Abstract 238: Utilization and Safety of a Heparin Nomogram in Treating Thrombotic Comorbidities in Stroke Patients

INTRODUCTION: AHA guidelines discourage anticoagulation in acute ischemic stroke (AIS) patients to prevent stroke recurrence. However, some AIS patients have concurrent thrombotic states, such as DVT/PE, that require anticoagulation to prevent further morbidity. Little is published on the safety and efficacy of heparin titration nomograms used for thrombotic comorbidities in stroke patients. Our aim was to assess the utilization and safety of a heparin stroke infusion nomogram at a single, tertiary, academic hospital. METHODS: The heparin stroke nomogram contains no heparin bolus, a goal aPTT of 60-85, and stable “steady state” dose with 2 consecutive aPTT values at goal. Patients were identified via a retrospective, computerized order entry review for the heparin nomogram. Exclusion criteria were: baseline aPTT > 50s, a hypercoagulable state, and short usage (< 24 hrs) or interrupted nomogram prior to 2 consecutive “goal” aPTT values. Demographic data and aPTTs were determined from the prospectively-populated enterprise data warehouse. The aPTTs were divided into 6 hr time bins from initiation. Indication and outcomes were determined by source document review by a stroke neurologist. RESULTS: From 1/2010 - 6/2011, a heparin nomogram for any indication was initiated in 2,016 patients with 144 (7%) of these utilizing the “stroke” heparin nomogram, The nomogram was ordered by neurology (72%, n=103 ), neurosurgery (8%, n=11), other surgical specialties (9%, n=13), internal medicine (7%, n=10), and other (5%, n=7). After excluding those as above, the “stroke” heparin nomogram was used in 86 patients (40% female; mean 55 yrs SD 17), 74 with AIS, 2 with ICH, 1 with SAH, 2 with craniectomy, and 3 other. The indication for heparin included large artery near total occlusion (30%, n=26), cardiac thrombus (suspected (26%, n=22) or visualized (9%, n=8)), cerebral sinus venous thrombosis (10%, n=9), DVT/PE (5%, n=4), artery dissection (17%, n=15), and other (7%, n=6). Percent of “at-goal” aPTTs by 6 hr time bins were: 6-12 hrs: 24% (n=21/86); 12-18 hrs: 36% (n=31/ 86); 18-24 hrs: 48% (n=40/84); 24-48 hrs: 55% (n=42/77); 48+ hrs: 65% (n=29/45). At the 42-48 hrs time point, 4% of patients had aPTT>150. There were 4 non-bleeding related deaths. Repeat AIS occurred in 3 patients of the 74 patients with primary AIS. Asymptomatic ICH occurred in 1 patient with primary AIS; symptomatic hemorrhage occurred in 2 patients (epistaxis, GI). Discharge anticoagulation was prescribed in 56 patients (65%). Ninety day readmission occurred in 15% of patients (n=13), 5 for bleeding. CONCLUSION: The heparin stroke nomogram appears safe in that it does not increase risk of ICH. However, therapeutic aPTTs are not reached quickly with less than half of patients therapeutic at 24 hours, nor are they maintained at steady state. This nomogram could be too conservative in cases where clinical situation requires rapid anticoagulation.