Update on the Management of Chronic Total Occlusions in Coronary Artery Disease

Impact of coronary collateralization on major adverse cardiovascular and cerebrovascular events after successful recanalization of chronic total occlusion

Aims

This study aims to investigate the effects of coronary collateral circulation (CCC) on the prognosis of chronic total occlusion (CTO) patients with or without metabolic syndrome (MetS).

Methods

The study included 342 CTO patients who underwent successful percutaneous coronary intervention at the People's Hospital of Liaoning Province between 1 February 2021 and 30 September 2023. The Rentrop score was used to assess the status of CCC. The outcome was major adverse cardiovascular and cerebrovascular events (MACCEs), defined as a composite of all-cause mortality, cardiac death, non-fatal myocardial infarction (MI), target vessel revascularization (TVR), and non-fatal stroke. Univariate and multivariate logistic analyses were used to investigate the association of CCC, MetS, and MACCEs with odds ratios (ORs) and 95% confidence intervals (CIs). The effect of CCC was further investigated in different MetS, diabetes mellitus (DM), and Syntax score groups.

Results

MACCEs were more common in patients with poor CCC compared to those with good CCC (38.74% vs. 16.56%). Statistical differences were found in MACCEs (OR = 3.33, 95% CI: 1.93-5.72), MI (OR = 3.11, 95% CI: 1.73-5.58), TVR (OR = 3.06, 95% CI: 1.70-5.53), and stent thrombosis (OR = 6.14, 95% CI: 2.76-13.65) between the good and poor CCC groups. Poor CCC patients with MetS had a higher incidence of MACCEs (OR = 4.21, 95% CI: 2.05-8.65), non-fatal MI (OR = 4.44, 95% CI: 2.01-9.83), TVR (OR = 3.28, 95% CI: 1.51-7.11), and stent thrombosis (OR = 10.80, 95% CI: 3.11-37.54). Similar findings were also observed in CTO patients with DM and a Syntax score ≥23.

Conclusion

Poor CCC could increase the risk of MACCEs in CTO patients, particularly those with MetS, DM, and a Syntax score ≥23. Further prospective, multicenter studies are needed to validate our findings and to explore potential therapeutic interventions.

Predictive value of the neutrophil percentage-to-albumin ratio for coronary atherosclerosis severity in patients with CKD

BACKGROUND

The neutrophil percentage-to-albumin ratio (NPAR), which is defined as the percentage of neutrophils divided by the concentration of albumin, is a cost-effective and readily available biomarker of inflammation. This study aimed to evaluate the association between the NPAR and the severity of coronary atherosclerosis in patients with chronic kidney disease (CKD).

METHODS

A total of 280 CKD patients who underwent coronary angiography were retrospectively enrolled in this study. The severity of coronary atherosclerosis was evaluated using the Gensini score (GS). Patients were divided into low-, medium- and high-NPAR groups according to the tertiles of the NPAR values. Logistic regression analysis was conducted to analyze the relationship between the NPAR and the GS. The cutoff points for the sensitivity and specificity of the NPAR in predicting the GS were estimated via receiver operating characteristic (ROC) analysis.

RESULTS

There was a higher prevalence of coronary artery disease (CAD) among CKD patients with higher NPARs (P =0.041). More patients in the high-NPAR group had complex CAD (triple-vessel disease and/or left main coronary artery stenosis) and chronic total occlusion lesions, and more of these patients required revascularization therapy (P<0.05). Multivariate logistic regression analysis revealed a significant positive correlation between the NPAR and the severity of coronary stenosis (adjusted OR 2.68, 95% CI 1.25-5.76, p=0.012), particularly among female and older (age ≥65) patients. The ROC analysis indicated that the optimal cutoff value for the NPAR in predicting severe coronary artery stenosis (GS>60) in CKD patients was 1.91 (sensitivity 0.495, specificity 0.749), with an area under the curve (AUC) of 0.650 (95% CI 0.581-0.719, P<0.001). A subgroup analysis according to sex revealed that the NPAR exhibited stronger predictive value in female patients (AUC 0.730, 95% CI 0.643-0.817) than in male patients (AUC 0.565, 95% CI 0.460-0.670) (P<0.001), and the optimal cutoff value for the NPAR in female patients was 1.80 (sensitivity 0.667, specificity 0.705).

