Recently, 5 trials have consistently shown that mechanical thromectomy (MT) improves outcomes in acute ischemia due to proximal occlusion within the anterior circulation. In these trials, rates of intravenous tissue-type plasminogen activator (IV-tPA) were similar among treatment and medical arms thus raising the question whether pre-treatment with IV-tPA is necessary. In this study, the investigators compared clinical outcomes and safety of direct MT alone versus bridging IV-tPA.
This retrospective study is based on a stroke registry that registered stroke patients across a 5 year span. In total, 156 patients were treated with bridging tPA and 239 with direct MT. 40 patients within the latter group had no contraindications to IV-tPA but were opted for direct MT therapy. These patients were matched with patients receiving bridging therapy. Clinical outcomes at three months did not differ between groups; however, there was a trend toward better improvement in the direct MT group. While the rate of symptomatic hemorrhage did not differ, there was higher rates of asymptomatic hemorrhage in the bridging group. Lastly, recanalization and reperfusion rates were similar in both groups.
This study raises an interesting clinical question. Certainly, IV-tPA has been the standard of care for acute ischemic stroke patients. However, in the current new era of endovascular intervention, its role has been questioned in patients who qualify for MT. The majority of patients within the 5 randomized trials did receive IV-tPA per standard practice. Thus, guidelines have recommended to treat with IV-tPA if patients are eligible. tPA can usually be administered quicker and may aid in recanalization. However, recanalization rates of large vessel occlusions are poor and these patients will require MT. IV-tPA treatment in this group, as this study points out, does not improve clinical outcome and may increase rate of hemorrhage. This study was a retrospective study and the number of patients are relatively small. The reason for excluding IV-tPA to the 40 eligible patients is not clear and thus subject to selection bias. tPA may recanalize small vessels particularly within the penumbra and this may be important until recanalization of the proximal occluded artery can be achieved. From a practical standpoint, most hospitals are not endovascular-capable and thus need to transported to a comprehensive stroke center leading to an extensive time difference between tPA administration and MT. Therefore, IV-tPA use should follow current established guidelines. However, future prospective trials should address bridging IV-tPA in combination with MT.
