Effect of low contrast medium-dose CTA on device sizing and access vessel assessment for TAVR

Abstract

PurposeChronic kidney disease (CKD) is prevalent in transcatheter aortic valve replacement (TAVR) candidates, leading to concerns regarding contrast medium (CM) safety. We evaluated (a) the impact of low-CM imaging on pre-TAVR measurements and (b) postcontrast acute kidney injury (PC-AKI) prevalence after dual-source computed tomography (DSCT) in TAVR candidates. MethodsAll TAVR candidates with CKD (SCr≥1.5 mg/dL) who underwent weight-based low-CM, low-pitch helical 3rd-generation DSCT in a one-year period were included, and matched to standard-CM, non-CKD controls (N = 50). Image quality (IQ) and pre-TAVR measurement interobserver variability were evaluated. Renal function change and PC-AKI were studied in the entire TAVR cohort, irrespective of scan mode (N = 153). ResultsLow-CM in CKD (N = 25) was performed with median 68 mL CM [52–87], 90 kV [80–90] and SCr 1.6 mg/dL [1.5–1.9], and standard-CM without CKD with median 116 mL CM [96–134], 100 kV [90–110] and SCr 1.0 mg/dL [0.9–1.1](P < 0.00). Low-CM IQ was good, though lower compared with standard-CM (P < 0.02). Interobserver measurement reliability was excellent (ICCs>0.85). Interobserver-agreement was lower in low-CM, causing prosthesis size disagreement in 5/25 (kappa-0.73) versus 0/25 with standard-CM (kappa-1.00), and transfemoral eligibility disagreement in 4/25 (kappa-0.68) versus 2/25 (kappa-0.84), respectively. Mean 1-month SCr-change in the low-CM TAVR cohort (N = 35) was −1 % [−12 to +7 %] and in standard-CM (N = 118) 0 % [−8 to +10 %](P > 0.3). PC-AKI occurred in none. ConclusionLow-CM third-generation-DSCT achieves good IQ in TAVR candidates with CKD, and seems safe, with no apparent renal function deterioration or prevalence of PC-AKI. However, standard-CM protocols in non-CKD patients provide higher measurement reproducibility. Low-CM protocols should therefore be reserved for patients at high risk for PC-AKI.