. Serial assessment of renal function, was performed at baseline and at day 1, day 7, 1 month, 3 months, 6 months, 1 year, and 2 years after implantation. Effects of 1-month GFR and changes in GFR from baseline to 1 month on long-term mortality and hospital re-admission were evaluated. There were 30 patients with GFR <45 (low), 44 with GFR 45 to 59 (intermediate), and 110 with GFR ≥60 (normal) at baseline. Only patients with baseline GFR <45 experienced significant improvement in GFR after 2 years of follow-up (p = 0.012). At 1 month, a higher GFR category was significantly associated with a 31% reduction in mortality (hazard ratio [HR] 0.69, CI 0.49 to 0.98, p = 0.036), but not re-admission. Patients with baseline low and intermediate GFR who had no improvement in renal function category at 1 month experienced significantly greater risk of mortality (HR 1.95, CI 1.10 to 3.43, p = 0.022) and re-admission (HR 1.75, CI 1.07 to 2.84, p = 0.025), relative to patients whose GFR was normal at baseline and 1 month. In conclusion, renal function after LVAD implantation improves in patients with GFR <45. Change in renal function from baseline to 1 month after implantation is a powerful marker of long-term outcomes.

A pilot study on the efficacy and safety of a minimally invasive surgical and anesthetic approach for ventricular assist device implantation

BACKGROUND

The aim of our study was to compare 2 surgical and anesthetic approaches during ventricular assist device implantation.

METHODS

68 patients (50.4 ± 17.1 years old) were supported with the HeartWare® HVAD (32 patients) and the Jarvik 2000 VAD (36 patients) between January 2010 and August 2016. Two surgical techniques were applied: a minimally invasive approach with the aid of paravertebral-block (mini-invasive group, 41 patients) and a standard-surgical-approach with the aid of general anesthesia (27 patients).

RESULTS

The minimally invasive approach allowed faster postoperative recovery by significantly reducing the duration of surgery (p<0.05), anesthesia (p<0.05), mechanical ventilation (p<0.05), inotropic support (p<0.05), ICU and in-hospital stay (p<0.05), and time to first mobilization (p<0.05). No case of epidural hematoma was observed. Eleven patients died (16%) at 30 days, 3 in the mini-invasive group (7.3%) and 8 in the invasive group (29.6%).

CONCLUSIONS

Minimally invasive approaches play a substantial role in VAD surgery by facilitating faster recovery, which is important for patients at very high risk.

Complications, Risk Factors, and Staffing Patterns for Noncardiac Surgery in Patients with Left Ventricular Assist Devices

BACKGROUND

Patients with left ventricular assist devices presenting for noncardiac surgery are increasingly commonplace; however, little is known about their outcomes. Accordingly, the authors sought to determine the frequency of complications, risk factors, and staffing patterns.

METHODS

The authors performed a retrospective study at their academic tertiary care center, investigating all adult left ventricular assist device patients undergoing noncardiac surgery from 2006 to 2015. The authors described perioperative profiles of noncardiac surgery cases, including patient, left ventricular assist device, surgical case, and anesthetic characteristics, as well as staffing by cardiac/noncardiac anesthesiologists. Through univariate and multivariable analyses, the authors studied acute kidney injury as a primary outcome; secondary outcomes included elevated serum lactate dehydrogenase suggestive of left ventricular assist device thrombosis, intraoperative bleeding complication, and intraoperative hypotension. The authors additionally studied major perioperative complications and mortality.

RESULTS

Two hundred and forty-six patients underwent 702 procedures. Of 607 index cases, 110 (18%) experienced postoperative acute kidney injury, and 16 (2.6%) had elevated lactate dehydrogenase. Of cases with complete blood pressure data, 176 (27%) experienced intraoperative hypotension. Bleeding complications occurred in 45 cases (6.4%). Thirteen (5.3%) patients died within 30 days of surgery. Independent risk factors associated with acute kidney injury included major surgical procedures (adjusted odds ratio, 4.4; 95% CI, 1.1 to 17.3; P = 0.03) and cases prompting invasive arterial line monitoring (adjusted odds ratio, 3.6; 95% CI, 1.3 to 10.3; P = 0.02) or preoperative fresh frozen plasma transfusion (adjusted odds ratio, 1.7; 95% CI, 1.1 to 2.8; P = 0.02).

CONCLUSIONS

Intraoperative hypotension and acute kidney injury were the most common complications in left ventricular assist device patients presenting for noncardiac surgery; perioperative management remains a challenge.

Renal Function and Outcomes With Use of Left Ventricular Assist Device Implantation and Inotropes in End-Stage Heart Failure: A Retrospective Single Center Study

Background

Left ventricular assist device (LVAD) and inotrope therapy serve as a bridge to transplant (BTT) or as destination therapy in patients who are not heart transplant candidates. End-stage heart failure patients often have impaired renal function, and renal outcomes after LVAD therapy versus inotrope therapy have not been evaluated.

Methods

In this study, 169 patients with continuous flow LVAD therapy and 20 patients with continuous intravenous inotrope therapy were analyzed. The two groups were evaluated at baseline and at 3 and 6 months after LVAD or inotrope therapy was started. The incidence of acute kidney injury (AKI), need for renal replacement therapy (RRT), BTT rate, and mortality for 6 months following LVAD or inotrope therapy were studied. Results between the groups were compared using Mann-Whitney U test and Chi-square with continuity correction or Fischer’s exact at the significance level of 0.05.

