In the NEWS: LVADs and ESRD

Should patients on dialysis or kidney transplant be offered LVADS for severe CHF?
A new study just published in JAMA internal Medicine showed that patients with ESRD at the time of LVAD placement had an extremely poor prognosis, with most surviving for less than 3 weeks.

This was a observational analysis of the USRDS data of all patients on ESRD that received an LVAD.  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, 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 for patients with ESRD compared with 2125 days for those without ESRD. Most of these patients were hemodialysis with a small minority being PD and transplantation. So, unclear what the data is for PD vs transplantation.

In addition, what would have happened if the patients continued conservative management and not offered LVAD- would their outcomes have been similar or better? This really brings the question on whether LVADS should be offered to ESRD patients on dialysis.

Two recent reviews in AJKD and CJASN discuss the role of the Nephrologist and the Kidney in patients with LVADs.

TOPIC Discussion: LVAD 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 a recent review in CJASN, 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.

Salient points   

Most of the AKI and CKD post LVAD is related to right ventricular failure. Identifying that and providing aggressive diuresis and or UF might be important.
Long term CKD related to LVAD might be related to hemolysis and R-CHF.
Hemodialysis and PD – both can be successfully be done in outpatient setting with LVADs
AVF should be still the first choice for LVAD patients in the outpatient settings that require dialysis e
The most important of all, interdisciplinary teams including cardiologist, surgeons, and nephrologists are critical in the success of an LVAD program.

Topic Discussion: AKI following LVAD

Left ventricular assist devices (LVADs) are used increasingly as a bridge to transplantation or as destination therapy in end-stage heart failure patients who do not respond to optimal medical therapy. Many of these patients have end-organ dysfunction, including advanced kidney dysfunction, before and after LVAD implantation. Kidney dysfunction is a marker of adverse outcomes, such as increased morbidity and mortality.The incidence of AKI after LVAD implantation varies considerably: between 4 and 38 %. 

Risk factors:
INTERMACS score 1 or 2 ( http://content.onlinejacc.org/article.aspx?articleid=1143100)
Kidney <10 cm in size
Older age
ACE-I or ARB therapy immediately prior to surgery
High central venous pressure
Low LV end-diastolic dimensions
Long CPB time
Higher intraop bleeding
Need for re operation
Sepsis
Liver dysfunction
Need for blood transfusions
RV failure
CKD

Factors such as acute blood loss, volume shifts, arrhythmias, and the effect of multiple vasoactive medications influence renal hemodynamics. The sudden change in renal blood flow characteristics due to continuous flow-LVAD support can lead to AKI. Patients with preoperative RV failure and patients with INTERMACS scores of 1 or 2 are at higher risk of AKI.  The RV function is of vital importance after LVAD placement since postoperative RV failure and idioventricular arrhythmias have been associated with AKI . An RV dysfunction can result in a reduced LV preload, low LVAD speeds, reduced forward flow, increased arrhythmias, and liver as well as kidney congestion.

It appears that the cause is hemodynamic vs ATN. No study has really defined the mechanism. Given the LVAD devices have pro thrombotic risk , renal vascular thrombosis and or anticoagulation related AKI should be in the differential. As always, AIN from any medication is to be considered. Hemolysis related injury could be leading to pigment nephropathy as well.

https://www.ncbi.nlm.nih.gov/pubmed/25759700
https://www.ncbi.nlm.nih.gov/pubmed/25796403