Author + information
- Lorenzo Azzalini, MD, PhD, MSc∗ (, )
- Mauro Carlino, MD,
- Emmanouil S. Brilakis, MD, PhD and
- Antonio Colombo, MD
- ↵∗Interventional Cardiology Division, San Raffaele Hospital, San Raffaele Scientific Institute, Via Olgettina 60, Milan 20132, Italy
We read with great interest the article by Lee et al. (1), who found no long-term survival benefit of successful chronic total occlusion (CTO) percutaneous coronary intervention (PCI) in their well-performed single-center cohort study. Several observations need to be made.
The incidence of prior coronary artery bypass graft in their population was 2.8%, ejection fraction was mostly normal (only 3.8% of patients had values <40%), mean CTO length was <20 mm, and retrograde PCI was successful in only 8.5%. Although the Japanese-CTO (J-CTO) score was not calculated, these data indicate that the population treated by Lee et al. is quite selected. Additionally, because patient inclusion spanned 11 years (2003 to 2014), the techniques used in this study are not representative of contemporary CTO PCI based on the “hybrid algorithm.” For example, in the all-comer PROGRESS-CTO (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention) registry (2), mean occlusion length was 37 ± 25 mm, mean J-CTO score among successful versus failed CTO PCIs was 2.5 ± 1.2 versus 3.3 ± 1.0, and final successful crossing strategy was the retrograde approach in 28% of cases. Therefore, Lee et al. (1) might have selected a low-risk CTO population, which might explain why they found no association between successful revascularization and survival.
Another explanation might stem from the fact that “almost complete” revascularization (all lesions excluding the CTO) was achieved in 71% of unsuccessful CTO PCI patients. Additionally, coronary artery bypass graft was performed in 17% of these patients during follow-up. This can further confound the analyses, since the failed CTO PCI group actually included a relevant number of successfully (and completely) revascularized patients. Complete and “reasonably incomplete” revascularization has been associated with improved survival (3). Further speculations are hampered by the lack of assessment of the SYNTAX(Synergy Between PCI With Taxus and Cardiac Surgery) and residual SYNTAX score in the study by Lee et al. (1), as well as the fact that they did not provide a definition of complete revascularization.
Finally, their results contrast with those of much larger multicenter registries, which observed improved survival when successful CTO revascularization is achieved. George et al. (4) studied 13,443 patients who underwent CTO PCI and found that successful PCI was associated with improved survival after a median follow-up of 2.65 years.
The final answer to the neverending debate about the possible survival benefit of CTO PCI will not likely come from observational studies. Well-designed and adequately powered randomized trials are eagerly awaited.
Please note: Dr. Brilakis has received consulting/speaker honoraria from Abbott Vascular, Asahi, Boston Scientific, Elsevier, Somahlution, St. Jude Medical, GE Healthcare, and Terumo; has received research grant support from InfraRedx and Boston Scientific; and has a spouse that is an employee of Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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