Results

Mean glomerular filtration rate (GFR) was not statistically different between the two groups, with P = 0.471, 0.429, and 0.847 at baseline, 3 and 6 months, respectively. The incidence of AKI, RRT, and BTT was not statistically different. Mortality was less in the inotrope group (P < 0.001).

Conclusion

Intravenous inotrope therapy in end-stage heart failure patients is non-inferior for mortality, incidence of AKI, need for RRT, and renal function for 6-month follow-up when compared to LVAD therapy. Further studies are needed to compare the effectiveness of inotropes versus LVAD implantation on renal function and outcomes over a longer time period.

Bridge with a left ventricular assist device to a simultaneous heart and kidney transplant: Review of the United Network for Organ Sharing database

BACKGROUND

Left ventricular assist device (LVAD) implantation as a bridge to cardiac transplantation (BTT) is an effective treatment for end-stage heart failure patients. Currently, there is an increasing number of patients with a LVAD who need a heart and kidney transplant (HKT). Little is known of the prognostic outcomes in these patients. This study was undertaken to determine whether an equivalent outcome would be present in HKTs as compared to a non-LVAD primary HKT cohort.

METHODS

We reviewed the United Network for Organ Sharing database from 2004 to 2013. Orthotropic heart transplant recipients (n = 49 799) were subcategorized as dual organ HKT (n = 1 921) and then divided into cohorts of HKT following continuous flow left ventricular assist device placement (CF-VAD-HKT, n = 113) or no LVAD placement (HKT, n = 1 808). Survival after transplantation was analyzed.

RESULTS

For CF-LVAD-HKT and HKT cohorts, preoperative characteristics were similar regarding age (50.8 ± 13.7, 50.1 ± 13.7, p = 0.75) and panel reactive antibody (12.3 ± 18.4 vs 7.1 ± 18.4, p = 0.06). Donors were similar in age, gender, creatinine, and ejection fraction. Post-transplant, there was no difference in complications. Survival for CF-LVAD-HKT and HKT were similar at 1 year (77% vs 82%) and 3 years (75% vs 77%, log rank p = 0.2814).

CONCLUSIONS

For patients with advanced heart failure and persistent renal dysfunction, simultaneous HKT is a safe option. Survival after CF-LVAD-HKT is equivalent to conventional HKT.

Renal dysfunction and chronic mechanical circulatory support: from patient selection to long-term management and prognosis

PURPOSE OF REVIEW

The purpose of this review is to describe the effects of mechanical circulatory support (MCS) on changes in kidney function and their relationship with mortality, with an additional focus on the evaluation and management of both preimplant and post-MCS renal dysfunction.

RECENT FINDINGS

Renal dysfunction is highly prevalent in patients referred for MCS and is associated with significantly increased mortality and postoperative acute kidney injury. Most patients, including those with renal dysfunction, experience marked early improvement in renal function with MCS, likely secondary to correction of the cardiogenic shock, volume overload, and neurohormonal activation characteristic of advanced heart failure. Currently, there are no diagnostic tests to definitively distinguish reversible forms of renal dysfunction likely to improve with MCS from irreversible renal dysfunction. Furthermore, the characteristic improvements in renal function observed in the early months of MCS are often transient, with subsequent recurrence of renal dysfunction with longer durations of support. Venous congestion, right ventricular dysfunction, and reduced pulsatility are potential mechanisms involved in resurgence of renal dysfunction following MCS.

SUMMARY

With the exponential growth of MCS, research endeavors to both improve understanding of the mechanisms behind observed changes in renal function and elucidate the device-related effects on the kidney are imperative.

Benefits of Intraaortic Balloon Support for Myocardial Infarction Patients in Severe Cardiogenic Shock Undergoing Coronary Revascularization

Background

Prior studies have suggested intraaortic balloon pump (IABP) have a neutral effect on acute myocardial infarction (AMI) patients with cardiogenic shock (CS). However, the effects of IABP on patients with severe CS remain unclear. We therefore investigated the benefits of IABP in AMI patients with severe CS undergoing coronary revascularization.

Methods and Results

This study identified 14,088 adult patients with AMI and severe CS undergoing coronary revascularization from Taiwan’s National Health Insurance Research Database between January 1, 1997 and December 31, 2011, dividing them into the IABP group (n = 7044) and the Nonusers group (n = 7044) after propensity score matching to equalize confounding variables. The primary outcomes included myocardial infarction(MI), cerebrovascular accidents or cardiovascular death. In-hospital events including dialysis, stroke, pneumonia and sepsis were secondary outcomes. Primary outcomes were worse in the IABP group than in the Nonusers group in 1 month (Hazard ratio (HR) = 1.97, 95% confidence interval (CI) = 1.84–2.12). The MI rate was higher in the IABP group (HR = 1.44, 95% CI = 1.16–1.79), and the cardiovascular death was much higher in the IABP group (HR = 2.07, 95% CI = 1.92–2.23). The IABP users had lower incidence of dialysis (8.5% and 9.5%, P = 0.04), stroke (2.6% and 3.8%, P<0.001), pneumonia (13.9% and 16.5%, P<0.001) and sepsis (13.2% and 16%, P<0.001) during hospitalization than Nonusers.

Conclusion

The use of IABP in patients with myocardial infarction and severe cardiogenic shock undergoing coronary revascularization did not improve the outcomes of recurrent myocardial infarction and cardiovascular death. However, it did reduce the incidence of dialysis, stroke, pneumonia and sepsis during hospitalization.