Discussion
The TRA approach for neuroendovascular procedures has continued to gain traction over the past several years. Recent neurointerventional and cardiointerventional studies15 16 have reported higher patient and operator preference for TRA over TFA because of a wide array of benefits, including reductions in access site-related morbidity, length of stay, major bleeding and shorter time to ambulation.1–5 10 11 However, a drawback finding in our study about patient radiation dose exposure during the initial TRA-adoption phase offers an additional perspective to TRA and TFA comparative studies.
In our first comparative analysis, TRA was found to be associated with a significantly higher radiation exposure than in TFA. In our study, we only analysed diagnostic angiograms and excluded therapeutic interventions to eliminate the complexity of treatment procedures which prolonged procedure and FT. This study was also performed during our institution’s transition to a ‘radial first’ practice. Similar higher FT in TRA have been reported in comparative studies that analysed FT as a secondary variable,3 9 and others that analysed both diagnostic and therapeutic procedures together.4 9 A possible explanation for this finding is the steep learning curve which remains a significant challenge for experienced Neurointerventionalists trained initially with TFA.2 17–19 ,20 We did not study if there is a learning curve but it is presumed from these reports that after performing 30–50 cases it can be overcome with a significant decrease in FT and improved injection success rate.
Another contributing factor was the catheters used by the initial adopters in our study which were not specifically designed for the TRA. A recent national survey2 reported that neurointerventionalists would prefer modified and improved tools designed specifically for TRA, mostly because of the technical and intraoperative challenges resulting from aforementioned comorbidities, and anatomical variants associated with the transradial route13 ultimately leading to increased vascular access time.
We explored other (confounding) variables that affected FT. Considering age as one of the factors described in previous studies,3 4 13 21 we performed an additional comparative analysis in the TRA group between the elderly (>65) and younger (<65) patients. We discovered that it may be more challenging in attaining a predefined complete 6-vessel DCA in the elderly compared with their younger counterparts with a significant increase in radiation exposure as well. Our analysis also pointed to higher cardiovascular comorbidities in the elderly as another contributing factor. Other studies3 13 21 have also demonstrated age as a predictor of failed TRA because of associated sicknesses and higher incidences of pathologic/tortuous vessel morphology in the elderly (>65 years). However, it remains unclear from our study whether better techniques and tools could have led to a complete 6-vessel DCA regardless of atherosclerosis or other pathological factors.
With the number of vessels being a confounder in the elderly population affecting FT, we performed several analyses to establish this relationship. We first compared the 6-vessel DCA cohort to a less tha 6-vessel DCA which showed a greater percentage of patients in the less than 6-vessel cohort being older (>65 years) with comorbid CVD and a corresponding higher FT. Furthermore, linear modelling (figure 2) showed that with every increase of 1 vessel the FT was a minute greater in TRA comparing to TFA. To our knowledge, no prior study has examined the relationship between these confounders affecting radiation exposure.
We reported that the type of vascular approach (TRA and TFA) did not affect the 30 days post-operative PROGHS QOL outcomes even though the majority of TRA approaches were performed in the outpatient setting (table 1). We chose to use the 10-item Patient-Reported Outcomes measurement Information System GHS because it is a well-known valid and reliable scale used in assessing and tracking the impact of healthcare interventions in health and functional disability over time. This novel finding from our 30-day postprocedural PRO adds to previous literature1–5 that only reported immediate QOL outcome with the TRA approach during the postoperative phase. These studies demonstrated a higher satisfaction rate with the radial approach mainly because of a shorter recovery time likely related to postprocedural comfort and reduced hospital stay. In our study, we did not report complication rates and cross-over cases (n=3) because first, they were too few, and second, they were not our main variables of interest in this study. Numerous previous studies have compared complications rates favouring the TRA approach.1–5 10 11
Our study has some limitations. First, our study has the inherent limitations of a retrospective study. Second, we did not include therapeutic procedures in this study. Third, we were unable to assess the learning curve because our analysis was performed during the initial TRA-adoption period. Fourth, our sample size was relatively low due to the following reasons. Patients who were lost to follow-up at 30 days were not included and that may have created a type of selection bias. Another limitation was that we excluded and did not analyse crossover cases from TRA to TFA which were only a few cases. Despite the low sample size, our results were still significant, and this speaks to the major difference in radiation dose exposure between TRA and TFA.
Our study had multiple unique strengths. First, we were able to use detailed sociodemographic and hospital data including many possible confounding variables (number of vessels successfully catheterised and 3D rotational angiograms) to complete a multivariate analysis in our study. Second, we focused on only diagnostic cerebrovascular procedures, which to our knowledge has not been reported in the literature to date for in-depth comparative radiation exposure parameters analysis. Third, all DCAs were performed with only the Biplane-Siemens Artis Q catheterisation lab. Fourth, we used widely accepted scales for functionality and overall global health in clinical outcomes analysis. Fifth, our broader inclusion criteria including age, comorbid conditions and preoperative diagnosis allowed for a more representative and generalisable sample in the setting of cerebrovascular diseases to limit selection bias.
The neurointerventionalist community largely agrees that TRA improves patient comfort, and overall there is no concern about TRA’s safety for diagnostic or therapeutic interventions. However, the increased radiation dose exposure reported in our study is a substantial drawback. With the growing trend to perform TRA DCAs, future research should address better radiation dose reduction technical skills and strategies, and the development of more TRA-specific devices.
