Artificial enveloping reverberation for binaural auralization using reciprocal maximum-length sequences

Binaural auralization through proper room-acoustic simulation can produce a realistic listening experience as if the listener were sitting in a room with spatial perception, including enveloping reverberance. Based on analysis of experimentally measured binaural room-acoustic data, this paper discusses an approach to creating artificial but natural-sounding reverberation for binaural rendering that can be employed in simulating such an environment in an efficient way. Approaches to adjusting the spaciousness of enveloping reverberance within the context of artificially generated reverberation are investigated via hearing tests. This paper exploits the excellent pseudorandom properties of maximum-length sequences to generate deterministic and controllable decorrelations between binaural channels for artificial reverberation for room-acoustic simulations with high computational efficiency. To achieve natural-sounding enveloping reverberance in an enclosed space, and thereby an immersive environment, the shapes of both the reverberation energy decays and the spatial characteristics are found to be decisive. This paper discusses systematic hearing test results that support the mentioned finding.

Bilateral versus Single Internal-Thoracic-Artery Grafts at 10 Years

BACKGROUND

Multiple arterial grafts may result in longer survival than single arterial grafts after coronary-artery bypass grafting (CABG) surgery. We evaluated the use of bilateral internal-thoracic-artery grafts for CABG.

METHODS

We randomly assigned patients scheduled for CABG to undergo bilateral or single internal-thoracic-artery grafting. Additional arterial or vein grafts were used as indicated. The primary outcome was death from any cause at 10 years. The composite of death from any cause, myocardial infarction, or stroke was a secondary outcome.

RESULTS

A total of 1548 patients were randomly assigned to undergo bilateral internal-thoracic-artery grafting (the bilateral-graft group) and 1554 to undergo single internal-thoracic-artery grafting (the single-graft group). In the bilateral-graft group, 13.9% of the patients received only a single internal-thoracic-artery graft, and in the single-graft group, 21.8% of the patients also received a radial-artery graft. Vital status was not known for 2.3% of the patients at 10 years. In the intention-to-treat analysis at 10 years, there were 315 deaths (20.3% of the patients) in the bilateral-graft group and 329 deaths (21.2%) in the single-graft group (hazard ratio, 0.96; 95% confidence interval [CI], 0.82 to 1.12; P=0.62). Regarding the composite outcome of death, myocardial infarction, or stroke, there were 385 patients (24.9%) with an event in the bilateral-graft group and 425 patients (27.3%) with an event in the single-graft group (hazard ratio, 0.90; 95% CI, 0.79 to 1.03).

CONCLUSIONS

Among patients who were scheduled for CABG and had been randomly assigned to undergo bilateral or single internal-thoracic-artery grafting, there was no significant between-group difference in the rate of death from any cause at 10 years in the intention-to-treat analysis. Further studies are needed to determine whether multiple arterial grafts provide better outcomes than a single internal-thoracic-artery graft. (Funded by the British Heath Foundation and others; Current Controlled Trials number, ISRCTN46552265 .).

Optimised isolation method for RNA extraction suitable for RNA sequencing from feline teeth collected in a clinical setting and at post mortem

Advanced next generation sequencing approaches have started to reveal the cellular and molecular complexity of the microenvironment in many tissues. It is challenging to obtain high quality RNA from mineralised tissues. We developed an optimised method of RNA extraction from feline teeth collected in a clinical setting and at post mortem. Teeth were homogenised in phenol-guanidinium solution at near-freezing temperatures and followed by solid-phase nucleic acid extraction utilising a commercially available kit. This method produced good RNA yields and improved RNA quality based on RNA integrity numbers equivalent (RIN^e) from an average of 3.6 to 5.6. No correlation was found between RNA purity parameters measured by A_260:280 or A_230:260 ratios and degree of RNA degradation. This implies that RNA purity indicators cannot be reliably used as parameters of RNA integrity. Two reference genes (GAPDH, RPS19) showed significant changes in expression levels by qPCR at low and moderate RIN^e values, while RPL17 was stable at all RIN^e values tested. Furthermore, we investigated the effect of quantity and quality of RNA on the quality of the resultant RNA sequencing (RNA-Seq) data. Thirteen RNA-seq data showed similar duplication and mapping rates (94 to 95%) against the feline genome regardless of RIN^e values. However one low yield sample with a high RIN^e value showed a high duplication rate and it was an outlier on the RNA-seq multidimensional scaling plot. We conclude that the overall yield of RNA was more important than quality of RNA for RNA-seq quality control. These results will guide researchers who wish to perform RNA extractions from mineralised tissues, especially if collecting in a clinical setting with the recognised restraints that this imposes.

