Outcome of patients with ventricular assist devices and acute renal failure requiring renal replacement therapy

A Novel Predictive Model for Hospital Survival in Patients who are Critically Ill with Dialysis-Dependent AKI: A Retrospective Single-Center Exploratory Study

BACKGROUND

Mortality of patients who are critically ill with AKI initiated on RRT is very high. Identifying modifiable and unmodifiable clinical variables at dialysis start that are associated with hospital survival can help, not only in prognostication, but also in clinical triaging.

METHODS

A retrospective observational study was conducted on patients with AKI-D who were initiated on RRT in the medical and surgical intensive care units (ICUs) of a high-acuity academic medical center from January 2010 through December 2015. We excluded patients with suspected poisoning, ESKD, stage 5 CKD not on dialysis, or patients with AKI-D initiated on RRT outside of the ICU setting. The primary outcome was in-hospital mortality.

RESULTS

Of the 416 patients who were critically ill with AKI-D admitted to the medical (38%), surgical (41%), and cardiac (21%) ICUs, with nearly 75% on artificial organ support, the mean age 62.1±14.8 years, mean SOFA score was 11.8±4.3, dialysis was initiated using continuous RRT in 261 (63%) and intermittent hemodialysis in 155 (37%) patients. Incidence of survival to hospital discharge was 48%. Using multivariable logistic regression with stepwise backward elimination, a prognostic model was created that included the variables age, CKD, COPD, admission, and within 24 hours of the start SOFA score, refractory hyperkalemia and uremic encephalopathy as dialysis indications, BUN >100 mg/dl, serum creatinine, serum lactate, serum albumin, CRRT as initial modality, severe volume overload, and abdominal surgery. The model exhibited good calibration (goodness of fit test, P=0.83) and excellent discrimination (optimism-corrected C statistic 0.93).

CONCLUSIONS

In this single-center, diverse, critically ill AKI-D population, a novel prognostic model that combined widely used ICU scores, clinical and biochemical data at dialysis start, and dialysis indication and modality, robustly predicted short-term survival. External validation is needed to prove the generalizability of the study findings.

Risk factors of renal replacement therapy after heart transplantation: a retrospective single-center study

BACKGROUND

Acute kidney injury (AKI) and renal replacement therapy (RRT) are common after heart transplantation (HT). The need for RRT has been reported to be one of the most important predictors of a poor prognosis after HT. Therefore, it is important to early identify risk factors of RRT after HT. However, in the heart transplantation setting, the risk factors are less well studied, and some of the conclusions are controversial. This study aimed to identify the clinical predictors of RRT after HT.

METHODS

This single-center, retrospective study from January 2010 to June 2021 analyzed risk factors (pre-, intra-, and postoperative characteristics) of 163 patients who underwent HT. The endpoint of the study was RRT within 7 days of HT. Risk factors were analyzed by multivariable logistic regression models.

RESULTS

Fifty-five (33.74%) recipients required RRT within 7 days of HT. Factors independently associated with RRT after HT were as follows: a baseline estimated glomerular filtration rate (eGFR) <60 mL/min per 1.73 m² [odds ratio (OR) =3.123; 95% confidence interval (CI): 1.183-8.244; P=0.022], a dose of intraoperative methylprednisolone >10 mg/kg (OR =3.197; 95% CI: 1.290-7.923; P=0.012), the use of mechanical circulatory support (MCS) during surgery (OR =4.903; 95% CI: 1.628-14.766; P=0.005), a cardiopulmonary bypass (CPB) time ≥5 hours (OR =3.929; 95% CI: 1.222-12.634; P=0.022), and postoperative serum total bilirubin (TBIL) ≥60 umol/L (OR =5.105; 95% CI: 1.868-13.952; P=0.001). Protective factors were higher postoperative serum albumin (OR =0.907; 95% CI: 0.837-0.983; P=0.017) and higher postoperative left ventricular ejection fraction (LVEF) (OR =0.908; 95% CI: 0.838-0.985; P=0.020).

CONCLUSIONS

A low preoperative eGFR, a high intraoperative dose of methylprednisolone, a long CPB time, the use of mechanical circulatory support, and a high postoperative TBIL were risk factors for RRT after HT. While a high postoperative serum albumin level and a high left ventricular ejection fraction were protective factors. Understanding these risk factors may help us identify high-risk patients and intervene early.

Heart, kidney and left ventricular assist device: a complex trio

BACKGROUND

Heart failure (HF) is a complex syndrome affecting the whole body, kidneys included. The left ventricular assist device (LVAD) is a valid option for patients with very severe HF. Focusing on renal function, LVAD implantation could theoretically reverse the detrimental effects of HF syndrome on kidneys. However, implanting an LVAD is a high-risk surgical procedure, and LVAD patients have higher risk of bleeding, device thrombosis, strokes, renal impairment, multi-organ failure and infections. Furthermore, an LVAD has its own particular effects on the renal system.

METHODS

In this review, we provide a comprehensive overview of the complex interaction between LVAD and the kidneys from the pathophysiological and clinical perspectives. An analysis of the different effects of pulsatile-flow and continuous-flow LVAD is provided.

RESULTS

Despite their limitations, creatinine-based estimated glomerular filtration rate (eGFR) formulas help to stratify patients by their post-LVAD placement prognosis. Poor basal renal function, the onset of acute kidney injury or the need for renal replacement therapy after LVAD implantation negatively influences a patient's prognosis. LVAD can also prompt an improvement in renal function, however, with some counterintuitive effects on a patient's prognosis.

