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1.
Thorac Cardiovasc Surg ; 67(7): 561-563, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30071563

RESUMO

Reconstruction of cardiac valves is associated with reduced mortality, including in multiple valve surgery. However, multiple valve repair is still considered a challenge, even with established techniques. Recently, internal aortic ring annuloplasty has been introduced and could simplify multiple valve reconstruction. This study reports early results with double ring aortic and mitral valve repair. Three patients with bivalvular degenerative regurgitation were managed with combined aortic and mitral valve repair using double rings. Mean (±SD) age was 41 ± 21 years, preoperative left ventricular end-diastolic volume was 119 ± 53 mL/m2, and ejection fraction was 0.50 ± 0.07. Mean aortic ring diameter was 21 mm, and mitral rings averaged 32 mm. No operative mortalities or major complications were observed. No valve-related events occurred. Postoperative echo showed complete resolution of mitral and aortic regurgitation. Postoperative left ventricular end-diastolic volume decreased to 98 ± 10 mL/m2; no left ventricular outflow tract obstruction or significant transvalvular gradients were observed. Postoperative cardiac CTs showed an optimal three-dimensional configuration of aortic and mitral annuloplasty devices. This initial series demonstrated the feasibility and safety of combined aortic and mitral repair with double rings. Clinical and hemodynamic results were promising. Increasing application and more clinical experience with combined aortic and mitral double ring repair seems indicated.


Assuntos
Insuficiência da Valva Aórtica/cirurgia , Valva Aórtica/cirurgia , Implante de Prótese de Valva Cardíaca/instrumentação , Próteses Valvulares Cardíacas , Anuloplastia da Valva Mitral/instrumentação , Insuficiência da Valva Mitral/cirurgia , Valva Mitral/cirurgia , Adulto , Valva Aórtica/diagnóstico por imagem , Valva Aórtica/fisiopatologia , Insuficiência da Valva Aórtica/diagnóstico por imagem , Insuficiência da Valva Aórtica/fisiopatologia , Feminino , Implante de Prótese de Valva Cardíaca/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Valva Mitral/diagnóstico por imagem , Valva Mitral/fisiopatologia , Anuloplastia da Valva Mitral/efeitos adversos , Insuficiência da Valva Mitral/diagnóstico por imagem , Insuficiência da Valva Mitral/fisiopatologia , Desenho de Prótese , Recuperação de Função Fisiológica , Índice de Gravidade de Doença , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
2.
Neth Heart J ; 25(10): 536-544, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28741245

RESUMO

Heart failure has a high prevalence in the general population. Morbidity and mortality of heart failure patients remain high, despite improvements in drug therapy, implantable cardioverter-defibrillators and cardiac resynchronisation therapy. New transcatheter implantable devices have been developed to improve the treatment of heart failure. There has been a rapid development of minimally invasive or transcatheter devices used in the treatment of heart failure associated with aortic and mitral valve disease and these devices are being incorporated into routine clinical practice at a fast rate. Several other new transcatheter structural heart interventions for chronic heart failure aimed at a variety of pathophysiologic approaches are currently being developed. In this review, we focus on devices used in the treatment of chronic heart failure by means of left ventricular remodelling, left atrial pressure reduction, tricuspid regurgitation reduction and neuromodulation. The clinical evaluations of these devices are early-stage evaluations of initial feasibility and safety studies and additional clinical evidence needs to be gathered in appropriately designed clinical trials.

3.
Herz ; 38(5): 460-6, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23864109

RESUMO

Mitral regurgitation (MR) is the most frequent valvular heart disease in developed countries. Surgical repair represents the optimal treatment for severe degenerative MR; however, surgical correction of functional MR is controversial. The Euro Heart Survey showed that up to 50 % of patients with severe MR are today denied surgical treatment. Therefore, new transcatheter techniques have been developed to treat MR with less invasive approaches. Currently, the device with the widest clinical use is the MitraClip System. In this scenario, a multidisciplinary team approach is key in providing optimal individually tailored treatment for patients with MR.


