Impacto clínico-funcional del traslado directo desde domicilio a un centro con servicio de hemodinamia en el infarto agudo de miocardio con elevación de ST / Clinical-functional impact of direct transfer from home to a center with hemodynamic service in acute myocardial infarction with ST elevation

Antecedentes: la demora en la reperfusión del infarto agudo de miocardio con elevación del ST (IAMCST) es un determinante mayor de su evolución clínica y funcional. Objetivo: analizar el impacto del traslado directo desde domicilio a un centro con hemodinamia sobre los tiempos de reperfusión y la evolución clínico-ecocardiográfica del IAMCST. Material y método: se diseñó un estudio prospectivo, observacional, que incluyó los pacientes con IAMCST recibidos en el servicio de hemodinamia del Instituto de Cardiología Intervencionista de Casa de Galicia (INCI) para angioplastia transluminal coronaria (ATC) primaria del 1º de febrero de 2016 al 30 de setiembre de 2016. Los pacientes se clasificaron en dos grupos: 1) traslado directo desde domicilio a servicio de hemodinamia y 2) traslado desde otro centro asistencial. Se evaluaron los tiempos dolor-primer contacto médico (PCM) y PCM-balón. Se comparó la evolución clínica, la fracción de eyección del ventrículo izquierdo (FEVI) y el score de contractilidad sectorial del VI a corto plazo (a las 48 horas tras el ingreso y al mes) entre ambos grupos. Resultados: se incluyeron 124 pacientes, 38 mujeres (31%), edad media 63,2±13,5 años. El tiempo PCM-balón representó el 54,7% del tiempo isquémico. Provenían de domicilio 51 pacientes (41%). El tiempo de reperfusión en el grupo 1 fue 284±241 min vs 498±309 min en el grupo 2 (p<0,001), mientras que el tiempo PCM-balón del grupo 1 fue 111±76,3 min vs 263±175,1 min del grupo 2, (p<0,001). No existieron diferencias significativas entre los grupos 1 y 2 en referencia a la FEVI medida al ingreso (49,5±9,33% vs 46,5±9,78%) y al mes (53,0±-8,5) vs (50,2±10,5). El score de contractilidad inicial fue menor en el grupo 1 (1,37±0,39) que en el grupo 2 (1,46±0,31) (p=0,029), mientras que no mostró diferencias significativas en el control al mes (1,23±0,26) vs 1,34±0,32. La mortalidad total fue de 12 pacientes (9,7%) y antes de las 48 horas, 8 pacientes (6,5%). La tasa de eventos cardíacos adversos mayores (ECAM: reinfarto, revascularización urgente, muerte y accidente cerebrovascular [ACV]) no difirió entre ambos grupos. Los pacientes que sufrieron ECAM presentaron mayor score de contractilidad inicial y menor FEVI inicial y al mes. Conclusión: la estrategia de traslado directo desde domicilio a un centro de hemodinamia se asocia con un menor tiempo isquémico total a expensas de un menor tiempo PCM-balón, menor tiempo PCM-puerta y con un mejor score de contractilidad segmentaria inicial.

Background: delayed reperfusion of acute myocardial infarction with ST elevation (STEMI) is a major determinant of its clinical and functional course. Objective: to analyze the impact of the direct transfer from home to a center with hemodynamic service on the reperfusion times and in the clinical and echocardiographic evolution of the STEMI. Method: a prospective, observational study was designed that included patients with STEMI received at the INCI hemodynamic service for primary coronary transluminal angioplasty (TCA) from 1st.February 2016 to 30th September 2016. Patients were classified in two groups: 1) direct transfer from home to hemodynamic service and 2) transfer from another care center. Pain-first medical contact (FMC) and FMC-device times were evaluated. The short-term clinical evolution, the left ventricular ejection fraction (LVEF) and left ventricular sector contractility score (at 48 hours post admission and at one month) were compared between both groups. Results: we included 124 patients, 38 (31%) women, mean age 63.2±13.5 years. FMC-device time accounted for 54.7% of ischemic time. 51 patients (41%) were direct transfer from domicile. The reperfusion time in group 1 was 284 ± 241 min vs. 498 ± 309 min in group 2 (p <0.001), while the FMC-device time of group 1 was 111 ± 76.3 min vs 263 ± 175.1 min of group 2, (p <0.001). There were no significant differences between groups 1 and 2 in relation to LVEF measured at admission (49.5 ± 9.33% vs. 46.5 ± 9.78%) and at one month (53.0 ± -8.5) vs. (50.2 ± 10.5). The initial contractility score was lower in group 1 (1.37 ± 0.39) than in group 2 (1.46 ± 0.31) (p = 0.029), whereas it did not show significant differences in control and at one month (1.23 ± 0.26). 1.34 ± 0.32. The total mortality was 12 patients (9.7%) and 8 patients (6.5%) before 48 hours. The rate of major adverse cardiac events (MACE) did not differ between the two groups. Conclusion: the strategy of direct transfer from home to a hemodynamic center is associated with a shorter total ischemic time at the expense of a shorter FMC-device time and a shorter FMC-door time and with a better segmental contractility score.