CONCLUSION

It is still hard to say whether different trends in eGFR depend on different renal conditions before LVAD placement, on a patient's better overall status or on a particular patient management strategy before and/or after the device's implantation. Steps should be taken to solve this question because finding the best candidates for LVAD implantation is of paramount importance to ensure the best outcomes.

Recovery after acute kidney injury requiring kidney replacement therapy in patients with left ventricular assist device: A meta-analysis

BACKGROUND

Acute kidney injury (AKI) is a common and severe complication after left ventricular assist device (LVAD) implantation with an incidence of 37%; 13% of which require kidney replacement therapy (KRT). Severe AKI requiring KRT (AKI-KRT) in LVAD patients is associated with high short and long-term mortality compared with AKI without KRT. While kidney function recovery is associated with better outcomes, its incidence is unclear among LVAD patients with severe AKI requiring KRT.

AIM

To identify studies evaluating the recovery rates from severe AKI-KRT after LVAD placement, which is defined by regained kidney function resulting in the discontinuation of KRT. Random-effects and generic inverse variance method of DerSimonian-Laird were used to combine the effect estimates obtained from individual studies.

METHODS

A total of 268 patients from 14 cohort studies that reported severe AKI-KRT after LVAD were included. Follow-up time ranged anywhere from two weeks of LVAD implantation to 12 mo. Kidney recovery occurred in 78% of enrollees at the time of hospital discharge or within 30 d. Overall, the pooled estimated AKI recovery rate among patients with severe AKI-KRT was 50.5% (95%CI: 34.0%-67.0%) at 12 mo follow up. Majority (85%) of patients used continuous-flow LVAD. While the data on pulsatile-flow LVAD was limited, subgroup analysis of continuous-flow LVAD demonstrated that pooled estimated AKI recovery rate among patients with severe AKI-KRT was 52.1% (95%CI: 36.8%-67.0%). Meta-regression analysis did not show a significant association between study year and AKI recovery rate (P = 0.08). There was no publication bias as assessed by the funnel plot and Egger's regression asymmetry test in all analyses.

RESULTS

A total of 268 patients from 14 cohort studies that reported severe AKI-KRT after LVAD were included. Follow-up time ranged anywhere from two weeks of LVAD implantation to 12 mo. Kidney recovery occurred in 78% of enrollees at the time of hospital discharge or within 30 d. Overall, the pooled estimated AKI recovery rate among patients with severe AKI-KRT was 50.5% (95%CI: 34.0%-67.0%) at 12 mo follow up. Majority (85%) of patients used continuous-flow LVAD. While the data on pulsatile-flow LVAD was limited, subgroup analysis of continuous-flow LVAD demonstrated that pooled estimated AKI recovery rate among patients with severe AKI-KRT was 52.1% (95%CI: 36.8%-67.0%). Meta-regression analysis did not show a significant association between study year and AKI recovery rate (P = 0.08). There was no publication bias as assessed by the funnel plot and Egger's regression asymmetry test in all analyses.

CONCLUSION

Recovery from severe AKI-KRT after LVAD occurs approximately 50.5%, and it has not significantly changed over the years despite advances in medicine.

Incidence and impact of acute kidney injury on patients with implantable left ventricular assist devices: a Meta-analysis

Background: We aimed to evaluate the acute kidney injury (AKI) incidence and its associated risk of mortality in patients with implantable left ventricular assist devices (LVAD).Methods: A systematic literature search in Ovid MEDLINE, EMBASE, and Cochrane Databases was conducted through January 2020 to identify studies that provided data on the AKI incidence and AKI-associated mortality risk in adult patients with implantable LVADs. Pooled effect estimates were examined using random-effects, generic inverse variance method of DerSimonian-Laird.Results: Fifty-six cohort studies with 63,663 LVAD patients were enrolled in this meta-analysis. The pooled incidence of reported AKI was 24.9% (95%CI: 20.1%-30.4%) but rose to 36.9% (95%CI: 31.1%-43.1%) when applying the standard definition of AKI per RIFLE, AKIN, and KDIGO criteria. The pooled incidence of severe AKI requiring renal replacement therapy (RRT) was 12.6% (95%CI: 10.5%-15.0%). AKI incidence did not differ significantly between types of LVAD (p = .35) or indication for LVAD use (p = .62). While meta-regression analysis did not demonstrate a significant association between study year and overall AKI incidence (p = .55), the study year was negatively correlated with the incidence of severe AKI requiring RRT (slope = -0.068, p < .001). The pooled odds ratios (ORs) of mortality at 30 days and one year in AKI patients were 3.66 (95% CI, 2.00-6.70) and 2.22 (95% CI, 1.62-3.04), respectively. The pooled ORs of mortality at 30 days and one year in severe AKI patients requiring RRT were 7.52 (95% CI, 4.58-12.33) and 5.41 (95% CI, 3.63-8.06), respectively.Conclusion: We found that more than one-third of LVAD patients develop AKI based on standard definitions, and 13% develop severe AKI requiring RRT. There has been a potential improvement in the incidence of severe AKI requiring RRT for LVAD patients. AKI in LVAD patients was associated with increased 30-day and 1 year mortality.

Considerations for Long-Term Dialysis Access in Patients with Left Ventricular Assist Devices

BACKGROUND

Renal dysfunction, requiring renal replacement therapy (RRT) is commonly encountered in patients with left ventricular assist devices (LVADs). Continuous flow LVAD (CFLVAD) is the most widely used device. Nonpulsatile blood flow begets special hemodynamic changes. This poses a unique challenge in choosing a long-term dialysis access for patients with CFLVAD where life expectancy is limited.

