Intravascular ultrasound can be used to evaluate pulsed laser ablation of arterial tissue.

BACKGROUND AND OBJECTIVE

Intravascular ultrasound (IVUS) has been used successfully to detect intravascular lesions. This study evaluates the ability of IVUS to detect acoustic damage to the arterial wall following high power, pulsed laser ablation.

STUDY DESIGN/MATERIALS AND METHODS: Arterial ablation and disruption were performed in necropsy bovine aorta with a Ho:YAG laser using energy ranging from 140-720 mJ/pulse at 5 Hz. Laser energy was delivered with 2 mm diameter, multifiber over-the-wire catheters. A 20-MHz IVUS catheter was used to image the arterial damage prior to tissue fixation and morphometry.

RESULTS

IVUS images revealed ablation craters surrounded by high acoustically backscattering zones. By histology, the arteries revealed ablation craters lined with thermal coagulation surrounded by a region of dissection and vacuolization. The depth and width of the highly backscattering zones on IVUS images correlated strongly with the corresponding morphometric measurements of tissue dissection (r = 0.92, P = 0.0001 and r = 0.80, P = 0.0001, respectively). Morphometric measurements of the ablation crater depth correlated strongly with laser energy (r = 0.90, P = 0.0001), whereas crater width was not correlated with laser energy (r = 0.27, P = 0.09).

CONCLUSION

This study demonstrates that IVUS can detect and measure the extent of arterial damage following pulsed laser ablation. This may provide a means of detecting the extent of tissue disruption and help develop approaches to reduce or prevent extensive tissue damage.