Comparison of the safety and efficacy of Neuroform Atlas stent deployed via Gateway balloon catheter and microcatheter for the treatment of intracranial stenosis

OBJECTIVE

This study aimed to compare the safety and efficacy of the Atlas stent released by the Gateway catheter and microcatheter in the treatment of intracranial stenosis (IS).

METHODS

The primary efficacy and safety outcomes were the in-stent restenosis (ISR) rate and post-procedural stroke or death within one month.

RESULTS

Atlas stents were deployed using the Gateway catheter and microcatheter in 19 (57.6 %) and 14 (42.4 %) procedures, respectively. Follow-up imaging data were available for 26 patients; the incidence of ISR was 15.4 %, and the ISR rate was higher, though not significantly, in the microcatheter group than in the Gateway group (30.0% vs. 6.25 %, P = .39). Clinical follow-up data were available for 30 patients; the post-procedural stroke rate was 3.3 % within one month and 13.3 % from one month to one year. The post-procedural stroke rate within one month was higher, though not significantly, in the microcatheter group than in the Gateway group (7.7% vs. 0 %, P = .43). The Gateway group had a significantly lower rate of post-procedural stroke in the same territory than that of the microcatheter group (0% vs. 30.8 %, P = .026). A higher incidence of residual stenosis <30 % was found in the non-ISR group than in the ISR group (72.2% vs. 0 %, P = .014).

CONCLUSIONS

This study provides preliminary evidence that the Atlas stent is safe and effective for IS treatment. The use of the Gateway catheter to deliver the Atlas stent appears to be safer than using microcatheter. The incidence of ISR may be related to the degree of the residual stenosis.

Three-Dimensional (3D) Microcatheter Shaping Using Touch Screen Devices for Cerebral Aneurysm Coil Embolization

OBJECTIVE

In cerebral aneurysm coil embolization, proper microcatheter shaping is crucial to reduce complications and achieve sufficient embolization. Shaping a microcatheter in 3 dimensions (3D) is often required but can be challenging. We assessed the usefulness of a novel shaping on screen (SOS) method that displays real-size 3D rotational angiography (RA) images on a touch screen device during cerebral aneurysm embolization to facilitate 3D microcatheter shaping.

METHODS

In this study, 18 patients with cerebral aneurysm treated with this technique were included. Real-size 3D-RA images obtained during the embolization procedure were displayed on the touch screen device, which allowed for real-time manipulation. The shape of the microcatheter was adjusted to conform to the curvature of the vessel by swiping the touch screen device and bending the mandrel accordingly. We assessed the clinical and angiographic results, along with the accuracy and stability of the microcatheter.

RESULTS

No procedure-related complications were observed. The mean packing density was 41% ± 12%. In all but 1 case, microcatheters were inserted into the aneurysms without guidewire assistance. After coiling, all microcatheter forms were stable.

CONCLUSIONS

Three-dimensional (3D) microcatheter shaping using touch screen devices during cerebral aneurysm coil embolization may be simple and safe and can achieve high packing density of aneurysms.

"The microcatheter contrast injection technique": A novel technique to detect the proximal end of a thrombus in mechanical thrombectomy

Background: An aspiration catheter needs to attach to a thrombus in order to achieve first-pass recanalization by mechanical thrombectomy (MT) for acute ischemic stroke (AIS), particularly that using a direct aspiration first pass technique. The meniscus sign, which is defined as meniscoid contrast opacification indicating the proximal edge of a thrombus, has been suggested to contribute to successful recanalization. In some cases, the meniscus sign is not detected following an injection of contrast medium through a guiding catheter. To precisely identify the location of a thrombus, we use "the microcatheter contrast injection (MCI) technique," which accurately shows the proximal edge of a thrombus. We herein introduce this novel technique and discuss its efficacy in MT. Methods: In cases without the meniscus sign, a microcatheter was advanced to the distal end of contrast opacification, and contrast medium was injected through the microcatheter to detect the meniscus sign. An aspiration catheter was then advanced to the thrombus indicated by the meniscus sign and slowly withdrawn under aspiration. Results: 29 patients underwent MT for AIS using the MCI technique. Even in cases without the meniscus sign on initial angiography, the MCI technique accurately revealed the proximal edge of the thrombus. Moreover, middle cerebral artery occlusion due to atherosclerotic stenosis and displacement of the aspiration catheter and thrombus axis were detected using this technique. Conclusions: The MCI technique may effectively reveal the exact site of a thrombus and increase the success rate of first-pass recanalization.

Endovascular Treatment of Intracranial Aneurysms Using a Microcatheter Protection

PURPOSE

Stent protective or balloon remodeling techniques have enabled coil embolization of complexly configured aneurysms. Still, the utility of such methods may be limited in some small-caliber and/or inherently tortuous lesions. The present study was conducted to examine the efficacy of microcatheter protection (MCP) when applied in these circumstances.

METHODS

This retrospective review included 432 patients with 452 intracranial aneurysms subjected to MCP between April 2001 and January 2021. All available medical records and radiologic data were analyzed, focusing on strategic, safety, and efficacy aspects of the procedures.

RESULTS

In a majority (255/452, 56.4%) of cases, MCP was applied throughout entire coiling procedures, as opposed to coil framing (137/452, 30.3%) or filling/finishing (60/452, 13.3%) only. Lesions of the middle cerebral artery (54.9%) predominated, followed by anterior (12.4%) and posterior (11.1%) communicating artery aneurysms. Stent protection was also used occasionally (46/452, 10.2%). Procedural morbidity was low (3/432, 0.7%), limited to symptomatic thromboembolism and procedural leakage, and there were no deaths. Occlusion was successfully achieved by MCP in 424 aneurysms (93.8%). During the follow-up period (mean, 43.4 ± 30.4 months), satisfactory occlusion was documented in 406 of 440 (92.3%) aneurysms.

CONCLUSION

MCP is feasible and safe for coil embolization of intracranial aneurysms, in conjunction with multicatheter, balloon, or stenting techniques. MCP may have merit in small-sized or tortuous lesions not amenable to balloon or stent usage, often eliminating the need for stenting altogether.

