Safety and Efficacy of Fixed-dose Heparin in Carotid Endarterectomy

Safety and Efficacy of Fixed-dose Heparin in Carotid Endarterectomy AbstractOBJECTIVE:Although fixed dosage of heparin is frequently used during vascular surgery, there are very few studies that document the appropriateness of this type of dosing. We have undertaken a prospective study to determine the physiological response to a fixed dose of heparin, using a conventional measure of anticoagulation, and have correlated this measure with complications.METHODS:We studied 140 consecutive patients undergoing elective carotid endarterectomy. Serial activated clotting times (ACT values) were obtained in duplicate before administration of heparin, 15 minutes after application of a carotid artery cross-damp, 0 and 1 hour after administration of 5000 U of heparin by intravenous bolus. Postoperatively, patients were assessed for new neurological deficits (transient ischemic attack and stroke) and neck hematomas. A battery of neuropsychometric tests was ( performed in 49 patients at baseline and on the day after carotid endarterectomy to identify subtle new neurological deficits.RESULTS:ACT values were found to be highly reproducible, with less than a 1.5% difference between duplicate baseline samples. Although all patients received 5000 U of heparin, the dose received per kilogram of body weight varied considerably (44-116 U/kg), as did ACT values at both 15 minutes (178-423 s) and 1 hour (173-390 s). Nevertheless, there was a significant correlation between heparin dose per kilogram and ACT values at 15 minutes (r = 0.45) and at 1 hour (r = 0.38) postinfusion, as well as ACT ratios (final ACT/initial ACT) at 15 minutes (r = 0.43) and at 1 hour (r = 0.34) after heparin 1 bolus. Eight patients (5.7%) developed postoperative wound hematomas, one of which (0.7%) required reoperation. No patient had a stroke, but one patient had a transient ischemic attack, and 19 (39%) of 49 patients demonstrated significant - early postoperative neuropsychometric deficits. Although the incidence of neck hematoma was not influenced by the , heparin dose (P = 0.23), the ACT value at 15 minutes (P = 0.71) or 1 hour (P = 0.61), or the ACT ratio (P = 0.68), the only : severe hematoma requiring reoperation occurred when the maximal ACT value was more than 400 seconds. Although performance on neuropsychometric tests did not appear to be statistically influenced by heparin dosing, the ACT value, or the degree of ACT elevation, there was a trend for deficits to be associated with lower heparin doses.CONCLUSION:Fixed heparin dosing achieves safe and efficacious anticoagulation in the great majority of patients having , carotid endarterectomy, with 5000 U expected to result in 15-minute and 1 -hour ACT values of 175 to 425 seconds and 170 L to 390 seconds, respectively. Although weight-based heparin dosing may reduce the incidence of subtle complications j (hematoma formation or decline on neuropsychometric tests) and may result in more predictable 15-minute and 1 -hour ACT - values (85 U/kg; 225-375 and 200-340 s, respectively), no statistically compelling clinical advantage could be demonstrated' , Therefore, either weight-based or fixed dosing is acceptable, with both obviating the need for routine pre-clamp ACT confirmation, thereby saving operative time and expense. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Neurosurgery Oxford University Press

Safety and Efficacy of Fixed-dose Heparin in Carotid Endarterectomy

Safety and Efficacy of Fixed-dose Heparin in Carotid Endarterectomy Alexander Poisik, M.D., Eric J. Heyer, M.D., Ph.D., Robert A. Solomon, M.D., Donald O. Quest, M.D., David C. Adams, M.D., Catherine Moses Baldasserini, B.A., Donald J. McMahon, M.S., Judy Huang, M.D., Louis J. Kim, B.A., Tanvir F. Choudhri, M.D., E. Sander Connolly, M.D. Departments of Anesthesiology (EJH, DCA, CMB), Neurology (EJH), and Neurosurgery (AP, RAS, DOQ, JH, LJK, TFC, ESC), and Biostatistics Division of the Irving Center for Clinical Research (DJM), Columbia University, New York, New York OBJECTIVE: Although fixed dosage of heparin is frequently used during vascular surgery, there are very few studies that document the appropriateness of this type of dosing. We have undertaken a prospective study to determine the physiological response to a fixed dose of heparin, using a conventional measure of anticoagulation, and have correlated this measure with complications. , METHODS: We studied 140 consecutive patients undergoing elective carotid endarterectomy. Serial activated clotting times (ACT values) were obtained in duplicate before administration of heparin, 15 minutes after application of a carotid artery cross-damp, £ and 1 hour after administration of 5000 U of heparin by intravenous bolus. Postoperatively, patients were assessed for new neurological deficits (transient ischemic attack and stroke) and neck hematomas. A battery of neuropsychometric tests w as ( performed in 49 patients at baseline and on the day after carotid endarterectomy to identify subtle new neurological deficits. RESULTS: ACT values were found to be highly reproducible, with less than a 1.5% difference between duplicate baseline samples. Although all patients received 5000 U of heparin, the dose received per kilogram of body weight varied considerably (44-116 U/kg), as did ACT values at both 15 minutes (178-423 s) and 1 hour (173-390 s). Nevertheless, there was a significant correlation between heparin dose...
Loading next page...
 
