Complications of Endovascular Treatment for Acute Stroke in the SWIFT Trial with Solitaire and Merci Devices

BACKGROUND AND PURPOSE:Treatment of patients with ischemic stroke after endovascular treatment requires in-depth knowledge of complications. The goal of this study was to make endovascular treatment for acute ischemic stroke safer through an in-depth review of the major periprocedural complications observed in the Solitaire FR With Intention for Thrombectomy (SWIFT) trial.MATERIALS AND METHODS:The SWIFT data base was searched for major peri-procedural complications defined as symptomatic intracranial hemorrhage within 36 hours, SAH, air emboli, vessel dissection, major groin complications, and emboli to new vascular territories.RESULTS:Major peri-procedural complications occurred in 18 of 144 patients (12.5%) as follows: symptomatic intracranial hemorrhage, 4.9%; air emboli, 1.4%; vessel dissection, 4.2%; major groin complications, 2.8%; and emboli to new vascular territories, 0.7%. Rates of symptomatic intracranial bleeding by subtype were PH1, 0.7%; PH2, 0.7% (PH1 indicates hematoma within ischemic field with some mild space-occupying effect but involving ≤30% of the infarcted area; PH2, hematoma within ischemic field with space-occupying effect involving >30% of the infarcted area); intracranial hemorrhage remote from ischemic zone, 0%; intraventricular hemorrhage, 0.7%; and SAH, 3.5%. We did not observe any statistically significant associations of peri-procedural complications with age; type of treatment center; duration of stroke symptoms; NIHSS score, IV thrombolytics, atrial fibrillation, site of vessel occlusion; rescue therapy administered after endovascular treatment; or device. Comparing the Merci with the Solitaire FR retrieval device, we observed symptomatic cerebral hemorrhage (10.9% versus 1.1%; P = .013); symptomatic SAH (7.3% versus 1.1%; P = .07), air emboli (1.8% versus 1.1%; P = 1.0), emboli to new vascular territories (1.8% versus 0%; P = .38), vessel dissection (1.8% versus 4.5%; P = .65), and major groin complications (3.6% versus 7.9%; P = .48). Angiographic vasospasm was common but without clinical sequelae.CONCLUSIONS:Understanding of procedural complications is important for treatment of patients with stroke after endovascular treatment. We observed fewer endovascular complications with the Solitaire FR device treatment compared with Merci device treatment, particularly symptomatic cerebral hemorrhage.

Intravenous tissue plasminogen activator has been proven to be efficacious in recanalization of occluded intracranial vessels and improvement of clinical outcome for acute ischemic stroke.¹ A meta-analysis of 53 studies including 2066 patients with acute stroke demonstrated a 46.2% overall recanalization rate with IV fibrinolysis.^1,2 However, IV tPA has limited ability to open occlusions of medium and large arteries such as the internal carotid artery, proximal middle cerebral artery, or basilar artery, with recanalization rates reported as low as 10%.^2,3 Because of these limitations, catheter-based approaches for acute ischemic stroke have been developed to directly infuse thrombolytics at the site of the thrombus or mechanically extract and disrupt the clot.^3–13 As with systemic thrombolytics, endovascular treatments for acute ischemic stroke carry the risk of intracranial bleeding. These treatments also carry additional risks related to vascular access, catheter placement, direct vessel injury, and the type of device deployed.The Solitaire FR With Intention for Thrombectomy (SWIFT) trial provides additional information about endovascular approaches for acute stroke and directly compares the Solitaire FR device (Covidien, Irvine, California) with the Merci retrieval device (Stryker Neurovascular, Fremont, California) in a prospective, randomized trial. Results of the primary end point for this study have been reported separately.¹³ Acute stroke trials have consistently highlighted the importance of achieving early reperfusion while keeping procedural complication risks as low as possible. The therapeutic time windows are tight, and gains achieved by flow restoration are easily erased by symptomatic intracranial bleeding caused by procedural complications. The SWIFT trial reports a significant technical advance for mechanical thrombectomy by use of the Solitaire device compared with current technology (Merci retriever); the focus of this report is an in-depth analysis of the major procedural complications of this trial.