Nuclear cardiology, according to Ronald G. Schwartz, M.D., will continue to play an increasingly important role in the delivery of cost-effective cardiac care as we seek noninvasive cardiology evaluations with optimal diagnostic and prognostic accuracy. The Medical Center's Director of Nuclear Cardiology designed the Nuclear Cardiology laboratory in the Medical Center's new Ambulatory Center. With American Board certifications in internal medicine, cardiovascular disease, nuclear medicine and nuclear cardiology, Dr. Schwartz explains his enthusiasm for the subspecialty's future: "In this era of cost containment, the ability to obtain two quantitative tests of blood flow to the heart and cardiac pumping for the price of one is a value difficult to overlook. Yet that is part of our routine service when we provide combined function and perfusion-gated SPECT imaging."

"No other test is as reassuring to the patient with known or suspected heart trouble as the normal cardiac radionuclide perfusion scan, which can identify the risk of subsequent heart attack or cardiac death as little as 0.3 to 0.5% per year", he explains.

On the other end of the prognostic scale, nuclear cardiology SPECT scanning identifies groups of patients with more than a 20-fold increased risk of subsequent cardiac events.

A second major reason for the continuing growth of nuclear cardiology, Dr. Schwartz explains, is the cost effectiveness of perfusion imaging for assessing acute chest pain in emergency departments and inpatient settings. A single scan following injection of a blood-flow tracer at rest during or shortly after chest pain is highly accurate in detecting ischemic heart disease, and permits rapid, prognostically accurate evaluation in these settings. An added stress test provides substantial long term risk stratification of patients with coronary risk factors.

"With our new facility and with the development of new tracers of blood flow, we are well positioned to take advantage of this approach for rapid evaluation of inpatients and ED patients with chest pain", says Dr. Schwartz. In recent years, Strong Hospital has joined a growing number of leading medical centers in providing an acute cardiac SPECT imaging and consultation service for optimizing the evaluation of patients with chest pain in the Emergency Department. To optimize the care of these patients, utilization of cardiac SPECT, a computerized ECG risk assessment procedure has been implemented at Strong Hospital. "In many patients with cardiac SPECT imaging and the use of short-stay dedicated observations beds in the Emergency Department, we can avoid the time, expense and resource utilization associated with traditional methods detecting heart attack or unstable angina with admission, repeated blood tests and ECG's."

Studies have demonstrated the safety and value of identifying residual ischemia or jeopardized heart muscle within the first few days following heart attack, using the vasodilator "stress" heart scanning. The result: Shorter in-hospital stays for low-risk patients with heart attack.
"Even in the current era of direct angioplasty and use of thrombolytic drugs to treat acute heart attack, a substantial number of patients do not receive these treatments across the country. Even in those who do receive them, we are often unsure which patients have significant residual risk after these treatments are used", says Dr. Schwartz. Cardiac SPECT scanning is an excellent means of identifying risk of further events for this patient group, he says.

Dr. Schwartz has published in the Journal of the American College of Cardiology (August 2003) evidence of the ability of serial cardiac SPECT myocardial perfusion studies to monitor the effectiveness of aggressive medical therapy including statin (cholesterol lowering) medications which are given to reduce the risk of heart attack and death. A recent paper published by Dr. Schwartz and the American Society of Nuclear Cardiology (August 2005) the ability of radionuclide perfusion imaging to identify preclinical coronary disease and its response to therapy.

How Cardiac Imaging with SPECT Is Done
The heart of the new nuclear cardiology laboratory is a system that combines technetium-99 sestamibi with a high-performance multi-head gamma camera, enabling the team to assess simultaneously both cardiac function and regional cardiac blood flow.

For the test, very small doses of radioactive tracer are injected into the patient's arm vein. The gamma camera can detect the tracer as it passes through the heart chambers, during the blood pool phase, after it has been delivered through the coronary arteries to the cardiac muscle. A vivid color picture of the heart at work (or at rest) appears on the computer screen linked to the gamma camera. Computerized analyses of regional heart function and blood flow are clearly displayed as color-coded maps. Continuous movies of the heart in motion reflect the accurate statistical average of hundreds of heart beats, pictures that reveal which areas of heart muscle and coronary arteries are healthy and which are damaged or at risk. If a patient is unable to exercise, cardiac stress is induced with medications. The system also provides rapid analysis of heart pump function by analyzing the blood tracer activity in the pools of blood within the heart chambers and by quantifying the percentage of blood pumped from them.

Acute Cardiac SPECT Imaging for Emergency Chest Pain Triage
As part of Strong Memorial Hospital's chest pain evaluation protocol, Dr. Schwartz and the nuclear cardiology laboratory provide timely evaluations of patients with ongoing or recent chest pain. The sensitivity and availability of this test make it an excellent and efficient method of diagnosing whether chest pain is of cardiac origin and assess the associated risk of heart attack or death. The availability of this service provides a more definitive answer for the patient and referring physician as to whether the pain is likely of cardiac origin and whether patients require immediate admission for treatment. "By providing highly accurate prognostic and diagnostic information in the Emergency Department for proper triage and management of each patient, studies are showing cardiac SPECT scanning is the best and most cost effective way of evaluating these patients," said Dr. Schwartz.

Rapid Report Generation
To date, Dr. Schwartz has compiled approximately 25,000 case studies, which are computerized on an extremely rapid information system he developed for use at the Medical Center, the Nuclear Cardiology Database System (NCDS). This system links to other existing clinical databases that have in more recent years been developed for the rapid dissemination of the reported information to authorized health care personnel.

Training Facilities
Nuclear Cardiology has 2 GE DST Gamma Cameras located in the Paul N. Yu Heart Center and 1 GE DST Gamma Camera at the Clinton Crossings Outpatient Facility.

Annual/Monthly Volumes of Patients/Procedures, etc.

Between the two nuclear labs we are doing approximately 3500 patient studies per year, mostly cardiac SPECT studies. We continue to perform serial radionuclide blood pool ventriculograms ("MUGA" scans) which are extremely accurate and precise for monitoring cardiac performance and help detect and avoid the risk of clinical congestive heart failure in patients receiving cardiotoxic chemotherapy. Dr. Schwartz has published guidelines for the monitoring of cardiac function in adults and children using these serial MUGA scans.

Current and Previous Research Efforts
Current areas of research interest include (1) the detection of preclinical coronary disease in diabetes; (2) monitoring effects of medical and lifestyle therapies to reduce cardiovascular risk; (3) assessing optimal gender-based nuclear cardiology risk assessment methods.

last update 8/24/05/rgsmd