Guidewire crossing techniques in coronary chronic total occlusion intervention: A to Z

The CathCam: A Novel Angioscopic Solution for Endovascular Interventions

Peripheral arterial diseases are commonly managed with endovascular procedures, which often face limitations in device control and visualization under X-ray fluoroscopy guidance. In response, we developed the CathCam, an angioscope integrated into an expandable cable-driven parallel mechanism to enhance real-time visualization, precise device positioning and catheter support for successful plaque crossing. The primary objective of this study was to assess and compare the performance of the novel CathCam with respect to conventional catheters and the CathPilot (i.e., CathCam without the angioscope), for applications in crossing chronic total occlusions (CTO). We first assessed the system in 3D-printed phantom models, followed by an ex vivo evaluation with CTO samples from a patient's superficial femoral artery. We measured and compared success rates, crossing times, and fluoroscopy times in both experiments. The CathCam demonstrated a 100% success rate in phantom experiments and a 75% success rate in ex vivo experiments with CTO samples, compared to conventional catheters, with 35% and 25% success rates, respectively. The average crossing times for the CathCam and the conventional catheter were 31 s and 502 s for the phantom experiments and 210 s and 511 s for the actual CTO lesions. The Cathcam also showed to be a reliable endovascular imaging approach in an in vivo experiment. Compared to conventional catheters, the CathCam significantly increased the success rate and reduced crossing and fluoroscopy times in both phantom and ex vivo setups. CathCam can potentially improve clinical outcomes for minimally invasive endovascular interventions by offering high-resolution real-time imaging alongside accurate device control.

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.

STEMI with flush occlusion of a coronary artery: An interventional dilemma

Flush occlusions of coronary arteries present with multiple challenges during primary percutaneous coronary intervention (PPCI). We describe a case of anterior ST-elevation myocardial infarction in cardiogenic shock, where it was not possible to identify the origin of left anterior descending artery (LAD) as it was flush occluded and initial attempts to place a coronary guidewire in the LAD during PPCI were unsuccessful. After failed attempts with multiple guidewires, a combined pharmacological-mechanical approach resulted in successful timely revascularization and subsequent recovery of the patient. <Learning objective: Acute flush occlusion of a major coronary artery is a challenge to interventionists as there may not be any clue of occluded coronary artery. In this difficult scenario, when the wire placement is not possible, the intracoronary infusion of a thrombolytic agent helps in visualization of stump of an occluded artery, facilitating its quick wiring and procedure.>.

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.

Knuckle wire technique in percutaneous coronary intervention of chronic total occlusion: Knuckle wire technique

In percutaneous coronary intervention, the knuckle wire technique is one of the approaches to cross the long and ambiguous course of the occluded segment. However, this technique is generally used as a last alternative, when all other techniques fail. Although knuckle wiring expedites chronic total occlusion crossing, it can also complicate the percutaneous coronary intervention strategy irreversibly. Therefore, understanding the various aspects of the knuckle wire technique is a prerequisite in a chronic total occlusion setting. The authors herein intend to describe in detail the knuckle wire technique and its safe and effective approach in various chronic total occlusion wiring strategies, while befitting to the scope of a mainstream interventionist.

Iteration of Reverse Controlled Antegrade and Retrograde Tracking for Coronary Chronic Total Occlusion Intervention: a Current Appraisal

Coronary chronic total occlusion (CTO) remains one of the most challenging subsets for percutaneous coronary intervention (PCI). The retrograde recanalization is one of the most significant amendments of the technique that remains critical to improved success of CTO PCI. Currently the reverse controlled antegrade and retrograde tracking (CART) is the most dominant retrograde technique. With emergence of new equipment and important iterations, this approach has become safer, faster and more successful. In this review, the author proposes the iteration and standardization of this technique which would further facilitates its adoption with more efficacy and safety.

Native Microchannel Recanalization with Orbital Atherectomy as a Viable Alternative to Failed Standard Recanalization of TASC II D Aortoiliac Occlusive Disease

BACKGROUND

Endovascular treatment of Trans-Atlantic Inter-Society Consensus (TASC) II D aortoiliac lesions is now an accepted form of revascularization. We sought to demonstrate that native microchannel recanalization and orbital atherectomy is a successful recanalization method of TASC II D aortoiliac lesions refractory to standard recanalization techniques.

METHODS

Four consecutive patients from 2016 to 2018 with symptomatic TASC II D aortoiliac occlusive disease prohibitive for open bypass and failed traditional prodding guidewire or device recanalization technique were identified and underwent advanced native microchannel selection and subsequent orbital atherectomy (Cardiovascular Systems, Inc, St Paul, MN). Native microchannels of the calcified lesions were probed and traversed with a 0.014″ wire. The atherectomy crown was tracked over the wire, and orbital atherectomy was initiated with a 1.25 mm crown starting at the lowest revolution and continued until the microchannel is sufficiently large to track a 1.2 mm-balloon for angioplasty. Serial microchannel angioplasty with exchange for stiffer and/or larger profile wires and balloons was achieved until a covered stent could be safely deployed across the target lesion. The kissing stent technique was then used to recreate the aortic bifurcation. A ViperSlide lubricant solution was used in all cases per indication for use. Patients were all heparinized to maintain an activated clotting time of 250. Lesion characteristics, survival, limb salvage, patency, and change in clinical symptoms were also analyzed.

