Effect of Heparin on Recanalization in Acute Stroke Patients with Intra-Arterial Thrombi

Abstract

Anticoagulant use, such as heparin, is usually contraindicated in acute stroke patients. We present a study of patients, who were treated with intravenous heparin after a stroke that were also found to have an intraluminal thrombus. Prior studies imply that recanalization is achieved with heparin; however heparin should only prevent thrombus propagation. Therefore it is unclear whether and how IV heparin can achieve recanalization of intraluminal thrombi in acute stroke patients. A retrospective review of all acute stroke patients from a single stroke center who received a therapeutic IV heparin infusion from 5/2006 to 9/2011 were included in the study. We compared patients who had complete/partial recanalization and/or improved flow versus those that did not, with both these groups on a standard intravenous heparin infusion protocol. Demographic data was compared between the groups. Average partial thromboplastin time (PTT) during heparin infusion, time between computed tomography angiographies (CTAs), time from stroke onset to receiving IV heparin, and vessel occluded were also compared between groups. Forty-one patients (19 female, 22 male) were included in the study with a total of 55 vessels (either carotid, middle cerebral artery, anterior cerebral artery, posterior cerebral artery/posterior circulation) having intraluminal thrombi; 31 patients had 41 vessels with either partial or complete recanalization of effected vessels, while 10 patients had 14 vessels that did not have at least one vessel recanalize while on heparin. Using t-test we noted that the average PTT between the vessels that had partial/complete recanalization group (61.74) and nonrecanalization group (66.30) was not statistical significantly different (P=0.37).The average time in days on heparin between vascular imaging studies (CTA/conventional angiogram) in the group of vessels with partial/complete recanalization (7.12 days) and the ones with no change (6.11 days) was not significantly different between the two groups (P=0.59). Patient's vessels receiving heparin for <24 hours versus those >24 hours did not significantly differ either (P=0.17). This study compares patient characteristics associated with recanalization of intraluminal thrombi in acute stroke patients on heparin. Recanalization of intraluminal thrombi are not associated with average PTT or duration on heparin.

Keywords: Heparin; recanalization; stroke; thrombus.

Figure 1.

Flowchart summarizing the result of the study.