METHODS

A 61-year-old man with an implanted CFLVAD and renal dysfunction receiving intermittent RRT through a nontunneled dialysis catheter had progressed to dialysis-dependent renal failure. He was referred to us for a permanent hemodialysis access.

RESULTS

The patient underwent a right brachio-brachial arterio-venous graft (AVG) placement. The graft was successfully cannulated for hemodialysis on postoperative day 15. On regular follow-up at 18 months, the graft was still functional.

CONCLUSIONS

Dialysis access for patients on LVAD is an exceptional management problem owing to both altered physiology and guarded overall prognosis. We recommend the use of AVG as a convenient and durable option-facilitating early cannulation and expediting freedom from indwelling catheters that may lead to catastrophic consequences. This should limit the need for secondary interventions, hospitalization, and cost, thus improving quality of life.

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.

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.

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.

Outcomes Associated With Left Ventricular Assist Devices Among Recipients With and Without End-stage Renal Disease

IMPORTANCE

Left ventricular assist devices (LVADs) are widely used both as a bridge to heart transplant and as destination therapy in advanced heart failure. Although heart failure is common in patients with end-stage renal disease (ESRD), little is known about outcomes after LVAD implantation in this population.

OBJECTIVE

To determine the utilization of and outcomes associated with LVADs in nationally representative cohorts of patients with and without ESRD.

DESIGN, SETTING AND PARTICIPANTS

We described LVAD utilization and outcomes among Medicare beneficiaries after ESRD onset (defined as having received maintenance dialysis or a kidney transplant) from 2003 to 2013 based on Medicare claims linked to data from the United States Renal Data System (USRDS), a national registry for ESRD. We compared Medicare beneficiaries with ESRD to a 5% sample of Medicare beneficiaries without ESRD.

EXPOSURES

ESRD (vs no ESRD) among patients who underwent LVAD placement.

MAIN OUTCOMES AND MEASURES

The primary outcome was survival after LVAD placement.

RESULTS

Among the patients with ESRD, the mean age was 58.4 (12.1) years and 62.0% (96) were male. Among those without ESRD, the mean age was 62.2 (12.6) years and 75.1% (196) were male. From 2003 to 2013, 155 Medicare beneficiaries with ESRD (median and interquartile range [IQR] days from ESRD onset to LVAD placement were 1655 days [453-3050 days]) and 261 beneficiaries without ESRD in the Medicare 5% sample received an LVAD. During a median follow-up of 762 days (IQR, 92-3850 days), 127 patients (81.9%) with and 95 (36.4%) without ESRD died. more than half of patients with ESRD (80 [51.6%]) compared with 11 (4%) of those without ESRD died during the index hospitalization. The median time to death was 16 days (IQR 2-447 days) for patients with ESRD compared with 2125 days (IQR, 565-3850 days) for those without ESRD. With adjustment for demographics, comorbidity and time period, patients with ESRD had a markedly increased adjusted risk of death (hazard ratio, 36.3; 95% CI, 15.6-84.5), especially in the first 60 days after LVAD placement.

CONCLUSIONS AND RELEVANCE

Patients with ESRD at the time of LVAD placement had an extremely poor prognosis, with most surviving for less than 3 weeks. This information may be crucial in supporting shared decision-making around treatments for advanced heart failure for patients with ESRD.

Incidence of Acute Renal Failure Associated with Milrinone

Background:

Milrinone is a phosphodiesterase type III inhibitor with positive inotropic and vasodilatory effects used in patients with severe congestive heart failure (CHF).

Objectives:

To determine the incidence rate of acute renal failure (ARF) associated with milrinone therapy.

Methods:

Medical records of 116 patients with cardiomyopathy/severe CHF who received milrinone were reviewed from January 1993 to January 1996. Twenty-nine patients were excluded, resulting in 87 patients, 4 of whom received milrinone twice.

Results:

During a 3-year period, 11 of 91 milrinone therapies became complicated with ARF (incidence 12%). The patients' age (mean ± SD) was 52.3 ± 13.6 years, baseline serum creatinine (SCr) was 1.6 ± 1.0 mg/dL, milrinone dose was 0.47 ± 0.16 μg/kg/min, and mean duration of therapy was 6.5 ± 10.6 days. Fourteen treatments were <24 hours, 2 (14%) of which were complicated with ARF; of the remaining 77 treatments (≥24 h), 9 (11.7%) were complicated with ARF. Their peak SCr was 3.2 ± 1.5 mg/dL and time to peak SCr was 4.9 ± 2.8 days. There was no significant difference in the incidence of ARF in patients who received therapy for <24 hours versus ≥24 hours; in the prevalence rate of diabetes mellitus, hypertension, coronary artery disease; or in baseline SCr, milrinone dose, and duration of therapy between patients who did and did not develop ARF.

Conclusions:

We found a 12% incidence of ARF in patients receiving milrinone therapy for severe CHF, which in the absence of an appropriate control group could be the aggregate effects of milrinone therapy and severe CHF.

