25 TAVI operator radiation dose compared to PCI and ICD operators: do we need additional radiation protection for trans-catheter structural heart interventions

Exposure to Ionizing Radiation in Patients Undergoing Transfemoral Transcatheter Aortic Valve Implantation

Transcatheter aortic valve implantation (TAVI) is currently becoming an alternative to surgical valve replacement for patients at low risk, a population that is likely to experience an increase in the radiation-induced cancer risk following TAVI. We aimed to evaluate the overall exposure to ionizing radiation in patients who underwent transfemoral TAVI, including the procedure itself as well as the procedures performed in the preintervention work-up and the post-TAVI interventions. All patients who underwent transfemoral TAVI for symptomatic aortic stenosis in our center over a 26 months period were included. Dosimetric indicators from preprocedural coronary angiography and computed tomography (CT), the TAVI procedure, and any postprocedural interventions (electrophysiology study and/or pacemaker implantation) were collected and converted into an effective dose. A total of 119 transfemoral TAVI procedures were included. The mean cumulative effective dose (ED) was 37.3 mSv. Three irradiating procedures were necessary for 84 patients (71% of the population, i.e., coronary angiography, CT scan and the TAVI procedure itself), whereas 30 patients (25%) required a fourth procedure, and 5 required a fifth (4%). The majority of the dose was from the CT, while only 11% of the dose derived from the TAVI procedure itself. In conclusion, overall exposure to ionizing radiation for patients who underwent transfemoral TAVI seems acceptable, and the majority of the overall ED comes from the CT scan.

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 the impact on radiation dose and image quality of a new cardiac interventional X-ray system for trans-catheter aortic valve implantation (TAVI) patients compared to the previously-used cardiac X-ray system.

METHODS

Patient dose and image data were retrospectively collected from a Philips AlluraClarity (new) and Siemens Axion Artis (reference) X-ray system. Patient dose area product (DAP) and fluoroscopy duration of 41 patient cases from each X-ray system were compared using a Wilcoxon test. Ten patient aortograms from each X-ray system 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.

RESULTS

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%. There was no significant difference between image quality scores of 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 of cardiac patients and particularly on operators including anaesthetists; cumulative exposure of interventional cardiologists performing high volume TAVI over 30-40 years may be harmful. The Phillips Clarity upgrade including improved image enhancement and optimised X-ray settings significantly reduced radiation without reducing clinically acceptable image quality.