Impact of Stress Cardiac Magnetic Resonance Imaging on Clinical Care.

Given the rising costs of imaging, there is increasing pressure to provide evidence for direct additive impact on clinical care. Appropriate use criteria (AUC) were developed to optimize test-patient selection and are increasingly used by payers to assess reimbursement. However, these criteria were created by expert consensus with limited systematic validation. The aims of this study were therefore to determine (1) rates of active clinical change resulting from stress cardiovascular magnetic resonance (CMR) imaging and (2) whether the AUC can predict these changes. We prospectively enrolled 350 consecutive outpatients referred for stress CMR. Categories of "active changes in clinical care" due to stress CMR were predefined. Appropriateness was classified according to the 2013 AUC. Multivariate logistic regression analysis was used to identify factors independently associated with active change. Overall, stress CMR led to an active change in clinical care in about 70% of patients. Rates of change in clinical care did not vary significantly across AUC categories (p = 0.767). In a multivariate model adjusting for clinical variables and AUC, only ischemia (odds ratio [OR] 6.896, 95% CI 2.637 to 18.032, p <0.001), known coronary artery disease (OR 0.300, 95% CI 0.161 to 0.559, p <0.001), and age (OR 0.977, 95% CI 0.954 to 1.000, p = 0.050) independently predicted significant clinical change. In conclusion, stress CMR made a significant impact on clinical management, resulting in active change in clinical care in about 70% of patients. AUC categories were not an independent predictor of clinical change. Clinical change was independently associated with the presence of ischemia, absence of known coronary artery disease, and younger age.

Downstream clinical consequences of stress cardiovascular magnetic resonance based on appropriate use criteria.

BACKGROUND: Appropriate use criteria (AUC) have been developed by professional organizations as a response to the rising costs of imaging, with the goal of optimizing test-patient selection. Consequently, the AUC are now increasingly used by third-party-payers to assess reimbursement. However, these criteria were created by expert consensus and have not been systematically assessed for CMR. The aim of this study was to determine the rates of abnormal stress-CMR and subsequent downstream utilization of angiography and revascularization procedures based on the most recent AUC. METHODS: 300 consecutive patients referred for CMR-stress testing were prospectively enrolled. Two cardiologists reviewed all clinical information before the CMR-stress test and classified the test as "appropriate', "maybe appropriate" or "rarely appropriate" according to the 2013 AUC. Patients were followed for 2 months for the primary outcomes of coronary angiography and/or revascularization. RESULTS: 49.7% of stress CMRs were appropriate, 36.7% maybe appropriate, and 13.6% rarely appropriate. Ischemia was significantly more likely to be seen in the appropriate (18.8%) or maybe appropriate groups (21.8%) than the rarely appropriate group (4.8%) (p = 0.030 and p = 0.014 respectively). Referral for cardiac catheterization was not significantly different in the appropriate (10.1%) and maybe appropriate groups (10.0%) compared to the rarely appropriate group (2.4%) (p = 0.119 and p = 0.127 respectively). No patients undergoing catheterization in the rarely appropriate group went on to require revascularization, in contrast to 53.3% of the appropriate vs 36.4% of the maybe appropriate patients (p = 0.391). Presence of ischemia led to referral for cardiac catheterization in 50.0% of the appropriate group vs 33.3% of the maybe appropriate group (p = 0.225); in contrast to none of the rarely appropriate group. CONCLUSIONS: The great majority of tests were classified as appropriate or maybe appropriate. Downstream cardiac catheterization rates were similar in all 3 groups. However, rarely appropriate studies never required revascularization, suggesting suboptimal resource utilization. Studies classified as maybe appropriate had similar rates of abnormal findings and led to similar rates of downstream catheterization and revascularization as those that were deemed appropriate. This suggests that consideration could be given to upgrading some of the common maybe appropriate indications to the appropriate category.

Assessment of global myocardial perfusion reserve using cardiovascular magnetic resonance of coronary sinus flow at 3 Tesla.

BACKGROUND: Despite increasing clinical use, there is limited data regarding regadenoson in stress perfusion cardiovascular magnetic resonance (CMR). In particular, given its long half-life the optimal stress protocol remains unclear. Although Myocardial Perfusion Reserve (MPR) may provide additive prognostic information, current techniques for its measurement are cumbersome and challenging for routine clinical practice.The aims of this study were: 1) To determine the feasibility of MPR quantification during regadenoson stress CMR by measurement of Coronary Sinus (CS) flow; and 2) to investigate the role of aminophylline reversal during regadenoson stress-CMR. METHODS: 117 consecutive patients with possible myocardial ischemia were prospectively enrolled. Perfusion imaging was performed at 1 minute and 15 minutes after administration of 0.4 mg regadenoson. A subgroup of 41 patients was given aminophylline (100 mg) after stress images were acquired. CS flow was measured using phase-contrast imaging at baseline (pre CS flow), and immediately after the stress (peak CS flow) and rest (post CS flow) perfusion images. RESULTS: CS flow measurements were obtained in 92% of patients with no adverse events. MPR was significantly underestimated when calculated as peak CS flow/post CS flow as compared to peak CS flow/pre CS flow (2.43±0.20 vs. 3.28±0.32, p=0.03). This difference was abolished when aminophylline was administered (3.35±0.44 vs. 3.30±0.52, p=0.95). Impaired MPR (peak CS flow/pre CS flow<2) was associated with advanced age, diabetes, current smoking and higher Framingham risk score. CONCLUSIONS: Regadenoson stress CMR with MPR measurement from CS flow can be successfully performed in most patients. This measurement of MPR appears practical to perform in the clinical setting. Residual hyperemia is still present even 15 minutes after regadenoson administration, at the time of resting-perfusion acquisition, and is completely reversed by aminophylline. Our findings suggest routine aminophylline administration may be required when performing stress CMR with regadenoson.

Palpitations in a 64-year-old man.

A 64-year-old man presented with several weeks of intermittent irregular palpitations. He had no prior history of cardiac disease, hypertension or syncope. A 12-lead ECG revealed sinus rhythm with premature atrial and ventricular contractions and high QRS voltages consistent with LV-hypertrophy. Cardiac MR revealed asymmetrical septal hypertrophy and marked mid-myocardial hyperenhancement of the interventricular septum.

Left ventricular hypertrophy: an overlooked cardiovascular risk factor.

Left ventricular hypertrophy (LVH) is common in hypertensive patients, and it increases the risk of myocardial infarction, stroke, and death. Recent evidence indicates it is a modifiable risk factor that is not entirely dependent on blood pressure control. The authors review its pathogenesis, diagnosis, and treatment.