CONCLUSIONS

Our study demonstrated that the NPAR is independently associated with the severity of coronary atherosclerosis in CKD patients, especially in female and elderly patients (≥65 years old). Moreover, the NPAR can effectively predict the severity of coronary atherosclerosis, exhibiting greater predictive value in females than in males.

Gender-Based Differences in Outcomes After Percutaneous Coronary Intervention of Chronic Total Occlusions (Insights from a Large Single-Center Registry)

Patients who undergo percutaneous coronary intervention (PCI) of chronic total occlusions (CTO) are at a high risk for both periprocedural and post-procedural adverse events. Whether gender-differences in outcomes exist after PCI of CTO remain unclear. Therefore, we sought to investigate gender-based differences in outcomes after CTO-PCI. All patients who underwent elective CTO intervention from January 2012 to December 2017 at The Mount Sinai Hospital (New York, New York) were included. The primary end point of interest was major adverse cardiac events defined as the composite of death, myocardial infarction, and target vessel revascularization at 1 year of follow-up. A total 1,897 patients were included, of which 368 were women (19.4%). Mean follow-up time was 174 days. Women were older (66.8 ± 11.3 years vs 62.6 ± 10.9 years) and had a higher prevalence of co-morbidities including diabetes and chronic kidney disease. There were no significant differences in the rate of successful CTO-PCI between groups (73.5% vs 73.2%, p = 0.91). Women had higher rates of procedure-related complications including increased risk of post-procedural bleeding (4.1% vs 1.8%, p = 0.009) and acute vessel closure (1.36% vs 0.2%, p = 0.009). In multivariable-adjusted analysis, female gender was associated with higher risk of major adverse cardiac event and target vessel revascularization at 1 year. In conclusion, in this large single-center study, women who underwent percutaneous CTO revascularization experienced higher rates of periprocedural complications and worse clinical outcomes at 1 year compared with men. Further research is needed to address disparities in gender-specific outcomes of CTO-PCI.

Prognostic Value of Different Levels of Uric Acid in Patients with Coronary Chronic Total Occlusion Undergoing Percutaneous Coronary Intervention

Recent data suggest that uric acid (UA) might be an independent predictor of clinical outcomes following percutaneous coronary intervention (PCI). The predictive value of uric acid in patients undergoing PCI for chronic total occlusions (CTO) is unknown. We included patients with CTO who underwent PCI at our center in 2005 and 2012, with available uric acid levels before angiography. Subjects were divided into groups according to uric acid tertiles (<5.5 mg/dL, 5.6-6.9 mg/dL, and >7.0 mg/dL), and outcomes were compared among the groups. Out of the 1963 patients (mean age 65.2 ± 11 years), 34.7% (n = 682) had uric acid concentrations in the first tertile, 34.3% (n = 673) in the second tertile, and 31% (n = 608) in the third tertile. Median follow-up was 3.0 years. Uric acid levels in the first tertile were associated with significantly lower all-cause mortality, as compared to the third tertile, with an adjusted hazard ratio (HR) of 0.67 (95% confidence interval (CI): 0.49 to 0.92; p = 0.012). No significant differences regarding all-cause mortality were found between patients in the first and second tertiles (HR: 0.96 [95% CI: 0.71 to 1.3; p = 0.78]). High levels of uric acid emerged as an independent predictor of all-cause mortality in patients with chronic total occlusion treated with PCI. Hence, uric acid levels should be incorporated into the risk assessment of patients with CTO.

