On Radiation Protection: Editorial comment by Dr. Ariel Durán

Courtesy of Dr. Ariel Durán.

I am pleased to witness the increased amount of scientific papers in high impact journals addressing topics related to radiation protection or the harmful effects of radiation on our patients and primary or secondary operators. Similarly, it is my pleasure to see that SOLACI has acknowledged this growing concern by selecting 5 articles for comment on its website in this occasion.

The selected articles differ in applicability, novelty, and importance; thus, I mean to share my opinion and, ultimately, provide additional information published a mere couple of weeks ago in Circulation.

As regards the article on chronic total occlusions, “Radiation exposure of patients during chronic total occlusion percutaneous coronary intervention. Update from a Contemporary Multicenter Registry” (Karacsonyi J. et al.), which was recently presented at the 2017 American Heart Association Sessions, the fact that the radiation dose is higher as procedural time increases is well-known. Operator experience and the availability of materials required for procedural success obviously result in lower patient and operator exposure in dedicated centers. In my opinion, this is the best scenario.

Read also: “Radiation Exposure in Chronic Total Occlusions”.

While the article “Efficacy of the RADPAD Protection Drape in Reducing Operators’ Radiation Exposure in the Catheterization Laboratory. A Sham-Controlled Randomized Trial” (Wieneke Vlastra et al.) dealt with a considerable number of patients, results are curious because the use protective shielding without lead (blinded for operators) was associated to higher radiation dose than their lack of use. Certainty would require a larger number of patients. On the other hand, industry pressure to implement these elements must be assessed cautiously, given the high cost of these items.

Read also: “Protective Shield RADPAD Reduces the Radiation Dose Received by Operators in the Cath Lab”.

The work “Radiation Exposure Among Scrub Technologists and Nurse Circulators During Cardiac Catheterization. The Impact of Accessory Lead Shields” (Ryan D. Madder et al.) is interesting, but deals with a fact that has been sufficiently verified. It should also be taken into account that the number of devices placed must not hinder circulation, which, at times, hast to be very fast. Additionally, instead of placing another lead shield at the side of the patient’s intravenous extension line, which may sometimes difficult extreme oblique projections, the best course of action is to restrict radiation emission while the nurse is beside the patient up until s/he finishes the task at hand and leaves the room.

Read also: “Study Confirms Lead Shields Protect Cath Lab Staff from Radiation Exposure”.

The paper “Low-Dose Exposure to Ionizing Radiation Deregulates the Brain-Specific miR-134 in Interventional Cardiologists” (Andrea Borghini et al.) brings to the table a truly current topic as regards radiation protection. The article centers around the finding of non-coding RNA molecules (microRNAs or miR), which are short chains of about 22 nucleotides (generally very stable and specific) that, by dysregulating, may transform into disease markers (in this case, for diseases induced by radiation).

Read also: “Effects of Cerebral Radiation on Interventional Cardiologists”.

miR-134 was the first to be identified as brain-specific. It acts in the development of new synapses and it is directly involved in learning and memory processes. Additionally, this microRNA is dysregulated in several types of dementia (including Alzheimer’s disease) and in tumors such as oligodendrogliomas and glioblastomas. Taking into account this evidence, an alteration in miR-134 suggests that brain damage is one of the main long-term risks for interventional cardiologists, with possible consequences such as cognitive impairment. More studies are obviously needed to confirm these facts, but there is an additional problem that I put forward here, for consideration of our readers: What should we do when these changes are detected in a young or young adult interventional professional? Should they leave their job? Should they switch careers?

However, in my opinion, the most surprising topic addressed (which is related to the subject matter of the previous article) was the finding of acute biological damage in interventional professionals, who in this case performed percutaneous repairs of abdominal aortic aneurysms. Such damage disappeared 24 hours later, according to the paper “Radiation Induced DNA Damage in Operators Performing Endovascular Aortic Repair” (El-Sayed T et al.). Its authors worked at a London hospital where a significant number of endovascular abdominal aortic aneurysm repairs are performed yearly. They showed for the first time that there were acute DNA changes in lymphocytes in operators, which disappeared after 24 hours and were not observed in surgeons performing open repairs.

Read also: “Important Study Detects Radiation-Induced DNA Damage in Operators After an Endovascular Procedure”.

On the other hand, they compared such DNA changes with those in operators whom, besides conventional radiation protection devices, also wore leg lead shielding. The latter experienced significantly less DNA changes. Furthermore, investigators took blood samples from endovascular operators and conventional surgeons, which were irradiated in vitro. Changes induced by radiation were widely dispersed, which shows extremely varied radiosensitivity among actors, something that should be applied to the general population.

Authors mention 3 clinically interesting implications (which are almost shocking and may be controversial): 1) individual dosimetry, as currently used, fails to predict the biological consequences we might experience; 2) the annual limits of professional exposure established by international organizations have been set without taking into account interpersonal variations; 3) the use of leg lead shielding is recommended for primary operators.

Some of these findings and conclusions are somewhat concerning, and these last 2 articles warranted an editorial by Dr. Charles Chambers in an issue of Circulation published a few weeks ago (2017;136:2417-9). That author concludes that, if Prof. Roentgen witnessed the current situation almost 120 years after receiving the Nobel Prize for his discovery, he would be disappointed to see that most laboratories do not follow up on patients who received high doses of radiation or on many operators, for whom there is no strict dose follow-up during their career.

Dr. Chambers recalls that, since 2011, radiation is an American College of Cardiology (ACC)/American Heart Association (AHA) Class I indication, and he recommends substituting fluoroscopy time (which is probably ineffective) with air Kerma at the interventional reference point and the dose area product in Gy cm². Finally, he emphasizes (as do we) the fact that each country, with its health authorities and cardiology societies (and, why not, SOLACI), should encourage the creation of registries that record all radiation doses ever received by patients since birth. As regards operators, he suggests the creation of databases reporting consistently all doses received, as well as orthopedic issues and other problems that may arise in relation to their career.

Thus, the objective is to make cath labs the safest environment possible, which would result in less unnecessary exposure for patients and less temporary or definitive workforce loss.

That would undoubtedly benefit us and patients greatly, but its achievement requires knowledge and understanding from health authorities, manufacturing companies, and, of course, ourselves.

Courtesy of Dr. Ariel Durán.

Specialist in Cardiology, Intensive Care, and Hemodynamics.

Associate Professor, Cardiology, Hospital de Clínicas, Montevideo School of Medicine.

Interventional Cardiologist, Montevideo Instituto de Cardiología Integral.

Consultant Cardiologist, Médica Uruguaya, Medical Assistance Corporation, Montevideo.

Academic Coordinator in Cardiology, Médica Uruguaya, Medical Assistance Corporation, Montevideo.

Fellow American College of Cardiology.

President of the SOLACI Committee on Radiation Protection. His vast number of publications on this subject matter won him the Editors award of JVIR as the Outstanding Clinical Research Paper for 2013, for the RELID study.

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