Background: Severe coronary calcifications are commonly encountered in real-world populations and in left main (LM) disease, heightening complication risks including stent underexpansion. Although intravascular lithotripsy (IVL) appears safe, longer-term data in high-risk populations are lacking. The aim of this study was therefore to examine 1-year IVL outcomes for severely calcified lesions in two complex cohorts: LM stenosis and underexpanded stents (UES) during stent implantation. Methods: A registry study was carried out to examine major adverse cardiovascular events (MACEs) (MI, target vessel revascularisation [TVR], cardiac mortality). The LM and UES subgroups were compared with their counterparts in the non-LM and de novo lesion subgroups, respectively. Results: The study involved 102 participants (median age, 70 years, 68% male), and the cardiovascular burden was high (diabetes, 72%; dialysis, 18%; prior MI, 43%, median left ventricular ejection fraction, 45%). Many participants presented acutely (acute coronary syndrome, 36%; decompensated heart failure, 13%) and had complex anatomies (triple-vessel disease, 77%). The cardiovascular burden was higher in the LM and UES subgroups than in the non-LM and de novo lesion subgroups, but the rates of procedural complications and 30-day MACEs were low and were not significantly different. The 1-year MACE rate was higher in the LM group than in non-LM (29% versus 10%, p=0.042), but was non-significant after adjusting for baseline variables (OR 3.08; 95% CI [0.87–10.9]); the rates of 1-year MI, TVR and mortality did not differ from non-LM. In the UES group, 1-year MACE rate (17% versus 13%, p=0.500) was similar to that for de novo lesions. Conclusion: The preliminary data suggest that the use of IVL is reasonable when encountering stent underexpansion due to severe coronary calcifications during stent implantation. The 1-year MACE rate was higher in calcific LM stenosis, probably due to greater comorbidity burden and acute presentations.
