Prognostic Value of Hemodynamic Forces at Rest and Stress Compared to Adenosine and Dobutamine Stress Cardiac Magnetic Resonance

In total 112 patients who underwent coronary artery bypass surgery (CABG) subjected to stress CMR examination on two separate occasions with both stressors; dobutamine and adenosine for assessment of myocardial ischemia as result of typical /atypical angina pectoris. The results from dobutamine (namely, detection of wall motion abnormalities) and adenosine stress CMR (namely, detection of perfusion abnormalities) will be compared with the values obtained from the measures of the hemodynamic forces of the LV (i.e., changes in the intraventricular pressures during systole and diastole). The dimensionless root mean square (FRMS) is computed over the entire heartbeat as a measure of the overall force amplitude. In addition, LV global longitudinal strain (GLS) and LV global circumferential strain (GCS) will be measured using a CMR feature tracking techniques. The expected results are as follows: Dobutamine wall motion analysis in combination with perfusion imaging has the highest diagnostic accuracy for the detection of ischemia in patients after bypass surgery and outperforms pure dobutamine wall motion or perfusion analysis and adenosine perfusion. Whereas, perfusion imaging with both stressors reflects the extent of ischemia more precisely than wall motion analysis. Nevertheless, assessment of hemodynamic forces adds to the diagnostic accuracy as well as the prognostic value of stress CMR in post-CABG patients, in whom stress testing with either or both stressors might fail to precisely define myocardial ischemia or reflect an associated subtle cardiac dysfunction.