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Radiation dose from percutaneous coronary intervention (PCI) depended more on institutional radiation safety practices than most patient and procedural characteristics, a study found.

The frequency of PCI procedures with air kerma (AK) ≥5 Gy ranged from 0.0% to 10.9% across 28 hospitals enrolled in the Blue Cross Blue Shield of Michigan Cardiovascular Collaborative registry.

Independent predictors of procedural AK ≥5 Gy included BMI, dyslipidemia, diabetes, prior coronary bypass surgery, use of mechanical circulatory support, and the performing hospital, reported researchers led by Ryan Madder, MD, of Frederik Meijer Heart & Vascular Institute in Grand Rapids, Michigan, in the April 13 issue of.

Even after accounting for patient characteristics and procedural variables, the performing hospital remained a factor in procedural AK ≥5 Gy during PCI, with a median OR of 3.08 (95% CI 3.01-3.16). Only mechanical circulatory support had a higher impact on the odds of high procedural radiation (fixed OR 4.22, 95% CI 3.31-5.35).

"This observation suggests ... that the institution at which any given PCI is performed is a major factor in determining the likelihood that a patient receives a high radiation dose during PCI. Taken collectively, the findings of this study indicate an opportunity for quality improvement in radiation safety practices across institutions performing PCI," the authors concluded.

Hospitals with more radiation in PCI were associated with higher radiation dose of all other cases, they added.

"This variability in radiation dosing across hospitals is alarming and is a wake-up call for hospitals to address training and adoption of proven efforts to as a quality improvement initiative," commented John Lopez, MD, and Amir Darki, MD, MPH, both of Loyola University Medical Center in Maywood, Illinois.

"Although improvements in operator techniques to limit radiation and manufacturers' efforts to create low-dose fluoroscopic systems have improved safety, these efforts are likely counterbalanced by the unremitting march toward longer and more complex catheterization laboratory procedures, including chronic total occlusion coronary intervention and the emergence of prolonged structural heart disease procedures," they wrote in an accompanying editorial.

Indeed, in the study, the higher-radiation procedures were more commonly performed in conjunction with other procedures at the time of PCI, and used more intra-aortic balloon pumps and other mechanical circulatory support devices, compared with cases where AK was less than 5 Gy.

Signs point to higher-radiation PCIs involving more complex and sicker patients, according to Madder's team.

For this study, the investigators analyzed radiation doses recorded from 36,201 PCIs performed from 2016 through 2018 in Michigan.

Procedural AK ≥5 Gy was recorded in 4.1% of cases, ≥10 Gy in 0.5%, and ≥15 Gy in 0.3%.

"Most operators are familiar with deterministic damage to skin tissue, where tissue injury begins at 2 Gy with erythema but can progress at doses >5 Gy to epilation, hair loss, and dermal atrophy, with doses exceeding 15 Gy resulting in the most serious consequences of tissue desquamation and necrosis, which often requires skin grafting," noted Lopez and Darki.

"It is for this reason that doses exceeding 15 Gy are considered sentinel events by The Joint Commission," they wrote.

Study investigators cautioned that procedural AK is a measure of radiation energy delivered to air during PCI, not a direct count of radiation delivered to patients.

The study was also limited by the potential for unmeasured confounding given its observational nature. Moreover, there was incomplete reporting of radiation, as only 73.7% of PCIs had corresponding AK values in the registry.

"Although some might suggest that the findings outlined by Madder et al. should result in public reporting of institutional PCI radiation dosing, this would be a mistake because, as was evident in this analysis, it would be difficult to correct for procedural complexity, potentially resulting in a chilling effect on efforts to treat complex lesion and patient subsets," Lopez and Darki wrote.

"Instead, the focus should remain local and within institutions, with use of tools such as the National Cardiovascular Data Registry CathPCI Registry, which includes AK dosing data, allowing an institution to compare its results with those of other institutions," they argued.

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