Left ventricular assist devices: a kidney's perspective

The left ventricular assist device (LVAD) has become an established treatment option for patients with refractory heart failure. Many of these patients experience chronic kidney disease (CKD) due to chronic cardiorenal syndrome type II, which is often alleviated quickly following LVAD implantation. Nevertheless, reversibility of CKD remains difficult to predict. Interestingly, initial recovery of GFR appears to be transient, being followed by gradual but significant late decline. Nevertheless, GFR often remains elevated compared to preimplant status. Larger GFR increases are followed by a proportionally larger late decline. Several explanations for this gradual decline in renal function after LVAD therapy have been proposed, yet a definitive answer remains elusive. Mortality predictors of LVAD implantation are the occurrence of either postimplantation acute kidney injury (AKI) or preimplant CKD. However, patient outcomes continue to improve as LVAD therapy becomes more widespread, and adverse events including AKI appear to decline. In light of a growing destination therapy population, it is important to understand the cumulative effects of long-term LVAD support on kidney function. Additional research and passage of time are required to further unravel the intricate relationships between the LVAD and the kidney.

Cardiac Assist Devices and Hemodialysis Catheter Procedures - What Do the Nephrologists Need to Know?

The use of ventricular assist devices (VAD) and total artificial heart (TAH) is increasing rapidly, and a large proportion of these device recipients already have or will develop severe renal dysfunction at the time of device implantation. As a consequence, nephrologists are becoming more and more involved in the care of this challenging population. As nephrologists take upon themselves many aspects of dialysis vascular access care, they need to be familiar with the special circumstances of performing hemodialysis catheter procedures in these patients. This review describes the important characteristics of these devices that have serious implications for the technique of placing or replacing dialysis catheters. These implications apply for both tunneled and nontunneled dialysis catheters and so concern all nephrologists, not only the interventionalists. We describe the important anatomical factors, anticoagulation management, device management, vascular access management and technical considerations of placing or replacing tunneled and nontunneled hemodialysis catheters from the perspective of a nephrologist establishing and maintaining lifesaving dialysis vascular access. Without a good understanding of these devices, serious consequences such as VAD rotor damage or blockage, or artificial heart valve blockage or damage can occur. These artificial devices are lifesaving, and any such complication is unacceptable. This review describes steps to minimize the risks.

Combined heart-kidney transplantation after total artificial heart insertion

We present the first single-center report of 2 consecutive cases of combined heart and kidney transplantation after insertion of a total artificial heart (TAH). Both patients had advanced heart failure and developed dialysis-dependent renal failure after implantation of the TAH. The 2 patients underwent successful heart and kidney transplantation, with restoration of normal heart and kidney function. On the basis of this limited experience, we consider TAH a safe and feasible option for bridging carefully selected patients with heart and kidney failure to combined heart and kidney transplantation. Recent FDA approval of the Freedom driver may allow outpatient management at substantial cost savings. The TAH, by virtue of its capability of providing pulsatile flow at 6 to 10 L/min, may be the mechanical circulatory support device most likely to recover patients with marginal renal function and advanced heart failure.

Implantable left ventricular assist devices and the kidney

The use of left ventricular assist devices (LVADs) in treating patients with advanced heart failure restores cardiac output resulting in improved perfusion to multiple organ systems with important clinical benefits. Renal pathophysiology during LVAD support remains an evolving, poorly understood, and potentially dynamic problem. Changes in renal function after LVAD placement have been investigated in multiple studies with contradictory results. Renal dysfunction is common prior to LVAD placement, which complicates postoperative clinical outcomes. The purpose of this review is to assess the latest information regarding the effects of LVADs on renal function with regard to hemodynamics, physiology, pathology and clinical issues prior to and after placement of the devices. The review should then aid in identifying patients best suited to benefit from this technology and to refine the therapy to reduce associated risks.

The effect of continuous blood purification on the prognosis of cardiorenal syndrome patients

To discuss the effect of continuous blood purification (CBP) on the prognosis of cardiorenal syndrome (CRS) patients. Twenty-seven patients were selected for this study, who had previously been treated at the Blood Purification Center of the General Hospital of Jinan Military Region from May 2007 to October 2010. All patients suffered from chronic heart failure and acute kidney injury. Using a non-invasive hemodynamics monitoring system, we observed the dynamic changes in their cardiac output (CO), systemic vascular resistance (SVR), thoracic fluid capacity (TFC), central venous pressure (CVP), urinary volume, and Acute Physiology and Chronic Health Evaluation II system (APACHEII) score. Individual measurements were obtained at 24 h, 48 h, 72 h, 96 h, and 120 h after CBP treatment. At the same time, levels of serum creatinine (Scr), cysteine proteinase inhibitor Cystatin C (CysC), high sensitivity C-reactive protein (hs-CRP), and serum sodium were observed. The fatality rate at 28 days was also recorded. After 24 h of CBP treatment, acidosis, CO, and disturbances in water and electrolyte levels were all improved. As well, concentrations of Scr and CysC were significantly decreased, and the levels of SVR, TFC, and CVP were also decreased. After 72 h of CBP treatment, hs-CRP levels and APACHE II scores were significantly lower (P < 0.01). From 72 to 120 h of CBP treatment, oliguria was resolved in 24 patients, with improved sensitivity to diuretics. The fatality rate at 28 days was 11.12 %. CBP treatment could improve myocardial function, shorten the oliguria period, decrease the fatality rate, and improve the prognosis of CRS patients.

Perioperative plasma neutrophil gelatinase-associated lipocalin measurement in patients who undergo left ventricular assist device implantation surgery

BACKGROUND

Perioperative complication of end-organ injury including acute kidney injury (AKI) is a frequent and severe problem for patients undergoing left ventricular assist device (LVAD) implantation. This study evaluated an emerging AKI biomarker, plasma neutrophil gelatinase-associated lipocalin (NGAL), in a LVAD implantation cohort.

