Abstract Polyvinylidene fluoride (PVDF) is a polymer material that exhibits piezoelectricity, which is the ability of certain materials to generate an electric charge in response to applied mechanical stress. Electrospun nanofibers were prepared from a solution with 1800 mg PVDF (18 wt.%) powder dissolved in 7.5 ml of dimethylformamide (DMF) and 2.5 ml acetone. The experimental setup used in the electrostatic deposition process was developed in our laboratory. Atomic Force Microscopy (AFM) showed that the fibers vary from 100 nm to 200 nm. Scanning Electron Microscopy (SEM) measurements showed distributed and well-formed nanofibers, but with few incidences of beads. The Energy Dispersive Spectroscopy (EDX) results showed that all points of the formed nanofibers have very similar chemical compositions, based on carbon and fluorine. Raman and Fourier Transform Infrared (FTIR) Spectroscopic analysis revealed the characteristic bands related to β-phase in the sample, which is responsible for the piezoelectricity of PVDF.

Fundamento: Procedimentos cardiovasculares minimamente invasivos têm sido progressivamente empregados no tratamento das cardiopatias. Objetivo: Descrever as técnicas e os resultados imediatos dos procedimentos minimamente invasivos ao longo de uma experiência de 5 anos. Métodos: Estudo unicêntrico, descritivo e prospectivo, com abordagem quantitativa, no qual 102 pacientes foram submetidos a procedimentos minimamente invasivos de forma direta e de forma videoassistida. Foram avaliadas variáveis clínicas, operatórias e evolução imediata dos pacientes operados. Resultados: Quatorze pacientes foram submetidos a procedimentos minimamente invasivos diretos e 88 a videoassistidos. Entre os submetidos a procedimentos minimamente invasivos diretos, 13 tinham cardiopatia valvar aórtica. Entre os submetidos a procedimentos minimamente invasivos videoassistidos, 43 tinham cardiopatia valvar mitral, 41 defeito do septo interatrial e quatro tumores. Entre os portadores de cardiopatia valvar mitral, foram realizadas 26 trocas e 17 reconstruções valvares. As médias de tempo de clampeamento aórtico, de extracorpórea e do procedimento foram, respectivamente, 91,6 ± 21,8, 112,7 ± 27,9 e 247,1 ± 20,3 minutos entre os submetidos a procedimentos minimamente invasivos diretos. Já entre os submetidos a procedimentos minimamente invasivos videoassistidos, foram 71,6 ± 29, 99,7 ± 32,6 e 226,1 ± 42,7 minutos, respectivamente. Considerando os tempos de terapia intensiva e de internamento, foram 41,1 ± 14,7 horas e 4,6 ± 2 dias entre os submetidos a procedimentos minimamente invasivos diretos e 36,8 ± 16,3 horas e 4,3 ± 1,9 dias entre os videoassistidos. Conclusão: Procedimentos minimamente invasivos foram empregados de duas formas - direta e videoassistida - com segurança no tratamento das cardiopatias valvares, do defeito do septo interatrial e das neoplasias do coração. Constatamos tempos maiores das variáveis operatórias nesses procedimentos. Contudo, a recuperação na fase hospitalar foi rápida, independentemente do acesso e da doença tratada.

Background: Minimally invasive cardiovascular procedures have been progressively used in heart surgery. Objective: To describe the techniques and immediate results of minimally invasive procedures in 5 years. Methods: Prospective and descriptive study in which 102 patients were submitted to minimally invasive procedures in direct and video-assisted forms. Clinical and surgical variables were evaluated as well as the in hospital follow-up of the patients. Results: Fourteen patients were operated through the direct form and 88 through the video-assisted form. Between minimally invasive procedures in direct form, 13 had aortic valve disease. Between minimally invasive procedures in video-assisted forms, 43 had mitral valve disease, 41 atrial septal defect and four tumors. In relation to mitral valve disease, we replaced 26 and reconstructed 17 valves. Aortic clamp, extracorporeal and procedure times were, respectively, 91,6 ± 21,8, 112,7 ± 27,9 e 247,1 ± 20,3 minutes in minimally invasive procedures in direct form. Between minimally invasive procedures in video-assisted forms, 71,6 ± 29, 99,7 ± 32,6 e 226,1 ± 42,7 minutes. Considering intensive care and hospitalization times, these were 41,1 ± 14,7 hours and 4,6 ± 2 days in minimally invasive procedures in direct and 36,8 ± 16,3 hours and 4,3 ± 1,9 days in minimally invasive procedures in video-assisted forms procedures. Conclusion: Minimally invasive procedures were used in two forms - direct and video-assisted - with safety in the surgical treatment of video-assisted, atrial septal defect and tumors of the heart. These procedures seem to result in longer surgical variables. However, hospital recuperation was faster, independent of the access or pathology.