Initial clinical experience with the Bendit steerable articulating tip microcatheter for intracranial access and intervention

BACKGROUND

The increasing complexity and sophistication of neurovascular implants and other therapeutic devices depend on access and delivery systems. Advancements in access technologies are required to improve minimally invasive endovascular procedures. Steerable catheters have been available in other disciplines, however, their implementation in neurovascular interventions has been a barrier previously due to issues with miniaturization and vascular caliber/complexity.

METHODS

A retrospective review of the neurovascular stroke database was conducted in accordance with local IRB to identify patients that received neurointerventional endovascular procedures using a novel first iteration 0.021'' microcatheter with controlled articulating tip flexion. Indications, management, demographics, comorbidities, and clinical and technical outcomes were recorded and analyzed. Primary operator feedback on the novel catheter was collected and reviewed.

RESULTS

Ten consecutive patients receiving treatment that involved a novel steerable 0.021'' microcatheter were identified and analyzed. No complications were reported. Novel useful features of the catheter were reported on a case-by-case basis.

CONCLUSIONS

Initial clinical experience with the controlled articulation that permits flexion at the tip of the microcatheter demonstrated it to be safe. Access to difficult proximal origin curves, and distal clinoidal/ophthalmic segment anatomy may be improved due to the high torque transmission, and acute angulation of this microcatheter. Further experience with the delivery of therapeutic devices will be necessary to better understand the potential role that the present catheter may play in modern neurointerventional procedures.

Microcatheter movement in the aneurysm due to low-profile visualized intraluminal support deployment: An in vitro study

BACKGROUND

When a microcatheter is in the aneurysm, it may move due to low-profile visualized intraluminal support (LVIS) deployment. This study was designed to determine this mechanism.

METHODS

Six silicon aneurysm models were created by combining the aneurysm location (side wall or bifurcation) and the parent vessel configuration (straight, ipsilateral bending, or contralateral bending). After adjusting the microcatheter tip position in the aneurysm by pushing or pulling, an LVIS stent was deployed to cover the aneurysm neck, and the changes in the microcatheter tip position was measured. Pushing and pulling were performed 15 times each for each model, for a total of 180 experiments.

RESULTS

In all experiments, the microcatheter tip moved with LVIS deployment. The total movement distance was 3.00±1.59 mm, which was significantly different between the push and pull groups (p = 0.049), between the three side-wall aneurysm models (p<0.0001), and between the three bifurcation aneurysm models (p<0.0001). Backward movement in the aneurysm occurred in 21% (37/180). The frequency of backward movement was significantly different between the side-wall and bifurcation aneurysm models (p = 0.0265) and between the push and pull groups (p<0.0001). The forward movement distance was significantly different between the side-wall (n = 78) and bifurcation (n = 65) aneurysm models (p<0.0001).

CONCLUSIONS

The aneurysm location, the parent vessel configuration, and adjustment of the microcatheter tip position by pushing or pulling may affect the total movement distance and forward/backward movement of the microcatheter tip due to LVIS deployment.

Coaxial Access for Microcatheter Stabilization During Aneurysm Coiling: 2-Dimensional Operative Video

Coaxial support is a fundamental technique utilized by neurointerventionalists to optimize distal catheter control within the intracranial circulation. Here we present a 41-yr-old woman with a previously coiled ruptured anterior communicating artery aneurysm with progressive recurrence harboring tortuous internal carotid anatomy to demonstrate the utility of coaxial support. Raymond-Roy classification of initial aneurysm coiling of class 1 resulted as class 3b over the 21 mo from initial treatment.1 The patient consented to stent-assisted coiling for retreatment of this aneurysm. Coaxial support was advanced as distally as possible in the proximal vasculature to improve catheter control, reducing dead space within which the microcatheter could move, decreasing angulations within proximal vasculature, limiting the movement of the native vessels, and providing a surface of lower friction than the endothelium. As the risk of recurrent subarachnoid hemorrhage in previously treated coiled aneurysms approaches 3%, retreatment occurs in 16.4% within 6 yr2 and in 17.4% of patients within 10 yr.3 Rerupture is slightly higher in patients who underwent coiling vs clipping, with the rerupture risk inversely proportional to the degree of aneurysm occlusion,4 further substantiating that coaxial support provides technical advantage in selected patients where additional microcatheter control is necessary for optimal occlusion. Pitfalls of this technique include vasospasm and vascular injury, which can be ameliorated by pretreatment of the circulation with vasodilators to prevent catheter-induced vasospasm. This case and model demonstration illustrates the technique of coaxial access in the stent-assisted coiling of a recurrent anterior communicating artery aneurysm and identification and management of catheter-induced vasospasm.

Distal Access to Wide-Necked Aneurysms-'Around the World' Technique: 2-Dimensional Operative Video

Wide-necked aneurysms often pose challenges for distal access to the distal vasculature. This 64-yr-old woman without neurological deficits presented with atypical headaches of gradual onset. MRI revealed a large, symptomatic, unruptured carotid terminus aneurysm incorporating the origin of both the middle (MCA) and anterior cerebral arteries (ACA). Its wide neck created significant risks to coil prolapse and parent vessel compromise, risking stroke. With other options of higher risks, we recommended an around-the-world technique. Standard transfemoral access was used to the right internal carotid artery (ICA) with a 6F-Shuttle sheath and intracranial carotid with a 6F-Sofia distal access catheter. With dual-microcatheter access, 1 catheter was placed in the aneurysm dome, a second in the MCA for stent placement. Advancing the wire around the aneurysm first formed a loop from the lateral to medial wall for access to the MCA. The microcatheter was then advanced around the wire into the MCA, keeping the loop within the dome. With the loop's distal tip anchored, the distal end of the stent was deployed and anchored into the MCA. Both pitfalls (ie, lack of sufficient distal access, collapse of stent device during deployment) were resolved using a balloon catheter. With the balloon positioned and inflated as the anchor, the wire and catheter were pulled together. The loop in the aneurysm's dome straightened out across the neck, the stent was advanced into the MCA, and coiling proceeded. A large neck remnant had partially closed on 6-mo follow-up angiogram. Patient consented to undergo the procedure. Illustrations in video published/printed with permission from Mayfield Clinic.