Inadequacy of existing clinical prediction models for predicting mortality after transcatheter aortic valve implantation

BACKGROUND

The performance of emerging transcatheter aortic valve implantation (TAVI) clinical prediction models (CPMs) in national TAVI cohorts distinct from those where they have been derived is unknown. This study aimed to investigate the performance of the German Aortic Valve, FRANCE-2, OBSERVANT and American College of Cardiology (ACC) TAVI CPMs compared with the performance of historic cardiac CPMs such as the EuroSCORE and STS-PROM, in a large national TAVI registry.

METHODS

The calibration and discrimination of each CPM were analyzed in 6676 patients from the UK TAVI registry, as a whole cohort and across several subgroups. Strata included gender, diabetes status, access route, and valve type. Furthermore, the amount of agreement in risk classification between each of the considered CPMs was analyzed at an individual patient level.

RESULTS

The observed 30-day mortality rate was 5.4%. In the whole cohort, the majority of CPMs over-estimated the risk of 30-day mortality, although the mean ACC score (5.2%) approximately matched the observed mortality rate. The areas under ROC curve were between 0.57 for OBSERVANT and 0.64 for ACC. Risk classification agreement was low across all models, with Fleiss's kappa values between 0.17 and 0.50.

CONCLUSIONS

Although the FRANCE-2 and ACC models outperformed all other CPMs, the performance of current TAVI-CPMs was low when applied to an independent cohort of TAVI patients. Hence, TAVI specific CPMs need to be derived outside populations previously used for model derivation, either by adapting existing CPMs or developing new risk scores in large national registries.

Percutaneous coronary angioplasty versus coronary artery bypass grafting in treatment of unprotected left main stenosis (NOBLE): a prospective, randomised, open-label, non-inferiority trial

BACKGROUND

Coronary artery bypass grafting (CABG) is the standard treatment for revascularisation in patients with left main coronary artery disease, but use of percutaneous coronary intervention (PCI) for this indication is increasing. We aimed to compare PCI and CABG for treatment of left main coronary artery disease.

METHODS

In this prospective, randomised, open-label, non-inferiority trial, patients with left main coronary artery disease were enrolled in 36 centres in northern Europe and randomised 1:1 to treatment with PCI or CABG. Eligible patients had stable angina pectoris, unstable angina pectoris, or non-ST-elevation myocardial infarction. Exclusion criteria were ST-elevation myocardial infarction within 24 h, being considered too high risk for CABG or PCI, or expected survival of less than 1 year. The primary endpoint was major adverse cardiac or cerebrovascular events (MACCE), a composite of all-cause mortality, non-procedural myocardial infarction, any repeat coronary revascularisation, and stroke. Non-inferiority of PCI to CABG required the lower end of the 95% CI not to exceed a hazard ratio (HR) of 1·35 after up to 5 years of follow-up. The intention-to-treat principle was used in the analysis if not specified otherwise. This trial is registered with ClinicalTrials.gov identifier, number NCT01496651.

