Why and How Should We Treat Chronic Total Occlusion? Evolution of State-of-the-Art Methods and Future Directions

Association between hibernating myocardium and collateral circulation in patients with coronary chronic total occlusion

Objective

To explore the association between the quantity of hibernating myocardium (HM) and collateral circulation in patients with coronary chronic total occlusion (CTO).

Materials and methods

88 CTO patients were retrospectively analyzed who underwent evaluation for HM using both 99mTc-sestamibi Single photon emission computed tomography (99mTc-MIBI SPECT) myocardial perfusion imaging (MPI) combined with 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) myocardial metabolism imaging (MMI). They were divided into two groups according Rentrop grading: the poorly/well-developed collateral circulation group (PD/WD group, Rentrop grades 0-1/2-3). After adjusting for the potential confounding factors and conducting a stratified analysis, we explored the association between the HM index within CTO region and the grading of collateral circulation.

Results

In the WD group, the HM index was notably higher than PD group (46.2 ± 15.7% vs. 20.9 ± 16.7%, P < 0.001). When dividing the HM index into tertiles and after adjusting for potential confounders, we observed that the proportion of patients with WD rose as the HM index increased (OR: 1.322, 95% CI: 0.893-1.750, P < 0.001), the proportion of patients with WD was 17.4%, 63.3%, and 88.6% for Tertile 1 to Tertile 3.This increasing trend was statistically significant (OR: 1.369, 95% CI: 0.873-1.864, P < 0.001), especially between Tertile 3 vs. Tertile 1 (OR: 4.330, 95% CI: 1.459-12.850, P = 0.008). Curve fitting displaying an almost linear positive correlation between the two.

Conclusion

The HM index within CTO region is an independent correlation factor for the grading of coronary collateral circulation. A greater HM index corresponded to an increased likelihood of WD.

Assessment of Myocardial Viability and Risk Stratification in Coronary Chronic Total Occlusion: A Qualitative and Quantitative Stress Cardiac MRI Study

BACKGROUND

Indicators for assessing myocardial viability and risk stratification in patients with coronary chronic total occlusion (CTO) are still in the research stage.

PURPOSE

To use stress-MRI to assess myocardial function, blood perfusion, and viability and to explore their relationship with collateral circulation.

STUDY TYPE

Prospective.

SUBJECTS

Fifty-one patients with CTO in at least one major artery confirmed by X-ray coronary angiography (male: 46; age 55.2 ± 10.8 years).

FIELD STRENGTH/SEQUENCE

3.0T; TurboFlash, balanced steady-state free precession cine, and phase-sensitive inversion recovery sequences.

ASSESSMENT

Stress-MRI was used to obtain qualitative and quantitative parameters of segmental myocardium. Myocardial segments supplied by CTO target vessels were grouped according to the degree of collateral circulation assessed by radiographic coronary angiography (no/mild, moderate, or good). Depending on qualitative stress perfusion assessment and late gadolinium enhancement (LGE) extent, segments were also categorized as negative, viable, or trans-infarcted.

STATISTICAL TESTS

Independent sample Student's t-test, one-way analysis of variance (ANOVA) test, Mann-Whitney U test, Kruskal-Wallis test, Spearman correlation coefficient (r). P < 0.05 was considered statistically significant.

RESULTS

A total of 334 segments were supplied by CTO target vessels. The radial strain (RS), circumferential strain (CS), longitudinal strain (LS) of the negative, viable, and trans-infarcted regions showed a significant and stepwise impairment. Myocardial blood flow at rest was positively correlated with RS, CS, and LS (r = 0.42, 0.43, 0.38, respectively). Among the different collateral circulation, there were no significant differences in RS, CS, LS, and LGE volume (P = 0.788, 0.562, 0.122, 0.170, respectively), and there were also no statistically significant differences in the proportions of negative, viable, and trans-infarcted regions (P = 0.372).

DATA CONCLUSION

Myocardial perfusion obtained by stress-MRI combined with strain and LGE may comprehensively evaluate myocardial function and viability, and has potential to facilitate risk stratification of CTO.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 1.