Hybrid microcatheter angioplasty for refractory cerebral vasospasm

Cerebral vasospasm is a significant cause of morbidity and mortality associated with aneurysmal subarachnoid hemorrhage (aSAH). Intra-arterial chemical and mechanical angioplasty, performed alone or in combination, have been shown to ameliorate cerebral vasospasm and improve patient outcomes. Few options exist for patients who fail these traditional endovascular tactics. We propose a hybrid microcatheter technique that combines the mechanical benefit of transient high pressure induced by microcatheter fluid bolus with a low-dose vasodilator infusion. Five patients with moderate to severe symptomatic vasospasm who failed medical and traditional endovascular management were treated using a hybrid microcatheter technique. All angioplasty procedures were technically successful, and the degree of vasospasm improved following angioplasty. There were no complications related to the cerebral angioplasty procedures. None of the patients required repeat endovascular intervention. Hybrid microcatheter angioplasty may be a useful complement to mechanical or pharmacological techniques in the endovascular management of intractable cerebral vasospasm after aSAH.

Endovascular Selective Intra-Arterial Infusion of Mesenchymal Stem Cells Loaded With Delta-24 in a Canine Model

BACKGROUND

Delta-24-RGD, an oncolytic adenovirus, shows promise against glioblastoma. To enhance virus delivery, we recently demonstrated that human bone marrow-derived mesenchymal stem cells loaded with Delta-24-RGD (hMSC-D24) can eradicate glioblastomas in mouse models. There are no studies examining the safety of endovascular selective intra-arterial (ESIA) infusions of MSC-D24 in large animals simulating human clinical situations.

OBJECTIVE

To perform canine preclinical studies testing the feasibility and safety of delivering increasing doses of hMSCs-D24 via ESIA infusions.

METHODS

ESIA infusions of hMSC-D24 were performed in the cerebral circulation of 10 normal canines in the target vessels (internal carotid artery [ICA]/P1) via transfemoral approach using commercially available microcatheters. Increasing concentrations of hMSC-D24 or particles (as a positive control) were injected into 1 hemisphere; saline (negative control) was infused contralaterally. Toxicity (particularly embolic stroke) was assessed on postinfusion angiography, diffusion-weighted magnetic resonance imaging, clinical exam, and necropsy.

RESULTS

ESIA injections were performed in the ICA (n = 7) or P1 (n = 3). In 2 animals injected with particles (positive control), strokes were detected by all assays. Of 6 canines injected with hMSC-D24 through the anterior circulation, escalating dose from 2 × 106 cells/20 mL to 1 × 108 cells/10 mL resulted in no strokes. Two animals had ischemic and hemorrhagic strokes after posterior cerebral artery catheterization. A survival experiment of 2 subjects resulted in no complications detected for 24-h before euthanization.

CONCLUSION

This novel study simulating ESIA infusion demonstrates that MSCs-D24 can be infused safely at least up to doses of 1 × 108 cells/10 mL (107 cells/ml) in the canine anterior circulation using commercially available microcatheters. These findings support a clinical trial of ESIA infusion of hMSCs-D24.

Factors related to microcatheter passage through the trans-cell approach using a low-profile visualized intraluminal support device: an in-vitro study

BACKGROUND AND PURPOSE

The trans-cell approach using a low-profile visualized intraluminal support (LVIS) device is sometimes used for aneurysm coil embolization. However, factors related to microcatheter passage remain uninvestigated. We aimed to examine in-vitro factors related to microcatheter passage using the trans-cell approach with an LVIS.

METHODS

Silicone vessel models (inner diameter, 4 mm) were created with different bend segments and a 4-mm hole assuming an aneurysm neck on the side of the greater curvature. The LVIS Blue (4.5 × 32 mm) was deployed at the bend segment, and passability on the trans-cell surface was evaluated by passing the microcatheter along the micro guidewire. A total of 800 passage experiments were performed using two types of microcatheter, ten types of silicone vessel, four cell widths, five cells with the same LVIS device, and two micro guidewire directions in the aneurysm.

RESULTS

The Headway Duo microcatheter (35.5%, 142/400) tended to have better passability compared with the Headway 17 microcatheter (29.3%, 117/400) (p = 0.070). As the cell width and angle between the trans-cell surface and microcatheter direction increased, passability significantly increased (p = 0.027 and p < 0.001, respectively). There was no significant difference in passability when the micro guidewire was directed to the proximal side versus the distal side (p = 0.45).

CONCLUSIONS

A large cell width and an obtuse angle between the trans-cell surface and microcatheter direction facilitated good passability. Although statistically marginal, microcatheters with small ledges and small tips had relatively good passability.

Coil embolization of renal artery aneurysms: Simultaneous delivery of three microdevices with a novel 6-Fr guiding sheath

Here, we report the case of a 59-year-old male patient who underwent transcatheter embolization of bilateral renal artery aneurysms, using 2 microballoons and 1 microcatheter, all carried within a single guiding sheath. During coil embolization in a visceral artery, there are situations that can require multiple microdevices. We developed a new 6-Fr Shephard-hook type guiding sheath (Parent Plus 60) with a lumen large enough to deliver three microdevices simultaneously. This technique can be used broadly in different clinical scenarios, and it may provide novel treatment strategies to clinicians in the future.

COILUMICA: coil embolization of a coronary artery to pulmonary artery fistula via novel dual lumen micro catheter technique

Background

Management of coronary artery fistula (CAF) is based on obliterating the fistula communication between the cardiac arteries and other thoracic vessels.

Case presentation

We describe the presentation of an 85-year-old female with progressive exertional dyspnea on a background of a long standing left anterior descending diagonal to pulmonary artery fistula. We utilized neuro-interventional techniques to perform coil embolization via use of a Scepter XC dual lumen micro catheter.

Conclusions

Dual lumen balloon catheters allow for super-selective artery interrogation, stability of balloon positioning, with less trauma to vessel architecture and accurate embolization. There were no complications and the patient reported improvement of symptoms on review.