52. Predictores de mortalidad en pacientes mayores de 80 años revascularizados con ATC

Antecedentes: la población está sufriendo un importante envejecimiento en nuestro país y la angioplastia coronaria se ha constituido en el método de revascularización más frecuentemente utilizado en pacientes añosos. Objetivo: determinar predictores de mortalidad en pacientes mayores de 80 años revascularizados con ATC. Material y método: se realizó un estudio retrospectivo, descriptivo. Se seleccionaron aquellos pacientes de 80 o más años de edad en los que se realizó ATC de al menos una arteria en el período 2010-2016. Se valoraron características de la población considerando factores de riesgo coronario y forma de presentación clínica. Se evaluó la mortalidad y sus predictores. La supervivencia se calculó mediante curvas de Kaplan Meier y se compararon los grupos mediante test de log Rank. Los predictores se calcularon con pruebas de asociación mediante test exacto de Fisher. Resultados: se incluyeron 449 pacientes de los cuales 225 eran mujeres (50,11%) con una edad media de 83,71 (± 2,98) años. Se presentaron como SCACEST 177/449 (39,42%), SCASEST 215/449 (47,88%), sin SCA 145/449 (32%), ATC de rescate 5/449 (1,1%). La mortalidad hospitalaria fue de 22/449 (4,9%) y a 30 días 43/449 (9,58%). La mortalidad hospitalaria en los pacientes con SCACEST fue de 18/177 (10,17%) significativamente mayor que en los SCASEST 2/122, (1,6%, p=0,0037) y que en pacientes sin SCA 2/145 (1,4%, p=0,0025). Al mes la mortalidad también fue mayor en los SCACEST 30/177 (16,95%) que en los SCASEST 6/122(4,9% p=0,0031), y que en los sin SCA 7/145(4,8% p=0,0013). La diabetes resultó ser un predictor independiente de mortalidad hospitalaria: 9,57% en los diabéticos y 3,29% en los no diabéticos (p= 0,011) (IC 95%). A 30 días fueron predictores de mortalidad la ausencia de ATC previa con una mortalidad de 11,40% en los que no tenían ATC y 3,06% de los que sí tenían (p=0,011) y la ATC de TCI con una mortalidad de 23,08% versus 4,36% (p=0,02). Conclusiones: los predictores independientes de mortalidad hospitalaria fueron la diabetes y el SCACEST y los predictores de mortalidad a 30 días fueron la presentación con SCACEST, la ATC de TCI y la ausencia de ATC previa.

49. IAM complicado con disección intramiocárdica del septum

Historia clínica: mujer 78 años. Neoplasma de riñón. Monorrena quirúrgica. Dolor interescapular subintrante de 8 horas de evolución que cede espontáneamente; 72 horas después reconsulta por dolor de similares características acompañado de disnea. Lúcida. PA 90/60 mmHg. Ritmo regular 90 cpm. Sin soplos. Polipnea. Saturación 94%. Ventilan ambos campos pleuropulmonares, estertores crepitantes en tercio inferior. Pruebas complementarias: ECG: infarto anterolateral evolucionado. Troponinas positivas. Resto analítica normal. ETT: trastorno sectorial extenso septal, anterior y apical con disección del septum del VI formando espacio en espesor de septum medio y apical. FEVI 40%. CACG a 72 h del ingreso: ADA ocluida en tercio medio se opacifica por circulación colateral homo y heterocoronaria. Evolución clínica: ingresa a CTI. Se dicute con equipo multidisciplinario y se decide tratamiento conservador. Primeros 7 días requerimiento intravenoso de dobutamina y noradrenalina. Diminución progresiva de los mismos. ETT control: Trastornos sectoriales de cara anterior con aneurisma del VI. FEVI 20%. Luego estable, sin apoyo de drogas. Diuresis conservada con estímulo diurético. Alta viva a los 20 días. Diagnóstico: IAM anterolateral evolucionado. Disección del septum interventricular. Discusión: la rotura parcial de la pared miocárdica en forma de disección intramiocárdica es una complicación infrecuente subaguda del IAM. El ecocardiograma es la piedra angular en el diagnóstico. El mecanismo fisiopatológico se debe a pérdida de fuerzas de tensión y movimiento discinético del miocardio infartado con aumento de la presión intraventricular. Alteraciones de las paredes de vasos pequeños y hemorragia secundaria forman un contenido hemático que conduce a la disección. Hay reportes a nivel de pared libre del VI o VD y septum. El hematoma intramiocárdico puede expandirse a la cavidad adyacente, retraerse espontáneamente o formar trombos. El tratamiento puede ser quirúrgico o conservador no habiendo consenso ante la reducida experiencia. No hay diferencia en la tasa de mortalidad en el seguimiento de algunas series a excepción del grupo de pared libre del VD, que la cirugía mejoró la supervivencia. En nuestra paciente se optó por un tratamiento conservador, se le otorgó el alta a los 20 días del ingreso, falleciendo semanas después.

Initial experience of two national centers in transcatheter aortic prosthesis implantation.

BACKGROUND: Transcatheter aortic valve implantation is an effective alternative to surgical treatment of severe aortic stenosis in patients who are inoperable or at high surgical risk. OBJECTIVES: To report the immediate and follow-up clinical and echocardiographic results of the initial experience of transcatheter aortic valve implantation. METHODS: From 2009 June to 2013 February, 112 patients underwent transcatheter aortic valve implantation. RESULTS: Mean age was 82.5 ± 6.5 years, and the logistic EuroSCORE was 23.6 ± 13.5. Procedural success was 84%. After the intervention, a reduction in the mean systolic gradient was observed (pre: 54.7 ± 15.3 vs. post: 11.7 ± 4.0 mmHg; p < 0.01). Cerebrovascular accidents occurred in 3.6%, vascular complications in 19% and permanent pacemaker was required by 13% of the patients. Thirty-day mortality and at follow-up of 16 ± 11 months was 14% and 8.9% respectively. The presence of chronic obstructive pulmonary disease was the only predictor of mortality at 30 days and at follow-up. During follow up, aortic valve area and mean systolic gradient did not change significantly. CONCLUSIONS: Transcatheter aortic valve implantation is an effective and safe procedure for the treatment of aortic stenosis in high-surgical risk or inoperable patients. The presence of chronic obstructive pulmonary disease was the only independent predictor of mortality identified both in the first month post-intervention and at follow-up.

Experiência Inicial de Dois Centros Nacionais no Implante de Prótese Aórtica Transcateter / Initial Experience of Two National Centers in Transcatheter Aortic Prosthesis Implantation

Fundamento: O implante de prótese aórtica transcateter é uma alternativa efetiva para o tratamento cirúrgico para a correção de estenose aórtica grave em pacientes inoperáveis ou de alto risco cirúrgico. Objetivos: Apresentar os resultados clínicos e ecocardiográficos imediatos e no médio prazo da experiência inicial do implante de prótese aórtica transcateter. Métodos: Entre junho de 2009 e fevereiro de 2013, 112 pacientes foram submetidos a implante de prótese aórtica transcateter. Resultados: A idade média foi 82,5 ± 6,5 anos e o Euro SCORE logístico foi 23,6 ± 13,5. O sucesso do procedimento foi de 84%. Após o implante, houve queda do gradiente sistólico médio (pré = 54,7 ± 15,3 mmHg vs. pós = 11,7 ± 4,0 mmHg; p < 0,01). Acidente vascular cerebral ocorreu em 3,6% dos pacientes, complicações vasculares em 19%, e foi necessário o implante de marca-passo definitivo em 13% dos pacientes nos primeiros 30 dias pós-implante. A mortalidade aos 30 dias e no seguimento médio de 16 ± 11 meses foi, respectivamente, de 14 e de 8,9%. A presença de doença pulmonar obstrutiva crônica foi o único preditor de mortalidade em 30 dias e no seguimento. A área valvar aórtica e o gradiente sistólico médio não apresentaram variações significativas durante o seguimento. Conclusões: O implante de prótese aórtica transcateter é um procedimento eficaz e seguro para o tratamento da estenose aórtica em pacientes de alto risco cirúrgico ou inoperáveis. A presença de doença pulmonar obstrutiva crônica foi o único preditor independente de mortalidade identificado, tanto no primeiro mês pós-intervenção quanto no seguimento mais tardio. .