METHODS AND RESULTS

Of 31 LVAD implantation patients enrolled to this study, 17 (55%) patients were diagnosed as having AKI. Six AKI patients showed severe AKI requiring renal replacement therapy (RRT). Plasma NGAL values in the AKI-with-RRT group (n=6) were significantly higher than that in other patients, although the AKI-without-RRT (n=11) group showed a similar level of plasma NGAL to that of the non-AKI group (n=14). Multiple logistic regression analysis revealed that plasma NGAL measured at pre-operation and central venous pressure at pre-operation and 12 h after surgery independently discriminated against postoperative RRT requirement. In the AKI-with-RRT group, plasma NGAL decreased before termination of RRT in 4 patients who eventually showed renal recovery, although no decline of plasma NGAL was observed in 2 patients who showed no recovery of renal function. Removal of blood NGAL by continuous hemodiafiltration was shown to be 70-75% lower than that of creatinine.

CONCLUSIONS

Measurement of perioperative plasma NGAL is useful for predicting severe AKI requiring RRT and renal recovery in patients who have had LVAD implantation surgery. Further investigation is necessary to confirm these findings because this study examined a low number of patients.

Acute kidney injury and mortality following ventricular assist device implantation

BACKGROUND

Ventricular assist devices (VADs) are increasingly common, and their surgical implantation predisposes patients to an increased risk of acute kidney injury (AKI). We sought to evaluate the incidence, risk factors and short- and long-term all-cause mortality of patients with AKI following VAD implantation.

METHODS

We identified all patients who underwent VAD implantation at the University of Chicago between January 1, 2008, and January 31, 2012. We evaluated the incidence of AKI, defined as a ≥50% increase in serum creatinine over the first 7 postoperative days (RIFLE Risk-Creatinine). A logistic regression model was used to identify risk factors for the development of AKI, and a Cox proportional hazards model was used to examine factors associated with 30-day and 365-day all-cause mortality.

RESULTS

A total of 157 eligible patients had VAD implantations with 44 (28%) developing postimplantation AKI. In a multivariate analysis, only diabetes mellitus [odds ratio = 2.25 (1.03-4.94), p = 0.04] was identified as a significant predictor of postoperative AKI. Using a multivariable model censored for heart transplantation, only AKI [hazard ratio, HR = 3.01 (1.15-7.92), p = 0.03] and cardiopulmonary bypass time [HR = 1.01 (1.001-1.02), p = 0.02] were independent predictors of 30-day mortality. Preoperative body mass index [HR = 0.95 (0.90-0.99), p = 0.03], preoperative diabetes mellitus [HR = 1.89 (1.07-3.35), p = 0.03] and postimplantation AKI [HR = 1.85 (1.06-3.21), p = 0.03] independently predicted 365-day mortality.

CONCLUSION

AKI is common following VAD implantation and is an independent predictor of 30-day and 1-year all-cause mortality.

Significance of postoperative acute renal failure after continuous-flow left ventricular assist device implantation

BACKGROUND

Deteriorating renal function is common in patients with advanced heart failure and is associated with poor outcomes. The relationship between renal function and left ventricular assist device (LVAD) implantation is complex and has been explored in multiple studies with contradictory results. The aim of our study is to examine the significance of postoperative renal failure after implantation of a continuous-flow LVAD and its relationship to outcomes.

METHODS

From March 2006 to July 2011, 100 patients underwent implantation of a HeartMate II (Thoratec Corp, Pleasanton, CA) or HeartWare (Heart International, Inc, Framingham, MA) LVAD at our institution. Patients were stratified based on postoperative development of acute renal failure (ARF). Variables were compared using 2-sided t tests, χ(2) tests, Cox proportional hazards models, and log-rank tests to determine whether there was a difference between the 2 groups and whether postoperative renal failure was a significant independent predictor of outcome.

RESULTS

We identified 28 patients (28%) with postoperative ARF and 72 patients (72%) without postoperative ARF. The 2 groups were similar with regard to demographics and comorbidities. The patients with ARF were more likely to be intubated preoperatively (14.3% versus 1.4%; p = 0.021) and had higher preoperative central venous pressure (CVP) (14.3 mm Hg versus 10.7 mm Hg; p = 0.015). Postoperatively patients with ARF had a longer hospital stay (32.4 versus 18.7; p = 0.05), were more likely to experience right ventricular (RV) failure (25% versus 5.6%; p = 0.01) and ventilator-dependent respiratory failure (VDRF) (28.6% versus 6.9%; p = 0.007). There was a significant difference when comparing the ARF and non-ARF groups for 30-day (17.9% versus 0%; p < 0.001), 180-day (28.6% versus 2.8%; p < 0.001), and 360-day mortality (28.6% versus 6.9%; p = 0.012).

CONCLUSIONS

Patients in whom ARF developed after LVAD implantation had a higher rate of VDRF and RV failure and a longer length of stay (LOS). Postoperative ARF was associated with higher mortality at the 30-day, 180-day, and 360-day intervals. ARF after LVAD may be an early marker of poor outcome, particularly RV failure, and may be an opportunity for early intervention and rescue.

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

OBJECTIVES

The aim of this study was to determine renal outcomes after left ventricular assist device (LVAD) implantation.

BACKGROUND

Renal dysfunction before LVAD placement is frequent, and it is unclear whether it is due to primary renal disease or to poor perfusion.

