Alternative Combined Retrograde–Antegrade Use of a Re-entry Device in the Revascularization of a Surgically Ligated Superficial Femoral Artery Occlusion

We report a case of a diabetic patient with critical limb ischemia, who previously underwent thromboendarterectomy at the right lower extremity, resulting in surgical ligation at the proximal third of the right superficial femoral artery (SFA). Twenty months later, the patient developed foot ulcers; endovascular treatment was therefore performed. After obtaining a retrograde right SFA subintimal access, directly puncturing the occluded segment of the artery, a re-entry intravascular ultrasound-guided catheter was used to gain proximal re-entry. Then, the same device was used again, in antegrade fashion, to obtain re-entry into the patent popliteal artery. A covered stent was deployed in the site of the surgical closure. In the following 3 months, foot ulcers healed.

Revascularization of Coronary Artery Chronic Total Occlusion by Active Antegrade Reverse Wire Technique

Objectives. To assess the effectiveness and safety of ARW for vascular recanalization in CTO patients. Background. Chronic total occlusion (CTO) of coronary artery accompanied with large branch distal to the occluded segment (<2 mm) is one of the challenges physicians are facing during the coronary intervention. In cases where the antegrade wire passed the occluded segment reaching the branch vessel, but could not access the main vessel through various adjustments, application of active antegrade reverse wire technique (ARW) could be considered. Patients and Methods. A total of 301 consecutive CTO patients who received the antegrade percutaneous coronary intervention (PCI) between December 2015 and December 2019 at our institution were included, of whom 11 were treated with ARW (10 successfully) for vascular recanalization. The applicability and safety of ARW were assessed. Results. Among the 301 CTO patients who received antegrade vascular recanalization, 11 were treated with ARW. ARW was successful in 10 patients as follows: from the diagonal branch (D) to anterior descending branch (LAD) in 4 patients; from the septal branch (S) to LAD in 1 patient; from D to S and LAD in 1 patient; from the circumflex branch (LCX) to obtuse marginal branch (OM) in 1 patient; from OM to LCX in 1 patient; from a posterior descending artery (PDA) to the posterior lateral vein (PLV) in 2 patients. Yet, ARW in patient with RCAm CTO failed, while the consequent retrograde PCI succeeded. The mean J-CTO score of the 11 patients was 2.7 ± 0.65, among whom eight were accompanied with calcifications. Sion Black and Fielder XTR reverse wires were used in 9 and 2 patients, respectively. No loss of side branches or severe procedure-related complications occurred in 11 patients. Conclusion. Therefore, ARW can improve procedural efficiency and should be popularized for further application.

Experimental investigation of the combined system for mechanical thrombectomy

<p><strong>Background.</strong> The intravenous administration of tissue plasmongen activator within 4.5 h of the onset of acute ischaemic stroke is known to improve the treatment outcomes significantly. However, in 2015, five large studies simultaneously demonstrated the superiority of a mechanical revascularisation strategy over a drug-based approach. As a results of these studies, the updated guidelines, providing an advantage of mechanical thromboextraction.</p><p><strong>Aim.</strong> To evaluate the effectiveness of the combined system for mechanical thrombus extraction.</p><p><strong>Methods.</strong> We prepared a prototype of a combined system for mechanical thrombextraction in ischaemic stroke. We performed a trial on a laboratory animal in order to assess the efficiency of the system.</p><p><strong>Results.</strong> Our results show that mechanical thrombus extraction using the domestic prototype of the combined thrombextraction system was highly efficient. Complete restoration of blood flow was observed in the previously occluded segment.</p><p><strong>Conclusion.</strong> Our study demonstrated prototype of a combined system for mechanical thrombus extraction effectiveness in preclinical study.</p><p>Received 10 December 2020. Revised 16 December 2020. Accepted 21 December 2020.</p><p><strong>Funding:</strong> The work is supported by a grant (project No. 056-00042-20-00).</p><p><strong>Conflict of interest:</strong> Authors declare no conflict of interest.</p>

A Novel, Modified Reverse Controlled Antegrade and Retrograde Subintimal Tracking Technique for Bypassing the Calcified Proximal Cap of Coronary Total Occlusions

Antegrade crossing is the most common approach to chronic total occlusions (CTOs). However, it is sometimes difficult to penetrate the proximal hard cap with guidewires, especially in the case of CTOs of anomalous coronary arteries because of a lack of support. Herein, we describe a novel, modified reverse controlled antegrade and retrograde subintimal tracking (CART) technique in which the dissection reentry was intentionally created in the proximal segment of the vessel, not within the occluded segment, using retrograde guidewire and the aid of an antegrade balloon. This technique facilitated retrograde crossing of CTOs by avoiding the proximal hard cap and may provide a viable option for patients in which conventional reverse CART is not possible.

