Which parameters are important before attempting chronic total occlusions recanalization?

Even in the era of advanced skills of operators of chronic total occlusions (CTO) combined with new sophisticated technologies and devices, percutaneous coronary interventions (PCI) of CTO remain challenging. These procedures are technically complex. Thus, the risk of failure and complications is very dependent on technical skills of the operator and vary from study to study. There are also some controversies, fortunately year by year less frequent, mainly due to the sharing of knowledge in the cardiology community, creating appropriate indications for CTO revascularization [1, 2]. Finally, there are still some uncertainties regarding benefits of the CTO procedure, but the growing number of studies reporting good procedural, functional and, most importantly, a positive effect on long-term outcome, shifts the balance toward benefits. Despite the lack of randomized trials, in a recent meta-analysis of 25 studies published from 1990 to 2014 with 28,486 patients (29,315 CTO PCI procedures) with a mean follow-up of 3.11 years (range 6 months to 12 years) Christakopoulos from the E. Brilakis group elegantly showed that successful CTO PCI compared with failed procedures are associated with a lower risk of death, stroke and coronary artery bypass grafting and less recurrent angina pectoris [3].
When dealing with CTO we should take into account two very important aspects – the technical aspect and the impact of prognosis of the patients. If the qualification for the procedure is proper, according to the angiographic point of view, the chance of success is greater. Moreover, if the patient has a proper clinical indication (i.e. a sufficient amount of ischemia or viability) both aspects may lead to a better outcome during the procedure and follow-up.
In the previous issue of Advances in Interventional Cardiology, Baykan et al. tried to find factors which adversely influence the success rate of CTO PCI [4]. After analysis of 173 procedures they concluded that bridge collaterals, severe calcification and tortuosity, tandem/multiple occlusions were independent predictors of unsuccessful CTO revascularization, while the presence of micro-channels was a predictor of success. The Turkish authors reported a 83.2% success rate, acceptable but slightly lower than that presented by highly specialized CTO centers. Some of the predictors of success are similar to variables used in the J-CTO score (calcification, tortuosity, tandem and multiple occlusions may...


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