METHODS

A retrospective single-center analysis was conducted in 83 consecutive patients implanted with HeartMate II continuous-flow LVADs (Thoratec Corp., Pleasanton, California). Calculated glomerular filtration rate (GFR) was assessed on admission and 1, 3, and 6 months after implantation. To define predictors for improvement in GFR, clinical variables were examined in patients with decreased renal function (GFR <60 ml/min/1.73 m(2)) before LVAD, surviving and dialysis-free at 1 month (n = 44).

RESULTS

GFR significantly increased from admission (53.2 ± 21.4 ml/min/1.73 m(2)) to 1 month after LVAD implantation (87.4 ± 27.9 ml/min/1.73 m(2)) (p < 0.0001). Subsequently, at 3 and 6 months, GFR remained significantly (p < 0.0001) above pre-LVAD values. Of the 51 patients with GFRs <60 ml/min/1.73 m(2) before LVAD surviving at 1 month, 34 (67%) improved to GFRs >60 ml/min/1.73 m(2). Univariate pre-operative predictors for improvement in renal function at 1 month included younger age (p = 0.049), GFR improvement with optimal medical therapy (p < 0.001), intra-aortic balloon pump use (p = 0.004), kidney length above 10 cm (p = 0.023), no treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (p = 0.029), higher bilirubin (p = 0.002), higher Lietz-Miller score (p = 0.019), and atrial fibrillation (p = 0.007). Multivariate analysis indicated pre-operative improved GFR (slope = 0.5 U per unit improved; 95% confidence interval: 0.2 to 0.8; p = 0.003), atrial fibrillation (slope = 27; 95% confidence interval: 8 to 46; p = 0.006), and intra-aortic balloon pump use (slope = 14; 95% confidence interval: 2 to 26; p = 0.02) as independent predictors.

CONCLUSIONS

In most patients with end-stage heart failure considered for LVAD implantation, renal dysfunction is reversible and likely related to poor renal perfusion.

Long-term outcome after acute renal replacement therapy: a narrative review

BACKGROUND

Acute kidney injury (AKI) necessitating renal replacement therapy (RRT) is associated with high short-term mortality, relatively little however is known of the long-term outcome in these patients. This narrative review describes renal recovery, long-term mortality, and quality of life in RRT patients with acute kidney injury.

METHODS

A literature search using the PubMed search engine from the year 2000 to present with the MeSH terms 1) acute kidney injury, renal replacement therapy, prognosis, and 2) acute kidney injury, quality of life, prognosis, was performed, including studies addressing long-term outcome (over 60 days) in adults with AKI on RRT.

RESULTS

According to inclusion criteria, twenty two studies were eligible. Outcome varied depending on AKI aetiology, setting, co-morbidity and pre-morbid renal function. Five-year-survival was between 15% and 35%, with dialysis dependence in less than 10% of survivors. Renal recovery, even if incomplete occurred during the first year. Quality of life assessment amongst survivors indicated moderate physical impairment and reduced mental health scores. A majority of patients returned to employment and self-sustainability and reported acceptable to good quality of life. Over 90% of patients indicated that they would undergo the same treatment again.

DISCUSSION AND CONCLUSIONS

Early initiation of treatment and fine-tuning of the RRT technique may improve outcome. Consensus regarding AKI definitions, renal function measurement and standardised follow-up regimens are required. Further long-term studies are needed.

Early adverse events as predictors of 1-year mortality during mechanical circulatory support

BACKGROUND

Ventricular assist devices (VADs) provide effective treatment for end-stage heart failure; however, most patients experience > or =1 major adverse events (AEs) while on VAD support. Although early, non-fatal AEs may increase the risk of later death during VAD support, this relationship has not been established. Therefore, we sought to determine the impact on 1-year mortality of AEs occurring during the first 60 days of VAD support.

METHODS

A retrospective analysis was performed using prospectively collected data from a single-site database for patients aged > or =18 years receiving left ventricular or biventricular support during 1996 to 2008 and who survived >60 days on VAD support. Fourteen major classes of AEs occurring during this 60-day period were examined. One-year survival rates of patients with and without each major AE were compared.

RESULTS

The study included 163 patients (80% men; mean age, 49.5 years), of whom 87% were European American, 72% had left ventricular support, and 83% were bridge to transplant. The occurrence of renal failure, respiratory failure, bleeding events, and reoperations during the first 60 days after implantation significantly increased the risk of 1-year mortality. After controlling for gender, age, VAD type, and intention to treat, renal failure was the only major AE significantly associated with later mortality (hazard ratio, 2.96; p = .023).

CONCLUSIONS

Specific AEs, including renal failure, respiratory and bleeding events, and reoperations, significantly decrease longer-term survival. Renal failure conferred a 3-fold increased risk of 1-year mortality. Peri-operative management should focus on strategies to mitigate risk for renal failure in order to maximize later outcomes.

Renal function and outcome after continuous flow left ventricular assist device implantation

BACKGROUND

Renal dysfunction as a risk factor with the use of left ventricular assist devices (LVAD) is controversial. We determined the effect of renal function on outcomes after continuous flow LVAD implantation.

METHODS

Eighty-six patients with advanced heart failure undergoing continuous flow LVAD implantation as bridge to transplantation from November 1998 to July 2007 were retrospectively analyzed. Renal function was assessed using the Modification of Diet in Renal Disease study-derived glomerular filtration rates (GFR [mL x min(-1) x 1.73 m(-2)]). Patients were categorized into two groups based on pre-LVAD GFR: those with normal renal function (GFR > 60, n = 46), and those with renal dysfunction (GFR < 60, n = 40).

