Abstract TP70: Safety of IV tPA Administration with CT Evidence of Prior Infarction

Abstract

Background: Prior stroke within 3 months excludes patients from thrombolysis, however patients may have CT evidence of prior infarct often of unknown time of origin. We aimed to determine if the presence of a previous infarct on pre-treatment head CT is a predictor of hemorrhagic complications following administration of IV tPA. Methods: We retrospectively analyzed the database of consecutive patients treated with IV tPA at our institution from 2009-2011. Pre-treatment CTs were reviewed without knowledge of subsequent hemorrhagic transformation (HT) for evidence of any prior infarct. Further independent review determined if any HT was present on repeat CT or MRI. Symptomatic ICH (sICH) was defined as the presence of parenchymal hematoma (PH-1 or PH-2) and neurological deterioration by ≥ 4 points within 36 hours. Results: Of 212 IV tPA treated patients, 72 (34%) had evidence of prior infarct on pre-treatment CT. Any HT was found in 16%, sICH occurred in 2.4% of the total population, and both events never occurred in the areas of prior infarcts. Patients with prior infarcts on CT were older (median age 72 vs 65; p=0.001), were more likely to have a history of hypertension (85% vs 71%; p=0.024), were on antiplatelet agents prior to admission (49% vs 31%; p=0.007) and had higher pre-treatment NIHSS scores (median 10 vs 7; p=0.023). Patients with prior infarcts on CT did not experience more HT (p=0.3956) nor sICH (p=0.2207), even after stratifying for prior lacunar or cortical stroke appearances (p=0.301). More patients with prior infarcts on CT had microbleeds on follow-up MRI (25% vs 11%; p=0.033), and patients with prior infarcts and microbleeds experienced more HT (63% vs. 10%; p<0.0001) but did not have more sICH (p=0.4784). Conclusions: Visualization of prior infarcts on pre-treatment CT does not predict an increased risk of sICH and should not be viewed as a contraindication for systemic tPA treatment after clinically evident strokes within 3 months were excluded. A subgroup of patients with prior infarcts and subsequently discovered cerebral microbleeds show a propensity to develop asymptomatic HT.