Basic Principles of the Echocardiographic Evaluation of Mitral Regurgitation

Mitral regurgitation (MR) is a common form of valvular heart disease that is associated with significant morbidity and mortality. Treatment decisions are completely dependent on accurate diagnosis of both mechanism and severity of MR, which can be challenging and is often done incorrectly. Transthoracic echocardiography is the most commonly used imaging test for MR; transesophageal echocardiography is often needed to better define morphology and MR severity, and is essential for guiding transcatheter therapies for MR. Multidetector computed tomography has become the standard to assess whether transcatheter valve replacement is an option because of its ability to assess valve sizing, access, and potential left ventricular outflow tract obstruction. Finally, cine cardiac magnetic resonance has been recommended by recent guidelines to quantify MR severity when the distinction between moderate and severe MR is indeterminate by echocardiography. This paper focuses on the main questions to be answered by imaging techniques and illustrates some common tips, tricks, and pitfalls in the assessment of MR.     

Longitudinal 2‐point dixon muscle magnetic resonance imaging in becker muscular dystrophy

Introduction: Quantitative MRI techniques detect disease progression in myopathies more sensitively than muscle function measures or conventional MRI. To date, only conventional MRI data using visual rating scales are available for measurement of disease progression in Becker muscular dystrophy (BMD). Methods: In 3 patients with BMD (mean age 36.8 years), the mean fat fraction (MFF) of the thigh muscles was assessed by MRI at baseline and at 1‐year follow‐up using a 2‐point Dixon approach (2PD). The motor function measurement scale (MFM) was used for clinical assessment. Results: The mean MFF of all muscles at baseline was 61.6% (SD 7.6). It increased by 3.7% to 65.3% (SD 4.7) at follow‐up. The severity of muscle involvement varied between various muscle groups. Conclusions: As in other myopathies, 2PD can quantify fatty muscle degeneration in BMD and can detect disease progression in a small sample size and at relatively short imaging intervals. Muscle Nerve 51 : 918–921, 2015     

Clinical Outcomes and Revascularization Strategies in Patients With Low-Flow,Low-Gradient Severe Aortic Valve Stenosis According to the Assigned Treatment Modality

ObjectivesThis study compared clinical outcomes and revascularization strategies among patients presenting with low ejection fraction, low-gradient (LEF-LG) severe aortic stenosis (AS) according to the assigned treatment modality.BackgroundThe optimal treatment modality for patients with LEF-LG severe AS and concomitant coronary artery disease (CAD) requiring revascularization is unknown.MethodsOf 1,551 patients, 204 with LEF-LG severe AS (aortic valve area <1.0 cm², ejection fraction <50%, and mean gradient <40 mm Hg) were allocated to medical therapy (MT) (n = 44), surgical aortic valve replacement (SAVR) (n = 52), or transcatheter aortic valve replacement (TAVR) (n = 108). CAD complexity was assessed using the SYNTAX score (SS) in 187 of 204 patients (92%). The primary endpoint was mortality at 1 year.ResultsLEF-LG severe AS patients undergoing SAVR were more likely to undergo complete revascularization (17 of 52, 35%) compared with TAVR (8 of 108, 8%) and MT (0 of 44, 0%) patients (p < 0.001). Compared with MT, both SAVR (adjusted hazard ratio [adj HR]: 0.16; 95% confidence interval [CI]: 0.07 to 0.38; p < 0.001) and TAVR (adj HR: 0.30; 95% CI: 0.18 to 0.52; p < 0.001) improved survival at 1 year. In TAVR and SAVR patients, CAD severity was associated with higher rates of cardiovascular death (no CAD: 12.2% vs. low SS [0 to 22], 15.3% vs. high SS [>22], 31.5%; p = 0.037) at 1 year. Compared with no CAD/complete revascularization, TAVR and SAVR patients undergoing incomplete revascularization had significantly higher 1-year cardiovascular death rates (adj HR: 2.80; 95% CI: 1.07 to 7.36; p = 0.037).ConclusionsAmong LEF-LG severe AS patients, SAVR and TAVR improved survival compared with MT. CAD severity was associated with worse outcomes and incomplete revascularization predicted 1-year cardiovascular mortality among TAVR and SAVR patients.     

