The differences between neovascularization of chronic total occlusion and intraplaque angiogenesis

Leveraging Machine Learning Techniques to Forecast Chronic Total Occlusion before Coronary Angiography

BACKGROUND

Chronic total occlusion (CTO) remains the most challenging procedure in coronary artery disease (CAD) for interventional cardiology. Although some clinical risk factors for CAD have been identified, there is no personalized prognosis test available to confidently identify patients at high or low risk for CTO CAD. This investigation aimed to use a machine learning algorithm for clinical features from clinical routine to develop a precision medicine tool to predict CTO before CAG.

METHODS

Data from 1473 CAD patients were obtained, including 1105 in the training cohort and 368 in the testing cohort. The baseline clinical characteristics were collected. Univariate and multivariate logistic regression analyses were conducted to identify independent risk factors that impact the diagnosis of CTO. A CTO predicting model was established and validated based on the independent predictors using a machine learning algorithm. The area under the curve (AUC) was used to evaluate the model.

RESULTS

The CTO prediction model was developed with the training cohort using the machine learning algorithm. Eight variables were confirmed as 'important': gender (male), neutrophil percentage (NE%), hematocrit (HCT), total cholesterol (TC), high-density lipoprotein cholesterol (HDL), ejection fraction (EF), troponin I (TnI), and N-terminal pro-B-type natriuretic peptide (NT-proBNP). The model achieved good concordance indices of 0.724 and 0.719 in the training and testing cohorts, respectively.

CONCLUSIONS

An easy-to-use tool to predict CTO in patients with CAD was developed and validated. More research with larger cohorts are warranted to improve the prediction model, which can support clinician decisions on the early discerning CTO in CAD patients.

Primary Percutaneous Coronary Intervention in Patients With Type 2 Diabetes With Late/Very Late Stent Thrombosis and de novo Lesions: A Single-Center Observational Cohort Study of Clinical Outcomes and Influencing Factors

Background: This study compared differences in the risk factors and clinical outcomes of primary percutaneous coronary intervention (PCI) in type 2 diabetes mellitus (DM) and non-DM patients with de novo lesions (DNLs) and late or very late stent thrombosis (LST/VLST).

Methods: We used angiography to screen 4,151 patients with acute coronary syndrome for DNL and LST/VLST lesions. Overall, 3,941 patients were included in the analysis and were allocated to the DM (n = 1,286) or non-DM (n = 2,665) group at admission. The primary endpoint was a composite of major adverse cardiovascular events (MACEs), defined as death, myocardial infarction, revascularization, and ischemic stroke, within a median follow-up period of 698 days.

Results: In the group with a total white blood cell count >10 × 10⁹/L (P = 0.004), a neutral granular cell count >7 × 10⁹/L (P = 0.030), and neutrophil–lymphocyte ratio >1.5 (P = 0.041), revascularization was better for DNL than for LST/VLST lesions. Among DM patients with DNLs, each unit increase in age was associated with a 53.6% increase in the risk of MACEs [hazard ratio (HR): 1.536, 95% confidence interval (CI), 1.300–1.815, P < 0.0001]. Older age (≥65 years) was associated with a significantly greater risk of MACEs (P < 0.0001). Furthermore, each standard deviation (SD) increase in the level of peak white blood cell counts was associated with a 50.1% increase in the risk of MACEs (HR, 1.501; 95% CI, 1.208–1.864; P = 0.0002). When stratifying the DM population with DNLs according to the D-dimer baseline and peak levels <0.5 vs. ≥0.5 mg/L, the high D-dimer group at baseline had a 2.066-fold higher risk of MACEs (P < 0.0001), and the high peak level D-dimer group had a 1.877-fold higher risk of MACEs (P = 0.001) compared to the low-level groups. Among DM patients with LST/VLST, each unit increase in age was associated with a 75.9% increase in the risk of MACEs (HR: 1.759, 95% CI, 1.052–2.940, P = 0.032). Furthermore, for each SD increase in the peak D-dimer level, the risk of MACEs increased by 59.7% (HR, 1.597; 95% CI, 1.110–2.295; P = 0.041).

Conclusion: Following successful primary PCI, the measurement of baseline and peak D-dimer values may help identify individuals at high cardiovascular risk. This suggests a potential benefit of lowering D-dimer levels among T2DM patients with DNL. Furthermore, age and the peak D-dimer values may facilitate the risk stratification of T2DM patients with LST/VLST.

Identification of micro-channels within chronic total occlusions using contrast-enhanced ultrasound

BACKGROUND

Vascular micro-channels within chronic total occlusions (CTO) have been identified in histopathology and animal studies. They have been proposed as a potential path for achieving endovascular crossing via the lumen. There are currently no noninvasive means of imaging these structures. The aim of this study was to investigate whether contrast-enhanced ultrasound (CEUS) examination can identify micro-channels within CTO in humans.

