Association of left atrial size and function by cardiac magnetic resonance imaging with long term outcomes in patients with hypertrophic cardiomyopathy.

Left atrial (LA) function and strain are being investigated as markers of disease progression in hypertrophic cardiomyopathy (HCM). To assess LA function and strain by cardiac magnetic resonance imaging (MRI) in patients with HCM and evaluate the association of these parameters with long-term clinical outcomes. We retrospectively evaluated 50 HCM patients and 50 patients with no significant cardiovascular disease (control) who underwent clinically indicated cardiac MRI. We calculated LA volumes using the Simpson area-length method to derive LA ejection fraction and expansion index. MRI-derived left atrial reservoir (ƐR), conduit (ƐCD), and contractile strain (ƐCT) were measured using dedicated software. A multivariate regression analysis with endpoints of ventricular tachyarrhythmias (VTA) and heart failure hospitalization (HFH) was performed. HCM patients had significantly higher LV mass, higher LA volumes and lower LA strain compared to controls. During the median follow up of 15.6 months (interquartile range 8.4-35.4 months), 11 patients (22%) experienced a HFH, while 10 patients (20%) had VTA. Multivariate analysis demonstrated that ƐCT (odds ratio (OR) 0.96, confidence interval (CI) 0.83-1.00) and LA ejection fraction (OR 0.89, CI 0.79-1.00) were significantly associated with VTA and HFH respectively.

Association of Left Atrial Hemodynamics by Magnetic Resonance Imaging With Long-Term Outcomes in Patients With Cardiac Amyloidosis.

BACKGROUND: Left atrial (LA) function and strain patterns by magnetic resonance imaging (MRI) have been investigated as markers of several cardiovascular pathologies, including cardiac amyloidosis (CA). However, associations with clinical outcomes have not been investigated. PURPOSE: To compare LA function and strain by MRI in CA patients to a matched cohort of patients without cardiovascular disease (CVD) and evaluate the association with long-term clinical outcomes in CA patients. STUDY TYPE: Retrospective case control. POPULATION: A total of 51 patients with CA and 51 age-, gender-, and race-matched controls without CVD who underwent MRI in sinus rhythm. FIELD STRENGTH/SEQUENCE: ECG-gated balanced steady-state free precession sequence at 1.5 T. ASSESSMENT: All measurements were completed by one investigator (M.M.B.). LA function and strain parameters were measured including LA indexed minimum and maximum volumes, LA reservoir (R), contractile (CT), and conduit (CD) strain. We compared groups after adjusting for age, hypertension, New York Heart Association class, modified staging system (troponin-I, BNP, estimated GFR) and left ventricular ejection fraction (LVEF) for an endpoint of all-cause mortality and a composite endpoint of heart failure hospitalization (HFH) or death. STATISTICAL TESTS: Differences between groups were evaluated with t tests for continuous variables or χ2 tests for categorical variables. A multivariable regression model was used to assess the associations of the P values-two-sided tests-<0.05 were considered statistically significant. RESULTS: CA patients with median follow up of 4.9 (8.5) months had significantly lower LA strain and higher LA volumes in comparison to the matched cohort. In the multivariable analysis, only LVEF was significantly associated with death while ƐCT (OR 0.6, CI: 0.41-0.89), indexed minimum LA volume (OR 1.06, CI: 1.02-1.13) and indexed maximum LA volume (OR 1.08, CI: 1.01-1.15) were significantly associated with the composite outcome of death or HFH. CONCLUSION: In this retrospective study of CA patients, ƐCT and indexed minimum and maximum LA volumes were significantly associated with the composite outcome of death or HFH. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 3.

Comparison of LGE quantitation methods in cardiac sarcoidosis to predict clinical outcomes.

We sought to investigate the optimal method of quantifying late gadolinium enhancement (LGE) in cardiac sarcoidosis (CS) using cardiac magnetic resonance imaging (MRI). We retrospectively studied 53 patients with CS. LGE quantitation was performed using (a) semi-automated segmentation using Signal Threshold versus Reference Mean (STRM) cutoffs of > 2, > 3 and > 5 standard deviations (SD); (b) full-width-half-max (FWHM) method and (c) manual segmentation (MS) of affected myocardial segments. Primary outcome was a composite of cardiovascular death and ventricular tachyarrhythmia (VTA). A multivariate regression analysis was performed comparing the techniques adjusting for age, gender, NYHA class and LVEF. Mean age was 56.3 ± 12 years, 71.6% males, 66% white. Mean LVEF was 45.1% ± 14.7%. Over median follow-up of 28.1 months, 2 patients had cardiac death (3.7%) and 8 (15.1%) had VTA. On multivariate analysis, MS, > 2SD, > 3SD, > 5SD and FWHM had OR of 1.39 [CI 1.04-1.79], 1.09 [CI 0.99-1.21], 1.15 [CI 1.03-1.29], 1.16 [CI 1.04-1.27] and 1.08 [CI 0.96-1.21], respectively, for predicting the composite outcome. ROC curve analysis showed MS to have the highest AUC 0.89 followed by 0.81 for > 3SD and > 5SD, 0.75 for > 2SD and lowest 0.69 for FWHM method. Reproducibility was lower for manual method (ICC 0.7) than for > 3SD (ICC 0.991) and > 5SD (ICC 0.997). CS quantitation of LGE with MS or semi-automated quantitation with STRM > 3SD or > 5SD was significantly associated with the composite outcome of cardiac death and VTA. Semi-automated quantitation with STRM > 3SD provided the best combination of accuracy and reproducibility.

