Abstract 9418: Contrast Volume to Estimated Glomerular Filtration Rate Ratio as a Predictor for 30-Day All-Cause Mortality After Transcatheter Aortic Valve Implantation

Abstract

Introduction: Contrast-induced acute kidney injury (AKI) has been proven to be associated with early mortality and adverse events. However, in the setting of transcatheter aortic valve implantation (TAVI), previous literature has failed to establish a correlation between the absolute volume of contrast media administered and mortality. Objective: We aimed to investigate the impact of contrast volume administered normalised to estimated glomerular filtration rate ratio (V/eGFR) on 30-day all-cause mortality in TAVI patients. Secondary outcomes were AKI and new renal replacement therapy (RRT). Methods: We retrospectively analysed a cohort of 1150 patients who underwent TAVI at our unit between 2015-2018. Results: Follow-up was complete for all patients. There were 23 deaths within the follow-up period. Receiver operating curve (ROC) analysis showed fair discrimination for 30-day all-cause mortality at a V/eGFR ratio of 3.6 (C-statistic 0.68). 69.7% (n=801) of patients had a V/eGFR of <3.6 and 30.3% (n=349) had a V/eGFR of ≥3.6. In multivariate Cox proportional hazards analysis, V/eGFR as a cut point ≥3.6 was the strongest predictor of 30-day all-cause mortality (hazards ratio 4.35, 95% confidence interval [1.74-10.89], p=0.002). Other independent predictors were procedural urgency (3.40 [1.46-7.92]) and being under general anaesthesia (4.23 [1.62-11.08]). In Kaplan-Meier analysis, patients with V/eGFR ≥3.6 had a significantly greater 30-day mortality than those <3.6 (log rank test p<0.0001). A similar V/eGFR cut point of 3.6 was found to be an excellent predictor for new RRT (C-statistic 0.82), and 3.3 for AKI (C-statistic 0.60). Conclusions: In conclusion, a V/eGFR ≥3.6 after TAVI was found to be a strong predictor of 30-day mortality. The maximum contrast volume which can be safely administered in each patient without significantly increasing the risk of mortality can be calculated using this ratio. Future studies are indicated to validate our findings.