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Original research
Endovascular stroke therapy with the Aperio thrombectomy device
  1. Kai Kallenberg1,
  2. Laszlo Solymosi2,
  3. Christian A Taschner3,
  4. Joachim Berkefeld4,
  5. Marc Schlamann5,
  6. Olav Jansen6,
  7. Sebastian Arnold7,
  8. Bernd Tomandl8,
  9. Michael Knauth1,
  10. Bernd Turowski9
  1. 1Institute for Diagnostic and Interventional Neuroradiology, University Medical Center Göttingen, Göttingen, Germany
  2. 2Department of Neuroradiology, University Würzburg, Würzburg, Germany
  3. 3Department of Neuroradiology, University Medical Center Freiburg, Freiburg, Germany
  4. 4Institute for Neuroradiology, University Medical Center Frankfurt, J W Goethe-University Frankfurt, Frankfurt, Germany
  5. 5Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen, Essen, Germany
  6. 6Department of Radiology and Neuroradiology, UKSH Campus Kiel, Kiel, Germany
  7. 7Institute for Diagnostic and Interventional Radiology, Städtisches Klinikum Karlsruhe gGmbH, Karlsruhe, Germany
  8. 8Clinic for Radiology and Neuroradiology, Klinikum Christophsbad, Göppingen, Germany
  9. 9Section of Neuroradiology, Institute for Diagnostic and Interventional Radiology, University Düsseldorf, Düsseldorf, Germany
  1. Correspondence to Dr Kai Kallenberg, Diagnostic and Interventional Neuroradiology, Universtitätsmedizin Göttingen, Robert-Koch-Str. 40, Göttingen 37099, Germany; kai.kallenberg{at}med.uni-goettingen.de

Abstract

Background The pharmaceutical therapy for acute ischemic stroke has shortcomings in reopening large vessels and dissolving long thrombi, and endovascular treatment has been found to provide added value. The Aperio thrombectomy device showed promising results in an experimental study. The purpose of this study was to evaluate the device clinically.

Methods 119 patients with acute stroke were treated in nine centers using the Aperio thrombectomy device. Target vessel, diameter, thrombus length, procedure time, recanalization, number of deployments, additional use of anticoagulants, complications, and the use of additional devices were assessed.

Results The median thrombus length was 15 mm (range 1.5–20 mm) and the average time from device insertion to recanalization was 30 min (range 5–120 min). Blood flow restoration (Thrombolysis In Cerebral Infarction (TICI) 2–3) was achieved in 85%. In the majority of cases complete clot removal was achieved (TICI 0, 12%; TICI 1, 2%; TICI 2a, 14%; TICI 2b, 18%; TICI 3, 53%). The median number of deployments was 2 (range 1–6). Twelve procedural complications (10%) occurred.

Conclusions The Aperio thrombectomy device seems to be an effective and adequately safe tool for reopening occluded cerebral arteries in the setting of acute stroke.

  • Stroke
  • Thrombectomy
  • Device
  • Brain

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Introduction

Stroke is the second leading cause of death and the most important cause of disability in developed countries.1 The gold standard treatment of patients with ischemic stroke has been systemic thrombolysis within 4.5 h after onset of symptoms.2 Early treatment is an important predictor of good outcome,3 ,4 although reopening of the occluded vessel providing restoration of brain perfusion is required.5 However, recanalization rates of extracranial or proximal intracranial artery occlusions6 ,7 and the clearing of larger thrombi8 treated by intravenous thrombolysis alone are unsatisfactory. Here, intra-arterial therapy has proved to be more effective,5 ,7 ,9–11 and a number of methods have been used.12–18 The application of retrievable stent-like thrombectomy systems has been found to be superior to intravenous thrombolysis alone.19–23

Aperio (Acandis, Pforzheim/Germany) is a newer thrombectomy device which was found to remove blood clots as effectively as the market leading product in an experimental study, and faster and with less distal embolization than the other devices tested.24 Therefore, the aim of this study was to evaluate the practicability and effectiveness of this device in an ‘everyday anywhere clinical setting’: in multiple centers, applied by neurovascular interventionalists with different levels of experience.

Materials and methods

The study comprised patients with acute stroke treated in nine centers using the Aperio thrombectomy device. The patient triage, treatment decision, and procedure were performed according to local standards.

The Acandis Aperio device is a non-detachable mechanical thrombectomy device with a hybrid cell design. The device has an outer diameter of 4.5 mm and a usable length of 35–40 mm, depending on the vessel diameter. For radio-opacity, the device has two elongated wire markers to support the positioning of the device and three distal device markers to indicate the distal device end and the grade of expansion (figures 14). A 0.027 inch microcatheter (Neuroslider, Acandis, Pforzheim/Germany) was used for device placement in all cases.

Figure 1

The Aperio device. Top: drawing (from the company's official brochure). Bottom: photograph.

Figure 2

Digital subtraction angiography image of the completely released Aperio device positioned in M1 and M2 branch. Visible parts from distal to proximal are: (1) three distal device markers demonstrating complete expansion; (2) distal wire marker; (3) proximal wire marker; and (4) tip of the microcatheter.

Figure 3

Subtracted image: device only partly released.

Figure 4

Fluoroscopic image: device partly released.

The thrombus length was measured by digital subtraction angiography (DSA); a diagnostic microcatheter DSA series (figure 5) was performed to ascertain a position distal to the thrombus before the Aperio device was pushed through the microcatheter. After superpositioning of the distal markers of the catheter and the thrombectomy device, the device was released by pulling back the microcatheter. After a complete (or, in some cases, partial) deployment and an interval of usually 2–5 min in the open position, the device was pulled back while aspiration was applied to the guiding catheter. Additionally, in fewer than half of the cases—depending on individual preferences—an additional intermediate catheter was used in the telescope technique to enable ancillary local aspiration. Typically, 5 F intermediate catheters were used.

Figure 5

Digital subtraction angiography microcatheter series distal to the thrombus.

After each procedure the interventionalists were asked to rate their experience with the device regarding trackability, visualization, positioning, and deployment as: ++ very good, + good, 0 mediocre, − substandard, − − poor.

The data were reported in anonymized fashion by the neurointerventionalist and subsequently recorded in a custom-built database. The study was approved by the local ethic committees.

Results

A total of 119 patients with acute stroke (68 women, 51 men) were treated in nine centers with the Aperio thrombectomy device. In more than one-third of patients an occlusion of the carotid artery was treated (table 1). However, the minimal vessel diameter at the site of device deployment was rather narrow (table 2). The handling was rated as good or very good by the neurointerventionalists in the majority of cases (figures 69).

Table 1

Target vessel (N=119)

Table 2

Vessel diameter at the site of Aperio deployment

Figure 6

Neurointerventionalists’ individual case-specific experience of device trackability (++, very good; − −, poor).

Figure 7

Neurointerventionalists’ individual case-specific experience of device visualization (++, very good; − −, poor).

Figure 8

Neurointerventionalists’ individual case-specific experience of device deployment (++, very good; − −, poor).

Figure 9

Neurointerventionalists’ individual case-specific experience of device positioning (++, very good; − −, poor).

The median thrombus length was 15 mm (range 1.5–20 mm) and the average time from device insertion to recanalization was 30 min (range 5–120 min). Blood flow restoration (Thrombolysis In Cerebral Infarction (TICI) 2–3) was achieved in 85% of patients. In the majority of cases complete clot removal was achieved (TICI 0, 12%; TICI 1, 2%; TICI 2a, 14%; TICI 2b, 18%; TICI 3, 53%). The median number of deployments was 2 (range 1–6).

After use the catheters were flushed with heparinized saline. Only 17 patients (14%) did not receive any additional periprocedural anticoagulant medication. A specific body weight-adapted dose of recombinant tissue plasminogen activator (rtPA) was administered to 74 patients (62%). In 26 cases rtPA was given only intravenously (‘bridging’) and in 48 cases a combined intravenous/intra-arterial approach was applied. The remaining 28 patients received anticoagulant medication during the procedure only (11 intra-arterial rtPA, 15 heparin, 2 tirofiban).

Twelve procedural complications (10%) occurred (table 3): one vessel perforation with subarachnoid hemorrhage (SAH), one SAH of unknown cause, four cases of vasospasm, one device rupture, one case with subarachnoid contrast agent in post-interventional angiographic CT of unknown cause, and three dissections. The dissections affected the extracranial arteries only (two in the internal carotid artery and one in the vertebral artery). In one additional case the patient experienced a trauma with an open fracture of the forearm because of a fall attributed to the stroke. During the thrombectomy procedure the blood hemoglobin concentration decreased significantly so that a blood transfusion was required.

Table 3

List of complications with information concerning treatment and outcome

Embolization of previously unaffected territories by fragmented or lost clots was not reported in any case.

More than one thrombectomy device was used in 12 cases (10%) when the previously applied stent retriever was not successful. In 10 cases the Aperio was the first-line device. In three cases more than two devices from different manufacturers were used. In the majority (10/12) of the multi-device cases the target vessel remained occluded.

Discussion

Numerous studies have shown the value of rtPA in the treatment of acute stroke as a potent pharmaceutical therapy,3 although there is room for improvement as the overall patient outcome is still unsatisfactory.1 The relatively new technique of self-expanding retrievable stent systems17 offers a quick way to remove the occluding blood clot and subsequently to re-establish anterograde blood flow. The risk of thrombotic material diverting to previously unaffected arteries and so exceeding the stroke volume appears acceptably low,19 and is even lower with stent retrievers than with vacuum systems.25 In this regard, Saleh et al24 suggested that the Aperio system has an advantage compared with Solitaire and Revive. However, the retrievable stent devices may cause additional damage to the affected vessel wall. This effect also seems more pronounced when using vacuum systems,26 but overall the effect is negligible.27

Prospective randomized controlled trials have shown that the use of stent retrievers is safe and there is no additional risk of symptomatic intracranial hemorrhages or mortality compared with systemic rtPA, even if mechanical thrombectomy is performed in addition to pharmaceutical thrombolysis.28 In this study we report the use of the Aperio thrombectomy device with its distal portion mainly deployed in vessels of ≤2 mm diameter with fewer intracranial hemorrhages than with rtPA alone29 or with previous studies applying retrievable stent systems to treat acute stroke.19–21 In the MR-CLEAN trial there was no difference in the overall risk of any serious adverse event between the intervention group and the control group,19 but the risk was considerably higher than in the present study. Stent retrievers can be used without relevant additional risk but offer additional value —for example, thrombi >8 mm usually withstand systemic pharmacotherapy and occluded larger arteries often withstand systemic pharmacotherapy.6 ,8 Re-establishment of patency5 ,30 ,31 and early recanalization18 ,32 ,33 are positively correlated to a beneficial outcome.

The overall recanalization rate (≥TICI 2a) was 85%, which is similar to that of other trials evaluating retrievable stent systems such as SWIFT (Solitaire 89%, Merci 67%),34 SWIFT PRIME (Solitaire 88%),23 Trevo (Trevo 92%),18 Trevo II (Trevo 92%, Merci 77%),35 and IMS III (Merci 73%).36 However, to participate in these studies the neurointerventionalists had to fulfill certain qualification criteria whereas the experience of the physicians who used the Aperio device was quite inhomogeneous. The actual prospective randomized trials achieved revascularization rates of 90–93%.19–21

In 12 cases the neurointerventionalist decided to use two or more thrombectomy devices due to disappointing results with the first one. In 10 cases even the deployment of two or more devices did not lead to re-establishment of a persistent anterograde blood flow. In two cases the vessel was successfully reopened after several devices had been used. However, in one case SAH developed after the use of multiple devices. Additional attempts with different mechanical thrombectomy devices were thought to be responsible for additional complications associated with intracranial hemorrhage and death in the SWIFT trial.37

Conclusion

The Aperio thrombectomy device seems to be an effective and adequately safe tool for reopening occluded cerebral arteries in the setting of acute stroke.

References

Footnotes

  • Contributors All authors contributed to the conception of the work and the acquisition, analysis, and interpretation of data. They edited, revised, and finally approved the manuscript version to be published. They agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Competing interests KK participated in speakers’ bureau for Acandis during the conduct of the study and speakers’ bureau for Novartis Pharma GmbH outside the submitted work. JB received personal fees from Acandis during the conduct of the study. OJ received personal fees from Covidien and personal fees from Strykker outside the submitted work. MK participated in speakers’ bureaus for Penumbra, Bayer Healthcare, and Siemens Medical outside the submitted work. BT received personal fees from Acandis outside the submitted work.

  • Ethics approval The study was approved by the local ethics committees of all the centers involved.

  • Provenance and peer review Not commissioned; externally peer reviewed.