RESULTS

All 4 patients underwent successful native microchannel recanalization and orbital atherectomy of the common iliac artery (CIA). There were no intraoperative ruptures, embolizations, or dissections. All 4 patients presented with unilateral CIA occlusion with contralateral CIA stenosis. The average occlusion lesion length of the CIA was 6.0 cm. The average contralateral stenosis length was 2.3 cm. The kissing stent technique was used in all patients for reconstruction of the aortic bifurcation. At 30 days, all patients had improvement in pain and primary patency of 100%. Long-term follow-up at 21.6 months noted continued improvement in symptoms and primary patency of 75%. The fourth patient died at 4 months from lung cancer with occluded iliac stents by imaging at that time.

CONCLUSIONS

Native microchannel recanalization with subsequent orbital atherectomy is an option in high-risk patients with TASC II D aortoiliac disease who have failed traditional recanalization techniques. Further work in proper patient selection and safe utilization of atherectomy devices in the CIA is needed.

Nitinol actuated soft structures towards transnasal drug delivery: a pilot cadaver study

Sudden hearing loss can be treated noninvasively by administering drugs to the middle ear (≈1 ml) via the eustachian tube. The nasopharyngeal cavity requires high dexterity manipulation as it is restricted by the nasal vestibule, and precise drug delivery through the small cavity can allow previously unreachable areas to be reconsidered for localized delivery. Nitinol has shape memory capabilities and can be used for distal actuation accessed from small lumen and a tortuous path. The drug delivery device (DDD) is a soft and needle-sized (2 mm) and comprises of Nitinol, ribbon spring, and a drug delivery tube. By controlling the input voltage to the Nitinol, bending of the device at different angles could be achieved, and the ribbon spring works antagonistically to the Nitinol to revert to the initial position once deactivated. The actuation of the device and its corresponding bending are calculated in vitro and found to have a bending angle ranging between 36.2 and 66.8° for applied voltages of 1.2-2.0 V, with surface temperature of 45.6-154 °C. The DDD is able to actuate 200 cycles with ≈91-76% retention of bending performance, with a temperature increase of ≈8.5-9% when 1.2-2.0 V is applied. Addition of soft insulating material shows ≈34-62% reduction in the surface temperature in the first cycle and ≈37-59% over 200 cycles when actuated at 1.2-2.0 V. The active steering and navigation capabilities of the DDD are demonstrated in simulated environments (based on the eustachian tube dimensions of adult and infant). Preclinical testing in human cadavers is demonstrated and suggests the developed DDD controlled by varying the input voltages for bending, and mechanically varied drug delivery may be a feasible option for localized drug delivery in eustachian tube. Graphical abstract.

Procedural and follow-up clinical outcomes after chronic total occlusion revascularization: Data from an Indian public hospital

BACKGROUND

Chronic total occlusion (CTO) continues to be challenging lesion subset for percutaneous intervention. Last decade has seen tremendous increase in percutaneous coronary intervention (PCI) in this subset owing to improved understanding of the anatomy and enhanced skillset with availability of dedicated hardware. We sought to study the outcomes of CTO PCI in an Indian public hospital.

METHODS

This was a single-center non-randomized descriptive follow-up study on CTO PCI. The end-points were procedural success, immediate, and late adverse cardiovascular events [major adverse cardiac event (MACE)] and change in angina and left ventricular function at follow-up.

RESULTS

A total 389 CTO lesions were treated with a success rate of 87% (339/389). The mean Japanese chronic total occlusion (J-CTO) score was 1.78 ± 0.12 (mean ± standard deviation). Multivariate analysis of different angiographic components of J-CTO score identified tortuosity (p = 0.001), calcifications (p ≤ 0.001), and blunt stump (p = 0.007) as independent predictors of procedural failure. The periprocedural mortality was less than 1%, and the non-life threatening complications were about 4%. The MACE rate was significantly higher in the procedural failure group (60%) than in the procedural success group (5.3%, p < 0.001). An increase in left ventricular ejection fraction (LVEF) was noted following successful CTO PCI after complete revascularization.

CONCLUSIONS

The success rates for CTO PCI in this registry were about 87%. Immediate and long-term clinical outcomes were better with lower MACE (5%) after a successful procedure. A key outcome variable included an increase in LVEF among patients after a successful CTO PCI. The overall periprocedural complications were about 5.5%, but majority were non-life threatening.

A step-by-step guide to mastering retrograde coronary chronic total occlusion intervention in 2018: The author's perspective

Chronic total occlusion remains one of the most challenging subsets and represents the "last frontier" of percutaneous coronary intervention. Retrograde recanalization is one of the most significant amendments of the technique and has become an important complement to the classical antegrade approach. It yields a high success rate even in most complex patients. With emergence of important iterations, this approach has become safer, faster, and more successful. The author proposes a step-by-step guide to the retrograde approach with alternatives to various steps for operators wishing to embark on this strategy.

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.

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.

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.

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.

Language of CTO interventions - Focus on hardware

The knowledge of variety of chronic total occlusion (CTO) hardware and the ability to use them represents the key to success of any CTO interventions. However, the multiplicity of CTO hardware and their physical character and the terminology used by experts create confusion in the mind of an average interventional cardiologist, particularly a beginner in this field. This knowledge is available but is scattered. We aim to classify and compare the currently used devices based on their properties focusing on how physical character of each device can be utilized in a specific situation, thus clarifying and simplifying the technical discourse.