Intravascular ultrasound assessment of the effects of rotational atherectomy in calcified coronary artery lesions

Abstract

We sought to clarify intravascular ultrasound (IVUS) features of rotational atherectomy (RA) of calcified lesions. IVUS was performed post-RA and post-stent in 38 lesions and analyzed every 1 mm. Pre-intervention IVUS was performed when the IVUS catheter crossed the lesion (n = 11). Calcium Index was average calcium angle multiplied by calcium length. We compared lowest (n = 13), middle (n = 13), and highest (n = 12) Calcium Index tertiles. Reverberations (multiple reflections from calcium) with a concave-shaped lumen in the post-RA IVUS were considered to represent RA-related calcium modification. Newly visible perivascular tissue through a previously solid arc of calcium in the post-stent IVUS was also evaluated. Comparing the pre and post-RA IVUS, maximum reverberation angle, and length increased significantly after RA (angle, from 45° [31, 67] to 96° [50, 148], p = 0.003; length, from 4.0 mm [2.0, 6.0] to 8.0 mm [4.0, 14.0], p = 0.005). In the post-RA IVUS, reverberations had a larger angle in the middle and highest Calcium Index tertiles (lowest, 91° [64, 133]; middle, 135° [107, 201]; highest, 150° [93, 208], p = 0.03). Post-stent newly visible perivascular tissue was more frequent in the middle and highest Calcium Index tertiles (lowest, 30.8%; middle, 69.2%; highest, 75.0%, p = 0.049). Minimum stent area was similar after calcium modification by RA irrespective of the severity of the Calcium Index (lowest, 6.7 mm [5.7, 8.9]; middle, 5.6 mm [4.9, 6.8]; highest, 6.7 mm [5.9, 8.2], p = 0.2). Greater calcium modification by RA occurs in severely calcified lesions with smaller lumen diameters to mitigate against stent underexpansion.

Comparison of the incidence of slow flow after rotational atherectomy with IVUS-crossable versus IVUS-uncrossable calcified lesions

“…Second, our results may be useful for establishing an educational program for junior RA operators. Because many literatures regarding RA and imaging devices have been published 1,[3][4][5][6][7][8][9][10] , even junior RA operators may be able to select an appropriate burr size, RotaWire, and RA strategy as long as an imaging device can cross the lesion before RA. However, as we shown here, there were many lesions that an IVUS catheter cannot cross, and the incidence of slow flow was greater in IVUS-uncrossable lesions.…”

“…Recently, many groups rigorously published research articles regarding RA with intravascular imaging devices 3 , 4 , 6 – 9 . Moreover, several review articles explain the interpretation of intravascular imaging findings in RA to facilitate use of imaging devices in RA 1 , 5 , 10 .…”

“…However, the incidence of severe complications is greater in percutaneous coronary interventions (PCI) with than without RA 2 , demanding further refinement in RA. Intravascular imaging devices including intravascular ultrasound (IVUS) and optical coherence tomography (OCT) can provide useful information regarding calcification such as depth, longitudinal length, and arch of calcification 3 – 6 . Therefore, intravascular imaging devices have been frequently used in current PCI with RA 7 – 9 .…”

Cardiovascular imaging 2018 in the International Journal of Cardiovascular Imaging

“…By utilizing this device with the rotational speed raging between 160,000 and 200,000 rpm they showed that minimum lumen area, maximum reverberation number, angle, and length increased post atherectomy, which indicates calcium modification. In addition newly visible perivascular tissue through previously solid calcium (indicating calcium fracture) was observed [25].…”

Recognition of Angiographic Atherosclerotic Plaque Development Based on Deep Learning

“…The VH-IVUS technique utilizes backscattered ultrasound RF signals to perform feature extraction to identify plaque development by power spectral processing, including Fourier transform, welch power spectrum, and autoregressive models. Although this method can classify the degree of plaque development and reconstruct tissue histological images similar to histopathological sections [5], [6], it still has limitations. For example, the recognition ability of borders in VH-IVUS images is poor, usually requires manual Calibrated and the image reconstruction time is longer.…”