Abstract
Objective
The aim of this study was to assess the impact of the ratio of volume of contrast medium to the glomerular filtration rate (V/GFR) on acute kidney injury (AKI) after transcatheter aortic valve implantation (TAVI) and its impact on long-term mortality.
Methods
We retrospectively calculated V/GFR in 397 patients undergoing TAVI. AKI was defined as VARC-modified Risk, Injury, Failure, Loss and End-stage (RIFLE) kidney disease score ≥ 2.
Results
The incidence of AKI was 17.9%. The mean V/GFR ratio was 3.0 ± 2.7 in patients without AKI and 7.8 ± 8.8 in patients with AKI ( p < 0.001). The receiver–operator characteristic curve analysis showed fair discrimination between patients with and without AKI (C-statistic 0.85) at a V/GFR ratio of 3.2. Multivariable regression analysis indicated that V/GFR > 3.2 was an independent predictor of both AKI (OR 3.4, 95% CI 1.0–6.1, p < 0.001) and long-term mortality (OR 3.3, 95% CI 2.0–5.2, p < 0.001).
Conclusions
A V/GFR > 3.2 was found to be correlated with a higher incidence of AKI and mortality after TAVI. Therefore, this ratio could potentially be used to calculate the maximum volume of contrast medium that can be administered without significantly increasing the risk of AKI and mortality. Further larger studies are needed to validate these findings.
Highlights
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The association between high contrast media volume and the risk of acute kidney injury following transcatheter aortic valve implantation is not fully understood.
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We observed that a ratio of contrast volume/glomerular filtration ratio > 3.2 identifies patients at significantly increased risk of acute kidney injury.
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This index may be a useful tool in determining the amount of contrast volume that can be safely administered during transcatheter aortic valve implantation.
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Moreover, after the procedure a V/GFR > 3.2 may identify a subset of patients at increased risk of AKI and of short and long-term mortality, in whom it will be useful to perform careful and prolonged monitoring of renal function.
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Introduction
Transcatheter aortic valve implantation (TAVI) is now an established treatment option for non-surgical patients with severe aortic stenosis. However, its benefit may be limited by the development of acute kidney injury (AKI), a complication associated with prolonged hospitalization and increased in-hospital and long-term mortality . AKI after TAVI procedures may be related to several causes such as: advanced age, comorbidity, contrast media, the systematic occurrence of short periods of extreme hypotension (during rapid pacing, balloon valvuloplasty and valve deployment), bleeding and anemia, and cholesterol embolization due to the manipulation of large catheters in the aorta of patients with a high prevalence of diffuse atherosclerosis. However, to date the exact role played by the toxicity of contrast medium in the pathogenesis of TAVI-induced AKI is not well described.
In the setting of angiography and percutaneous coronary interventions (PCI), the amount of contrast medium administered during the procedure normalized to baseline renal function was generally shown to have a linear correlation with the risk of AKI. In fact, several studies underlined an association between absolute and weight- and creatinine-adjusted (or GFR-adjusted) contrast volume and contrast induced nephropathy . A number of studies have analyzed the predictors of AKI after TAVI ; but less work has been carried regarding the effects of contrast media volume on AKI after TAVI .
Thus, the objective of our study was to assess the relationship between contrast volume administered and risk of AKI, and the effect on short and long-term outcomes in patients with severe aortic stenosis undergoing TAVI.
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