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1.
Ann Vasc Surg ; 70: 506-516, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32890640

RESUMO

BACKGROUND: The research aims to study the effect of circumferential compliance of synthetic vascular prostheses on their healing during implantation in the infrarenal abdominal aorta of pigs. METHODS: In an experiment, 12 pigs were implanted with blood vessel prostheses in the infrarenal abdominal aorta. The prostheses possessed elastic characteristics obtained by a tensile testing machine, and differed in circumferential compliance: rigid (polycaprolactone [PCL]); less compliant than the native aorta (polyurethane [PU]); comparable in compliance to the native aorta (copolymer of vinylidene fluoride with hexafluoropropylene) before (FKM) and after radiation treatment (FKM-γ). The implanted prostheses compliance was measured by aortography during the first 3 days and 1 month after implantation, the condition of the prosthesis capsule was evaluated by macroscopic preparations and histologic examination. RESULTS: Pulsation on PCL prostheses was nonexistent immediately after implantation. On PU prostheses, slight pulsation was noted during the first 3 days and disappeared after 1 month. On FKM prostheses, although pulsation persisted after 1 month, a significant expansion of prostheses was also recorded as a result of fatigue plastic deformation. On FKM-γ prostheses, pulsation comparable in magnitude with aortic pulsation was present 1 month after implantation with no change in the size of the prosthesis. Macroscopic preparations reveal significant differences in the formed connective tissue capsule. The PCL prosthesis capsule is thick, narrowing the lumen of the vessel from the outside. The outer surface of PU prostheses is covered with a thinner uniform fibrous capsule. The inner surface of the FKM and FKM-γ prostheses is covered with a thin layer of smooth whitish tissue. The FKM prosthesis, unlike the FKM-γ prosthesis, is sharply expanded. In all cases, moderate aortic expansion was observed distal to the prosthesis. According to the histologic data, the outer and inner capsules of PCL prostheses are covered with a thick layer of fibrous tissue with signs of productive inflammation and foci of calcification. PU prostheses are surrounded by a thick connective tissue capsule partially endothelialized from the inside; the outer capsule is randomly populated with fibroblastic cells. FKM prostheses have a thin outer capsule where smooth muscle cells are visible, mainly oriented along and across the prosthesis axis; the inner capsule is thin and completely covered with a layer of endothelial cells from the side of the lumen. A layered structure is visible in the prosthesis capsule of FKM-γ, and the fibroblast cells in each layer of the capsule are oriented along or across the prosthesis axis, similar to the structure of a natural arterial vessel. The inner surface of the prosthesis is completely endothelialized. CONCLUSIONS: The healing and degree of inflammation in a capsule of blood vessel prostheses implanted in the infrarenal abdominal aorta of pigs depend on the degree of their circumferential compliance. Although maintaining pulsations, the cellular structure of the capsule is characterized by a greater degree of differentiation and approaches the structure of the native arterial wall.


Assuntos
Aorta Abdominal/cirurgia , Implante de Prótese Vascular/instrumentação , Prótese Vascular , Polímeros/química , Desenho de Prótese , Animais , Aorta Abdominal/diagnóstico por imagem , Aorta Abdominal/patologia , Raios gama , Teste de Materiais , Modelos Animais , Maleabilidade , Poliésteres/química , Polímeros/efeitos da radiação , Poliuretanos/química , Polivinil/química , Sus scrofa , Resistência à Tração , Fatores de Tempo , Remodelação Vascular , Cicatrização
2.
Cardiol Res Pract ; 2019: 4593174, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31885902

RESUMO

The need to simulate the operating conditions of the human body is a key factor in every study and engineering process of a bioengineering device developed for implantation. In the present paper, we describe in detail the interaction between the left ventricle (LV) and our Sputnik left ventricular assist devices (LVADs). This research aims to evaluate the influence of different rotary blood pumps (RBPs) on the LV depending on the degree of heart failure (HF), in order to investigate energetic characteristics of the LV-LVAD interaction and to estimate main parameters of left ventricular unloading. We investigate energetic characteristics of adult Sputnik 1 and Sputnik 2 LVADs connected to a hybrid adult mock circulation (HAMC) and also for the Sputnik pediatric rotary blood pump (PRBP) connected to a pediatric mock circulation (PMC). A major improvement of the LV unloading is observed during all simulations for each particular heart failure state when connected to the LVAD, with sequential pump speed increased within 5000-10000 rpm for adult LVADs and 6000-13000 rpm for PRBP with 200 rpm step. Additionally, it was found that depending on the degree of heart failure, LVADs influence the LV in different ways and a significant support level cannot be achieved without the aortic valve closure. Furthermore, this study expands the information on LV-LVAD interaction, which leads to the optimization of the RBP speed rate control in clinics for adult and pediatric patients suffering from heart failure. Finally, we show that the implementation of control algorithms using the modulation of the RBP speed in order to open the aortic valve and unload the LV more efficiently is necessary and will be content of further research.

