Crossing chronic total occlusions with the Ocelot system: the initial European experience

Success rate of endovascular recanalization for femoropopliteal artery total occlusion using the wingman catheter system

Chronic total occlusion (CTO) in the femoropopliteal artery is challenging to treat. The Wingman catheter system is a novel device for CTO penetration with a nitinol/stainless steel beveled tip. There is a lack of real-world clinical data indicating the success rate. We evaluated the efficacy of the Wingman system. This was a single-center retrospective study. We enrolled 27 consecutives patients who underwent treatment for femoropopliteal CTO using the Wingman system in 2021. The primary outcome was success of CTO-crossing and secondary outcomes were success of the procedure, Wingman-related complications, and predictors for success of Wingman crossing. The mean age of the study population was 76 years and the mean CTO length was 122 mm. The success rate of Wingman crossing was 40.7% and the overall procedure success rate was 100%. Only one case of embolism and one of perforation associated with the Wingman procedure were seen; both were successfully recovered. Univariate analysis revealed in-stent occlusion and non-severe calcification to be factors associated with success (16.7% vs 0%, p = 0.012 and 12.5% vs 50.0%, p = 0.036, respectively). These real-world data of the Wingman system demonstrate it to be a safe and one of option for treating femoropopliteal CTO.

Optical coherence tomography in peripheral arterial disease: A systematic review

BACKGROUND

Optical coherence tomography (OCT) is a novel adjunct in the field of medicine. The objective of this systematic review was to evaluate the role of OCT in the field of contemporary endovascular surgery in terms of its utility in diagnostics and interventions in peripheral arterial disease (PAD).

METHOD

A systematic search of literature published from 1st January 2009 to 1st August 2019 was identified from PubMed, Ovid and Cochrane library database with reference to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The pre-defined selection inclusion criteria were clinical applications of OCT in vascular surgery in relation to diagnostics and interventions. Keywords used included OCT, PAD, endovascular procedures and atherectomy.

RESULTS

From an initial search of 310 articles, 27 articles were included in this systematic review: 15 articles were related to diagnostics: peripheral arterial disease was the most studied condition (n = 8), other conditions included in-stent restenosis (n = 4), fibromuscular dysplasia (n = 2) and acute limb ischaemia (n = 1); 12 articles were related to intervention: an OCT-guided crossing catheter was the most used assisting device (n = 10), with an OCT-guided atherectomy device used in four of these studies.

CONCLUSION

Although there is currently no level 1 evidence to suggest routine use of OCT in the diagnosis and treatment of PAD, current literature suggests that the use of OCT is safe and effective. The OCT real-time vessel wall structural images clearly distinguish normal anatomy from plaque pathology, and are of great advantage both in the accurate diagnosis and treatment of target lesion, especially in reducing the amount of radiation in the endovascular procedure.

Optical coherence tomography and plaque morphology for revascularization of the superficial femoral artery

Background

The optical coherence tomography (OCT) catheter, Ocelot (Avinger Inc., Redwood City, CA), has been utilized to cross Trans-Atlantic Inter-Society Consensus Document (TASC) D lesions. Studies have assessed the characteristics of high-risk plaques in the carotid artery, but few, if any data exist evaluating OCT and plaque morphology in the superficial femoral artery (SFA). This study assessed SFA plaque morphology using OCT and lesion crossing success in chronic total occlusions (CTOs).

Methods

We reviewed patients who underwent attempted infrainguinal revascularization with TASC D CTOs using the Ocelot catheter between June 2014 and June 2018, and recorded demographic information, smoking status, and medical comorbidities. A matched cohort of 44 successfully crossed lesions was compared to 44 that failed; images insufficient for analysis were excluded. The morphology of the plaque was studied using OCT at the proximal cap, midpoint of the lesion, and the distal cap. Morphologic data studied included the intima-media thickness ratio, cross-sectional area of the plaque, and gray-scale median of the plaque.

Results

A total of 140 patients who underwent lower extremity procedures for TASC D lesions of the SFA with OCT imaging were reviewed with a crossing rate of 69.0%. No significant differences were found between crossed and uncrossed lesions for intima-media thickness or cross-sectional area at the proximal cap, the midpoint, or the distal cap. A lower gray-scale median at the proximal cap was associated with the ability to cross the chronic SFA occlusion (P=0.05). Subgroup analysis stratified by smoking and calcium content also demonstrated that a lower gray-scale median at the proximal cap was associated with the ability to cross the chronic SFA occlusion (P=0.01 and P=0.04, respectively).