Abstract 19665: Angiographic Predictors of Successful Guide-wire Crossing Through Infrapopliteal Chronic Total Occlusions (CTOs)

Background: No current scoring system exists to predict successful guide-wire crossing of infrapopliteal CTOs. Methods: All patients undergoing peripheral endovascular procedures from 2006 to 2014 at University of California, Davis and Denver Veterans Affairs Medical Centers were reviewed. Interventions performed on anterior tibial, peroneal, or posterior tibial artery CTOs were identified. Angiographic analysis was performed to identify stump morphology, presence of bridging collaterals and side branches near the stump, calcification at entry and within the occluded segment, and the length and the diameter of the lesion. Angiographic predictors of successful wire crossing were then identified. Results: 215 cases of infrapopliteal CTOs were performed at the two centers during the study period. Antegrade wire crossing was successful in 151 cases (70%). Failure of antegrade wire crossing was associated with a beaded stump morphology (15% of failure cases vs. 4% of successful cases, p<0.01); presence of severe calcification at the entry point (56% of failure cases vs. 34% of successful cases, p = 0.02); presence of severe calcification in the occluded route (52% of failure cases vs. 33% of successful cases, p = 0.04); an occluded segment longer than 200 mm (51% of failure cases vs. 17% of successful cases, p<0.01); and reference vessel diameter smaller than 2.5 mm (63% of failure cases vs. 37% of successful cases, p<0.01). The presence of bridging collaterals and side branches were not significantly associated with success or failure of antegrade wire crossing (Table). Conclusions: A beaded stump morphology at the proximal cap, presence of severe calcification at the entry site and in the occluded route, longer occluded segment length, and narrower reference vessel diameter are associated with greater failure of antegrade wire crossing for infrapopliteal CTOs. A scoring system will be developed to identify multivariable predictors of antegrade wire crossing.

Corrective spinal surgery may be protective against stroke in patients with blunt traumatic vertebral artery occlusion

OBJECT Approximately 10% of patients with blunt traumatic extracranial cerebrovascular injury have a complete occlusion of the vertebral artery (VA). Ischemic stroke due to embolization of thrombus from an occluded VA following cervical spine surgery has been observed. The risk of ischemic stroke with cervical spine surgery in the presence of an occluded VA, however, has never been determined. METHODS A retrospective chart review of 52 patients with a VA occlusion following a blunt trauma was performed. Clinical and radiographic characteristics were collected and analyzed. RESULTS Ten patients (19.2%) suffered an ischemic stroke attributable to a traumatic VA occlusion. Univariate analysis demonstrated that patients with ischemic stroke were significantly older (p = 0.042) and had a lower rate of cervical spine surgery (p < 0.005). Multivariate analysis found cervical spine surgery to be protective against ischemic stroke (OR 0.049 [95% CI 0.014–0.167], p = 0.014); increasing age and bilateral VA injury (bilateral occlusion or unilateral occlusion with contralateral dissection) were risk factors for ischemic stroke (OR 1.05 [95% CI1.02–1.07], p = 0.065 and OR 13.2 [95% CI 2.98–58.9], p = 0.084, respectively). CONCLUSIONS Traumatic VA occlusion is associated with a risk of ischemic stroke and mortality. Corrective cervical spine surgery potentially decreases the risk of ischemic stroke by stabilizing the spine and thereby reducing motion across the occluded segment of the VA and preventing embolization of thrombus. While a high stoke risk may be inherent to the disease, novel therapies should be investigated.

The Unique Disulfide Bond-stabilized W1 β4-β1 Loop in the α4 β-Propeller Domain Regulates Integrin α4β7 Affinity and Signaling

Integrin α4β7 mediates rolling and firm adhesion of lymphocytes pre- and post-activation, which is distinct from most integrins only mediating firm cell adhesion upon activation. This two-phase cell adhesion suggests a unique molecular basis for the dynamic interaction of α4β7 with its ligand, mucosal addressin cell adhesion molecule 1 (MAdCAM-1). Here we report that a disulfide bond-stabilized W1 β4-β1 loop in α4 β-propeller domain plays critical roles in regulating integrin α4β7 affinity and signaling. Either breaking the disulfide bond or deleting the disulfide bond-occluded segment in the W1 β4-β1 loop inhibited rolling cell adhesion supported by the low-affinity interaction between MAdCAM-1 and inactive α4β7 but negligibly affected firm cell adhesion supported by the high-affinity interaction between MAdCAM-1 and Mn2+-activated α4β7. Additionally, disrupting the disulfide bond or deleting the disulfide bond-occluded segment not only blocked the conformational change and activation of α4β7 triggered by talin or phorbol-12-myristate-13-acetate via inside-out signaling but also disrupted integrin-mediated outside-in signaling and impaired phosphorylation of focal adhesion kinase and paxillin. Thus, these findings reveal a particular molecular basis for α4β7-mediated rolling cell adhesion and a novel regulatory element of integrin affinity and signaling.

