Cardiovascular MR used in workup for myocarditis, various cardiomyopathies

CV magnetic resonance is most frequently used in the workup of myocarditis/cardiomyopathies — as well as for risk stratification for suspected coronary artery disease — and can affect the management of patients.

Researchers for the German pilot phase of the EuroCMR registry enrolled 11,040 consecutive patients who underwent CV magnetic resonance (CMR) imaging in the registry, 88% of whom received gadolinium-based contrast agents. The researchers evaluated the clinical value of CMR and aimed to define clinical questions for future protocols. Among the patients, 3,475 underwent CMR stress testing and the remaining patients did not.

According to the registry results, 21% of patients underwent adenosine perfusion and 11% underwent high-dose dobutamine CMR. Specialists completed complication-free procedures in about 99% of the patients. The most important indications for CMR were the workup of myocarditis and cardiomyopathies (31.9%), risk stratification of suspected CAD/ischemia (30.8%) and the assessment of myocardial viability (14.7%). The researchers reported that in nearly two-thirds of the cohort, CMR had a direct effect on the clinical management of the patients by providing new and unexpected diagnoses that resulted in therapeutic consequences. They also reported that in the analysis cohort, CMR was capable of satisfying all imaging needs in more than 86% of the patients.

“CMR is frequently performed in daily clinical practice in many participating centers,” the researchers wrote. “CMR imaging as used in the centers of the pilot registry is a safe procedure, has diagnostic image quality in more than 98% of cases and its results have strong impact on patient management.”

Bruder O. J Am Coll Cardiol. 2009;doi:10.1016/j.jacc2009.07.003.

These are certainly encouraging results that support the high clinical value of CMR imaging and are consistent with our own clinical experience. There are, it should be mentioned, significant differences between CMR in Europe and CMR in the United States. CMR services appear to be more widely utilized in Europe and CMR stress testing is more common. While all of the contributing sites appear to be expert centers, it should be noted that the serious complication rate for stress testing appears to be slightly higher than that reported in single center reports of large series but still very low at less than two per 1,000 cases.

In addition, in this case, the high degree of centralization of tertiary services in most European countries tends to facilitate availability of high quality services in high volume centers. While the data assembled is very promising, the authors are quite right to point out that outcomes data will really be essential to completely define the clinical role of CMR . This is a good start.

– Nathaniel Reichek, MD

Cardiology Today Editorial Board member