Approach to CTO Intervention: Overview of Techniques

Heart and great vessels segmentation in congenital heart disease via CNN and conditioned energy function postprocessing

PURPOSE

The segmentation of the heart and great vessels in CT images of congenital heart disease (CHD) is critical for the clinical assessment of cardiac anomalies and the diagnosis of CHD. However, the diverse types and abnormalities inherent in CHD present significant challenges to comprehensive heart segmentation.

METHODS

We proposed a novel two-stage segmentation approach, integrating a Convolutional Neural Network (CNN) with a postprocessing method with conditioned energy function for pulmonary and aorta. The initial stage employs a CNN enhanced by a gated self-attention mechanism for the segmentation of five primary heart structures and two major vessels. Subsequently, the second stage utilizes a conditioned energy function specifically tailored to refine the segmentation of the pulmonary artery and aorta, ensuring vascular continuity.

RESULTS

Our method was evaluated on a public dataset including 110 3D CT volumes, encompassing 16 CHD variants. Compared to prevailing segmentation techniques (U-Net, V-Net, Unetr, dynUnet), our approach demonstrated improvements of 1.02, 1.04, and 1.41% in Dice Coefficient (DSC), Intersection over Union (IOU), and the 95th percentile Hausdorff Distance (HD95), respectively, for heart structure segmentation. For the two great vessels, the enhancements were 1.05, 1.07, and 1.42% in these metrics.

CONCLUSION

The outcomes on the public dataset affirm the efficacy of our proposed segmentation method. Precise segmentation of the entire heart and great vessels can significantly aid in the diagnosis and treatment of CHD, underscoring the clinical relevance of our findings.

Antegrade Crossing Techniques for Hard Proximal Occlusion Caps Without the Use of Dedicated Chronic Total Occlusion Devices: A Pictorial Review

CLINICAL IMPACT

Infra-inguinal Chronic Total Occlusions recanalisation is considered technically challenging. The conventional manipulation of standard guidewires and catheters has proven to be successful in a considerable percentage of cases but success rate could dramatically drop in presence of challenging lesions. The additional use of retrograde access and re-entry devices could increase technical success but could negatively affect procedural time and overall costs. Twenty different techniques of Chronic Total Occlusions antegrade crossing are hereby described with appropriate schematic representations. The aim is to help operators to apply them in specific anatomy subsets and clinical presentations and ultimately to increase procedural success rate.

Reduced cerebral vascular fractal dimension among asymptomatic individuals as a potential biomarker for cerebral small vessel disease

Cerebral small vessel disease is a neurological disease frequently found in the elderly and detected on neuroimaging, often as an incidental finding. White matter hyperintensity is one of the most commonly reported neuroimaging markers of CSVD and is linked with an increased risk of future stroke and vascular dementia. Recent attention has focused on the search of CSVD biomarkers. The objective of this study is to explore the potential of fractal dimension as a vascular neuroimaging marker in asymptomatic CSVD with low WMH burden. D_f is an index that measures the complexity of a self-similar and irregular structure such as circle of Willis and its tributaries. This exploratory cross-sectional study involved 22 neurologically asymptomatic adult subjects (42 ± 12 years old; 68% female) with low to moderate 10-year cardiovascular disease risk prediction score (QRISK2 score) who underwent magnetic resonance imaging/angiography (MRI/MRA) brain scan. Based on the MRI findings, subjects were divided into two groups: subjects with low WMH burden and no WMH burden, (WMH⁺; n = 8) and (WMH⁻; n = 14) respectively. Maximum intensity projection image was constructed from the 3D time-of-flight (TOF) MRA. The complexity of the CoW and its tributaries observed in the MIP image was characterised using D_f. The D_f of the CoW and its tributaries, i.e., D_f (w) was significantly lower in the WMH⁺ group (1.5172 ± 0.0248) as compared to WMH⁻ (1.5653 ± 0.0304, p = 0.001). There was a significant inverse relationship between the QRISK2 risk score and D_f (w), (r_s = − .656, p = 0.001). D_f (w) is a promising, non-invasive vascular neuroimaging marker for asymptomatic CSVD with WMH. Further study with multi-centre and long-term follow-up is warranted to explore its potential as a biomarker in CSVD and correlation with clinical sequalae of CSVD.

Angiographic Characteristics and Outcomes of Percutaneous Coronary Intervention of Reattempted Chronic Total Occlusion: Potential Contributing Factors to Procedural Success

This study aimed to analyze angiographic characteristics of new attempted percutaneous coronary intervention (PCI) on chronic total occlusion (CTO) compared to first attempt group. The cohort of 527 CTO-PCIs was divided into first-attempt and re-attempt groups, and angiographic characteristics, level of complexity, and contributing factors to failure were analyzed. Between-group success rate difference and potential angiographic and technical aspects contributing to the success in new attempts were scrutinized. A total of 47 new PCIs in 39 patients were performed. The reattempt group showed higher J-CTO score compared to the first-attempt group (2.4 ± 1.06 vs. 1.2 ± 1.06; p < 0.001). The use of more complex techniques and devices such as retrograde approach (29.8% vs. 12.9%) and IVUS (48.9 vs. 27.3%; p: 0.002) were more frequent in the reattempt group. Both procedural and fluoroscopy time were higher in the reattempt group (197 ± 83.9 vs. 150.1 ± 72.3 and 97.7 ± 55.4 vs. 68.7 ± 43, respectively; p < 0.001). There was no between-group difference in terms of technical success (79.8 vs. 76.6% for first attempt vs. reattempt group, respectively; p: 0.6). The overall success rate increased by 6.1%, achieving 85.9% in the entire cohort. Reattempted CTO-PCIs required more complex techniques and had comparable technical success rate with regard to the first-attempt group.

The Canadian Contribution to Science, Techniques, Technology, and Education in Chronic Total Occlusion Percutaneous Coronary Intervention

Chronic total occlusions are considered the most complex coronary lesions in interventional cardiology. This article reviews the Canadian clinical and academic contributions to this field, including innovative procedural techniques, teaching and proctoring, clinical research, and the development of novel tools and therapies.

Rational guidewire use in the coronary chronic total occlusion interventions

Background

Procedures for coronary chronic total occlusion (CTO) are still a clinical challenge with relatively lower success rates. Recent advances in the biotechnology and introduction of CTO-dedicated guidewires have increased the procedural success rate of CTO interventions. Herein, we aimed to reveal the clinical and angiographic predictors of the crossability of the initial guidewire choice and rational guidewire usage in CTO interventions. A total of 177 patients with an indication for a coronary CTO procedure were included in this study. The use of 1–3 guidewires and crossing of the CTO lesion with the initial guidewire choice was defined as rational guidewire usage. The CTO lesions were classified according to the Japanese chronic total occlusion registry (J-CTO) and EuroCTO scores for evaluating the difficulty of the procedures. Then, a statistical analysis was performed to assess the initial guidewire choice, crossability, and contributors to rational guidewire usage.

Results

The mean J-CTO score was 1.42 ± 1.16, and the mean EuroCTO score was 1.44 ± 1.18. The success rate of the procedures was 90.4%. The initial guidewire choice crossed the lesion in 44.1% of the cases, in which 1–3 guidewires were used (82.1%). The crossability of the polymeric and moderate stiff tip guidewires was higher (82.1% and 64.1%, respectively), and the Pilot series was the most successful brand (36.2%). Logistic regression analysis confirmed that J-CTO score, procedural technique, guidewire type, and stiffness of the tip were the major predictors of rational guidewire usage.

Conclusion

Our analysis showed that the use of polymeric and moderate stiff tip guidewires, particularly the Pilot brand, were associated with rational guidewire usage in easy and intermediate difficulty CTO cases.

Simple Techniques for Antegrade Guiding Catheter Engagement after Retrograde CTO Crossing

Interventional treatment of chronic total occlusions (CTOs) is nowadays counting on a wide span of procedural possibilities, and retrograde approaches are becoming more and more frequent as they warrant high success rates at the cost of a slightly higher incidence of donor vessel damage. Retrograde lesion crossing needs to be followed by procedural conversion to an antegrade approach to dilate and stent the lesion, and new techniques are being proposed to address this issue and achieve a safer recanalization of the vessel. In this context, we propose novel and simple techniques to antegrade guiding catheter engagement by the retrograde wire, enhancing the chances for procedural success.