Passing the Thrombus in Endovascular Treatment of Acute Ischemic Stroke: Do We Penetrate the Thrombus?

Mechanical thrombectomy is increasingly applied during the treatment of acute stroke. Various devices have been advocated with different sites of force effect at the thrombus. The purpose of this study was to evaluate the angiographic route of passing systematically and therefore to assess the site of deployment of mechanical devices in correlation to the thrombus in interventional stroke treatment. Twenty-one consecutive patients with endovascular treatment for acute ischemic stroke with 26 passing procedures were evaluated prospectively. Occlusion site was the M1-segment in 17 cases (65.4%), ICA termination in five cases (19.2%), M2-segment in two cases (7.7%), the A2-segment in one case (3.8%) and basilar artery in one case (3.8%). On angiographic images the microwire and microcatheter passage was evaluated by illustrating the entry point and course across the occlusion site in relation to the thrombus in different projections and in correlation to the recanalisation result. Results were correlated to the origin of the thrombi according to the TOAST criteria. In all cases the point of entry to the occlusion site was delineated laterally to the thrombus in at least one projection. The course of the wire across the occluded segment in relation to the thrombus was found to be laterally in 22 procedures (84.6%). In the majority of M1-occlusions (12/17, 70.6%) the passage was found in the cranial aspect of the thrombus. In four procedures (15.4%) angiograms in different projections did not unequivocally confirm a passage laterally to the thrombus. The route of passing the thrombus was independent of thrombus origin according to the TOAST criteria. In the majority of cases the complete route of passing the occlusion site was visualized angiographically. Entrance of the microwire and microcatheter at proximal surface of the thrombus takes place laterally to the thrombus and accordingly the passage takes place between the thrombus and the vessel wall independent of thrombus origin. A penetration of the thrombus was not observed. This route of passing has implications on deployment and transmission of force in relation to the thrombus in mechanical approaches and consequently on the development of retrieval devices.

What is the Real Risk of Dislodging Thrombi During Endovascular Revascularization of a Proximal Internal Carotid Artery Occlusion?

BACKGROUND: There is a theoretical concern that a thrombus may be dislodged distally when crossing the occluded segment during recanalization of a complete occlusion. OBJECTIVE: To assess the immediate postprocedural brain diffusion-weighted image (DWI) findings following endovascular recanalization using an embolic protection device for proximal internal carotid artery (ICA) occlusion. MATERIALS AND METHODS: We retrospectively identified 12 patients who underwent stent implantation for sudden symptomatic occlusion of the proximal ICA. In 8 patients, no additional intracranial occlusions were identified. In 4 patients, an additional intracerebral thrombus was detected in the middle cerebral artery. Distal protection devices were used in all cases. We evaluated the presence and amount of retrieved embolic fragments in the distal protection devices. The incidence and location of postprocedural emboli were determined using DWI. RESULTS: Recanalization of the proximal ICA was achieved in all patients. After complete occlusion of the proximal ICA was demonstrated, primary passage of the embolic protection device through the occluded ICA was gently navigated in 7 patients. However, this was not possible in 5 patients. Three patients developed new lesions on postprocedural DWI. Of the 12 patients in which distal protection devices were used, debris was detected in 7 patients. CONCLUSION: In endovascular revascularization of proximal ICA occlusion, postprocedural emboli occur less frequently than reported in a systematic review of the DWI literature. The real risk of dislodging thrombi appears to be from plaque fragment mobilization by angioplasty, rather than from crossing an occluded segment.

Landmark-Wire Technique of Symptomatic Subclavian Artery Occlusion

The landmark at the opposite end of an occluded segment can be used for probing the occluded subclavian artery to be recanalized. Using this technique in three patients with symptomatic subclavian artery occlusion, we found the landmark-wire technique to be safe and effective for reopening completely occluded subclavian arteries. We also introduced a technique in which a protective device can be safely used throughout the stenting procedure.