Influence of Microcatheter Position on First-pass Success of Thrombectomy for Acute Ischemic Stroke

OBJECTIVE

In acute ischemic stroke, patient outcomes can be improved by first-pass successful recanalization of the occluded vessel. This study investigated whether microcatheter position could influence the success of first-pass recanalization.

METHODS

We retrospectively analyzed 59 consecutive acute ischemic stroke patients who underwent intra-arterial thrombectomy with stent retrievers for middle cerebral artery (M1) occlusion. Angiography findings obtained via the first pass of the microcatheter were analyzed. The microcatheter was considered to be inserted into M2 segments that gave rise to parietal arteries (M2P) if the anterior or posterior parietal artery was observed. Recanalization results were compared between patients with and without microcatheter insertion into M2P. The angle and diameter of vessels were measured using post-procedural magnetic resonance angiography.

RESULTS

The rate of first-pass successful recanalization (modified thrombolysis in cerebral infarction score of ≥2b) was significantly higher in patients with microcatheter insertion into M2P than in those without (56% vs. 22%, P = 0.016). The number of passes was lower in patients with first-pass microcatheter insertion into M2P than in those without (1.8 ± 1.0 vs. 2.5 ± 1.5, P = 0.05). The mean diameter of M2P was significantly larger than that of the other M2 (1.9 ± 0.6 mm vs. 1.7 ± 0.5 mm, P = 0.035). The M1/M2P angle was significantly smaller than that between M1 and the other M2. (49° ± 32° vs. 67° ± 31°, P = 0.006).

CONCLUSIONS

First-pass microcatheter insertion into M2P may contribute to fast successful recanalization in patients with M1 occlusion who undergo intra-arterial thrombectomy using stent retrievers.

Retreatment of a recanalized splenic artery aneurysm using a low-profile microembolization platform

Recanalization of a splenic artery aneurysm owing to incomplete transcatheter coil embolization is uncommon. In addition to the challenges of inherent vessel tortuosity, reintervention via catheterization of the main splenic artery presents unique difficulties in navigating across potentially obstructive preexisting coils. We describe here the application of a low-profile microembolization platform, most commonly used in neurovascular interventions, in the treatment of a tortuous, expanding splenic artery aneurysm that had previously undergone failed coil embolization.

[Safety indices for chronic total occlusion recanalisation by antegrade approach without scheduled contralateral injection: A consecutive series of 39 cases]

INTRODUCTION

Current guidelines for chronic total occlusion (CTO) percutaneous coronary intervention (PCI) recommend dual coronary angiography.

AIM OF THE STUDY

Evaluate CTO-PCI with a single approach using safety indices through the microcatheter.

POPULATION AND METHODS

Prospective observational study with a consecutive inclusion of 39 patients (mean age of 67 years) treated by antegrade approach without scheduled contralateral angiography. Following safety indices were collected: blood backflow, distal coronary pressure waveform, selective distal contrast injection.

RESULTS

Technical success was obtained in 90% of the cases. Balloon dilation was used in 38% of the cases before placement of the microcatheter. Dual angiography was necessary in three cases (8%). A blood backflow and cyclic changes of the distal coronary pressure waveform were noticed in 87% and 84% of the cases, with a positive predictive value of 97% and 79% respectively, for a microcatheter location in the true lumen. Selective distal contrast injection was done in 36 cases with a visualization of the true lumen in 35 cases. One major complication was observed (3%).

CONCLUSION

CTO-PCI with a single approach is feasible using safety indices to limit the risks of major complication. The principle of a systematic dual angiography as advocated in current guidelines may deserve to be revisited.

Embolic Agents and Microcatheters for Endovascular Treatment of Cerebral Arteriovenous Malformations

Endovascular embolization of cerebral arteriovenous malformations (AVMs) originally entailed delivery of N-butyl cyanoacrylate glue to the nidus via a flow-directed microcatheter. Within the past decade, several new liquid embolic agents and novel microcatheter technologies have become available that have improved the ease of use and efficacy of endovascular therapies for AVMs. Nonadhesive copolymers, such as Onyx and Precipitating Hydrophobic Injectable Liquid, have largely replaced N-butyl cyanoacrylate given a lower risk of catheter entrapment. The emergence of balloon microcatheters has allowed for improved protection of the normal cerebral vasculature and has improved the penetration of liquid embolics into large AVMs, ultimately reducing procedure times and radiation exposure. Finally, several detachable tip microcatheters have been developed to facilitate removal of the catheter from hardened liquid embolic cast, preventing the morbidity associated with distal catheter entrapment. This article reviews the embolic agents and microcatheters currently available for the treatment of cerebral AVMs in the United States as well as the data demonstrating the safety and efficacy of these devices.

Modified Viscotrabeculotomy with Microcatheter: Our Technique and Experience in the Surgical management of Glaucoma

Aims

To present the results of our case series with a technique we defined as “modified viscotrabeculotomy” which incorporates the benefits of 360° of trabeculotomy and viscodilation and viscodissection of canal of Schlemm using a microcatheter.

Materials and methods

This study was designed as a prospective interventional case series and was conducted in Cerrahpasa Medical School Ophthalmology Clinic. Forty-one eyes of 30 patients diagnosed with congenital glaucoma (CG) underwent modified viscotrabeculotomy surgery following initial preoperative examination. The main outcome measure was the surgical success of the procedure, which is determined by an intraocular pressure (IOP) of <18 mm Hg without medication or resurgery; qualified success is defined as an IOP of <18 mm Hg under general anesthesia with an additional need for medications. The differences in IOP measurements were analyzed using paired analysis of variance (ANOVA) with repeated measures.

Results

The mean preoperative IOP of the patients was 32.27 ± 4.89 mm Hg. The IOP values at the 1st, 3rd, 6th postoperative months, and at the last visit were 13.41 ± 2.25 mm Hg, 13.70 ± 1.78 mm Hg, 12.47 ± 1.57 mm Hg, and 12.26 ± 1.81 mm Hg, respectively. The difference between the preoperative IOP values and postoperative IOP values was statistically significant (p < 0.001). The qualified surgical success rate was 94.4% after a mean follow-up of 27.95 ± 8.25 months (range 15–45 months).

