PCI for Chronic Total Occlusions: Predictor of Technical Failure

Study Questions:

What is the 10-year experience of a single operator dedicated to chronic total occlusion (CTO), and the predictors of technical failure?


One thousand nineteen patients with CTO underwent 1,073 CTO procedures performed by a single CTO dedicated operator. The study population was subdivided into two groups by time period: period 1 (January 2005 to December 2009, n = 378) and period 2 (January 2010 to December 2014, n = 641). Observations were randomly assigned to a derivation set and a validation set (in a 2:1 ratio). A prediction score was established by assigning points for each independent predictor of technical failure in the derivation set according to the beta coefficient and summing all points accrued.


Lesions attempted in period 2 were more complex in comparison with those in period 1. Compared with period 1, both technical and clinical success rates significantly improved (from 87.8% to 94.4% [p = 0.001] and from 77.6% to 89.9% [p < 0.001], respectively). A prediction score for technical failure including age 75 years (1 point), ostial location (1 point), and collateral filling Rentrop grade <2 (2 points) was established, stratifying procedures into four difficulty groups: easy (0), intermediate (1), difficult (2), and very difficult (3 or 4), with decreasing technical success rates. In derivation and validation sets, areas under the curve were comparable (0.728 and 0.772, respectively).


The authors concluded that with growing expertise, the success rate for CTO percutaneous coronary intervention has increased despite increasing complexity of attempted lesions.


This study reports that despite the increased complexity of CTO lesions attempted, both technical and clinical success rates have gradually improved. Furthermore, although the J-CTO score influenced procedural details, its utility in predicting technical success was limited, but a prediction model (ORA score) including age, ostial location, and collateral filling was able to predict technical failure. Further validation of the ORA score in a large multicenter cohort of patients is indicated to define its utility in CTO interventions.

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