Published Online
on September 16, 2004

A more recent version of this article appeared on November 1, 2004

This Article Full Text (PDF) All Versions of this Article: 35/11_suppl_1/2722    most recent 01.STR.0000143321.37482.b3v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Alexandrov, A. V. Search for Related Content PubMed PubMed Citation Articles by Alexandrov, A. V. Related Collections Acute coronary syndromes

Submitted on June 9, 2004
Accepted on August 5, 2004

Ultrasound Identification and Lysis of Clots

Andrei V. Alexandrov MD^*

From the Department of Neurology and Radiology, Cerebrovascular Ultrasound and Center for Noninvasive Brain Perfusion Studies, Stroke Treatment Team, The University of Texas-Houston Medical School, Houston, Texas.

^* To whom correspondence should be addressed. E-mail: avalexandrov{at}att.net.

Abstract--Poor recovery after systemic tissue plasminogen activator (tPA) therapy could result from the initial severity of ischemic insult and slow and incomplete thrombolysis. Persisting arterial occlusions can be identified at bedside using portable diagnostic ultrasound by detecting residual flow signals around the thrombus (thrombolysis in brain ischemia [TIBI] flow grades). A narrow pulsed ultrasound beam can be steadily aimed at the thrombus/residual flow interface, exposing more thrombus surface and structures to tPA, and tPA activity can be enhanced with 2 MHz transcranial Doppler (TCD). A randomized, multicenter, clinical trial called CLOTBUST (Combined Lysis of Thrombus in Brain ischemia using transcranial Ultrasound and Systemic tPA) trial showed a 49% rate of complete recanalization or dramatic clinical recovery from stroke within 2 hours after tPA bolus when tPA infusion was continuously monitored with TCD, compared with 30% among patients who received tPA without ultrasound monitoring (P=0.03, number needed to treat, 5). Early complete recanalization was sustained at 2 hours by 38% of monitored patients compared with 12.7% controls. The CLOTBUST Trial showed a trend toward sustaining complete recovery at 3 months (41.5% versus 28%, modified Rankin Scale scores 0 to 1), subject for a pivotal phase III trial. Ultrasound is an inexpensive, noninvasive, real-time monitoring tool to identify nonresponders to systemic tPA and select patients with persisting occlusions for intraarterial interventions. Early brain perfusion augmentation, complete recanalization, and dramatic clinical recovery are feasible goals for ultrasound-enhanced thrombolysis.

Key words: outcomes • stroke • thrombolysis • tissue plasminogen activator • ultrasonography, Doppler, transcranial

This article has been cited by other articles:

				R. E. Latchaw, M. J. Alberts, M. H. Lev, J. J. Connors, R. E. Harbaugh, R. T. Higashida, R. Hobson, C. S. Kidwell, W. J. Koroshetz, V. Mathews, et al. Recommendations for Imaging of Acute Ischemic Stroke: A Scientific Statement From the American Heart Association Stroke, November 1, 2009; 40(11): 3646 - 3678. [Full Text] [PDF]

				M. J. Alberts, R. A. Felberg, L. R. Guterman, S. R. Levine, and for Writing Group 4 Atherosclerotic Peripheral Vascular Disease Symposium II: Stroke Intervention: State of the Art Circulation, December 16, 2008; 118(25): 2845 - 2851. [Full Text] [PDF]

				M. Rubiera, M. Ribo, R. Delgado-Mederos, E. Santamarina, P. Delgado, J. Montaner, J. Alvarez-Sabin, and C. A. Molina Tandem Internal Carotid Artery/Middle Cerebral Artery Occlusion: An Independent Predictor of Poor Outcome After Systemic Thrombolysis Stroke, September 1, 2006; 37(9): 2301 - 2305. [Abstract] [Full Text] [PDF]

				F. Schneider, T. Gerriets, M. Walberer, C. Mueller, R. Rolke, B. M. Eicke, J. Bohl, O. Kempski, M. Kaps, G. Bachmann, et al. Brain Edema and Intracerebral Necrosis Caused by Transcranial Low-Frequency 20-kHz Ultrasound: A Safety Study in Rats Stroke, May 1, 2006; 37(5): 1301 - 1306. [Abstract] [Full Text] [PDF]