To assess the feasibility of feature tracking (FT)-measured systolic strain post acute ST-segment elevation myocardial infarction (STEMI) and compare strain values to those obtained with tagging. Cardiovascular MRI at 1.5T was performed in 24 patients, 2.2 days post STEMI. Global and segmental circumferential (Ecc) and longitudinal (Ell) strain were assessed using FT and tagging, and correlated with total and segmental infarct size, area at risk and myocardial salvage. All segments tracked satisfactorily with FT (p0.7) apart from tagging Ell, which was poor (ICC=0.15). FT-derived Ecc significantly correlated with total infarct size (r=0.44, p=0.03) and segmental infarct extent (r=0.44, p<0.01), and best distinguished transmurally infarcted segments (AUC 0.77) and infarcted from adjacent and remote segments. FT-derived Ecc correlated strongest with segmental myocardial salvage (rs=-0.406). FT global Ecc and Ell measurement in acute STEMI is feasible and robust. FT-derived strain is quicker to analyse, tracks myocardium better, has better interobserver variability and correlated more strongly with infarct, area at risk (oedema), myocardial salvage and infarct transmurality.
To assess cardiovascular magnetic resonance (CMR) measured myocardial perfusion reserve (MPR) and exercise testing in asymptomatic patients with moderate-severe AS. Multi-centre, prospective, observational study, with blinded analysis of CMR data. Patients underwent adenosine stress CMR, symptom-limited exercise testing (ETT) and echocardiography and were followed up for 12–30 months. The primary outcome was a composite of: typical AS symptoms necessitating referral for AVR, cardiovascular death and major adverse cardiovascular events. 174 patients were recruited: mean age 66.2 ± 13.34 years, 76% male, peak velocity 3.86 ± 0.56 m/s and aortic valve area index 0.57 ± 0.14 cm2/m2. A primary outcome occurred in 47 (27%) patients over a median follow-up of 374 (IQR 351–498) days. The mean MPR in those with and without a primary outcome was 2.06 ± 0.65 and 2.34 ± 0.70 (P = 0.022), while the incidence of a symptom-limited ETT was 45.7% and 27.0% (P = 0.020), respectively. MPR showed moderate association with outcome area under curve (AUC) = 0.61 (0.52–0.71, P = 0.020), as did exercise testing (AUC = 0.59 (0.51–0.68, P = 0.027), with no significant difference between the two. MPR was associated with symptom-onset in initially asymptomatic patients with AS, but with moderate accuracy and was not superior to symptom-limited exercise testing. ClinicalTrials.gov (NCT01658345).
1 February 2018 in Journal of Cardiovascular Magnetic Resonance
Heart failure with preserved ejection fraction (HFpEF) is a poorly characterized condition. We aimed to phenotype patients with HFpEF using multiparametric stress cardiovascular magnetic resonance imaging (CMR) and to assess the relationship to clinical outcomes. One hundred and fifty four patients (51% male, mean age 72 ± 10 years) with a diagnosis of HFpEF underwent transthoracic echocardiography and CMR during a single study visit. The CMR protocol comprised cine, stress/rest perfusion and late gadolinium enhancement imaging on a 3T scanner. Follow-up outcome data (death and heart failure hospitalization) were captured after a minimum of 6 months. CMR detected previously undiagnosed pathology in 42 patients (27%), who had similar baseline characteristics to those without a new diagnosis. These diagnoses consisted of: coronary artery disease (n = 20, including 14 with ‘silent’ infarction), microvascular dysfunction (n = 11), probable or definite hypertrophic cardiomyopathy (n = 10) and constrictive pericarditis (n = 5). Four patients had dual pathology. During follow-up (median 623 days), patients with a new CMR diagnosis were at higher risk of adverse outcome for the composite endpoint (log rank test: p = 0.047). In multivariate Cox proportional hazards analysis, a new CMR diagnosis was the strongest independent predictor of adverse outcome (hazard ratio: 1.92; 95% CI: 1.07 to 3.45; p = 0.03). CMR diagnosed new significant pathology in 27% of patients with HFpEF. These patients were at increased risk of death and heart failure hospitalization. ClinicalTrials.gov Identifier: NCT03050593 . Retrospectively registered; Date of registration: February 06, 2017.
13 February 2015 in European Heart Journal - Cardiovascular Imaging
Aims (i) To establish the test–retest reproducibility of myocardial T1 and extracellular volume (ECV) fraction measurement in asymptomatic patients with moderate–severe aortic stenosis (AS), (ii) to compare reproducibility using motion-corrected (MOCO) parametric T1 maps for analysis vs . full MOLLI series of images, and (iii) to compare T1 and ECV between patients and age-matched controls. Methods and results 3 T cardiac MRI was performed twice on 10 patients (median interval 7 days) to assess reproducibility. An additional 40 patients and 22 asymptomatic controls underwent a single MRI. Native T1 and ECV were calculated by outlining the myocardium on T1 maps generated inline, and using an offline T1 fit on the MOCO multiple inversion-time raw image series, in the reproducibility cohort ( n = 10). Reproducibility was excellent using the inline T1 maps (CoVs for T1: 1.77%; ECV: 6.52%) and good using the full MOLLI series (CoVs for T1: 8.52%; ECV: 12.98%). On comparing AS and controls, who were well matched for age, gender and co-morbidities, there was no significant difference in the native T1 or ECV (T1 = 1103.32 ± 33.07 vs. 1092.27 ± 34.29; ECV = 0.243 ± 0.019 vs. 0.251 ± 0.026 in patients and controls, P > 0.05), which was maintained even after splitting the patients into moderate and severe AS subgroups. Conclusion The test–retest reproducibility of myocardial T1 quantification using MOLLI is excellent in patients with AS and is highest using inline generated T1 maps for analysis. There was no difference in native myocardial T1 or ECV between asymptomatic patients with moderate–severe AS and age-matched controls without valve disease.