CT features in the early and late stages of chronic total coronary occlusions

Coronary chronic total occlusion on coronary CT angiography: what radiologists should know?

Coronary chronic total occlusion (CTO) often occurs in patients with obstructive coronary artery disease, which remains one of the greatest challenges for interventional cardiologists. Coronary computed tomography angiography (CCTA) with its emerging post-processing techniques can provide a detailed assessment of CTO lesions before percutaneous coronary intervention (PCI), playing an important role in the clinical management of CTO PCI, from early diagnosis, pre-procedural outcome prediction, the crossing algorithm planning, intraprocedural guidance, and finally post-procedural assessment and follow-up. In addition, the feasibility of CT perfusion (CTP) in patients with CTO has been validated. Combined CCTA and CTP have the great potential to be the one-stop-shop imaging modality for assessing both anatomy and function of CTO lesions. This review aims to make radiologists understand the role of CCTA in the diagnosis and assessment of CTO lesions, thus assisting interventionalists in optimizing CTO PCI crossing strategies with the expertise of radiologists.Critical relevance statement The anatomical features of CTO on CCTA can reveal the complexity of CTO lesions and are associated with CTO PCI outcome, thus helping interventionalists optimize CTO PCI crossing strategies.Key points • CTO is the common lesion in invasive coronary angiography, and CTO PCI is technically difficult and its success rate is relatively low.• Length, collaterals, and attenuation-related signs can help distinguish CTO from subtotal occlusion.• The anatomical features of CTO lesions can help grade the difficulty of CTO PCI and predict procedural outcomes and long-term outcomes of CTO PCI.• The real-time fusion of CCTA with fluoroscopic angiography can be applied in highly complicated CTO lesions.• After CTO PCI, CCTA can help guide a second CTO PCI re-entry or follow up stent patency.

Pericoronary adipose tissue attenuation predicts outcome of percutaneous intervention for chronic total occlusion

AIM

To investigate the association between pericoronary adipose tissue (PCAT) attenuation (PCATA) and outcomes of chronic total occlusion (CTO) after percutaneous coronary intervention (PCI), and to establish a clinical model that can be easily generalised to predict the outcomes of PCI-CTO.

MATERIALS AND METHODS

Between September 2015 and September 2019, patients from two centres were enrolled retrospectively. The primary endpoint was a procedural success (defined as achieving residual stenosis of <30% and a grade 3 thrombolysis in myocardial infarction [TIMI] flow). The new predictive model was generated by factors that were determined by multivariate analysis. The PCATA of CTO (PCATA-CTO) score was developed by assigning 1 point for each independent predictor, and then summing all points accrued. In addition, the predictive efficacy and interobserver and intraobserver agreement of PCATA-CTO and other scoring systems based on coronary computed tomography angiography (CCTA) were compared.

RESULTS

A total of 201 patients (mean age 58.9 ± 10.8 years, 85% male) were enrolled. The PCI success was achieved in 76% of the lesions. PCAT was higher in the PCI success group (-72.44 ± 10.45HU versus -76.76 ± 10.54 HU, p<0.05). Multivariable analysis yielded severe calcification, lesion length ≥15 mm, and perivascular fat attenuation index (FAI) ≤-69.5HU as independent negative predictors for procedural success. The area under the receiver operating characteristic curves for the PCATA-CTO score was 0.72. Comparing the PCATA-CTO score with other predictive scores, the PCATA-CTO score showed the highest interobserver (kappa = 0.74) and intraobserver agreement (kappa = 0.90, all p<0.01).

CONCLUSION

FAI ≤-69.5HU is an independent negative predictor of procedural success. The PCATA-CTO score improved the reliability of the prediction model. Its potential for clinical implementation requires evaluation.

Plaque modification in calcified chronic total occlusions: the PLACCTON study

INTRODUCTION AND OBJECTIVES

Severe calcification is present in> 50% of coronary chronic total occlusions (CTOs) undergoing percutaneous intervention. We aimed to describe the contemporary use and outcomes of plaque modification devices (PMDs) in this context.

METHODS

Patients were included in the prospective, consecutive Iberian CTO registry (32 centers in Spain and Portugal), from 2015 to 2020. Comparison was performed according to the use of PMDs.

RESULTS

Among 2235 patients, wire crossing was achieved in 1900 patients and PMDs were used in 134 patients (7%), requiring more than 1 PMD in 24 patients (1%). The selected PMDs were rotational atherectomy (35.1%), lithotripsy (5.2%), laser (11.2%), cutting/scoring balloons (27.6%), OPN balloons (2.9%), or a combination of PMDs (18%). PMDs were used in older patients, with greater cardiovascular burden, and higher Syntax and J-CTO scores. This greater complexity was associated with longer procedural time but similar total stent length (52 vs 57mm; P=.105). If the wire crossed, the procedural success rate was 87.2% but increased to 96.3% when PMDs were used (P=.001). Conversely, PMDs were not associated with a higher rate of procedural complications (3.7 vs 3.2%; P=.615). Despite the worse baseline profile, at 2 years of follow-up there were no differences in the survival rate (PMDs: 94.3% vs no-PMDs: 94.3%, respectively; P=.967).

CONCLUSIONS

Following successful wire crossing in CTOs, PMDs were used in 7% of the lesions with an increased success rate. Mid-term outcomes were comparable despite their worse baseline profile, suggesting that broader use of PMDs in this setting might have potential technical and prognostic benefits.

