Sirolimus-coated versus paclitaxel-coated balloons for bifurcated coronary lesions in the side branch: the SPACIOUS trial

The optimal strategy to treat coronary bifurcation lesions (CBL) has been a long-debated topic. The combination of a stent in the main vessel (MV) and a drug-coated balloon (DCB) in the side branch (SB) seems promising, but the evidence is limited. This study aims to investigate a novel sirolimus-coated balloon in the treatment of non-left main CBL compared with a paclitaxel-coated balloon. The SPACIOUS trial is a prospective, non-inferiority, multicentre trial. A total of 230 patients were randomised to the sirolimus DCB or the paclitaxel DCB group in a 1:1 ratio. Angiographic and clinical follow-ups were planned at 9 months and 1 year, respectively. The primary endpoint was diameter stenosis (DS) in the SB at 9 months. At 9 months, DS in the sirolimus group was 30.5±16.1% compared with 33.5±16.2% in the paclitaxel group (difference -2.94%; 95% confidence interval: -7.62% to 1.74%; p for non-inferiority<0.01). The incidence of binary restenosis was significantly lower in the sirolimus group compared to the paclitaxel group (4.4% vs 12.8%; p=0.043). Secondary angiographic endpoints, including late lumen loss and net lumen gain, and 1-year clinical outcomes were not significantly different between groups. In de novo non-left main CBL treatment, MV stenting accompanied by SB dilation with the sirolimus DCB was non-inferior to the paclitaxel DCB.