In Germany, coronary CT offers an accurate and less burdensome alternative to cardiac catheterisation for evaluating suspected coronary artery disease, but it is still underused. The IMPRO stepped-wedge trial tests a new, nationwide care model (NVF) in 16 regions to improve guideline-based intersectoral implementation of coronary CT and assess its impact on cardiovascular outcomes and healthcare costs. If effective, the model of care (NVF) could be adopted across Germany to enhance care quality while reducing unnecessary procedures and expenses.
In Germany, more than 700,000 patients with chest pain undergo cardiac catheterisation each year. The most common reason is suspected coronary artery disease-the leading cause of death worldwide. Proportionally, more cardiac catheterizations are performed in Germany than in any other country. Coronary computed tomography (coronary CT) is available as an alternative diagnostic method to cardiac catheterization. The advantages of coronary CT include a lower complication rate, greater accuracy in detecting deposits in the coronary arteries, reduced burden for patients, and less procedural effort. The aim of the partners in the IMPRO project is to optimize the implementation of coronary CT in routine clinical care following the resolution of the Federal Joint Committee on January 18, 2024, while at the same time avoiding overuse. For this purpose, a new model of care will be tested in 16 different regions across 12 federal states in Germany. This model is intended to improve primary and cross-sectoral care for patients with suspected coronary artery disease. The primary goal of the nationwide study is to determine whether the new model of care helps reduce cardiovascular events, such as heart attacks and strokes, in patients with suspected coronary artery disease. The researchers will also analyze how patients respond to this type of treatment and whether it leads to cost savings. The project is funded for 39 months with a total of approximately 9.3 million euros. If successful, the new model of care could be implemented nationwide to improve the treatment of patients with suspected coronary artery disease and to avoid unnecessary costs for the healthcare system.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
DIAGNOSTIC
Masking
SINGLE
Enrollment
3,369
The intervention consists of structural and procedural components designed to improve cross-sectoral coordination in the diagnostic work-up of patients with suspected coronary artery disease (CAD). It builds upon the 2024 National Disease Management Guideline (NVL KHK 2024) and comprises three main components: (1) evidence-based initial assessment and indication for imaging diagnostics, (2) shared decision-making between primary care physicians, radiologists, and patients, and (3) quality-assured CT imaging and structured reporting in certified centres. Participating sites receive structured training, feedback, and centralized quality monitoring.
Universitätsklinikum Augsburg, Diagnostische und Interventionelle Radiologie und Neuroradiologie
Augsburg, Germany
RECRUITINGUniversitätsklinikum Augsburg, Institut für Allgemeinmedizin
Augsburg, Germany
RECRUITINGRHOEN-Klinikum AG, Campus Bad Neustadt, Klinik für Radiologie
Bad Neustadt an der Saale, Germany
RECRUITINGCharité-Universitätsmedizin Berlin, Institut für Allgemeinmedizin
Berlin, Germany
Major Adverse Cardiovascular Events (MACE)
Composite endpoint: Major Adverse Cardiovascular Events (MACE) including cardiovascular death, myocardial infarction, stroke, and procedure-related complications from diagnostic testing and subsequent management/therapy in the two randomization groups. Procedure-related complications (major and minor) are defined in the subsequent outcome measure and include events occurring during or within 48 hours after CT or ICA or related tests or revascularization procedures.
Time frame: From enrolment to 12 months for primary MACE analysis in the G-BA-funded IMPRO trial; extended follow-up to 5 years for MACE (cardiovascular death, myocardial infarction, stroke) excluding procedure-related complications; data at 3, 12 months and 5 years
Prospective Primary Safety Endpoint: Procedure-related Complications
Rate of procedure-related complications by diagnostic imaging modality and by interventional/surgical treatments (PCI, CABG). Includes major and minor complications. Major complications: events occurring during or within 48 hours after CT or ICA or related tests or revascularization procedures, including death, nonfatal myocardial infarction, nonfatal stroke, complications prolonging hospitalization ≥24 hours, coronary/aortic dissection, cardiogenic shock, cardiac tamponade, retroperitoneal bleeding, cardiac arrhythmia (ventricular tachycardia/fibrillation), or cardiac arrest. Minor complications: events occurring during or within 48 hours after CT or ICA or related tests or revascularization procedures not meeting major criteria, including hematoma or secondary bleeding at the puncture site, bradycardia, angina pectoris without myocardial infarction, allergic reaction to contrast media, hypotension requiring treatment, infection, thrombosis, or arteriovenous fistula.
Time frame: 3 months and 12 months
Indication quality
1\) Agreement of the diagnostic decision with the pre-test probability (PTP, below 15%, 15-50%, above 50% criterion) with the National Health Services guidelines for suspected coronary artery disease and the statistical distribution of PTP values across the scale (NVL KHK 2024), measured using the updated DISCHARGE PTP calculator in the two randomisation groups, 2) Agreement of the mean pre-test probability with the prevalence of obstructive coronary artery disease (CAD) defined as at least one at least 50% coronary artery diameter stenosis on coronary computed tomography angiography (CTA) and/or invasive coronary angiography (ICA) in the two randomisation groups.
Time frame: From enrollment to 12 months (with follow-up data collection at baseline, 3 months, 12 months)
Functional test rates
Rate of functional tests performed during the follow-up period (stress electrocardiography (ECG), cardiac stress magnetic resonance imaging (MRI), stress echocardiography, stress myocardial perfusion single-photon emission CT (SPECT), myocardial stress perfusion positron emission tomography (PET)) in the two randomisation groups.
Time frame: From enrollment to 12 months and 5 years (with follow-up data collection at 3 months, 12 months and 5 years)
Revascularization rates
Rate of coronary artery revascularisations (percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG)) performed during the follow-up period in the two randomisation groups.