Inclusion of quantitative high-density plaque in coronary computed tomographic score system to predict the time of guidewire crossing chronic total occlusion

OBJECTIVE

This study aimed to establish a new scoring system that includes histological quantitative features derived from coronary computed tomographic angiography (CCTA) to predict the efficiency of chronic total occlusion percutaneous coronary intervention (CTO-PCI).

METHODS

This study analyzed clinical, morphological, and histological characteristics of 207 CTO lesions in 201 patients (mean age 60.0 [52.0-65.0] years, 85% male), which were recruited from two centers. The primary endpoint was a guidewire successfully crossing the lesions within 30 m. The new predictive model was generated by factors that were determined by multivariate analysis. The CCTA plaque (CTAP) score that included a quantitative plaque characteristic was developed by assigning an appropriate integer score to each independent predictor, then summing all points. In addition, the CTAP score was compared with other predictive scores based on CCTA.

RESULTS

The endpoint was achieved in 63% of the lesions. The independent predictors included previous CTO-PCI failure, the proximal blunt stump, proximal side branch, distal side branch, occluded segment bending > 45°, and high-density plaque volume (fibrous volume + calcified volume) ≥ 19.9 mm³. As the score increased from 0 to 5, the success rate of the guidewire crossing within 30 m decreased from 96 to 0%. Comparing the CTAP score with other predictive scores, the CTAP score showed the highest discriminant power (c-statistic = 0.81 versus 0.73-0.77, p value 0.02-0.07). The CTAP score showed similar results for procedural success.

CONCLUSION

The CTAP score efficiently predicted the guidewire crossing efficiency and procedural success.

KEY POINTS

• An increase in high-density plaque volume (fibrous + dense calcium) was more probable to reduce the efficiency of crossing and lead to procedural failure. • The new prediction scoring system with the addition of the quantitative characteristics of plaques had an improved predictive ability compared with the traditional prediction scoring system.

Natural History of Untreated Coronary Total Occlusions Revealed with Follow-Up Semi-Automated Quantitative Coronary CT Angiography: The Morphological Characteristics of Initial CT Predict Occlusion Shortening

Objective

To investigate the morphological changes of coronary chronic total occlusion (CTO) as determined by coronary computed tomography angiography (CCTA) follow-up using semi-automated quantitative analysis.

Materials and Methods

Thirty patients with 31 CTO lesions confirmed by invasive coronary angiography and baseline/follow-up CCTA were retrospectively included. CTOs were quantitatively analyzed by a semi-automated coronary plaque analysis software (Coronary Plaque Analysis, version 2.0, Siemens) after manually determining the lesion border. Recanalized lumen was defined as the linear-like enhanced opacity traversing the non-opacified occluded segment. Other parameters, such as total occlusion length, total occlusion volume, volume with low attenuation component (< 30 Hounsfield unit [HU]), volume with middle to high attenuation component (30–190 HU) as well as the calcification volume, were also recorded.

Results

Recanalized lumen was found within 48.4% (15/31) occlusions on the follow-up CCTA, compared to 45.2% (14/31) occlusions on the baseline CCTA. Eleven of 14 lesions (78.6%) with CT-visible recanalized lumen within CTOs had a shorter occlusion length on follow-up compared to only 3 of 17 lesions (17.6%) without CT-visible recanalized lumen (odds ratio, 17.1, p < 0.001). The percentage of low attenuation component of occlusions was smaller on follow-up CCTA compared to baseline value (18.1 ± 20.1% vs. 22.6 ± 19.6%, p = 0.033).

Conclusion

Coronary computed tomography angiography enables non-invasive characterization of natural progression of untreated CTO lesions. Recanalized lumen within CTOs observed at baseline CCTA was associated with shortening of occlusion length on follow-up. Compared to their earlier stage, occlusions of later stage were presented with higher density of non-calcified components.

Comparison of CT-RECTOR and J-CTO scores to predict chronic total occlusion difficulty for percutaneous coronary intervention

BACKGROUND

We sought to evaluate the ability of the CT-RECTOR and J-CTO scores to predict time-efficient guidewire (GW) crossing through a chronic total occlusion (CTO) and final procedure success.

METHODS

Data from 191 consecutive CTO lesions with pre-procedural coronary computed tomography angiography (CCTA) from our center were analyzed retrospectively. The difficulty of the procedure was classified as easy, intermediate, difficult, or very difficult according to CT-RECTOR and J-CTO scores. A successful GW crossing within 30min was set as the first endpoint. Final success of the procedure was set as the second endpoint. Receiver operating characteristic curves and net reclassification improvement (NRI) were used to compare the performance of both scores in predicting both endpoints.

RESULTS

The first and second endpoints were achieved in 55% and 76% of lesions, respectively. The NRI for prediction for both endpoints were 30.21% and 28.94%, respectively. Use of the CT-RECTOR score demonstrated a positive NRI for both the first (p=0.0027) and second (p=0.0190) endpoints. Compared with the J-CTO score (area under the curve: 0.76), the CT-RECTOR score (area under the curve: 0.85) yielded a higher predictive value for successful GW crossing within 30min (p=0.0018).

CONCLUSIONS

Compared with J-CTO, the CT-RECTOR scoring system provides a more accurate noninvasive tool for predicting time-efficient GW crossing and final procedure success. This scoring system, which is based on CCTA, may aid in the identification of very difficult CTO lesions and downstream management.