Language of CTO interventions - Focus on hardware

Dexterous helical magnetic robot for improved endovascular access

Treating vascular diseases in the brain requires access to the affected region inside the body. This is usually accomplished through a minimally invasive technique that involves the use of long, thin devices, such as wires and tubes, that are manually maneuvered by a clinician within the bloodstream. By pushing, pulling, and twisting, these devices are navigated through the tortuous pathways of the blood vessels. The outcome of the procedure heavily relies on the clinician's skill and the device's ability to navigate to the affected target region in the bloodstream, which is often inhibited by tortuous blood vessels. Sharp turns require high flexibility, but this flexibility inhibits translation of proximal insertion to distal tip advancement. We present a highly dexterous, magnetically steered continuum robot that overcomes pushability limitations through rotation. A helical protrusion on the device's surface engages with the vessel wall and translates rotation to forward motion at every point of contact. An articulating magnetic tip allows for active steerability, enabling navigation from the aortic arch to millimeter-sized arteries of the brain. The effectiveness of the magnetic continuum robot has been demonstrated through successful navigation in models of the human vasculature and in blood vessels of a live pig.

Basics of Guidewire Technology and Peripheral Artery Disease

Guidewire technology has advanced significantly over the last several decades. As more components are incorporated providing valuable features, deciding which guidewire to use during peripheral artery disease (PAD) interventions has become more complex. The challenge for both the beginner and expert is not only understanding which components offer the best characteristics in a guidewire but choosing the optimal wire for an intervention. Manufacturers have attempted to optimize components to provide physicians with routinely available guidewires needed in everyday practice. Yet selecting the best guidewire for a particular situation during an intervention is still challenging. This article provides a basic overview of guidewire components and what benefits they offer during PAD interventions.

Use of a Rigid-Tipped Microguidewire for the Endovascular Treatment of Cavernous Sinus Dural Arteriovenous Fistulas with an Occluded Inferior Petrosal Sinus

Objective

Transvenous embolization (TVE) via an occluded inferior petrosal sinus (IPS) in a cavernous sinus dural arteriovenous fistula (CSDAVF) is challenging, often requiring navigation of a microcatheter through resistive obstacles between the occluded IPS and shunted pouch (SP), although the reopening technique was successfully performed. We report five cases of successful access to the cavernous sinus (CS) or SP using the rigid-tipped microguidewire such as chronic total occlusion (CTO) wire aiming to share our initial experience with this wire.

Methods

In this retrospective study, four patients with CSDAVF underwent five procedures using the CTO wire puncture during transfemoral transvenous coil embolization. Puncture success, shunt occlusion, and complications including any hemorrhage and cranial nerve palsy were evaluated.

Results

Despite successful access through the occluded IPS, further entry into the target area using neurointerventional devices was impossible due to a short-segment stricture before the CS (three cases) and a membranous barrier within the CS (two cases). However, puncturing these structures using the rigid-tipped microguidewire was successful in all cases. We could advance the microcatheter over the rigid-tipped microguidewire for the navigation to the SP and achieved complete occlusion of the SP without complications.

Conclusion

The use of the rigid-tipped microguidewire in the TVE via the occluded IPS of the CSDAVF would be feasible and safe.

Turnpike Catheter failure, causes and mechanisms: Insights from the MAUDE database

Background

The Turnpike catheters (Teleflex, Wayne, PA, USA) is a microcatheter that was approved by the Food and Drug Administration in November 2014 to be used to access discrete regions of the coronary and peripheral vasculature.

Methods

The Manufacturer and User Facility Device Experience (MAUDE) database was queried for reports of the Turnpike catheters from March 2015 through August 2021.

Results

A total of 216 reports were found during the study period. After excluding duplicate reports (n = 21), our final cohort included 195 reports. The most common failure mode was catheter tip break or detachment (83%, n = 165) which was significantly associated with over-torquing (p-value = 0.025). The most common clinical consequence was the entrapment of the catheter (33%, n = 65), followed by vessel injury (7.8% n = 15) and vessel occlusion (3.6%, n = 7). Most patients had no consequences (47.0%, n = 93) or recovered (11%, n = 22). A total of 4 deaths were reported. 35.8% of reports (n = 69) specified the presence of severe calcification in the target vessel. Over torquing by interventionists was reported in 33.2% of events (n = 64).

Conclusion

Despite clinical trials demonstrating the safety of the Turnpike catheters, complications can still occur. These data serve to inform operators about potentional risks and complications associated with the use of the device. Physicians should avoid over-torqueing which seems to be the most common mechanism for device complications.

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The Turnpike catheters (Teleflex, Wayne, PA, USA) is a microcatheter that was approved by the Food and Drug Administration in November 2014 to be used to access discrete regions of the coronary and peripheral vasculature.

