33 Aspiration-Retriever Technique for Stroke (ARTS)
33.1 Case Description
33.1.1 Clinical Presentation
An 85-year-old male presented with sudden onset of confusion, speech difficulties, and right-sided weakness, predominantly in the face and arm. He was last seen well 1 hour prior by his wife. Neurological examination revealed he was disoriented and aphasic. He had left gaze preference associated with right hemianopsia. There was a right, upper motor neuron facial palsy with absent movement in the right arm and mild weakness in the right leg (able to sustain suspended against gravity). His National Institutes of Health Stroke Scale (NIHSS) score was 20.
Noncontrast computed tomography (CT) of the head showed only subtle loss of grey-white differentiation in the anterior frontal region (M1) consistent with an Alberta Stroke Program Early CT (ASPECTS) score of 9. CT angiography demonstrated a left M1 segment occlusion with corresponding nonmatched perfusion defect on CT perfusion (Fig. 33.1).
He was not a candidate for tissue plasminogen activator, as his current medications included low-dose apixaban and aspirin for deep venous thrombosis prophylaxis in the setting of malignancy and cardiac disease. Mechanical thrombectomy was pursued (Fig. 33.2).
Pretreatment left internal carotid artery (ICA) injection showed persistent occlusion.
Lateral view of the microcatheter injection demonstrated distal access beyond the M1 thrombus. The microcatheter was supported by a balloon guide catheter (BGC) within the distal cervical ICA and a distal aspiration catheter whose tip was positioned in the mid-M1 segment (Fig. 33.3).
Unsubtracted oblique view following deployment of the stentriever device (Trevo XP ProVue 4 × 30 mm) and removal of the microcatheter. The distal aspiration catheter (ACE68, Penumbra) remained in the proximal M1 segment, at the proximal end of the stent, to engage the thrombus (Fig. 33.4).
Postmechanical thrombectomy anteroposterior (left) and lateral (right) views demonstrated complete reperfusion (Fig. 33.5).
33.1.4 Endovascular Devices
9-Fr 80-cm Teleflex Arrow-Flex sheath.
9-Fr 92-cm Medtronic Cello BGC.
Penumbra 5-Fr 130-cm Berenstein Select catheter.
Terumo Advantage Glidewire 180 cm.
Penumbra ACE 68 reperfusion catheter 132 cm.
Penumbra Velocity Delivery microcatheter 170 cm.
Boston Scientific Fathom 16 180 cm microwire.
Stryker Trevo XP ProVue 4 mm × 30 mm stent.
Thrombolysis in cerebral infarction (TICI) 3 reperfusion was achieved after a single stentriever pass. Clinically, his right arm improved to 4+/5 in strength with a minor pronator drift and right leg to 5/5 strength. He had persisting partial aphasia and a right facial droop. He was transferred to a peripheral hospital for rehabilitation.
The advent of stent retrievers and their utilization in acute ischemic stroke has revolutionized endovascular treatment of proximal intracranial large vessel occlusions. These in combination with large bore, distal access aspiration catheters have led to the development of a variety of techniques to promote mechanical thrombectomy success by increasing recanalization rates, decreasing the number of passes required, and shortening time to reperfusion while reducing thrombus fragmentation with subsequent distal embolization. The aspiration (catheter)-(stent) retriever technique for stroke (ARTS) was created to achieve these criteria. 1
For access, an 8- to 9-Fr BGC is used and positioned within the distal cervical ICA. A triaxial assembly is then established with a distal access aspiration catheter navigated over a 0.021- to 0.027-in microcatheter and 0.014- to 0.016-in microwire, which are navigated through the clot. The aspiration catheter is then brought close to the proximal end of the clot (either over the microcatheter or, if it does not track, later “railed” over the deployed stentriever). The microwire is removed; after a microcatheter injection to confirm suitable position, a stent retriever is unsheathed across the clot and given several minutes to incorporate. The microcatheter is then removed. Retrieval of the stent is initiated with inflation of the BGC, followed by continuous aspiration through the distal access catheter by means of a mechanical pump. The stent is then pulled; simultaneously, the aspiration catheter advances slightly until there is resistance or reduction in flow through the aspiration tubing at which point, the entire system is locked. One may then wait a few minutes to promote “corking” of the clot. Thereafter, the stent retriever and microcatheter are withdrawn simultaneously through the BGC. The principle of this treatment revolves around “corking” the aspiration catheter with the stent-ensnared clot followed by retrieval under continuous aspiration and flow arrest.
