AKI after Transcatheter or Surgical Aortic Valve Replacement

Persistent acute kidney injury following transcatheter aortic valve replacement

BACKGROUND

Acute kidney injury (AKI) and its severity after transcatheter aortic valve replacement (TAVR) have been associated with worse outcomes. Studies have shown that AKI duration (transient or persistent) affects outcomes independently of AKI severity. This study was undertaken to determine the association, risk factors, and outcomes associated with persistent AKI (pAKI) after TAVR.

METHODS

Adult patients undergoing TAVR at Mayo Clinic between January 1, 2008 and June 30, 2014 were enrolled. pAKI was defined as an increased serum creatinine at hospital discharge (≥0.3 mg/dL or ≥50% from baseline). Risk factors associated with pAKI were identified with multivariate logistic regression.

RESULTS

A total of 386 patients met the inclusion criteria. Fifty patients (13%) had pAKI. Independent risk factors for pAKI on multivariate analysis included diabetes mellitus (odds ratio [OR], 2.43; 95% confidence interval [CI], 1.29-4.66), prior percutaneous coronary intervention (PCI) (OR, 2.39; 95%CI, 1.24-4.80), intra-aortic balloon pump (IABP) use (OR, 8.14; 95%CI, 1.60-45.78), and blood transfusion (OR, 2.22; 95%CI, 1.15-4.27). Protective factors for pAKI included a higher baseline estimated glomerular filtration rate (eGFR) (OR, 0.83 per 10-mL/min/1.73 m² increase in eGFR; 95%CI, 0.71-0.99). After adjusting for the Society of Thoracic Surgeons cardiac surgery risk score, pAKI occurrence remained significantly associated with increased 2-year mortality among hospital survivors (hazard ratio, 2.65; 95%CI, 1.51-4.41).

CONCLUSION

pAKI was significantly associated with higher mortality risk following TAVR. Baseline eGFR, diabetes mellitus, previous PCI, IABP, and blood transfusion were risk factors for post-procedural pAKI.

The association between renal recovery after acute kidney injury and long-term mortality after transcatheter aortic valve replacement

Background

This study aimed to examine the association between renal recovery status at hospital discharge after acute kidney injury (AKI) and long-term mortality following transcatheter aortic valve replacement (TAVR).

Methods

We screened all adult patients who survived to hospital discharge after TAVR for aortic stenosis at a quaternary referral medical center from January 1, 2008, through June 30, 2014. An AKI was defined as an increase in serum creatinine level of 0.3 mg/dL or a relative increase of 50% from baseline. Renal outcome at the time of discharge was evaluated by comparing the discharge serum creatinine level to the baseline level. Complete renal recovery was defined as no AKI at discharge, whereas partial renal recovery was defined as AKI without a need for renal replacement therapy at discharge. No renal recovery was defined as a need for renal replacement therapy at discharge.

Results

The study included 374 patients. Ninty-eight (26%) patients developed AKI during hospitalization: 55 (56%) had complete recovery; 39 (40%), partial recovery; and 4 (4%), no recovery. AKI development was significantly associated with increased risk of 2-year mortality (hazard ratio [HR], 2.20 [95% CI, 1.37–3.49]). For patients with AKI, the 2-year mortality rate for complete recovery was 34%; for partial recovery, 43%; and for no recovery, 75%; compared with 20% for patients without AKI (P < .001). In adjusted analysis, complete recovery (HR, 1.87 [95% CI, 1.03–3.23]); partial recovery (HR, 2.65 [95% CI, 1.40–4.71]) and no recovery (HR, 10.95 [95% CI, 2.59–31.49]) after AKI vs no AKI were significantly associated with increased risk of 2-year mortality.

Conclusion

The mortality rate increased for all patients with AKI undergoing TAVR. A reverse correlation existed for progressively higher risk of death and the extent of AKI recovery.

Association of frailty status with acute kidney injury and mortality after transcatheter aortic valve replacement: A systematic review and meta-analysis

Objective

Frailty is a common condition in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR). The aim of this systematic review was to assess the impact of frailty status on acute kidney injury (AKI) and mortality after TAVR.

Methods

A systematic literature search was conducted using MEDLINE, EMBASE, and Cochrane databases from the inception through November 2016. The protocol for this study is registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42016052350). Studies that reported odds ratios, relative risks or hazard ratios comparing the risk of AKI after TAVR in frail vs. non-frail patients were included. Mortality risk was evaluated among the studies that reported AKI-related outcomes. Pooled risk ratios (RR) and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method.

Results

Eight cohort studies with a total of 10,498 patients were identified and included in the meta-analysis. The pooled RR of AKI after TAVR among the frail patients was 1.19 (95% CI 0.97–1.46, I² = 0), compared with non-frail patients. When the meta-analysis was restricted only to studies with standardized AKI diagnosis according to Valve Academic Research Consortium (VARC)-2 criteria, the pooled RRs of AKI in frail patients was 1.16 (95% CI 0.91–1.47, I² = 0). Within the selected studies, frailty status was significantly associated with increased mortality (RR 2.01; 95% CI 1.44–2.80, I² = 58).

Conclusion

The findings from our study suggest no significant association between frailty status and AKI after TAVR. However, frailty status is associated with mortality after TAVR and may aid appropriate patient selection for TAVR.

Role of β2-microglobulin in postoperative cognitive decline

Aim: β2-microglobulin (β2M) was proved to affect hippocampal functions in mice. Materials & methods: Seventy-one patients undergoing aortic valve replacement were analyzed in prospective observational study. Kidney biomarkers and Mini Mental State Examinations (MMSEs) were performed before procedure, at discharge and after 6 months. Results: Patients with β2M increase over the median change (>0.42 mg/l) experienced a significant in-hospital drop in MMSE (p = 0.005). Patients with β2M increase over the median change also failed to improve a delayed-word-recall domain of the test (p = 0.826) while patients with a lower increase improved results in the domain (p = 0.004). After 6 months, MMSE improvement was associated with a significant decrease in β2M (p = 0.042). Conclusion: These are the first in man data demonstrating relation between changes in cognition and β2M. The phenomenon was reversible which indicates its therapeutic potential.

Direct and adjusted indirect comparisons of perioperative mortality after sutureless or rapid-deployment aortic valve replacement versus transcatheter aortic valve implantation

OBJECTIVES

To determine which procedure, aortic valve replacement (AVR) with a sutureless or rapid-deployment prosthesis (SL-AVR) or transcatheter aortic valve implantation (TAVI), achieves better perioperative survival for severe aortic stenosis (AS), we conducted direct-comparison meta-analyses (DC-MAs) and an adjusted indirect-comparison meta-analysis (IDC-MA).

METHODS

We searched MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials through April 2016. Eligible studies were randomized controlled trials (RCTs) and propensity-score matched (PSM) studies. We performed a DC-MA-[A] of SL-AVR versus TAVI, a DC-MA-[B] of SL-AVR versus conventional AVR (C-AVR), and a DC-MA-[C] TAVI versus C-AVR. Then, we computed a IDC-MA-[A'] of TAVI versus SL-AVR from the results of the DC-MA-[B] and the DC-MA-[C].

RESULTS

We identified 6 RCTs and 30 PSM studies enrolling a total of 15,887 patients. The 3 DC-MAs demonstrated significantly lower perioperative (30-day or in-hospital) all-cause mortality after SL-AVR than after TAVI (odds ratio [OR], 0.48; 95% confidence interval [CI], 0.28 to 0.80; p=0.005) and no significant differences between SL-AVR and C-AVR (OR, 1.07; 95% CI, 0.60 to 1.94; p=0.81) and between TAVI and C-AVR (1.07; 95% CI, 0.90 to 1.27; p=0.45). The computed IDC-MA-[A'] indicated no significant difference in mortality between SL-AVR and TAVI (1.01; 95% CI, 0.54 to 1.86). Combining the results of the DC-MA-[A] and IDC-MA [A'] showed significantly lower mortality after SL-AVR than after TAVI (OR, 0.65; 95% CI, 0.44 to 0.97; p=0.03).

CONCLUSIONS

For patients with severe AS, SL-AVR may achieve better perioperative survival than TAVI.

The effects of contrast media volume on acute kidney injury after transcatheter aortic valve replacement: a systematic review and meta-analysis

OBJECTIVE

The goal of this systematic review was to assess the effects of contrast media volume on transcatheter aortic valve replacement-related acute kidney injury.

METHODS

A literature search was performed using Medline, EMbase, the Cochrane Database of Systematic Reviews, and clinicaltrials.gov from the inception of these databases through December 2015. Studies that reported relative risk, odds ratio, or hazard ratio comparing the risks of acute kidney injury following transcatheter aortic valve replacement in patients who received high contrast media volume were included. Pooled risk ratio (RR) and 95% confidence intervals (95% CI) were calculated using a random-effect, generic inverse variance method.

RESULTS

Four cohort studies composed of 891 patients were included in the analyses to assess the risk of acute kidney injury after transcatheter aortic valve replacement in patients who received high contrast media volume. The pooled RR of acute kidney injury after transcatheter aortic valve replacement in patients who received a large volume of contrast media was 1.41 (95% CI, 0.87 to 2.28) compared with low contrast media volume. The meta-analysis was limited to studies using standard acute kidney injury definitions, and the pooled RR of acute kidney injury in patients who received high contrast media volume is 1.12 (95% CI, 0.78 to 1.62).

CONCLUSION

Our meta-analysis shows no significant association between contrast media volume and risk of acute kidney injury after transcatheter aortic valve replacement.

