Modification Procedures for Chronic Total Occlusion Percutaneous Coronary Intervention: Insights From the PROGRESS-CTO Registry

Background: CTO-ARC (Chronic Total Occlusion Academic Research Consortium) defines CTO modification procedures (previously called investment procedures) as intentional balloon dilatation (diameter ≥ 2.0 mm) of the entire CTO, including the proximal and distal caps and the CTO body. Aims: The aim of this study is to compare the outcomes of repeat CTO PCI between patients who underwent lesion modification during the initial failed procedure and those who did not. Methods: We analyzed the association of CTO modification with the baseline clinical and angiographic characteristics and outcomes of 2829 patients, with a total of 2869 CTOs who underwent CTO percutaneous coronary intervention (PCI) after a previously failed attempt. Results: CTO modification was performed in 600 of 2869 CTOs (20.9%) that underwent a repeat PCI attempt. CTOs that underwent modification had a higher prevalence of blunt/no stump (63.9% vs. 54.5%, p < 0.001), moderate/severe calcification (59.4% vs. 48.5%, p < 0.001), and moderate/severe proximal tortuosity (43.6% vs. 30.4%, p < 0.001). They also had longer length (38 vs. 31 mm, p < 0.001) and higher J-CTO (3.69 vs. 3.21, p < 0.001) score. There was no statistically significant difference in technical (84.1% vs. 85.4%, p = 0.478) or procedural (82.7% vs. 84.2%, p = 0.403) success or major adverse cardiac events (MACE, 1.7% vs. 1.8%, p = 1.0) between the modification and no modification groups. Similarly, among patients who underwent CTO modification, there were no significant differences in outcomes between early (< 60 days) and late (≥ 60 days) reattempts after the initial failure. Technical success was significantly higher after subintimal tracking and re-entry (STAR) than subintimal plaque modification (SPM) (82.5% vs. 60.0%, p = 0.028). Conclusions: CTO modification procedures were performed in approximately one of five CTO PCIs during the initial failed procedure. During reattempt CTO PCI, despite higher lesion complexity, CTO modification was associated with similar technical and procedural success and MACE compared to patients undergoing reattempt CTO PCI without prior CTO modification. Among modification techniques, STAR was associated with higher technical and procedural success than SPM.