Long-term Outcomes of Percutaneous Coronary Intervention for In-Stent Chronic Total Occlusion
Percutaneous coronary intervention (PCI) for in-stent chronic total occlusion (IS-CTO) represents one of the most challenging subsets of coronary interventions. IS-CTO accounts for 5% to 25% of all chronic total occlusions (CTOs) and is associated with significant technical difficulties due to the presence of pre-existing stent structures. Despite advancements in equipment and techniques, which have improved the technical success rate of IS-CTO PCI to 86%, the long-term outcomes of these procedures remain unclear. This study aimed to investigate the long-term outcomes of PCI for IS-CTO, focusing on major adverse cardiac events (MACE), recurrent angina, and the impact of dual antiplatelet therapy (DAPT) on clinical outcomes.
The study retrospectively analyzed 474 patients who underwent PCI for IS-CTO at two cardiac centers in China between 2015 and 2018. Patients were divided into two groups based on the success or failure of the PCI procedure. The primary endpoint was the occurrence of MACE, which included recurrent angina pectoris (RAP), target-vessel myocardial infarction (MI), heart failure, cardiac death, or ischemia-driven target-vessel revascularization (TVR). The median follow-up period was 30 months, with an interquartile range of 17 to 42 months.
The results showed that 367 patients (77.4%) were successfully treated with IS-CTO PCI, while 107 patients (22.6%) experienced failed recanalization. At the 30-month follow-up, there were no significant differences between the successful and failed PCI groups in terms of cardiac death (0.9% vs. 2.7%), RAP (40.8% vs. 40.0%), heart failure (6.1% vs. 2.7%), target-vessel MI (1.5% vs. 2.7%), or overall MACE (44.2% vs. 45.3%). However, the successful PCI group demonstrated improved angina symptoms and a lower incidence of MACE in the first and second years post-procedure compared to the failed PCI group. Specifically, 80.4% of patients in the successful PCI group were free of angina in the first year, compared to 60% in the failed PCI group. By the second year, these figures were 73.3% and 60.0%, respectively. Additionally, the successful PCI group had a lower incidence of MACE in the first (20.2% vs. 40.0%) and second years (27.9% vs. 41.3%).
The study also highlighted the high rates of reocclusion and TVR in the successful IS-CTO PCI group. At the 30-month follow-up, the reocclusion rate was 28.5%, and the TVR rate was 26.1%. Multivariable Cox regression analysis identified long-term DAPT (greater than 18 months) as an independent predictor of decreased risk of TVR and MACE. Patients who received long-term DAPT had a significantly lower risk of TVR (HR: 2.682; 95% CI: 1.295–5.578) and MACE not driven by TVR (HR: 1.898; 95% CI: 1.036–3.479). Other predictors of restenosis/reocclusion included smaller vessel diameter, female sex, and higher body mass index (BMI).
The findings of this study underscore the complexity and challenges associated with IS-CTO PCI. While the procedure can provide immediate relief from angina and reduce the need for coronary artery bypass grafting (CABG) in the short term, the long-term outcomes are less favorable. The high rates of reocclusion and TVR suggest that biological factors contributing to the initial in-stent occlusion may persist and lead to recurrent issues after PCI. The study also emphasizes the importance of long-term DAPT in reducing the risk of adverse events in IS-CTO patients.
The baseline characteristics of the study population revealed that the majority of IS-CTOs were located in the right coronary artery (RCA, 43.9%), followed by the left anterior descending artery (LAD, 35.2%) and the left circumflex artery (LCX, 17.4%). The failed PCI group had a higher proportion of IS-CTOs in the RCA (60.7% vs. 39.0%) and fewer in the LAD (22.4% vs. 39.0%) compared to the successful PCI group. The failed PCI group also exhibited longer occlusion lengths (45.54 ± 26.44 mm vs. 17.81 ± 13.27 mm) and higher rates of complex lesion characteristics, such as ostial CTO, proximal bifurcation, moderate or severe tortuosity, proximal bending, under expansion, and poor distal target.
Procedural characteristics showed that the overall success rate of IS-CTO PCI was 77.4%. The most common crossing strategy was antegrade wire escalation (96.0%), while the retrograde approach was used in only 4.0% of cases. Intravascular ultrasound (IVUS) was utilized in 6.8% of successful PCI cases, primarily due to cost and time constraints. Major procedural complications occurred in 12.1% of cases, including side branch loss, low/no flow, perforation, and dissection. However, there were no deaths, strokes, stent thrombosis, or emergent TVR during hospitalization.
The clinical outcomes at follow-up revealed that 411 patients (86.7%) were available for analysis. In the failed PCI group, 10 patients underwent CABG, and 7 patients underwent a second PCI within one month, which was successful and thus transferred to the successful PCI group. The remaining 75 patients in the failed PCI group received standard medical therapy (MT), including aspirin, clopidogrel/ticagrelor, ACE inhibitors, beta-blockers, and statins. There were no significant differences in medication use between the successful and failed PCI groups at the 30-month follow-up.
Kaplan-Meier analysis of MACE-free survival curves showed that the curves for the successful and failed PCI groups crossed at 36 months, with no significant difference in MACE rates (HR: 1.052; 95% CI: 0.717–1.543). However, the successful PCI group had a lower incidence of MACE in the first and second years post-procedure. The study also found that CABG was associated with a lower incidence of MACE (13.6%) compared to successful PCI (44.2%) and failed PCI (45.3%).
The study’s discussion highlights the high incidence of MACE and reocclusion in the successful IS-CTO PCI group, despite the initial technical success. The authors suggest that the biological factors contributing to the initial in-stent occlusion may persist and lead to recurrent issues after PCI. The study also emphasizes the importance of long-term DAPT in reducing the risk of adverse events in IS-CTO patients. Additionally, the authors recommend CABG as an initial treatment option for IS-CTO patients with significant concomitant left main disease, multivessel disease, or complex coronary artery disease.
In conclusion, this study provides valuable insights into the long-term outcomes of PCI for IS-CTO. While successful PCI can improve angina symptoms and reduce the need for CABG in the short term, the long-term outcomes are less favorable, with high rates of reocclusion and TVR. Long-term DAPT is essential for reducing the risk of adverse events in IS-CTO patients. The findings of this study have important implications for clinical decision-making and the management of IS-CTO patients.
doi.org/10.1097/CM9.0000000000001289
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