3.
J Atr Fibrillation ; 9(5): 1417, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29250264

RESUMO

Atrial fibrillation (AF) is the most common arrhythmia in the population. Still there is no unity in understanding of mechanisms and their influence on catheter ablation results. In our study we tried to evaluate accurate initial quantitative indicators of electromechanical remodeling that can border patients from expected good to expected poor results of catheter ablation. We performed electroanatomical mapping and ablation procedures in 94 patient (45 female) in 2012 with 3-year follow-up period. The target points were left atria surface area, complex fragmentation atrial electrograms (CFAE) duration and surface area. We investigated primary procedure efficacy and initial preoperative patterns of patients in sinus rhythm after 3-year follow-up. Patients with paroxysmal AF had about 3-4 such areas with the median duration of fragmentation 84,5msec and area 10.4cm2. In persistent AF were 5-6 zones, duration of 149 msec and area 22.95cm2. In long standing (LS) persistent AF 6-9 zones with duration up to 200 msec and area close to 30cm2. General efficacy of radiofrequency ablation (RFA) in paroxysmal group was 58,8%, in persistent 33.3% and in LS persistent 12.9% according to Kaplan-Meyer curve with p=0.001. Retrospectively we found that every index in AF recurrence group was 1,5-2 times higher than its equivalent in sinus group. LA surface area was 131.8cm2 vs 103.7cm2 respectively. Median CFAE duration in AF patients was 157msec and 87.5msec in sinus patients. The principal index of CFAE square area was 2,5 times bigger (24.6cm2 vs 10.3cm2 relatively). We concluded that parameters of mechanical (LA volume and surface area) and electrical (CFAE duration and surface area) remodeling have to be defining in tactics and prognosis of catheter ablation in different types of AF. In order to achieve higher efficacy we advise to use stepwise tactic.

4.
Int J Angiol ; 26(3): 148-157, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28804232

RESUMO

This prospective pilot study was designed to investigate the acute hemodynamic effects and clinical applicability of muscular counterpulsation (MCP), a one-shot procedure for biomechanical circulatory support. The study included 17 consecutive patients with coronary artery disease (CAD) and impaired ejection fraction (EF ≤45%) who underwent elective coronary artery bypass grafting (CABG). Patients were divided into control ( n = 7) and treatment ( n = 10) groups. MCP was applied through adhesive skin electrodes to the thighs and calves with a battery-powered, portable, ECG-triggered device for 15 minutes prior to general anesthesia. Standard ECG and invasive hemodynamic data were obtained from all patients. MCP was well tolerated in all patients, with no complications. Patients receiving MCP exhibited better cardiac function as indicated by reduced systemic vascular resistance and an augmented cardiac stroke index (+10%), which was maintained over time. After inducing general anesthesia via endotracheal intubation, the treatment group exhibited a reduced after-load (systemic vascular resistance index -28% and mean arterial pressure -10%) with increased left ventricular efficiency (stroke index/left ventricular stroke work index, +22%). Our findings indicate that MCP method was safe and easy to use in this patient population. In conclusion, a one-shot application of MCP prior to anesthesia was associated with an improvement in cardiac pump function and myocardial contractility.

5.
J Thorac Cardiovasc Surg ; 153(6): 1542-1550, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28314534

RESUMO

OBJECTIVES: To assess safety and clinical performance of a novel bioabsorbable vascular graft in pediatric patients with univentricular cardiac malformation who received surgical correction via an extracardiac cavopulmonary conduit. METHODS: The implanted graft material is designed to attract patient's own cells and proteins, which trigger a cascade of physiological events leading to endogenous tissue restoration. As the graft resorbs progressively after implantation, components of native tissue including collagen, endothelial lining, and capillary blood vessels develop and organize into a natural tissue. Five patients (aged 4-12 years) received this new vascular graft as interposition between the inferior vena cava and the pulmonary artery. They were followed up to 12 months after surgery. The conduit was assessed by echocardiography, computed tomography and magnetic resonance imaging, including 4-dimensional flow. RESULTS: All patients recovered from the procedure without complications. No device-related adverse events were reported. Two patients required interventional occlusion of aortopulmonary collaterals. At 12 months, there was a significant improvement in the patients' general condition. Imaging studies demonstrated anatomical (conduit diameter, length and wall thickness) and functional (blood flow pattern) stability of the bioabsorbable grafts in all patients with no significant changes at 12 months compared with early postoperative data. CONCLUSIONS: Initial clinical experience with a novel absorbable graft underlines the potential of this new material to improve cardiac and vascular surgical procedures. In addition, better biocompatibility may reduce permanent implant-related complications. A longer follow-up is needed to assess the long-term effectiveness of biodegradable vascular grafts, including their ability to grow.


