Left ventricular assist devices a kidney’s perspe

Authors: T R Tromp N de Jonge J A Joles

Publish Date: 2015/03/22

Volume: 20, Issue: 4, Pages: 519-532

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Abstract

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 longterm LVAD support on kidney function Additional research and passage of time are required to further unravel the intricate relationships between the LVAD and the kidneyApproximately 1–2  of the adult population in developed countries suffers from heart failure HF 1 In the USA an estimated 57 million people suffer from HF 2 whereas worldwide the number of HF patients exceeds 23 million 3 Although most cases can be managed pharmacologically and/or surgically HF may progress and become unresponsive to conventional treatment 4 For these refractory HF patients encompassing an estimated 5–10  of the total HF population 5 heart transplantation HTx is currently the gold standard of treatment 4 6 7 8 However HTx is limited by availability of donor hearts 7 and patients may not always meet criteria for placement on waiting lists 4 Eurotransplant reported an increasing number of patients waiting for HTx a trend unmatched by donor heart availability 9 Consequently waiting list mortality remains too high 10 11Implantable left ventricular assist devices LVAD have revolutionized treatment of latestage systolic HF 7 12 An LVAD is an implantable mechanical circulatory support MCS device powered by an external driveline cable which aids the failing heart by unloading the left or right ventricle In 2001 the pivotal REMATCH trial showed that LVAD therapy was superior to maximal medical therapy 1year survival rate of the LVAD group doubled that of the control group receiving such therapy 52 vs 25  13 Although LVADs were first accepted to support patients awaiting HTx the socalled bridge to transplantation therapy they are now increasingly being offered to patients ineligible for HTx Such destination therapy DT can be seen as an alternative to HTx 14 15 It has to be noted that some patients initially intended for DT may improve sufficiently to become HTx eligible again the bridge to candidacy population This implies that the division between bridge to transplantation therapy and DT is not always entirely black and whiteThe firstgeneration LVAD pumps were large and pneumatically driven creating pulsatileflow pf However these devices showed many adverse events The new generation of continuousflow cf pumps is smaller more durable and shows a considerably improved safety profile 16 Moreover cfLVADs are easier to implant operate silently but create high shear stress and areas of stasis 17 Retrospective analysis of large patient samples has shown that cfLVADs offer superior survival over pfLVADs with fewer adverse events 16 and at lower cost 18 However the nonphysiologic nature of these devices has been topic of debate Since 2010 continuousflow devices accounted for over 99  of LVADs implanted in the USA 16

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