SAN DIEGO — While in some respects the jury is still out on the effectiveness of computed tomography (CT) angiography, one physician doing studies in the area of CT for coronary artery disease maintains that he and the physicians who rely primarily on biomarkers "have something in common."
Speaking at the American Association for Clinical Chemistry (AACC; Washington) annual meeting here on Monday, Udo Hoffman, MD, associate professor of radiology at Harvard Medical School (Boston), focused on the integration of imaging, biomarkers and interventional therapy in assessing coronary artery diseases.
The commonality, he said, is that these various measures should result in better diagnosis of the patient. The difficulty, he and other presenters suggested, was how to use them for the various cases seen in the emergency department and what priority to give to each. Hoffman is also co-director of the Cardiac MR, PET CT programs at Massachusetts General Hospital (Boston).
Hoffman noted three types of tools that ED physicians currently use most often to evaluate patients present with chest pains: ECG measurement, cardiac biomarkers in the blood and the patient's history.
But even together these aren't always successful in presenting the correct diagnosis.
Six million people seek help at EDs annually with chest pain, 80% of whom have no acute coronary syndrome (ACS), he said. And Hoffman estimated that 1.5% of missed ACS patients create 20% of ED malpractice cases. And even the patients who are determined to have no ACS cost $8 billion to care for.
So, he said, there is plenty of "room to improve" in the evaluation of patients who arrive in the ED with chest pain.
Discussing the increasing critical role that biomarkers play in assessing such patients was Allan Jaffe, MD, professor of medicine at Mayo Clinic (Rochester, Minnesota).
Jaffe said that "one of the cautions of using" totally anatomical evaluations of chest pain patients is that these will miss some who have heart disease.
Thus, he said that BNP, a cardiac biomarker, has shown "in some circumstances" to have a role in the prognosis for such patients.
But he said that there has been data to suggest the precise "therapy links" between certain biomarkers and the exact therapies to be used.
Addressing the question of what physicians should do once a patient is admitted – and offering differing views of biomarkers vs. imaging — was Kristin Newby, MD, associate professor of medicine at Duke University Medical Center (Durham, North Carolina).
The typical progression of evaluation of a patient with suspected ACS is to use ECGs and then biomarkers to make a diagnosis.
And in terms of these biomarkers, Newby said that "we have moved from CRP [C-reactive protein] to troponin as the gold standard."
She said cardiologists are "blessed with a great deal of studies" but that a distillation of U.S. and European guidelines demonstrates that cardiologists are "very much still driven by what the patient tells us," still another diagnostic tool to be considered.
She said that for patients who appear to be at very low risk by other measurements and history but present with chest pain, this may be the kind of case "where cardiac CT comes in."
Newby contrasted the role and perspective of ED physicians with cardiologists. Cardiologists, she said, "see [patients] at the end of this [ED] process and must decide where they fit into this maze."
At Duke, the medical center attempts to address the thorny problem of diagnosing chest pain in the ED through the development of a Chest Pain Unit, created 10 years ago. The unit is a "separate holding area in the ED" where the patient is held for 10 hours, during that time given three to four batteries of biomarker tests.
"We as cardiologists are interested in whether or not [this is] an imminent or long-term risk patient," she said.
As far as biomarkers, Newby said doctors need to distinguish and be thinking about these tests and how to use them in making distinctions between diagnosis and prognosis. And she said that troponin is "absolutely critical in helping us."
As to the use of CT in the ED, she said that the research is going to have to catch up with technology.
At present, however, she acknowledged that coronary CT imaging "may provide useful information for initial triage decisions."