Calcified nondilatable lesions remain a challenge and they are becoming more frequent as the overall complexity of interventions increases. Stent underexpansion is the main risk factor for restenosis and thrombosis, which is the most feared complication. Calcific coronary lesions impose a rigid obstacle to optimal balloon and stent expansion and the 20 to 30 atm limit that non-compliant (NC) balloons reach can be insufficient. The aim of our study was to evaluate the safety and efficacy of ultra high-pressure NC balloon (OPN NC; SIS Medical AG, Winterthur, Switzerland).

We retrospectively evaluated a consecutive series of 63 lesions in which conventional NC balloons at maximal pressure failed to achieve an adequate luminal gain and were therefore treated with an OPN NC balloon up to 40 atm.

61 patients with mean age 66.4 years of which 82% were male patients. 72% were hypertensive, 69% of them were diabetic, 17 patients had history of previous PCI, and 2 had undergone coronary artery bypass grafting. The clinical presentation was stable angina in 17 patients, unstable angina in 11, and myocardial infarction in 33 patients. Among the angiographic characteristics the culprit vessel was the left main coronary artery in 1 patient, left anterior descending coronary artery (LAD) in 43, left circumflex coronary artery (LCX) in 8, right coronary artery (RCA) in 10 and SVG in 1. All patients had atleast moderate degree of calcification on the angiogram. The OPN NC balloon was used for plaque preparation before stent implantation in 37 patients, for stent post dilatation due to underexpansion in 15 patients, for treatment of ISR in 7 patients and for both plaque preparation and stent postdilatation due to underexpansion in 2 patients. Predilatation using a semi-compliant balloon was performed in most of the cases and was then followed by a successive dilatation using a conventional NC balloon, sized according to conventional angiographic criteria and inflated up to the rated burst pressure or slightly higher. In all cases, the dilatation performed with the conventional NC balloon failed to achieve an adequate balloon expansion and luminal gain. After the failed attempt the OPN NC balloon with the same diameter as the conventional NC balloon was inflated up to 40 atm. Angiographic and technical success with OPN NC balloons was achieved in 62 lesions (98.4%). 1 patient had coronary perforation requiring covered stent. In 2 cases there is shaft rupture of OPN NC balloon at 40atm and balloon rupture at 35atm in 2 cases. No in-hospital or 30-day MACE was reported.

When conventional NC balloons fail, OPN NC dedicated ultra high-pressure balloon provides an effective and safe alternative strategy for the dilatation of resistant coronary lesions.