FUNDAMENTO: Para diminuir o trauma cirúrgico em procedimentos cardiovasculares, técnicas Minimamente Invasivas (MI) foram alternativamente introduzidas. OBJETIVO: Comparar o acesso cirúrgico MI com a Esternotomia Mediana (EM) para tratar a cardiopatia valvar mitral (VM) e a Comunicação Interatrial (CIA). MÉTODOS: Estudo prospectivo onde quarenta pacientes foram submetidos a cirurgia para correção de cardiopatia VM ou CIA. Foram divididos em: grupo A (GA) (n = 20), de acesso por minitoracotomia direita com videoassistência, e grupo B (GB) (n = 20), de acesso por EM. Comparamos: tempo de pinçamento aórtico e circulação extracorpórea, tempo de permanência na Unidade de Terapia Intensiva (UTI), tempo de hospitalização e morbidade. RESULTADOS: Quinze pacientes foram submetidos a procedimento VM e 5 a correção de CIA, em cada grupo. Houve nove trocas mitrais (sete bioprotéticas e duas mecânicas) e seis reconstruções no GA, e 10 trocas (todas bioprotéticas) e cinco reconstruções no GB. As médias de tempo de pinçamento aórtico e circulação extracorpórea, em minutos, foram 65,1 ± 29,3 no GA, e 50,2 ± 21,4 no GB (p = 0,074); e 91,8 ± 35 no GA, e 63,7 ± 27,3 no GB (p = 0,008). As médias de tempo de UTI, em horas, foram 51,7 ± 16,3 no GA, e 55,8 ± 17,5 no GB (p = 0,45). Os tempos de hospitalização, em dias, foram 5,2 ± 1 no GA, e 6,4 ± 1,5 no GB (p = 0,009). CONCLUSÃO: O acesso MI para correção da cardiopatia VM e da CIA implicaram em maior tempo de circulação extracorpórea para a finalização do procedimento principal sem, no entanto, afetar a recuperação do paciente. Os pacientes tratados de forma MI tiveram alta hospitalar mais cedo que os pacientes tratados com esternotomia.

BACKGROUND: To decrease the surgical trauma in heart procedures, minimally invasive (MI) techniques were alternatively introduced. OBJECTIVE: To compare MI surgical access with median sternotomy (MS) for the treatment of mitral valve (MV) disease and atrial septal defect (ASD). METHODS: Forty patients underwent surgery for correction of MV disease or ASD. Patients were divided into group A (GA) (n=20), access by right minithoracotomy and video-assistance; and group B (GB) (n=20), access by full MS. Aortic cross-clamp and cardiopulmonary bypass time, intensive care unit (ICU) time, hospital stay and morbidity were compared in this prospective study . RESULTS: Fifteen patients were submitted to MV procedures and five to ASD corrections in each group. There were 9 mitral replacements (7 bioprostetic and 2 mechanical) and 6 repairs in GA, and 10 (all bioprostetic) and five in GB. The mean aortic cross-clamp and cardiopulmonary bypass time, in minutes, were 65.1 ± 29.3 in GA and 50.2 ± 21.4 in GB (p=0.074); and 91.8±35 in GA and 63.7±27.3 in GB ( p=0.008). The mean ICU time, in hours, were 51.7 ± 16.3 in GA and 55.8±17.5 in GB (p=0.45). The in hospital stay, in days, were 5.2 ± 1 in GA and 6.4±1.5 in GB (p=0.009). CONCLUSION: MI access for correction of the MV disease and ASD implicated in a longer cardiopulmonary bypass time for finalization of the main procedure, nevertheless it didn´t affect patient's recuperation. MI treated patients were discharged earlier than sternotomy treated patients.