340 research outputs found

    Bilateral branch pulmonary artery valve implantation in repaired tetralogy of fallot

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    BackgroundTranscatheter, bilateral branch pulmonary artery (PA) valve implantation is a novel treatment for patients with severe pulmonary insufficiency and oversized right ventricle (RV) outflow tract. There is scarce data on efficacy and safety of this approach.MethodsThis was a retrospective study of 8 patients with repaired tetralogy of fallot (TOF) who underwent bilateral branch PA valve implantation. Demographics, echocardiography, cardiac catheterization, and axial imaging data were reviewed. Variables were compared by a paired sample t‐test.ResultsAll patients were adult sized (weight 43–99 kg) with oversized RV outflow tract not suitable for conventional transcatheter pulmonary valve implantation. Staged bare metal PA stenting followed by valve implantation (interval 3–5 months) was technically successful in 7 patients with one stent embolization. In another patient, proximal stent migration prevented placement of bilateral pulmonary valve stents. There were a total of 14 valved branch PA stents placed (Melody valve n = 9, Sapien XT n = 2, Sapien 3 n = 3). In the 7 patients undergoing successful branch pulmonary valve placement, at median follow up of 10 months (range 3 months to 6 years), 13 (93%) valves had none/trivial insufficiency on echocardiography. Prevalve and postvalve implantation cardiac magnetic resonance imaging in five patients showed significant reduction of indexed RV end‐diastolic volume (152 ± 27 to 105 ± 15 mL/m2, P < .001).ConclusionsTranscatheter, bilateral branch PA valve implantation was technically feasible with satisfactory efficacy and safety in patients with repaired TOF, severe pulmonary insufficiency, and oversized RV outflow tracts. Elimination of pulmonary insufficiency with this method resulted in reduced RV end‐diastolic volume. This approach can be offered as an alternative to surgery, particularly in patients considered high risk for standard surgical placement and who are not candidates for the newer self‐expanding valve prosthesis for placement in RV outflow tracts larger than 30 mm diameter.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143803/1/ccd27489.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143803/2/ccd27489_am.pd

    Cardiovascular magnetic resonance of pulmonary artery growth and ventricular function after Norwood procedure with Sano modification

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    For hypoplastic left heart syndrome (HLHS), there have been concerns regarding pulmonary artery growth and ventricular dysfunction after first stage surgery consisting of the Norwood procedure modified with a right ventricle-to-pulmonary artery conduit. We report our experience using cardiovascular magnetic resonance (CMR) to determine and follow pulmonary arterial growth and ventricular function in this cohort

    A new methodology to assess the performance and uncertainty of source apportionment models II: The results of two European intercomparison exercises

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    The performance and the uncertainty of receptor models (RMs) were assessed in intercomparison exercises employing real-world and synthetic input datasets. To that end, the results obtained by different practitioners using ten different RMs were compared with a reference. In order to explain the differences in the performances and uncertainties of the different approaches, the apportioned mass, the number of sources, the chemical profiles, the contribution-to-species and the time trends of the sources were all evaluated using the methodology described in Belis et al. (2015). In this study, 87% of the 344 source contribution estimates (SCEs) reported by participants in 47 different source apportionment model results met the 50% standard uncertainty quality objective established for the performance test. In addition, 68% of the SCE uncertainties reported in the results were coherent with the analytical uncertainties in the input data. The most used models, EPA-PMF v.3, PMF2 and EPA-CMB 8.2, presented quite satisfactory performances in the estimation of SCEs while unconstrained models, that do not account for the uncertainty in the input data (e.g. APCS and FA-MLRA), showed below average performance. Sources with well-defined chemical profiles and seasonal time trends, that make appreciable contributions (>10%), were those better quantified by the models while those with contributions to the PM mass close to 1% represented a challenge. The results of the assessment indicate that RMs are capable of estimating the contribution of the major pollution source categories over a given time window with a level of accuracy that is in line with the needs of air quality management

    Results of the first European Source Apportionment intercomparison for Receptor and Chemical Transport Models

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    In this study, the performance of the source apportionment model applications were evaluated by comparing the model results provided by 44 participants adopting a methodology based on performance indicators: z-scores and RMSEu, with pre-established acceptability criteria. Involving models based on completely different and independent input data, such as receptor models (RMs) and chemical transport models (CTMs), provided a unique opportunity to cross-validate them. In addition, comparing the modelled source chemical profiles, with those measured directly at the source contributed to corroborate the chemical profile of the tested model results. The most used RM was EPA- PMF5. RMs showed very good performance for the overall dataset (91% of z-scores accepted) and more difficulties are observed with SCE time series (72% of RMSEu accepted). Industry resulted the most problematic source for RMs due to the high variability among participants. Also the results obtained with CTMs were quite comparable to their ensemble reference using all models for the overall average (>92% of successful z-scores) while the comparability of the time series is more problematic (between 58% and 77% of the candidates’ RMSEu are accepted). In the CTM models a gap was observed between the sum of source contributions and the gravimetric PM10 mass likely due to PM underestimation in the base case. Interestingly, when only the tagged species CTM results were used in the reference, the differences between the two CTM approaches (brute force and tagged species) were evident. In this case the percentage of candidates passing the z-score and RMSEu tests were only 50% and 86%, respectively. CTMs showed good comparability with RMs for the overall dataset (83% of the z-scores accepted), more differences were observed when dealing with the time series of the single source categories. In this case the share of successful RMSEu was in the range 25% - 34%.JRC.C.5-Air and Climat

    Evaluation of receptor and chemical transport models for PM10 source apportionment

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    In this study, the performance of two types of source apportionment models was evaluated by assessing the results provided by 40 different groups in the framework of an intercomparison organised by FAIRMODE WG3 (Forum for air quality modelling in Europe, Working Group 3). The evaluation was based on two performance indicators: z-scores and the root mean square error weighted by the reference uncertainty (RMSEu), with pre-established acceptability criteria. By involving models based on completely different and independent input data, such as receptor models (RMs) and chemical transport models (CTMs), the intercomparison provided a unique opportunity for their cross-validation. In addition, comparing the CTM chemical profiles with those measured directly at the source contributed to corroborate the consistency of the tested model results. The most commonly used RM was the US EPA- PMF version 5. RMs showed very good performance for the overall dataset (91% of z-scores accepted) while more difficulties were observed with the source contribution time series (72% of RMSEu accepted). Industrial activities proved to be the most difficult sources to be quantified by RMs, with high variability in the estimated contributions. In the CTMs, the sum of computed source contributions was lower than the measured gravimetric PM10 mass concentrations. The performance tests pointed out the differences between the two CTM approaches used for source apportionment in this study: brute force (or emission reduction impact) and tagged species methods. The sources meeting the z-score and RMSEu acceptability criteria tests were 50% and 86%, respectively. The CTM source contributions to PM10 were in the majority of cases lower than the RM averages for the corresponding source. The CTMs and RMs source contributions for the overall dataset were more comparable (83% of the z-scores accepted) than their time series (successful RMSEu in the range 25% - 34%). The comparability between CTMs and RMs varied depending on the source: traffic/exhaust and industry were the source categories with the best results in the RMSEu tests while the most critical ones were soil dust and road dust. The differences between RMs and CTMs source reconstructions confirmed the importance of cross validating the results of these two families of models
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