Patient's Radiation Exposure in Coronary Angiography and Angioplasty: The Impact of Different Projections

Establishing a priori and a posteriori predictive models to assess patients' peak skin dose in interventional cardiology. Part 2: results of the VERIDIC project

BACKGROUND

Optimizing patient exposure in interventional cardiology is key to avoid skin injuries.

PURPOSE

To establish predictive models of peak skin dose (PSD) during percutaneous coronary intervention (PCI), chronic total occlusion percutaneous coronary intervention (CTO), and transcatheter aortic valve implantation (TAVI) procedures.

MATERIAL AND METHODS

A total of 534 PCI, 219 CTO, and 209 TAVI were collected from 12 hospitals in eight European countries. Independent associations between PSD and clinical and technical dose determinants were examined for those procedures using multivariate statistical analysis. A priori and a posteriori predictive models were built using stepwise multiple linear regressions. A fourfold cross-validation was performed, and models' performance was evaluated using the root mean square error (RMSE), mean absolute percentage error (MAPE), coefficient of determination (R²), and linear correlation coefficient (r).

RESULTS

Multivariate analysis proved technical parameters to overweight clinical complexity indices with PSD mainly affected by fluoroscopy time, tube voltage, tube current, distance to detector, and tube angulation for PCI. For CTO, these were body mass index, tube voltage, and fluoroscopy contribution. For TAVI, these parameters were sex, fluoroscopy time, tube voltage, and cine acquisitions. When benchmarking the predictive models, the correlation coefficients were r = 0.45 for the a priori model and r = 0.89 for the a posteriori model for PCI. These were 0.44 and 0.67, respectively, for the CTO a priori and a posteriori models, and 0.58 and 0.74, respectively, for the TAVI a priori and a posteriori models.

CONCLUSION

A priori predictive models can help operators estimate the PSD before performing the intervention while a posteriori models are more accurate estimates and can be useful in the absence of skin dose mapping solutions.

[X-Ray, false friend of the interventional cardiologist - Risks, evaluation, quality improvement - Status report from France-PCI registry]

Although indispensable, radiation exposure during cardiac catheterization procedures can cause specific radiation-induced diseases. These affect the patient but also the interventional cardiologist. Exposure to high or repeated radiation doses causes deterministic effects. Moreover, even low-dose exposure, especially when repeated, produces a risk of stochastic effets. In that respect, it is crucial to improve the radiation safety of cardiac angiography and interventions, to promote radiation protection and to maintain this exposure « As Low As Reasonably Achievable ». Thus, there is a necessity to spread knowledge about safety standards and recommandations to reduces the dose among interventionalists. Data collection and comparaison of practices are precious to this quality improvement process. For the year 2020, France-PCI registry had collected dosimetric datas related to 55 783 coronary angiographic and interventional procedures from 30 centers in France. Mean fluoroscopy time was 4,4 minutes for diagnostic procedures. Mean PDS was 1 767cGy.Cm2 and mean Air Kerma de 257Gy. Coronary percutaneous angioplasty procedures were related to approximately two to three times higher mean exposures. Mean exposure related to chronic coronary total occlusion treatment procedures was also two times higher than exposure related to non-CTO interventions. These data also highlighted wide disparities between centers.

IMPACT OF PELVIC AND RAD-BOARD LEAD SHIELDS ON OPERATOR AND PATIENT RADIATION DOSE IN TRANS-RADIAL CORONARY PROCEDURES

BACKGROUND

Trans-radial approach for cardiac catheterisation procedures has long been associated with high operator and patient radiation dose. The aim of the present study was to determine the effect of pelvic and radial shields on decreasing coronary procedure radiation doses.

METHODS

A total of 418 patients randomly underwent diagnostic and therapeutic cardiac procedures with and without the pelvic and rad-board lead shields during the procedures. The operator and patient doses were then determined by means of a personal dosimeter and dose area product (DAP), respectively.

RESULTS

The shields decreased the operator radiation dose by 40% in coronary angiography (CA) and by 45% during angioplasty (PCI). These results were achieved at the cost of increased patient radiation dose.

CONCLUSION

Pelvic lead shields combined with rad-board shields are highly effective in reducing operator radiation dose in trans-radial approach, but it is only achieved at the cost of increased patient DAP.

Beam projections and radiation exposure in transradial and transfemoral approaches during coronary angiography

OBJECTIVE

We aimed to compare the operator and patient radiation exposure in standard projections during elective diagnostic coronary angiography procedures via transradial (TRA) versus transfemoral (TFA) approaches.

METHODS

In this analytical cross-sectional study, a total of 202 consecutive patients who were candidates for diagnostic coronary angiography were randomized to undergo the procedure via TFA or TRA approaches (101 in each group). Patients with abnormal Allen test and history of coronary artery bypass surgery, valvular heart disease, and unsuccessful coronary angiography were excluded from the study. A single operator performed all of the procedures using a single angiography system. Patient and operator radiation exposure were measured using diamentor and an electronic personal dosimeter, respectively. Each procedure comprised a standardized sequence of projections including four standard views for the left coronary system and two standard views for the right coronary system.

RESULTS

Left anterior oblique (LAO) caudal (50°/30°) and right anterior oblique RAO (30°) projections were associated with the highest and lowest patient radiation exposure, respectively. The operator received a significantly higher radiation exposure in the TRA approach for LAO cranial (for both left and right coronary systems) and LAO caudal (for left coronary system) projections during coronary angiography compared with the TFA approach.

CONCLUSION

Though a similar amount of patient radiation exposure in each projection was observed among TFA and TRA groups; LAO cranial and LAO caudal projections were associated with a significantly higher operator radiation exposure in the TRA group. These findings need to be considered when choosing the optimal arterial approach for patients scheduled for coronary angiography.

Comparison of the patient radiation exposure during coronary angiography and angioplasty procedures using trans-radial and trans-femoral access

INTRODUCTION

Cardiac catheterization procedure through the trans-radial access (TRA) have shown many clinical advantages over the trans-femoral (TFA), but despite its advantages, there are serious concerns regarding higher possible radiation dose for the patients and operators in TRA. This study was planned to compare the patients' radiation dose associated with TRA and TFA during coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA).

METHODS

Of 700 candidates for angiography, 326 patients were entered the study. All the procedures were carried out by one interventional cardiologist employing the same angiography unit in Aalinasab hospital and the patients' dose area product (DAP), air kerma (AK), fluoroscopy time (FT) and cine film time (CFT) were then determined in both access groups (TRA,TFA) in CA, PTCA and CA+PTCA procedures.

RESULTS

The mean FT, CFT and AK values in both TRA & TFA groups were the same in all procedures (P>0.05). The mean DAP in CA+PTCA procedures was 6704.01±3243.23 µGym(2) in femoral access compare with 5647.46±2797.74 µGym(2) in radial access, which were significantly less than that in TFA with P= 0.02.

CONCLUSION

On the basis of the results obtained in this study, no differences were found in patients' radiation dose in both access groups, therefore with regard to comparatively more clinical advantages associated with the Trans-radial access technique it might be a good substitute for Trans-femoral access.

Radiation doses and estimated risk from angiographic projections during coronary angiography performed using novel flat detector

Coronary angiography (CA) procedure uses various angiographic projections to elicit detailed information of the coronary arteries with some steep projections involving high radiation dose to patients. This study intends to evaluate radiation doses and estimated risk from angiographic projections during CA procedure performed using novel flat detector (FD) system with improved image processing and noise reduction techniques. Real‐time monitoring of radiation doses using kerma‐area product (KAP) meter was performed for 140 patients using Philips Clarity FD system. The CA procedure involved seven standard projections, of which five were extensively selected by interventionalists. Mean fluoroscopic time (FT), KAP, and reference air kerma (Ka,r) for CA procedure were 3.24 min (0.5–10.51), 13.99 Gycm² (4.02–37.6), and 231.43 mGy (73.8–622.15), respectively. Effective dose calculated using Monte Carlo‐based PCXMC software was found to be 4.9 mSv. Left anterior oblique (LAO) 45° projection contributed the highest radiation dose (28%) of the overall KAP. Radiation‐induced risk was found to be higher in females compared to males with increased risk of lung cancer. An increase of 10%–15% in radiation dose was observed when one or more additional projections were adopted along with the seven standard projections. A 14% reduction of radiation dose was achieved from novel FD system when low‐dose protocol during fluoroscopy and medium‐dose protocol during cine acquisitions were adopted, compared to medium‐dose protocol.

PACS number(s): 87.50.cm, 87.55.de, 87.55.N, 87.59.cf, 87.59.Dj