RESULTS

Post-LVAD survival at 1, 3, and 6 months for GFR greater than 60 was 91.3%, 79.9%, 72.6%, respectively, and for GFR less than 60, it was 92.5%, 66.5%, 47.9%, respectively (p = 0.038). Bridge-to-transplant rate was lower for GFR less than 60 than for GFR greater than 60 (40.0% versus 63.0%, p = 0.033). For GFR less than 60, GFR improved on LVAD support: implant to month 6, 41.7 +/- 11.5 to 62.7 +/- 25.0 (p = 0.021). Post-LVAD survival was improved in GFR less than 60 patients who after LVAD implantation recovered renal function to GFR greater than 60 (p < 0.001). Patients with post-LVAD renal failure had significantly lower post-LVAD survival regardless of pre-LVAD renal function (p < 0.001).

CONCLUSIONS

Patients with renal dysfunction have poorer outcomes after continuous flow LVAD implantation. However, renal function improves after LVAD implantation and is associated with improved survival. Our data underscore the importance of end-organ function in patient selection for LVAD therapy.

Long-term risk of mortality and other adverse outcomes after acute kidney injury: a systematic review and meta-analysis

BACKGROUND

Acute kidney injury (AKI) is common in hospitalized patients. The impact of AKI on long-term outcomes is controversial.

STUDY DESIGN

Systematic review and meta-analysis.

SETTING & PARTICIPANTS

Persons with AKI.

SELECTION CRITERIA FOR STUDIES

MEDLINE and EMBASE databases were searched from 1985 through October 2007. Original studies describing outcomes of AKI for patients who survived hospital discharge were included. Studies were excluded from review when participants were followed up for less than 6 months.

PREDICTOR

AKI, defined as acute changes in serum creatinine level or acute need for renal replacement therapy.

OUTCOMES

Chronic kidney disease (CKD), cardiovascular disease, and mortality.

RESULTS

48 studies that contained a total of 47,017 participants were reviewed; 15 studies reported long-term data for patients without AKI. The incidence rate of mortality was 8.9 deaths/100 person-years in survivors of AKI and 4.3 deaths/100 patient-years in survivors without AKI (rate ratio [RR], 2.59; 95% confidence interval, 1.97 to 3.42). AKI was associated independently with mortality risk in 6 of 6 studies that performed multivariate adjustment (adjusted RR, 1.6 to 3.9) and with myocardial infarction in 2 of 2 studies (RR, 2.05; 95% confidence interval, 1.61 to 2.61). The incidence rate of CKD after an episode of AKI was 7.8 events/100 patient-years, and the rate of end-stage renal disease was 4.9 events/100 patient-years.

LIMITATIONS

The relative risk for CKD and end-stage renal disease after AKI was unattainable because of lack of follow-up of appropriate controls without AKI.

CONCLUSIONS

The development of AKI, defined as acute changes in serum creatinine level, characterizes hospitalized patients at increased risk of long-term adverse outcomes.

Fenoldopam for acute kidney injury in children

We report two cases of children with severe cardiomyopathy requiring treatment with ventricular assist devices who developed acute kidney injury and were treated with fenoldopam. Therapy with fenoldopam appeared successful in one case in that renal replacement therapy was avoided with improvement in urine output and renal function. These are the first reported cases of fenoldopam use in children with acute kidney injury receiving mechanical circulatory support.

Incorporation of an In-Line Filter for Ultrafiltration or Hemodialysis to the Abiomed BVS5000 Ventricular Assist Device

Multiple organ system dysfunction is an associated finding in patients requiring acute ventricular assist device (VAD) support. In the setting of acute renal failure, percutaneous catheters are placed for hemodialysis and/or ultrafiltration. Incorporation of an ultrafiltration or hemodialysis system in the Abiomed BVS5000 VAD circuit is a simple maneuver that eliminates the need for an additional catheter, thereby reducing the vascular and infectious complications associated with these catheters. We recommend splicing connectors into the outflow tubing of the right VAD circuit for attachment to an ultrafiltration or hemodialysis unit. This technique is a safe, simple, and reliable method by which to perform intermittent or continuous ultrafiltration or hemodialysis.

Relationship Between Renal Function and Left Ventricular Assist Device Use

BACKGROUND

Poor renal function may affect outcomes after left ventricular assist device (LVAD) placement. Conversely, LVADs may optimize circulation and improve renal function.

METHODS

To assess the relationship between renal function and LVAD use, changes in creatinine clearances (CrCl, in mL/min) were assessed retrospectively in 220 patients who underwent LVAD placement. These patients were also divided into four groups based on CrCl quartiles (< 47, 48-68, 69-95, and > 95) and compared for outcomes post-LVAD placement.