Background: Transcatheter aortic valve implantation is an effective alternative to surgical treatment of severe aortic stenosis in patients who are inoperable or at high surgical risk. Objectives: To report the immediate and follow-up clinical and echocardiographic results of the initial experience of transcatheter aortic valve implantation. Methods: From 2009 June to 2013 February, 112 patients underwent transcatheter aortic valve implantation. Results: Mean age was 82.5 ± 6.5 years, and the logistic EuroSCORE was 23.6 ± 13.5. Procedural success was 84%. After the intervention, a reduction in the mean systolic gradient was observed (pre: 54.7 ± 15.3 vs. post: 11.7 ± 4.0 mmHg; p < 0.01). Cerebrovascular accidents occurred in 3.6%, vascular complications in 19% and permanent pacemaker was required by 13% of the patients. Thirty-day mortality and at follow-up of 16 ± 11 months was 14% and 8.9% respectively. The presence of chronic obstructive pulmonary disease was the only predictor of mortality at 30 days and at follow-up. During follow up, aortic valve area and mean systolic gradient did not change significantly. Conclusions: Transcatheter aortic valve implantation is an effective and safe procedure for the treatment of aortic stenosis in high-surgical risk or inoperable patients. The presence of chronic obstructive pulmonary disease was the only independent predictor of mortality identified both in the first month post-intervention and at follow-up. .

Análise da incidência e preditores clínicos e ecocardiográficos do refluxo paraprotético aórtico após o implante de prótese aórtica transcateter / Analysis of the incidence and clinical and echocardiographic predictors of paravalvular aortic regurgitation after transcatheter aortic valve implantation

INTRODUÇÃO: A incidência de refluxo paraprotético (RPP) parece maior entre os pacientes submetidos a implante de prótese aórtica transcateter e sua potencial associação com aumento da mortalidade tardia tem suscitado preocupação na comunidade científica. Nosso objetivo foi avaliar a incidência e o impacto clínico e estabelecer preditores do RPP em nossa casuística. MÉTODOS: Entre julho de 2009 e fevereiro de 2013, 112 pacientes foram submetidos a implante de prótese aórtica transcateter. O grau do RPP pós-procedimento foi avaliado segundo os critérios do VARC 2. Dividiu-se a população em grupo RPP ausente/RPP discreto e grupo RPP moderado/RPP grave. RESULTADOS: A média da idade foi de 82,5 ± 3,9 anos, 58,9% eram do sexo feminino e o EuroSCORE logístico foi de 23,6 ± 13,4. Houve queda do gradiente sistólico médio (54,7 ± 15,3 mmHg vs. 11,7 ± 4 mmHg; P < 0,01) e ganho da área valvar aórtica (0,66 ± 0,15 cm² vs. 1,8 ± 0,3 cm²; P < 0,01). Ao final do procedimento, 46,4% não apresentaram RPP, e RRP discreto ou moderado foi observado em 42% e 11,6% dos pacientes. Nenhum paciente apresentou RPP grave. A análise multivariada identificou sexo masculino [odds ratio (OR) 5,85, intervalo de confiança (IC] 1,29-26,7; P = 0,022), valvoplastia aórtica percutânea prévia (OR 18,44, IC 2,30-147,85; P = 0,006), fração de ejeção < 35% (OR 4,160, IC 1,014-17,064; P = 0,048) e presença de hipertensão pulmonar grave (OR 7,649, IC 1,86-31,51; P = 0,005) como preditores independentes de RPP moderado/grave. CONCLUSÕES: A incidência de RPP moderado/grave foi baixa e comparável à de outras casuísticas. Sexo masculino, antecedente de valvoplastia aórtica percutânea prévia, presença de hipertensão pulmonar grave e disfunção ventricular esquerda grave foram preditores independentes dessa complicação.

