Prevalence and prognostic importance of changes in renal function after mechanical circulatory support

Abstract

Background: The long-term durability and prognostic significance of improvement in renal function after mechanical circulatory support (MCS) has yet to be characterized in a large multicenter population. The primary goals of this analysis were to describe serial post-MCS changes in estimated glomerular filtration rate (eGFR) and determine their association with all-cause mortality.

Methods and results: Adult patients enrolled in the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) with serial creatinine levels available (n=3363) were studied. Early post-MCS, eGFR improved substantially (median improvement, 48.9%; P<0.001) with 22.3% of the population improving their eGFR by ≥100% within the first few weeks. However, in the majority of patients, this improvement was transient, and by 1 year, eGFR was only 6.7% above the pre-MCS value (P<0.001). This pattern of early improvement followed by deterioration in eGFR was observed with both pulsatile and continuous-flow devices. Interestingly, poor survival was associated with both marked improvement (adjusted hazard ratio [HR], 1.64; 95% confidence interval [CI], 1.19-2.26; P=0.002) and worsening in eGFR (adjusted HR, 1.63; 95% CI, 1.15-2.13; P=0.004).

Conclusions: Post-MCS, early improvement in renal function is common but seems to be largely transient and not necessarily indicative of an improved prognosis. This pattern was observed with both pulsatile and continuous-flow devices. Additional research is necessary to better understand the mechanistic basis for these complex post-MCS changes in renal function and their associated survival disadvantage.

Clinical trial registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00119834.

Keywords: cardio-renal syndrome; heart failure; heart-assist devices; transplantation.

Figure 1

Mean eGFR over time grouped by device strategy, disease severity, and device flow. A, Mean eGFR over time by baseline device strategy or transplant status at end of follow-up. B, Mean eGFR over time by baseline INTERMACS Profile. C, Slope of the lines reflects the rate of change in eGFR over time. Sample sizes (n) refer to the number of patients in each group through 1 month, and sample sizes (N) refer to the number of patients with data available at each of the subsequent time points. eGFR indicates estimated glomerular filtration rate; INTERMACS, Interagency Registry for Mechanically Assisted Circulatory Support; and MCS, mechanical circularity support. Bridge to transplant defined as patients listed for transplantation or those deemed likely by the treating physician to be listed at the time of implantation.

Figure 2

Mean eGFR over time in patients with and without pre-MCS renal dysfunction and post-MCS IRF. Mean eGFR according to presence or absence of baseline renal dysfunction further stratified by IRF at 1 mo post-MCS. Renal dysfunction defined as a pre-MCS eGFR <60 mL/min per 1.73 m². IRF is defined as a ≥50% improvement in eGFR from pre-MCS to 1 mo post-MCS. Sample sizes (N) refer to the number of patients with data available at all time points. eGFR indicates estimated glomerular filtration rate; IRF, improvement in renal function; and MCS, mechanical circulatory support.

Figure 3

Proportion of patients across stages of renal function over time. Sample sizes (N) refer to the number of patients with data available at each time point. eGFR indicates estimated glomerular filtration rate (mL/min per 1.73 m²); and MCS, mechanical circulatory support.

Figure 4

Relationship between early post-MCS changes in renal function and risk of death. Kaplan–Meier survival curves according to percent change in eGFR quintile. Percent change in eGFR is from pre-MCS to 1 mo post-MCS. eGFR indicates estimated glomerular filtration rate; and MCS, mechanical circulatory support.