RESULTS

Eighty-four patients died on LVAD support. Survival on LVAD was worse for patients with the worst baseline CrCl (42%, 52%, 63%, and 79% for 6 month and 26%, 34%, 47%, and 66% for 12 month survival for quartiles 1-4; both p < 0.01 for trend). Adjusting for other covariates, patients in the lowest CrCl quartile were at a higher risk of dying postimplant (odds ratio 1.95, 95% confidence interval 1.14-3.63). Paired sample analysis showed the following changes in CrCl: preoperative to week 1, 77.0 +/- 46.6 to 92.1 +/- 51.1 (p < 0.01; n = 202), week 1 to 2, 89.4 +/- 49.2 to 95.2 +/- 52.4 (p = 0.01, n = 171), week 2 to 3, 107.5 +/- 58.1 to 113.7 +/- 66.1 (p = 0.16, n = 74), and week 3 to 4, 111.1 +/- 56.6 to 110.5 +/- 56.8 (p = 0.87, n = 60). For the 60 patients with baseline CrCl less than 50, CrCl increased from 36.7 +/- 9.2 to 60.1 +/- 35.5 (p < 0.01; n = 55 pairs) from preimplant to week 1. In 37 of these patients (62%) on intraaortic balloon pump support preimplant, CrCl increased from 38.4 +/- 8.2 to 67.9 +/- 40.3 mL/minute (p < 0.01) during week 1 postimplant. Recovery of renal function to CrCl greater than 50 was associated with a trend towards better 30-day survival (84% vs 66%, p = 0.09).

CONCLUSIONS

Baseline poor renal function is associated with worse outcomes after LVAD implantation. However, renal function improves substantially and rapidly in post-LVAD survivors and is associated with improved outcomes. These data underscore the importance of careful patient selection for LVAD therapy.

Predictors and Outcomes of Continuous Veno-venous Hemodialysis Use After Implantation of a Left Ventricular Assist Device

BACKGROUND

Post-operative renal failure is a common complication after left ventricular assist device (LVAD) implantation. This study was designed to evaluate predictors and outcomes of acute renal failure after LVAD insertion.

METHODS

Two-hundred one patients undergoing LVAD implantation at a single institution from June 1996 through April 2004 were retrospectively analyzed. Patients were categorized into 2 groups: those who required post-operative continuous veno-venous hemodialysis (CVVHD) (Group 1, n = 65, 32.3%) and those who did not (Group 2, n = 136, 67.7%). Independent predictors of post-operative renal failure requiring CVVHD were determined using multivariate logistic regression techniques.

RESULTS

Patients who had post-operative renal failure requiring CVVHD were older (53.7 +/- 12.9 vs 48.2 +/- 14.2 years, p = 0.009), had a higher incidence of intra-aortic balloon pump use (46.6% vs 26.2%, p = 0.006), and had a higher pre-operative mean LVAD score (5.8 +/- 3.5 vs 3.8 +/- 3.3, p = 0.001) than those without renal failure. LVAD score was the only independent predictor of post-operative renal failure requiring CVVHD (odds ratio = 1.226, p = 0.006). Sepsis rate was higher (33.3% vs 6.9%, p < 0.001) and bridge-to-transplantation rate was lower (52.4% vs 83.5%, p < 0.001) in Group 1 than in Group 2. Post-LVAD survival rates at 1, 3, 5 and 7 years for Group 1 and Group 2 were 43.2%, 39.1%, 34.7% and 34.7% vs 79.2%, 74.0%, 68.3% and 66.4%, respectively (log rank, p < 0.001).

CONCLUSIONS

Acute renal failure necessitating CVVHD remains a serious complication after LVAD and confers significant morbidity and mortality. Pre-operative evaluation of patient risk factors and optimization of peri-operative hemodynamics are of utmost importance to prevent this major complication.

Patient selection for assist devices: bridge to transplant

Patients in severely progressed states of heart failure can be bridged to successful heart transplantation with mechanical assist devices. Experience has demonstrated that patient selection and timing of device implantation are crucial for obtaining acceptable results when using this expensive technology. The degree of irreversible secondary organ dysfunction before re-establishing adequate cardiac output determines the chance of reaching transplantation. Patients who recover during support from all sequelae of end stage heart failure have an excellent outcome after heart transplantation.

Severe renal dysfunction complicating cardiogenic shock is not a contraindication to mechanical support as a bridge to cardiac transplantation

OBJECTIVES

This study investigated outcomes in patients with cardiogenic shock and severe renal dysfunction treated with ventricular assist devices (VAD) as a bridge to cardiac transplantation.

BACKGROUND

Previous reports have documented poor survival in patients with cardiogenic shock and severe renal dysfunction treated with VAD.

METHODS

We surveyed 215 consecutive patients who received a VAD from 1992 to 2000 and selected patients who had a serum creatinine > or =3.0 mg/dl at the time of VAD placement. Demographic, laboratory, and clinical outcome data were collected.

RESULTS

Eighteen patients met the inclusion criteria. Mean serum creatinine at the time of VAD placement was 4.0 +/- 0.7 mg/dl (range 3.0 to 5.2 mg/dl). Seven patients required temporary renal support with continuous venovenous hemodialysis (CVVHD). Eleven patients underwent cardiac transplantation. At six months post-transplantation, mean serum creatinine was 2.0 +/- 0.6 mg/dl (range 1.3 to 3.5 mg/dl). None of the transplanted patients required subsequent renal support. Seven patients died with a VAD before transplantation. Three died early (<1 month) after VAD placement, and all three required CVVHD until death. Four patients survived for >1 month after VAD placement; all four had resolution of renal dysfunction with mean serum creatinine of 1.9 +/- 1.2 mg/dl (range 0.8 to 3.6 mg/dl) without the need for renal support. Overall 30-day and six-month survival after VAD placement, survival to transplantation, and survival one year post-transplantation were similar to patients without severe renal dysfunction.

CONCLUSIONS

Contemporary use of VAD leads to resolution of severe renal dysfunction in most cardiogenic shock patients and comparable long-term outcomes to patients without renal dysfunction.