Whole exome and genome sequencing in mendelian disorders: a diagnostic and health economic analysis.

Whole genome sequencing (WGS) improves Mendelian disorder diagnosis over whole exome sequencing (WES); however, additional diagnostic yields and costs remain undefined. We investigated differences between diagnostic and cost outcomes of WGS and WES in a cohort with suspected Mendelian disorders. WGS was performed in 38 WES-negative families derived from a 64 family Mendelian cohort that previously underwent WES. For new WGS diagnoses, contemporary WES reanalysis determined whether variants were diagnosable by original WES or unique to WGS. Diagnostic rates were estimated for WES and WGS to simulate outcomes if both had been applied to the 64 families. Diagnostic costs were calculated for various genomic testing scenarios. WGS diagnosed 34% (13/38) of WES-negative families. However, contemporary WES reanalysis on average 2 years later would have diagnosed 18% (7/38 families) resulting in a WGS-specific diagnostic yield of 19% (6/31 remaining families). In WES-negative families, the incremental cost per additional diagnosis using WGS following WES reanalysis was AU$36,710 (£19,407;US$23,727) and WGS alone was AU$41,916 (£22,159;US$27,093) compared to WES-reanalysis. When we simulated the use of WGS alone as an initial genomic test, the incremental cost for each additional diagnosis was AU$29,708 (£15,705;US$19,201) whereas contemporary WES followed by WGS was AU$36,710 (£19,407;US$23,727) compared to contemporary WES. Our findings confirm that WGS is the optimal genomic test choice for maximal diagnosis in Mendelian disorders. However, accepting a small reduction in diagnostic yield, WES with subsequent reanalysis confers the lowest costs. Whether WES or WGS is utilised will depend on clinical scenario and local resourcing and availability.

Laboratory quality assessment of candidate gene panel testing for acute myeloid leukaemia: a joint ALLG / RCPAQAP initiative.

Accurate classification of acute myeloid leukaemia (AML) has become increasingly reliant on molecular characterisation of this blood cancer. Throughout Australia and New Zealand massively parallel sequencing (MPS) is being adopted by diagnostic laboratories for the routine evaluation of patients with AML. This technology enables the surveying of many genes simultaneously, with many technical advantages over single gene testing approaches. However, there are many variations in wet and dry lab MPS procedures, which raises the prospect of discordant results between laboratories. This study compared the results obtained from MPS testing of ten diagnostic AML bone marrow aspirate samples sent to eight participating laboratories across Australasia. A reassuringly high concordance of 94% was observed with regard to variant detection and characterisation of pathogenicity. The level of discordance observed, although low, demonstrates the need for ongoing assessment of concordance between diagnostic testing laboratories through quality assurance programs.

A multi-center randomized controlled trial to reduce unmet needs, depression, and anxiety among hematological cancer patients and their support persons.

Purpose: Individuals diagnosed with a high-grade hematological malignancy are at high risk for psychosocial distress. This study aimed to examine the effectiveness of a web-based information tool and nurse delivered telephone support in reducing: (i) unmet information needs; (ii) depression; and (iii) anxiety, among hematological cancer patients and their support persons (SPs).Methods: Patients with a new diagnosis of acute myeloid leukemia, acute lymphoblastic leukemia, Burkitt lymphoma, or lymphoblastic lymphoma and their SPs were enrolled in a prospective multi-site randomized trial. Participants received either access to an online information tool and telephone support from a hematology nurse, or usual care. Outcome data were collected 2, 4, 8, and 12 weeks post-recruitment. The primary endpoint was unmet information needs.Results: Data from 60 patients and 15 SPs were included in the analysis. There were no statistically significant differences in unmet information needs, depression or anxiety between intervention and control groups for patients. Patients in both groups demonstrated a decrease in information needs over the intervention period. Post hoc analyses revealed that patients who did not achieve remission with the first cycle of treatment experienced increased anxiety from 4 weeks until the end of the study (p = 0.008).Conclusions: A web-based information tool and nurse delivered telephone support did not reduce unmet information needs, depression or anxiety among hematological cancer patients, however this finding is inconclusive given the low power of the study.Implications for Psychosocial Providers or Policy: Patients who do not achieve remission are at high risk of anxiety, and may benefit from targeted psychological intervention.