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Despite clinical trials demonstrating the safety of the Turnpike catheters, complications can still occur. These data serve to inform operators about potential risks and complications associated with the use of the device.

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Physicians should avoid over-torqueing which seems to be the most common mechanism for device complications.

Guiding Principles for the Clinical Use and Selection of Microcatheters in Complex Coronary Interventions

The use of microcatheters as a coronary interventional tool for a therapeutic approach to complex coronary interventions like bifurcation lesions, ostial location, tortuous anatomy, angled takeoffs, coronary calcification, and chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is growing among cardiologists across the country. During the treatment of such complex lesions, microcatheters play an essential part of the tool kit with both single-lumen and double-lumen microcatheters (DLMs) having their specific niche areas. The selection of microcatheters involves a detailed understanding of the microcatheter specification, lesion anatomy, lesion location, vessel tortuosity and trajectory, and crossing techniques. The selection of appropriate crossing techniques with different microcatheters increases success rates of PCI, reduces procedural time and contrast use, and lowers the radiation. However, the use of microcatheters and their technicalities have not yet fully realized by many operators and their true scope has not been fully explored. This article discusses and summarizes the thoughts and key opinions of experts in this field.

The Use of Chronic Total Occlusion (CTO) Wires for Perforation of Atretic Pulmonary Valve; Two Centers Experience

Pulmonary valve atresia with intact ventricular septum (PA-IVS) can be treated either surgically or transcatheterly for eligible patients. Perforation of pulmonary valves using chronic total occlusion (CTO) guidewires has been reported as an alternative to radiofrequency (RF) perforation. We sought to report our experience with CTO guidewires for perforation of atretic pulmonary valves and subsequent balloon dilatation (with or without patent ductus arteriosus stenting) in patients with PA-IVS from two centers. A retrospective study was carried out on PA-IVS patients who underwent intervention between March 2014 and September 2019, in which CTO guidewire was employed for pulmonary valve perforation. A total of 26 patients were identified. The median age and weight of the patients were 5.2 days (range 1-21 days) and 3.1 kg (range 2.2-3.8 kg), respectively. All patients were situs solitus, except one patient with left atrial isomerism. The right ventricle (RV) morphology was bipartite in 22/26 patients and tripartite in 4/26 patients. Before the procedure, the mean saturation was 76% (range 70-86%) while the patients were under prostaglandin infusion. The pulmonary valve perforation attempt was performed with the Asahi Conquest Pro 9 CTO wire (n = 6) or Asahi Pro 12 CTO wire (n = 18) and/or Asahi Miracle CTO wire (n = 2). The procedure was successful in 20/26 (77%) patients using CTO wires. We analyzed the efficiency of CTO wire based on the subtypes: Conquest Pro 9 in 6/6 (100%) patients, Conquest Pro 12 in 12/18 (67%) patients, and Miracle in 2/2 (100%) patients. Before CTO wire usage in 3 patients, radiofrequency (RF) perforation was unsuccessful. Among these 3 patients, pulmonary valve perforation was successful in 2 patients with CTO wire; hence, in the remaining patient, perforation was also unsuccessful with CTO wire. After CTO wire perforation was unsuccessful in 6 patients, RF perforation was attempted in 3 patients (2 successful attempts and 1 unsuccessful attempts), and one patient as referred to surgery. Desaturation was persistent in 19 cases, which necessitated ductus arteriosus stenting. Early procedural complication was observed in 3/26 (11%) patients. Two of these patients had vascular complications due to the sheath, which was treated with heparin infusion and streptokinase, and the remaining patient had sudden bradycardia and cardiac arrest during the procedure and did not respond to cardiac resuscitation. CTO wires should be keep in mind for atretic pulmonary valve perforation as a first choice or when RF perforation is unsuccessful.

Optimal management of pulmonary atresia with intact ventricular septum in a developing country: the art of pulmonary valve mechanical perforation in the era of CTO hardware

BACKGROUND

Transcatheter valve mechanical perforation (TVMP) in pulmonary atresia with intact ventricular septum (PAIVS) is an acceptable yet challenging alternative to radiofrequency.

AIMS

To evaluate and compare safety, feasibility, and efficiency of two TVMP techniques.

METHODS

Clinical data of neonates with PAIVS who underwent an attempt for TVMP between 2009 and 2019 were retrospectively reviewed. Patients were divided into two groups according to perforation technique: using the stiff end of a percutaneous transluminal coronary angioplasty (PTCA) ordinary 0.014" wire (group A) and subsequently with the floppy tip of a chronic total occlusion (CTO) guidewire (group B). The technical aspects, procedural and discharge outcomes of both groups were compared.