METHODS

CTO within the femoropopliteal arteries were imaged with CEUS examination in 38 patients. Segments containing micro-channels were identified and their length measured. The proportion of occlusion length containing micro-channels was assessed for each case. Micro-channel appearances including linear or tortuous configuration, crossing of occlusion caps, and connections to vasa vasorum were recorded.

RESULTS

The median CTO length was 17.0 cm (interquartile range [IQR], 6.9-27.9 cm) and median age of CTO was 12 months (IQR, 6-16 months). Micro-channels were identified in 92.1% of cases (35/38). The median length within a lesion containing micro-channels was 6.4 cm (IQR, 2.4-14.3 cm) and median proportion of CTO containing micro-channels was 47.9% (IQR, 1.7%-28.5%). A linear micro-channel configuration was seen in 84.2% of cases and a tortuous configuration was seen in 57.9% of cases. Micro-channel connections through the cap were seen in 50% (19/38 cases) and connections to the vasa vasorum in 71.1% (27/38 cases). No association was found between the proportion of each lesion containing micro-channels and CTO age, lesion length or calcification severity. There were no adverse effects related to contrast use.

CONCLUSIONS

CEUS can be used to detect micro-channels in CTO in human femoropopliteal arteries. This imaging technique is safe and minimally invasive and may represent a practical method for selection of occlusion crossing method. Further work is required to determine whether identification of micro-channels can be used to improve treatment decision-making and provide a better understanding of the natural history of femoropopliteal CTO.

Effect of Breviscapine on Recovery of Viable Myocardium and Left Ventricular Remodeling in Chronic Total Occlusion Patients After Revascularization: Rationale and Design for a Randomized Controlled Trial

BACKGROUND How to speed the recovery of viable myocardium in chronic total occlusion (CTO) patients after revascularization is still an unsolved problem. Breviscapine is widely used in cardiovascular diseases. However, there has been no study focused on the effect of breviscapine on viable myocardium recovery and left ventricular remodeling after CTO revascularization. MATERIAL AND METHODS We propose to recruit 78 consecutive coronary artery disease (CAD) patients with CTO during a period of 12 months. They will be randomly assigned to receive either breviscapine (40 mg) or placebo in the following 12 months. Blood tests, electrocardiogram, and Major Adverse Cardiac Events (MACE) will be collected at baseline and the follow-up visits at 1, 3, 6, 9, and 12 months. Low-dose dobutamine MRI will be applied for the assessment of viable myocardium, microcirculation perfusion, and left ventricular remodeling, and the concentrations of angiogenic cytokine, vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) will be investigated at baseline and at 1- and 12-month follow-up. The recovery of viable myocardium after revascularization in CTO patients was the primary endpoint. Improvement of microcirculation perfusion, left ventricular remodeling, peripheral concentrations of VEGF and bFGF as well as MACE will be the secondary endpoints. RESULTS Breviscapine treatment obviously improve the recovery of viable myocardium, myocardial microcirculation perfusion, and left ventricular remodeling after revascularization in CTO patients, and reduce the occurrence of MACE. We also will determine if breviscapine increases the peripheral blood angiogenic cytokine concentrations of VEGF and bFGF. CONCLUSIONS This study will aim to demonstrate the effect of breviscapine on the recovery of viable myocardium and left ventricular remodeling in CTO patients after revascularization.

Use of cardiovascular age for assessing risks and benefits of menopausal hormone therapy

The Women's Health Initiative studies and others have suggested that menopausal hormone therapy may enhance the risk of new cardiovascular (CV) events in older women and diminish the development of coronary atherosclerosis in younger women. The underlying mechanisms to explain these findings are encapsulated in the term "Timing Hypothesis." Extensive pathophysiologic studies have provided mechanistic evidence for the dichotomous effects of estrogen on coronary artery vasculature. Early in the atherosclerotic disease process, estrogen exerts protective effects on the endothelium and retards plaque formation. Late in the process, estrogen causes plaque erosion or rupture with subsequent thrombosis and acute coronary events. Analysis of the Timing Hypothesis in women examined in the Women's Health Initiative primarily used chronologic age to assess divergent effects of estrogen. The complexity of the data underlying coronary pathophysiology has resulted in controversy whether MHT can be used in older women or those with prior CV disease. In a debate of this issue at a recent International Menopause Society meeting, the concept of using CV age rather than chronologic age was discussed as a practical method of resolving this issue and facilitating therapeutic decisions in older women. This "Personal Perspective" will review the concepts underlying CV age, describe how it is determined, provide support for its utility, and propose future studies using this parameter.

