LAUSR

Heavily calcified coronary lesion is one of the worst enemies for interventional cardiologists. These difficult to dilate lesions consume time and equipment, require proficiency with adjunctive calcification modifying tools like rotational atherectomy (RA), and are associated with higher rates of dreaded procedural complications namely perforation, dissection and stent under expansion leading to unfavorable shortand long-term outcomes. In recent years, a variety of devices for modifying calcified lesions have become available. The easy to use cutting and scoring balloons perform best for mild to moderately calcific lesions. Severely calcified lesions can only be treated effectively using rotational/orbital atherectomy or ultra-high pressure (up to 40 atm) noncompliant (NC) OPN balloons. The atheroablative techniques not only require acquired skill-set and a learning curve but also carry an increased risk of vessel perforation, slow flow, dissection, and vessel closure. The latest addition to our armamentarium of devices to treat severely calcified lesion is Intravascular Shockwave Lithotripsy (IVL). This device uses sonic waves to fracture calcium within the vessel wall. It also provides a number of inherent advantages, being a balloon catheter based device. It is intuitively user friendly, has a short learning curve and is safe with very little risk perforation, distal embolization or slow flow. It has the ability to create circumferential fractures in superficial and deep calcium at low pressure thus making the lesion more uniformly compliant to achieve optimal stent expansion. The prospective, single arm, multicentre, non-randomized DISRUPT CAD studies (I, II, III, IV) enrolled a total of 628 patients with denovo severely calcified lesions and demonstrated excellent safety (no IVL associated perforation, vessel closure or no reflow) and high effectiveness. However, these studies were performed principally for regulatory approvals and excluded many 'real-life' lesions like tortuous vessels, undilatable lesions, ostial lesions, total occlusions, unprotected left main lesions, in stent restenosis and true bifurcation lesions. Thus, 'real-world' data for IVL is sparse and very much needed. In this issue of the journal, Aziz et al add to our knowledge base by presenting a pooled experience of 190 'real-world' patients with calcified lesions undergoing IVL at six experienced European centers. It is important to note that in 74% patients, the use of IVL was as a bailout strategy after failure to adequately dilate the lesion with a non-compliant balloon. 23% patients had instent restenosis, 15% had left main stenosis, 7% had chronic total occlusion, 8% had Acute ST elevation MI, 17% underwent RA to facilitate use of IVL and 15% underwent multi vessel PCI. These 'real-life' lesions were excluded from the DISRUPT CAD studies. Intravascular imaging prior to PCI/IVL was performed in 19 (10%) patients and post stent for result optimization in 40 (21%) patients only. The device success rate was 99.5% (only one case of failure to deliver the IVL balloon across the lesion). The procedural success rate was 99%, the complication rate was relatively high related to perforations in 6 (3%) cases of whom one died in hospital. These perforations were not related to IVL but occurred following stent implantation and non-compliant balloon post dilatation. At short term (median 7 month) follow up, the event rates in this highly complex group of calcified lesions were very good, cardiac death 1%, Target vessel MI 0.5%, stent thrombosis 0.5%, Target lesion revascularization 1.5% and Major Adverse Cardiac events 2.6%. The authors also suggest a 'real-world algorithm' for treating calcified lesions where they exclude intravascular imaging by justifying that it is less commonly used in 'real-world' practice due to cost and time constraints! There is no doubt that IVL is establishing itself as a safe and effective treatment for a variety of severely calcified lesions in challenging anatomies including the biggest nemesis, the circumferential calcium Received: 14 June 2021 Accepted: 18 June 2021