BACKGROUND: The incidence of paravalvular aortic regurgitation (PAR) seems higher among patients submitted to transcatheter aortic valve implantation and its potential association with an increased late mortality has raised concerns in the scientific community. Our objective was to evaluate the incidence and clinical impact of PAR and establish PAR predictors in our patient population. METHODS: Between July/2009 and February/2013, 112 patients were submitted to transcatheter aortic valve implantation. The degree of PAR after the procedure was assessed according to the VARC 2 criteria. The population was divided into no/mild PAR group and moderate/severe PAR group. RESULTS: Mean age was 82.5 ± 3.9 years, 58.9% were female and the logistic EuroSCORE was 23.6 ± 13.4. There was a decrease in the mean systolic gradient (54.7 ± 15.3 mmHg vs 11.7 ± 4 mmHg; P < 0.01) and a gain in the aortic valve area (0.66 ± 0.15 cm² vs 1.8 ± 0.3 cm²; P < 0.01). At the end of the procedure 46.4% did not have PAR, and mild or moderate PAR was observed in 42% and 11.6% of the patients. No patient presented severe PAR. Multivariate analysis identified male gender [odds ratio (OR) 5.85, confidence interval (CI] 1.29-26.7; P = 0.022), previous percutaneous aortic val­vuloplasty (OR 18.44, CI 2.30-147.85; P = 0.006), ejection fraction < 35% (OR 4.160, CI 1.014-17.064; P = 0.048) and the presence of severe pulmonary hypertension (OR 7.649, CI 1.86-31.51; P = 0.005) as independent predictors of moderate/severe PAR. CONCLUSIONS: The incidence of moderate/severe PAR was low and comparable to other studies. Male gender, history of prior percutaneous aortic valvuloplasty, presence of severe pulmonary hypertension and severe left ventricular dysfunction were independent predictors of this complication.

Evolução muito tardia da valvotomia percutânea por balão na estenose mitral grave / Very late follow-up of percutaneous balloon mitral valvotomy in severe mitral stenosis

INTRODUÇÃO: A valvotomia mitral percutânea por balão é um procedimento seguro e eficaz em pacientes com estenose mitral grave sintomática selecionados, com resultados imediatos e a longo prazo semelhantes aos da intervenção cirúrgica. Este estudo tem o objetivo de descrever os resultados muito tardios das primeiras valvotomias mitrais percutâneas por balão realizadas em nossa instituição e identificar os fatores preditores de reestenose. MÉTODOS: No período de 1987 a 1991, 200 pacientes consecutivos foram submetidos a valvotomia mitral percutânea por balão. Avaliações clínica e ecocardiográfica foram realizadas antes do procedimento, 48 horas após e, então, anualmente. RESULTADOS: A média de idade foi de 32 ± 12 anos, 86,5% eram do sexo feminino e 80,5% encontravam-se em classe funcional III ou IV da New York Heart Association. A média do escore de Wilkins foi de 7,6 ± 1,2 e o sucesso do procedimento ocorreu em 87,5% (175/200) dos pacientes. Durante o seguimento, foram acompanhados 129 pacientes (74%) por 140 ± 79 meses. Reestenose após o primeiro procedimento ocorreu em 46,5% (60/129) dos pacientes, sendo realizada uma segunda valvotomia mitral percutânea por balão em 25 pacientes, uma terceira em 4 pacientes, e uma quarta em 1 paciente. Em cinco anos, a probabilidade livre de reestenose foi de 85%, em 10 anos foi de 60% e em 20 anos, de 36%. O diâmetro do átrio esquerdo (P = 0,034) e o gradiente transvalvar mitral tanto pré (P = 0,013) como pós-procedimento (P = 0,038) foram preditores de reestenose. CONCLUSÕES: Em seguimento clínico muito tardio, a valvotomia mitral percutânea por balão mostrou que os resultados são duradouros em mais de um terço dos pacientes e que a repetição do procedimento pode ser realizada com segurança em pacientes selecionados. A identificação dos preditores de reestenose é útil para guiar a seleção de casos para o procedimento.

