Survivals of Angiography-Guided Percutaneous Coronary Intervention and Proportion of Intracoronary Imaging at Population Level: The Imaging Paradox

BACKGROUND: There is a significant disparity between randomized controlled trials and observational studies with respect to any mortality benefit with intracoronary imaging during the percutaneous coronary intervention (PCI). This raises a suspicion that the imaging paradox, in which some operators may become over reliant on imaging and less proficient with angiography-guided PCI, might exist. METHOD: This was a retrospective cohort study from 14 hospitals under the Hospital Authority of Hong Kong between January 1, 2010 and December 31, 2017. Participants were patients who underwent first-ever PCI. The association between mortality risks of patients undergoing angiography-guided PCI and three tertiles (low, medium, and high) of the proportion of PCI done under intracoronary imaging guidance at a population level (background imaging rate), were evaluated after confounder adjustment by multivariable logistic regression. RESULTS: In an adjusted analysis of 11,816 patients undergoing angiography-guided PCI, the risks of all-cause mortality for those were higher in the high-tertile group compared with the low-tertile group (OR, 1.45, 95% CI, 1.10–1.92, P = 0.008), the risks of cardiovascular mortality were higher in the high-tertile group compared with the low-tertile group (OR, 1.51, 95% CI, 1.08–2.13, P = 0.017). The results were consistent with multiple sensitivity analyses. Threshold analysis suggested that the mortality risks of angiography-guided PCI were increased when the proportion of imaging-guided PCI exceeded approximately 50%. CONCLUSIONS: The risks of the all-cause mortality and cardiovascular mortality were higher for patients undergoing angiography-guided PCI in practices with a higher background imaging rate.