A non-contrast self-navigated 3-dimensional MR technique for aortic root and vascular access route assessment in the context of transcatheter aortic valve replacement: proof of concept.

OBJECTIVES: Due to the high prevalence of renal failure in transcatheter aortic valve replacement (TAVR) candidates, a non-contrast MR technique is desirable for pre-procedural planning. We sought to evaluate the feasibility of a novel, non-contrast, free-breathing, self-navigated three-dimensional (SN3D) MR sequence for imaging the aorta from its root to the iliofemoral run-off in comparison to non-contrast two-dimensional-balanced steady-state free-precession (2D-bSSFP) imaging. METHODS: SN3D [field of view (FOV), 220-370 mm(3); slice thickness, 1.15 mm; repetition/echo time (TR/TE), 3.1/1.5 ms; and flip angle, 115��] and 2D-bSSFP acquisitions (FOV, 340 mm; slice thickness, 6 mm; TR/TE, 2.3/1.1 ms; flip angle, 77��) were performed in 10 healthy subjects (all male; mean age, 30.3 �� 4.3 yrs) using a 1.5-T MRI system. Aortic root measurements and qualitative image ratings (four-point Likert-scale) were compared. RESULTS: The mean effective aortic annulus diameter was similar for 2D-bSSFP and SN3D (26.7 �� 0.7 vs. 26.1 �� 0.9 mm, p = 0.23). The mean image quality of 2D-bSSFP (4; IQR 3-4) was rated slightly higher (p = 0.03) than SN3D (3; IQR 2-4). The mean total acquisition time for SN3D imaging was 12.8 �� 2.4 min. CONCLUSIONS: Our results suggest that a novel SN3D sequence allows rapid, free-breathing assessment of the aortic root and the aortoiliofemoral system without administration of contrast medium. KEY POINTS: ��� The prevalence of renal failure is high among TAVR candidates. ��� Non-contrast 3D MR angiography allows for TAVR procedure planning. ��� The self-navigated sequence provides a significantly reduced scanning time.

AN INVESTIGATION OF VARIABLE VALVE TIMING EFFECTS ON HCCI ENGINE PERFORMANCE

The Homogeneous Charge Compression Ignition (HCCI) engine is a promising combustion concept for reducing NOx and particulate matter (PM) emissions and providing a high thermal efficiency in internal combustion engines. This concept though has limitations in the areas of combustion control and achieving stable combustion at high loads. For HCCI to be a viable option for on-road vehicles, further understanding of its combustion phenomenon and its control are essential. Thus, this thesis has a focus on both the experimental setup of an HCCI engine at Michigan Technological University (MTU) and also developing a physical numerical simulation model called the Sequential Model for Residual Affected HCCI (SMRH) to investigate performance of HCCI engines. The primary focus is on understanding the effects of intake and exhaust valve timings on HCCI combustion. For the experimental studies, this thesis provided the contributions for development of HCCI setup at MTU. In particular, this thesis made contributions in the areas of measurement of valve profiles, measurement of piston to valve contact clearance for procuring new pistons for further studies of high geometric compression ratio HCCI engines. It also consists of developing and testing a supercharging station and the setup of an electrical air heater to extend the HCCI operating region. The HCCI engine setup is based on a GM 2.0 L LHU Gen 1 engine which is a direct injected engine with variable valve timing (VVT) capabilities. For the simulation studies, a computationally efficient modeling platform has been developed and validated against experimental data from a single cylinder HCCI engine. In-cylinder pressure trace, combustion phasing (CA10, CA50, BD) and performance metrics IMEP, thermal efficiency, and CO emission are found to be in good agreement with experimental data for different operating conditions. Effects of phasing intake and exhaust valves are analyzed using SMRH. In addition, a novel index called Fuel Efficiency and Emissions (FEE) index is defined and is used to determine the optimal valve timings for engine operation through the use of FEE contour maps.