Conclusion

Modified viscotrabeculotomy is a safe and effective treatment in the management of CG.

How to cite this article

Tamçelik N, Capar O, Atalay E. Modified Viscotrabeculotomy with Microcatheter: Our Technique and Experience in the Surgical management of Glaucoma. J Curr Glaucoma Pract 2019;13(3):88–93.

Extent of the difference between microcatheter and pressure wire-derived fractional flow reserve and its relation to optical coherence tomography-derived parameters

Background

Although previous studies demonstrated that microcatheter-derived fractional flow reserve (mc-FFR) tends to overestimate lesion severity compared to pressure wire-derived FFR (pw-FFR), the clinical utility of mc-FFR remains obscure. The extent of differences between the two FFR systems and its relation to a lesion-specific parameter remain unknown. In this study, we sought to compare mc-FFR with pw-FFR and determine the lower and upper mc-FFR cut-offs predicting ischemic and non-ischemic stenosis, using an ischemic and a clinical FFR threshold of 0.75 and 0.80 as references, respectively. We further explored optical coherence tomography (OCT) parameters influencing the difference in FFR between the two systems.

Methods and results

In this study, 44 target vessels with intermediate de novo coronary artery lesion in 36 patients with stable ischemic heart disease were evaluated with mc-FFR, pw-FFR and OCT. Bland-Altman plots for mc-FFR versus pw-FFR showed a bias of −0.04 for lower mc-FFR values compared to pw-FFR values. The mc-FFR cut-off values of 0.73 and 0.79 corresponded to the 0.75 ischemic pw-FFR and 0.80 clinical pw-FFR thresholds with high predictive values, respectively. The differences in the two FFR measurements (pw-FFR minus mc-FFR) were negatively correlated with OCT-derived minimum lumen area (MLA) (R = −0.359, p = 0.011). The OCT-derived MLA of 1.36 mm² was a cut-off value for predicting the clinically significant difference between the two FFR measurements defined as >0.03.

Conclusion

Mc-FFR is clinically useful when the specific cut-offs are applied. An OCT-derived MLA accounts for the clinically significant difference in FFR between the two systems.

Successful percutaneous retrieval of a detached microcatheter tip using the guide-extension catheter trapping technique: A case report

A 55-year-old male with stable angina pectoris was referred to our hospital. Coronary angiography showed severe stenosis from the proximal to the middle part of the left circumflex artery (LCX). Based on the severity of lesion calcification, we performed percutaneous coronary intervention with rotational atherectomy. After crossing a 0.014-inch guidewire, we replaced it with a rotawire using a microcatheter. Following the retrieval of the microcatheter, we noted that a radiopaque tip of the microcatheter had been detached at the site of severe stenosis in the proximal part of the LCX. We advanced a guide-extension catheter to this site and wedged the detached tip using a balloon catheter (2.0-mm diameter; 12-mm length) in the guide-extension catheter. The detached tip was successfully retrieved along with the guide-extension catheter. After passing two guidewires into the main vessel and the side branch, we dilated the lesion using a 2.5-mm non-compliant balloon. Finally, we implanted two sirolimus-eluting stents, followed by post-dilatation with a 3.75-mm non-compliant balloon. This approach resulted in excellent dilatation and blood flow. Use of the guide-extension catheter trapping technique (i.e. use of a guide-extension catheter and a small balloon catheter) resulted in the successful percutaneous retrieval of a detached microcatheter tip. <Learning objective: We occasionally encounter adverse events related to the detachment or breakage of devices when performing percutaneous coronary intervention. The guide-extension catheter trapping technique using a guide-extension catheter and a small balloon is a useful approach for the retrieval of dislodged or entrapped devices.>.

Simmons Angled microguidewire INsertion to the Target (SAINT) technique in neuroendovascular therapy

Advancing appropriate microcatheters is essential for treatment. However, we still encounter inaccessible arterial branches because of the anatomical arrangement. While many successful techniques regarding microcatheters have been reported, there have been very few reports of microguidewire-shaping techniques. We developed the Simmons-Angled microguidewire INsertion to the Target (SAINT) technique for insertion of the microguidewire into inaccessible arterial branches. The SAINT technique is feasible for selection and insertion into arteries that are inaccessible with conventional methods.

A Case-Based Illustration of the Use of Microcatheter Pressure Transduction for Confirmation of Distal Wire Position in Complex Percutaneous Coronary Intervention

Determining distal wire position during chronic total occlusion percutaneous coronary intervention can be challenging. We describe a novel technique that can help confirm distal true lumen wire position. A microcatheter is advanced distally over the wire and after removing the guidewire, it is connected to a manifold for pressure transduction: an arterial waveform is indicative of intra-luminal position.

Microcatheter-assisted stenting of the tortuous vertical ductus arteriosus via femoral access in a duct-dependent pulmonary circulation

BACKGROUND

Stenting of the patent ductus arteriosus (PDA) has been accepted as alternative option to surgical shunting to enable additional pulmonary blood flow or for palliation of patients with a truly duct-dependent pulmonary circulation. The procedure can be challenging given the variable and often tortuous anatomy of the PDA and various technical approaches are reported.

OBJECTIVE

To report an alternative technique to treat tortuous ducts with microcatheter assistance and by transfemoral approach.

METHODS

We applied this technique of PDA stenting in 5 consecutive patients (4/5 age < 1 week, weight 2,7-3,2 kg; 1/5 re-do PDA stenting at 6,5 month and 5,9 kg). A soft coronary guidewire was advanced by microcatheter assistance into the branch pulmonary arteries and thereafter replaced by an extrastiff guidewire to enable the placement of long coronary stents.

RESULTS

Successful PDA stenting with this stepwise approach and with femoral access only could be achieved in all patients (n = 5/5). A single stent was used in 2 patients (one with re-do stenting and previous stents). 3/5 patients had 2 stents implanted by telescopic technique. Stent sizes used were 4,5 × 15 mm (n = 2) and 4,5 × 18 mm (n = 6). No guide wire or stent dislodgement appeared through all procedures with microcatheter assistance.

