Impact of Near-Term Contrast Application Prior to TAVI on Postoperative Renal Failure

Objectives: TAVI is an alternative treatment option for high-risk patients with aortic valve disease who are ineligible for conventional surgical valve replacement. Almost all patients undergo both multi slice computed tomography scan (CT) and coronary angiogram (CA) prior to TAVI. Postoperative renal failure is a known significant risk factor for prolonged hospital stay and is associated with a two- to sixfold higher mortality in the TAVI collective.

Aim of our study was to examine whether the timespan between the last preoperative application of contrast agent (CT or CA) and the procedure influences renal failure defined by VARC-2 criteria. Results may influence the preoperative strategy regarding the timing of the diagnostics.

Methods: A total of 656 consecutive patients were screened from December 2013 to August 2016. Exclusion criteria were chronic dialysis and critical preoperative state as defined by the EuroScore study group. Based on these criteria, 603 patients were included in the study. According to the last diagnostic contrast application, one group with near-term contrast exposure (NT, 1–3 days) and one group with long-term contrast exposure (LT, ≥4 days) prior to TAVI were formed. Postoperative renal failure was defined using the AKIN 2 criteria according to VARC-2 (increase of GRF >200% of baseline value or renal replacement therapy). Bias by comorbidities and impact of renal outcome by different amounts of intraoperatively used contrast agent could be excluded. Statistical analysis was performed using Student t-test and Pearson chi-square test. SPSS version 23 was used for statistical calculations.

Results: There was no significant difference in GFR impairment (NT: −9.8 ± 17.5 mL/min vs. LT: −7.9 ± 15.6 mL/min; p = 0.21), VARC-2 relevant acute kidney injury (NT: n = 18 (9.9%) vs. LT: n = 27 (6.4%); p = 0.13), need for postoperative renal replacement therapy (NT: n = 9 (5.0%) vs. LT n = 13 (3.1%); p = 0.26) or 30-day mortality (NT: n = 9 (5.2%) vs. LT: n = 15 (3.8%); p = 0.43).

Conclusion: The timing of the last diagnostic examination that requires contrast agent prior to TAVI did not show significant impact in our study. Therefore, a fast track approach to minimize preoperative hospital stay seems to be secure in general. However, especially in patients with preoperatively impaired renal function, further data about the best strategy is missing.