J Transcat Intervent.2019;27:eA201828.
Chronic total occlusion: conqueringthe last frontier of percutaneous coronary intervention
Historically, chronic total occlusions (CTO) comprise the subgroup of the most difficult lesions to be treated by percutaneous techniques. CTO is one of the most important predictors of the need for coronary artery bypass grafting, of incomplete revascularization, and low success rates in attempts for percutaneous recanalization. In addition, CTO has been considered one of the factors associated with higher mortality rates in ST-segment or non-ST-segment elevation myocardial infarction patients. Many obstacles are faced when trying to perform target-vessel recanalization in this subgroup of patients; however many of these historic barriers have been overcome by advancement of technology and development of new devices and materials, as well as new antegrade dissection and reentry techniques, greater adoption of retrograde techniques and, finally, by using hybrid algorithm. Such factors have raised the procedure success in this type of lesion to rates above 90%.
CTO accounts to approximately 15 to 20% of cases found in coronary angiographies, with a high referral rate for coronary artery bypass grafting, of which less than 5% are attempted percutaneously. Evaluating retrospective studies and registries, we noticed – in selected patients – there is evidence of treatment aiming to alleviate symptoms, improve quality of life, improve left ventricular function, reduce mortality, improve ischemic burden after revascularization, and increase tolerance to future ischemic events. The randomized study Euro CTO was published in 2018, and definitively demonstrated relief of symptoms and better quality of life in this group of patients. In the same year, the DECISION study was published with negative results, showing no differences between optimized medical treatment and recanalization of CTO. Nevertheless, the investigation methodology was criticized for lack of sufficient statistical power and large amount of crossing over (patients of the medical treatment arm migrated to the intervention group). Moreover, the study was prematurely interrupted due to difficult patient recruitment – the initial objective was to enroll 1,284 patients but only 834 were included.