Regulation of bone marrow stem cells through oscillatory shear stresses - A heart valve tissue engineering perspective

Heart valve disease occurs in adults as well as in pediatric population due to age-related changes, rheumatic fever, infection or congenital condition. Current treatment options are limited to mechanical heart valve (MHV) or bio-prosthetic heart valve (BHV) replacements. Lifelong anti-coagulant medication in case of MHV and calcification, durability in case of BHV are major setbacks for both treatments. Lack of somatic growth of these implants require multiple surgical interventions in case of pediatric patients. Advent of stem cell research and regenerative therapy propose an alternative and potential tissue engineered heart valves (TEHV) treatment approach to treat this life threatening condition. TEHV has the potential to promote tissue growth by replacing and regenerating a functional native valve. Hemodynamics play a crucial role in heart valve tissue formation and sustained performance. The focus of this study was to understand the role of physiological shear stress and flexure effects on de novo HV tissue formation as well as resulting gene and protein expression. A bioreactor system was used to generate physiological shear stress and cyclic flexure. Human bone marrow mesenchymal stem cell derived tissue constructs were exposed to native valve-like physiological condition. Responses of these tissue constructs to the valve-relevant stress states along with gene and protein expression were investigated after 22 days of tissue culture. We conclude that the combination of steady flow and cyclic flexure helps support engineered tissue formation by the co-existence of both OSS and appreciable shear stress magnitudes, and potentially augment valvular gene and protein expression when both parameters are in the physiological range. ^

Lethal heparin-induced thrombocytopenia after transfemoral aortic valve implantation

SIN FINANCIACI��N

Comparison of 1-year outcome in patients with severe aorta stenosis treated conservatively or by aortic valve replacement or by percutaneous transcatheter aortic valve implantation (data from a multicenter Spanish registry)

The factors that influence decision making in severe aortic stenosis (AS) are unknown. Our aim was to assess, in patients with severe AS, the determinants of management and prognosis in a multicenter registry that enrolled all consecutive adults with severe AS during a 1-month period. One-year follow-up was obtained in all patients and included vital status and aortic valve intervention (aortic valve replacement [AVR] and transcatheter aortic valve implantation [TAVI]). A total of 726 patients were included, mean age was 77.3 �� 10.6 years, and 377 were women (51.8%). The most common management was conservative therapy in 468 (64.5%) followed by AVR in 199 (27.4%) and TAVI in 59 (8.1%). The strongest association with aortic valve intervention was patient management in a tertiary hospital with cardiac surgery (odds ratio 2.7, 95% confidence interval 1.8 to 4.1, p <0.001). The 2 main reasons to choose conservative management were the absence of significant symptoms (136% to 29.1%) and the presence of co-morbidity (128% to 27.4%). During 1-year follow-up, 132 patients died (18.2%). The main causes of death were heart failure (60% to 45.5%) and noncardiac diseases (46% to 34.9%). One-year survival for patients treated conservatively, with TAVI, and with AVR was 76.3%, 94.9%, and 92.5%, respectively, p <0.001. One-year survival of patients treated conservatively in the absence of significant symptoms was 97.1%. In conclusion, most patients with severe AS are treated conservatively. The outcome in asymptomatic patients managed conservatively was acceptable. Management in tertiary hospitals is associated with valve intervention. One-year survival was similar with both interventional strategies.

Incidence and clinical impact of infective endocarditis after transcatheter aortic valve implantation

The aim of this study is to describe the characteristics of infective endocarditis (IE) after transcatheter aortic valve implantation (TAVI). This study was performed using the GAMES database, a national prospective registry of consecutive patients with IE in 26 Spanish hospitals. Of the 739 cases of IE diagnosed during the study, 1.3% were post-TAVI IE, and these 10 cases, contributed by five centres, represented 1.1% of the 952 TAVIs performed. Mean age was 80 years. All valves were implanted transfemorally. IE appeared a median of 139 days after implantation. The mean age-adjusted Charlson comorbidity index was 5.45. Chronic kidney disease was frequent (five patients), as were atrial fibrillation (five patients), chronic obstructive pulmonary disease (four patients), and ischaemic heart disease (four patients). Six patients presented aortic valve involvement, and four only mitral valve involvement; the latter group had a higher percentage of prosthetic mitral valves (0% vs. 50%). Vegetations were found in seven cases, and four presented embolism. One patient underwent surgery. Five patients died during follow-up: two of these patients died during the admission in which the valve was implanted. Conclusions: IE is a rare but severe complication after TAVI which affects about 1% of patients and entails a relatively high mortality rate. IE occurred during the first year in nine of the 10 patients.