FINDINGS

Between Dec 9, 2008, and Jan 21, 2015, 1201 patients were randomly assigned, 598 to PCI and 603 to CABG, and 592 in each group entered analysis by intention to treat. Kaplan-Meier 5 year estimates of MACCE were 29% for PCI (121 events) and 19% for CABG (81 events), HR 1·48 (95% CI 1·11-1·96), exceeding the limit for non-inferiority, and CABG was significantly better than PCI (p=0·0066). As-treated estimates were 28% versus 19% (1·55, 1·18-2·04, p=0·0015). Comparing PCI with CABG, 5 year estimates were 12% versus 9% (1·07, 0·67-1·72, p=0·77) for all-cause mortality, 7% versus 2% (2·88, 1·40-5·90, p=0·0040) for non-procedural myocardial infarction, 16% versus 10% (1·50, 1·04-2·17, p=0·032) for any revascularisation, and 5% versus 2% (2·25, 0·93-5·48, p=0·073) for stroke.

INTERPRETATION

The findings of this study suggest that CABG might be better than PCI for treatment of left main stem coronary artery disease.

FUNDING

Biosensors, Aarhus University Hospital, and participating sites.

A comparison between surgical risk scores for predicting outcome in patients undergoing transcatheter aortic valve implantation

BACKGROUND

Surgical risk scoring systems are of modest value in predicting outcome following transcatheter aortic valve implantation (TAVI). There is no consensus as to which scoring system is the most useful. We examined the efficacy of all four currently available global scorings systems (Additive EuroScore [aES], Logistic EuroScore [LES], EuroScore II [ES II], Society of Thoracic Surgeons [STS] Score) in predicting outcome, both in the short (30 day) and longer term, in patients undergoing TAVI.

METHODS

Additive EuroScore (aES), Logistic EuroScore (LES), EuroScore II (ES II), and Society of Thoracic Surgeons (STS) score were assessed in 312 consecutive TAVI patients. Mortality tracking was obtained from the Office of National Statistics as of May 2014.

RESULTS

Mean age was 81.2±7.0 years; 53.2% were male. Mean aES, LES, ESII and STS were 9.7±1.9, 17.4±9.4, 6.1±4.3 and 4.6±2.8, respectively. Thirty-day mortality was 4.8%; long-term mortality (maximum 5.8 years, mean 2.2±1.5 years) was 25.3%. Using both univariate and multivariate modelling all four scoring systems failed to predict outcomes in the short term. In the longer term, univariable analysis demonstrated that higher aES and LES scores were associated with higher mortality (aES P=0.0048, LES P=0.054, respectively). After multivariable analysis, only higher aES remained significant.

CONCLUSIONS

Surgical risk scores are poor at predicting outcomes in patients undergoing TAVI, particularly in the short term.

Comparative survival after transapical, direct aortic, and subclavian transcatheter aortic valve implantation (data from the UK TAVI registry)

Many patients have iliofemoral vessel anatomy unsuitable for conventional transfemoral (TF) transcatheter aortic valve implantation (TAVI). Safe and practical alternatives to the TF approach are, therefore, needed. This study compared outcomes of alternative nonfemoral routes, transapical (TA), direct aortic (DA), and subclavian (SC), with standard femoral access. In this retrospective study, data from 3,962 patients in the UK TAVI registry were analyzed. All patients who received TAVI through a femoral, subclavian, TA, or DA approach were eligible for inclusion. The primary outcome measure was survival up to 2 years. Median Logistic EuroSCORE was similar for SC, DA, and TA but significantly lower in the TF cohort (22.1% vs 20.3% vs 21.2% vs 17.0%, respectively, p <0.0001). Estimated 1-year survival rate was similar for TF (84.6 ± 0.7%) and SC (80.5 ± 3%, p = 0.27) but significantly worse for TA (74.7 ± 1.6%, p <0.001) and DA (75.2 ± 3.3%, p <0.001). A Cox proportional hazard model was used to analyze survival up to 2 years. Survival in the SC group was not significantly different from the TF group (hazard ratio [HR] 1.22, 95% confidence interval [CI] 0.88 to 1.70, p = 0.24). In contrast, survival in the TA (HR 1.74, 95% CI 1.43 to 2.11; p <0.001) and DA (HR 1.55, 95% CI 1.13 to 2.14; p <0.01) cohorts was significantly reduced compared with TF. In conclusion, TA and DA TAVI were associated with similar survival, both significantly worse than with the TF route. In contrast, subclavian access was not significantly different from TF and may represent the safest nonfemoral access route for TAVI.

