Cardiac Magnetic Resonance Can Exclude Clinically Relevant Coronary Artery Disease

MedicalResearch.com Interview with:

Pr. Juerg Schwitter MD Médecin Chef Cardiologie Directeur du Centre de la RM Cardiaque du CHUV Centre Hospitalier Universitaire Vaudois - CHUV Suisse

Pr. Schwitter

Pr. Juerg Schwitter MD
Médecin Chef Cardiologie
Directeur du Centre de la RM Cardiaque du CHUV
Centre Hospitalier Universitaire Vaudois – CHUV
Suisse 

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Coronary artery disease (CAD) is still one of the leading causes of death in the industrialized world and as such, it is also an important cost driver in the health care systems of most countries. For the European Union, the estimated costs for CAD management were 60 billion Euros in 2009, of which approximately 20 billion Euros were attributed to direct health care costs (1). In 2015, the total costs of CAD management in the United States were estimated to be 47 billion dollars (2).

Substantial progress has been achieved regarding the treatment of CAD including drug treatment but also revascularizations procedures. There exists a large body of evidence demonstrating myocardial ischemia as one of the most important factors determining the patient’s prognosis and reduction of ischemia has been shown to improve outcome.

On the other hand, techniques to detect CAD, i.e. relevant myocardial ischemia, were insufficient in the past. Evaluation of myocardial perfusion by first-pass perfusion cardiac magnetic resonance (CMR) is now closing this gap (3) and CMR is recommended by most international guidelines for the work-up of known or suspected CAD (4,5).

Still, a major issue was not clarified until now, i.e. “how much ischemia is required to trigger revascularization procedures”. Thus, this large study was undertaken to assess at which level of ischemia burden, patients can be safely deferred from revascularization and can be managed by risk factor treatment only. Of note, this crucial question was addressed in both, patients with suspected CAD but also in patients with known (and sometimes already advanced) CAD, thereby answering this question in the setting of daily clinical practice.

MedicalResearch.com: What are the main findings?

Response: In this study, 1024 patients were all investigated by CMR (including first-pass perfusion assessment, as well as functional and viability assessment) and were followed-up prospectively for 2.5±1.0 years. The primary endpoint was a composite of cardiac death, non-fatal myocardial infarction (MI) and late coronary revascularization (>90 day post-CMR); the secondary end-point was a composite of the hard events of cardiac death and non-fatal MI.

This study shows that the prognosis is very good for patients with no or only 1 segment ischemic (on the 16-segment left ventricular model) with an annual event rate of 0.44% for cardiac death and not-fatal MI. Interestingly, also patients with ischemia on Cardiac Magnetic Resonance, but revascularized (within 90 days post-CMR), showed an excellent prognosis with no cardiac death and no infarcts.

Conversely, patients with an ischemic burden of more than one segment and who were not revascularized, had a reduced prognosis with an annual event rate of 3.9% for cardiac death and non-fatal MI – and it was 9.7% per year when including late (i.e. >90 day post-CMR) revascularizations.

MedicalResearch.com: What should readers take away from your report?

Response: There are three major messages from this study to take home:

  • First, Cardiac Magnetic Resonance is an excellent tool to safely exclude clinically relevant CAD in patients with suspected CAD.
  • Second, in patients with both, suspected or known CAD, the CMR method is ideal to manage these patients as it adds important information for clinical decision making, i.e. to revascularize or not.
  • Third, small ischemic territories (only one segment ischemic) are associated with a good prognosis and these patients can safely be deferred from revascularizations.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response:   In this study we derived a simple score (integrating some clinical data with Cardiac Magnetic Resonance-derived functional, viability, and ischemia data) to predict the prognosis of the patients after a CMR examination. This score should be confirmed in larger, ideally multicenter data. Save deferral of patients from revascularizations should also result in cost savings as shown in previous model calculations (6). Such cost effectiveness results should be tested in prospective trials applying the ischemia threshold for deferrals as identified in this study.

MedicalResearch.com: Is there anything else you would like to add?

Response:   The excellent quality work of the physicians, technicians, and research nurses, should be acknowledged who made this study possible and who provide this service on a clinical basis. Also, the positive collaboration between the Cardiovascular Department and the Radiological Department in supporting the Cardiac MR Center (CRMC) of the University Hospital Lausanne (CHUV) is greatly appreciated. The CRMC receives research funds from Medtronic Healthcare, Bayer Healthcare, and Bracco Healthcare.

MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.

  1. J. Leal et al. European Cardiovascular Disease Statistics, European Heart Network and European Society of Cardiology, Edition 2012. ISBN 987-2-9537898-1-2
  1. AS. Go et al., Heart Disease and Stroke Statistics–2013 Update: A Report From the American Heart Association, Circulation. 2013;127:e6-e245
  1. J. Schwitter et al. CMR-Update, Chapter 4 – Coronary Artery Disease, 2. Edition. Lausanne, Switzerland
  1. G. Montalescot et al. ESC guidelines on the management of stable coronary artery disease: The Task Force on the management of stable coronary artery disease of the European Society of Cardiology. Eur Heart J 2013;34:2949-3003.
  1. SD. Fihn et al. 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS Guideline for the Diagnosis and Management of Patients With Stable Ischemic Heart Disease: J Am Coll Cardiol 2012;60:e44–e164.
  1. K. Moschetti et al. Cost-minimization analysis of three decision strategies for cardiac revascularization: results of the “suspected CAD” cohort of the european cardiovascular magnetic resonance registry. J Cardiovasc Magn Reson 2016;18:1-10

Citation:

JACC: Cardiovascular Imaging

Prognostic Value and Optimal Ischemic Threshold for Revascularization

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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