Genomics to elucidate the molecular basis of calcific aortic valve disease

Le r��tr��cissement valvulaire aortique (RVA) est caus�� par une calcification et une fibrose progressive de la valve aortique. Le risque de d��velopper la maladie augmente avec l�����ge. �� cause de l���augmentation de l���esp��rance de vie, le RVA est devenu un probl��me de sant�� publique. Le RVA est fatal en absence de traitement m��dical. Actuellement, la chirurgie est le seul traitement pour le stade s��v��re de la maladie, mais pr��s de 50% des individus avec RVA n���y sont pas ��ligibles, principalement due �� la pr��sence de comorbidit��s. Plusieurs processus biologiques ont ��t�� associ��s �� la maladie, mais les voies mol��culaires sp��cifiques et les g��nes impliqu��s dans le d��veloppement et la progression du RVA ne sont pas connus. Il est donc urgent de d��couvrir les g��nes de susceptibilit�� pour le RVA afin d���identifier les personnes �� risque ainsi que les biomarqueurs et les cibles th��rapeutiques pouvant mener au d��veloppement de m��dicaments pour inverser ou limiter la progression de la maladie. L���objectif de cette th��se de doctorat ��tait d���identifier la base mol��culaire du RVA. Des approches modernes en g��nomique, incluant l�����tude de g��nes candidats et le criblage g��nomique par association (GWAS), ont ��t�� r��alis��es �� l���aide de collections d���ADN provenant d���un grand nombre de patients bien caract��ris��s pour le RVA. Des ��tudes compl��mentaires en transciptomique ont compar�� le profil d���expression global des g��nes entre des valves calcifi��es et non-calcifi��es �� l���aide de biopuces �� ADN et de s��quen��age de l���ARN. Une premi��re ��tude a identifi�� des variations dans le g��ne NOTCH1 et sugg��re pour la premi��re fois la pr��sence d���un polymorphisme commun dans ce g��ne conf��rant une susceptibilit�� au RVA. La deuxi��me ��tude a combin�� par m��ta-analyse deux GWAS de patients provenant de la ville de Qu��bec et Paris (France) aux donn��es transcriptomiques. Cette ��tude de g��nomique int��grative a confirm�� le r��le de RUNX2 dans le RVA et a permis l���identification d���un nouveau g��ne de susceptibilit��, CACNA1C. Les troisi��me et quatri��me ��tudes sur l���expression des g��nes ont permis de mieux comprendre les bases mol��culaires de la calcification des valves aortiques bicuspides et ainsi d���identifier de nouvelles cibles th��rapeutiques pour le RVA. Les donn��es g��n��r��es par ce projet sont la base de futures d��couvertes importantes qui permettront d���am��liorer les options de traitement et la qualit�� de vie des patients atteints du RVA.

Studio sulla sclerocronologia e microstruttura delle valve malformate di Pinna nobilis per dimostrarne la capacit�� rigenerativa

Il presente studio si pone l���obbiettivo di indagare la capacit�� rigenerativa di P. nobilis, poich�� sono stati osservati in natura individui con probabile ricostruzione delle valve a seguito di danneggiamenti, frequenti in questa specie sessile ed infossata solo in parte nel sedimento. La rigenerazione di parte del guscio potrebbe essere resa possibile in questa specie dalla presenza del mantello ���fluido���, non fissato ai lobi della valva e di conseguenza notevolmente retrattile. Sono state analizzate le valve di 19 esemplari che presentavano anomalie strutturali. I campioni provengono da individui morti raccolti durante differenti campagne effettuate in tre aree mediterranee: delta dell���Ebro (Spagna), laguna veneta (Italia) e Port de S��te (Francia). L���analisi dei campioni �� avvenuta attraverso l���osservazione microscopica delle sezioni dell���impronta del muscolo adduttore posteriore. In tre campioni, provenienti da aree diverse, �� stato possibile documentare l���effettiva ricostruzione delle valve, resa evidente dall���intrusione di depositi di calcite all���interno della madreperla, che si inspessiscono gradualmente in direzione posteriore fino alla formazione della nuova conchiglia. Lo spessore sottile del nuovo strato di calcite e l���assenza delle marche annuali, caratteristiche simili della fase giovanile (in cui l���individuo si accresce velocemente), fa supporre che la ricostruzione avvenga molto rapidamente, ci�� sarebbe giustificato dalla necessit�� di riparare velocemente il danno subito. In tre campioni, nonostante l���avvenuta divisione della valva, �� assente il deposito di calcite all���interno della madreperla, probabilmente a causa della ricostruzione avvenuta ad un livello pi�� posteriore. I restanti campioni hanno permesso di osservare la riparazione di piccole porzioni di guscio e dell���apice anteriore e la presenza di depositi di calcite pi�� spessi, probabilmente dovuti al maggior apporto di proteine.