Impact of Neutrophil to Lymphocyte Ratio (NLR) Index and Its Periprocedural Change (NLRΔ) for Percutaneous Coronary Intervention in Patients With Chronic Total Occlusion

We assessed the association between neutrophil to lymphocyte ratio (NLR) and chronic coronary total occlusion (CTO), as well as clinical prognosis of percutaneous coronary intervention (PCI). Patients referred for elective coronary angiography for stable angina pectoris were enrolled, including a CTO (n = 160) and a non-CTO group (n = 160). Neutrophil to lymphocyte ratio on admission and post-PCI was measured, and NLR_Δ was defined as the change between the 2 values. Subgroup analysis was performed based on the value of NLR_Δ (≥0.5 vs <0.5). Clinical characteristics, angiographic data, and follow-up data were recorded. Compared with the non-CTO group, the total white blood cell count, neutrophil counts, and NLR were significantly higher in the CTO group. In the NLR_Δ ≥ 0.5 subgroup, the incidence of severe dissection, slow coronary flow, in-stent restenosis (ISR), and major adverse cardiac events (MACEs) was obviously higher. In multivariate analysis, NLR_Δ was independently and positively associated with higher risks of ISR and MACE. The NLR could be a potential predictor of CTO, and NLR_Δ is independently associated with the adverse clinical outcomes in patients who underwent PCI.

Genetic loci on chromosome 5 are associated with circulating levels of interleukin-5 and eosinophil count in a European population with high risk for cardiovascular disease

IL-5 is a Th2 cytokine which activates eosinophils and is suggested to have an atheroprotective role. Genetic variants in the IL5 locus have been associated with increased risk of CAD and ischemic stroke. In this study we aimed to identify genetic variants associated with IL-5 concentrations and apply a Mendelian randomisation approach to assess IL-5 levels for causal effect on intima-media thickness in a European population at high risk of coronary artery disease. We analysed SNPs within robustly associated candidate loci for immune, inflammatory, metabolic and cardiovascular traits. We identified 2 genetic loci for IL-5 levels (chromosome 5, rs56183820, BETA=0.11, P=6.73E(-5) and chromosome 14, rs4902762, BETA=0.12, P=5.76E(-6)) and one for eosinophil count (rs72797327, BETA=-0.10, P=1.41E(-6)). Both chromosome 5 loci were in the vicinity of the IL5 gene, however the association with IL-5 levels failed to replicate in a meta-analysis of 2 independent cohorts (rs56183820, BETA=0.04, P=0.2763, I(2)=24, I(2)-P=0.2516). No significant associations were observed between SNPs associated with IL-5 levels or eosinophil count and IMT measures. Expression quantitative trait analyses indicate effects of the IL-5 and eosinophil-associated SNPs on RAD50 mRNA expression levels (rs12652920 (r2=0.93 with rs56183820) BETA=-0.10, P=8.64E(-6) and rs11739623 (r2=0.96 with rs72797327) BETA=-0.23, P=1.74E(-29), respectively). Our data do not support a role for IL-5 levels and eosinophil count in intima-media thickness, however SNPs associated with IL-5 and eosinophils might influence stability of the atherosclerotic plaque via modulation of RAD50 levels.

The relation between neutrophil-to-lymphocyte ratio and coronary chronic total occlusions

BACKGROUND

Neutrophil-to-lymphocyte ratio (NLR) is a marker of systemic inflammation that correlates with cardiac events. This study assessed the association between NLR and the presence of chronic coronary total occlusion (CTO).

METHODS

The study population included 225 patients, a control group (n = 75), a coronary artery disease group (n = 75), and a CTO group (n = 75). NLR was compared in the three groups.

RESULTS

NLR levels were significantly higher in the CTO than in the other two groups (p < 0.001). Bivariate correlation analysis showed a positive correlation between NLR and SYNTAX Score, and multivariate logistic regression analysis found that NLR was an independent predictor of CTO. ROC analysis showed that an NLR cut-off of 2.09 could distinguish between patients with and without CTO (AUC = 0.74; 95% CI, 0.68-0.81), with a specificity of 69.3% and a sensitivity of 61%.

CONCLUSION

NLR may be useful as a marker of CTO.

Difference of neointimal growth patterns in bifurcation lesions among four kinds of drug-eluting stents: an optical coherence tomographic study

AIM

Neointimal proliferation of bifurcation lesions after implantation of drug-eluting stents (DES) has not been well evaluated. Thus, we compared neointimal proliferation of bifurcation lesions among four DES using optical coherence tomography (OCT).

METHODS

8-month follow-up OCT was performed in 68 bifurcation lesions treated by 15 sirolimus-eluting stents (SES) and 17 paclitaxel-eluting stents (PES) as first-generation DES, and by 17 zotarolimus-eluting stents (ZES) and 19 everolimus-eluting stents (EES) as second-generation DES. Cross-sectional images of the bifurcation lesion using OCT were analyzed every 450 µm. All images were divided into three areas: inner wall of the bifurcation (IB), outer wall of the bifurcation (OB), and ostium of the side branch (SB). We compared the incidence of uncovered struts (IUS) among three areas and the averaged neointimal thickness (NIH) between IB and OB in each stent and also compared these OCT parameters among all DES.

RESULTS

There were no significant differences of IUS between IB and OB in second-generation DES, while in first-generation DES, IUS of IB and OB showed significant differences. The IUS of SES in both areas was significantly higher than in the other DES (all P < 0.001). PES had a significantly higher IUS in SB than the others (all P < 0.001). NIH of OB was significantly higher than that of IB in PES, ZES, and EES, but in SES the NIH was similar in the two areas.

CONCLUSIONS

OCT revealed different neointimal growth patterns among SES, PES, ZES, and EES in bifurcation lesions.

Rationale for Percutaneous Intervention of CTO

Chronic total occlusion accounts for 15% of cases during diagnostic angiography with higher referral rate to surgical revascularization. With contemporary strategies and techniques, the success rate with experienced operators can exceed 90%. Currently available observational studies in carefully selected patient populations show evidence of a trend toward symptom relief; improvement in quality of life, left ventricular function, and mortality; and improved tolerance toward future ischemic events. Lack of randomized controlled trials comparing current optimal medical management with percutaneous coronary intervention for chronic total occlusion is a major barrier to widespread adaptation of this advanced complex interventional technique.

Comparative vascular responses three months after paclitaxel and everolimus-eluting stent implantation in streptozotocin-induced diabetic porcine coronary arteries

BACKGROUND

Diabetes remains a significant risk factor for restenosis/thrombosis following stenting. Although vascular healing responses following drug-eluting stent (DES) treatment have been characterized previously in healthy animals, comparative assessments of different DES in a large animal model with isolated features of diabetes remains limited. We aimed to comparatively assess the vascular response to paclitaxel-eluting (PES) and everolimus-eluting (EES) stents in a porcine coronary model of streptozotocin (STZ)-induced type I diabetes.

METHOD

Twelve Yucatan swine were induced hyperglycemic with a single STZ dose intravenously to ablate pancreatic β-cells. After two months, each animal received one XIENCE V® (EES) and one Taxus Liberte (PES) stent, respectively, in each coronary artery. After three months, vascular healing was assessed by angiography and histomorphometry. Comparative in vitro effects of everolimus and paclitaxel (10-5 M-10-12 M) after 24 hours on carotid endothelial (EC) and smooth muscle (SMC) cell viability under hyperglycemic (42 mM) conditions were assayed by ELISA. Caspase-3 fluorescent assay was used to quantify caspase-3 activity of EC treated with everolimus or paclitaxel (10-5 M, 10-7 M) for 24 hours.

RESULTS

After 3 months, EES reduced neointimal area (1.60 ± 0.41 mm, p < 0.001) with trends toward reduced % diameter stenosis (11.2 ± 9.8%, p = 0.12) and angiographic late-loss (0.28 ± 0.30 mm, p = 0.058) compared to PES (neointimal area: 2.74 ± 0.58 mm, % diameter stenosis: 19.3 ± 14.7%, late loss: 0.55 ± 0.53 mm). Histopathology revealed increased inflammation scores (0.54 ± 0.21 vs. 0.08 ± 0.05), greater medial necrosis grade (0.52 ± 0.26 vs. 0.0 ± 0.0), and persistently elevated fibrin scores (1.60 ± 0.60 vs. 0.63 ± 0.41) with PES compared to EES (p < 0.05). In vitro, paclitaxel significantly increased (p < 0.05) EC/SMC apoptosis/necrosis at high concentrations (≥ 10-7 M), while everolimus did not affect EC/SMC apoptosis/necrosis within the dose range tested. In ECs, paclitaxel (10-5 M) significantly increased caspase-3 activity (p < 0.05) while everolimus had no effect.

CONCLUSION

After 3 months, both DES exhibited signs of delayed healing in a STZ-induced diabetic swine model. PES exhibited greater neointimal area, increased inflammation, greater medial necrosis, and persistent fibrin compared to EES. Differential effects of everolimus and paclitaxel on vascular cell viability may potentially be a factor in regulating delayed healing observed with PES. Further investigation of molecular mechanisms may aid future development of stent-based therapies in treating coronary artery disease in diabetic patients.