Assuntos
Cateterismo Cardíaco/estatística & dados numéricos , Anuloplastia da Valva Mitral/instrumentação , Anuloplastia da Valva Mitral/estatística & dados numéricos , Insuficiência da Valva Mitral/epidemiologia , Insuficiência da Valva Mitral/cirurgia , Radiografia Intervencionista/estatística & dados numéricos , Instrumentos Cirúrgicos/estatística & dados numéricos , Europa (Continente) , Medicina Baseada em Evidências , Humanos , Insuficiência da Valva Mitral/diagnóstico , Seleção de Pacientes , Prevalência , Desenho de Prótese , Resultado do Tratamento
4.
Minerva Cardioangiol ; 61(3): 295-300, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23681132

RESUMO

MitraClip therapy is emerging as an alternative treatment for primary and secondary mitral regurgitation in high risk patients. A randomized trial has shown safety in selected patients, with efficacy non inferior to surgery in elderly patients with functional mitral regurgitation. Following commercialization, MitraClip therapy is offered to patients very different from the profile of those enrolled in the randomized trial. Several registries are on the way and provide useful preliminary information related to real-world experience with percutaneous mitral valve repair with the MitraClip system.


Assuntos
Idoso Fragilizado , Implante de Prótese de Valva Cardíaca/métodos , Insuficiência da Valva Mitral/terapia , Sistema de Registros , Idoso , Idoso de 80 Anos ou mais , Implante de Prótese de Valva Cardíaca/instrumentação , Humanos , Insuficiência da Valva Mitral/fisiopatologia , Seleção de Pacientes , Ensaios Clínicos Controlados Aleatórios como Assunto , Projetos de Pesquisa , Medição de Risco , Fatores de Risco , Resultado do Tratamento
5.
Minerva Cardioangiol ; 61(2): 229-42, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23492606

RESUMO

Multivalvular heart disease (MHD) accounts for approximately 15% of the patients undergoing valve surgery in the EuroHeart Survey and for 8.6% of all valvular surgical interventions. Most clinical studies on valvular heart disease are focused on single-valve disease and very few data stress the difficulties encountered in the diagnostic assessment and clinical decision making of multiple defects, also concerning the reciprocal hemodynamic influence or the overlap of surgical indications. Many fields related to multiple valve disease are not encountered in the European Guidelines on Valvular Heart Disease (ESC) or the American College of Cardiology/American Heart Association (ACC/AHA). Increasing age and new trends of mixed population have newly aroused interest in multivalvular heart disease in the developed countries, still in need of new clinical insights. According to the high comorbidities of candidates, the appropriate diagnostic framework necessary for the correct diagnosis and best clinical outcome may still be challenging. The paper reviews multivalvular heart disease (except congenital heart disease) from aetiology and background definition to surgical outcome, with special emphasis on echocardiographic assessment and clinical interpretation.


Assuntos
Ecocardiografia , Doenças das Valvas Cardíacas/diagnóstico por imagem , Países Desenvolvidos , Gerenciamento Clínico , Dobutamina , Ecocardiografia/métodos , Teste de Esforço , Testes de Função Cardíaca , Doenças das Valvas Cardíacas/complicações , Doenças das Valvas Cardíacas/epidemiologia , Doenças das Valvas Cardíacas/fisiopatologia , Doenças das Valvas Cardíacas/cirurgia , Hemodinâmica , Humanos , Incidência , Dinâmica Populacional , Lesões por Radiação/diagnóstico por imagem , Lesões por Radiação/fisiopatologia , Radioterapia/efeitos adversos , Cardiopatia Reumática/diagnóstico por imagem , Cardiopatia Reumática/epidemiologia , Volume Sistólico , Disfunção Ventricular Esquerda/complicações , Disfunção Ventricular Esquerda/diagnóstico por imagem , Disfunção Ventricular Esquerda/fisiopatologia , Disfunção Ventricular Direita/complicações , Disfunção Ventricular Direita/diagnóstico por imagem , Disfunção Ventricular Direita/fisiopatologia
6.
Minerva Cardioangiol ; 60(1): 85-93, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22322576

RESUMO

MitraClip system is the only catheter-based device for percutaneous mitral valve repair available for clinical use, after receipt of the CE Mark in 2008, while it is currently under review for FDA approval in the US. To date, over 3500 MitraClip implants have been performed worldwide, mainly in high risk surgical patients. The aim of this review is to review all the current evidences of the MitraClip therapy in an aim to define its clinical role in the treatment of mitral regurgitation (MR).


