Quantitative aortography for assessment of aortic regurgitation in the era of percutaneous aortic valve replacement.

Paravalvular leak (PVL) is a shortcoming that can erode the clinical benefits of transcatheter valve replacement (TAVR) and therefore a readily applicable method (aortography) to quantitate PVL objectively and accurately in the interventional suite is appealing to all operators. The ratio between the areas of the time-density curves in the aorta and left ventricular outflow tract (LVOT-AR) defines the regurgitation fraction (RF). This technique has been validated in a mock circulation; a single injection in diastole was further tested in porcine and ovine models. In the clinical setting, LVOT-AR was compared with trans-thoracic and trans-oesophageal echocardiography and cardiac magnetic resonance imaging. LVOT-AR > 17% discriminates mild from moderate aortic regurgitation on echocardiography and confers a poor prognosis in multiple registries, and justifies balloon post-dilatation. The LVOT-AR differentiates the individual performances of many old and novel devices and is being used in ongoing randomized trials and registries.

Online Quantitative Aortographic Assessment of Aortic Regurgitation After TAVR: Results of the OVAL Study.

OBJECTIVES: The aim of this study was to investigate the online assessment feasibility of aortography using videodensitometry in the catheterization laboratory during transcatheter aortic valve replacement (TAVR). BACKGROUND: Quantitative assessment of regurgitation after TAVR through aortography using videodensitometry is simple, reproducible, and validated in vitro, in vivo, in clinical trials, and in "real-world" patients. However, thus far the assessment has been done offline. METHODS: This was a single center, prospective, proof-of-principle, feasibility study. One hundred consecutive patients with aortic stenosis and indications to undergo TAVR were enrolled. All final aortograms were analyzed immediately after acquisition in the catheterization laboratory and were also sent to an independent core laboratory for blinded offline assessment. The primary endpoint of the study was the feasibility of the online assessment of regurgitation (percentage of analyzable cases). The secondary endpoint was the reproducibility of results between the online assessment and the offline analysis by the core laboratory. RESULTS: Patients' mean age was 81 ± 7 years, and 56% were men. The implanted valves were either SAPIEN 3 (97%) or SAPIEN 3 Ultra (3%). The primary endpoint of online feasibility of analysis was 92% (95% confidence interval [CI]: 86% to 97%) which was the same feasibility encountered by the core laboratory (92%; 95% CI: 86% to 97%). Reproducibility assessment showed a high correlation between online and core laboratory evaluations (R2 = 0.87, p < 0.001), with an intraclass correlation coefficient of 0.962 (95% CI: 0.942 to 0.975; p < 0.001). CONCLUSIONS: This study showed high feasibility of online quantitative assessment of regurgitation and high agreement between the online examiner and core laboratory. These results may pave the way for the application of videodensitometry in the catheterization laboratory after TAVR. (Online Videodensitometric Assessment of Aortic Regurgitation in the Cath-Lab [OVAL]; NCT04047082).

Hinge point-based annular plane with abnormal aortic cusps in transcatheter aortic valve replacement.

A virtual aortic annular plane that is built using the three hinge points, known as the hinge point-based annular plane (HPAP), is routinely used during transcatheter aortic valve replacement (TAVR). Abnormal aortic cusps (AAC) with unequal length and size influence the relationship of the HPAP to the aortic root axis significantly and pose challenges to valve deployment, leading to paravalvular leak and valve embolisation. Obtaining a centreline-based aortic annular plane in addition may help to understand valve deployment behaviour in AAC better.

"Vascular Outlining": Augmented Imaging for Transfemoral Access-A Preclinical Investigation.

BACKGROUND: Advanced visualization software tools have been used in clinics to improve the safety and accuracy of transcatheter procedure. Imaging techniques have greatly evolved during the era of transcatheter aortic valve implantation (TAVI). In a retrospective analysis, we investigated the feasibility of augmented fluoroscopy for iliofemoral access using a novel "Vascular Outlining" roadmapping technology. METHODS: The Vascular Outlining prototype device (Philips Healthcare) application was used with iliofemoral angiography of 10 patients undergoing transfemoral TAVI. The software processes any conventional angiographic sequences, extracting the static outline of vessels and projecting the two-dimensional vessel margins as a roadmap on live fluoroscopy. Post-processed results were clinically assessed to determine whether the technical performance of the tool is sufficient. RESULTS: Augmented imaging was possible in all investigated angiography sequences. The analysis of software-generated images showed accurate projection of the two-dimensional outline of the iliofemoral vessels as an overlay on the live fluoroscopy image in most cases. Overlay inaccuracy was only observed in cases with low contrast or patient movement. CONCLUSION: In static and contrasted angiography sequences, "Vascular Outlining" showed accurate image overlay. We identified that the quality of the vascular outline is dependent on the opacification of the contrast injection and the stability of the patient on the table. With further development. this application might increase the accuracy of femoral puncture and reduce the incidence of vascular complications. Clinical trials are needed to confirm these hypotheses.

