Diagnostics & Imaging Week Associate
ATLANTA – As an ever-increasing number of Americans are diagnosed with heart conditions, it has become increasingly important that new heart-specific diagnostic technologies and procedures are developed that are easier and more effective than previous methods of assessment.
Emerging technologies to better diagnose heart disease, the use of more rapid ways of evaluating chest pain and newly updated pre-hospital protocols to quickly diagnose and treat heart attack were discussed at the American College of Cardiology (Bethesda, Maryland) annual scientific sessions here at the World Congress Center on Tuesday, the final day of the event.
In a press presentation, Gilbert Raff, MD, reported on a study in which he and a team of researchers from the William Beaumont Hospital (Royal Oak, Michigan), evaluated the use of Computed Tomographic Angiography (CTA), a quick examination that uses X-rays to track blood flow in the veins and arteries and provide a 3-D image of the heart, to exclude coronary artery disease (CAD) as the cause of acute chest pain.
The trial randomized 200 patients to receive either a CTA or standard of care (SOC), which includes an EKG, serial cardiac enzymes and rest-stress nuclear scanning.
Raff, director of Cardiac MRI and CT research at the hospital, said the team found that the SOC quickly and accurately ruled out significant CAD in about 67% of cases, and CAD was correctly assessed in 91% of the CTA patients.
Additionally, CTA quickly ruled out CAD in most cases, while reducing the total time patients spent in the emergency room by about 45% (6.2 hours vs. 14.1 hours) and lowering total time to cardiac diagnosis (3.3 hours vs. 12 hours). In addition to saving time, CTA was about $300 less expensive per patient ($1,595 vs. $1,784) than standard-of-care procedures. In the study, both the CTA group and the standard-of-care group had similar demographics, risk factors and Thrombolysis in Myocardial Infarction risk scores, a test used to determine a patient's risk of mortality.
"Our study shows that CTA can rapidly and definitively exclude CAD as the cause for acute chest pain," said Raff, lead author of the study. "Immediate use of CTA helps reduce a patient's length of hospital stay and decreases overall cost without putting the patient at increased risk."
In another presentation, Akira Kurata, MD, PhD, of Ehime University School of Medicine (Ehime, Japan), discussed a device called the 2nd Spec 256-Multislice CT scanner, which he termed the "next generation" in CT scanners to assess coronary artery health and cardiac anatomy and function.
The device – which Kurata is helping to develop in conjunction with imaging giant Toshiba (Tokyo) – is designed to non-invasively determine whether significant artery disease is present, completing a whole heart scan in an astounding 1.5 seconds without gating and table movement and incorporating the wider coverage available with a CT scanner.
As a comparison, Kurata noted that the commonly used 64-slice CT scanner takes about 10 seconds to complete a diagnostic heart scan.
"The 2nd Spec 256-Multislice CT seems to be a promising next-generation CT for coronary and cardiac imaging," said Kurata.
Kurata and a team of researchers at Ehime tested the efficacy of the new system on two patients, both of whom had previously experienced heart attacks, and determined they could clearly and effectively evaluate the damage from the patients' past heart attacks.
By injecting a contrast solution into each patient, researchers were able to see 2-D and 3-D images of the heart to assess coronary and cardiac function.
Coronary artery structure was evaluated, as was the function of left ventricle, the primary pumping chamber of the heart. The volume of blood moved during the heart's diastolic and systolic cycles was determined and ejection fraction was obtained.
"We are pleased by the speed of the procedure which allows us to assess patients with just one beat of the heart," Kurata said.
Yet another study looked at the role that advanced care paramedics (ACP) – paramedics who have had advanced cardiac life support training – can play in pre-hospital heart attack management, particularly patients exhibiting symptoms of STelevation myocardial infarction (STEMI), a specific type of heart attack.
While previous studies have overlooked the ACP role in pre-hospital heart attack management, study authors from the University of Ottawa Heart Institute (UOHI; Ottawa) assessed the ability of ACPs to accurately identify the STEMI condition and provide the best treatment by taking patients directly to a specialized cardiac facility, bypassing standard ER protocols.
Presenter and lead author Michel Le May, MD, director of the coronary care unit research group at UOHI, said the results showed that mortality dropped significantly, from about 9% in the control group to less than 2% in the group treated under the STEMI protocol.
ACPs receive training in EKG interpretation to identify the STEMI waveform. They independently evaluated patients and brought 108 potential heart attack patients exhibiting STEMI directly to a primary PCI cardiac facility, bypassing the ER.
Researchers compared these patients to a control group of 225 patients who were brought to the hospital emergency room by ambulance.
For ACP-referred patients, the total time between entering the hospital and undergoing primary PCI was 63 minutes vs. 125 minutes for those control group patients who were also treated with primary PCI. Only 9% of the non-ACP-referred patients received primary PCI whereas 94% of ACP-referred patients received the treatment. None of the ACP-referred patients received thrombolytic therapy, a medication used to thin blood clots, which was the first-line treatment for a majority of non-ACP-referred patients (80%).
"With appropriate training, advanced care paramedics can accurately refer STEMI heart attacks, enabling patients to bypass emergency rooms for diagnosis and head directly to cardiac departments," said Le May, lead study author. "This significantly reduces the amount of time patients spend waiting for treatment after entering the hospital, and, in combination with optimal treatment, significantly lowers mortality rates."