Public Release: 

Novel use of radiotracer reveals extent of mycoardial infarction damage

Society of Nuclear Medicine

Los Angeles, California...Investigators reporting at the 49th Annual Meeting of the Society of Nuclear Medicine (SNM) have determined that a noninvasive nuclear medicine technique can accurately and safely detect the extent of persistent heart muscle damage after a heart attack. In two studies, researchers reported on the safety and efficacy 201Tl/99mTc Annexin (ApomateTM) SPECT in detecting and localizing myocardial tissue damage and revealing areas of persistent cellular injury. SPECT (single-photon emission computed tomography) is a nuclear medicine procedure that uses the injection of a radiotracer to produce three-dimensional computer-reconstructed images that reveal information about both structure and function.

In one study, Neil Steinmetz, MD, and colleagues from eight medical centers in the U.S. and Canada reported on the use of 201Tl/99mTc Annexin SPECT in 59 patients who had experienced a myocardial infarction (MI) within the previous 96 hours. 81% of these patients showed persistent myocardial tissue injury on imaging. Even in patients who had been successfully revascularized (blood flowing normally to the heart), the 201Tl/99mTc Annexin SPECT revealed areas of persistent cellular damage. In a second study, Raymond Taillefer, MD, and colleagues from the Centre Hospitalier de l'Université de Montréal (Canada), provided additional evidence that this imaging procedure is effective during the first 4 days after an MI.

Apomate (Theseus Imaging, Boston, MA) is a radiopharmaceutical originally developed for imaging cell death (apoptosis and necrosis) as an early indicator of response to anticancer treatment. The studies reported at the SNM meeting are part of a larger effort to use Apomate and nuclear medicine techniques to determine the extent and location of myocardial cellular injury after an infarction and the response to treatment. Evidence presented at the SNM meeting suggests that Annexin SPECT is safe and effective in detecting persistent areas of damage and diagnosing the extent of past myocardial injury in patients who have experienced MIs. Using this information, physicians may be able to tailor treatment plans and lifestyle changes to the specific needs of each patient Myocardial infarction is the medical term for a heart attack and results when the supply of oxygen is cut off to some portion of the heart muscle. The American Heart Association estimates that more than a million Americans will experience a heart attack in 2002, and more than 300,000 American will die of sudden cardiac arrest.

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The Society of Nuclear Medicine Annual Meeting is being held June 15-19 at the Los Angeles Convention Center, Los Angeles, CA. In addition to educational sessions, the meeting will focus on leading medical developments in the field of nuclear medicine, including radioimmunotherapy with a new class of drugs that target cancer, diagnostic breakthroughs with PET, and other topics. More than 5,000 specialists in the field of nuclear medicine, including scientists, technologists, researchers, and representatives from the medical industry, are expected to attend. The Society of Nuclear Medicine is an international scientific and professional organization with more than 13,000 members dedicated to promoting the science, technology, and practical applications of nuclear medicine. The SNM is based in Reston, VA.

For late-breaking news about the world of nuclear medicine and events at the 49th Annual Society of Nuclear Medicine meeting, visit www.snm.org

Abstract 11. Sunday, June 16, 3:06-3:18 p.m. Room 410
Simultaneous Dual Isotope 201Tl/99mTc-Annexin (ApomateTM) SPECT in Detection of Acute Myocardial Infarction: Initial Results of a Phase II Multicenter
N. Steinmetz, R. Taillefer, R. C. Hendel, F. L. Weiland, D.S. Berman, M.I. Travin, M. Fish, M.E. Mallett, and A.M. Green Main contact:
Neil Steinmetz MD

Abstract 15. Sunday, June 16, 4:15-4:27 p.m. Room 410
99mTc-Annexin V Scintigraphy in Detection of Acute Myocardial Infarction (MI): Repeat Imaging After the Onset of Acute Symptoms in Order to Evaluate the Persistence of Abnormal Radiotracer Uptake
R. Taillefer, D.C. Phaneuf, D.H. Duong, C. Benjamin, S. Lajeunesse, A. Gagnon, A.M. Green, N.D. Steinmetz
Contact author: R. Taillefer
Centre Hospitalier de l'Université de Montréal
Montréal, PQ, Canada