Chronic Total Occlusion is Not a Risk Factor for Mortality in Patients With Successful Percutaneous Coronary Intervention: A Cohort Study

Background Fifteen percent of patients with coronary artery disease undergoing angiography have a chronic total occlusion (CTO). The current study aimed to investigate the long-term prognosis after successful and unsuccessful CTO percutaneous coronary intervention (PCI) compared with PCI for non-CTO lesions. Methods and Results The current study was designed as an observational, region-wide, register-based cohort study enrolling all patients undergoing PCI in the Central Region of Denmark in 2009 to 2019. Patients were stratified into non-CTO, successful CTO, and unsuccessful CTO revascularization. Patients were followed until an event or January 1, 2022. The primary end point was all-cause mortality. In 21 141 patients enrolled, 2108 underwent CTO PCI. Clinical presentation was acute coronary syndrome in 11 879 patients and chronic coronary syndrome in 7887 patients. After a median of 5.7 years (interquartile range, 3.3-8.8), long-term all-cause mortality was higher after CTO PCI compared with non-CTO PCI, but the difference was statistically insignificant when adjusting for clinical factors (unadjusted hazard ratio [HR], 1.19 [95% CI, 1.09-1.29], adjusted HR, 1.08 [95% CI, 0.97-1.20]; P=0.165). After successful CTO PCI, no difference compared with non-CTO PCI was observed (unadjusted HR, 0.99 [95% CI, 0.90-1.10], adjusted HR, 0.99 [95% CI, 0.87-1.12]; P=0.873). After unsuccessful CTO PCI, long-term all-cause mortality was higher than non-CTO PCI (unadjusted HR, 1.82 [95% CI, 1.59-2.08], adjusted HR, 1.35 [95% CI, 1.13-1.63]; P<0.001). Conclusions Patients undergoing PCI for CTO have elevated long-term mortality compared with patients without CTO. Successful opening of the CTO(s) is associated with equal mortality compared with non-CTO PCI. In contrast, failed CTO PCI is associated with worse long-term mortality. These findings suggest the need for CTO programs with high success rates and low complication rates.

SerpinG1: A Novel Biomarker Associated With Poor Coronary Collateral in Patients With Stable Coronary Disease and Chronic Total Occlusion

Background This study aimed to explore predictive biomarkers of coronary collateralization in patients with chronic total occlusion. Methods and Results By using a microarray expression profiling program downloaded from the Gene Expression Omnibus database, weighted gene coexpression network analysis was constructed to analyze the relationship between potential modules and coronary collateralization and screen out the hub genes. Then, the hub gene was identified and validated in an independent cohort of patients (including 299 patients with good arteriogenic responders and 223 patients with poor arteriogenic responders). Weighted gene coexpression network analysis showed that SERPING1 in the light-cyan module was the only gene that was highly correlated with both the gene module and the clinical traits. Serum levels of serpinG1 were significantly higher in patients with bad arteriogenic responders than in patients with good arteriogenic responders (472.53±197.16 versus 314.80±208.92 μg/mL; P<0.001) and were negatively associated with the Rentrop score (Spearman r=-0.50; P<0.001). Receiver operating characteristic curve analysis indicated that the area under the curve was 0.77 (95% CI, 0.72-0.81; P<0.001) for serum serpinG1 in prediction of bad arteriogenic responders. After adjusting for traditional cardiovascular risk factors, serum serpinG1 levels (per SD) remained an independent risk factor for bad arteriogenic responders (odds ratio, 2.20 [95% CI, 1.76-2.74]; P<0.001). Conclusions Our findings illustrate that SERPING1 screened by weighted gene coexpression network analysis was associated with poor collateralization in patients with chronic total occlusion.

The Comparison of Long-Term Outcome Between Patients with Single and Multiple Coronary Chronic Total Occlusions After Percutaneous Coronary Intervention

Background

Rapid advancements in percutaneous coronary intervention (PCI) have improved the outcome of chronic coronary total occlusions (CTOs); however, data regarding the difference in long-term outcomes in stable coronary artery disease (CAD) patients with single and multiple CTOs who underwent PCI are scarce. This study aimed to compare the long-term outcomes of patients with multiple CTOs and single CTO after PCI.

Methods

This study cohort included stable CAD patients who were diagnosed with CTO and treated with PCI from a single center. The primary endpoint was all-cause death.

Results

We retrospectively reviewed 670 consecutive patients with CTO-PCI. Among them, 539 patients had a single CTO, and 131 (19.7%) patients had multiple (at least two) CTOs. CTO revascularization was achieved in 470 (70.1%) patients. After a median follow-up duration of 33.7 months, the cumulative all-cause mortality (p = 0.037) and cardiac mortality (p = 0.003) were higher in patients with multiple CTOs than in those with a single CTO. In the multivariable model, multiple CTOs and left ventricular ejection fraction (LVEF) less than 40% were independent predictors for cardiac death (adjusted hazard ratio (HR) 2.53; P = 0.013 and adjusted HR 3.95; P < 0.001), while age older than 65 and LVEF less than 40% were independent predictors for all-cause death in CTO-PCI patients (adjusted hazard ratio (HR) 1.84; P = 0.035 and adjusted HR 2.54; P = 0.001).

Conclusion

In CTO-PCI patients, long-term survival was associated with multiple CTOs, age and LVEF, but not with CTO revascularization.