Cath Lab Digest - January 2008 - (Page 41)

41 Figure 1. The Hemochron (International Technidyne Corp, Edison, NJ). Figure 2. HemoTec (Medtronic HemoTec, Inc., Englewood, CO) received a heparin dose in the emergency room. Generally, patients who come to the cath lab for a diagnostic procedure, such as an outpatient, for example, would not receive an anticoagulant until it was decided that an angioplasty was needed. In these cases, the ACT would not be performed until approximately 10 minutes after the heparin administration. This brings up another debate that I can present, but not resolve. What about the use of bivalirudin (Angiomax, The Medicines Company, Parsippany, NJ) in PCI? There is debate in the literature regarding whether the current ACT systems developed for heparin monitoring can be used to accurately portray the anticoagulation status of patients who have received bivalirudin.2-5 Because of the established performance and reliability of bivalirudin, ACTs are often not needed. However, a common practice is to perform an ACT test on the patient 10 minutes after the administration of bivalirudin. Often, you will get a result of “High” or “Out of Range.” This assures that the IV access was good and that the medication made it into the circulatory system. The cardiologist could then proceed with the case. The debate is AFTER the procedure, whether post-procedure results are accurate and correlate to the true anti-coagulation status. Bivalirudin studies state that the ACT should be low enough to pull the sheath 2 hours after the medication has been stopped. This is due to the half-life of bivalirudin. However, if you have taken care of a patient with a sheath in for longer than 2 hours, and someone performs an ACT, the results can often be higher than 150. In patients with renal failure, the ACT can be substantially higher for a longer period of time. More studies and documentation on this will be required before definitive changes in practice occur. The ACT exam is not without its flaws. Patients can respond differently to heparin administration, to the point that the ACT will be ‘off’ from what is expected. There can be a wide individual variation in results, even with the same sample and the same operator on exactly the same equipment. The ACT is intended as a general guideline and not an exact result. The ACT is influenced by many outside factors, including, but not limited to: temperature of the tube/slide, patient hypothermia, hemodilution, too little/too much sample, etc. An important safety rule: if the patient is administered a loading dose of heparin/bivalirudin, but the ACT fails to show an increase (over 180 seconds) immediately confirm that the dose actually made it into the patient. This could mean checking the IV patency, the IV line and the medication actually administered. Clotting complications can occur if one blindly assumes that the patient is anti-coagulated. If there is ever a doubt on the accuracy of the ACT, perform another test. A result is generally available in less than 5 minutes. The proper analysis of ACT is an important part of any PCI, and helps to assure a basic level of safety for the patient after the administration of potent anti-coagulant medications. ■ References 1. Libby P, Bonow RO, Zipes DP, Mann DL. Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine. 8th Edition. Philadelphia: Elsevier Science 2007, 1-2183. 2. Cheneau E, Canos D, Kuchulakanti PK, et al. Value of monitoring activated clotting time when bivalirudin is used as the sole anticoagulation agent for percutaneous coronary intervention. Am J Cardiol 2004;94:789–792. 3. Lincoff AM. Pilot study of bivalirudin versus heparin during percutaneous coronary intervention with stenting and GP IIb/IIIa blockade:results of the REPLACE 1 trial (abstr). J Am Coll Cardiol 2002;39(suppA). 4. Lincoff AM, Kleiman NS, Kereiakes DJ, et al for the REPLACE-2 Investigators. Longterm efficacy of bivalirudin and provisional glycoprotein IIb/IIIa blockade vs heparin and planned glycoprotein IIb/IIIa blockade during percutaneous coronary revascularization: REPLACE-2 randomized trial. JAMA 2004;292:696-703. 5. Bejarano J, Muniz AJ. Use of bivalirudin instead of heparin during a percutaneous coronary intervention in a patient with severe thrombocytopenia. J Invasive Cardiol 2004 Sept;16(9):535-536. Next month: We will tackle a question concerning the many different ways to calculate cardiac output. http://www.wavemark.net/CLD01 http://www.wavemark.net/CLD01

Table of Contents Feed for the Digital Edition of Cath Lab Digest - January 2008

Cath Lab Digest - January 2008 Central Baptist Hospital Contrast Media Use in High-Risk Patients An Ergonomic Survey of Cath Lab Repetitive Stress Injuries Contents Clinical Editor’s Corner Takotsubo Cardiomyopathy, a.k.a., Transient Left Ventricular Apical Ballooning Syndrome: An Acute Coronary Syndrome Imposter Searching for the Key to D2B STEMI Intervention News STEMI Interventions: Commentary The Massachusetts Stent Study The Value of Educating Staff Ask the Clinical Instructor: A Q&A Column for Those New to the Cath Lab SICP* Chapter Updates The Society of Invasive Cardiovascular Professionals Holds an RCIS Review Course at New Cardiovascular Horizons 18:20 To Denver — One Student’s First Clinical Experience CEU Education Center Meetings Calendar What Do You Think? Clinical & Industry News Classifieds The Ten-Minute Interview with…Heather Vardon, RN Advertisers Index

Cath Lab Digest - January 2008

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