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The management of de novo ostial left circumflex (LCx) coronary artery lesions remains one of the most technically challenging aspects of percutaneous coronary intervention (PCI). These lesions are often located at the bifurcation with the left main coronary artery and are prone to incomplete coverage and high restenosis rates when treated with drug-eluting stents (DES). Furthermore, deferring treatment in this area has been associated with increased rates of adverse cardiovascular events. Although drug-coated balloons (DCBs) have emerged as a promising option in side branch and bifurcation lesions, their efficacy and safety profile in the specific setting of ostial LCx lesions had not been previously evaluated in a dedicated clinical study. The DCB-CIRCO registry was developed to address this important gap in evidence by comparing DCBs with DES in a real-world population.

The DCB-CIRCO registry aimed to compare DCBs and DES in the treatment of de novo osteal LCx lesions. The primary endpoint was the two-year rate of target lesion failure (TLF), defined as a composite of clinically driven target lesion revascularization, cardiac death, or target vessel myocardial infarction. Key secondary endpoints included target vessel failure (TVF) and procedural metrics such as fluoroscopy time, contrast use, and periprocedural complications.

This registry was an observational, retrospective, study conducted across eight high-volume international centers with expertise in DCB-based PCI. The study included consecutive patients who underwent PCI with DCB for ostial LCx lesions between 2018 and 2023. Eligible lesions were classified according to SYNTAX segment 11, including both isolated LCx ostial lesions (Medina 0,0,1) and distal left main bifurcations involving the LCx (Medina 1,1,1; 1,0,1; or 0,1,1). The comparator group consisted of a historical cohort of patients treated with DES for ostial LCx lesions at three Italian centers between 2012 and 2021. To adjust for baseline differences, 1:1 propensity score matching (PSM) was performed using clinical and anatomical variables including age, sex, cardiovascular risk factors, previous revascularization, lesion characteristics, and the presence of multivessel disease. Clinical outcomes were assessed using the Kaplan-Meier method.

A total of 152 patients were treated with DCB and 351 with DES. After propensity score matching, 126 patients remained in each group. The baseline characteristics were well balanced following matching, with a median age of 70 years and a predominance of multivessel coronary artery disease. Lesion complexity was notable, and the use of advanced lesion preparation tools such as intravascular lithotripsy, scoring balloons, and intravascular imaging was more frequent in the DCB arm. The primary endpoint, TLF at two years, occurred in 19.8% of patients treated with DCB versus 21.3% in the DES group. This difference was not statistically significant (HR: 1.12; 95% CI: 0.60–2.08; p=0.718), indicating that DCB was non-inferior to DES in terms of lesion-level clinical outcomes. Subgroup analysis revealed consistent results across patients with and without diabetes, as well as those with different Medina classifications and DCB drug types (paclitaxel vs. sirolimus). The key secondary endpoint, TVF, occurred in 23.3% of the DCB group compared with 31.1% in the DES group (HR: 0.75; 95% CI: 0.43–1.30; p=0.302). Although this numerical difference favored DCB, it did not reach statistical significance. However, the trend suggests that vessel-level outcomes may be improved with DCB therapy, especially when considering the complexity of bifurcation anatomy. Importantly, the DCB strategy was associated with significantly shorter fluoroscopy times and lower total contrast use, which may have implications for procedural efficiency and safety, particularly in patients with renal dysfunction. Additionally, DCB use facilitated simplified procedural strategies, avoiding complex dual-stenting techniques in many cases.

The DCB-CIRCO registry is the first dedicated study to evaluate the clinical performance of DCBs versus DES in the treatment of ostial LCx lesions. The findings from this real-world, multicenter experience suggest that the use of DCBs is both safe and effective, providing comparable mid-term clinical outcomes to DES while offering procedural advantages such as reduced fluoroscopy exposure and lower contrast utilization. These results were consistent across key clinical and anatomical subgroups, including those with diabetes and complex bifurcation anatomy. Although limited by its retrospective and non-randomized design, the study provides important evidence supporting the use of DCB in a setting where DES implantation may be technically challenging. In the absence of randomized trial data, the DCB-CIRCO registry contributes valuable insights that may help guide treatment decisions for complex left coronary bifurcations and support the broader adoption of DCBs in appropriate clinical scenarios.

This registry provides valuable early evidence supporting the use of DCBs as a feasible DES for ostial LCx lesions. The comparable outcomes in terms of lesion and vessel failure, along with procedural advantages such as shorter fluoroscopy time and reduced contrast usage, are promising—especially in high-risk or anatomically complex cases. However, several limitations should be acknowledged. The retrospective design and use of a historical control group introduce potential bias, particularly given the different enrollment periods. The absence of a core lab or event adjudication also limits the robustness of outcome assessment. Furthermore, the two-year follow-up may not fully capture late adverse events, especially when comparing a transient device (DCB) with a permanent implant (DES). While further validation is needed, this study offers an important perspective within the ongoing shift toward more individualized and less device-dependent treatment paradigms in complex coronary interventions.