Speed of tPA-induced clot lysis predicts DWI lesion evolution in acute stroke.
OBJECTIVE
We sought to evaluate the impact of the speed of recanalization on the evolution of diffusion- weighted imaging (DWI) lesions and outcome in stroke patients treated with tissue-type plasminogen activator (tPA).


METHODS
We evaluated 113 consecutive stroke patients with a middle cerebral artery occlusion who were treated with intravenous tPA. All patients underwent multiparametric magnetic resonance imaging studies, including DWI and perfusion-weighted imaging before and 36 to 48 hours after administration of a tPA bolus. Patients were continuously monitored with transcranial Doppler during the first 2 hours after tPA administration. The pattern of recanalization on transcranial Doppler was defined as sudden (<1 minute), stepwise (1 to 29 minutes), or slow (>30 minutes).


RESULTS
During transcranial Doppler monitoring, 13 (12.3%) patients recanalized suddenly, 32 (30.2%) recanalized in a stepwise manner, and 18 (17%) recanalized slowly. Baseline clinical and imaging parameters were similar among recanalization subgroups. At 36 to 48 hours, DWI lesion growth was significantly (P=0.001) smaller after sudden (3.23+/-10.5 cm(3)) compared with stepwise (24.9+/-37 cm(3)), slow (46.3+/-38 cm(3)), and no (51.7+/-34 cm(3)) recanalization. The slow pattern was associated with greater DWI growth (P=0.003), lesser degree of clinical improvement (P=0.021), worse 3-month outcome (P=0.032), and higher mortality (P=0.003).


CONCLUSIONS
The speed of tPA-induced clot lysis predicts DWI lesion evolution and clinical outcome. Unlike sudden and stepwise patterns, slow recanalization is associated with greater DWI lesion growth and poorer short- and long-term outcomes.
Delgado-Mederos
Raquel
R
Department of Neurology, Hospital Universitari Vall d'Hebron, Universitat Autonoma de Barcelona, Barcelona, Spain.
Rovira
Alex
A
Alvarez-Sabín
José
J
Ribó
Marc
M
Munuera
Josep
J
Rubiera
Marta
M
Santamarina
Esteban
E
Maisterra
Olga
O
Delgado
Pilar
P
Montaner
Joan
J
Molina
Carlos A
CA
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D020521:Stroke / Q000188:drug therapy* / Q000473:pathology; D013927:Thrombosis / Q000188:drug therapy* / Q000473:pathology; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage*; D016896:Treatment Outcome
D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator