Sponsored by an educational grant from Toshiba America Medical Systems
Coronary CT angiography is making its mark on 21st century cardiac medicine. Cardiac imaging pioneers across the globe are demonstrating that dynamic volume CT improves and accelerates patient care and cuts costs by reducing length of stay. It also facilitates diagnosis of subclinical atherosclerosis, allowing cardiologists to prescribe preventive treatment to at-risk patients earlier in the disease process.
One early adopter of state-of-the-art cardiac CT angiography is the Piedmont Heart Institute in Atlanta, Ga. The center deployed Toshiba America Medical Systems Aquilion ONE CT system in October 2008 and is tapping into the new scanner to re-invent the standard of care for patients presenting to the ER with chest pain.
The early results are impressive. Since implementing the Aquilion ONE dynamic volume CTA model, the average hospital stay for a patient presenting to the ER with chest pain has dropped from 14 hours to five hours, which is expected to correlate with reduced costs. Researchers at the institute expect to finalize a formal cost analysis later in 2009. Equally important, Aquilion ONE slashes radiation dose compared to other cardiac imaging modalities including 64-slice CT and nuclear stress studies. A 64-slice CT study at Piedmont exposes the patient to 15 to 25 millisieverts (mSv) of radiation, and a nuclear stress test exposes the patient to a radiation dose of 15 to 28 mSv. On the Aquilion ONE, on the other hand, the radiation dose is between 3 and 6 mSv in most routine patient exams.
Dynamic volume CTA is a winner from all perspectives: clinical, economic and efficiency. This issue, Piedmont Heart Institute shares early outcomes of its coronary CT angiography program with Cardiovascular Business.
The conventional standard of care
Prior to adding dynamic volume cardiac CT, Piedmont Heart Institute relied on nuclear perfusion as the imaging study of choice for patients who presented in the ER with chest pain. Specifically, physicians ordered an EKG and cardiac enzyme tests for patients with no history of coronary disease. Patients whose results did not suggest ischemia were referred to nuclear medicine for a nuclear stress test.
The nuclear stress test poses several challenges. For starters, emergent patients must be worked into the nuclear medicine schedule for the study; however, it’s difficult to work in all patients, particularly those arriving in the late afternoon or evening. “With nuclear studies, the patient is at the mercy of how much isotope is in stock. The department can run out toward the end of the day,” says Szilard Voros, MD, medical director cardiovascular MR and CT. If the hospital can not perform a same-day stress test, the patient is held overnight in an observation unit. Voros estimates that the average chest pain process for negative patients lasts three to six hours with significant variation, particularly for overnight patients.
In addition to presenting operational challenges, nuclear perfusion can be time-consuming and uncomfortable for the patient. It takes three to four hours to complete the entire study, which consists of stress and rest images with each acquisition lasting 10 to 15 minutes.
The new and improved paradigm
As a matter of perspective, each year 8 million Americans visit emergency departments with chest pain symptoms. Although only 5 to 15 percent of these patients are found to be suffering from a heart attack or other cardiac issue, more than half of these patients are admitted to the hospital for observation and further testing. This, ultimately, could lead to additional diagnostic cost without better treatment.
Piedmont Heart Institute developed a new chest pain strategy based on the Aquilion ONE dynamic volume CT scanner. Turnaround time is shorter, fewer patients are kept overnight and costs are lower. A study at the University of Pennsylvania of 568 patients showed the average ED cost of a patient receiving a first-round CTA averages $1,240, while stress testing and telemetry monitoring are more than $4,000 per patient. That means that a patient can have more than