Impact of latest generation cardiac interventional X-ray equipment on patient image quality and radiation dose for trans-catheter aortic valve implantations

OBJECTIVES: This study aimed to determine whether a reduction in radiation dose was found whilst maintaining a clinically acceptable level of image quality for trans-catheter aortic valve implantation (TAVI) patients using a new cardiac interventional X-ray system with state-of-the-art image enhancement and X-ray optimisation, compared to the cardiac X-ray system which was previously used for TAVI (the reference system). METHODS: Patient dose and image data were retrospectively collected from an AlluraClarity (Philips Healthcare) and Axion Artis (Siemens Healthcare), the new and reference X-ray systems respectively. Patient procedure dose area product (DAP) and fluoroscopy duration of 41 patient cases from each X-ray system were compared using a Wilcoxon test on median values. Significant reductions in patient dose (p<<0.001) were found for the new system with no significant change in fluoroscopy duration (p=0.052); procedure DAP reduced by 55%, fluoroscopy DAP by 48% and “cine” acquisition DAP by 61%. Ten patient aortograms from each X-ray system (20 total) were scored by 32 observers on a continuous scale to assess the clinical image quality at the given phase of the TAVI procedure. Scores were dichotomised by acceptability and analysed using a Chi-squared test; there was no significant difference between the two X-ray systems (p=0.06). CONCLUSIONS: The new cardiac X-ray system demonstrated a very significant reduction in patient dose with no loss of clinical image quality. ADVANCES IN KNOWLEDGE: The huge growth of TAVI may impact on the radiation exposure incurred by cardiac patients and particularly on operators including not only interventional cardiologists, also anaesthetists for TAVI procedures; the cumulative exposure to interventional cardiologists performing high volume TAVI over a 30 - 40 year career may be harmful. The Phillips Clarity upgrade including improved digital image enhancement and optimised X-ray settings significantly reduced the amount of radiation used without reducing clinically acceptable image quality.