Incidence, risk factors and prognosis of acute kidney injury after transcatheter aortic valve implantation.

AIM:   Transcatheter aortic valve implantation (TAVI) poses a significant risk of acute kidney injury (AKI). Little is known of the impact of TAVI and AKI on long-term kidney function and health cost. We explored the predictive factors and prognostic implications of AKI following TAVI.

METHODS:   Single-centre retrospective analysis of 52 elderly patients undergoing TAVI was conducted. The primary endpoint was renal outcome which included the incidence of AKI and 12-month renal function after TAVI. Secondary endpoints were mortality, the length of hospital stay (LOS) and cost.

RESULTS:   AKI occurred in 15/52 (28.8%) patients (mean age 84 ± 6) and three patients (6%) required dialysis. Patients with AKI (AKI+) had greater comorbidity (diabetes and cerebrovascular disease) and a trend towards reduced estimated glomerular filtration rate (eGFR) at baseline compared with those without AKI (56.6 vs AKI-: 65.7 mL/min per 1.73 m(2) , P = 0.07). Following TAVI, AKI- patients experienced an immediate improvement in eGFR, which remained significantly higher at all time points compared with AKI+ patients (70.4 vs 46.9 at 6 months and 73.7 vs 53.0 at 12 months, P < 0.001). Cumulative mortality for AKI+versus AKI- group was 26.7% and 2.7% (P = 0.006). LOS doubled (P < 0.001) and average hospitalization cost per patient was 1.5 times higher in the AKI+ group (P < 0.001). Independent predictors of AKI were peri-procedural blood transfusion (OR: 2.4, 95% CI: 2.0-3.1), trans-apical approach (OR: 9.3, 95% CI: 4.3-23.7) and hypertension (OR: 6.4, 95% CI: 2.9-17.3).

CONCLUSION:   AKI developed in 28.8% of patients after TAVI and was associated with procedural technique and transfusion requirement, and an increased LOS and mortality. However, most patients achieved a significant and sustained improvement in eGFR.