Super high-pressure balloon versus scoring balloon to prepare severely calcified coronary lesions: The ISAR-CALC randomised trial

Background: The comparative efficacy of balloon-based techniques to prepare severely calcified coronary lesions before stenting remains poorly studied. Aims: We sought to compare stent expansion following preparation of severely calcified coronary lesions with either a super high-pressure balloon or a scoring balloon. Methods: In this randomised, open-label trial, patients with severely calcified coronary lesions were enrolled at five centres in Germany and Switzerland. After unsuccessful lesion preparation with a standard non-compliant balloon (<30% reduction of baseline diameter stenosis), participants were randomised to predilation with either a super high-pressure balloon or a scoring balloon before drug-eluting stent (DES) implantation. The primary endpoint of the study was stent expansion index as assessed by optical coherence tomography (OCT). The key secondary endpoints included angiographic, strategy and procedural success. Results: OCT data after DES implantation were available for 70 out of 74 patients (94.6%) enrolled. Lesion preparation with a super high-pressure balloon versus a scoring balloon led to a comparable stent expansion index (0.72±0.12 vs 0.68±0.13; p=0.22). Compared with the scoring balloon, the super high-pressure balloon increased the minimum lumen diameter (2.83±0.34 mm vs 2.65±0.36 mm; p=0.03) and reduced the diameter stenosis (11.6±4.8% vs 14.4±5.6%; p=0.02) without difference in terms of angiographic success (100% vs 97.3%; p>0.99). Strategy success (91.9% vs 83.8%; p=0.48) and procedural success (100% vs 89.2%; p=0.12) were numerically more frequent with the super high-pressure balloon versus the scoring balloon. Conclusions: In patients with severely calcified coronary artery lesions, preparation with a super high-pressure balloon versus a scoring balloon was associated with comparable stent expansion on intravascular imaging and a trend towards improved angiographic performance.