Assuntos
Implantes Absorvíveis , Implante de Prótese Vascular/instrumentação , Prótese Vascular , Derivação Cardíaca Direita/instrumentação , Cardiopatias Congênitas/cirurgia , Artéria Pulmonar/cirurgia , Veia Cava Inferior/cirurgia , Implante de Prótese Vascular/efeitos adversos , Criança , Pré-Escolar , Ecocardiografia , Feminino , Derivação Cardíaca Direita/efeitos adversos , Cardiopatias Congênitas/diagnóstico , Cardiopatias Congênitas/fisiopatologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Estudos Prospectivos , Desenho de Prótese , Artéria Pulmonar/diagnóstico por imagem , Artéria Pulmonar/fisiopatologia , Fatores de Tempo , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Veia Cava Inferior/diagnóstico por imagem , Veia Cava Inferior/fisiopatologia
6.
ASAIO J ; 62(1): 106-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26501917

RESUMO

The world's first implantable total artificial heart was designed by Vladimir Demikhov as a fourth year biology student in Voronezh, Soviet Union, in 1937. As a prototype of his device, Demikhov must have used an apparatus for extracorporeal blood circulation invented by Sergei Bryukhonenko of Moscow. The device was the size of a dog's native heart and consisted of two diaphragm pumps brought into motion by an electric motor. A dog with an implanted device lived for 2.5 hours. In addition to having the prototype, the preconditions for Demikhov's artificial heart creation were his manual dexterity, expertise in animal physiology, and his mechanistic worldview.


Assuntos
Circulação Extracorpórea/história , Coração Artificial/história , Animais , Cães , História do Século XX , U.R.S.S.
8.
Pediatr Cardiol ; 36(1): 71-5, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25099029

RESUMO

In clinical practice, the combination of congenital heart disease (CHD) with malformations of other organs occurs in about 10 % of cases, including chromosomal disease with heart defects, which are observed mainly with certain syndromes. In the Bakoulev SCCS (Moscow, Russian Federation), from 01.2005 to 01.2011, complete atrioventricular septal defect (CAVSD) repair was performed on 163 patients (5.6 ± 3.0 months) with Down Syndrome (DS) using the single-patch (n = 40) and the two-patch (n = 123) methods. The control group consisted of 214 infants aged 6.49 ± 3.03 months with CAVSD and normal karyotype. A retrospective cohort study was made, as well as a comparative analysis of the immediate (up to 30 days) and long-term (12-75 months, at the average of 56 ± 15) results of the repair of CAVSD in infants with DSand normal karyotype/chromosome set (NK). During the hospital treatment period, we registered the following complications: pulmonary hypertensive crises in 6 % (n = 9) of patients with DS and in 10 % (n = 21) of infants with NK, infectious complications in 21% (n = 34) of patients with DS and in 8% (n = 17) of infants with NK. Squeal structures in groups were differentiated. The doses and duration of cardiotonic support in the NK patients were significantly higher in comparison with the DS patients (7.5 ± 2.1 days vs 3.4 ± 1.15 days, p < 0.05). Respiratory infections on the background of immunodeficiency were found more often in the DS group (21% in DS vs 8% in NK, p < 0.05), demanding higher postoperative pulmonary ventilation time in DS patients in comparison with normal infants was required (DS 5.1 ± 2.8 days vs NK 1.7 ± 0.8 days, p < 0.05). In DS infants, abnormalities of the left AV valve (doubling of the mitral valve, single papillary muscle, closely spaced groups of papillary muscles, leaflet or chordal dysplasia, hypoplastic valve ring) occur as statistically significant (8% DS vs 12% NK; p < 0.05) which is rarer than in children having the same defect, but without Down syndrome. Concerning the long-term results, there was no significant difference (Gehan-Wilcoxon test) in actuarial freedom from reoperation after repair of CAVSD between DS and NK groups (p < 0.13). However, the presence of Down Syndrome in patients significantly increases the risk of severe co-morbidities that have a significant impact on the recovery period, as well as on life expectancy even after successful CHD correction.