Transcatheter heart valve interventions: where are we? Where are we going?

Transcatheter heart valve interventions have transformed the outcomes of patients with valvular heart disease (VHD) who are unfavourable candidates for surgery. Technological advances have allowed extension of these interventions to younger or lower risk patients and those with other forms of VHD and may in the future permit earlier treatment of VHD in less symptomatic patients or those with moderate disease. The balance of risks and benefits is likely to differ between lower and higher risk patients, and more evidence is needed to evaluate the net benefit of transcatheter technology in these groups. As academic researchers, clinicians, industry, and patient stakeholders collaborate to research these broader indications for transcatheter valve interventions, it is essential to address (i) device durability and deliverability, (ii) specific anatomical needs (e.g. bicuspid aortic valves, aortic regurgitation, mitral and tricuspid valve disease), (iii) operator training, and (iv) the reinforced importance of the multidisciplinary Heart Team.

Feasibility and applicability of static vascular outline roadmapping during transcatheter aortic valve implantation.

BACKGROUND: We investigated the application and feasibility of a novel software tool designed for the visualization of the aortic root during transcatheter aortic valve implantation (TAVI). The final positioning of the device prior deployment remains the most critical phase during TAVI. METHODS: Philips "Vascular Outlining" prototype application was used during balloon expandable Edwards Lifesciences SapienXT valve deployment. It processes any angiographic sequences, extracting the static outline of vessels and projecting the two-dimensional vessel margins as a roadmap on live fluoroscopy. Preoperational planning, sizing and anatomical assessment of access routes were performed using computed tomography scans and the Philips "HeartNavigator" software. RESULTS: Fifteen high-risk aortic stenosis patients (mean age 82.0±6.6 years) underwent TAVI via transfemoral (N.=8), transapical (N.=4), and transaortic (N.=3) access routes. Mean logistic EuroSCOREs and STS-scores were 19.7±4.3% and 7.9±3.1%, respectively, mean aortic gradient was 66.3±18.3 mmHg. All valves were implanted successfully with none or trivial paravalvular regurgitation in 11 patients, mild in 3 patients, and moderate in 1 patient. TAVI was performed in all cases with only one aortic root contrast media injection during valve deployment. No major stroke or cardiovascular death occurred within 30 days. CONCLUSIONS: "Vascular Outlining"-guided implantation of the SapienXT valve is feasible. This new feature might increase the accuracy of valve placement and also may reduce the need for extra contrast media use during valve deployment. However, the lack of real-time motion compensation limits its wide application, as the overlay does not move together with respiratory and cardiac motion.

Substantial radiation reduction in pediatric and adult congenital heart disease interventions with a novel X-ray imaging technology.

BACKGROUND: Pediatric catheterization exposes patients to varying radiation doses. Concerns over the effects of X-ray radiation dose on the patient population have increased in recent years. This study aims at quantifying the patient radiation dose reduction after the introduction of an X-ray imaging technology using advanced real time image noise reduction algorithms and optimized acquisition chain for fluoroscopy and exposure in a pediatric and adult population with congenital heart disease. METHODS: Patient and radiation dose data was retrospectively collected (July 2012-February 2013) for 338 consecutive patients treated with a system using state of the art image processing and reference acquisition chain (referred as "reference system"). The same data was collected (March-October 2013) for 329 consecutive patients treated with the new imaging technology (Philips AlluraClarity, referred as "new system"). Patients were divided into three weight groups: A) below 10 kg, B) 10-40 kg, and C) over 40 kg. Radiation dose was quantified using dose area product (DAP), while procedure complexity using fluoroscopy time, procedure duration and volume of contrast medium. RESULTS: The new system provides significant patient dose reduction compared to the reference system. Median DAP values were reduced in group A) from 140.6 cGy·cm2 to 60.7 cGy·cm2, in group B) from 700.0 cGy·cm2 to 202.2 cGy·cm2 and in group C) from 4490.4 cGy·cm2 to 1979.8 cGy·cm2 with reduction of 57%, 71% and 56% respectively (p < 0.0001 for all groups). CONCLUSIONS: Despite no other changes in procedural approach, the novel X-ray imaging technology provided substantial radiation dose reduction of 56% or higher.