Tricuspid Regurgitation Is Associated With Increased Risk of Mortality in Patients With Low-Flow Low-Gradient Aortic Stenosis and Reduced Ejection Fraction: Results of the Multicenter TOPAS Study (True or Pseudo-Severe Aortic Stenosis)

ObjectivesThis study sought to examine the impact of tricuspid regurgitation (TR) on mortality in patients with low-flow, low-gradient (LF-LG) aortic stenosis (AS) and reduced left ventricular ejection fraction (LVEF).BackgroundTR is often observed in patients with LF-LG AS and low LVEF, but its impact on prognosis remains unknown.MethodsA total of 211 patients (73 ± 10 years of age; 77% men) with LF-LG AS (mean gradient <40 mm Hg and indexed aortic valve area [AVA] ≤0.6 cm²/m²) and reduced LVEF (≤40%) were prospectively enrolled in the TOPAS (True or Pseudo-Severe Aortic Stenosis) study and 125 (59%) of them underwent aortic valve replacement (AVR) within 3 months following inclusion. The severity of AS was assessed by the projected AVA (AVA_proj) at normal flow rate (250 ml/s), as previously described and validated. The severity of TR was graded according to current guidelines.ResultsAmong the 211 patients included in the study, 22 (10%) had no TR, 113 (54%) had mild (grade 1), 50 (24%) mild-to-moderate (grade 2), and 26 (12%) moderate-to-severe (grade 3) or severe (grade 4) TR. During a mean follow-up of 2.4 ± 2.2 years, 104 patients (49%) died. Univariable analysis showed that TR ≥2 was associated with increased risk of all-cause mortality (hazard ratio [HR]: 1.82, 95% confidence interval [CI]: 1.22 to 2.71; p = 0.004) and cardiovascular mortality (HR: 1.85, 95% CI: 1.20 to 2.83; p = 0.005). After adjustment for age, sex, coronary artery disease, AVA_proj, LVEF, stroke volume index, right ventricular dysfunction, mitral regurgitation, and type of treatment (AVR vs. conservative), the presence of TR ≥2 was an independent predictor of all-cause mortality (HR: 1.88, 95% CI: 1.08 to 3.23; p = 0.02) and cardiovascular mortality (HR: 1.92, 95% CI: 1.05 to 3.51; p = 0.03). Furthermore, in patients undergoing AVR, TR ≥3 was an independent predictor of 30-day mortality compared with TR = 0/1 (odds ratio [OR]: 7.24, 95% CI: 1.56 to 38.2; p = 0.01) and TR = 2 (OR: 4.70, 95% CI: 1.00 to 25.90; p = 0.05).ConclusionsIn patients with LF-LG AS and reduced LVEF, TR is independently associated with increased risk of cumulative all-cause mortality and cardiovascular mortality regardless of the type of treatment. In patients undergoing AVR, moderate/severe TR is associated with increased 30-day mortality. Further studies are needed to determine whether TR is a risk marker or a risk factor of mortality and whether concomitant surgical correction of TR at the time of AVR might improve outcomes for this high-risk population.     

Baseline Characteristics and Prognostic Implications of Pre-Existing and New-Onset Atrial Fibrillation After Transcatheter Aortic Valve Implantation: Results From the FRANCE-2 Registry

ObjectivesThe aim of this study was to determine baseline characteristics and clinical outcomes of patients with pre-existing atrial fibrillation (AF) and of patients who presented with new-onset AF after transcatheter aortic valve implantation (TAVI).BackgroundLittle is known regarding the impact of AF after TAVI.MethodsThe FRANCE-2 registry included all patients undergoing TAVI (N = 3,933) in France in 2010 and 2011. New-onset AF was defined as the occurrence of AF post-procedure in a patient with no documented history of AF.ResultsAF was documented before TAVI in 25.8% of patients. New-onset AF was observed in 174 patients after TAVI among patients without a history of pre-existing AF (6.0%). At 1 year, the rates of all-cause death (26.5 vs. 16.6%, respectively; p < 0.001) and cardiovascular death (11.5 vs. 7.8%, respectively; p < 0.001) were significantly higher in patients with pre-existing AF compared with those without AF. Rehospitalization for worsening heart failure and New York Heart Association functional class was also higher in patients with pre-existing AF versus those without, resulting in a higher rate of combined efficacy endpoint in this group (p < 0.001). A history of stroke, surgical (nontransfemoral) approach, cardiological, and hemorrhagic procedure-related events were all independently related to the occurrence of new-onset post-procedural AF. New-onset AF in patients without pre-existing AF was associated with a higher rate of combined safety endpoint at 30 days (p < 0.001) and a higher rate of both all-cause death and combined efficacy endpoint at 1 year (p = 0.003 and p = 0.02, respectively).ConclusionsPre-existing and new-onset AF are both associated with higher mortality and morbidity after TAVI.     