CONCLUSIONS

This technique enables PDA stenting via transfemoral approach in complex and tortuous ducts and thereby offers an attractive addition to the interventional management of truly duct-dependent pulmonary circulation.

Recent advances in microcatheter technology for the treatment of chronic total occlusions

INTRODUCTION

Use of a microcatheter is essential for chronic total occlusion (CTO) percutaneous coronary intervention (PCI). Several microcatheters have recently been introduced in clinical practice aiming to improve deliverability and resistance to deformation. Areas covered: We review the technical characteristics of several new microcatheters (Mamba, Mamba Flex, Teleport Control, Teleport, Nhancer Rx, Sasuke, and ReCross) and compare them with existing microcatheters. Expert opinion: The recently developed microcatheters offer additional options for guidewire support during CTO PCI. Accumulation of clinical experience and performance of comparative effectiveness studies are needed for better understanding the role of these devices in contemporary CTO PCI.

Use of microcatheters for suction thrombectomy of acute distal occlusions

We report our initial experience of using a microcatheter for contact aspiration of acute distal occlusions for recanalization. Endovascular technique and a case using Excelsior XT-27 microcatheter are presented. After manual suction within distal middle cerebral artery segments using a 50-ml syringe, instant and complete recanalization was obtained. Microcatheter suction thrombectomy using a 50-ml syringe can be considered a feasible treatment option for acute distal small artery occlusions.

Pericallosal aneurysm coiling with a "hubbed" 167 cm 0.013″ headway duo via a transradial approach

Cerebral aneurysms in patients with extreme proximal tortuosity may contraindicate endovascular therapy as a result of both the approach and an inability to navigate a coil-compatible microcatheter into the aneurysm due to microcatheter length. We present a 72 year-old male with multiple medical comorbidities admitted with a grade 3, ruptured pericallosal aneurysm. Aortoiliac disease contraindicated a transfemoral approach and thus a 6 French 105 cm guide catheter was advanced through a 6 French short radial sheath into a bovine left common carotid artery. After straightening proximal access anatomy with an Amplatz wire to allow advancement of the guide catheter into the internal carotid artery, a 167 cm 0.013 in. headway duo was advanced through a 5 French Sofia through the guide catheter and "hubbed" to enter the aneurysm. The aneurysm was then successfully coil embolized with 4 Target Ultrasoft coils. This case illustrates the utility of a 167 cm microcatheter for coil embolization of a pericallosal aneurysm with significant proximal tortuosity via a transradial approach. Despite its 0.013 in. inner diameter and length, common Target coils were compatible and deployed without incident.

Usefulness of the twin guidewire method during retrieval of the broken tip of a microcatheter entrapped in a heavily calcified coronary artery

During percutaneous coronary intervention performed for a stenotic lesion with heavy calcification in the left coronary artery, the microcatheter tip became transected in the vessel. The fragment was successfully retrieved using the twin guidewire method after negotiating to cross a chronic total occlusion-dedicated guidewire outside the retained tip.

Arterial embolizations with microvascular plug in extracranial and intracranial districts: technical results

PURPOSE

A new detachable microvascular plug (MVP, Reverse Medical^®, Irvine, CA, USA) has been recently developed; three models are available according to the size (MVP3-MVP5-MVP7). MVP3 and MVP5 are released through a 0.027″ microcatheter, MVP7 through a 4 Fr catheter. This series aims to describe an initial single-center experience examining intraprocedural safety and technical success of MVP.

MATERIALS AND METHODS

Ten patients (mean age 55.1 years) have been treated for arterial embolization using MVP; eight extracranial and two intracranial arterial embolizations have been performed. The embolizations were because of: four bleedings, three aneurysms, two pseudoaneurysms, and one presurgical nephrectomy.

RESULTS

MVP3 was used in five cases, MVP5 in four cases, and MVP 7 once. In all cases, the MVP was successfully released in < 1 min. In six patients, the MVP was the sole embolizing agent employed, while in four subjects, it was positioned complementary after coils. The technical and clinical success was obtained in 100%; hemorrhages were interrupted and aneurysms and pseudoaneurysms did not show recanalization at follow-up.

CONCLUSIONS

MVP seems to be a safe embolizing device that interventional radiologists should consider when facing arterial embolization of both body and neuroarterial districts; the main advantage is related to MVP3 and MVP5 models that can be adopted for distal embolization thanks to the precise release through 0.027″ microcatheter.

The Interference Phenomenon of Microcatheters in the Jailing Treatment for Internal Carotid Artery Side Wall Aneurysms with an Open Cell Stent System

Objective

Excelsior XT-27 (Stryker Neurovascular, Fremont, CA, USA) or Rebar 27 (eV3 Covidien, Irvine, CA, USA) microcatheters have recently been used to overcome the limitations of the Renegade Hi-Flo microcatheter such as interference between two microcatheters (one for stent delivery and the other for cerebral aneurysm coiling) during the jailing technique. We evaluated differences and influential factors related to the interference phenomenon according to these two microcatheters group.

Materials and Methods

Between June 2011 and September 2013, the jailing technique was applied to 94 internal cerebral artery (ICA) aneurysms. The jailing technique with the Neuroform EZ stent system was performed using Renegade (n = 22), Rebar (n = 35), and XT-27 microcatheters (n = 37). In the Renegade Hi-Flo microcatheter group, the jailing technique was successful in 19/22 patients (86.4%) and interference between the two microcatheters occurred in 6/21 patients (28.6%). In the Rebar and XT-27 microcatheter group, the jailing technique was successful in 71/72 patients (98.6%) and interference between the two microcatheters occurred in 1/72 patients (1.4%).

Results

There was a significant difference in the interference between the two delivered microcatheters group (p-value < 0.000) and the carotid siphon angle (p-value: 0.004) in the univariate analysis. In the multiple logistic regression analysis, the Rebar and XT-27 microcatheter group (odds ratio [OD] [95% confidence interval (CI)]; 31.277 [3.138-311.729], p-value: 0.003) and the carotid siphon angle (OD [95%CI]; 0.959 [0.922-0.997], p-value: 0.035) were found to be influential factors in the interference phenomenon.