Using ARTS, Massari et al 1 were able to achieve TICI ≥ 2b/3 recanalization in 97.6% of 42 consecutive patients, a majority of which were anterior circulation and M1 occlusions. Of these recanalizations, 43% were successful on the first pass. Distal emboli occurred in 4.7% of patients downstream into a M3 or M4 branch, and 2.4% (1 patient) into a nontarget territory. The procedure was associated with four cases (9.5%) of symptomatic intracerebral hemorrhage (two subarachnoid hemorrhages secondary to stent retrieval and two intraparenchymal hemorrhages), which is comparable to the hemorrhagic complication rate observed in the multicenter randomized clinical trial of endovascular treatment for acute ischemic stroke in the Netherlands trial (MR CLEAN; 7.7%). At the 90-day follow-up, 65.7% of patients had a modified Rankin scale (mRS) score of ≤ 2, falling in the higher range of what was observed in the major stent-retriever trials from 2015 (32.6% in MR CLEAN to 71% in Extending the Time for Thrombolysis in Emergency Neurological Deficits—Intra-Arterial [EXTEND-IA] trial).
ARTS utilizes the advantages of stent retrieval and direct catheter aspiration by combining them in a synergistic manner. A key component of this technique is the partial recapturing of the stent into the distal aspiration catheter until the clot is “corked,” and simultaneous removal into the BGC, while maintaining this relationship rather than complete retrieval of the stent through the distal aspiration catheter as performed in SOLUMBRA and first described by Deshaies et al. 2 This minimizes the “apple-coring” effect that can occur as a large, ensnared clot/stent complex is forcefully withdrawn into the aspiration catheter. It is theorized that this action contributes to fragmentation of the clot and iatrogenic distal embolization. This is supported by a higher rate of new territory embolus in the series by Humphries et al 3 using SOLUMBRA (5.7%) compared to the series by Massari et al 2 using ARTS (2.4%).
The continuous aspiration prior to intracranial vascular embolectomy (CAPTIVE) technique of McTaggart et al 4 employs a similar method of stent retrieval; however, ARTS has the advantage of using a BGC. Inflation of the BGC initiates flow arrest which has been shown, in vitro, to reduce distal embolization during thrombectomy. 5 In practice, this has been observed to improve clinical and angiographic outcomes in patients with acute large vessel occlusion strokes. A recent systematic review compared stroke patients treated using mechanical thrombectomy with (1,083 patients) and without (939 patients) a BGC. 6 Use of BGC was associated with a higher first-pass recanalization rate (63.1 vs. 45.2%), greater chance of achieving TICI 2b/3 reperfusion (78.9 vs. 67%), less distal embolization evidenced by a higher TICI 3 rate (57.9 vs. 38.2%), and fewer number of passes (mean: 1.7 vs. 2.0). These patients also experienced improved clinical outcomes with a greater number achieving a 90-day mRS score of ≤ 2 (59.7 vs. 43.8%).
Both ARTS and CAPTIVE attempt to maximize the suction capabilities of the distal aspiration catheter through removal of the microcatheter after deployment of the stent retriever. The absence of a microcatheter not only increases the surface area for aspiration but also augments flow by increasing the volume accessible to fluid and reducing contact surfaces which contribute to drag forces. In vitro, Nikoubashman et al 7 were able to demonstrate that microcatheter absence (termed the “bare wire technique”) significantly increased the volume aspirated over time. This, in turn, enables improved blood flow control toward reversal (particularly in the setting of an inflated balloon guide), thereby reducing the clot disruption and distal embolization. Together, these maneuvers that comprise the ARTS technique build upon the fundamentals of stentriever use, as described in the original thrombectomy trials coupled with aspiration via an intermediate catheter close to the clot and flow arrest, hopefully translating to more effective large vessel recanalization therapy while minimizing the risks of nontarget embolization or clot release. However, a limitation to the earlier discussion is the lack of randomized trials comparing these techniques and hence the lack of comparisons based on retrospective data.