Myocardial Scar But Not Ischemia Is Associated With Defibrillator Shocks and Sudden Cardiac Death in Stable Patients With Reduced Left Ventricular Ejection Fraction.

OBJECTIVES: This study sought to investigate the association of myocardial scar and ischemia with major arrhythmic events (MAEs) in patients with left ventricular ejection fraction (LVEF) ≤35%. BACKGROUND: Although myocardial scar is a known substrate for ventricular arrhythmias, the association of myocardial ischemia with ventricular arrhythmias in stable patients with left ventricular dysfunction is less clear. METHODS: A total of 439 consecutive patients (median age, 70 years; 78% male; 55% with implantable cardioverter defibrillator [ICD]) referred for stress/rest positron emission tomography (PET) and resting LVEF ≤35% were included. Primary outcome was time-to-first MAE defined as sudden cardiac death, resuscitated sudden cardiac death, or appropriate ICD shocks for ventricular tachyarrhythmias ascertained by blinded adjudication of hospital records, Social Security Administration's Death Masterfile, National Death Index, and ICD vendor databases. RESULTS: Ninety-one MAEs including 20 sudden cardiac deaths occurred in 75 (17%) patients during a median follow-up of 3.2 years. Transmural myocardial scar was strongly associated with MAEs beyond age, sex, cardiovascular risk factors, beta-blocker therapy, and resting LVEF (adjusted hazard ratio per 10% increase in scar, 1.48 [95% confidence interval: 1.22 to 1.80]; p < 0.001). However, non transmural scar/hibernation or markers of myocardial ischemia on PET including global or peri-infarct ischemia, coronary flow reserve, and resting or hyperemic myocardial blood flows were not associated with MAEs in univariable or multivariable analysis. These findings remained robust in subgroup analyses of patients with ICD (n = 223), with ischemic cardiomyopathy (n = 287), and in patients without revascularization after the PET scan (n = 365). CONCLUSIONS: Myocardial scar but not ischemia was associated with appropriate ICD shocks and sudden cardiac death in patients with LVEF ≤35%. These findings have implications for risk-stratification of patients with left ventricular dysfunction who may benefit from ICD therapy.

Cost Effectiveness of Ventricular Tachycardia Ablation Versus Escalation of Antiarrhythmic Drug Therapy: The VANISH Trial.

OBJECTIVES: This analysis uses the data from the randomized controlled trial to assess the cost effectiveness of catheter ablation (n = 132) versus escalated antiarrhythmic therapy (n = 127). BACKGROUND: For survivors of myocardial infarction with implantable cardioverter-defibrillator shocks despite antiarrhythmic drugs, the VANISH (Ventricular Tachycardia Ablation Versus Escalated Antiarrhythmic Drug Therapy in Ischemic Heart Disease) trial demonstrated improved clinical outcomes with catheter ablation compared with more aggressive antiarrhythmic pharmacotherapy. METHODS: Health care resource use and quality-of-life data were used to determine the cost effectiveness of catheter ablation. Published references were used to estimate costs (in 2015 Canadian dollars). The analysis was over 3 years, with a 5% discount rate. Adjustment was made for censoring and baseline utilities. RESULTS: Ablation resulted in greater quality-adjusted life-years (QALYs) than escalated drug therapy did (1.63 vs. 1.49; difference: 0.14; 95% confidence interval [CI]: -0.20 to 0.46) and higher cost ($65,126 vs. $60,269; difference: $4,857; 95% CI: -$19,757 to $27,106); with an incremental cost per QALY gained for ablation versus escalated drug therapy of $34,057 primarily due to the initial costs of ablation, which were partially offset by the costs of subsequent ablations and adverse outcomes in the escalated drug therapy arm. For patients with amiodarone-refractory ventricular tachycardia, ablation dominated escalated drug therapy, with greater QALYs (1.48 vs. 1.26; difference: 0.22; 95% CI: -0.19 to 0.59) and lower costs ($67,614 vs. $68,383; difference: -$769; 95% CI: -$35,330 to $27,092). For those with sotalol-refractory ventricular tachycardia, ablation resulted in similar QALYs (1.90 vs. 1.90; difference: -0.00; 95% CI: -0.59 to 0.62) and higher costs ($60,455 vs. $45,033; difference: $15,422; 95% CI: -$10,968 to $48,555). CONCLUSIONS: For the total trial population, results are suggestive that ablation is cost effective compared with escalation of drug therapy. This result was only manifest for the subgroup of patients whose qualifying arrhythmia occurred despite amiodarone.

