American Association for Clinical Chemistry
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What’s the Evidence on Cardiac Biomarkers?

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What’s the Evidence on Cardiac Biomarkers?
Sessions Highlight Clinical, Analytical Challenges
By Genna Rollins

Existing and emerging biomarkers of cardiac and cardiovascular disease will be the focus of numerous sessions this week, reflecting both the significant disease burden of these conditions as well as the rapidly evolving state of discovery in the field. The programs will explore clinical and analytical issues related to existing cardiac biomarkers, while also examining emerging biomarkers that may improve diagnosis, risk stratification, and treatment of cardiac diseases.

Steady advances over the past two decades have lead to improved diagnosis, treatment and risk stratification of coronary artery disease and heart failure, but challenges remain for physicians and laboratorians in incorporating analytic and clinical evidence into every day practice. “What is the Evidence for Utilization of Cardiac Markers?” will be the subject of a full-day symposium on Tuesday from 10:30 a.m. to 5:30 p.m. in room S102 of the McCormick Place Convention Center. A major emphasis of the program will be the evidence surrounding biomarkers with established roles in coronary artery disease and heart failure-related treatment and diagnosis, including cardiac troponin (cTn) and the B-type natriuretic peptides (BNP and NT-proBNP). In addition, the symposium will address emerging cardiac biomarkers, with discussions about evidentiary benchmarks for assessing these new tools and an analysis of whether emerging biomarkers add to the risk prediction value of the Framingham Risk Score.

“We hope people will walk away with an understanding of the evidence for various cardiac biomarkers and the way we use them,” said symposium moderator, Robert Christenson, PhD, professor of pathology and medical and research technology at the University of Maryland School of Medicine in Baltimore. “It’s important to look at the evidence and understand the difference between expert consensus and real outcomes studies that demonstrate that a test is effective.”

Another part of the symposium will involve a review of the evidence for implementation of the Universal Definition of Myocardial Infarction, which calls for a cTn measurement exceeding the 99th percentile of a normal reference population with a CV ≤10% as an element of diagnosing MI. BNP and NT-proBNP also will be examined, with presentations about the evidence for the biomarkers’ use in risk assessment in the elderly and their effectiveness in facilitating echocardiography triage.

Session Descriptions

  • Brown Bag Sessions
    Limited to 10 participants per session. Ticket required.
  • Chair’s Invited Session
    Open to all conference registrants.
  • Interactive Workshops
    Attendance is limited. Ticket required.
  • Meet the Expert
    Open to all conference registrants.
  • Plenary Sessions
    Open to all conference registrants.
  • Poster Sessions
    Open to all conference registrants.
  • Short Courses
    Attendance is limited. Ticket required.
  • Symposia
    Open to all conference registrants.

Two Perspectives: The Laboratorian and the Clinician

Analytical and clinical issues related to acute coronary syndrome (ACS) and heart failure will be the focus of a morning short course* taking place on Wednesday from 10:30 a.m. to 12:00 p.m. in room S401A of the McCormick Place Convention Center. Although cTn has been the preferred biomarker for diagnosing MI and for risk stratification of ACS for nearly a decade, the diagnostic cutoffs and CVs for the marker have changed over time, in concert with continual analytic improvements in cTn assays. Now a new generation of high sensitivity assays are coming into use, leaving clinicians in somewhat of a quandary about how best to utilize the tests. “Biomarkers for Detection of MI and Risk Stratification in ACS and Heart Failure: Perspectives from a Laboratorian and Clinician” will seek to clarify the changing analytical performance of the assays and the resulting challenges for both laboratorians and clinicians.

“We’ll be talking about the new high sensitivity cTn assays and the impact they will have on establishing really good reference ranges, and their ability to detect small changes from normal in a precise way,” explained Fred Apple, PhD, professor of laboratory medicine at the University of Minnesota School of Medicine, and medical director of clinical laboratories at Hennepin County Medical Center in Minneapolis. “We’ll be looking at both the analytical and clinical implications around these improved assays, and how they will help better manage patients in the emergency setting, triage them to an appropriate level of care, and predict outcomes in a more efficient way.” Apple will provide the laboratorian prospective while Allan Jaffe, MD, professor of medicine and laboratory medicine at the Mayo Clinic, will give the clinician’s side.

The session also will cover novel biomarkers such as myeloperoxidase, mid-regional pro-ANP, and copeptin, which may complement the roles of cTn and BNP in ACS and heart failure, respectively. “We’ll be providing insight as to where the field is going with some idea as to what problems and solutions might be in a dynamic area that’s continually changing,” noted Jaffe.

