Calcium Fracture Detection by Optical Coherence Tomography Versus Intravascular Ultrasound Following Intravascular Lithotripsy.

Both OCT and IVUS significantly underestimated the occurrence of IVL-induced calcium fractures compared with the micro-CT gold standard.

• Ex vivo study of 5 cadaveric hearts with 15 heavily calcified coronary lesions.
• OCT, IVUS, and micro-CT were obtained before and after IVL treatment.
• Fracture detection rates were compared across modalities.

OCT had higher fracture detection sensitivity than IVUS after IVL.

• The difference was significant (P < 0.05 by McNemar's test).
• The same lesions were imaged with both modalities and compared against micro-CT.
• This follows the authors' prior finding that OCT misses approximately half of fractures.

Narrow linear nondisplaced fractures seen on OCT were frequently undetectable on IVUS or appeared only as subtle hyperechoic shadows.

• Appearance patterns of fractures were compared across modalities.
• Fractures that were visible on OCT often had no clear IVUS correlate.

IVUS detectability of fractures is strongly dependent on fracture width, with an OCT-measured width above 115 μm identified by IVUS with excellent diagnostic performance.

• ROC analysis evaluated OCT-measured fracture width thresholds for IVUS detectability.
• Area under the curve was 0.99 (95% CI: 0.98-1.00).
• At the >115 μm threshold, sensitivity was 100% and specificity was 92%.

Absence of a visible fracture on OCT or IVUS does not exclude calcium modification by IVL.

• Micro-CT revealed fractures that both imaging modalities missed.
• The authors conclude that lack of visible fracture should not be interpreted as lack of lesion modification.