BACKGROUND: Percutaneous balloon mitral valvotomy is safe and effective in patients with severe symptomatic mitral stenosis with immediate and long-term results comparable to those of surgical intervention. This study was aimed at reporting the very late follow-up results of the first percutaneous balloon mitral valvotomies performed at our institution and at identifying predictive factors of restenosis. METHODS: From 1987 to 1991, 200 consecutive patients were submitted to percutaneous balloon mitral valvotomy. Clinical and echocardiographic evaluations were performed prior to the procedure, 48 hours after the procedure and annually thereafter. RESULTS: Mean age was 32 ± 12 years; 86.5% were female and 80.5% were in New York Heart Association functional class III or IV. Mean Wilkins score was 7.6 ± 1.2 and procedure success was observed in 87.5% (175/200) of the patients. During follow-up, 129 patients (74%) were followed up for 140 ± 79 months. Restenosis was observed after the first procedure in 46.5% (60/129) patients and a second percutaneous balloon mitral valvotomy was performed in 25 patients, a third one in 4 patients and a fourth one in 1 patient. The probability of being restenosis-free was 85% at 5 years, 60% at 10 years and 36% at 20 years. Left atrial diameter (P = 0.034), and preoperative (P = 0.013) and postoperative (P = 0.038) transvalvar gradient were predictors of restenosis. CONCLUSIONS: In a very late clinical follow-up, percutaneous balloon mitral valvotomy provided long-lasting results in over one-third of the patients and showed that repeated procedures may be performed safely in selected patients. The identification of restenosis predictors is useful for patient selection.

Biomechanics of the ergometric stress tests: regional and local effects on elastic, transitional and muscular human arteries.

UNLABELLED: Ergometric exercise stress tests (EST) give important information about the cardiovascular (CV) response to increased demands. The expected EST-related changes in variables like blood pressure and heart rate are known, but those in the arterial biomechanics are controversial and incompletely characterized. AIMS: a) to characterize the regional and local arterial biomechanical behavior in response to EST, and its temporal profile in the post-EST recovery phase and (b) to compare different arteries biomechanical response to EST. METHODS: In 16 non-trained healthy young subjects the carotid-femoral pulse wave velocity and the carotid, femoral and brachial arterial distensibility were non-invasively evaluated before (Rest) and after EST. Post exercise recordings were obtained 0-1, 4-5, and 9-10 minutes after exercise. RESULTS: The EST resulted in an early increase in the arterial stiffness, evidenced by regional and local parameters. There were quali-quantitative differences among the arterial local stiffness response to EST, when analyzing conjunctly the different postEST recovery stages. The biomechanical changes could not be explained only by blood pressure variations.

Reactive hyperemia-related changes in carotid-radial pulse wave velocity as a potential tool to characterize the endothelial dynamics.

UNLABELLED: Current methods used to evaluate the endothelial function have limitations. The analysis of the pulse wave velocity (PWV) response to transient ischaemia could be an alternative to evaluate the endothelial dynamics. AIMS: To analyze (a) the carotid-radial PWV temporal profile during flow mediated dilatation test, and (b) the PWV changes considering its main vascular geometrical (diameter) and intrinsic (elastic modulus) determinants. METHODS: Sixteen healthy young adults were included. The carotid-radial PWV (strain gauge mechano-transducers), wall thickness and brachial diameter (B-Mode ultrasound) were measured before (basal state), during a forearm cuff inflation (5 minutes) and after its deflation (10 minutes). The PWV, brachial diameter and elastic modulus changes and temporal profile were analyzed (basal state, 15, 30, 45, and 60 seconds after cuff deflation). RESULTS: Transient ischaemia was associated with arterial stiffness changes, evidenced by carotid-radial PWV variations. The PWV and diastolic diameter changes, and temporal profiles differed. The arterial stiffness changes could not be explained only by geometrical (diameter) changes. CONCLUSION: The carotid-radial PWV analysis, evaluated using robust and simple available techniques, could be used in the clinical practice to study the vascular response to transient ischaemia and the endothelial function.

Preservation of muscular and elastic artery distensibility after an intercontinental cryoconserved exchange: theoretical advances in arterial homograft generation and utilization.

While the situation of tissue donation and transplantation differs between Latin American and European countries, a common problem is tissue deficiency. Hence, at present, there is a pressing need to generate alternatives so as to increase the possibilities of obtaining the requested materials. Consequently, it would be of significant interest to establish an intercontinental network for tissue exchange, to improve international cooperation, and to help patients that need tissue transplantation, and to evaluate the feasibility of using an intercontinental network for the exchange of cryopreserved arteries (cryografts), preserving the arterial distensibility and ensuring a reduced native artery-cryograft biomechanical mismatch. Distensibility was studied in ovine arteries divided into three groups: intact (in vivo tests, conscious animals), fresh control (in vitro tests immediately after the artery excision, Uruguay), and cryografts (in vitro tests of cryopreserved-transported-defrosted arteries, Spain). Histological studies were performed so as to analyze changes in the endothelial layer and elastic components. The comparison between fresh control and cryografts showed that neither the cryopreservation nor the exchange network impaired the distensibility, despite the expected histological changes found in the cryografts. The comparison between intact and cryografts showed that the cryografts would be capable of ensuring a reduced biomechanical mismatch. The cryopreservation and the intercontinental network designed for artery exchange preserved the arterial distensibility. It could be possible to transfer cryografts between Latin America and Europe to be used in cardiovascular surgeries and/or for tissue banking reprocessing, with basic biomechanical properties similar to those of the fresh and/or native arteries.