Conclusions

Lower gray-scale median at the proximal cap of a chronic SFA occlusion calculated using OCT images was associated with the ability to successfully cross the lesion. Higher plaque gray-scale median is correlated with increased calcium, greater fibrous tissue, and signal-rich plaques. Gray-scale median in the proximal cap is useful marker to determine plaque composition and subsequent technical success for crossing chronic SFA occlusions. Further studies are needed to fully determine the utility of OCT images to predict successful endovascular revascularization of chronic SFA occlusions.

Use of the Ocelot catheter in iliac chronic total occlusion intervention

PURPOSE

The optical-coherence tomography guided Ocelot catheter has previously been shown to be a safe and effective tool for crossing peripheral chronic total occlusions. However, the existing literature focuses mostly on the superficial femoral artery, without prior evidence of use within the suprainguinal vasculature.

CASE SERIES

We present the first known cases of the Ocelot catheter for revascularization of chronic total occlusions in the iliac vasculature. In the first case a retrograde approach is used for intervention of the right common iliac artery, while in the second case an antegrade approach is used for revascularization of the left external iliac artery.

CONCLUSIONS

In this case report we first demonstrate as proof of feasibility the use of the Ocelot catheter in suprainguinal artery chronic total occlusions.

Preoperative assessment of computerized tomography angiography to predict success for crossing long Trans-Atlantic Inter-Society Consensus D lesions using the optical coherence tomography catheter

Objectives Optical coherence tomography chronic total occlusion catheter, the Ocelot (Avinger Inc., Redwood City, CA), has been utilized to cross Trans-Atlantic Inter-Society Consensus D lesions. This study evaluated the preoperative computerized tomography angiography of chronic total occlusions in the superficial femoral artery to predict clinical success. Methods We reviewed all patients who underwent lower extremity procedures with the Ocelot catheter from June 2014 to August 2016. Patients who had a preoperative computerized tomography angiography were evaluated. Final outcomes, plaque morphology, lesion length, calcium surface area, lesion location, and patient characteristics were analyzed. Results A total of 107 patients underwent lower extremity interventions with the Ocelot catheter. Seventy patients had a preoperative computerized tomography angiography scan prior to lower extremity intervention and 77% (54) had Trans-Atlantic Inter-Society Consensus D lesions that were crossed. Mean age was 62.8 years and 68.6% were male. Mean chronic total occlusion length was 182.7 mm (170.8 mm crossed vs. 222.6 mm uncrossed, p = 0.03). Calcium distribution differed significantly ( p<.01): circumferential (14.8 vs. 12.5%); eccentric (85 vs. 62.5%); and complete calcium occlusion (0 vs. 25%) for lesions that were crossed and uncrossed, respectively. Significant differences ( p<.0001) were found when calcium occlusion was less than 50% (87 vs. 31%), 51-75% (9.3 vs. 31.2%), and 76-100% (3.7 vs. 37.5%). Total calcium length in crossed lesion was 51.6 mm, and 92.8 mm in uncrossed lesions ( p = 0.10). No significant differences were noted for patient gender, occlusion location (proximal, middle, and distal superficial femoral artery), and kidney function. Conclusion The Ocelot catheter is an effective method to cross long Trans-Atlantic Inter-Society Consensus D lesions. Superficial femoral artery lesions longer than 17 cm and focal plaque morphology, specifically a total cross-sectional area of calcium and a calcium surface area greater than 50% were most predictive of failure to cross Trans-Atlantic Inter-Society Consensus D superficial femoral artery lesions. Computerized tomography angiography is an effective tool to predict success for crossing chronic total occlusions using optical coherence tomography technology and a critical consideration for patient selection.

Outcome After Crossing Femoropopliteal Chronic Total Occlusions Based on Optical Coherence Tomography Guidance

AIMS

The crossing of chronic total occlusions (CTOs) is the key step for an endovascular treatment. The Ocelot system is a novel device that combines a steerable drilling tip with optical coherence tomography (OCT) technology. It provides intraluminal imaging to help the crossing of CTOs in the femoropopliteal segment. Aim of the study was to determine early and midterm results after recanalization with this device.

