Prediction of Cardiac Events in Patients With Reduced Left Ventricular Ejection Fraction With Dobutamine Cardiovascular Magnetic Resonance Assessment of Wall Motion Score Index

Abstract

Objectives To assess the utility of dobutamine cardiovascular magnetic resonance (DCMR) results for predicting cardiac events in individuals with reduced left ventricular ejection fraction (LVEF). Background It is unknown whether DCMR results identify a poor cardiac prognosis when the resting LVEF is moderately to severely reduced. Methods Two-hundred consecutive patients aged 30 to 88 (average 64) years with a LVEF ≤55% that were poorly suited for stress echocardiography, underwent DCMR in which LV wall motion score index (WMSI), defined as the average wall motion of the number of segments scored, was assessed at rest, during low dose, and after peak intravenous infusion of dobutamine/atropine. All participants were followed for an average of 5 years after DCMR to ascertain the post testing occurrence of cardiac death, myocardial infarction (MI), and unstable angina or congestive heart failure warranting hospitalization. Results After accounting for risk factors associated with coronary arteriosclerosis and MI, a stress induced increase in WMSI during DCMR was associated with future cardiac events (p< 0.001). After accounting for resting LVEF, a DCMR stress induced change in WMSI added significantly to predicting future cardiac events (p=0.003), but this predictive value was confined primarily to those with a LVEF >40%. Conclusions In individuals with mild to moderate reductions in LVEF (40% to 55%), dobutamine induced increases in WMSI forecast MI and cardiac death to a greater extent than an assessment of resting LVEF. In those with a LVEF < 40%, a dobutamine induced increase in WMSI does not predict MI and cardiac death beyond the assessment of resting LVEF.

Assessing the Prognostic Value of Cardiovascular Imaging

“…It was also a greater CD/MI rate than that reported in previous prognostic stress CMR studies (Table), including a study in patients with LV dysfunction. 1 Hence, given the risk profile of these patients, the generalizability of results from this cohort is unclear.…”

“…Nonetheless, stress CMR techniques are in their relative infancy, and evidence is only now beginning to accumulate justifying their use. Whereas several studies have examined the diagnostic accuracy of stress CMR, only recently have sufficient numbers of patients been collected to assess the prognostic value of this approach [1][2][3][4][5] (Table). 6 The validation of stress CMR is more complex than that of previous modalities, inasmuch as a routine study would include rest function and structure, stress perfusion, and viability images (as well as, potentially, rest perfusion).…”

Cardiovascular Magnetic Resonance

“…43 Low cardiac event rates are associated with normal stress CMR, and increasing risk is seen with increasing extent of ischemia. 44,45 Stress CMR can be combined with tagging to quantify myocardial strain, which improves diagnostic accuracy, 46 reduces observer variability, 47 and can be combined with perfusion imaging. 48 …”

The Prognostic Implications of Cardiovascular Magnetic Resonance

“…38 In a study by Kuijpers et al 39 (nϭ299, follow-up 2 years), patients with inducible WMAs had a higher MACE rate (18% versus 0.56%; Pϭ0.001). In mild LV impairment (EF, 40% to 55%), Dall'Armellina et al 40 (nϭ200; follow-up, 5 years) demonstrated that inducible WMAs were associated with a greater risk of MI and cardiac death beyond that associated with the resting EF and/or cardiac risk factors (PϽ0.001), and they were the only independent predictor on multivariate analysis (HR,1.7; p 0.008). However, in this study, in severe LV impairment (EF Ͻ40%), induced defects were not additionally predictive of outcome over rest EF.…”