Cardiac MRI in Front Line for the Diagnosis of Coronary Artery Disease as the Etiology of Left Ventricular Dysfunction

Study Overview
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Brief Summary
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When a patient is newly diagnosed of systolic dysfunction without obvious etiology (such as rhythmic, ischemic, or valvular disease), most of the time a coronary angiography is performed. In this situation, the investigators aim to evaluate a strategy with CMR as the front line exam, and invasive coronary angiography performed only in case of ischemic scar on CMR

Detailed Description
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Reduced Left Ventricular Ejection Fraction (LVEF) is estimated to be present in 3-7% of the population. With a survival rate between 25-40% at 5 years after a first hospitalization, prognosis of heart failure is similar to that of most cancers. Its treatment and prognosis strongly depend on the etiology, and coronary artery disease is the most frequent one. Identifying coronary artery disease determines care, including medical treatment (aspirin, statins) and revascularization strategies (stent implantation, coronary artery bypass grafting). Once an echocardiography has revealed an LV reduction, with no clear etiology at clinical or echographical examination, coronary angiography is almost systematically performed. But among the 260,000 invasive coronary angiographies performed each year in France (all indications included), 30-60% are normal (no obstructive coronary artery). And among patients with unexplained LV dysfunction, this rate reaches 70-74%… Thus the efficiency of systematic coronary angiography is questionable for these latter. Besides, angiography is invasive, and associated with multiple risks and costs. Cardiac Magnetic Resonance Imaging (CMR) is very specific and sensitive for detecting myocardial infarction. Small series concluded that a reduction of LVEF due to coronary artery stenosis should have at least one myocardial scar, detected on CMR. But the available data was not enough to change guidelines and clinical practice. In our retrospective study performed on 305 patients, the sensibility of CMR for coronary stenosis was 96%. Furthermore, CMR as a first-line exam would have avoided 71% of coronary angiography, saving 216 days of hospitalization and 329.054 € (1.079€/patient). These results reinforce the previous data but are not definitive. The aim of this study is to provide a high level of evidence of the benefits and safety of a strategy based on CMR as the front line exam for newly diagnosed systolic dysfunctions. The primary objective is to evaluate the sensitivity of CMR for predicting the presence of angiographically significant coronary artery stenosis in patients with reduced LVEF. The primary endpoint is the sensitivity of CMR for predicting the presence of significant coronary artery stenosis on coronary angiography in patients with reduced LVEF. The objective of the economic evaluation is to estimate the incremental (or decremental) cost effectiveness of using CMR first compared to coronary angiography first. For unexplained LV dysfunction, patient will be addressed for CMR first and coronary angiography within 2 weeks after (instead of systematic coronary angiography and unsystematic CMR). CMR and coronary angiography will be performed in all patients. Independent committees will blindly review CMRs and coronary angiographies at the end of the study.

Official Title
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Prospective Multicentric Study for the Diagnostic Performance of CArdiac MAgnetic REsonance Imaging Used First for the Diagnosis of Coronary Artery Disease as the Etiology of Left Ventricular Dysfunction

Conditions
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Ischemic Cardiomyopathy

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years Left Ventricular Ejection Fraction ≤ 45% on transthoracic echocardiography Informed signed consent Patient having had a preliminary clinical examination Exclusion Criteria: Known significant coronary artery stenosis (history of myocardial infarction or coronary artery stenosis). Formal indication for coronary angiography other than LV dysfunction (typical angina, acute coronary syndrome, …). Obvious etiology for LV dysfunction (valvular, rhythmic…). Pregnancy or breastfeeding. Other contraindication for CMR (severe allergy to gadolinium known), or coronary artery angiography. First diagnosis of LVEF dysfunction > 8 weeks. Non covered patient by the social security, the CMU Patients under guardianship, or unable to give consent

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensitivity of CMR for predicting the presence of significant coronary artery stenosis on coronary angiography in patients with reduced LVEF. | The primary endpoint is the sensitivity (and its 95% confidence interval) of CMR for the diagnosis of significant coronary artery stenosis on coronary angiography in patients with reduced LVEF. This sensitivity is the following ratio: Number of patients with an ischemic scar on CMR and a significant coronary artery stenosis on coronary angiography / Number of patients with a significant coronary artery stenosis on coronary angiography. | up to 8 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Evaluation of the other diagnostic performances indices of CMR for the diagnosis of angiographically significant coronary artery stenosis in patients with reduced LVEF | Sensitivity¸ specificity, positive predictive value and negative predictive value (and their 95% confidence interval) of CMR for the diagnosis of significant coronary artery stenosis on coronary angiography in patients with reduced LVEF | up to 8 weeks | 
| Evaluation of the diagnostic performances of CMR for predicting angiographically significant coronary artery stenosis in patients with reduced LVEF requiring revascularization. | Sensitivity¸ specificity, positive predictive value and negative predictive value (and their 95% confidence interval) of CMR for the diagnosis of significant coronary artery stenosis on coronary angiography in patients with reduced LVEF requiring revascularization | up to 8 weeks | 
| Analysis of the concordance of CMR and coronary artery angiography in terms of coronary artery territory in patients with coronary stenosis. | κ concordance coefficient between CMR and coronary angiography for the diagnosis of affected myocardial territory in patients with coronary artery stenosis. | up to 8 weeks | 
| Additional value of CMR for the etiologic diagnosis of reduced LVEF including non-ischemic (LV non compaction, myocarditis …). | Proportion of different etiological diagnosis of reduced LVEF provided only by CMR | up to 8 weeks | 
| Additional value of CMR for the diagnosis of complications of reduced LVEF (LV thrombus mainly). | Number of patients for whom a complication due to LVEF reduction (LV thrombus, left ventricular dys-synchrony, pre-ruptured left ventricular wall...) is provided only by CMR. | up to 8 weeks | 
| Additional value of CMR for the decision of coronary artery revascularization. | Proportion of patients with coronary stenosis on the coronary angiography for whom CMR change the decision of revascularization, due to the absence of myocardial viability. | up to 8 weeks | 
| Evaluate the reproducibility of the interpretations of CMR for ischemic cardiomyopathy. | κ concordance coefficient between the first interpretation of CMR (in the participating centers), and the second (by the CMR reading committee). | up to 8 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Coronary artery disease, cardiac MRI, heart failure