CASTLE RCT Compares Image-Guided PCI With Biodegradable SES Versus Durable EES

May 18, 2021—PCR announced that findings from the all-comers CASTLE study were presented at the virtual EuroPCR 2021 conference held May 18-20. CASTLE was designed to assess the role of imaging-guided percutaneous cardiac intervention (PCI) in the clinical outcomes difference of ultra-thin strut (60 µm) biodegradable polymer sirolimus-eluting stents (BP-SES; Orsiro, Biotronik) compared to a durable polymer everolimus-eluting stents (DP-EES; Xience, Abbott).

According to PCR, previous clinical trials suggested that BP-SES may be associated with lower target lesion failure (TLF) when compared to DP-EES. However, the possible underlying mechanisms remain unclear. The background of the investigation is that although it is thought that ultra-thin BP-SES may provide potential advantages such as reduced vessel inflammation and thrombogenicity versus DP-EES, randomized clinical trials have provided mixed results. The BIOFLOW-V and BIOSTEMI trials showed a lower risk of TLF with BP-SES when compared to DP-EES. Meanwhile, the BIOSCIENCE trial showed neutral results. One of the possible explanations of these contradictory findings is the use of intracoronary imaging, noted PCR.

The CASTLE investigators hypothesized the actual difference in clinical outcomes between BP-SES and DP-EES might be clarified under imaging-guided PCI.

PCR stated that the CASTLE study is an investigator-initiated, multicenter, single-blinded, randomized, noninferiority clinical trial executed in 69 centers in Japan. The population was composed of patients with acute and chronic coronary syndromes. Patients were randomized in a 1:1 ratio to image-guided PCI (intravascular ultrasound or optical coherence tomography) with BP-SES (intervention group) or DP-EES (control group).

The primary outcome was TLF (cardiovascular death, target vessel myocardial infarction, and clinically driven target lesion revascularization) at 12-month follow-up. An independent clinical event committee evaluated angiographies and clinical events. The prespecified margin for noninferiority was 3.3%.

As summarized in the PCR announcement, the CASTLE investigators reported an interim analysis with approximately 70% of the follow-up.

Between May 2019 and March 2020, the study investigators randomized 1,440 patients: BP-SES, n = 722; DP-EES, n = 718. The 12-month follow-up was completed in 69.1% in the BP-SES group and 68.6% in the DP-EES. There were no significant differences between groups in terms of clinical and procedural characteristics. The trial included mainly chronic coronary syndromes (85%), stent diameter ≤ 3 mm (66%), and imaging guidance was performed in at least 97.5% of the patients.

At 30-day follow-up, there was no difference in TLF between DP-SES and DP-EES (5.0% vs 4.9%) or its components. For the primary endpoint, there was no difference in TLF between DP-SES and DP-EES (hazard ratio, 0.59; 95% CI, 0.26-1.36) at 12-month follow-up.

In this interim analysis, the data suggest that BP-SES and DP-EES may have similar clinical outcomes when PCI is performed under intracoronary imaging guidance. However, the complete follow-up must be performed before assessing any potential difference between these two devices, cautioned the investigators in the PCR press release.