RESULTS

A total of 19 antegrade TVMP procedures (Group A, n=10, and Group B, n=9) were attempted in 18 neonates with an overall success rate of 73.7% and no procedure-related mortality. Groups' analysis showed that the introduction of CTO hardware maximized procedure success rates (P=0.002) with zero failure and misperforations (P=0.022). The significant drop in perforation time (P < 0.001) and irradiation exposure (P=0.006) allowed additional ductal stenting during the same procedure, optimizing patients' clinical outcomes and shortening overall hospital stay. Discharged patients had room air mean oxygen saturation of 91.4% (± 5.5) with no evidence of heart failure.

CONCLUSIONS

In selected cases of PAIVS, TVMP using CTO wires is a safer, highly efficient, and simplified alternative to other mechanical perforation techniques. It substantially revolutionized the management of PAIVS in our center optimizing short-term prognosis.

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.

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.

Ostial left main coronary artery chronic total occlusion presenting as chronic stable angina

Significant left main coronary artery (LMCA) disease is found in 5–6% of all patients undergoing coronary angiography. It usually presents as acute coronary syndrome and is commonly associated with multi-vessel coronary artery disease (CAD). Complete occlusion of LMCA is a much rarer finding, since these patients usually present as unstable angina, myocardial infarction and cardiogenic shock. We report a case of a young female, who presented with chronic stable angina and had an isolated chronic total occlusion (CTO) of LMCA with no lesions in the other coronary arteries. Aortogram failed to demonstrate the stump of occluded LMCA and demonstrated the filling of the left coronary system from the right coronary artery. Apart from dyslipidemia, she had no other risk factors for CAD. She was extensively evaluated for non-atherosclerotic causes of LMCA CTO including vasculitis. She underwent coronary artery bypass graft successfully without any peri-procedural complications.

Coronary chronic total occlusion intervention: A pathophysiological perspective

Percutaneous coronary intervention (PCI) of chronic total occlusion (CTO) is the last frontier in coronary intervention. PCI of CTO carries multiple advantages, such as significant improvement in symptoms, improvement in abnormal wall motion and left ventricular function and, possibly, increased long-term survival. As of today the procedural success is markedly improved because of technical innovations and is limited to highly experienced operators. To enhance the overall success rate from a worldwide perspective, a thorough understanding of its pathophysiology is critical to further development of newer techniques and technologies. In this review, the author outlines in-depth the evidence that underpins our understanding of CTO pathophysiology and its insight into CTO intervention that incorporates various steps and techniques to cross the lesion.

Successful Retrieval of Entrapped Gaia Guidewire in Calcified Chronic Total Occlusion Using Rotational Atherectomy Device

We report a novel technique for retrieving an entrapped Gaia guidewires in severely calcified coronary chronic total occlusion (CTO) using a rotational atherectomy device. By successfully cutting the entrapped and untangled guidewire within the CTO with the use of a rotational atherectomy device, we could effectively remove the Gaia guidewire from the right coronary artery.

Utility of adjunctive modalities in Coronary chronic total occlusion intervention

Coronary chronic total occlusion (CTO) intervention remains one of the most challenging domains in interventional cardiology. Due to the technical challenges involved and potential procedural complications, CTO percutaneous coronary intervention (PCI) attempt and success rates remain less than standard PCI. However, the use of several adjunctive tools such as intravascular ultrasound, optical coherence tomography, rotational atherectomy, orbital atherectomy, excimer laser coronary atherectomy and percutaneous left ventricular assist device may contribute to improved CTO PCI success rates or provide better hemodynamic assessment of CTO lesion (i.e., using fractional flow reserve). In this review we present the current literature describing the utility and efficacy of these adjunctive modalities in CTO intervention.

Unraveling the mystique of CTO Interventions: Tips and techniques of using hardware to achieve success

The scientific discourse of chronic total occlusions interventions is mired in a technical jargon so confusing that it prevents an average interventional cardiologist from pursuing this field so much so that it has become a domain of a few. This review attempts to simplify this vernacular and present it in a manner that this procedure comes within the scope of a mainstream interventionist.

Recanalization of Chronic Total Occlusion Lesions: A Critical Appraisal of Current Devices and Techniques

Chronic Total Occlusion (CTO) has been considered as one of the "final frontier" in interventional cardiology. Until recently, the patients with CTO are often managed surgically or medically due to lack of published evidence of clinical benefits and lower success rate of percutaneous recanalization of CTO. However, the introduction of enhanced guidewires, microcatheters combined with novel specialized devices and techniques reduce the number of unapproachable CTO. In this review article, current techniques and devices of percutaneous recanalization of CTO have been systematically summarized, which may help budding interventional cardiologists to theoretically understand these complex procedures and to deliver safe and effective percutaneous management of CTO to the patients.