Histopathologic Evaluation of Arterial Wall Response to 5 Neurovascular Mechanical Thrombectomy Devices in a Swine Model

BACKGROUND AND PURPOSE: Five commercial devices are available for mechanical thrombectomy in acute ischemic stroke. This study evaluated and compared the resultant arterial damage from these devices. MATERIALS AND METHODS: Wall damage after 4 wall-contact devices (the Merci retriever, Catch thromboembolectomy system, and Solitaire FR revascularization devices of 4 and 6 mm) and 1 aspiration device (the Penumbra System) was evaluated in the superficial femoral arteries of 20 male swine. Each device was tested with and without intraluminal clot. Twenty control vessels were not subjected to any intervention. Acute histopathologic changes were evaluated. RESULTS: In the device samples, endothelial denudation (72.8 29.4% versus 0.9 +/- 1.9%, P < .0001), medial layer edema (52 +/- 35.9% versus 18.1 +/- 27.8%, P = .004), and mural thrombus (5.3 +/- 14.2% versus 0%, P = .05) were found to a greater extent compared with the control samples. The aspiration device provoked more intimal layer (100 +/- 79.1% versus 58.8 +/- 48.9%, P = .27) and medial layer (75 +/- 35.4% versus 46.3 +/- 34.8%, P = .13) edema than the wall-contact devices. CONCLUSIONS: All devices caused vascular injuries extending into the medial layer. The aspiration device was associated with more intimal and medial layer edema, compared with the wall-contact devices except for the Catch thromboembolectomy system.