Prolonged radiation exposure from fluoroscopy is associated with an increased risk to patients and physician alike. Prolonged skin exposure, the “dose effect”, is driven by the “absorbed” radiation dose to the patient. Although nearly 99% of the delivered dose is lost due to scatter, and only 1% actually penetrates the patient, the skin is still exposed to this higher dose. The rate of complications is directly related to this exposure. Both deterministic and stochastic effects of radiation on the body, though rare, have been reported and may range from mild radiodermatitis to radiation-induced skin cancer.6 High levels of fluoroscopy begin to result at time of exposure over 50 minutes, depending on the patient’s size and body habitus. Increased fluoroscopy time and radiation exposure also have been associated with more complex coronary interventions and can be quite high, with mean dose-area products (DAPs) ranging from 20.3 Gy cm2 to 174.0 Gy cm2.14 The International Commission on Radiological Protection (ICRP) recommends that the patient be notified and a skin exam performed 10–14 days postprocedure if the ESD exceeds 3.0 Gy. Also, the patient should be informed of the possibility of radiation-induced skin damage before a complex procedure.15 Early transient erythema, permanent epilation, and delayed dermal necrosis can occur at ESDs of 2 Gy, 7 Gy, and 12 Gy, respectively.15 Beyond these obvious skin effects, other complications of extended fluoroscopy times have not been well documented.
The current manuscript by Nikolsky et al16 in the Journal of Invasive Cardiology, evaluated patients with higher fluoroscopy times undergoing percutaneous coronary interventions (PCI) that fell outside the 75th percentile of fluoroscopy time in their ongoing database. The authors sought to correlate fluoroscopic times (a surrogate for radiation exposure) with short-term patient prognosis and resource utilization. As one would expect, these patients were more complicated as evidenced by being older, having a higher incidence of prior coronary artery bypass grafting (CABG) surgery, presence of peripheral arterial disease, unstable angina, more complex coronary anatomy, renal insufficiency and lower baseline left ventricular ejection fractions. Given these higher-risk patient populations, it is not surprising that events on in-hospital mortality and morbidity and increased resource utilization would likewise be higher. What is intriguing is that the effects and risks are highest in patients who undergo only 23 minutes or greater of fluoroscopy.
Not surprisingly, the authors described an association between longer fluoroscopy times and complex anatomy including vein and arterial grafts and right coronary artery lesions. Complex lesion characteristics such as lesion length, bifurcation lesions, and excessive calcifications in addition to lower TIMI flow grades were also associated with longer fluoroscopy times. This is not surprising, as longer fluoroscopy times likely represent a surrogate marker for procedure complexity. Procedure complexity would also likely be associated with contrast media load; however, the authors found that even though contrast media load and fluoroscopy times were correlated, contrast load had no relationship to in-hospital outcomes. This suggests that fluoroscopy times, not contrast load, may represent a more reliable and independent indicator of short-term outcomes.
Some important limitations must be considered from this manuscript. First, the patients without complex disease who still had high fluoroscopy times were not mentioned, and we do not know if they also had higher complications or events compared to those without this increased exposure rate. Secondly, despite the higher radiation exposure, there were no reported skin effects in the patients studied. Despite these limitations, this manuscript has corroborated what most interventionalists believe: the more complex the patients become, the longer and more protracted cases can be. What is more important, however, is that this patient population is likely to have higher morbidity and mortality after revascularization, which directly translates to increased medical and hospital costs and resource utilization. Having this knowledge will help many endovascular specialists to properly advise patients of their risks prior to any intervention and to plan ahead in anticipation of increased morbidity in this at-risk patient population.
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- Suzuki S, Shigeru F, Kohtake H, et al. Radiation exposure to patient’s skin during percutaneous coronary intervention for various lesions, including chronic total occlusion. Circ J 2006;70:44–48.
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- Nikolsky E, Pucelikova T, Mehran R, et al. An evaluation of fluoroscopy time and correlation with outcomes after percutaneous coronary intervention. J Invasive Cardiol 2007;19:208–213.