Patient-centered approach to CV imaging can improve care
The evolving field of CV imaging has become more patient-centered, which can lead to better care and improved patient compliance, according to a presentation at the American Society of Nuclear Cardiology Annual Meeting.
Diagnosing stable ischemic heart disease using different imaging modalities has come a long way with a variety of clinical trials, Leslee J. Shaw, PhD, FACC, FASNC, FAHA, professor of medicine in the division of cardiology at Emory University, co-director of Emory Clinical Cardiovascular Research Institute and a member of the Cardiology Today Editorial Board, said during the presentation. Myocardial perfusion imaging currently has numerous class I indications from trials such as COURAGE and BARI 2D. PET prognosis is another tool to look at coronary flow reserve, according to the presentation. Currently, Shaw and colleagues are working on the ISCHEMIA trial, which focuses on the best management strategy for patients with stable ischemic heart disease and will be completed in the next 18 to 24 months.
“This is 2 decades of my life in stable ischemic heart disease,” Shaw said during the presentation. “We have an opportunity to see this growth and evolution in a procedure and how it came to fruition here today in terms of understanding the value of it to clinical management in this large area of stable ischemic heart disease.”
Nuclear cardiology has led to evidentiary standards due to its high prognostic and diagnostic accuracy, which has been validated in clinical trials, according to the presentation. It has also resulted in the decline of CV mortality during the past 10 years.
“That achievement is something that we have to sit back at times and say are we still there? Are we still leaders, or is there more that we can do to set the standard, to set the pace to be the innovators that we are perceived to be,” Shaw said.
Recent data have shown that its effectiveness has declined, potentially due to testing lower-risk patients. Disease prevalence is in the 15% to 20% range, which resulted in a lower occurrence of abnormalities. In the CLARIFY registry, ischemia was not predictive of outcomes, although the registry contained low-risk patients. As the rate of coronary disease declines, patients who are sent to the catherization lab often have nonobstructive disease. Other modalities that are being studied include MR perfusion, CT perfusion and CT-derived fractional flow reserve.
“This is just a call to action,” Shaw said. “This is not a criticism. This is a time for re-evaluation of our patient population and a core of what is the strength of nuclear cardiology.”
CV imaging can also be looked with regards to cost of care and life expectancy. Before, value-added health care was a major focus, which lead to improvements in life expectancy, although that is often not seen in the United States now.
“As a matter of fact, in the United States, our life expectancy is up to 3 years less than a lot of Westernized, developed countries and European countries,” Shaw said. “We spend multifold higher than other countries do on their health care system. We can do a much better job of what we’re doing in cardiovascular imaging.”
Issues in CV imaging and health care can possibly be resolved with innovative solutions, according to the presentation. Shaw said inconsistent quality, widespread waste and unacceptable levels of harm are some of the issues seen in CV health care today, and simplifying health care through disruptive innovation and personalized care can help unify not only CV medicine, but also primary and specialty care.
“We need that imaging to be patient-centered and personalized and tailored to the needs of that patient,” Shaw said.
Strategic priorities also must be considered in addition to innovation to make health care more efficient and effective, according to the presentation. An imaging procedure, regardless of what it is, must benefit the patient more than if they did not undergo it at all, which contributes to a network approach to chronic diseases.
“If you look at all of your patients with chronic diseases, it’s incredible how much overlap and how much interconnectivity you have across the disease states,” Shaw said.
Diseases that are interconnected included chronic lung disease, hypertension and diabetes. Lifestyle factors like pollution, obesity and smoking are also connected both horizontally and vertically with clinical phenotypes, biomarkers and genetic markers. Within one scan, coronary calcium scoring can be calculated in addition to screening for lung cancer and even breast cancer. Through the imaging of calcification, the pool of candidates for coronary calcium imaging has expanded, according to the presentation.
“You have got to start thinking strategically of this so you can optimize referrals and you can create opportunities to broadly engage and to collaborate across primary and specialty care,” Shaw said. “You can actually think more broadly about the conditions that you serve and how other imaging modalities are equally serving those patient populations for whom cardiovascular imaging might also be an opportunity to image and to appropriately grow those indications.”
CV imaging can develop transdisciplinary collaborations, transform the health care system and benefit population health, according to the presentation. Using a triple aim of health care, clinicians can focus on making patients healthier, improve care by avoiding unnecessary procedures and spend smarter to reduce costs. This approach has been supported by CMS and other health care agencies.
The current algorithm to evaluate stable ischemic heart disease is outdated, Shaw said. Although it focuses on the detection of coronary disease, obstructive coronary disease and decision-making around revascularization, it only focuses on a small portion of patients.
“If we talk about population management, we have got to start focusing on evaluation algorithms that meet the needs of patients without obstructive coronary disease,” Shaw said. “We have to meet the needs of people with mild coronary disease, atherosclerosis as well as their imaging needs. We have to redesign to meet the needs of our entire population and not just those with obstructive coronary disease.”
Questioning how different societies look at different modalities leads to innovation, according to the presentation. The U.K.’s National Institute for Health and Care Excellence (NICE) released the NICE guidance document, which eliminated pre-test risk estimate and exercise ECG for initial diagnostic tests due to their reduced accuracy and diagnostic uncertainty. The committee members who wrote the document were predominantly primary care physicians and had one radiologist.
“We can come up with some other innovative approaches, not just CT first,” Shaw said. “I’m not trying to put forth that, but innovation requires listening, evaluating and thinking creatively about the problems that we have today.”
The PROMISE trial had a lot of patients, but did not achieve the risk that they originally predicted. Among 10,000 patients, 12% had coronary disease, which may be due to patients who were too low risk, according to the presentation.
“We have to start thinking about deferring testing in these lower-risk patients and doing selective imaging strategies because the prevalence of disease of 12% means we’re going to spend a lot of money to identify so few patients. What can we do to do a better job of that,” Shaw said.
One approach to lowering costs is coronary calcium scanning, which is $59 with CMS reimbursement, according to the presentation. It can be used for lower-risk patients as an index procedure and can also affect preventive management. Seeing scans can lead to improved patient compliance.
Research is being conducted to locate calcified plaque, the number of lesions in a vessel that are involved and the size of the lesions, which should come out in the next 5 to 8 years.
The WOMENs trial, which Shaw took part in, showed that exercise ECG was as safe and effective as an exercise myocardial perfusion test at a lower cost. Five years later, in the CRESCENT trial, a low-cost evaluation strategy, which included testing for coronary calcium first and those with no score did not undergo further testing, was more effective than an exercise ECG. Patients with no score did not have events at 2 years.
Another test that can be added is myocardial blood flow or coronary flow reserve, which improves risk detection, gives insight into coronary microvascular function and aids in therapeutic risk reduction. Coronary flow reserve can detect both obstructive and nonobstructive coronary disease.
“Now as we think about population management, we’ve grown into focusing not just on obstructive coronary disease, but now in terms of capturing risk in other patient populations with lower disease prevalence,” Shaw said.
Mechanisms that drive myocardial ischemia go beyond obstructive coronary disease and epicardial atherosclerosis, according to the presentation. These two conditions can help detect abnormalities and understand the physiology of them. Understanding the physiology of ischemia, hypertensive disease and cardiomyopathies can help clinicians explain it to the referring physician and potentially present false negatives and positives.
“We have to be more disease-based and more biologically based in order to drive that message,” Shaw said.
The relationship between stenosis and ischemia can vary, as they may occur with or without the other, according to the presentation. Mild to intermediate stenosis can be ischemic. An estimated 20% to 30% of lesions that are between the 30% and 50% range will be ischemic.
“When we have more of a physiologic basis for understanding that stenosis ischemia can occur at a variety of percent stenosis, then we can actually drive decision-making regarding the patient in terms of medical management decisions as well as decisions regarding revascularization,” Shaw said.
Taking action after imaging tests is crucial to proving a link from risk to treatment, according to the presentation. Although health care plans are keeping an eye on this, research shows that reduced efforts in following up after tests is not affecting care. In the SPARK registry, half of patients with moderate to severe ischemia underwent invasive angiography. A small percentage of patients with ischemia are recommended anti-ischemic therapies, referred to cardiac rehabilitation or given an exercise prescription.
Although the cardiologist is the imager, they can work with the referring physician and the patient to develop a relationship that becomes essential to patient care, according to the presentation.
“Making yourself essential to the health care system means that you are the care coordinator,” Shaw said. “That doesn’t mean you have to check everything, but you have to be the person not only to justify the procedure in terms of appropriate use, employ standardized image protocol and safety optimization. You have to have standardized image interpretation; clinical management recommendations have to be a core component.”
This pathway can lead to patient satisfaction and confidence in their care, which can also lead to compliance, Shaw said.
Through research, new imaging methods and a focus on patient care, more progress can be made.
“We can be the agents of change,” Shaw said. “We know the most about cardiovascular imaging. Don’t let others define those strategies and those policies for us. So as you start to think about these goals of quality, lower cost, safety, efficiency, outcomes, start to think about outreach, interconnectivity, educational activities for your referring physicians and patients.” – by Darlene Dobkowski
Shaw LJ. Evolving, innovating and revolutionary changes in cardiovascular imaging — We have only begun. Presented at: American Society of Nuclear Cardiology; Sept. 14-17, 2017; Kansas City, Mo.
Disclosure: Shaw reports no relevant financial disclosures.