Desenvolvimento e avalia����o de uma servov��lvula de baixo custo para a aplica����o de insumos l��quidos

The present work aimed the development of a low cost servo-valve that answers to an electronic control signal, for variable rates liquid inputs application. A literature research to define which valve type should be used was made. A mechanically activated proportional valve with an electronically controlled servo-engine was designed and evaluated. Since developed the servo-valve, the system was submited to a number of tests .The evaluation of its behavior was obtained in terms of repeatability, hystheresis and linearity. The test was accomplished in a bench, specially developed for this aim. As a result, were obtained three curves of opening percentage as function of flow rate, describing three opening and closing increments in two different work pressures. The servo-valve presented a good repeatability, reasonable hysteresis and a typically quadratic curve. This one maintained the low cost target. These results were very satisfied because the non-linearity and the hysteresis could be easily corrected by software.

Deriva����o ventriculoperitoneal com v��lvula no tratamento da hidrocefalia infantil

From December-1965 to November-1969, 95 hydrocephalic infants have been operated upon using ventriculoperitoneal shunt with valve (88 cases with a Spitz-Holter valve, 6 cases with a Hakim valve and one case with a Pudenz-Heyer valve). Up to the present time (December, 1970) a total of 54 children are alive with a compensated hydrocephalus and 9 patients died, being impossible to follow-up the 32 remaining cases. The use of the ventriculoperitoneal shunt has eliminated all cardiovascular-pulmonary complications and reduced the number for surgical revisions. Besides, infections involving the draining system are less severe and more easily controlled than those occurring in the ventriculoatrial shunts. After analysis of the surgical techniques as well as complications and results the following conclusions are stated: 1) the use of a valve in the ventriculoperitoneal shunt difficults the oclusion of the peritoneal end of the draining system; 2) good results can be expected without reoperations in about 42,35% of hydrocephalus cases treated by ventriculoperitoneal shunt with valve; 3) ventriculoperitoneal shunts with valve showed better results when compared to ventriculoatrial shunts. This statement is made comparing two groups of hydrocephalic infants submitted to surgery at the same Service and in the same conditions, with the same follow-up period; 4) the cases presented permit to state that at present time the ventriculoperitoneal shunt with valve is the most suitable surgical procedure for hydrocephalus.

Recrea����o e lazer como integrantes de curriculos dos cursos de gradua����o em educa����o fisica

Universidade Estadual de Campinas . Faculdade de Educa����o F��sica

Recrea����o e lazer como integrantes dos curriculos dos cursos de gradua����o em educa����o fisica

Universidade Estadual de Campinas. Faculdade de Educa����o F��sica

Doen��a periodontal em portadoras de valvopatia durante a gravidez: estudo cl��nico e microbiol��gico

FUNDAMENTO: A doen��a periodontal representa risco �� gestante portadora de valvopatia reum��tica, seja para contrair endocardite infecciosa, seja por propiciar complica����es obst��tricas. OBJETIVO: Estudar a frequ��ncia da doen��a periodontal em portadoras de valvopatia reum��tica durante a gravidez. M��TODOS: Foram estudadas 140 gestantes, compar��veis quanto a idade e o n��vel socioecon��mico, divididas em: 70 portadoras de doen��a valvar reum��tica e 70 mulheres saud��veis. Todas se submeteram a: 1) avalia����o cl��nica odontol��gica que incluiu a an��lise dos seguintes par��metros: 1.1) profundidade �� sondagem, 1.2) dist��ncia da linha esmalte-cemento �� margem gengival, 1.3) n��vel cl��nico de inser����o, 1.4) ��ndice de sangramento, 1.5) ��ndice de placa bacteriana, e, 1.6) comprometimento de furca; e, 2) exame microbiol��gico nas amostras de saliva e do cone que considerou o controle positivo para as cepas das bact��rias Porphyromonas gingivalis, Tannerella forsithia e Aggregobacter actinomycetemcomitans. RESULTADOS: A les��o valvar mitral foi prevalente (65 casos = 92,8%) dentre as gestantes cardiopatas. A compara����o entre os grupos mostrou n��o haver diferen��as entre idade e a paridade, e embora tenham sido verificadas diferen��as entre as medidas da dist��ncia da linha esmalte-cemento �� margem gengival (p = 0,01) e o ��ndice de placa (p=0,04), a frequ��ncia da doen��a periodontal identificada em 20 (14,3%) gestantes, n��o foi diferente entre os grupos (p = 0,147). O exame microbiol��gico mostrou uma propor����o maior da bact��ria P. gingivalis na saliva de gestantes saud��veis (p = 0,004). CONCLUS��O: O estudo cl��nico e microbiol��gico periodontal durante a gravidez demonstrou igual frequ��ncia da doen��a periodontal em portadoras de valvopatia reum��tica quando comparada ��s mulheres saud��veis.