Only a third of patients with acute stroke who receive intravenous tissue plasminogen activator (tPA) within 3 h of stroke onset achieve complete recanalization. One reason for a poor response to tPA therapy could be that a tandem occlusion of the cervical internal carotid artery (ICA) and the middle cerebral artery (MCA).OBJECTIVES
To determine clinical and anatomic predictors of poor response to intravenous tPA, and to assess whether response to thrombolysis in patients with a tandem ICA and MCA occlusion differs depending on the location of the MCA clot.DESIGN AND INTERVENTION
This Spanish study included 221 patients (109 men, 112 women; mean age 70.5 ± 11.1 years) with an acute stroke attributable to occlusion of the MCA who received 0.9 mg/kg body weight tPA intravenously within 3 hours of symptom onset. Before treatment, all patients underwent a transcranial Doppler (TCD) examination, which revealed a proximal MCA occlusion in 156 patients (70.6%) and a distal MCA occlusion in 65 patients (29.4%). Forty-four patients (19.9%) had a tandem occlusion of the ICA and MCA; the MCA occlusion was proximal in most of these patients (86.4%). At 2 h after administration of the tPA bolus, recanalization was assessed using TCD. The stroke severity at baseline and 24 h after tPA administration was evaluated with the NIH Stroke Scale, and outcome at 3 months was assessed with the modified Rankin Scale; a favorable outcome was defined as a Rankin score of 2 or higher.OUTCOME MEASURE
The primary end point was outcome at 3 months after administration of tPA.RESULTS
The overall rate of recanalization at 2 h after tPA administration was 63.8%. Patients with a tandem occlusion had a significantly lower reperfusion rate than did patients without a tandem occlusion (40.9% vs 69.5%, P=0.01). A lack of recanalization was significantly associated with stroke severity on admission (P=0.023), a baseline glucose level above 140 mg/dl (P<0.001) and the presence of a tandem occlusion (P<0.001). Logistic regression analysis identified an elevated glucose level (odds ratio 2.84, 95% CI 1.1-7.1) and a tandem occlusion (odds ratio 3.17, 95% CI 1.5-6.5) as independent predictors of a poor response to intravenous tPA. The impact of a tandem occlusion on recanalization depended on the location of the MCA clot. Patients with a proximal MCA occlusion and an ICA thrombus were over 4 times more likely to have a poor response to tPA than were patients with an isolated proximal MCA occlusion (recanalization rates 31.8% vs 66.9%; odds ratio 4.63, 95% CI 1.8-11.9). By contrast, the presence or absence of a tandem occlusion had no impact on recanalization rates in patients with a distal MCA occlusion (66.7% in patients with a distal MCA occlusion plus ICA thrombus vs 71.2% in patients with an isolated distal MCA occlusion; P=0.567).CONCLUSION
Stroke patients with a tandem occlusion of the ICA and the proximal MCA tend to have a poor response to intravenous tPA.