METHODS AND RESULTS

During a period of 16 months, 84 CTOs were treated using the Ocelot system and prospectively registered. The primary end points were technical success and the primary and secondary patency of the lesion. Risk factors associated with early and midterm results were also analyzed. In all, 58 (69.0%) lesions were treated for intermittent claudication, 26 (31.0%) for critical limb ischemia, 34 (40.5%) were classified as Trans-Atlantic Inter-Society Consensus II D lesions, and 22 (26.2%) showed severe calcifications. The technical success rate was 72.6%. During 36 months of follow-up (mean 25.9), there were 10 reinterventions. The primary and secondary patency at 36 months were 54.2% and 68.1%, respectively.

CONCLUSIONS

In our experience, the Ocelot system would appear to be a safe and effective tool for increasing the applicability of endovascular techniques. However, the midterm results did not show drastic improvement.

Utility of Intravascular Ultrasound in Percutaneous Revascularization of Chronic Total Occlusions: An Overview

Intravascular ultrasound has been used for >20 years to guide percutaneous coronary intervention in different subsets of coronary lesions. During the last decade, the interest in percutaneous coronary intervention for chronic total occlusion (CTO) has increased dramatically, leading to high success rates. Failure of guidewire crossing is the most common reason for failed CTO attempts. Certain angiographic features, such as blunt proximal CTO cap, tortuosity, heavy calcification, and lack of visibility of path in the distal vessel, increase procedural difficulty. A better understanding of the behavior of the guidewire within the CTO segment may represent a key issue to achieve successful outcome. In this respect, intravascular ultrasound imaging might have potential roles in the recanalization of CTOs. In this paper, we focused on the usefulness and the applications of intravascular ultrasound imaging in percutaneous CTO recanalization, underlying its impact on clinical outcome.

Crossing Total Occlusions: Navigating Towards Recanalization

Chronic total occlusions (CTOs) represent the "last frontier" of percutaneous interventions. The main technical challenges lies in crossing the guidewire into the distal true lumen, which is primarily due to three problems: device buckling during initial puncture, inadequate visualization, and the inability to actively navigate through the CTO. To improve the success rate and to identify future research pathways, this study systematically reviews the state-of-the-art of all existing and invented devices for crossing occlusions. The literature search was executed in the databases of Scopus and Espacenet using medical and instrument-related keyword combinations. The search yielded over 840 patents and 69 articles. After scanning for relevancy, 45 patents and 16 articles were included. The identified crossing devices were subdivided based on the determinant for the crossing path through the occlusion, which is either the device (straight and angled crossing), the environment (least resistance, tissue selective, centerline, and subintimal crossing) or the user (directly steered and sensor enhanced crossing). It was found that each crossing path is characterized by specific advantages and disadvantages. For a future crossing device, a combination of crossing paths is suggested were the interventionist is able to exert high forces on the CTO (as seen in the device approach) and actively steer through the CTO (user: directly steered crossing) aided by intravascular imaging (user: sensor enhanced crossing) or an intrinsically safe device following the centerline or path of least resistance (environment: centerline crossing or least resistance crossing) to reach the distal true lumen.

Endovascular intervention for peripheral artery disease

Advances in endovascular therapies during the past decade have broadened the options for treating peripheral vascular disease percutaneously. Endovascular treatment offers a lower risk alternative to open surgery in many patients with multiple comorbidities. Noninvasive physiological tests and arterial imaging precede an endovascular intervention and help localize the disease and plan the procedure. The timing and need for revascularization are broadly related to the 3 main clinical presentations of claudication, critical limb ischemia, and acute limb ischemia. Many patients with claudication can be treated by exercise and medical therapy. Endovascular procedures are considered when these fail to improve quality of life and function. In contrast, critical limb ischemia and acute limb ischemia threaten the limb and require more urgent revascularization. In general, endovascular treatments have greater long-term durability for aortoiliac disease than femoral popliteal disease. Infrapopliteal revascularization is generally reserved for critical and acute limb ischemia. Balloon angioplasty and stenting are the mainstays of endovascular therapy. New well-tested innovations include drug-eluting stents and drug-coated balloons. Adjunctive devices for crossing chronic total occlusions or debulking plaque with atherectomy are less rigorously studied and have niche roles. Patients receiving endovascular procedures need a structured surveillance plan for follow-up care. This includes intensive treatment of cardiovascular risk factors to prevent myocardial infarction and stroke, which are the main causes of death. Limb surveillance aims to identify restenosis and new disease beyond the intervened segments, both of which may jeopardize patency and lead to recurrent symptoms, functional impairment, or a threatened limb.