Anvesha Singh

Intertechnique agreement and interstudy reproducibility of strain and diastolic strain rate at 1.5 and 3 Tesla: a comparison of feature-tracking and tagging in patients with aortic stenosis.

To determine the interstudy reproducibility of myocardial strain and peak early‐diastolic strain rate (PEDSR) measurement on cardiovascular magnetic resonance imaging (MRI) assessed with feature tracking (FT) and tagging, in patients with aortic stenosis (AS).

Comparison of cardiovascular magnetic resonance feature tracking and tagging for the assessment of left ventricular systolic strain in acute myocardial infarction

AIMS 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. METHODS 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. RESULTS All segments tracked satisfactorily with FT (p<0.001 vs. tagging). Total analysis time per patient was shorter with FT (38.2±3.8 min vs. 63.7±10.3 min, p<0.001 vs. tagging). Global Ecc and Ell were higher with FT than with tagging, apart from FT Ecc using the average of endocardial and epicardial contours (-13.45±4.1 [FT] vs. -13.85±3.9 [tagging], p=0.66). Intraobserver and interobserver agreement for global strain were excellent for FT (ICC 0.906-0.990) but interobserver agreement for tagging was lower (ICC<0.765). Interobserver and intraobserver agreement for segmental strain was good for both techniques (ICC>0.7) 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). CONCLUSIONS 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.

Myocardial T1 and extracellular volume fraction measurement in asymptomatic patients with aortic stenosis: reproducibility and comparison with age-matched controls

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.

Subclinical diastolic dysfunction in young adults with Type 2 diabetes mellitus: a multiparametric contrast-enhanced cardiovascular magnetic resonance pilot study assessing potential mechanisms

AIMS To assess the cardiac, vascular, anthropometric, and biochemical determinants of subclinical diastolic dysfunction in younger adults with Type 2 diabetes mellitus (T2DM) using multiparametric contrast-enhanced cardiovascular magnetic resonance (CMR) imaging. METHODS AND RESULTS Twenty adults <40 years with T2DM [mean age 31.8(6.6) years, T2DM duration 4.7(4.0) years] and 20 age and sex-matched controls [10 obese non-diabetic controls and 10 lean controls (LC)] were studied. Cardiac volumes and function, circumferential strain and peak early diastolic strain rate (PEDSR), myocardial perfusion reserve, aortic stiffness (distensibility, pulse-wave velocity), focal fibrosis on late gadolinium enhancement, and pre- and post-contrast T1 mapping for contrast agent partition coefficient (subset, n = 26) were determined by CMR. In the T2DM cohort, mean aortic distensibility correlated with PEDSR (r = 0.564, P = 0.023) and diabetes duration correlated inversely with PEDSR (r = -0.534, P = 0.015) on univariate analysis. There was a close association between PEDSR and peak systolic strain (r = -0.580, P = 0.007). CONCLUSION In young adults with T2DM, diabetes duration and aortic distensibility were associated with diastolic dysfunction. Interventional studies are required to assess whether cardiac dysfunction can be reversed in this phenotype of patients.

Type 2 diabetes mellitus and obesity in young adults: the extreme phenotype with early cardiovascular dysfunction.

A pilot study to phenotype young adults (< 40 years) with Type 2 diabetes mellitus.

Rationale and design of the PRognostic Importance of MIcrovascular Dysfunction in asymptomatic patients with Aortic Stenosis (PRIMID-AS): a multicentre observational study with blinded investigations.

Introduction Aortic stenosis (AS) is the commonest valve disorder in the developed world requiring surgery. Surgery in patients with severe asymptomatic AS remains controversial. Exercise testing can identify asymptomatic patients at increased risk of death and symptom development, but with limited specificity, especially in older adults. Cardiac MRI (CMR), including myocardial perfusion reserve (MPR) may be a novel imaging biomarker in AS. Aims (1) To improve risk stratification in asymptomatic patients with AS and (2) to determine whether MPR is a better predictor of outcome than exercise testing and brain natriuretic peptide (BNP). Method/design Multicentre, prospective observational study in the UK, comparing MPR with exercise testing and BNP (with blinded CMR analysis) for predicting outcome. Population 170 asymptomatic patients with moderate-to-severe AS, who would be considered for aortic valve replacement (AVR). Primary outcome Composite of: typical symptoms necessitating referral for AVR and major adverse cardiovascular events. Follow-up: 12–30 months (minimum 12 months). Primary hypothesis MPR will be a better predictor of outcome than exercise testing and BNP. Ethics/dissemination The study has full ethical approval and is actively recruiting patients. Data collection will be completed in November 2014 and the study results will be submitted for publication within 6 months of completion. ClinicalTrials.gov identifier NCT01658345.

Comparison of exercise testing and CMR measured myocardial perfusion reserve for predicting outcome in asymptomatic aortic stenosis: the PRognostic Importance of MIcrovascular Dysfunction in Aortic Stenosis (PRIMID AS) Study

Aims To assess cardiovascular magnetic resonance (CMR) measured myocardial perfusion reserve (MPR) and exercise testing in asymptomatic patients with moderate-severe AS. Methods and results 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. Conclusions 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).

Comparison of semi-automated methods to quantify infarct size and area at risk by cardiovascular magnetic resonance imaging at 1.5T and 3.0T field strengths.

BackgroundThere is currently no gold standard technique for quantifying infarct size (IS) and ischaemic area-at-risk (AAR [oedema]) on late gadolinium enhancement imaging (LGE) and T2-weighted short tau inversion recovery imaging (T2w-STIR) respectively. This study aimed to compare the accuracy and reproducibility of IS and AAR quantification on LGE and T2w-STIR imaging using Otsu’s Automated Technique (OAT) with currently used methods at 1.5T and 3.0T post acute ST-segment elevation myocardial infarction (STEMI).MethodsTen patients were assessed at 1.5T and 10 at 3.0T. IS was assessed on LGE using 5–8 standard-deviation thresholding (5-8SD), full-width half-maximum (FWHM) quantification and OAT. AAR was assessed on T2w-STIR using 2SD and OAT. Accuracy was assessed by comparison with manual quantification. Interobserver and intraobserver variabilities were assessed using Intraclass Correlation Coefficients and Bland-Altman analysis. IS using each technique was correlated with left ventricular ejection fraction (LVEF).ResultsFWHM and 8SD-derived IS closely correlated with manual assessment at both field strengths (1.5T: 18.3 ± 10.7% LV Mass [LVM] with FWHM, 17.7 ± 14.4% LVM with 8SD, 16.5 ± 10.3% LVM with manual quantification; 3.0T: 10.8 ± 8.2% LVM with FWHM, 11.4 ± 9.0% LVM with 8SD, 11.5 ± 9.0% LVM with manual quantification). 5SD and OAT overestimated IS at both field strengths. OAT, 2SD and manually quantified AAR closely correlated at 1.5T, but OAT overestimated AAR compared with manual assessment at 3.0T. IS and AAR derived by FWHM and OAT respectively had better reproducibility compared with manual and SD-based quantification. FWHM IS correlated strongest with LVEF.ConclusionsFWHM quantification of IS is accurate, reproducible and correlates strongly with LVEF, whereas 5SD and OAT overestimate IS. OAT accurately assesses AAR at 1.5T and with excellent reproducibility. OAT overestimated AAR at 3.0T and thus cannot be recommended as the preferred method for AAR quantification at 3.0T.

Relationship of Myocardial Strain and Markers of Myocardial Injury to Predict Segmental Recovery After Acute ST-Segment–Elevation Myocardial Infarction

Background—Late gadolinium-enhanced cardiovascular magnetic resonance imaging overestimates infarct size and underestimates recovery of dysfunctional segments acutely post ST-segment–elevation myocardial infarction. We assessed whether cardiovascular magnetic resonance imaging–derived segmental myocardial strain and markers of myocardial injury could improve the accuracy of late gadolinium-enhancement in predicting functional recovery after ST-segment–elevation myocardial infarction. Methods and Results—A total of 164 ST-segment–elevation myocardial infarction patients underwent acute (median 3 days) and follow-up (median 9.4 months) cardiovascular magnetic resonance imaging. Wall-motion scoring, feature tracking–derived circumferential strain (Ecc), segmental area of late gadolinium-enhancement (SEE), microvascular obstruction, intramyocardial hemorrhage, and salvage index (MSI) were assessed in 2624 segments. We used logistic regression analysis to identify markers that predict segmental recovery. At acute CMR 32% of segments were dysfunctional, and at follow-up CMR 19% were dysfunctional. Segmental function at acute imaging and odds ratio (OR) for functional recovery decreased with increasing SEE, although 33% of dysfunctional segments with SEE 76% to 100% improved. SEE was a strong predictor of functional improvement and normalization (area under the curve [AUC], 0.840 [95% confidence interval {CI}, 0.814–0.867]; OR, 0.97 [95% CI, 0.97–0.98] per +1% SEE for improvement and AUC, 0.887 [95% CI, 0.865–0.909]; OR, 0.95 [95% CI, 0.94–0.96] per +1% SEE for normalization). Its predictive accuracy for improvement, as assessed by areas under the receiver operator curves, was similar to that of MSI (AUC, 0.840 [95% CI, 0.809–0.872]; OR, 1.03 [95% CI, 1.02–1.03] per +1% MSI for improvement and AUC, 0.862 [0.832–0.891]; OR, 1.04 [95% CI, 1.03–1.04] per +1% SEE for normalization) and Ecc (AUC, 0.834 [95% CI, 0.807–0.862]; OR, 1.05 [95% CI, 1.03–1.07] per +1% MSI for improvement and AUC, 0.844 [95% CI, 0.818–0.871]; OR, 1.07 [95% CI, 1.05–1.10] per +1% SEE for normalization), and for normalization was greater than the other predictors. MSI and Ecc remained as significant after adjustment for SEE but provided no significant increase in predictive accuracy for improvement and normalization compared with SEE alone. MSI had similar predictive accuracy to SEE for functional recovery but was not assessable in 25% of patients. Microvascular obstruction provided no incremental predictive accuracy above SEE. Conclusions—This multicenter study confirms that SEE is a strong predictor of functional improvement post ST-segment–elevation myocardial infarction, but recovery occurs in a substantial proportion of dysfunctional segments with SEE >75%. Feature tracking–derived Ecc and MSI provide minimal incremental benefit to SEE in predicting segmental recovery. Clinical Trial Registration—URL: http://www.isrctn.com. Unique identifier: ISRCTN70913605.

Myocardial Perfusion Reserve but not fibrosis predicts outcomes in initially asymptomatic patients with moderate to severe aortic stenosis: the PRognostic Importance of MIcrovascular Dysfunction in AS study- PRIMID AS

Myocardial Perfusion Reserve but not fibrosis predicts outcomes in initially asymptomatic patients with moderate to severe aortic stenosis: the PRognostic Importance of MIcrovascular Dysfunction in AS studyPRIMID AS Anvesha Singh, Michael Jerosch-Herold, John P Greenwood, Colin Berry, Dana K Dawson, Chim C Lang, Damian J Kelly, David Sprigings, Jeffrey P Khoo, Kai Hogrefe, Richard P Steeds, Vijay Anand Dhakshinamurthy, Gerry P McCann