Conclusion

The Rebar 27 and XT-27 microcatheters were more successful and exhibited less interference between the two microcatheters than the Renegade Hi-Flo microcatheter.

A novel side branch protection technique in coronary stent implantation: Jailed Corsair technique

Side branch occlusion, which was one of the common complications in percutaneous coronary interventions, was closely associated with cardiac death and myocardial infarction. Clinical guidelines also support the importance of preservation of physiologic blood flow in SB during PCI to bifurcation lesions. In order to avoid side branch occlusion during stent implantation, we often performed the jailed wire technique, in which a conventional guide wire was inserted to the side branch before stent implantation to the main vessel. However, the jailed wire technique could not always prevent side branch occlusion. In this case report, we described a case of 72-year-old male suffering from angina pectoris. Coronary angiography revealed the diffuse calcified stenosis in the proximal and middle of left anterior descending coronary artery, and the large diagonal branch originated from the middle of the stenosis. To prevent side branch occlusion, we performed a novel side branch protection technique by using the Corsair microcatheter (Asahi Intecc, Nagoya, Japan). In this case report, we illustrated this "Jailed Corsair technique", and discussed the advantage compared to other side branch protection techniques such as the jailed balloon technique.

Stenting After Coiling Using a Single Microcatheter for Treatment of Ruptured Intracranial Fusiform Aneurysms with Parent Arteries Less Than 1.5 mm in Diameter

BACKGROUND

Ruptured intracranial fusiform aneurysms involving small-diameter parent arteries are difficult to treat. Parent artery occlusion is a relatively simple and reliable treatment. However, occasionally, the parent arteries have to be retained. The arrival of the low-profile stent (LVIS Jr.) has made reconstructive endovascular treatment for fusiform aneurysms involving small-diameter parent arteries possible.

CASE DESCRIPTION

This report describes an innovative method for stent-assisted coiling (stenting after coiling technique using only 1 microcatheter) and describes our initial experience and feasibility of this technique. However, this report carries all limitations of a technical case report of a single patient, including reproducibility, unknown potential of complications, absence of long-term follow-up, and comparative effectiveness or safety with current known techniques.

CONCLUSIONS

Stenting after a coiling technique using the LVIS Jr. stent provides a possible method for reconstructive endovascular treatment of intracranial fusiform aneurysms with parent arteries <1.5 mm in diameter.

Easy Advancement of a Large-Profile Microcatheter (Excelsior XT27™) by Parallel Use of Two Microguidewires For Stent Delivery

Purpose

In the endovascular treatment of cerebral aneurysms, navigating a large-bore microcatheter for delivery of an open-cell stent can be challenging, especially in wide-necked bifurcation aneurysms. We were able to overcome this difficulty by parallel use of two microguidewires through the stent-delivery microcatheter.

Materials and Methods

From December 2014 to April 2015, we treated 15 patients with wide-necked bifurcation aneurysms. For stent delivery, we used a 300-cm 0.014-in microguidewire (Transend), which was placed into the target branch using an exchange technique. A 0.027-in microcatheter (Excelsior XT-27), which was designed for the stent, was advanced over the exchange microguidewire. If we had trouble in advancing the microcatheter over the exchange microguidewire, we inserted a regular microguidewire (Traxcess), into the microcatheter lumen in a parallel fashion. We also analyzed the mechanism underlying microcatheter positioning failure and the success rate of the 'parallel-wire technique'.

Results

Among the 15 cases, we faced with navigation difficulty in five patients. In those five cases, we could advance the microcatheter successfully by applying the parallel-wire technique. There were no procedure-related complications.

Conclusion

Simply by using another microguidewire together with pre-existing microguidewire in a parallel fashion, the stent-delivery microcatheter can be easily navigated into the target location in case of any advancement difficulty.

Microcatheter Looping to Facilitate Aneurysm Selection in Coil Embolization of Paraclinoid Aneurysms

Objective

Described herein is a microcatheter looping technique to facilitate aneurysm selection in paraclinoid aneurysms, which remains to be technically challenging due to the inherent complexity of regional anatomy.

Materials and Methods

This retrospective study was approved by our Institutional Review Board, and informed consent was waived. Microcatheter looping method was employed in 59 patients with paraclinoid aneurysms between January 2012 and December 2013. In the described technique, construction of a microcatheter loop, which is steam-shaped or pre-shaped, based on the direction of aneurysms, is mandatory. The looped tip of microcatheter was advanced into distal internal carotid artery and positioned atop the target aneurysm. By steering the loop (via inner microguidewire) into the dome of aneurysm and easing tension on the microcatheter, the aneurysm was selected. Clinical and morphologic outcomes were assessed with emphasis on technical aspects of the treatment.

Results

Through this looping technique, a total of 59 paraclinoid aneurysms were successfully treated. After aneurysm selection as described, single microcatheter technique (n = 25) was most commonly used to facilitate coiling, followed by balloon protection (n = 21), stent protection (n = 7), multiple microcatheters (n = 3), and stent/balloon combination (n = 3). Satisfactory aneurysmal occlusion was achieved through coil embolization in 44 lesions (74.6%). During follow-up of 53 patients (mean interval, 10.9 ± 5.9 months), only one instance (1.9%) of major recanalization was observed. There were no complications related to microcatheter looping.

Conclusion

This microcatheter looping method facilitates safe and effective positioning of microcatheter into domes of paraclinoid aneurysms during coil embolization when other traditional microcatheter selection methods otherwise fail.

Jailing Technique Using a Catheter-based Open-cell Stent System in Internal Carotid Artery Sidewall Aneurysms Unfeasible to Simple Coiling

Objective

An open cell stent system may offer better apposition of cell struts to vessel wall than a closed cell stent system in acute vasculature. The purpose of this study was to evaluate the feasibility of coiling using the jailing technique with the Neuroform EZ stent system.

Methods

The jailing technique using the open-cell stent system of the Neuroform EZ stent was planned in 22 consecutive patients with 22 cerebral aneurysms. We retrospectively evaluated the technical success of the jailing technique and the occurrence of interference between two microcatheters as well as the factors influencing this interference.

