Long-term outcome after intravenous thrombolysis of basilar artery occlusion

Occlusion of the basilar artery (BAO) is a relatively infrequent but the most catastrophic form of ischemic stroke with a dismal natural course, carrying from 85 to almost 95 % mortality.

Complete BAO precipitates a sudden or gradually worsening clinical syndrome with bilateral motor weaknesses, visual or speech disturbances, deficits in motor coordination and balance, and often leads to reduced consciousness. The most devastating end-point is the locked-in state, in which the patient is conscious but can move only his or her eyes. Many stroke centers have in the past used invasive, intra-arterial thrombolysis to recanalize BAO, which is limited to hospitals with immediate invasive radiologist service.

Previous reports have advocated thrombolytics delivered with invasive endovascular approach to the occlusion site, but even a short delay in the onset of therapy has been reported to be the single most critical factor affecting outcome. Due to unacceptable treatment delays, Finnish neurologists led by Docent Perttu J. Lindsberg and Professor Markku Kaste at Helsinki University Central Hospital reverted from intra-arterial approach to noninvasive, intravenous delivery of alteplase, a protocol used more commonly in anterior circulation strokes. The results of this study were published 20.10.2004 in JAMA (Journal of American Medical Association).

Since 1995, 50 patients with proven BAO were treated in Helsinki according to institutional thrombolysis protocol. By 3 months, 20 patients (40%) died, while 12 patients (24%) reached independence in activities of daily life. On the long-term, patients with recanalized basilar artery and fair outcome continued to improve functionally and survivors reported unexpectedly satisfactory ratings of the quality of their daily life.

Rates of survival, recanalization and independent functional outcome are at least equally good than reported with endovascular invasive approaches, but the benefits of intravenous therapy are that it can start thrombolysis faster and can be used more widely than the invasive approaches.