Email: micheline.lauzon.chum@ssss.gouv.qc.ca

Abstract No. 11
SIMULTANEOUS DUAL ISOTOPE 201TL/99MTC-ANNEXIN (APOMATETM) SPECT IN DETECTION OF ACUTE MYOCARDIAL INFARCTION: INITIAL RESULTS OF A PHASE II MULTICENTERN.
Steinmetz*, R. Taillefer, R. C. Hendel, F. L. Weiland, D. S. Berman, M. I. Travin, M. Fish, M. E. Mallett, A. M. Green, Theseus Imaging Corporation, Boston, MA; Hotel Dieu du CHUM, Montréal, Canada; Rush Prebyterian St. Luke's Medical Center, Chicago, IL; Sutter-Roseville Medical Center, Roseville, CA; Cedars-Sinai Medical Center, Los Angeles, CA; Montefiore Medical Center, New York, NY; Sacred Heart Medical Center, Eugene, OR. (202130)
Objective: To evaluate the safety of 99mTc-Annexin V (ApomateTM, Theseus Imaging, Boston, MA) in patients with acute myocardial infarction (AMI) and the efficacy of 99mTc-Annexin V SPECT in detection and localization of AMI.
Methods: 59 clinically stable patients (51 M, 8 F) ages 28-87 (mean 60) with AMI (40/59, 68% reperfused) documented by chest pain, ECG, and enzyme/troponin elevation received Apomate (15-30 mCi, 0.5-1.0 mg Annexin) within 96 hours of onset of symptoms. "Apomate only" (AO) cardiac SPECT images were acquired 4-6 hrs later followed by rest injection of 2-4 mCi 201Tl and simultaneous "single-spin/dual isotope" (SSDI) SPECT imaging with batch mode reconstruction of "Apomate™ dual" (AD) images using the 201Tl images for anatomic reference. Investigators assessed and graded myocardial Apomate™ uptake and 201Tl defects using a 17 segment model of the LV and 5-point scales. Sum of segment scores (SSS) were obtained.
Results: Apomate™ was well tolerated. No adverse events likely to be attributable to Apomate were observed. Overall, 81% of patients showed abnormal Apomate™ uptake suggesting persisting myocardial tissue injury and 90% showed 201Tl perfusion defects. Abnormal Apomate™ uptake was seen in 34 of 40 reperfused patients (85%) and 13 of 18 of nonreperfused patients (72%). Of patients with anterior MI, 13 of 14 (93%), 12 of whom were reperfused, showed abnormal Apomate™ uptake. AO images (mean SSS 28.4) and AD images (mean SSS 28.0) were clinically equivalent.
Conclusion: Apomate™ can be administered safely in patients with AMI. Overall sensitivity of SSDI 201Tl/ 99mTc Apomate™ SPECT images in identification of myocardial injury in patients with AMI is 81%. Apomate™ localizes in both reperfused and nonreperfused infarcts. Even after successful revascularization, Apomate™ images show regions of persisting cellular injury. Separate AO SPECT is not required in patients undergoing SSDI AD SPECT. Comparison of SSS for Apomate™ and 201Tl SPECT permits semi-quantitative assessment; a quantitative myocardial Apomate™ uptake index is under development.

Abstract No. 15
99mTc-ANNEXIN V SCINTIGRAPHY IN DETECTION OF ACUTE MYOCARDIAL INFARCTION (MI): REPEAT IMAGING AFTER THE ONSET OF ACUTE SYMPTOMS IN ORDER TO EVALUATE THE PERSISTENCE OF ABNORMAL RADIOTRACER UPTAKE.
R. Taillefer*, D. C. Phaneuf, D. H. Duong, C. Benjamin, S. Lajeunesse, A. Gagnon, A. M. Green, N. D. Steinmetz, Centre Hospitalier de l'Université de Montréal, Montréal, PQ, Canada; Theseus Imaging Corporation, Boston, MA. (200737)
Objective: 99mTc-Annexin V (ApomateTM, Theseus Imaging,Boston, MA) images obtained shortly after acute MI have demonstrated focal increased uptake in the injured myocardium. The purpose of the study was to evaluate how long this injury signal persists in order to assess the ability of 99mTc-Annexin V (TcAn) to distinguish acute from old MI.
Methods: Sixteen clinically stable patients with a recent MI documented by ECG changes and/or enzyme/troponin changes received an initial injection of TcAn (20-30 mCi, 0.5-1.0 mg Annexin) within 96 hours of onset of symptoms and a second injection of TcAn 9-20 days later. A subgroup of 5 patients who had a persistent focal myocardial uptake on the second TcAn imaging received a third TcAn injection, 50-110 days later. Patients were imaged 4-6 hours following each injection using dual radionuclide cardiac SPECT imaging (with 3-4 mCi of 201Tl). Patients with recurrent chest pain and/or other intercurrent acute cardiac events were excluded. All TcAn images were interpreted by a blinded observer. Myocardial uptake was graded using a 5-point scale (1 = no uptake, 5 = uptake markedly above background). Simultaneous 201Tl images were used as an anatomical reference to localize abnormal TcAn uptake.
Results: On the initial TcAn imaging, all studies (16/16, 100%) showed a significant abnormal localized increase in myocardial uptake of TcAn (grade 3 or more). On the second TcAn study, 5 cases (31%) showed no myocardial uptake (normal study), 8 (50%) showed an uptake but decreased compared the initial study and 3 (19%) showed no change (uptake similar to that seen on the first TcAn study). Out of the 5 patients who had a third injection, 3 (60%) no longer showed uptake, 1 (20%) showed some uptake but less than initially and 1 (20%) showed persistent uptake similar to the previous studies.
Conclusion: 99mTc-Annexin myocardial images performed within 96 hours of onset of acute symptoms can be used to accurately detect acute MI. Although increased uptake persists for 1-3 weeks, it gradually decreases over the subsequent 2-4 months

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