Variant call concordance between two laboratory-developed,solid tumor targeted genomic profiling assays using distinct workflows and sequencing instruments

Targeted genomic profiling (TGP) using massively parallel DNA sequencing is becoming the standard methodology in clinical laboratories for detecting somatic variants in solid tumors. The variety of methodologies and sequencing platforms in the marketplace for TGP has resulted in a variety of clinical TGP laboratory developed tests (LDT). The variability of LDTs is a challenge for test-to-test and laboratory-to-laboratory reliability. At the University of Vermont Medical Center (UVMMC), we validated a TGP assay for solid tumors which utilizes DNA hybridization capture and complete exon and selected intron sequencing of 29 clinically actionable genes. The validation samples were run on the Illumina MiSeq platform. Clinical specificity and sensitivity were evaluated by testing samples harboring genomic variants previously identified in CLIA-approved, CAP accredited laboratories with clinically validated molecular assays. The Molecular Laboratory at Dartmouth Hitchcock Medical Center (DHMC) provided 11 FFPE specimens that had been analyzed on AmpliSeq Cancer Hotspot Panel version 2 (CHPv2) and run on the Ion Torrent PGM. A Venn diagram of the gene lists from the two institutions is shown. This provided an excellent opportunity to compare the inter-laboratory reliability using two different target sequencing methods and sequencing platforms. Our data demonstrated an exceptionally high level of concordance with respect to the sensitivity and specificity of the analyses. All clinically-actionable SNV and InDel variant calls in genes covered by both panels (n = 17) were identified by both laboratories. This data supports the proposal that distinct gene panel designs and sequencing workflows are capable of making consistent variant calls in solid tumor FFPE-derived samples.     

Circuit Life Versus Bleeding Risk: The Impact of Achieved Activated Partial Thromboplastin Time Versus Achieved Filtration Fraction

Whilst prolonging hemofilter (circuit) life, heparin increases bleeding risk. The impact of achieved activated partial thromboplastin time (APTT) on circuit life and bleeding risk has not been assessed in a modern critically ill cohort. Lowering filtration fraction may be an alternative means of prolonging circuit life, but is often overlooked in critical care. An observational study of 309 consecutive circuits in a general intensive care unit was conducted using a wide target APTT range. Multilevel modeling was used to predict circuit life and bleeding according to achieved APTT and filtration fraction. Independent predictors of circuit failure (i.e. unplanned ending of treatment) included filtration fraction (P < 0.001, HR 1.07 per 1% increase), peak APTT (P < 0.001, HR 0.8 per 10 s increase or 0.3 APTR increase) and baseline PT (P = 0.014, HR 0.91 for every 50% increase). The only significant predictor of bleeding was peak APTT (P = 0.017, OR 1.05 per 10 s increase). Every 10 s APTT increase was associated with a 20% reduction in circuit failure, but a 5% increase in hemorrhage. A 3% reduction in filtration fraction was associated with the same improvement in circuit life as a 10 s increase in APTT. Increasing APTT prolongs circuit life but carries a substantial risk of bleeding even in modern practice. Filtration fraction has a large impact on circuit life in the critically ill: a 3% reduction in filtration fraction, e.g. by increasing blood flow or delivering some of the clearance via dialysis, would be expected to reduce circuit failure as much as a 10 s increase in APTT.     

Estimating the age of healthy infants from quantitative myelin water fraction maps

The trajectory of the developing brain is characterized by a sequence of complex, nonlinear patterns that occur at systematic stages of maturation. Although significant prior neuroimaging research has shed light on these patterns, the challenge of accurately characterizing brain maturation, and identifying areas of accelerated or delayed development, remains. Altered brain development, particularly during the earliest stages of life, is believed to be associated with many neurological and neuropsychiatric disorders. In this work, we develop a framework to construct voxel‐wise estimates of brain age based on magnetic resonance imaging measures sensitive to myelin content. 198 myelin water fraction (VF_M) maps were acquired from healthy male and female infants and toddlers, 3 to 48 months of age, and used to train a sigmoidal‐based maturational model. The validity of the approach was then established by testing the model on 129 different VF_M datasets. Results revealed the approach to have high accuracy, with a mean absolute percent error of 13% in males and 14% in females, and high predictive ability, with correlation coefficients between estimated and true ages of 0.945 in males and 0.94 in females. This work represents a new approach toward mapping brain maturity, and may provide a more faithful staging of brain maturation in infants beyond chronological or gestation‐corrected age, allowing earlier identification of atypical regional brain development. Hum Brain Mapp 36:1233–1244, 2015. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc .