Endovascular approaches to acute stroke, part 1: Drugs, devices, and data

Abstract

Despite years of research and pioneering clinical work, stroke remains a massive public health concern. Since 1996, we have lived in the era of US Food and Drug Administration-approved intravenous (i.v.) recombinant tissue plasminogen activator (rtPA). This treatment, despite its promise, continues to exhibit its limitations. Endovascular therapy has several theoretic advantages over i.v. rtPA, including site specificity, longer treatment windows, and higher recanalization rates. In this article, we will review the various pharmacologic strategies for acute stroke treatment, providing both a historic context and the state of the art. The drugs will be classified on the basis of their theoretic rationale for therapy. Next, we will review the various devices and strategies for mechanical revascularization with an aim toward comprehensiveness. These range from wire disruption of thrombus to preclinical trials for novel mechanical solutions. This first installment of this 2-part series will end with an analysis of retrograde reperfusion techniques.

Fig 1.

Schematic illustration of the cerebral vascular bed demonstrates the different reperfusion approaches, some of which remain experimental.

Fig 2.

The Merci retriever. A, Baseline angiogram demonstrates complete occlusion of the right ICA terminus (black arrow). B, Posttreatment angiogram demonstrates complete reperfusion of the right ICA territory after 1 pass of the Merci L6 device. C, Native images demonstrate the Merci retriever (white arrow) and the balloon-guide catheter (inflated balloon, black arrow). D, Thrombus retrieved from the right ICA terminus with the Merci device (black arrow).

Fig 3.

A−C, The Phenox retriever is deployed by withdrawing its microcatheter. The device is then slowly withdrawn under continuous blood aspiration through the guiding catheter.

Fig 4.

The Penumbra System. A, Baseline angiogram demonstrates complete occlusion of the proximal M1 segment left MCA (black arrow). B, Posttreatment angiogram demonstrates near-complete reperfusion of the left MCA territory after thromboaspiration with the Penumbra device. C, The device is available in 3 different sizes aimed to treat different vessel diameters. Thromboaspiration is achieved by connecting the microcatheter (black arrows) to an aspiration pump. The “separator” (white arrows) is then advanced in and out of the microcatheter to “unclog” any obstructive thrombus.

Fig 5.

Balloon angioplasty for treatment of atherosclerotic occlusion. A, Baseline angiogram demonstrates complete occlusion of the midsegment of the basilar artery (black arrow). Note the PICA−anterior inferior cerebellar artery (AICA) collaterals (white arrow) with reconstitution of flow at the distal basilar artery. B, Native image demonstrates an inflated Gateway PTA balloon catheter (Boston Scientific) (white arrow) at the level of the occlusive lesion. C, Posttreatment angiogram demonstrates complete reperfusion of the basilar territory with only mild residual stenosis (black arrow).

Fig 6.

Stent placement for treatment of acute intracranial occlusion. A, Baseline angiogram demonstrates complete occlusion at the origin of the superior division of the left MCA (black arrow). B, Posttreatment angiogram demonstrates complete reperfusion of the left MCA superior division territory with only mild residual stenosis (black arrow). C, Native image demonstrates the proximal and distal stent markers (black arrows).

Fig 7.

The NeuroFlo catheter. A, Fluoroscopic images demonstrate the suprarenal (black arrow) and infrarenal (white arrow) balloons. B, Positron-emission tomography demonstrates progressive increase in flow during and after balloon inflation in a patient with a right MCA stroke. Note the global increase in perfusion in both nonischemic (upper panel) and ischemic (lower panel) hemispheres. Courtesy of Professor Wolf-Dieter Heiss, Max Planck Institute for Neurologic Research, Cologne, Germany.