Regional differences in veins wall viscosity, compliance, energetics and damping: analysis of the pressure-diameter relationship during cyclical overloads.

BACKGROUND: The characterization of the dynamic process of veins walls is essential to understand venous functioning under normal and pathological conditions. However, little work has been done on dynamic venous properties. AIM: To characterize vein compliance (C), viscosity (eta), peak-strain (W St) and dissipated (W(D)) energy, damping (zeta), and their regional differences in order to evaluate their role in venous functioning during volume-pressure overloads. METHODS: In a mock circulation, pressure (P) and diameter (D) of different veins (anterior cava, jugular and femoral; from 7 sheep), were registered during cyclical volume-pressure pulses. From the P-D relationship, C, W(St) and zeta (at low and high P-D levels), eta and W(D) were calculated. RESULTS: For each vein there were P-dependent differences in biomechanical, energetics, and damping capability. There were regional-differences in C, eta), W(St) and W(D) (p<0.05), but not in zeta. CONCLUSION: The regional-dependent differences in dynamics and energetics, and regional-similitude in damping could be important to ensure venous functioning during acute overloads. The lower C and higher W(St) and W(D) found in back-limb veins (femoral), commonly submitted to high volume-pressure loads (i.e. during walking), could be considered relevant to ensure adequate venous system functionality and venous wall protection simultaneously.

[Sleep-wakefulness variations in arterial stiffness: assessment using ambulatory recording of arterial pulse transit time]. / Variaciones sueño-vigilia de la rigidez arterial: estudio mediante registro ambulatorio del tiempo de tránsito de la onda de pulso.

INTRODUCTION AND OBJECTIVES: The incidence of cardiovascular events is related to the sleep-wakefulness cycle. In particular, the magnitude and speed of the changes in hemodynamic variables that occur during transitions between wakefulness and sleep and between sleep and wakefulness are regarded as factors that either predict or determine target organ damage and cardiovascular risk. Although increased arterial stiffness (AS) is associated with the development of cardiovascular abnormalities, it is not known whether there exist any changes in AS that are associated with circadian variations in the incidence of cardiovascular events. The aims of this study were to assess AS in healthy subjects over a 24-hour period, to characterize any differences that occur between sleep and wakefulness, and to investigate any changes in AS that occur during the transition from wakefulness to sleep or from sleep to wakefulness. METHODS: Twenty healthy volunteers with a dipper circadian blood pressure pattern underwent 24-hour ambulatory monitoring of blood pressure, heart rate and AS. In practice, AS was determined using the aorta-brachial pulse transit time and fractional pulsatility indices. Myocardial oxygen consumption was quantified using the double product (DP). An average was calculated for all variables for periods of sleep (23:00 to 06:00) and wakefulness (8:00 to 21:00) and for transitions from wakefulness to sleep (20:00 vs. 02:00) and from sleep to wakefulness (06:00 vs. 10:00 hours). RESULTS: In complete contrast to DP, AS was greater during sleep than wakefulness (P< .05). Moreover, the changes in AS that occurred during transitions from wakefulness to sleep and from sleep to wakefulness were the opposite of those observed in DP (P< .05). CONCLUSIONS: Arterial stiffness was greater during sleep than wakefulness, increased during the transition from wakefulness to sleep, and decreased during the transition from sleep to wakefulness.