Transapical versus transfemoral approach and risk of acute kidney injury following transcatheter aortic valve replacement: a propensity-adjusted analysis

BACKGROUND

The aim of this study was to compare the incidence of post-procedural acute kidney injury (AKI) and other renal outcomes in patients undergoing transapical (TA) and transfemoral (TF) approaches for transcatheter aortic valve replacement (TAVR).

METHODS

All consecutive adult patients undergoing TAVR for aortic stenosis from 1 January 2008 to 30 June 2014 at a tertiary referral hospital were included. AKI was defined based on Kidney Disease Improving Global Outcomes (KDIGO) criteria. Logistic regression adjustment, propensity score stratification, and propensity matching were performed to assess the independent association between procedural approach and AKI.

RESULTS

Of 366 included patients, 171 (47%) underwent TAVR via a TA approach. AKI occurrence in this group was significantly higher compared to the TF group (38% vs. 18%, p < .01). The TA approach remained significantly associated with increased risk of AKI after logistic regression (OR 3.20; CI 1.68-4.36) and propensity score adjustment: OR 2.83 (CI 1.66-4.80) for stratification and 3.82 (CI 2.04-7.44) for matching. Nonetheless, there was no statistically significant difference among the TA and TF groups with respect to major adverse kidney events (MAKE) or estimated glomerular filtration rate (eGFR) at six months post-procedure.

CONCLUSION

In a cohort of patients undergoing TAVR for aortic stenosis, a TA approach significantly increases the AKI risk compared with a TF approach. However, the TAVR approach did not affect severe renal outcomes or long-term renal function.

Association of blood transfusion with acute kidney injury after transcatheter aortic valve replacement: A meta-analysis

AIM

To assess red blood cell (RBC) transfusion effects on acute kidney injury (AKI) after transcatheter aortic valve replacement (TAVR).

METHODS

A literature search was performed using MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, and clinicaltrials.gov from the inception of the databases through December 2015. Studies that reported relative risk, odds ratio or hazard ratio comparing the risks of AKI following TAVR in patients who received periprocedural RBC transfusion were included. Pooled risk ratio (RR) and 95%CI were calculated using a random-effect, generic inverse variance method.

RESULTS

Sixteen cohort studies with 4690 patients were included in the analyses to assess the risk of AKI after TAVR in patients who received a periprocedural RBC transfusion. The pooled RR of AKI after TAVR in patients who received a periprocedural RBC transfusion was 1.95 (95%CI: 1.56-2.43) when compared with the patients who did not receive a RBC transfusion. The meta-analysis was then limited to only studies with adjusted analysis for confounders assessing the risk of AKI after TAVR; the pooled RR of AKI in patients who received periprocedural RBC transfusion was 1.85 (95%CI: 1.29-2.67).

CONCLUSION

Our meta-analysis demonstrates an association between periprocedural RBC transfusion and a higher risk of AKI after TAVR. Future studies are required to assess the risks of severe AKI after TAVR requiring renal replacement therapy and mortality in the patients who received periprocedural RBC transfusion.

The risk of acute kidney injury following transapical versus transfemoral transcatheter aortic valve replacement: a systematic review and meta-analysis

Background

The aim of this systematic review is to examine the literature for the risk of acute kidney injury (AKI) in patients who underwent transcatheter aortic valve replacement (TAVR) based on transapical (TA) versus transfemoral (TF) approaches.

Methods

A literature search was conducted utilizing Embase, Medline, Cochrane Database of Systematic Reviews and ClinicalTrials.gov from inception through December 2015. Studies that reported relative risk, odds ratio or hazard ratio comparing the AKI risk in patients who underwent TA-TAVR versus TF-TAVR were included. Pooled risk ratio (RR) and 95% confidence interval (CI) were calculated using a random effect, generic inverse variance method.

Results

Seventeen cohort studies with 5085 patients were enrolled in the analysis to assess the risk of AKI in patients undergoing TA-TAVR versus TF-TAVR. The pooled RR of AKI in patients who underwent TA-TAVR was 2.26 (95% CI 1.79–2.86) when compared with TF-TAVR. When meta-analysis was confined to the studies with adjusted analysis for confounders evaluating the risk of AKI following TAVR, the pooled RR of TA-TAVR was 2.89 (95% CI 2.12–3.94). The risk for moderate to severe AKI [RR 1.02 (95% CI 0.57–1.80)] in patients who underwent TA-TAVR compared with TF-TAVR was not significantly higher.

Conclusions

Our meta-analysis demonstrates an association between TA-TAVR and a higher risk of AKI. Future studies are required to assess the risks of moderate to severe AKI and mortality following TA-TAVR versus TF-TAVR.