Poor mobility predicts adverse outcome better than other frailty indices in patients undergoing transcatheter aortic valve implantation

BACKGROUND

Surgical risk scoring systems are poor at predicting outcome in patients undergoing transcatheter aortic valve implantation (TAVI). Frailty indices might more accurately predict outcome.

AIMS

To examine multiple frailty indices as markers of performance to see whether they predict outcomes both in the shorter (30 days) and longer terms (5 years) in patients who have undergone TAVI.

METHODS

Frailty indices (Mobility; Brighton Mobility Index, New York Heart Association (NYHA), Karnofsky Performance Index, Canadian Study Health Association (CSHA) clinical frailty scale, and Katz Index of Dependence) were assessed in 312 consecutive TAVI patients. Mortality tracking was obtained from the Office of National Statistics as of May 2014.

RESULTS

Mean age was 81.2 ± 7.0 years; 53.2% were male. Mean Logistic EuroSCORE and STS were 17.4 ± 9.4 and 4.6 ± 2.8, respectively. Mean peak aortic valve gradient and aortic valve area were 79.1 ± 28.0 mm Hg and 0.72 ± 0.25 cm(2) , respectively. 30-day mortality was 4.8%; long-term mortality (maximum 5.8 years, mean 2.2 ± 1.5 years) was 25.3%. Both univariate and multivariate analyses confirmed poor mobility (defined as severe impairment of mobility secondary to musculoskeletal or neurological dysfunction (Euroscore II risk)), as the best predictor of adverse outcome over both the short-term (OR 4.03, 95% CI (1.36-11.96), P = 0.012 (30 days)) and longer term (OR 2.15, 95% CI (1.33-3.48), P = 0.002, (2.2 ± 1.5 years.)).

CONCLUSION

Poor mobility predicts worse survival among patients undergoing TAVI, both in the shorter and longer terms. Our data suggest that mobility impairment, of either neurological or musculoskeletal etiology, is an appropriate screening measure when considering patients for TAVI.

Transcatheter aortic valve implantation in the United Kingdom: temporal trends, predictors of outcome, and 6-year follow-up: a report from the UK Transcatheter Aortic Valve Implantation (TAVI) Registry, 2007 to 2012

BACKGROUND

We assessed trends in the performance of transcatheter aortic valve implantation in the United Kingdom from the first case in 2007 to the end of 2012. We analyzed changes in case mix, complications, outcomes to 6 years, and predictors of mortality.

METHODS AND RESULTS

Annual cohorts were examined. Mortality outcomes were analyzed in the 92% of patients from England and Wales for whom independent mortality tracking was available. A total of 3980 transcatheter aortic valve implantation procedures were performed. In successive years, there was an increase in frequency of impaired left ventricular function, but there was no change in Logistic EuroSCORE. Overall 30-day mortality was 6.3%; it was highest in the first cohort (2007-2008), after which there were no further significant changes. One-year survival was 81.7%, falling to 37.3% at 6 years. Discharge by day 5 rose from 16.7% in 2007 and 2008 to 28% in 2012. The only multivariate preprocedural predictor of 30-day mortality was Logistic EuroSCORE ≥40. During long-term follow-up, multivariate predictors of mortality were preprocedural atrial fibrillation, chronic obstructive pulmonary disease, creatinine >200 μmol/L, diabetes mellitus, and coronary artery disease. The strongest independent procedural predictor of long-term mortality was periprocedural stroke (hazard ratio=3.00; P<0.0001). Nonfemoral access and postprocedural aortic regurgitation were also significant predictors of adverse outcome.