Results

The jailing technique was successful in 19/22 patients (86.4%), and interference between two microcatheters occurred in 6/21 (28.6%). The jailing technique failed in 3/22 patients, with problems that included failure of the stent delivery system to advance into the positioned microcatheter in one, interference between the microcatheters during the advancement of the stent delivery system in one, and failure of microcatheter insertion into the aneurysm sac in the remaining patient. Interference between the two microcatheters developed during the advance of the stent delivery system into the positioned microcatheter in all cases. One factor that influences interference between two microcatheters more than expected by chance is the carotid siphon angle (p = 0.019).

Conclusion

The acuteness of the carotid siphon angle influences the interference between two microcatheters. Therefore, the jailing technique using the Neuroform EZ stent should be performed carefully in cerebral aneurysms with an acute carotid siphon angle because the procedure may possibly fail.

Aneurysm coil embolization using a 1.5-fr distal outer diameter microcatheter

The current assortment of microcatheters widely used for aneurysm coil embolization may not be well suited for several anatomic variants, including excessive vascular tortuosity and small aneurysms less than 3 mm. Longer microcatheters designed with a smaller caliber that can accommodate and deliver coils may be of use in these situations. This case series and literature review illustrates the advantages and limitations of the Marathon microcatheter (Covidien, Irvine, CA, USA) when used for coil embolization of cerebral aneurysms. Despite some technical compromises including the distal marker, length, and the risk of buckling, the Marathon microcatheter was able to adequately deliver coils to achieve satisfactory occlusion of cerebral aneurysms. We found unique advantages with regards to length and smaller distal outer diameter (OD). These results may serve as a guide for the further development of a microcatheter used for coil embolization that has the features of a smaller distal OD and longer length.

Cannulation of the internal carotid artery in mice: a novel technique for intra-arterial delivery of therapeutics

We have developed a novel minimally invasive technique for the intra-arterial delivery of therapeutics to the mouse brain. CD-1 mice were anesthetized and placed in a lateral decubitus position. A 10mm midline longitudinal incision was made over the thyroid bone. The omohyoid and sternomastoid muscles were retracted to expose the common carotid artery and external carotid artery (ECA). To maximize delivery of administered agents, the superior thyroid artery was ligated or coagulated, and the occipital artery and the pterygopalatine artery (PPA) were temporarily occluded with 6-0 prolene suture. The ECA was carefully dissected and a permanent ligature was placed on its distal segment while a temporary 6-0 prolene ligature was placed on the proximal segment in order to obtain a flow-free segment of vessel. A sterilized 169 μm outer diameter polyimide microcatheter was introduced into the ECA and advanced in retrograde fashion toward the carotid bifurcation. The catheter was then secured and manually rotated so that the microcatheter tip was oriented cephalad in the internal carotid artery (ICA). We were able to achieve reproducible results for selective ipsilateral hemispheric carotid injections of mannitol mediated therapeutics and/or gadolinium-based MRI contrast agent. Survival rates were dependent on the administered agent and ranged from 78 to 90%. This technique allows for reproducible delivery of agents to the ipsilateral cerebral hemisphere by utilizing anterograde catheter placement and temporary ligation of the PPA. This method is cost-effective and associated with a low rate of morbimortality.

Three benefits of microcatheters for retrograde transvenous obliteration of gastric varices

AIM: To evaluate the usefulness of the microcatheter techniques in balloon-occluded retrograde transvenous obliteration (BRTO) of gastric varices.

METHODS: Fifty-six patients with gastric varices underwent BRTOs using microcatheters. A balloon catheter was inserted into gastrorenal or gastrocaval shunts. A microcatheter was navigated close to the varices, and sclerosant was injected into the varices through the microcatheter during balloon occlusion. The next morning, thrombosis of the varices was evaluated by contrast enhanced computed tomography (CE-CT). In patients with incomplete thrombosis of the varices, a second BRTO was performed the following day. Patients were followed up with CE-CT and endoscopy.

RESULTS: In all 56 patients, sclerosant was selectively injected through the microcatheter close to the varices. In 9 patients, microcoil embolization of collateral veins was performed using a microcatheter. In 12 patients with incomplete thrombosis of the varices, additional injection of sclerosant was performed through the microcatheter that remained inserted overnight. Complete thrombosis of the varices was achieved in 51 of 56 patients, and the remaining 5 patients showed incomplete thrombosis of the varices. No recurrence of the varices was found in the successful 51 patients after a median follow up time of 10.5 mo. We experienced one case of liver necrosis, and the other complications were transient.

CONCLUSION: The microcatheter techniques are very effective methods for achieving a higher success rate of BRTO procedures.

Dual microcatheter retrograde transvenous obliteration of gastric varices: coil embolization as a substitute for balloon occlusion

Dual microcatheter retrograde transvenous obliteration (DMRTO) of gastric varices enables dual microcatheters to be advanced to the gastric varices themselves or to a site adjacent to the varices. The sclerosing agent is infused through the first microcatheter following coil embolization of the outflow vessels through the second microcatheter, which is placed several centimeters back from the varices. We present two cases of gastric varices in whom balloon-occluded retrograde transvenous obliteration failed, because of angulated gastrosubphrenic shunt in case 1 and a tortuous and elongated gastrorenal shunt in case 2. DMRTO successfully achieved eradication of the gastric varices in both cases.

Usefulness of microcatheters inserted overnight for additional injection of sclerosant after initial balloon-occluded retrograde transvenous obliteration of gastric varices

In patients with large gastric varices, dose limitation of the sclerosant can cause difficulties in achieving complete thrombosis of varices during a single balloon-occluded retrograde transvenous obliteration (BRTO) procedure. For patients with incomplete variceal thrombosis after the first BRTO, additional sclerosant must be injected in a second BRTO. We report a successful case of BRTO for large gastric varices in whom additional sclerosant was injected through a microcatheter that remained inserted overnight. To achieve complete variceal thrombosis in a patient with incomplete thrombosis of large gastric varices after a first BRTO, a retained microcatheter can be used to inject additional sclerosant in a second BRTO the next day.