Analysis of Plaque Composition in Coronary Chronic Total Occlusion Lesion Using Virtual Histology-Intravascular Ultrasound

Predictive performance of the perivascular fat attenuation index for interventional antegrade percutaneous coronary intervention for chronic total occlusion

OBJECTIVES

This study aimed to investigate the association between the perivascular fat attenuation index (FAI) and the success of the antegrade percutaneous coronary intervention (PCI) for chronic total occlusion (CTO).

METHODS

This study evaluated patients with only one CTO lesion observed on conventional coronary angiography (CAG) who underwent coronary computed tomography angiography (CCTA) < 1 month before CAG, from 2018 to 2019. The clinical data, CCTA-based CTO lesion morphologic characteristics, and perivascular FAI of CTO lesions were recorded and analysed.

RESULTS

In total, 156 patients with CTOs were enrolled in this study. Successful antegrade PCI (A-PCI) was achieved in 105 CTO lesions (67.3%). The perivascular FAI of the failed A-PCI group was significantly lower than the successful A-PCI group (-84.76 ± 10.44 Hounsfield unit (HU) vs. -67.54 ± 9.94 HU; p < 0.001), and the cut-off value determined by the receiver operating characteristic (ROC) curve was -77.50 HU. Multivariable analysis revealed no statistical significance in the clinical data, FAI ≤ -77.50 HU (odds ratio (OR): 33.96), negative remodeling (OR: 4.36), severe calcification degree (OR: 4.43) and occlusion length ≥ 20.25 mm (OR: 3.89) were independent predictors of A-PCI failure. The prediction performance of combining the three morphologic characteristics (severe calcification, occlusion length ≥ 20.25 mm, and negative remodeling) with FAI ≤ -77.50 HU was better than that of the three morphologic characteristics alone (0.93 versus 0.77, p < 0.001).

CONCLUSIONS

As a non-invasive index for detecting coronary inflammation, FAI complements indicators based on coronary CTA well and may be helpful for choosing appropriate interventional strategies.

KEY POINTS

• Perivascular FAI of CTO was significantly higher in the failed A-PCI group. • The combination of FAI with other morphological predictors showed higher predictive performance of failed A-PCI for CTOs. • FAI is a good complement to indicators based on coronary CTA.

A Novel Classification for Predicting Chronic Total Occlusion Percutaneous Coronary Intervention

Aims

Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is characterized by a low success rate and an increase in complications. This study aimed to explore a new and simple classification method based on plaque composition to predict guidewire (GW) crossing within 30 min of CTO lesions.

Methods

This study consecutively enrolled individuals undergoing attempted PCI of CTO who underwent coronary computed tomographic angiography (CCTA) within 2 months. Lesions were divided into soft and hard CTO groups according to the necrotic core proportion.

Results

In this study, 207 lesions were divided into soft (20.3%) and hard CTO (79.7%) groups according to a necrotic core percentage cutoff value of 72.7%. The rate of successful GW crossing within 30 min (57.6 vs. 85.7%, p = 0.004) and final success (73.3 vs. 95.2%, p = 0.001) were much lower in the hard CTO group. For patients with hard CTO, previous failed attempt, proximal side branch, bending > 45 degrees calcium ≥ 50% cross-sectional area (CSA), and distal reference diameter ≤ 2.5 mm were demonstrated to be associated with GW failure within 30 min. For patients with soft CTO, only blunt entry was proved to be an independent predictive factor of GW failure within 30 min.

Conclusions

Grouping CTO lesions according to the proportion of necrotic core is reasonable and necessary in predicting GW crossing within 30 min. A soft CTO with a necrotic core is more likely to be recanalized compared with a hard CTO with fibrous and/or dense calcium. Different plaque types have variable predictive factors.

Current approaches for treatment of coronary chronic occlusions

Introduction: Coronary chronic total occlusions (CTO) represent a challenging subset in interventional cardiology.Areas covered: During the last decade, improvements in materials, techniques, and meticulous pre-procedural lesion assessment have increased the success rate in CTO lesions. Several scores have been developed to address overall lesion evaluation and help select the most appropriate treatment strategy. In addition, specific algorithms such as the hybrid algorithm have been introduced to provide a framework for CTO operators and a rapid management of the various challenging aspects of the procedure. The hybrid approach requires operator's ability to switch from one treatment strategy to another when the first one appears to be unsuccessful. Adequate training and operators' experience remain crucial to improve the likelihood of success.Expert opinion: The aim of this review is to provide insights and guidance for operators on current approaches for treatment of CTO and complication management.

Evolution of nonculprit coronary atherosclerotic plaques assessed by serial virtual histology intravascular ultrasound in patients with ST-segment elevation myocardial infarction and chronic total occlusion

OBJECTIVE

The pathophysiology and natural course of coronary nonculprit plaques remain unclear. We investigated whether the short-term natural course of nonculprit plaques differs between ST-segment elevation myocardial infarction (STEMI) and chronic total occlusion (CTO) patients.

METHODS

We performed serial virtual histology intravascular ultrasound on nonculprit plaques in 26 STEMI and 11 CTO lesions at baseline and the 6-month follow-up.

RESULTS

At baseline, more lesions in the STEMI group were virtual histology intravascular ultrasound-derived thin-cap fibroatheromas (TCFA; 76.9 vs. 18.1%, P=0.002). During the follow-up period, the plaque composition changed dynamically in the STEMI group (fibrofatty: 9.8±1.9 to 17.3±2.9%, P=0.030; dense calcium: 12.7±1.8 to 8.1±1.7%, P=0.026; necrotic core: 21.1±1.8 to 15.4±2.2%, P=0.052), with a consistent plaque size. In the CTO group, the plaque composition and plaque size remained consistent without a significant change. Also, more lesions in the STEMI group remained as or progressed to TCFA, compared with the CTO group (67 vs. 11%, P=0.089). Factors associated with a persistent TCFA or with a new development of TCFA were a large necrotic core volume index and the diagnosis of STEMI, whereas new statin usage was a protective factor.

CONCLUSION

Nonculprit lesions in STEMI patients were more unstable at the baseline compared with those in CTO patients. During follow-up, nonculprit lesions in STEMI and CTO patients showed a distinct pattern of change; the former were stabilized in plaque composition, whereas the latter remained consistent. The diagnosis of STEMI and a large necrotic core volume were predictors of evolution to a TCFA, and new statin usage was a protective factor.