Cardiac Magnetic Resonance in Stable Coronary Artery Disease: Added Prognostic Value to Conventional Risk Profiling.

AIMS: Cardiovascular magnetic resonance (CMR) permits a comprehensive evaluation of stable coronary artery disease (CAD). We sought to assess whether, in a large contemporaneous population receiving optimal medical therapy, CMR independently predicts prognosis beyond conventional cardiovascular risk factors (RF). METHODS: We performed a single centre, observational prospective study that enrolled 465 CAD patients (80% males; 63±11 years), optimally treated with ACE-inhibitors/ARB, aspirin, and statins (76-85%). Assessments included conventional evaluation (clinical history, atherosclerosis RF, electrocardiography, and echocardiography) and a comprehensive CMR with LV dimensions/function, late gadolinium enhancement (LGE), and stress perfusion CMR (SPCMR). RESULTS: During a median follow-up of 62 months (IQR 23-74) there were 50 deaths and 92 major adverse cardiovascular events (MACE). CMR variables improved multivariate model prediction power of mortality and MACE over traditional RF alone (F-test p<0.05 and p<0.001, respectively). LGE was an independent prognostic factor of mortality (hazard ratio [95% CI]: 3.4 [1.3-8.8]); moreover, LGE (3.3 [1.7-6.3]) and SPCMR (2.1 [1.4-3.2]) were the best predictors of MACE. CONCLUSION: LGE is an independent noninvasive marker of mortality in the long term in patients with stable CAD and optimized medical therapy. Furthermore, LGE and SPCMR independently predict MACE beyond conventional risk stratification.

Late gadolinium enhancement by cardiovascular magnetic resonance is complementary to left ventricle ejection fraction in predicting prognosis of patients with stable coronary artery disease.

BACKGROUND: Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) predicts adverse prognosis in patients with stable coronary artery disease (CAD). However, the interaction with conventional risk factors remains uncertain. Our aim was to assess whether the extent of LGE is an independent predictor of adverse cardiac outcome beyond conventional risk factors, including left ventricle ejection fraction (LVEF). METHODS: We enrolled 376 patients (88% males, 64 ± 11 years) with stable CAD, who underwent LGE assessment and a detailed conventional evaluation (clinical and pharmacological history, risk factors, ECG, Echocardiography). During a follow-up of 38 ± 21 months, 56 events occurred (32 deaths, 24 hospitalizations for heart failure). RESULTS: LGE and LVEF showed the strongest univariate associations with end-points (HR: 13.61 [95%C.I.: 7.32-25.31] for LGE ≥ 45% of LV mass; and 12.34 [6.80-22.38] for LVEF ≤ 30%; p < 0.0001). Multivariate analysis identified baseline LVEF, loop diuretic therapy, moderate-severe mitral regurgitation and pulmonary hypertension as significant predictors among conventional risk factors. According to a step-wise approach, LGE showed strong association with prognosis as well (5.25 [2.64-10.43]; p < 0.0001). LGE significantly improved the model predictability (chi-square 239 vs 221, F-test p < 0.0001) with an additive effect on the prognostic power of LVEF, which however retained its prognostic power (4.89 [2.50-09.56]; p < 0.0001). Patients with LGE ≥ 45% and/or LVEF ≤ 30% had much worse prognosis compared to patients without risk factors (annual event rates of 43% vs 3%; p < 0.0001). Interestingly LGE was a significant predictor when all cause mortality was analyzed as the only endpoint. CONCLUSIONS: This study demonstrates that LGE assessed by CMR is a robust independent non-invasive marker of prognosis in stable CAD patients. LGE can integrate the available metrics to substantially improve risk stratification.

Intra-observer and interobserver reproducibility of right ventricle volumes, function and mass by cardiac magnetic resonance.

OBJECTIVES: Cardiac magnetic resonance (CMR) allows quick and non-invasive evaluation both of right ventricle (RV) volume and function, which are important in many heart diseases. We have evaluated CMR intra- and interobserver reproducibility in different conditions of RV dimension and function. METHODS: We have analysed CMR exams of 45 subjects, randomly selected from our database according to RV end-diastolic volume (EDV; 15-subject groups with EDV < 25th, 25-75th and > 75th percentiles of a normal control population). Selected subjects were of both sexes (male/female 33/12) and of variable age (8-83 years) and body surface (0.9-2.3 m). RV end-diastolic and end-systolic volumes (ESV), ejection fraction (EF) and mass were blindly evaluated by two operators. Bland-Altman bias and coefficient of variability (CoV) were used to assess intra- and interobserver reproducibility. RESULTS: A wide range of EDV (range = 46-239 ml), ESV (20-129 ml) and EF (6-64%) was observed. The intra-observer bias was -5 ml for EDV, -2 ml for ESV, -1% for EF and 5 g for mass, with a CoV of 7-12%. The interobserver bias was 5 ml for EDV, 2 ml for ESV, 2% for EF and 6 g for mass, with a CoV of 8-13%. Analysis by tertiles showed EF assessment variability to be higher in the lower tertiles at intra-observer (P < 0.036) and, above all, at interobserver (P < 0.000) analysis. Mass assessment variability was higher in the upper tertile (P < 0.004) at intra-observer analysis. CONCLUSIONS: Intra- and interobserver reproducibility of RV parameters assessed by CMR are adequate in a wide range of RV dimensions and function. However, caution is required with respect to the significance of small changes of EF and mass in the case of poor function and hypertrophy of the RV, respectively.

Scar detection by contrast-enhanced magnetic resonance imaging in chronic coronary artery disease: a comparison with nuclear imaging and echocardiography.

We compared contrast-enhanced MRI (CeMRI) with the most widely used imaging techniques for myocardial infarct (MI) diagnosis, SPECT and Echo, in unselected patients with chronic coronary artery disease (CAD). Two blinded operators assessed scars on MRI, SPECT and Echo images using a 16-segments LV model. We studied 105 consecutive patients: 50 had Q-wave MI (Q-MI), 19 non Q-wave MI or rest angina (nonQ-MI/RA) and 36 effort angina (EA) history. CeMRI was positive, respectively, in 96%, 37%, and 6%, SPECT in 90%, 53%, and 44%, and Echo in 84%, 32%, and 28% of patients (within Q-MI: CeMRI vs. SPECT p < 0.03, vs. Echo p < 0.001; within EA CeMRI vs. SPECT and ECHO p < 0.001; all trends p < 0.001, pseudo r-square: 0.56-0.75 for CeMRI, 0.18-0.28 for SPECT and 0.23-0.37 for Echo). CeMRI and SPECT agreed in 83 patients (79%); negative SPECT with 1 +/- 0 segments subendocardial delayed enhancement (DE) was found in 4 (4%); negative CeMRI with 4 +/- 3 segments perfusion defects in 18 (17%), 16 of whom were obese or showed LBB or sub-occlusion of related coronary. CeMRI and Echo agreed in 78 patients (75%); negative Echo with 2 +/- 1 segments subendocardial DE was found in 13 (12%) and negative CeMRI with 11 +/- 7 segments kinetic abnormalities in 14 (13%), in 10 confirmed by Cine-MRI. In Q-MI, CeMRI detects DE more frequently than perfusion defects and, especially, kinetic abnormalities are found by SPECT and Echo, respectively. CeMRI identifies small areas of DE also in some patients with nonQ-MI or RA but usually not in patients with EA. This biologically plausible decreasing trend is shown by CeMRI more clearly than by SPECT and Echo. Disagreement between CeMRI and SPECT or Echo may be reduced, but perhaps not fully eluded, performing dobutamine Echo and SPECT after maximal epicardial coronary dilatation.