Assuntos
Anuloplastia da Valva Mitral , Insuficiência da Valva Mitral/cirurgia , Ensaios Clínicos como Assunto , Humanos , Anuloplastia da Valva Mitral/instrumentação
7.
Minerva Cardioangiol ; 59(5): 455-71, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21983306

RESUMO

Mitral regurgitation (MR) is a disabling disease associated with poor prognosis and high incidence of clinical events if left untreated. To reduce the invasiveness of the surgical approach, different types of transcatheter procedures are becoming available. The MitraClip procedure (Abbott Vascular Inc. Menlo Park, CA, USA) is yet the only catheter-based procedure available in clinical practice at the moment. The device has been evaluated in a number of preclinical studies, registries and in FDA approved clinical trials. (EVEREST trial, ACCESS-EU trial). Indication and timing of intervention is a crucial step in the diagnostic-therapeutic pathway of patients with mitral regurgitation. The aim of this review is to clarify the potential of MitraClip in clinical practice, particularly focusing on patient selection for this novel therapy. Patient selection and overall decision making is strongly influenced by anatomical and clinical factors. Decision-making in degenerative MR (DMR) vs. functional (FMR) can be quite different. Generally, MitraClip is effective in treating either type II or IIIb dysfunction (at the moment FMR is the main indication for MitraClip in Europe, according to the ACCESS registry data). The relative role of MitraClip and surgery in the management of patients with MR is still unclear. From the global initial experience, MitraClip therapy could be complementary to surgery in those patients at high risk for surgery who have ideal anatomical characteristics for implantation. The procedure is quite predictable in patients with favorable anatomy. In patients with suboptimal anatomy, if the risk of surgery is too high, MitraClip could be still indicated sometimes. Our preliminary experience suggests that in patients with DMR, the EVEREST anatomical criteria are strong predictors of early and mid-term success. According to it, MitraClip therapy is appropriate in those DMR patients with high surgical risk and ideal anatomy for clip implantation according to the EVEREST criteria. In FMR refractory to medical therapy and resynchronization therapy, MitraClip could be considered as first option therapy, particularly in those patients with comorbidities, or advanced age, being the operative risk of surgery above 5% in this population. In the future, novel devices, improved knowledge, more efficient imaging and transcatheter mitral prosthetic valve implantation may expand the indications to those patients currently not treated by MitraClip for anatomical unsuitability, and may improve the results both in term of early efficacy and long term durability.


Assuntos
Insuficiência da Valva Mitral/cirurgia , Seleção de Pacientes , Previsões , Humanos , Insuficiência da Valva Mitral/complicações , Próteses e Implantes , Desenho de Prótese , Implantação de Prótese/métodos , Técnicas de Sutura , Sístole , Disfunção Ventricular Esquerda/complicações
8.
J Cardiovasc Comput Tomogr ; 13(2): 92-98, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30665879

RESUMO

BACKGROUND: To investigate whether aortic valve calcification (AVC) scoring performed with different workstation platforms generates comparable and thus software-independent results. METHODS: In this IRB-approved retrospective study, we included 100 consecutive patients with symptomatic aortic stenosis undergoing CT prior to transcatheter aortic valve implantation. Two independent observers performed AVC scoring on non-enhanced images with commercially available software platforms of four vendors (GE, Philips, Siemens, 3mensio). Gender-specific Agatston score cut-off values were applied according to current recommendations to assign patients to different likelihood categories of aortic stenosis (unlikely to very likely). Comparative analysis of Agatston scores between the four platforms were performed by using Kruskal-Wallis analysis, Spearman rank correlation, linear regression analysis, and Bland-Altman analysis. Differences in category assignment were compared using Fisher's exact test and Cohen's kappa. RESULTS: For both observers, each workstation platform produced slightly different numeric AVC Agatston scores, however, without statistical significance (p = 0.96 and p = 0.98). Excellent correlation was found between platforms, with r = 0.991-0.996 (Spearman) and r2 = 0.981-0.992 (regression analysis) for both observers. Bland-Altman analyses revealed small mean differences with narrow limits of agreement between platforms (mean differences: 6 ±â€¯128 to 100 ±â€¯179), for inter-observer (mean differences: 1 ±â€¯43 to 12 ±â€¯70), and intra-observer variability (mean differences: 9 ±â€¯42 to 20 ±â€¯96). Observer 1 assigned 11 (kappa: 0.85-0.97) and observer 2 assigned 10 patients (kappa: 0.88-0.95) to different likelihood groups of severe aortic stenosis with at least one platform. Overall, there was no significant difference of likelihood assignment between platforms (p = 0.98 and p = 1.0, respectively). CONCLUSION: While absolute values differ slightly, common commercially available software platforms produce comparable results for AVC scoring, which indicates software-independence of the method.


