The following are key points to remember from this state-of-the-art review on principles of intravascular lithotripsy (IVL) for calcific plaque modification:

1. Vascular calcification is a common finding both in the peripheral and coronary vascular beds and its presence negatively impacts clinical outcomes after percutaneous interventions.
2. Available techniques for modifying coronary calcium include use of cutting or scoring balloon and atheroablation.
3. IVL is based on the established therapeutics strategy of using acoustic pressure waves (electrohydraulic lithotripsy) to treat renal calculi, with specific modifications. Lithotripsy emitters have been incorporated on the shaft of a balloon angioplasty catheter that deliver localized pulsatile acoustic pressure wave circumferentially to modify vascular calcium. Leading edge of the shockwave imparts compressive stress once calcium is encountered and induces fracture.
4. Shockwave IVL catheter is a single use, sterile, disposable catheter that contains multiple spark gap-based lithotripsy emitters along the shaft of an integrated balloon. The catheter is programmed to deliver a pre-defined number of pulses at 1 pulse/second. The balloon is inflated to subnominal pressures (4 atm), which facilitates enough interface to transmit shockwave energy to vascular tissue.
5. IVL pressure waves deliver tissue-safe positive and minimal peak negative pressure pulses to allow compressive force to modify vascular calcium. Pressure wave emitters are enclosed within an inflated, fluid-filled balloon to mitigate thermal injury, and multiple emitters are arranged in series along the shaft of the catheter to longitudinal treatment in a vessel.
6. Shockwave M5 and S4 IVL catheters are approved for use in peripheral vascular beds and pooled analysis shows consistent reductions in residual luminal diameter stenosis after IVL in moderate to severely calcified lesions. In addition, there is increasing clinical use of IVL to facilitate placement of large bore catheters for transfemoral procedures like transcatheter aortic valve replacement.
7. Shockwave C2, the coronary platform, was approved in Europe in 2018 after completion of the DISRUPT CAD I trial.
8. In total, over 600 patients have been studied across the globe. Findings support the concept that IVL modifies both superficial and deep calcium by producing multiplane, circumferential, and longitudinal calcium fractures with consequent enhancement of transmural vessel compliance leading to stent expansion. Procedural success rates are reported to be >90% and 30-day major adverse cardiac event rates have been low.
9. Improvements in device deliverability, available sizes (currently maximum size 4.0 mm for coronaries and 7.0 mm for peripheral), and increase in the total number of pulses delivered per catheter are expected to improve the technology further.
10. Long-term data on clinical outcomes are needed. Several ongoing trials are studying application of IVL in other lesion subsets such as in-stent restenosis and underexpanded stents, and with other calcium-modifying therapies.

Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Stable Ischemic Heart Disease, Atherosclerotic Disease (CAD/PAD), SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Aortic Surgery, Cardiac Surgery and Arrhythmias, Cardiac Surgery and SIHD, Interventions and Coronary Artery Disease, Interventions and Vascular Medicine, Chronic Angina

Keywords: Ablation Techniques, Angioplasty, Balloon, Catheters, Constriction, Pathologic, Coronary Artery Disease, Coronary Restenosis, Kidney Calculi, Lithotripsy, Lithotripsy, Laser, Percutaneous Coronary Intervention, Peripheral Arterial Disease, Plaque, Atherosclerotic, Stents, Transcatheter Aortic Valve Replacement, Vascular Calcification

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