On Thursday from 9:30 a.m. to 12:00 p.m., Apple and Jaffe will join forces with Robert Schwartz, MD, a cardiologist at the Minneapolis Heart Institute, to explain how the fields of radiology, laboratory medicine and cardiology are collaborating in new ways to improve diagnosis and outcomes in coronary artery disease. The morning symposium “Coronary Artery Disease Update: Integration of Imaging, Biomarkers and Interventional Therapy for Improving Patient Diagnosis and Outcomes” will take place in Room S102 of the McCormick Place Convention Center.

“There’s a sense often when new technologies are developed that they’re going to replace what’s already being used, and that they’re competing,” said Jaffe. “We’ll be exploring how these techniques can be used synergistically, and in that way have more potential for the best interest of patients. So we’ll try and look towards synergism between the fields of cardiology, laboratory medicine and radiology in anticipation of what is likely to develop.”

Analytical Challenges

Analytical issues related to cardiac biomarkers will be the focus of several brown bag sessions*. Mary M. Kimberly, PhD, chief of the Lipid Reference Laboratory at the Centers for Disease Control and Prevention (CDC) will present two brown bag sessions on progress towards standardizing high-sensitivity C-reactive protein (hs-CRP) assays. These ticketed events are scheduled for today; the first, 42114, will take place in Room N229 of the McCormick Place Convention Center from 7:30 a.m. to 8:30 a.m.; the second, 52214, will be held in Room N230AB from 12:30 p.m. to 1:30 p.m.

There are about 30 CRP assays available world-wide today, and the newer generation tests use automated immunoturbidimetric and immunoluminometric methods. Research has shown there are a number of issues related to the assays’ analytical variability, such as varying detection limits, imprecision, and antigen excess. Another challenge for laboratories is assay standardization. However, CDC has an interest in developing a standardization program for hs-CRP assays, and Kimberly will be reporting on efforts she has been spearheading in that regard.

In a separate pair of brown bag sessions* on Tuesday, Kimberly also will review efforts to develop reference systems that will assist manufacturers and clinical labs in establishing measurement traceability for cardiac biomarkers. Session 43112 will take place from 7:30 a.m. to 8:30 a.m. in Room N229 of the McCormick Place Convention Center, while session 53212 will be held in Room N230AB from 12:30 p.m. to 1:30 p.m. “I’ll be discussing the status of developing reference systems for traditional and emerging biomarkers of cardiovascular risk, and reviewing how we use reference systems to establish traceability and accuracy of assays,” she explained.

A third pair of brown bag sessions*, also being held on Tuesday, will focus on analytical requirements for hs-CRP assays, with an eye on evaluating the various assay methods. Session 43109 will take place from 7:30 a.m. to 8:30 a.m. in Room N229 of the McCormick Place Convention Center, and session 53209 will be held in Room N230AB from 12:30 p.m. to 1:30 p.m. William Roberts, MD, PhD, professor of pathology at the University of Utah School of Medicine in Salt Lake City, will present both sessions.

Cholesterol and More

CRP will be part of a broader discussion on lipoproteins that will take place on Wednesday. The full day chair’s invited session, 64301, “Beyond Lipids–Lipoproteins and Inflammatory Markers for Cardiovascular Risk Assessment,” will be held from 10:30 a.m. to 5:00 p.m. in Rooms N229 and N230AB of the McCormick Place Convention Center. “One of the themes of the session is that high density lipoprotein (HDL) is very complicated. It’s actually a family of particles that carry more than cholesterol,” explained Alan Remaley, MD, PhD, section chief of the Lipoprotein Metabolism Section of the Pulmonary and Vascular Medicine Branch at the National Institutes of Health. “The other side of the issue is that the parameters we’re using today to measure cholesterol are perhaps overly simplistic and don’t capture both the good side of HDL and the bad side of low density lipoprotein.”

Remaley and four colleagues will review the latest evidence about the function of apolipoprotein, the main protein in HDL, as well as other lipoproteins that have been identified recently and are under investigation. “There will be a bit of reiteration of what people already know, but the main focus will be on the future of improving cardiovascular risk markers. Our hope is that as we understand more about the biology of lipoproteins, we’ll be able to design new tests that will be better markers for predicting risk,” he added. The session is being moderated by James Wesenberg, PhD, regional medical director-laboratory services for the David Thompson Health Region in Red Deer, Alberta. Wesenberg is the chair of this 2009 annual meeting.

Take Home Message

Laboratorians have a pivotal role in proper selection and interpretation of available cardiac biomarkers and in keeping abreast of the evolving evidentiary landscape. With the many educational opportunities this week, attendees will have be able to focus on the areas of active debate and take home valuable information on cost-effective management of ACS, heart failure and other cardiac diseases, along with practical strategies for implementing and using cardiac-related assays in the clinical setting.

*These sessions require tickets. To check on availability, visit Conference Registration.