Assuntos
Estenose da Valva Aórtica/diagnóstico por imagem , Valva Aórtica/diagnóstico por imagem , Valva Aórtica/patologia , Calcinose/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Software , Tomografia Computadorizada por Raios X , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Variações Dependentes do Observador , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Estudos Retrospectivos , Índice de Gravidade de Doença
9.
Circulation ; 101(11): 1255-60, 2000 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-10725284

RESUMO

BACKGROUND: The possibility that enoximone, a nonglycoside, noncatechol, positive inotropic agent, in combination with 2-dimensional echocardiography may predict recovery of myocardial dysfunction after revascularization has not been yet evaluated. METHODS AND RESULTS: Forty-five patients with chronic coronary artery disease and left ventricular dysfunction underwent dobutamine (DE, 5 to 10 microg. kg(-1). min(-1)) and enoximone (EE, 1.5 mg/kg, over 10 minutes) echocardiography. Myocardial wall motion was scored from 1 (normal) to 4 (dyskinesia): an asynergic segment was considered to have contractile enhancement when the score decreased by >/=1 grade. Of 478 asynergic segments, 216 (45%) exhibited functional recovery after revascularization. Dobutamine- and enoximone-induced contractile enhancement was observed in 41% and 46% of segments, respectively. Compared with DE, EE had higher sensitivity (88% versus 79%, P<0.01) and negative predictive value (90% versus 84%, P<0.05) in predicting functional recovery. The specificity (89% versus 90%) and positive predictive value (87% for both EE and DE) were similar. Concordant interpretation of EE and DE findings was found in 85% (406 of 478) of affected segments. Prerevascularization coronary angiography showed that stenosis severity of vessels supplying areas which only improved with enoximone was significantly greater (89.9%) than that of vessels (77.7%) supplying areas that responded to both agents (P<0.02). Both dobutamine and enoximone increased heart rate (16% and 10%, respectively), whereas enoximone did not cause changes in systolic blood pressure that increased by 14% with dobutamine. CONCLUSIONS: Enoximone echocardiography provides a novel and reliable approach for the prediction of functional recovery after revascularization. Compared with dobutamine echocardiography, the test yields higher sensitivity and induces lesser hemodynamic alterations.


Assuntos
Cardiotônicos , Ecocardiografia , Enoximona , Revascularização Miocárdica , Disfunção Ventricular Esquerda/diagnóstico por imagem , Disfunção Ventricular Esquerda/cirurgia , Adulto , Idoso , Dobutamina , Coração/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Contração Miocárdica , Valor Preditivo dos Testes , Prognóstico , Recuperação de Função Fisiológica , Sensibilidade e Especificidade , Sobrevivência de Tecidos , Disfunção Ventricular Esquerda/fisiopatologia , Função Ventricular Esquerda
10.
FEBS Lett ; 185(2): 306-10, 1985 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-3996606

RESUMO

Divinylsulphone-activated agarose to which mercaptoethanol is coupled showed very selective group adsorption of human serum proteins, in particular the immunoglobulins. The adsorption increases markedly in the presence of high concentrations of neutral water-structure forming salts and is distinct from adsorptions based on hydrophobic interaction. A characteristic feature of this new type of adsorbent is the structure of the groups attached to the polymer, P, i.e., R-S-CH2-CH2-SO2-CH2-CH2-O-P, where R is a small aliphatic residue. Our results indicate that the thioether sulphur and the adjacent sulphone group act cooperatively and are apparently necessary to maintain the distinct behaviour of such absorbents.


Assuntos
Proteínas Sanguíneas/análise , Cromatografia de Afinidade/métodos , Polímeros , Sulfonas , Adsorção , Animais , Géis , Humanos , Imunoglobulinas/análise , Ratos
11.
J Thorac Cardiovasc Surg ; 128(1): 117-23, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15224030