/lp/ou_press/safety-and-efficacy-of-fixed-dose-heparin-in-carotid-endarterectomy-spGNpFUDyd
Publisher
Oxford University Press
Copyright
© Published by Oxford University Press.
ISSN
0148-396X
eISSN
1524-4040
D.O.I.
10.1097/00006123-199909000-00003
Publisher site
See Article on Publisher Site

Abstract

AbstractOBJECTIVE:Although fixed dosage of heparin is frequently used during vascular surgery, there are very few studies that document the appropriateness of this type of dosing. We have undertaken a prospective study to determine the physiological response to a fixed dose of heparin, using a conventional measure of anticoagulation, and have correlated this measure with complications.METHODS:We studied 140 consecutive patients undergoing elective carotid endarterectomy. Serial activated clotting times (ACT values) were obtained in duplicate before administration of heparin, 15 minutes after application of a carotid artery cross-damp, 0 and 1 hour after administration of 5000 U of heparin by intravenous bolus. Postoperatively, patients were assessed for new neurological deficits (transient ischemic attack and stroke) and neck hematomas. A battery of neuropsychometric tests was ( performed in 49 patients at baseline and on the day after carotid endarterectomy to identify subtle new neurological deficits.RESULTS:ACT values were found to be highly reproducible, with less than a 1.5% difference between duplicate baseline samples. Although all patients received 5000 U of heparin, the dose received per kilogram of body weight varied considerably (44-116 U/kg), as did ACT values at both 15 minutes (178-423 s) and 1 hour (173-390 s). Nevertheless, there was a significant correlation between heparin dose per kilogram and ACT values at 15 minutes (r = 0.45) and at 1 hour (r = 0.38) postinfusion, as well as ACT ratios (final ACT/initial ACT) at 15 minutes (r = 0.43) and at 1 hour (r = 0.34) after heparin 1 bolus. Eight patients (5.7%) developed postoperative wound hematomas, one of which (0.7%) required reoperation. No patient had a stroke, but one patient had a transient ischemic attack, and 19 (39%) of 49 patients demonstrated significant - early postoperative neuropsychometric deficits. Although the incidence of neck hematoma was not influenced by the , heparin dose (P = 0.23), the ACT value at 15 minutes (P = 0.71) or 1 hour (P = 0.61), or the ACT ratio (P = 0.68), the only : severe hematoma requiring reoperation occurred when the maximal ACT value was more than 400 seconds. Although performance on neuropsychometric tests did not appear to be statistically influenced by heparin dosing, the ACT value, or the degree of ACT elevation, there was a trend for deficits to be associated with lower heparin doses.CONCLUSION:Fixed heparin dosing achieves safe and efficacious anticoagulation in the great majority of patients having , carotid endarterectomy, with 5000 U expected to result in 15-minute and 1 -hour ACT values of 175 to 425 seconds and 170 L to 390 seconds, respectively. Although weight-based heparin dosing may reduce the incidence of subtle complications j (hematoma formation or decline on neuropsychometric tests) and may result in more predictable 15-minute and 1 -hour ACT - values (85 U/kg; 225-375 and 200-340 s, respectively), no statistically compelling clinical advantage could be demonstrated' , Therefore, either weight-based or fixed dosing is acceptable, with both obviating the need for routine pre-clamp ACT confirmation, thereby saving operative time and expense.

Journal

NeurosurgeryOxford University Press

Published: Sep 1, 1999

There are no references for this article.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off