Intravascular lithotripsy for treatment of stent underexpansion secondary to severe coronary calcification

A 73-year old man was found to have proximal left anterior descending (LAD) in-stent stenosis (ISS) secondary to stent underexpansion as a cause of limiting angina. Despite serial dilations, including 3.5 mm OPN NC® High-Pressure PTCA (SIS Medical AG; Switzerland) to >40 atm, percutaneous coronary intervention (PCI) was unsuccessful on multiple occasions (Panel A). In September 2018, the patient re-presented with recurrent angina, and angiography identified a high-grade proximal LAD lesion (Panel B, Supplementary material online, Video S1). Optical coherence tomography (OCT) confirmed severe ISS with minimal stent area (MSA) 1.09 mm2 secondary to stent underexpansion due to concentric severe coronary calcification (Panel C–F, Supplementary material online, Video S2). A C2 4.0 × 12 mm Shockwave (Fremont, CA, USA) intravascular lithotripsy (IVL) balloon was advanced across the lesion and inflated to 4 atm. During the second round of 10 pulses, the balloon fully expanded (Panel G, Supplementary material online, Video S3). Angiography confirmed successful PCI with minimal residual diameter stenosis (Panel H, Supplementary material online, Video S4). Repeat OCT showed multiple calcium fractures at the site of ISS, with post-IVL stent area of 6.47 mm2 (Panel I–L, Supplementary material online, Video S5). The procedure was completed using a 4.0 × 15 mm drug-eluting balloon (SeQuent, B Braun) without additional DES placement and a final stent area of 6.55 mm2 at the site of previous MSA. IVL is a new technology, in which multiple lithotripsy emitters mounted on a traditional catheter platform deliver localized pulsatile sonic pressure waves liberating extreme bursts of energy. We illustrate treatment of high-grade ISS secondary to severe coronary calcification with IVL for the first time, where historically there have been limited treatment options. (Panel A) Ultra-high-pressure inflation of non-compliant OPN balloon failed to expand the lesion within the stent (arrowheads). (Panel B) Angiography shows a severe proximal left anterior descending stenosis (arrowheads) at the site of previous stent implantation. (Panels C–F) OCT identifies severe stent underexpansion secondary to concentric calcification with minimal and maximum calcium thickness of 0.86 mm and 1.35 mm, respectively, and minimal lumen area of 1.09 mm2. (Panel F) Stent rendering shows the severity of stent underexpansion (white arrowheads). Following IVL, 60 shocks delivered during six rounds of therapy, with a 4.0 × 12 mm device. (Panel G) Balloon expansion is considerably improved and (Panel G) there is angiographic success with minimal residual diameter stenosis. (Panels I–K) Minimal lumen area increased from 1.09 mm2 to 6.47 mm2 following IVL with OCT showing multiple calcium fractures (arrowheads). (Panel L) Stent rendering shows significant improvement in stent expansion (white arrowheads).