Long-term clinical effects of recanalization of chronic coronary total occlusions in patients with left ventricular systolic dysfunction

OBJECTIVES

The aim of the present analysis is to evaluate the clinical impact of chronic total occlusions (CTOs) recanalization in patients with left ventricular (LV) systolic dysfunction.

BACKGROUND

According to contemporary knowledge, patient selection for percutaneous CTO revascularization is not yet standardized. In particular, data on outcomes in patients with LV systolic dysfunction undergoing percutaneous coronary intervention (PCI) for CTO are scarce.

METHODS

From a total of 2,421 consecutive patients with at least one CTO, 436 patients with ejection fraction (EF) ≤45%, who were referred for coronary angiography between January 1998 and September 2014, were selected. Patients with successful recanalization of the target CTO were assigned to CTO-revascularized group and those with failed or not attempted recanalization to the CTO-not revascularized (CTO-NR) group. Study endpoints were all-cause death, cardiac death, and occurrence of myocardial infarction on follow-up.

RESULTS

Out of 436 CTO patients with reduced EF, 228 (52.3%) were successfully recanalized and 208 patients (47.7%) were not, either due to CTO-PCI failure (n = 106, 24.3%) or because CTO-PCI was not attempted (n = 102, 23.4%). At long-term follow-up, CTO-NR patients had significantly higher rate of overall (p = .021) and cardiac mortality (p = .035) compared to those successfully revascularized.

CONCLUSION

In patients with systolic LV dysfunction (EF ≤ 45%), CTO revascularization was associated with significant lower rate of total and cardiac mortality compared to those with nonrevascularized CTO.

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.

Examining the Operator Learning Curve for Percutaneous Coronary Intervention of Chronic Total Occlusions

Background:

Advances in chronic total occlusion percutaneous coronary intervention (CTO PCI) techniques have led to increased procedural success rates among operators. While utilization of CTO PCI has disseminated widely, the learning curve for new operators has not been well-defined.

Methods:

Between July 2009 and December 2015, 93 875 CTO PCI cases were extracted from the CathPCI Registry. We delineated a cohort of new CTO operators performing <10 CTO PCI cases per given year. In-hospital outcomes for subsequent CTO PCIs were stratified by the number of prior cases accrued by each operator. Multivariable regression models were used to estimate differences in outcomes with increasing experience. The primary outcome was major adverse cardiovascular events defined as the composite of death, myocardial infarction, stroke, tamponade, or urgent coronary artery bypass grafting.

Results:

Among 70 916 cases performed by 7251 new operators, procedure success rate was 61.4% and major adverse cardiovascular event rate was 4.2%. Meanwhile, the rate of major bleeding was 4.0%, myocardial infarction 2.0%, mortality 0.6%, tamponade 0.3%, and renal failure 0.2%. Adjusted regression models demonstrated piecewise linear improvements in guidewire crossing, stent placement, and procedure success with accrued volume, albeit with increased contrast use, fluoroscopy time, and bleeding. Major adverse cardiovascular event rates were stable beyond the 12th case (odds ratio per 5 case increase 1.00; 95% CI, 0.98–1.03, P =0.7980).

Conclusions:

Among a large number of new CTO PCI operators in the United States, there exists an experiential learning curve for procedural success. However, there were higher rates of bleeding despite case experience, while major adverse cardiovascular events remained relatively unchanged after initiation.

Dual lumen microcatheters for complex percutaneous coronary interventions

In some bifurcation anatomies side branch wiring can be difficult particularly when side branch is highly angulated. Furthermore a combination of bifurcations and chronic total occlusion can be a real challenge for interventional cardiologists. New devices have been produced to facilitate complex PCI and recently introduced dual lumen microcatheters can be really helpful in these scenarios. All these devices have both a rapid-exchange and an over-the-wire lumen. The rationale for dual lumen microcatheters is to preserve the highest number of side-branches. Nevertheless PCI should always aim to the most complete revascularization and to the lowest rate of side-branch loss. The purpose of this review is to describe current available dual lumen microcatheters, interventional scenarios in which their use may be helpful and basics of their proper use.