Predictors of Excess Patient Radiation Exposure During Chronic Total Occlusion Coronary Intervention: Insights From a Contemporary Multicentre Registry

Background: High patient radiation dose during chronic total occlusion (CTO) percutaneous coronary intervention (PCI) might lead to procedural failure and radiation skin injury. Methods: We examined the association between several clinical and angiographic variables on patient air kerma (AK) radiation dose among 748 consecutive CTO PCIs performed at 9 experienced US centres between May 2012 and May 2015. Results: The mean age was 65 +/- 10 years, 87% of patients were men, and 35% had previous coronary artery bypass graft surgery (CABG). Technical and procedural success was 92% and 90%, respectively. The median patient AK dose was 3.40 (interquartile range, 2.00-5.40) Gy and 34% of the patients received > 4.8 Gy (high radiation exposure). In univariable analysis male sex (P = 0.016), high body mass index (P < 0.001), history of hyperlipidemia (P = 0.023), previous CABG (P < 0.001), moderate or severe calcification (P < 0.001), tortuosity (P < 0.001), proximal cap ambiguity (P < 0.001), distal cap at a bifurcation (P = 0.006), longer CTO occlusion length (P < 0.001), blunt/ no blunt stump (P < 0.001), and centre (P < 0.001) were associated with higher patient AK dose. In multivariable analysis high body mass index (P < 0.001), previous CABG (P = 0.005), moderate or severe calcification (P = 0.005), longer CTO occlusion length (P < 0.001), and centre (P < 0.001) were independently associated with higher patient AK dose. Conclusions: Approximately 1 in 3 patients who undergo CTO PCI receive high AK radiation dose (> 4.8 Gy). Several baseline clinical and angiographic characteristics can help predict the likelihood of high radiation dose and assist with intensifying efforts to reduce radiation exposure for the patient and the operator.