_{AUTHOR: Greg Guillory}

The selection of drug-eluting stents (DES) for percutaneous coronary intervention (PCI) involves balancing efficacy against safety. The SORT OUT XI randomised trial aimed to compare a newer-generation biolimus-eluting stent with a contemporary dual-therapy sirolimus-eluting stent in a real-world patient population, providing crucial head-to-head evidence.¹

SORT OUT XI was a prospective, randomised, noninferiority trial conducted across three major heart centres in Denmark.² The study enrolled 3,136 ‘all-comer’ patients undergoing PCI for any clinical indication. Patients were randomised on a 1:1 basis to receive either the biolimus A9–eluting Biomatrix Alpha stent (BES), which has thin struts and a biodegradable polymer, or the dual-therapy sirolimus-eluting Combo stent (DTS).

The primary endpoint was target lesion failure (TLF) at 1-year follow-up, a composite of cardiac death, target lesion myocardial infarction (MI), or clinically indicated target lesion revascularisation. The trial was designed to test for noninferiority of the BES, with a pre-specified noninferiority margin of 2.1%.

At 1-year follow-up, the primary endpoint of TLF occurred in 65 patients (4.2%) in the BES group and 82 patients (5.2%) in the DTS group. The absolute risk difference was -1.07% (upper limit of 1-sided 90% CI: 0.21%), which met the criteria for noninferiority (P for noninferiority = 0.00002). The incidence rate ratio (IRR) for TLF was 0.79 (95% CI: 0.57–1.09; P=0.15), indicating no significant difference in superiority.

Analysis of the individual components of the primary endpoint showed no significant differences for cardiac death (1.1% for BES vs 1.9% for DTS; IRR: 0.60; P=0.08) or target lesion MI (2.3% for BES vs 2.1% for DTS; IRR: 1.09; P=0.73).

However, a significant safety concern emerged regarding stent thrombosis. The rate of definite stent thrombosis was significantly higher in the BES group, occurring in 21 patients (1.3%) compared to 9 patients (0.6%) in the DTS group (IRR: 2.33; 95% CI: 1.07–5.11; P=0.034).

The SORT OUT XI trial demonstrates that the biolimus-eluting Biomatrix Alpha stent is noninferior to the dual-therapy sirolimus-eluting Combo stent for the primary efficacy endpoint of TLF at 1 year. However, this finding is overshadowed by a concerning safety signal. The more than twofold increased risk of definite stent thrombosis associated with the BES is a critical finding that will likely influence clinical decision-making. As the study authors concluded, “BES was noninferior to DTS at 1-year follow-up regarding the primary endpoint of TLF. However, BES was associated with significantly increased risk of definite stent thrombosis.”¹ This outcome highlights the importance of evaluating both efficacy and safety endpoints in stent trials, as noninferiority in one domain does not guarantee equivalent safety.

References

1. Eftekhari A, Jensen LO, Veien K, et al. Biolimus-eluting biomatrix stent vs a dual-therapy sirolimus-eluting stent in PCI: the SORT OUT XI randomized trial. J Am Coll Cardiol. 2025;86:106–15. https://doi.org/10.1016/j.jacc.2025.05.012

2. Eftekhari A, Christiansen EH, Lassen JF, et al. Randomized comparison of the combined sirolimus eluting and endothelial progenitor cell combo stent vs biolimus eluting absorbable polymer coated biomatrix alpha stent in patients undergoing percutaneous coronary intervention: rationale and study design. Am Heart J. 2025;283:37–42. https://doi.org/10.1016/j.ahj.2025.01.012

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