Clinical outcomes of post-stent intravascular ultrasound examination for chronic total occlusion intervention with drug-eluting stents

Intravascular Ultrasound Guided Intervention in Calcified Coronary Lesions Showed Good Clinical Outcomes during One Year Follow-Up

BACKGROUND

Calcified coronary lesions can cause stent under-expansion, malapposition, and polymer degradation, hence increasing the risk of adverse clinical outcomes. Percutaneous coronary intervention (PCI) guided by intravascular ultrasound (IVUS) has been used regularly to improve outcomes. Our primary aim was to evaluate the clinical efficacy of IVUS-guided PCI in calcified coronary lesions.

METHODS

From August 2018 to December 2021, we prospectively included 300 patients in the CAPIRO study (CAlcified plaque in patients receiving Resolute Onyx^®) at three educational hospitals in Jeonbuk Province. We studied 243 patients (265 lesions) who were followed up for over a year. Based on coronary calcification by IVUS analysis, the patient population was categorized into two groups (Group I: non/mild calcification; Group II: moderate/severe calcification (maximum calcium arc >180° and calcium length > 5 mm)). One-to-one Propensity Score Matching was used to match the baseline characteristics. The stent expansion rate was analyzed by recent criteria. The primary clinical outcome was Major Adverse Cardiac Events (MACE), which included Cardiac death, Myocardial Infarction (MI), and Target Lesion Revascularization (TLR).

RESULTS

After follow-up time, the MACE rate in Group I was 1.99%, comparable to Group II's 1.09% (p = 0.594). The components of MACE did not significantly differ between the two groups. Based on absolute MSA or MSA/MVA at MSA site criteria, the stent expansion rate in Group II was lower than that of Group I. Nevertheless, based on recent relative criteria, the stent expansion rate in both groups was comparable.

CONCLUSIONS

After more than a year of follow-up, IVUS-guided PCI in moderate/severe calcification lesions was associated with good clinical outcomes, which was comparable with non/mild calcification lesions. Future studies with a larger sample size and a more extended follow-up period are required to clarify our findings.

A State-Of-The-Art Review on Coronary Artery Border Segmentation Algorithms for Intravascular Ultrasound (IVUS) Images

Intravascular Ultrasound images (IVUS) is a useful guide for medical practitioners to identify the vascular status of coronary arteries in human beings. IVUS is a unique intracoronary imaging modality that is used as an adjunct to angioplasty to view vessel structures using a catheter with high resolutions. Segmentation of IVUS images has always remained a challenging task due to various impediments, for example, similar tissue components, vessel structures, and artifacts imposed during the acquisition process. Many researchers have applied various techniques to develop standard methods of image interpretation, however, the ultimate goal is still elusive to most researchers. This challenge was presented at the MICCAI- Computing and Visualization for (Intra)Vascular Imaging (CVII) workshop in 2011. This paper presents a major review of recently reported work in the field, with a detailed analysis of various segmentation techniques applied in IVUS, and highlights the directions for future research. The findings recommend a reference database with a larger number of samples acquired at varied transducer frequencies with special consideration towards complex lesions, suitable validation metrics, and ground-truth definition as a standard against which to compare new and current algorithms.

Use of intravascular ultrasound for optimal vessel sizing in chronic total occlusion percutaneous coronary intervention

Aim

The aim of this study is to provide evidence on how use of standardized intravascular ultrasound (IVUS) use impacts stent size choice in the setting of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) compared to visual estimation.

Methods and results

Data of 82 consecutive patients who had successfully undergone IVUS-guided revascularization of CTO at the University Medical Center Mainz were analyzed. Angiography-based stent size prediction for the proximal and distal vessels was compared to the implanted stent diameter after IVUS assessment. Angiography-based stent size prediction for the proximal vessel was 3.09 ± 0.41, whereas IVUS use demonstrated larger vessel diameter, resulting in larger implanted stent diameter (3.24 ± 0.45, p < 0.001). Proximal vessel stent size prediction was underestimated in the majority of patients by angiographic estimation. Angiography-based stent size prediction for the distal vessel was 2.79 ± 0.38, whereas IVUS use demonstrated larger vessel diameter, resulting in larger implanted stent diameter (2.92 ± 0.39, p < 0.001).

Conclusion

Pre-stent IVUS assessment in CTO PCI provides important information on vessel morphology and size. Angiography-based stent size prediction for the proximal and distal vessels was frequently underestimated, IVUS use demonstrated larger vessel diameter, resulting in significantly larger implanted stent diameter.