Comparison of left atrial strain by feature-tracking cardiac magnetic resonance with speckle-tracking transthoracic echocardiography.

Left atrial (LA) strain is a novel non-invasive parameter for assessing LA hemodynamics and function. We sought to compare the intermodality differences between transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) derived LA strain, as well as reproducibility of strain measurements. We evaluated 70 subjects (mean age 42.1 ± 17 years, 44% males) with no significant cardiovascular disease who underwent both CMR and TTE within 6 months of each other. LA strain measurements i.e. reservoir strain (ƐR), conduit strain (ƐCD), and contractile strain (ƐCT), were compared using speckle-tracking echocardiography (STE) and CMR feature tracking (CMR-FT). Correlation and systematic bias between modalities was evaluated using intraclass correlation coefficient (ICC) and proportional bias. TTE was performed before CMR with a median duration of 33 days (IQR 14-69 days). ICC for ƐR, ƐCT, ƐCD was 0.66 (95% CI 0.44-0.79), 0.63 (95% CI 0.4-0.77) and 0.56 (95% CI 0.3-0.73) respectively. There was evidence of systematic bias between modalities, on average LA volume was found to be 19% higher on CMR than TTE. Strain values were also higher by CMR-FT compared to STE with mean difference of 9.9 ± 12 (26.1%), 3.1 ± 5.5 (21.9%), 4.0 ± 9.9 (16.6%) for ƐR, ƐCT and ƐCD respectively. Regression showed proportional bias for both ƐR, and ƐCT (beta 0.76, 0.54 respectively; P < 0.0001). There were modest differences in intraobserver reproducibility between both modalities with better reproducibility for STE compared to CMR-FT. There was a modest intermodality correlation between STE and CMR-FT derived LA strain components. There were systematic differences and proportional bias in measurements between modalities. These differences should be considered when interpreting LA strain using either modality.

The association of 9p21-3 locus with coronary atherosclerosis: a systematic review and meta-analysis.

BACKGROUND: Studies suggest that the 9p21-3 locus may influence susceptibility to myocardial infarction. We performed a systematic review and meta-analysis to assess whether this locus is associated with severity of coronary atherosclerosis and adverse clinical outcomes in those with known coronary disease. METHODS: Multiple electronic databases were searched from inception through August 2012. Studies examining 9p21-3 genotype in patients with known coronary artery disease were included. We extracted the association of the 9p21-3 locus with measures of severity of coronary atherosclerosis [number of diseased vessels, Gensini Score, Duke CAD Prognostic Index (DPI)], angiographic outcomes [change in minimum lumen diameter (∆MLD) and number of new lesions at follow-up], and key clinical outcomes (all-cause mortality, recurrent myocardial infarction and the need for coronary revascularization). Relative risks (RR) and weighted mean difference (WMD) were pooled using the random effects models. RESULTS: 23 cohorts enrolling 16,860 participants were analyzed. There was no significant difference between HR and LR genotypes in terms of all-cause mortality, recurrent myocardial infarction or the frequency of coronary revascularization. HR genotype was associated with increased risk of triple vessel disease (RR = 1.34; 95% CI 1.08-1.65; P = 0.01) and increased baseline Gensini Score (WMD = 5.30; 95% CI 0.66-9.93; P = 0.03). However there was no association with DPI (WMD = 4.00; 95% CI 2.94-10.94; P = 0.26). HR genotype did not predict ∆MLD or number of new lesions at follow-up. CONCLUSIONS: Patients of coronary atherosclerosis who carry the high risk genotype of the 9p21-3 allele may be more likely to have multi-vessel CAD. However the effect of this allele on CAD progression and disease specific clinical outcomes are not observed possibly due to diminishing genetic risk following dietary modification and therapy.