José G. Merino, MD, MPhil


June 18, 2013

In This Article

Hemorrhagic Transformation After tPA

The greatest risk with thrombolytic treatments is hemorrhagic transformation (HT), and several presentations described ways to identify the patients at highest risk. Ashkan Shoamanesh from Boston and his colleagues[3] did a systematic review of the literature to determine whether the presence of cerebral microbleeds (CMBs) is associated with a risk for HT. They found that in 5 studies with 790 participants, the prevalence of CMBs was 17%. Patients with CMBs were more likely to have HT (odds ratio [OR], 2.3; 95% confidence interval [CI], 1.01-5.17), and the risk was higher in patients with more than 10 CMBs (OR, 12.18; 95% CI, 1.7-88.7). As the investigators pointed out, however, the results do not yet warrant withholding tissue plasminogen activator (tPA) for most patients with CMBs.

Glen Jickling and colleagues[4] compared the leukocyte RNA expression profiles in stroke patients with and without HT after tPA. Blood was collected before tPA was given. Patients who developed HT had different expression of 29 genes involved in inflammatory and coagulation pathways, and a panel of 6 of these genes could predict who developed HT with 86% accuracy.

Recanalization and Reperfusion

Among 527 patients with moderately severe stroke who had endovascular treatment and were enrolled in the Italian Registry of Endovascular Treatment in Acute Stroke, 42.7% had good functional outcomes. As Domenico Inzitari and colleagues reported,[5] complete reperfusion (seen in 52% of the patients) strongly predicted good functional outcome (OR, 1.9, after adjustment for sex, age, baseline National Institutes of Health Stroke Scale [NIHSS] score, time to therapy, site of occlusion, and treatment modality).

Some have argued that patients without vascular occlusion will not benefit from thrombolysis. To examine this hypothesis, Sourabh Lahoti and colleagues[6] from 5 hospitals in the United States, Europe, and India did a retrospective review of patients with acute stroke who did not have vascular occlusion on CTA or MRA and found that 90-day outcomes were similar regardless of whether the patients were treated with intravenous tPA. Because of the retrospective nature of the study, the findings must be interpreted with caution, and a prospective study is warranted before findings on MRA/CTA can be used to select patients for treatment.

Factors other than the nature of the vessel occlusion may determine whether patients benefit from interventional therapies. In an analysis of angiograms in 371 patients enrolled in the Interventional Management of Stroke III study, David Liebeskind and colleagues[7] found that the extent of collaterals was positively associated with recanalization, reperfusion, and long-term clinical outcome.