CONCLUSIONS

We analyzed transcatheter aortic valve implantation in an entire country, with follow-up over 6 years. Although clinical profiles of enrolled patients remained unchanged, longer-term outcomes improved, and patients were discharged earlier. Periprocedural stroke, nonfemoral access, and postprocedural aortic regurgitation are predictors of adverse outcome, along with intrinsic patient risk factors.

Transradial Secondary Arterial Access for Transcatheter Aortic Valve Implantation: Experience and Limitations

OBJECTIVES

The transradial approach limits vascular complications in coronary interventions. The same may be true for transcatheter aortic valve implantation (TAVI). We present our experience using secondary transradial arterial access.

METHODS

Secondary transradial arterial access has been our default strategy for TAVI since 2007. Procedural data is collected prospectively. We assessed procedural success and complications.

RESULTS

Data from 282 patients aged 81±5.2 yrs was examined. Secondary arterial access was transradial (74%), femoral (24%) and none (2%). Secondary femoral access was reserved for failed radial access (3%), anatomical anomalies (4%), operator preference (7%), trial requirements (6%) or proctor preference (4%). The principal pathology was aortic stenosis (90.8%), aortic regurgitation (6.7%) or a combination (2.5%). CoreValve (91.4%), Edwards (7%) or Lotus valves (1.7%) were delivered via transfemoral (88.6%), direct aortic (5.3%), subclavian (3.9%) or transapical approaches (1.8%). Significant vascular complications occurred in 25 cases (9.4%), including surgical repair of a failed percutaneous closure device (n=16), ilio-femoral dissection (n=3), iliac perforations (n=3), plaque disruption (n=1) and false aneurysm (n=2), one of which was from the secondary femoral access site. There was no local vascular complication from the secondary radial site.

CONCLUSIONS

The transradial secondary access route for TAVI is safe and effective. The transradial route may limit vascular access complications from secondary transfemoral access.

Do outcomes from transcatheter aortic valve implantation vary according to access route and valve type? The UK TAVI Registry

OBJECTIVES

To determine whether outcomes from transcatheter aortic valve implantation (TAVI) vary according to access route and valve type in a real-world population.

BACKGROUND

Registry and uncontrolled trial data have found that patients undergoing nonfemoral TAVI have higher early and late mortality. It is not clear whether worse outcomes relate directly to access route. There have been no direct comparisons of outcomes according to valve type.

METHODS

Data were collected prospectively on 1,620 patients undergoing TAVI in the UK and compared in 4 groups: SAPIEN transfemoral (TF); SAPIEN transapical (TA); CoreValve TF, CoreValve subclavian. Univariable and multivariable regression analysis was performed to identify independent predictors of mortality.

RESULTS

Mortality in patients undergoing SAPIEN TAVI via a TA approach was higher than with TF at 30 days (11.2% vs. 4.4%, P < 0.01), 1 year (28.7% vs. 18.1%, P = 0.01), and 2 years (56.0% vs. 43.5%, P = 0.01). Logistic EuroSCORE was higher in TA patients (22.5 ± 12.9% vs. 17.7 ± 11.1%, P < 0.0001). After multivariable analysis TA access was associated with increased mortality at 30 days (OR 2.56, 95% CI 1.46-4.48, P < 0.01) and 2 years (OR 1.75, 1.08-2.74, P = 0.02). There was no significant difference in mortality at any time-point between patients treated with SAPIEN (n = 812) and CoreValve (n = 808) prostheses. CoreValve-treated patients had a higher rate of permanent pacemaker implantation (23.1% vs. 7.2%, P < 0.0001), and grade ≥2 aortic regurgitation on postprocedure echocardiography (13.0% vs. 7.3%, P < 0.01).

CONCLUSIONS

Patients undergoing TA TAVI experienced increased early and late mortality compared to a TF approach. Survival was not influenced by valve type.