A Comparison of Women and Men Undergoing Catheter Ablation for Sustained Monomorphic Ventricular Tachycardia.

INTRODUCTION: Women are underrepresented in clinical studies on catheter ablation (CA) for ventricular tachycardia (VT). The role of gender as a predictor for VT recurrence after CA is unclear and complication rates have not been compared in a large cohort. METHODS AND RESULTS: We analyzed data of consecutive patients undergoing CA for sustained monomorphic VT at our center between 2005 and 2015. A total of 948 patients underwent 1314 ablation procedures: 114 patients without structural heart disease (SHD) (48% female), 486 with coronary artery disease (CAD) (9% female), 301 with nonischemic cardiomyopathy (NICM) (22% female), and 46 with arrhythmogenic right ventricular cardiomyopathy (ARVC) (17% female). Women with CAD and NICM were younger than men at first ablation (63 years vs. 68 years, P = 0.05; resp. 53 years vs. 59 years, P = 0.026) with no other significant differences in baseline characteristics. Age, LVEF, NYHA-class, and VT-recurrence but not gender were independently associated with increased mortality in CAD and NICM. Mortality rates in patients with no SHD and ARVC are low in men (0%, 2.6%) and women (1.8%, 0%). CONCLUSIONS: Although heart disease tends to present later in women, our data do not suggest that women are referred later than men. Women with CAD or NICM and VT present for ablation at younger age with disease severity comparable to men. VT ablation in women can be accomplished with success- and complication rates comparable to male patients in both those with and without SHD.

Electrophysiologic assessment of conduction abnormalities and atrial arrhythmias associated with amyloid cardiomyopathy.

BACKGROUND: Arrhythmias in cardiac amyloidosis (CA) result in significant comorbidity and mortality but have not been well characterized. OBJECTIVE: The purpose of this study was to define intracardiac conduction, atrial arrhythmia substrate, and ablation outcomes in a group of advanced CA patients referred for electrophysiologic study. METHODS: Electrophysiologic study with or without catheter ablation was performed in 18 CA patients. Findings and catheter ablation outcomes were compared to age- and gender-matched non-CA patients undergoing catheter ablation of persistent atrial fibrillation (AF). RESULTS: Supraventricular tachycardias were seen in all 18 CA patients (1 AV nodal reentrant tachycardia, 17 persistent atrial tachycardia [AT]/AF). The HV interval was prolonged (>55 ms) in all CA patients, including 6 with normal QRS duration (≤100 ms). Thirteen supraventricular tachycardia ablations were performed in 11 patients. Of these, 7 underwent left atrial (LA) mapping and ablation for persistent AT/AF. Compared to non-CA age-matched comparator AF patients, CA patients had more extensive areas of low-voltage areas LA (63% ± 22% vs 34% ± 22%, P = .009) and a greater number of inducible ATs (3.3 ± 1.9 ATs vs 0.2 ± 0.4 ATs, P <.001). The recurrence rate for AT/AF 1 year after ablation was greater in CA patients (83% vs 25%), and the hazard ratio for postablation AT/AF recurrence in CA patients was 5.4 (95% confidence interval 1.9-35.5, P = .007). CONCLUSION: In this group of patients with advanced CA and atrial arrhythmias, there was extensive conduction system disease and LA endocardial voltage abnormality. Catheter ablation persistent AT/AF in advanced CA was associated with a high recurrence rate and appears to have a limited role in control of these arrhythmias.