Time frame: From enrollment to 12 months and 5 years (with follow-up data collection at 3 months, 12 months and 5 years)
Coronary CT angiography (CTA) rates
Rate of coronary CT performed during the follow-up period in the two randomisation groups.
Time frame: From enrollment to 12 months and 5 years (with follow-up data collection at 3 months, 12 months and 5 years)
Invasive coronary angiography (ICA) rates
Rate of ICA procedures performed during the follow-up period in the two randomisation groups.
Time frame: From enrollment to 12 months and 5 years (with follow-up data collection at 3 months, 12 months and 5 years)
Invasive coronary angiography (ICA) results
Rate of diagnostic findings on the ICA procedures performed in the two randomisation groups (obstructive or non-obstructive CAD or no signs of CAD) to assess the yield of ICA defined as the proportion of ICAs performed in both randomisation groups demonstrating obstructive CAD.
Time frame: From enrolment to 12 months and 5 years (with follow-up data collection at 3 months, 12 months and 5 years)
Coronary CT angiography (CTA) results
Rate of diagnostic findings on the CTA procedures performed in the two randomisation groups (obstructive or non-obstructive CAD or no signs of CAD) to assess the yield of CTA defined as the proportion of CTAs performed in both randomisation groups demonstrating obstructive CAD.
Time frame: From enrolment to 12 months and 5 years (with follow-up data collection at 3 months, 12 months and 5 years)
Hospitalization due to chest pain
Rate of hospitalisations due to chest pain during the follow-up period in the two randomisation groups.
Time frame: From enrollment to 12 months and 5 years (with follow-up data collection at 3 months, 12 months and 5 years)
Emergency department visits due to chest pain
Rate of emergency department visits due to chest pain during the follow-up period in the two randomisation groups.
Time frame: From enrollment to 12 months and 5 years (with follow-up data collection at 3 months, 12 months and 5 years)
Assessability of coronary CTs
Proportion of non-diagnostic coronary CTs in the two randomisation groups.
Time frame: From enrollment to 12 months (with follow-up data collection at 3 months, 12 months)
Radiation exposure
Estimated radiation exposure of cardiac imaging tests including coronary CT, ICA, SPECT, and PET in the two randomisation groups in millisieverts (mSv).
Time frame: From enrollment to 12 months and 5 years (with follow-up data collection at 3 months, 12 months and 5 years)
Quality of life questionnaire
EQ-5D-5L: validated questionnaire with five dimensions (mobility, self-care, usual activities, pain/discomfort and anxiety/depression) and 5 levels (no problems, slight problems, moderate problems, severe problems and extreme problems) in the two randomisation groups.
Time frame: From enrollment to 3 months, 12 months and 5 years (with follow-up data collection at baseline 3 months, 12 months and 5 years)
Seattle Angina Questionnaire
SAQ-7 questionnaire (short version): disease-specific health status instrument for coronary artery disease (CAD) with seven items from the physical limitations, angina frequency, and quality of life domains in the two randomisation groups.
Time frame: From enrollment to 3 months, 12 months and 5 years (with follow-up data collection at baseline 3 months, 12 months and 5 years)
Total medical care costs (Ct) from the statutory health insurance perspective
Cumulative healthcare costs that can be mapped from routine health insurance data.
Time frame: 3 months, 6 months
Total medical care costs (Ct) from the perspective of society
Cumulative healthcare costs that can be mapped from primary data
Time frame: 3 months, 12 months, 5 years
Cost-effectiveness ratio (ICER) based on routine data collected by health insurers
ΔCt/ΔMACE: The calculated total costs are compared with MACE (primary endpoint). The results are presented as the incremental cost-effectiveness ratio (ICER). Data sources are routine data and patient survey distributed by the health insurers.
Time frame: 3 months, 6 months
Cost-effectiveness ratio (ICER) based on health care utilisation data
ΔCt/ΔMACE: The calculated total costs are compared with MACE (primary endpoint) in the two randomisation groups. The results are presented as the incremental cost-effectiveness ratio (ICER). Data source is primary health care utilisation data in the two randomisation groups.
Time frame: 3 months, 12 months, 5 years
Cost-utility ratio (ICUR) based on routine data collected by health insurers
ΔCt/ΔQALYs: The calculated total costs are compared with quality of life (secondary endpoint), measured using the standardised and validated EQ-5D-5L. The results are presented as the incremental cost-utility ratio (ICUR). Data sources are routine data and patient survey distributed by health insurers.
Time frame: 3 months and 6 months
Cost-utility ratio (ICUR) based on health care utilisation data
ΔCt/ΔQALYs: The calculated total costs are compared with quality of life (secondary endpoint), measured using the standardised and validated EQ-5D-5L. The results are presented as the incremental cost-utility ratio (ICUR). Data sources are primary data and patient quality of life survey in the two randomisation groups.
Time frame: 3 months, 12 months, 5 years
Marc Dewey, Prof. Dr.
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Charité - Universitätsmedizin Berlin, Klinik für Radiologie
Berlin, Germany
RECRUITINGUniklinik Köln, Institut für Diagnostische und Interventionelle Radiologie
Cologne, Germany
RECRUITINGUniversitätsklinikum Köln, Institut für Allgemeinmedizin
Cologne, Germany
RECRUITINGUniversitätsklinikum Düsseldorf, Institut für Allgemeinmedizin (ifam)
Düsseldorf, Germany
RECRUITINGUniversitätsklinikum Düsseldorf, Institut für Diagnostische und Interventionelle Radiologie
Düsseldorf, Germany
RECRUITINGRöntgeninstitut
Düsseldorf, Germany
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