Preliminary study of the significance of reverberation by IVUS detection for patients with severe calcified lesions.

To explore the potential significance of the reverberation of calcification by comparing both intravascular ultrasound (IVUS) and optical coherence tomography (OCT) measurement post manual coregistration. The reverberation phenomenon is often detected by IVUS for severe calcified lesions post rotational atherectomy (RA), which is thought to be due to the glassy and smooth inner surfaces of calcifications. Because of the poor penetration of IVUS, it is impossible to measure the thickness of calcifications, and the relationship between multiple reverberations and the thickness of calcification lesions has not been reported before. A total of forty-nine patients with severe calcified coronary lesions that were detected by IVUS and OCT simultaneously were enrolled in our retrospective study. If reverberation phenomena were detected by IVUS, intravascular imaging (IVI) data (including distance between the IVUS catheter center and the inner surface of the reverberation signal, the intervals between all adjacent reverberation signals, the number of layers of reverberation in IVUS, and the thickness of the calcification in OCT) were measured at the same position and same direction (each cross-section had 4 mutually perpendicular directions) at 1-mm intervals. The correlation between each reverberation observational value and OCT data was the primary target in this retrospective study, and the correlation between reverberation and calcium crack post predilatation was analyzed in other 15 patients. Four hundred twenty-eight valid observational points were analyzed simultaneously by IVUS and OCT; among them, 300 points had a single layer of reverberation, 83 had double layers of reverberation and 42 had multiple layers (≥ 3 layers) of reverberation by IVUS detection post-RA. Multivariate logistic regression analysis showed that the number of layers of reverberation by IVUS was significantly related to the thickness of calcifications by OCT at the same point and in the same direction (p < 0.001). Single, double, and multiple layers of reverberation in IVUS correspond to median calcification thicknesses (interquartile ranges (IQRs)) of 0.620 mm (0.520-0.720), 0.950 mm (0.840-1.040) and 1.185 mm (1.068-1.373), respectively, by OCT detection. Another 100 points in other 15 patients with integrated IVUS data pre- and post-predilatation showed that only single layer of reverberation was related to calcium crack (p < 0.001). The number of layers of reverberation signal detected by IVUS is positively correlated with the thickness of calcifications measured by OCT post-RA and single layer of reverberation is correlated to calcium crack post-predilatation.

Predictors of vessel quantitative flow ratio loss in patients with severely calcified lesions after rotational atherectomy.

BACKGROUND: Previous studies have established that moderately to severely calcified lesions (MSCL) are associated with high rates of major adverse cardiovascular events, even when drug-eluting stents are implanted after rotational atherectomy (RA). Yet, the changes in coronary function indexes during follow-ups have never been investigated. The quantitative flow ratio (QFR), a novel coronary function index, has been increasingly adopted in daily practice in recent years. METHODS: A total of 111 MSCL patients were retrospectively enrolled in this study. The vessel QFR (QFRv) loss was defined as post-percutaneous coronary intervention QFRv minus follow-up QFRv. The study subjects were divided into high QFRv loss (n = 51) and low QFRv loss (n = 60) groups according to the binary method. The obtained predictors of QFRv loss were then analyzed. RESULTS: The results showed that the final burr-to-vessel ratio (B to V ratio) in the high QFRv loss group decreased significantly compared to the low QFRv loss group (p < 0.01). The univariate and multivariate regression analyses indicated that the final B to V ratio was an excellent predictor of QFRv loss. The cut-off value of the final B to V ratio for QFRv loss prediction was 0.50 (sensitivity: 50.98%, specificity: 68.33%, and area under the curve: 0.627 [95% confidence interval: 0.530-0.717], p < 0.05). Additionally, the target vessel failure incidence in the high QFRv loss group was higher than in the low QFRv loss group (p < 0.01). CONCLUSIONS: An increased burr-to-vessel ratio can prevent QFRv loss in patients with MSCLs after RA, an effect that might be closely associated with a low target vessel failure incidence.