Discover how Marc Dewey, Heisenberg Professor of the German Research Foundation and leading researcher in cardiovascular imaging, is revolutionizing coronary artery disease (CAD) diagnosis. Through noninvasive computed tomography (CT) scans, he’s offering accurate, safe, and efficient alternatives to invasive procedures. Dive into his groundbreaking research that’s set to transform CAD diagnosis.

Which wall does your research break?

Coronary artery disease (CAD) is the most common cause of death globally. Invasive coronary angiography (cardiac catheterization) is the reference standard for the diagnosis of CAD. However, invasive coronary angiography using cardiac catheterization is associated with rare but major complications, and only 38% of invasive coronary angiographies show CAD. More than 4 million cardiac catheterizations for invasive coronary angiography are performed year after year in European countries alone and it would be an enormous benefit for society if these could be replaced by reliable and noninvasive diagnostic imaging. For computed tomography (CT), a noninvasive imaging alternative to cardiac catheterization for invasive coronary angiography, we found high accuracy in a worldwide collaboration with overall sensitivities of 95% for detection of obstructive stenosis and a resulting high negative predictive value in patients with an intermediate pretest probability of CAD (BMJ 2019, COME-CCT). If better patient outcomes, including fewer clinical events or procedure-related complications, could be confirmed for CT in a randomized trial in comparison to cardiac catheterization, this would change clinical practice and be of benefit to society because it would ultimately lead to faster and less invasive but highly accurate diagnosis in individuals with suspected CAD of intermediate probability. Moreover, it is not uncommon for CT acquired for suspected CAD to also reveal extracardiac findings: in about 10% of the CT examinations performed for this purpose, the cause of the chest pain is found outside the heart. CT often also depicts more of the heart disease itself: for example, early deposits (plaques) in the coronary vessels are more often detected when a CT scan is obtained: in the DISCHARGE study, CT detected non-obstructive deposits in 36% of patients versus 22% of patients in the group examined by invasive coronary angiography.

What inspired or motivated you to work on your current research or project?

Over the last 20 years, my team and I have made crucial refinements to CT that have helped turning it into a highly accurate noninvasive clinical imaging test for CAD. In the diagnosis of obstructive CAD, CT is an accurate, noninvasive alternative to invasive coronary angiography in patients with stable chest pain and an intermediate pretest probability of obstructive CAD. Nevertheless, invasive coronary angiography is the long-established reference standard for the diagnosis of obstructive CAD and has been used since the 1970-ies. Importantly, invasive coronary angiography enables coronary revascularization (e.g., stent placement) during the same procedure. It must be noted, though, that elective invasive coronary angiography is associated with rare but major procedure-related complications. Therefore, CT may be better in guiding the treatment of patients with stable chest pain. CT has generated interest in ruling out obstructive CAD noninvasively with a low risk of adverse events while it identifies patients who are appropriate candidates for coronary revascularization. In the SCOT-HEART (Scottish Computed Tomography of the Heart) trial, CT was added to standard care, which included functional testing, and was compared with standard care alone. The use of CT was associated with a significantly lower incidence of major adverse cardiovascular events. Moreover, in two small randomized trials comparing CT with invasive coronary angiography (CAD-Man and CONSERVE), an initial CT strategy resulted in a lower number of invasive procedures, a higher percentage (75%) of invasive coronary angiograms showing obstructive CAD, and similar clinical outcomes, which included hospitalization and revascularization. We therefore conducted the DISCHARGE (Diagnostic Imaging Strategies for Patients with Stable Chest Pain and Intermediate Risk of Coronary Artery Disease) trial to compare CT with invasive coronary angiography as an initial diagnostic imaging strategy for guiding the treatment of patients with stable chest pain clinically referred for invasive coronary angiography. We did this together with the DISCHARGE trial family: a tremendously dedicated interdisciplinary group at 26 clinical centers in 16 European countries.

In what ways does society benefit from your research?

We conducted the randomized DISCHARGE trial in 16 European countries to compare the performance of CT and cardiac catheterization for invasive coronary angiography in guiding the treatment of patients with suspected CAD. The European Commission funded DISCHARGE, and we coordinated this 31-partner project. The DISCHARGE trial showed improved patient outcomes, namely a reduction of cardiovascular events by 30% and complications by 74%, when CT was used instead of invasive coronary angiography (NEJM 2022). We also showed that both women and men benefitted from CT as the initial diagnostic test (BMJ 2022). Recently, we also conducted an international clinical consensus on coronary artery stenosis and atherosclerosis imaging, which confirmed the primary role of CT in patients with intermediate probability of CAD (Nature Reviews Cardiology 2023). Based on these results and the DISCHARGE trial, CT is now being implemented internationally and replacing cardiac catheterization for invasive coronary angiography on a large scale to the benefit of patients and society. In Germany alone, using CT instead of cardiac catheterization for invasive coronary angiography in the appropriate patients with stable chest pain and an intermediate pretest probability of CAD could lead to a reduction in major procedure-related complications in approximately 4000 patients every year and a reduction in annual cost for the health care system of approximately 0.5 billion Euros.

Looking ahead, what are your hopes or aspirations for the future based on your research or project?

It is important to ensure that CT examinations are carried out in qualified and certified cardiac imaging centers, of which there are about 110 in Germany. But it is also crucial to use CT only for patients who really benefit from it: this means that it is not an option for either patients with acute symptoms or those who have a high probability of CAD and should better be examined with invasive coronary angiography right away or for patients with only a low probability of CAD in whom no testing is needed. We must not start examining patients with CT unless they have appropriate probability of CAD. This is because if we do start examining patients with low probability of CAD, we will add another 1 billion Euros a year for CT to the two billion Euros we spend on cardiac catheterizations for invasive coronary angiography in Germany. For patients with a high probability of CAD, guidelines currently recommend that invasive coronary angiography be carried out in order to decide, on the basis of the findings, together with the patient and on the basis of an interdisciplinary discussion, whether treatment by percutaneous coronary stent placement using cardiac catheterization or coronary artery bypass surgery is the best treatment in each case. Deciding who should have a CT scan and who should undergo invasive coronary angiography is not rocket science. Two “pre-test” methods for determining the probability of obstructive CAD are established: first, there is the Marburg Heart Score, which is mainly used in general practitioner and internal medicine practices, and takes into account the patient’s age and medical history in addition to current symptoms such as chest pain. Second, there is also the DISCHARGE pre-test score for secondary care at centers or hospitals, which estimates the probability of CAD based on the patient’s age, gender and current symptoms. This is a very good and easy way to determine the likelihood of CAD and will be crucial to ensure a bright future for noninvasive CT imaging of coronary artery disease.

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