Non-contrast transcatheter aortic valve implantation for patients with aortic stenosis and chronic kidney disease: a pilot study

Zero-Contrast Transcatheter Aortic Valve Implantation vs. Standard Practice: Periprocedural and Long-Term Clinical Outcomes

Background: We aimed to compare the procedural efficacy and long-term clinical results of a totally contrast-free Transcatheter Aortic Valve Implantation (TAVI) procedure (i.e., contrast dye was not used for either the pre-procedural assessment or during the procedure) to those of standard practice in patients with severe renal dysfunction. Methods: All consecutive patients with a glomerular filtration rate (GFR) ≤ 35 mL/min and severe aortic stenosis who were treated with transfemoral TAVI at our Institution were included in the registry. The zero-contrast patients underwent carbon dioxide angiography and a non-contrast CT scan for assessment of vascular access suitability, and aortic annulus sizing was performed by a TEE, and the procedural guidance was fluoroscopic and echocardiographic. Procedural outcomes were evaluated, and clinical long-term follow-up was performed for all included patients. Results: A total of 44 patients (median age, 85 (IQR, 80.75-87.00)) were included in the zero-contrast group (TEE guidance and general anesthesia in 37 (84%) patients), while 63 patients were included in the standard practice arm (82 ± 78 mL of contrast dye used). Procedural success was obtained in 100% of cases. There were no differences in procedural outcomes, including final mean aortic gradients (5.5 (IQR, 5.0-10.0) mmHg in the zero-contrast group vs. 6.0 (IQR, 5.0-10.0) mmHg in the standard practice group) and rate of at least a moderate paravalvular leak (0% vs. 1.6% in the zero-contrast and standard practice groups, respectively; p = 0.31). No differences in AKI during the hospital stay were observed. Over a median follow-up of 3.3 years, there was a significantly lower rate of AKI (1.2% vs. 25.9%, p < 0.001) and rehospitalizations (1.6% vs. 35.5%, p < 0.00) in standard practice group. Conclusions: We showed for the first time the feasibility and efficacy of a totally contrast-free strategy compared to standard practice in TAVI patients with severe renal dysfunction. Besides achieving comparable procedural results, the zero-contrast strategy showed a better long-term clinical outcome in reducing hospital readmissions for kidney function deterioration.

Pre-Procedural Assessment of the Femoral Access Route for Transcatheter Aortic Valve Implantation: Comparison of a Non-Contrast Time-of-Flight Magnetic Resonance Angiography Protocol with Contrast-Enhanced Dual-Source Computed Tomography Angiography

Background: We aimed to evaluate the feasibility of a non-contrast time-of-flight magnetic resonance angiography (TOF-MRA) protocol for the pre-procedural access route assessment of transcatheter aortic valve implantation (TAVI) in comparison with contrast-enhanced cardiac dual-source computed tomography angiography (CTA). Methods and Results: In total, 51 consecutive patients (mean age: 82.69 ± 5.69 years) who had undergone a pre-TAVI cardiac CTA received TOF-MRA for a pre-procedural access route assessment. The MRA image quality was rated as very good (median of 5 [IQR 4-5] on a five-point Likert scale), with only four examinations rated as non-diagnostic. The TOF-MRA systematically underestimated the minimal effective vessel diameter in comparison with CTA (for the effective vessel diameter in mm, the right common iliac artery (CIA)/external iliac artery (EIA)/common femoral artery (CFA) MRA vs. CTA was 8.04 ± 1.46 vs. 8.37 ± 1.54 (p < 0.0001) and the left CIA/EIA/CFA MRA vs. CTA was 8.07 ± 1.32 vs. 8.28 ± 1.34 (p < 0.0001)). The absolute difference between the MRA and CTA was small (for the Bland-Altman analyses in mm, the right CIA/EIA/CFA was -0.36 ± 0.77 and the left CIA/EIA/CFA was -0.25 ± 0.61). The overall correlation between the MRA and CTA measurements was very good (with a Pearson correlation coefficient of 0.87 (p < 0.0001) for the right CIA/EIA/CFA and a Pearson correlation coefficient of 0.9 (p < 0.0001) for the left CIA/EIA/CFA). The feasibility agreement between the MRA and CTA for transfemoral access was good (the right CIA/EIA/CFA agreement was 97.9% and the left CIA/EIA/CFA agreement was 95.7%, Kohen's kappa: 0.477 (p = 0.001)). Conclusions: The TOF-MRA protocol was feasible for the assessment of the access route in an all-comer pre-TAVI population. This protocol might be a reliable technique for patients at an increased risk of contrast-induced nephropathy.