Special Issue of JACC: Cardiovascular Imaging Looks at Randomized Trials in Imaging

A special issue of JACC: Cardiovascular Imaging, published March 6, focuses on randomized trials in cardiovascular imaging. A collection of original research, imaging perspectives and state-of-the-art papers highlight the role outcomes-based imaging evidence plays in understanding, diagnosing and treating cardiovascular disease.

Jagat Narula, DM, MD, PhD, MACC, Leslee J. Shaw, PhD, FACC, and Pamela Douglas, MD, MACC, use the Editor’s Page to highlight the community’s advances in cardiovascular imaging, stating that “10 years ago, the idea of a special issue of JACC: Cardiovascular Imaging devoted to randomized controlled trials would not have been possible.” They suggest six areas to prioritize next, and underscore that “how we address these questions will define the next decade of cardiovascular imaging research.

According to Douglas, who served as guest editor for the issue, “Imaging constitutes a large and essential component of cardiovascular care, but the evidence base underlying its use is much weaker than that for new drug and devices. However, in the last 10 years, researchers, regulators and payors have asked that the value of imaging, beyond its ability to detect or exclude disease, be demonstrated in rigorous prospective research. This special issue pulls together reviews on the methods required to meet these new higher evidentiary standards, on diseases and imaging indications in which randomized trials now provide robust support for imaging’s value, and in prospective original research. Thus this issue, in addition to provide a comprehensive compendium of the current randomized trial data in imaging, marks a maturation of cardiovascular imaging science and provides a road map for future research.”

Highlights of the special include:

Imaging Guided Cardio-Protective Treatment in Elderly: Advanced echocardiography identified evidence of stage B heart failure (SBHF) in elderly individuals at risk of heart failure, but did not contribute to improved clinical outcomes, according to a study by Hong Yang, BMed, et al. Of the 818 asymptomatic patients, 219 were found to have SBHF and treatment was advised. After one year, only 43 percent initiated therapy, nine percent died from cardiovascular causes and new heart failure, and four percent had withdrawn from the study. In an accompanying editorial, James N. Kirkpatrick, MD, FACC, and James Lee, MD, note that, “larger trials with better treatment adherence” are needed to prove the direct benefits of imaging on clinical outcomes.

Myocardial Infarct Size by CMR: To optimize the design of future randomized controlled trials (RCT) and facilitate future comparisons, a study led by Heerajnarain Bulluck, MBBS, et al., made recommendations to standardize the assessment of myocardial infarct size by cardiovascular magnetic resonance (CMR) in segment elevation myocardial infarction patients. Researchers evaluated 62 RCTs between January 2006 and November 2016. Results showed that a third of the RCTs did not provide CMR scanner details, contrast agent and dosage used, and the method used to determine myocardial infarction (MI) size. “Future RCTs should report details on the execution of the scan and the method used for MI size quantification, to facilitate comparison between RCTs,” they conclude.

The MRI Sub-Study in AIM-HIGH: Among patients with clinically established atherosclerotic disease, high-risk carotid plaque features were “strongly associated” with systemic cardiovascular outcomes, according to a sub-study of the AIM-HIGH trial by Jie Sun, MD, et al. The authors conclude that “markers of carotid plaque vulnerability may serve as novel surrogate markers for systemic atherothrombotic risk.” However, in an accompanying editorial, Salim S. Virani, MD, PhD, FACC, and Christie M. Ballantyne, MD, FACC, state that “before [magnetic resonance imaging] can be used as a routine imaging modality for [atherosclerotic cardiovascular disease] risk estimation, more data are needed.”

Imaging Endpoints in Clinical Trials: A perspective by Linda D. Gillam, MD, MPH, FACC, et al., discusses requirements for cardiovascular imaging endpoints to ensure data acquired is accurate, reproducible and unbiased. They point out the need for communication between site images and study representatives, standardized operating procedures for core laboratories laid out in a study-specific imaging manual, and optimized image acquisition and interpretation.

Use of Imaging in the Primary Prevention of CVD: Coronary artery calcium (CAC) scanning may be the optimal approach for cardiovascular disease screening, according to a perspective by Alan Rozanski, MD, FACC, et al. The authors looked at five randomized trials, and conclude that CAC scanning might be “particularly attractive … due to its ease of acquisition, low cost and radiation exposure, its proven ability to predict both short and long-term risk, and the widespread understanding and ease of understanding the ‘CAC score’ by clinicians.” In an accompanying editorial, Darryl P. Leong, MBBS, MPH, M.Biostat, PhD, et al., state that “the available evidence does not support the widespread use of coronary imaging for the identification of asymptomatic [coronary artery disease].” As such, they explain that “it would be premature to recommend screening using imaging techniques in asymptomatic individuals as part of a routine clinical or population health strategy,” until further studies are conducted and demonstrate clinical benefit.

SIHD Comparative Effectiveness Trials: Leslee J. Shaw, PhD FACC, et al., highlight the current landscape in stable ischemic heart disease (SIHD) imaging, and explain that challenges continue to exist in the design and implementation of SIHD comparative effectiveness research studies. They conclude that no one modality was found to be superior to others or across patient subgroups. In an accompanying editorial, William E. Boden, MD, FACC, and Judith L. Meadows, MD, suggest that comparative effectiveness research trial design will need to incorporate “traditional clinical trial and ‘real world’ observational evidence, adopt pragmatic trial design through the leveraging of existing registries and electronic medical records outcomes data, and embrace the continued development of learning health environments that may more effectively enhance care and treatment decision.”

Acute Chest Pain Imaging Use: In a state-of-the-art paper, Gilbert L. Raff, MD, FACC, et al., explore RCTs that provide the evidence-base for diagnostic strategies for acute chest pain patients. They conclude that future studies might consider exploring a combination of anatomical and functional imaging and other novel technologies. In an accompanying editorial, Deepak L. Bhatt, MD, MPH, FACC, and Viviany R. Taqueti, MD, MPH, FACC, state that “much of this appeal comes from combining a technique that is sensitive for diagnosis of [coronary artery disease]with one that is specific for diagnosis of ischemia. They suggest proceeding with caution and “look with enthusiasm to future trails” for definitive answers.

Functional Testing For Ischemia and Viability: Ongoing studies, including FAME 3, ISCHEMIA and AIMIHF (IMAGE-HF), will provide evidence needed to support practice changes to improve outcomes of patients with SIHD, according to a perspective by Lisa M. Mielniczuk, MD, et. al. “Until such data are available, we must be cautious and cognizant of potential dogma around current paradigms which apply ischemia or viability testing to guide revascularization decisions in patients with SIHD,” they conclude. In an accompanying editorial, Julio A. Panza, MD, FACC, and Robert O. Bonow, MD, MACC, highlight the importance of “how seemingly well-established notions must be constantly re-evaluated, particularly in the context of the continued development of new diagnostic techniques.”

Quality Improvement in Imaging: A perspective by Kavitha M. Chinnaiyan, MD, FACC, and Rory B. Weiner, MD, states that quality in cardiovascular imaging must focus on three main factors: laboratory and equipment, personnel involved and the imaging process. They explain that while studies and advancements have taken place over the past 10 years, only a few were randomized trials of quality improvement programs. In an accompanying editorial, Thomas H. Marwick, MBBS, PhD, MPH, FACC, underlines the need for rigorous research so that high-quality evidence informs future quality control efforts.

Read the full issue of JACC: Cardiovascular Imaging.


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