Transcatheter versus surgical aortic valve replacement in intermediate risk patients: a meta-analysis

BACKGROUND

Transcatheter aortic valve replacement (TAVR) has been approved in patients with high or prohibited surgical risk for surgery for treatment of severe symptomatic aortic stenosis. Prospective studies examining the benefits of TAVR in intermediate risk patients are ongoing. Other smaller studies including lower risk patients have been conducted, but further meta-analysis of these studies is required to draw more broad comparisons.

METHODS

A Medline search was conducted using standard methodology to search for clinical trials and observational studies including intermediate risk patients. We limited our meta-analysis to studies matching patient populations by propensity scores or randomization and examined clinical outcomes between TAVR and surgical aortic valve replacement (SAVR).

RESULTS

Analysis of the TAVR and SAVR cohorts revealed no significant differences in the outcomes of 30-day [OR (95% CI): 0.85 (0.57, 1.26)] or 1-year mortality [OR (95% CI): 0.96 (0.75, 1.23)]. A trend towards benefit with TAVR was noted in terms of neurological events and myocardial infarction (MI) without statistical significance. A statistically significant decrease in risk of post-procedural acute renal failure in the TAVR group [OR (95% CI): 0.52 (0.27, 0.99)] was observed, but so was a significantly higher rate of pacemaker implantations for the TAVR group [OR (95% CI): 6.51 (3.23, 13.12)].

CONCLUSIONS

We conclude that in intermediate risk patients undergoing aortic valve replacement, the risk of mortality, neurological outcomes, and MI do not appear to be significantly different between TAVR and SAVR. However, there appears to be a significant reduction in risk of acute renal failure at the expense of an increased risk of requiring a permanent pacemaker in low and intermediate risk patients undergoing TAVR compared to SAVR.

Transcatheter Aortic Valve Replacement: a Kidney's Perspective

Transcatheter aortic valve replacement (TAVR) has now emerged as a viable treatment option for high-risk patients with severe aortic stenosis (AS) who are not suitable candidates for surgical aortic valve replacement (SAVR). Despite encouraging published outcomes, acute kidney injury (AKI) is common and lowers the survival of patients after TAVR. The pathogenesis of AKI after TAVR is multifactorial including TAVR specific factors such as the use of contrast agents, hypotension during rapid pacing, and embolization; preventive measures may include pre-procedural hydration, limitation of contrast dye exposure, and avoidance of intraprocedural hypotension. In recent years, the number of TAVR performed worldwide has been increasing, as well as published data on renal perspectives of TAVR including AKI, chronic kidney disease, end-stage kidney disease, and kidney transplantation. This review aims to present the current literature on the nephrology aspects of TAVR, ultimately to improve the patients' quality of care and outcomes.

The comparison of the commonly used surrogates for baseline renal function in acute kidney injury diagnosis and staging

BACKGROUND

Baseline serum creatinine (SCr) level is frequently not measured in clinical practice. The aim of this study was to investigate the effect of various methods of baseline SCr determination measurement on accuracy of acute kidney injury (AKI) diagnosis in critically ill patients.

METHODS

This was a retrospective cohort study. All adult intensive care unit (ICU) patients admitted at a tertiary referral hospital from January 1, 2011 through December 31, 2011, with at least one measured SCr value during ICU stay, were included in this study. The baseline SCr was considered either an admission SCr (SCrADM) or an estimated SCr, using MDRD formula, based on an assumed glomerular filtration rate (GFR) of 75 ml/min/1.73 m(2) (SCrGFR-75). Determination of AKI was based on the KDIGO SCr criterion. Propensity score to predict the likelihood of missing SCr was used to generate a simulated cohort of 3566 patients with baseline outpatient SCr, who had similar characteristics with patients whose outpatient SCr was not available.

RESULTS

Of 7772 patients, 3504 (45.1 %) did not have baseline outpatient SCr. Among patients without baseline outpatient SCr, AKI was detected in 571 (16.3 %) using the SCrADM and 997 (28.4 %) using SCrGFR-75 (p < .001). Compared with non-AKI patients, patients who met AKI only by SCrADM, but not SCrGFR-75, were significantly associated with 60-day mortality (OR 2.90; 95 % CI 1.66-4.87), whereas patients who met AKI only by SCrGFR-75, but not SCrADM, had a non-significant increase in 60-day mortality risk (OR 1.33; 95 % CI 0.94-1.88). In a simulated cohort of patients with baseline outpatient SCr, SCrGFR-75 yielded a higher sensitivity (77.2 vs. 50.5 %) and lower specificity (87.8 vs. 94.8 %) for the AKI diagnosis in comparison with SCrADM.

CONCLUSIONS

When baseline outpatient SCr was not available, using SCrGFR-75 as surrogate for baseline SCr was found to be more sensitive but less specific for AKI diagnosis compared with using SCrADM. This resulted in higher incidence of AKI with larger likelihood of false-positive cases.