NEW YORK As the 16th edition of the Piper Jaffray Health Care Conference concluded here late last month, much of the crowd had already departed, presumably for warmer climes. However, those still in attendance as the three-day gathering drew to a close were treated to an informative panel on the use of and emerging trends in diagnostics in the emergency department and intensive care unit.
Panel moderator Steve Hamill, vice president and senior research analyst covering the diagnostics and blood management and safety sectors for Piper Jaffray (Minneapolis, Minnesota), described the latest push in diagnostic firms' research and development efforts to come up with new markers for key life-threatening conditions "where there is a desperate need for improved diagnostic capabilities, such as stroke, sepsis and coronary syndromes."
He said such new tests would do well to follow the blueprint for other benchmark diagnostic markers such as troponin and B-type natriuretic peptide (BNP), and he gave reasons that he believes those two cardiac markers have been so successful. "First off, both are used on large numbers of presenting patients," Hamill said. Secondly, "both have high degrees of morbidity or mortality in terms of their conditions, particularly, of course, AMI [acute myocardial infarction]." He also pointed out that the symptoms can be misleading in both cases. "Previous diagnostic paradigms were either very poor or very expensive particularly, I think, in the case of heart failure."
Hamill said it is paramount to have a rapid definitive diagnosis in both cases "before you sent that patient on for further treatment, or, perhaps more importantly, before you sent them home, given litigation risk, which is obviously a hot topic in general in healthcare today."
He queried the panel as to the challenges of identifying stroke victims' misleading symptoms and the ramifications of an incorrect diagnosis.
"The most important thing to keep in mind, in terms of stroke treatment today, is what we call the therapeutic window, or the window of time sensitivity for getting the patient into a therapeutic modality, is extraordinarily tight," said Peter Wyer, MD, of Columbia Presbyterian Hospital (New York). He noted that the current guidelines for administration of clot-busting drugs such as tissue plasminogen activator (tPA) for patients who suffer from ischemic stroke require that the drugs be administered within three hours of onset of symptoms, a very narrow window for effective treatment.
Not only that, but the triage in the ED also has to perform a CAT scan in order to determine if the patient is having an ischemic or hemorrhagic stroke, for which thrombolitic therapy would be contraindicated. "If you add that up," he said, "we really only have minutes in which we can make a distinction between patients who look like they might be having a stroke and patients that are." So one of the requirements for an effective stroke test is that it must be able to provide an accurate answer "within minutes." He added that if a test could identify brain cell death, along the lines of what some of the cardiac markers do for myocardial infarction, "that could be extraordinarily helpful."
Steven Davidson, MD, of Maimonides Medical Center (New York), noted that stroke patients "are arriving at the rate of two to four a day in my 80,000 visit-a-year emergency department. So we're trying to sift them out of the 220 patients a day and then build this pathway that can reach diagnosis in 60 minutes and make it operate."
As far as the need for speed in stroke diagnosis, Wyer stressed that patients who suffer such an episode do not generally have the luxury of extra time beyond the three-hour window. "The frontiers of stoke intervention at this point are actually more constrained by time sensitivities, I think, than even coronary episodes."