CT angiography-fluoroscopy fusion imaging for percutaneous transapical access.

OBJECTIVES: The aim of this proof-of-principle study is to validate the accuracy of fusion imaging for percutaneous transapical access (TA). BACKGROUND: Structural heart disease interventions, including TA, are commonly obtained under fluoroscopic guidance, which lacks important spatial information. Computed tomographic angiography (CTA)-fluoroscopy fusion imaging can provide the 3-dimensional information necessary for improved accuracy in planning and guidance of these interventions. METHODS: Twenty consecutive patients scheduled for percutaneous left ventricular puncture and device closure using CTA-fluoroscopy fusion guidance were prospectively recruited. The HeartNavigator software (Philips Healthcare, Best, the Netherlands) was used to landmark the left ventricular epicardium for TA (planned puncture site [PPS]). The PPS landmark was compared with the position of the TA closure device on post-procedure CTA (actual puncture site). The distance between the PPS and actual puncture site was calculated from 2 fixed reference points (left main ostium and mitral prosthesis center) in 3 planes (x, y, and z). The distance from the left anterior descending artery at the same z-plane was also assessed. TA-related complications associated with fusion imaging were recorded. RESULTS: The median (interquartile range [IQR]) TA distance difference between the PPS and actual puncture site from the referenced left main ostium and mitral prosthesis center was 5.00 mm (IQR: 1.98 to 12.64 mm) and 3.27 mm (IQR: 1.88 to 11.24 mm) in the x-plane, 4.48 mm (IQR: 1.98 to 13.08 mm) and 4.00 mm (IQR: 1.62 to 11.86 mm) in the y-plane, and 5.57 mm (IQR: 3.89 to 13.62 mm) and 4.96 mm (IQR: 1.92 to 11.76 mm) in the z-plane. The mean TA distance to the left anterior descending artery was 15.5 ± 7.8 mm and 22.7 ± 13.7 mm in the x- and y-planes. No TA-related complications were identified, including evidence of coronary artery laceration. CONCLUSIONS: With the use of CTA-fluoroscopy fusion imaging to guide TA, the actual puncture site can be approximated near the PPS. Moreover, fusion imaging can help maintain an adequate access distance from the left anterior descending artery, thereby, potentially reducing TA-related complications.

Onset timing of cross-sensory activations and multisensory interactions in auditory and visual sensory cortices.

Here we report early cross-sensory activations and audiovisual interactions at the visual and auditory cortices using magnetoencephalography (MEG) to obtain accurate timing information. Data from an identical fMRI experiment were employed to support MEG source localization results. Simple auditory and visual stimuli (300-ms noise bursts and checkerboards) were presented to seven healthy humans. MEG source analysis suggested generators in the auditory and visual sensory cortices for both within-modality and cross-sensory activations. fMRI cross-sensory activations were strong in the visual but almost absent in the auditory cortex; this discrepancy with MEG possibly reflects the influence of acoustical scanner noise in fMRI. In the primary auditory cortices (Heschl's gyrus) the onset of activity to auditory stimuli was observed at 23 ms in both hemispheres, and to visual stimuli at 82 ms in the left and at 75 ms in the right hemisphere. In the primary visual cortex (Calcarine fissure) the activations to visual stimuli started at 43 ms and to auditory stimuli at 53 ms. Cross-sensory activations thus started later than sensory-specific activations, by 55 ms in the auditory cortex and by 10 ms in the visual cortex, suggesting that the origins of the cross-sensory activations may be in the primary sensory cortices of the opposite modality, with conduction delays (from one sensory cortex to another) of 30-35 ms. Audiovisual interactions started at 85 ms in the left auditory, 80 ms in the right auditory and 74 ms in the visual cortex, i.e., 3-21 ms after inputs from the two modalities converged.

White matter integrity and pictorial reasoning in high-functioning children with autism.

