Background and Purpose Safe and effective anticoagulation plays a pivotal role in neuro-interventional procedures. Patients routinely receive heparin for prevention of intra-procedural thrombosis or thromboembolic complications. We have recently noticed time-dependent variations in intra-procedural thrombosis and thromboembolic complications during our neuro-interventional procedures. Here, we evaluate the effectiveness of our intra-procedural anticoagulation therapy.

Materials and Methods We performed a retrospective case review, comparing the total amount of intravenous heparin administered per case, the peak activated clotting time (ACT) as measured by the i-STAT system, and number of intra-procedural thrombotic complications of 27 consecutive intracranial endovascular neurosurgical procedures requiring intra-procedural anticoagulation from July 1, 2011 through October 15, 2011 (Group 2011) compared to 40 consecutive intracranial endovascular neurosurgical procedures requiring intra-procedural anticoagulation from July 1, 2010 through December 31, 2010 (Group 2010).

Results The mean for total heparin dose given per case for Group 2011 was 12 903 units of heparin, with a SD of 6901, while the mean for total heparin dose given per case for Group 2010 was 8463 units of heparin with a SD of 2484 (p<0.0001, t-test). The peak ACT per case for Group 2011 was 299.2 s with SD of 47.02 compared to the peak ACT per case for Group 2011 was 315.7 with SD of 39.62 (ns). There were a total of six thrombotic complications for Group 2011 vs one thrombotic complication for Group 2011 (p<0.05, Fisher Exact Test). The RR of experiencing a thrombotic complication between the two groups (2010 vs 2011) is 4.266 (95% CI 0.6873 to 26.475).

Discussion and Conclusions When comparing Group 2011 with Group 2010, it took significantly more heparin to maintain similar peak ACT levels and there was a significant increase in the risk of developing a thrombotic complication. These findings are highly suggestive of the decreased effectiveness of intravenous heparin during the dates of July 1, 2011 through October 15, 2011 when compared to a similarly matched group of patients receiving heparin between July 1, 2010 through December 31, 2010. The total heparin dose per case for Group 2011 was not titrated to a predetermined ACT value prior to the start of the endovascular neuro-intervention, but rather a cumulative sum dose of heparin after the end of the procedure. These data give evidence that obtaining an adequate ACT level prior to the start of any endovascular neuro-interventional procedure requiring the use of heparin.

Competing interests None.