Thread by @realdocdan

1/7 A thread 🧵Intravascular lithotripsy (IVL) can help modify calcified lesions - why doesn’t it harm soft tissue? Let’s dig deeper. A thread🧵@DGK_org @YoungDgk @AvrahamCooperMD @PCRonline @Dr_DanMD @SCAI @guilbon @Hannah_Billig_ @yourheartdoc1 #CardioTwitter #CardioEd

2/7 Back in 80s extracorporal shockwave lithotripsy was introduced as a novel noninvasive treatment of renal stones. 40 years into the future we’ve taken this technique to the next level #IVL #MedTwitter

doi.org/10.1016/S0301-…

3/7 Changes have been made to utilize shock waves intravascularly:
➡️emitters mounted on balloon angioplasty catheters delivering waves pulsatile & circumferential
➡️minimal peak negative pressure pulses (0.3 MPa)
➡️into target vessel via 0.014 wire
➡️balloon inflated to 4 atm

4/7 Shock waves are acoustic waves.
Upon reflection, positive turn into negative waves & vice versa. This leads to cavitation of water (formation of bubbles). As bubbles collapse, energy is released, generating secondary waves. This helps fragment plaques.
doi.org/10.1063/1.5092…

5/7 Now that we’ve seen that energy is released mainly when acoustic waves are reflected, it’s clear why they don’t harm soft tissue:
Reflection takes place at border zones of different impedances. Water & soft tissue have similar impedances; Imped. of calcified plaques is higher

6/7
Disrupt-CAD III and Disrupt-PAD III showed that lesion preparation with #IVL is safe and effective in a follow-up of 1 year.
➡️Disrupt-CAD III: doi.org/10.1016/j.jsca…
✍️ @djkereiakes, @GreggWStone et al. @SCAI
➡️Disrupt-PAD III: doi.org/10.1016/j.jsca…

7/7 In summary:
🥇Borderzones of impedance are places of generation of secondary waves & energy impact
🥈Emitters are in angioplasty balloons to keep IVL cool, to work w/ low peak neg. press & to align impedance btw balloon & soft tissue
🥉Lesion prep w/ #IVL is safe & effective

Here’s the link to the whole thread 🧵

https://twitter.com/realdocdan/status/1621904395221831680