The current study investigated the neurobiological role of white matter in visuospatial versus linguistic processing abilities in autism using diffusion tensor imaging. We examined differences in white matter integrity between high-functioning children with autism (HFA) and typically developing controls (CTRL), in relation to the groups' response times (RT) on a pictorial reasoning task under three conditions: visuospatial, V, semantic, S, and V+S, a hybrid condition allowing language use to facilitate visuospatial transformations. Diffusion-weighted images were collected from HFA and CTRL participants, matched on age and IQ, and significance maps were computed for group differences in fractional anisotropy (FA) and in RT-FA association for each condition. Typically developing children showed increased FA within frontal white matter and the superior longitudinal fasciculus (SLF). HFA showed increased FA within peripheral white matter, including the ventral temporal lobe. Additionally, RT-FA relationships in the semantic condition (S) implicated white matter near the STG and in the SLF within the temporal and frontal lobes to a greater extent in CTRL. Performance in visuospatial reasoning (V, V+S), in comparison, was related to peripheral parietal and superior precentral white matter in HFA, but to the SLF, callosal, and frontal white matter in CTRL. Our results appear to support a preferential use of linguistically-mediated pathways in reasoning by typically developing children, whereas autistic cognition may rely more on visuospatial processing networks.

Neuroimaging of the functional and structural networks underlying visuospatial vs. linguistic reasoning in high-functioning autism.

High-functioning individuals with autism have been found to favor visuospatial processing in the face of typically poor language abilities. We aimed to examine the neurobiological basis of this difference using functional magnetic resonance imaging and diffusion tensor imaging. We compared 12 children with high functioning autism (HFA) to 12 age- and IQ-matched typically developing controls (CTRL) on a pictorial reasoning paradigm under three conditions: V, requiring visuospatial processing; S, requiring language (i.e., semantic) processing; and V+S, a hybrid condition in which language use could facilitate visuospatial transformations. Activated areas in the brain were chosen as endpoints for probabilistic diffusion tractography to examine tract integrity (FA) within the structural network underlying the activation patterns. The two groups showed similar networks, with linguistic processing activating inferior frontal, superior and middle temporal, ventral visual, and temporo-parietal areas, whereas visuospatial processing activated occipital and inferior parietal cortices. However, HFA appeared to activate occipito-parietal and ventral temporal areas, whereas CTRL relied more on frontal and temporal language regions. The increased reliance on visuospatial abilities in HFA was supported by intact connections between the inferior parietal and the ventral temporal ROIs. In contrast, the inferior frontal region showed reduced connectivity to ventral temporal and middle temporal areas in this group, reflecting impaired activation of frontal language areas in autism. The HFA group's engagement of posterior brain regions along with its weak connections to frontal language areas suggest support for a reliance on visual mediation in autism, even in tasks of higher cognition.

Enhanced visual processing contributes to matrix reasoning in autism.

Recent behavioral investigations have revealed that autistics perform more proficiently on Raven's Standard Progressive Matrices (RSPM) than would be predicted by their Wechsler intelligence scores. A widely-used test of fluid reasoning and intelligence, the RSPM assays abilities to flexibly infer rules, manage goal hierarchies, and perform high-level abstractions. The neural substrates for these abilities are known to encompass a large frontoparietal network, with different processing models placing variable emphasis on the specific roles of the prefrontal or posterior regions. We used functional magnetic resonance imaging to explore the neural bases of autistics' RSPM problem solving. Fifteen autistic and eighteen non-autistic participants, matched on age, sex, manual preference and Wechsler IQ, completed 60 self-paced randomly-ordered RSPM items along with a visually similar 60-item pattern matching comparison task. Accuracy and response times did not differ between groups in the pattern matching task. In the RSPM task, autistics performed with similar accuracy, but with shorter response times, compared to their non-autistic controls. In both the entire sample and a subsample of participants additionally matched on RSPM performance to control for potential response time confounds, neural activity was similar in both groups for the pattern matching task. However, for the RSPM task, autistics displayed relatively increased task-related activity in extrastriate areas (BA18), and decreased activity in the lateral prefrontal cortex (BA9) and the medial posterior parietal cortex (BA7). Visual processing mechanisms may therefore play a more prominent role in reasoning in autistics.

Cognitive differences in pictorial reasoning between high-functioning autism and Asperger's syndrome.

We investigated linguistic and visuospatial processing during pictorial reasoning in high-functioning autism (HFA), Asperger's syndrome (ASP), and age and IQ-matched typically developing participants (CTRL), using three conditions designed to differentially engage linguistic mediation or visuospatial processing (visuospatial, V; semantic, S; visuospatial + semantic, V + S). The three groups did not differ in accuracy, but showed different response time profiles. ASP and CTRL participants were fastest on V + S, amenable to both linguistic and nonlinguistic mediation, whereas HFA participants were equally fast on V and V + S, where visuospatial strategies were available, and slowest on S. HFA participants appeared to favor visuospatial over linguistic mediation. The results support the use of linguistic versus visuospatial tasks for characterizing subtypes on the autism spectrum.