Assuntos
Síndrome de Down/complicações , Insuficiência da Valva Mitral/etiologia , Insuficiência da Valva Mitral/cirurgia , Estudos de Casos e Controles , Feminino , Seguimentos , Defeitos dos Septos Cardíacos , Humanos , Lactente , Masculino , Reoperação , Estudos Retrospectivos , Resultado do Tratamento
9.
Asian Cardiovasc Thorac Ann ; 23(2): 157-63, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24855279

RESUMO

BACKGROUND: Experience with complete repair of congenital heart defects associated with unilateral absence of a pulmonary artery is limited. The aim of this retrospective study was to present our surgical experience of this complex category of patients, to analyze immediate results of surgical interventions, and to suggest a rational surgical strategy. METHODS: Of 37 patients with a single pulmonary artery who underwent complete repair of associated heart defects, the left or right pulmonary artery was absent in 32 and 5, respectively. The most frequent heart defects were tetralogy of Fallot (n = 25) and ventricular septal defect (n = 8). The median age of these patients was 7.1 years. Preoperative examinations included echocardiography, cardiac catheterization and angiocardiography, with quantitative assessment of the single pulmonary artery. In-hospital parameters of surgical outcome were analyzed. RESULTS: Recorded hospital mortality was 2.7% (1/37). The single death was in a patient with tetralogy of Fallot, agenesis of the left pulmonary artery, and a small diameter of the contralateral pulmonary artery (Nakata index 174 mm(2)·m(-2)). The right-to-left ventricular systolic pressure ratio after complete tetralogy of Fallot repair in patients who survived the operation was 0.58 ± 0.11. CONCLUSIONS: Complete repair of congenital heart defects in patients with unilateral absence of a pulmonary artery is associated with a relatively low risk. If the hilar artery is of adequate size, surgical intervention should attempt restoration of the communication between the disconnected hilar artery and the pulmonary trunk, in addition to repairing the heart defects.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Cardiopatias Congênitas/cirurgia , Artéria Pulmonar/cirurgia , Adolescente , Adulto , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Procedimentos Cirúrgicos Cardíacos/mortalidade , Criança , Pré-Escolar , Feminino , Cardiopatias Congênitas/diagnóstico , Cardiopatias Congênitas/mortalidade , Cardiopatias Congênitas/fisiopatologia , Mortalidade Hospitalar , Humanos , Lactente , Masculino , Complicações Pós-Operatórias/mortalidade , Artéria Pulmonar/anormalidades , Artéria Pulmonar/fisiopatologia , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
16.
Pediatr Cardiol ; 35(7): 1108-15, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24714980

RESUMO

Cardiopulmonary bypass (CPB) reduces coagulation factor levels through hemodilution and consumption. Differences in CPB-induced alterations of factor XIII (FXIII) levels in children with cyanotic and acyanotic congenital heart defects (CHDs) are not well characterized. FXIII activity (determined by Berichrom assay), prothrombin index, activated partial thromboplastin time, and fibrinogen were measured before open heart surgery with CPB and 5 days postoperatively for children older than 3 years with acyanotic (n = 30) and cyanotic (n = 30) CHDs. The preoperative FXIII levels did not differ significantly among the children of the compared groups. The cyanotic patients showed a significantly longer duration of CPB (111.4 ± 45.8 vs 71.5 ± 33.6 min; p = 0.026) and aortic cross-clamp (68.0 ± 27.1 vs 45.4 ± 31.4 min; p = 0.034). The drop in FXIII levels after termination of CPB was more profound for the children with cyanotic CHDs (87.1 ± 13.4 to 49.1 ± 13.2 vs 81.5 ± 12.6 to 58.6 ± 11.1 %, respectively; p = 0.018). The cyanotc patients also were restored to their baseline FXIII levels later than the children with acyanotic CHDs (at 48 vs 24 h). The post-CPB dynamics of the majority of the other coagulation parameters in the compared groups of patients were similar. The cyanotic patients experienced significantly greater postoperative blood loss than the acyanotic patients (12.6 ± 4.9 vs 5.0 ± 2.1 mL/kg; p < 0.001) and were transfused with larger volumes of red blood cells (10.4 ± 6.5 vs 4.2 ± 2.5 mL/kg; p = 0.007). The decrease in FXIII levels after CPB is more profound and lasts longer in children with cyanotic CHDs than in acyanotic patients. The rational strategy of postoperative FXIII replacement therapy for these categories of patients needs to be determined.


Assuntos
Coagulação Sanguínea/fisiologia , Procedimentos Cirúrgicos Cardíacos/métodos , Cianose/sangue , Fator XIII/metabolismo , Cardiopatias Congênitas/cirurgia , Adolescente , Biomarcadores/sangue , Criança , Pré-Escolar , Cianose/etiologia , Cianose/cirurgia , Feminino , Seguimentos , Cardiopatias Congênitas/sangue , Cardiopatias Congênitas/complicações , Humanos , Masculino , Período Pós-Operatório , Prognóstico , Estudos Prospectivos
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