Yet more accessible chronic total occlusion (CTO) lesions PCI remain technically challenging and associated with uncertain prognosis improvement and a higher risk of stent failure. However, most of these interventions are solely guided by angiography which can be often be misleading for the operator and leads to suboptimal results. In this perspective, the use of intracoronary imaging represents a valuable addition to improve outcomes.

The aim of the present work was to compare the results of angiography and intra Vascular ultrasound (IVUS) in evaluation of successfully deoccluded CTO lesions.

This series included patients with successfully deoccluded complex CTO lesions (median J CTO score 2 [1-2]) in our center from 2017 to 2022 that were treated with an antegrade wire escalation approach. After the lesion was crossed with wire and microcatheter, predilation was performed with a 2.0 compliant balloon and the lesion was analyzed by IVUS. The pre and post deocclusion angiography views as well as the pre/post stenting IVUS runs were centrally reviewed by an operator unaware of the procedure results. A dedicated software (CAAS 7.0, Pie Medical) was used for quantitative coronary angiography analysis (QCA). The following parameters were assessed: position of the wire (extraplaque /intraplaque), calcium burden & presence of calcified rings, vessel dimensions and lesion length. The series included a total of n=43 CTO lesions were located on LAD (39,5%), Cx (20,9%), and RCA (34,9%). The median J-CTO score was 2[1-2]. We observed significant discrepancies in wire position assessment between techniques: the wire was more frequently identified in extraplaque position with IVUS compared to angio (35.7% vs. 16.3%, p=0.001). The presence of extraplaque wire was associated with more complex procedures including higher volume of contrast (400 ml [350-510] vs 222 ml [195-273]; p<0.001) and X ray exposure time (42.1 min [31-53] vs 29.4 [20.4-34,3], p=0.001). Similar results were observed for calcium burden analysis: severe calcifications were identified in 66.7% by IVUS vs.34.9% by angio (p=0.002). In addition, presence of one or more annular calcification was observed in 44% of the lesions by intra coronary imaging. We observed discrepancies in vessel dimensions according to the measurement methods. Hence, length, distal and proximal diameters values were significantly larger when measured with IVUS compared to QCA (respectively: 41.5 mm [33.5-54.6] vs 55.4 mm [42.57-71.82], p=0.001; 1.87 mm [1.6-2.] vs 2.52 mm [2.2-2.78], p<0.001; 2.52 mm [2.15-3] vs 3.54 mm [3.22-4], p<0.001). Finally, peri-medial hyperechoic bands (PHB/ an IVUS sign associated with long term regain of native vessel caliber following recanalization) was observed in 44 % of the cases.

Our results suggest that angiography alone frequently underestimates the lesion severity and dimensions of the vessels in CTO, which might affect the results of the stent implantation and IVUS analysis could represent a valuable tool to improve the overall PCI accuracy and precision in this situation.

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