Cleveland Clinic's Cremer on cardiac imaging in cardiovascular oncology
From April 20 to 22 in Rosemont, Illinois, physicians, technologists and healthcare professionals gathered for this year's "Nuclear Cardiology Today: Best Practices for Today, Innovation for Tomorrow" conference from the American Society of Nuclear Cardiology (ASNC) to discuss clinical, technical and practical issues in nuclear cardiology imaging.
In the realm of nuclear cardiology lies the evolving subspecialty of cardiovascular oncology, which was discussed in a session featuring Paul Cremer, MD, who focused on the role of cardiac imaging within the field.
Cremer, a cardiologist at the Cleveland Clinic in Ohio, specializes in complex valvular heart disease, cardiovascular CT and MRI, and nuclear cardiology. He has co-authored more than 30 papers related to cardiovascular imaging.
Cardiovascular oncology
Cardiovascular oncology, as Cremer explained, is no longer a new subspecialty of medical imaging—rather, it’s evolving to cover a broader intersection of patients who have cardiovascular disease (CVD) and those with cancer. For the U.S. alone, this group includes about 40 million people.
Currently, an estimated 20 million Americans have heart disease and another 20 million have cancer. Additionally, 50 percent of all Americans have risk factors for CVD, with two million cancer diagnoses per year in the U.S., according to Cremer. However, survivorship rates are increasing.
"This subspecialty has really emerged because of increased survivorship in both cohorts; in cases where patients with cardiovascular disease live longer and patients with cancer are living longer. Related to that, the cardio-oncology patient can be a cancer survivor who gets cardiovascular disease or vice versa when a cardiovascular disease survivor gets cancer," Cremer said.
Cremer believes that the overlap between these two patient cohorts is growing rapidly for two reasons: the U.S. has an aging population and shared risk factors between both CVD and cancer (physical inactivity, smoking, diabetes, etc.) result in a shared immunoinflammatory process.
"So, where does the cardiac imager fit into all this?" Cremer asked the conference audience.
The role of cardiac imaging
The type of disease—cardiomyopathy, CVD, paracardial disease or vascular disease—and risk factors determine a cardiac imager’s protocol and treatment methods, according to Cremer.
He noted that it's especially important to consider underlying risk factors, including that risk those related to the inflammation of the malignancy of cells or complication of treatment via chemotherapy or radiotherapy.
Cremer presented cases of patients with ischemia, coronary disease, cardiomyopathy and cardiotoxicity, and how the pathogeneses are related to underlying risk factors of cancer.
"What I want to emphasize when these patients with ischemia and cardiomyopathy are they're receiving chemotherapy is the heart rate can increase, they may have differences in blood pressure and hypertension, they may be started on different medications, they may be anemic, they may be dehydrated. All of these things can result in changes left ventricular injection fraction that are not related to the chemo therapy, so it's really important to pay attention to these other variables when you're evaluating these patients," Cremer said.
When thinking about cardiotoxicity in a patient cardiomyopathy, he posed the following questions: What imaging test should be used? What drugs should be of concern? What defines cardiotoxicity? How often should patients be imagined for surveillance?
Cremer's prefers echocardiography to monitor cardiotoxicity in a patient with cardiomyopathy.
"When we do echocardiography, we always do it on the same machine and the same strain package, so you really want to minimize, as much as you can, switching between different modalities," Cremer advised.
MRI is costlier and takes longer to perform than echocardiography, Cremer said. Regardless, he advised that cardiac imagers must know what are the "minimally detective differences." Another imaging option is MUGA (multiple gated acquisition) scan to show a moving image of a patient's heartbeat, a highly reproducible imaging method.
Cardiac imagers must be aware of certain chemotherapy drugs, such as doxorubicin, anthracycline and trastuzumab that can cause high levels cardiotoxicity.
Defining cardiotoxicity
In terms of cardiotoxicity definitions and recommendations for surveillance, Cremer said there is a lot of variation in how cardiotoxicity is defined—and it varies depending on which institutional guidelines are being followed.
For example, cancer guidelines for anthracyclines are discontinued if it's below 45 percent or if there's a 15 percent decline in LVF (left ventricular injection fraction), Cremer explained. The American Society of Echocardiography guidelines, however, vary if a drug is in the process of getting FDA approval.
"So, how often should these CVD and cancer patients be imaged?" Cremer asked.
Despite varying cardiotoxicity guidelines, Cremer recommended patients get a baseline echocardiogram, a repeat echocardiogram during chemotherapy or radiotherapy when given higher doses of drugs, and a routine echocardiogram after the completion of therapy. Imaging frequency can also be determined whether the patients has a normal or abnormal LVF at baseline.
A recent graduate from Dominican University (IL) with a bachelor’s in journalism, Melissa joined TriMed’s Chicago team in 2017 covering all aspects of health imaging. She’s a fan of singing and playing guitar, elephants, a good cup of tea, and her golden retriever Cooper.