Variaciones sueño-vigilia de la rigidez arterial: estudio mediante registro ambulatorio del tiempo de tránsito de la onda de pulso / Sleep­-wakefulness variations in arterial stiffness: assessment using ambulatory recording of arterial pulse transit time

Introducción y objetivos. La incidencia de complicaciones cardiovasculares guarda relación con el ciclo sueño-vigilia. Particularmente, la magnitud y la velocidad de cambio de variables hemodinámicas durante los períodos de transición entre vigilia y sueño se consideran factores pronósticos y/o determinantes de daño de órgano diana y riesgo cardiovascular. Si bien los aumentos en la rigidez arterial (RA) se asocian a desarrollo de alteraciones cardiovasculares, se desconoce si existen variaciones en la RA con relación al patrón circadiano de incidencia de eventos cardiovasculares. El objetivo fue analizar la RA en sujetos sanos durante 24 h y caracterizar las potenciales diferencias entre sueño y vigilia y los cambios en la RA durante la transición de vigilia a sueño y de sueño a vigilia. Métodos. En 20 voluntarios sanos con patrón dipper, se realizó durante 24 h monitorización ambulatoria de presión arterial, frecuencia cardiaca y RA. La RA se evaluó mediante el tiempo de tránsito de la onda de pulso aortobraquial e índices de pulsatilidad fraccional. Se cuantificó el consumo miocárdico de oxígeno mediante el doble producto (DP). Se promediaron las variables para el sueño (de las 23.00 a las 6.00), la vigilia (de las 8.00 a las 21.00) y las transiciones vigilia-sueño (a las 20.00 frente a las 2.00) y sueño-vigilia (a las 6.00 frente a las 10.00). Resultados. Contrariamente al DP, la RA fue mayor durante el sueño que en la vigilia (p < 0,05). La RA varió en forma opuesta al DP durante las transiciones vigilia-sueño y sueño-vigilia (p < 0,05). Conclusiones. La RA fue mayor durante el sueño que en la vigilia, aumentó durante la transición vigilia-sueño y disminuyó durante la transición sueño-vigilia (AU)

Introduction and objectives. The incidence of cardiovascular events is related to the sleep­wakefulness cycle. In particular, the magnitude and speed of the changes in hemodynamic variables that occur during transitions between wakefulness and sleep and between sleep and wakefulness are regarded as factors that either predict or determine target organ damage and cardiovascular risk. Although increased arterial stiffness (AS) is associated with the development of cardiovascular abnormalities, it is not known whether there exist any changes in AS that are associated with circadian variations in the incidence of cardiovascular events. The aims of this study were to assess AS in healthy subjects over a 24-hour period, to characterize any differences that occur between sleep and wakefulness, and to investigate any changes in AS that occur during the transition from wakefulness to sleep or from sleep to wakefulness. Methods. Twenty healthy volunteers with a dipper circadian blood pressure pattern underwent 24-hour ambulatory monitoring of blood pressure, heart rate and AS. In practice, AS was determined using the aorta-brachial pulse transit time and fractional pulsatility indices. Myocardial oxygen consumption was quantified using the double product (DP). An average was calculated for all variables for periods of sleep (23:00 to 06:00) and wakefulness (8:00 to 21:00) and for transitions from wakefulness to sleep (20:00 vs. 02:00) and from sleep to wakefulness (06:00 vs. 10:00 hours). Results. In complete contrast to DP, AS was greater during sleep than wakefulness (P<.05). Moreover, the changes in AS that occurred during transitions from wakefulness to sleep and from sleep to wakefulness were the opposite of those observed in DP (P<.05). Conclusions. Arterial stiffness was greater during sleep than wakefulness, increased during the transition from wakefulness to sleep, and decreased during the transition from sleep to wakefulness (AU)

Regional differences in veins wall viscosity, compliance. energetics and damping: analysis of the pressure-diameter relationship during cyclical overloads

Background: The characterization of the dynamic process of veins walls is essential to understand venous functioning under normal and pathological conditions. However, little work has been done on dynamic venous properties. Aim: To characterize vein compliance (C), viscosity (η), peak-strain (W St) and dissipated (W D) energy, damping (ξ), and their regional differences in order to evalúate their role in venous functioning during volume-pressure overloads. Methods: In a mock circulation, pressure (P) and diameter (D) of different veins (anterior cava, jugular and femoral; from 7 sheep), were registered during cyclical volume-pressure pulses. From the P-D relationship, C, W St and ξ (at low and high P-D leveis), η and W D were calculated. Resulls: For each vein there were P-dependent differences in biomechanical, energetics, and damping capability. There were regional-differences in C, η), W St and W D (p<0.05), but not in ξ. Conclusión: The regional-dependent differences in dynamics and energetics, and regional-similitude in damping could be important to ensure venous functioning during acute overloads. The lower C and higher W St and W D found in back-limb veins (femoral), commonly submitted to high volume-pressure loads (i.e. during walking), could be considered relevant to ensure adequate venous system functionality and venous wall protection simultaneously.