Bridging Therapy with i. v. rtPA in MCA Occlusion Prior to Endovascular Thrombectomy: aDouble-Edged Sword?

Abstract

Recent studies suggested that preinterventional intravenous (i. v.) recombinant tissue plasminogen activator (rtPA) as bridging therapy facilitates successful and fast vessel recanalization in endovascular stroke treatment (EST); however, data on this effect and the associated clinical value are discrepant. This study examined if this discrepancy could be related to an effect-modifying variable, specifically to the exact occlusion site. Retrospective analysis of 239 patients with acute occlusion of the middle cerebral artery (MCA) treated with up to date endovascular techniques. Effects of i. v.-rtPA bridging on clinical outcomes and safety/efficacy of EST, defined as the respective rates of successful, first pass and thrombolysis in cerebral infarction (TICI) scale 3 recanalization, were evaluated and stratified according to distal versus proximal occlusion sites. Overall, i. v.-rtPA bridging was associated with asignificantly higher rate of successful recanalization (86.9 % vs. 75.7 %, p= 0.028). i. v.-rtPA bridging-related effects, however, were observable only in distal, but not in proximal MCA-occlusions. In distal occlusions, i. v.-rtPA clearly favored successful recanalization (adj. OR 4.6, 95 %-CI 1.5-13.6, p= 0.006) and first-pass successes (adj. OR 2.8, 95 %-CI 1.0-7.6, p= 0.042), but tended to be associated with lower rates of complete (TICI-3) reperfusion (adj. OR 0.4, 95 %-CI 0.2-1.1, p= 0.068). The net effect was asmall clinical benefit, reflected in higher rates of strong neurological improvement (adj. OR: 2.8, 95 %-CI: 1.1-6.9, p= 0.03). i. v.-rtPA-bridging-related effects are occlusion site-dependent, paralleling similar effects of systemic i. v.-rtPA when applied without subsequent endovascular therapy. In distal occlusions, i. v.-rtPA facilitates thrombectomy, but may also promote distal embolization, with asmall clinical benefit as overall net effect. Randomized trials assessing i.v-rtPA bridging need to be stratified according to occlusions sites.