Better Lesion Creation And Assessment During Catheter Ablation.

Permanent destruction of abnormal cardiac tissue responsible for cardiac arrhythmogenesis whilst avoiding collateral tissue injury forms the cornerstone of catheter ablation therapy. As the acceptance and performance of catheter ablation increases worldwide, limitations in current technology are becoming increasingly apparent in the treatment of complex arrhythmias such as atrial fibrillation. This review will discuss the role of new technologies aimed to improve lesion formation with the ultimate goal of improving arrhythmia-free survival of patients undergoing catheter ablation of atrial arrhythmias.

Conformational properties of interacting neurofilaments: Monte Carlo simulations of cylindrically grafted apposing neurofilament brushes.

Neurofilaments are essential cytoskeletal filaments that impart mechanical stability to axons. They are mostly assembled from three neurofilament proteins that form the core of the filament and its sidearms. Adjacent neurofilaments interact with each other through their apposing sidearms and attain unique conformations depending on the ionic condition, phosphorylation state, and interfilament separations. To understand the conformational properties of apposing sidearms under various conditions and gain insight into interfilament interactions, we performed Monte Carlo simulations of neurofilament pairs. We employed a sequence-based coarse-grained model of apposing NF sidearms that are end-tethered to cylindrical geometries according to the stoichiometry of the three neurofilament subunits. Monte Carlo simulations were conducted under different conditions such as phosphorylation state, ionic condition, and interfilament separations. Under salt-free conditions, apposing sidearms are found to adopt mutually excluding stretched but bent away conformations that are reminiscent of a repulsive type of interaction. Under physiological conditions, apposing sidearms are found to be in a coiled conformation, suggesting a short-range steric repulsive type of interaction. Increased sidearm mutual interpenetration and a simultaneous decrease in the individual brush heights were observed as the interfilament separation was reduced from 60 to 40 nm. The observed conformations suggest entropic interaction as a likely mechanism for sidearm-mediated interfilament interactions under physiological conditions.

Phosphorylation-mediated conformational changes in the mouse neurofilament architecture: insight from a neurofilament brush model.

Neurofilaments (NFs) are important cytoskeletal filaments that consist of long flexible C-terminal tails that are abundant with charges. The tails attain additional negative charges through serine phosphorylation of Lys-Ser-Pro (KSP) repeat motifs that are particularly found in neurofilament heavy (NF-H) and neurofilament medium (NF-M) proteins. These side-arm protrusions mediate the interaction between neighboring filaments and maintain axonal diameter. However, the precise role of NF proteins and their phosphorylation in regulating interfilament distances and axonal diameter still remains unclear. In this regard, a recent gene replacement study revealed that the phosphorylation of mouse NF-M KSP repeats does not affect axonal cytoarchitecture, challenging the conventional viewpoint on the role of NF phosphorylation. To better understand the effect of phosphorylation, particularly NF-M phosphorylation, we applied a computational method to reveal phosphorylation-mediated conformational changes in mouse NF architecture. We employed a three-dimensional sequence-based coarse-grained NF brush model to perform Monte Carlo simulations of mouse NF by using the sequence and stoichiometry of mouse NF proteins. Our result shows that the phosphorylation of mouse NF-M does not change the radial extension of NF-M side arms under a salt-free condition and in ionic solution, highlighting a structural factor that supports the notion that NF-M KSP phosphorylation has no effect on the axonal diameter of mouse. On the other hand, significant phosphorylation-mediated conformational changes were found in NF-H side arms under the salt-free condition, while the changes in ionic solution are not significant. However, NF-H side arms are found at the periphery of mouse NF architecture, implying a role in linking neighboring filaments.