Impact of impaired renal function on outcomes of chronic total occlusion undergoing revascularization: a systemic review and meta-analysis

PURPOSE

Patients with chronic kidney disease (CKD) have an associated burden of coronary artery disease, including chronic total occlusions (CTO). It is unclear how the presence of CKD affects the outcomes of CTO revascularization. Previous reviews have not taken into account all relevant published studies that examined the association of CKD with outcomes of CTO revascularization.

METHODS

A systematic search was conducted using PubMed, Scopus, and Google Scholar databases for studies investigating patients with or without CKD who also had coronary chronic total occlusion undergoing revascularization procedures Statistical analysis was performed using STATA software. Effect sizes were reported as pooled relative risk (RR).

RESULTS

A total of 13 studies were included. CKD patients showed elevated risk of in-hospital mortality (RR 4.25, 95% CI 2.64, 6.82) and mortality at latest follow-up (RR 3.24, 95% CI 2.56, 4.11), elevated risk of major cardio or cerebrovascular events (RR 1.65, 95% CI 1.38, 1.98), major bleeding (RR 2.85, 95% CI 1.96, 4.13), and contrast-induced acute kidney injury (RR 3.06, 95% CI 1.70, 5.52). CKD patients also showed lower chances of technical success (RR 0.95, 95% CI 0.91, 1.00).

CONCLUSIONS

The presence of CKD increases the risk of mortality, complications and adversely affects the success of CTO revascularization. Patients with CKD undergoing revascularization should have their kidney function comprehensively evaluated and these patients should be carefully monitored.

Guide-Wired Helical Microrobot for Percutaneous Revascularization in Chronic Total Occlusion in-Vivo Validation

OBJECTIVE

For the revascularization in small vessels such as coronary arteries, we present a guide-wired helical microrobot mimicking the corkscrew motion for mechanical atherectomy that enables autonomous therapeutics and minimizing the radiation exposure to clinicians.

METHODS

The microrobot is fabricated with a spherical joint and a guidewire. A previously developed external electromagnetic manipulation system capable of high power and frequency is incorporated and an autonomous guidance motion control including driving and steering is implemented in the prototype. We tested the validity of our approach in animal experiments under clinical settings. For the in vivo test, artificial thrombus was fabricated and placed in a small vessel and atherectomy procedures were conducted.

RESULTS

The devised approach enables us to navigate the helical robot to the target area and successfully unclog the thrombosis in rat models in vivo.

CONCLUSION

This technology overcomes several limitations associated with a small vessel environment and promises to advance medical microrobotics for real clinical applications while achieving intact operation and minimizing radiation exposures to clinicians.

SIGNIFICANCE

Advanced microrobot based on multi-discipline technology could be validated in vivo for the first time and that may foster the microrobot application at clinical sites.

Management of Percutaneous Coronary Intervention Complications: Algorithms From the 2018 and 2019 Seattle Percutaneous Coronary Intervention Complications Conference

Complications of percutaneous coronary intervention (PCI) may have significant impact on patient survival and healthcare costs. PCI procedural complexity and patient risk are increasing, and operators must be prepared to recognize and treat complications, such as perforations, dissections, hemodynamic collapse, no-reflow, and entrapped equipment. Unfortunately, few resources exist to train operators in PCI complication management. Uncertainty regarding complication management could contribute to the undertreatment of patients with high-complexity coronary disease. We, therefore, coordinated the Learning From Complications: How to Be a Better Interventionalist courses to disseminate the collective experience of high-volume PCI operators with extensive experience in chronic total occlusion and high-risk PCI. From these conferences in 2018 and 2019, we developed algorithms that emphasize early recognition, effective treatment, and team-based care of PCI complications. We think that an algorithmic approach will result in a logical and systematic response to life-threatening complications. This construct may be useful for operators who plan to perform complex PCI procedures.

Percutaneous Coronary Intervention Versus Medical Therapy for Chronic Total Occlusion of Coronary Arteries: A Systematic Review and Meta-Analysis

Purpose of Review

Chronic total occlusion (CTO) of the coronary arteries is a significant clinical problem and has traditionally been treated by medical therapy or coronary artery bypass grafting. Recent studies have examined percutaneous coronary intervention (PCI) as an alternative option.

Recent Findings

This systematic review and meta-analysis compared medical therapy to PCI for treating CTOs.

Summary

PubMed and Embase were searched from their inception to March 2019 for studies that compared medical therapy and PCI for clinical outcomes in patients with CTOs. Quality of the included studies was assessed by Newcastle–Ottawa scale. The results were pooled by DerSimonian and Laird random- or fixed-effect models as appropriate. Heterogeneity between studies and publication bias was evaluated by I² index and Egger’s regression, respectively. Of the 703 entries screened, 17 studies were included in the final analysis. This comprised 11,493 participants. Compared to PCI, medical therapy including randomized and observational studies was significantly associated with higher risk of all-cause mortality (risk ratio (RR) 1.99, 95% CI 1.38–2.86), cardiac mortality (RR 2.36 (1.97–2.84)), and major adverse cardiac event (RR 1.25 (1.03–1.51)). However, no difference in the rate of myocardial infarction and repeat revascularization procedures was observed between the two groups. Univariate meta-regression demonstrated multiple covariates as independent moderating factors for myocardial infarction and repeat revascularization but not cardiac death and all-cause mortality. However, when only randomized studies were included, there was no difference in overall mortality or cardiac death. In CTO, when considering randomized and observational studies, medical therapy might be associated with a higher risk of mortality and myocardial infarction compared to PCI treatment.

Electronic supplementary material

The online version of this article (10.1007/s11883-019-0804-8) contains supplementary material, which is available to authorized users.

Sex-Based Differences in Chronic Total Occlusion Management

ᅟ: Chronic total occlusions (CTOs) are an important and increasingly recognized subgroup of coronary lesions, documented in at least 30%, but up to 52% of patients with coronary artery disease (CAD) undergoing coronary angiography. Percutaneous coronary intervention (PCI) of these lesions is increasingly pursued, with excellent success rates. PURPOSE OF REVIEW: It is known that gender differences exist in the presentation of CAD, as well as in clinical outcomes after routine PCI; however, it is not well described how these differences pertain to management of CTOs. This review summarizes the available data regarding sex-based differences in CTO management and outcomes. RECENT FINDINGS: Women comprise approximately 20% of CTO registry and trial participants. As has been demonstrated in PCI studies, women comprise a minority of patients in CTO PCI registries and trials. Sex-based differences exist in complication rates, collateral formation, and outcomes and need further evaluation in future studies.

A Magnetically Controlled Soft Microrobot Steering a Guidewire in a Three-Dimensional Phantom Vascular Network

Magnetically actuated soft robots may improve the treatment of disseminated intravascular coagulation. Significant progress has been made in the development of soft robotic systems that steer catheters. A more challenging task, however, is the development of systems that steer sub-millimeter-diameter guidewires during intravascular treatments; a novel microrobotic approach is required for steering. In this article, we develop a novel, magnetically actuated, soft microrobotic system, increasing the steerability of a conventional guidewire. The soft microrobot is attached to the tip of the guidewire, and it is magnetically steered by changing the direction and intensity of an external magnetic field. The microrobot is fabricated via replica molding and features a soft body made of polydimethylsiloxane, two permanent magnets, and a microspring. We developed a mathematical model mapping deformation of the soft microrobot using a feed-forward approach toward steering. Then, we used the model to steer a guidewire. The angulation of the microrobot can be controlled from 21.1° to 132.7° by using a magnetic field of an intensity of 15 mT. Steerability was confirmed by two-dimensional in vitro tracking. Finally, a guidewire with the soft microrobot was tested by using a three-dimensional (3D) phantom of the coronary artery to verify steerability in 3D space.