RESUMO

BACKGROUND: The efficacy of the St Jude Medical Symmetry aortic connector (St Jude Medical, Inc, St Paul, Minn) for coronary artery bypass is currently debated. Potential drawbacks are the biocompatibility of the endoluminal device, the need for graft manipulation during the procedure, and the 90 degrees offset of the vein graft from the ascending aorta, which may induce graft kinking and abnormal fluid dynamics. In this article, a computational approach was designed to investigate the fluid dynamics pattern at the proximal graft. METHODS: Four models of hand-sewn anastomoses and two models of automated anastomoses were constructed; a finite volume technique was used to simulate realistic graft fluid dynamics, including aortic compliance and proper aortic and graft flow rates. The anastomosis geometry performance was analyzed by calculating time-averaged wall shear stress and the oscillating shear index at the toe and heel regions of the proximal graft. RESULTS: Time-averaged wall shear stress was significantly lower in the hand-sewn anastomosis models than in the two models that simulated the use of the aortic connector (0.38 +/- 0.07 Pa vs 1.32 +/- 0.4 Pa). Higher oscillating shear index values were calculated in the hand-sewn anastomosis models (0.15 +/- 0.02 Pa vs 0.06 +/- 0.02 Pa). CONCLUSIONS: Automated anastomosis geometry is associated with less critical fluid dynamics than with conventional hand-sewn anastomosis: the shape of the proximal graft induces more physiological wall shear stresses and less oscillating flow, suggesting a lower risk of atherosclerotic plaque and intimal hyperplasia as compared with conventional anastomosis geometry. Therefore, the reported early thrombosis and late failure of the St Jude Medical aortic connector anastomoses are not related to unfavorable fluid dynamics.


Assuntos
Aorta/fisiopatologia , Aorta/cirurgia , Valva Aórtica , Implante de Prótese de Valva Cardíaca , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Trombose/epidemiologia , Trombose/etiologia , Veias/fisiopatologia , Veias/cirurgia , Doença Aguda , Anastomose Cirúrgica , Velocidade do Fluxo Sanguíneo/fisiologia , Simulação por Computador , Desenho de Equipamento , Oclusão de Enxerto Vascular/epidemiologia , Oclusão de Enxerto Vascular/etiologia , Oclusão de Enxerto Vascular/fisiopatologia , Humanos , Modelos Cardiovasculares , Complicações Pós-Operatórias/fisiopatologia , Fatores de Risco , Sístole/fisiologia , Trombose/fisiopatologia , Grau de Desobstrução Vascular/fisiologia
12.
J Thorac Cardiovasc Surg ; 126(1): 75-9, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12878941

RESUMO

OBJECTIVE: To describe a novel technique, named "clover," to correct complex post-traumatic tricuspid valve lesions. METHODS: Five patients with severe post-traumatic tricuspid insufficiency underwent valve reconstruction with the clover technique, a new surgical approach that consists of stitching together the middle point of the free edges of the tricuspid leaflets, producing a clover-shaped valve. The mechanism of tricuspid regurgitation was complex in all patients, and right ventricular function was always moderately to severely depressed. An echocardiographic study was performed after cardiopulmonary bypass, at discharge, and at follow-up. RESULTS: Cardiopulmonary bypass time was 32 +/- 6.3 minutes and crossclamp time was 23 +/- 7.4. There was no hospital mortality or morbidity. Intraoperative transesophageal and predischarge transthoracic echocardiography showed perfect results in all patients. No late deaths occurred. At the latest follow-up, extending to 14.2 months (mean 11.3; median 12.4), all patients were asymptomatic (New York Heart Association class I) with trivial (2 patients) or no residual regurgitation (3 patients) on 2-dimensional echocardiogram. No transvalvular gradient was revealed in any patient. A significant reduction of the right ventricular end-diastolic dimensions was noted as well (from 54 +/- 7.1 mm to 40 +/- 7.5 mm, P <.001). CONCLUSIONS: In this preliminary experience, the clover technique increased the feasibility of tricuspid valve repair in case of severe traumatic tricuspid valve insufficiency, leading to very satisfactory mid-term results even in the presence of complex lesions or dilatation and deterioration of the right ventricle.


Assuntos
Implante de Prótese de Valva Cardíaca , Insuficiência da Valva Tricúspide/cirurgia , Valva Tricúspide/lesões , Valva Tricúspide/cirurgia , Adulto , Idoso , Ponte Cardiopulmonar , Ecocardiografia , Feminino , Seguimentos , Humanos , Masculino , Volume Sistólico/fisiologia , Resultado do Tratamento , Valva Tricúspide/diagnóstico por imagem , Ferimentos não Penetrantes/complicações , Ferimentos não Penetrantes/cirurgia
13.
J Thorac Cardiovasc Surg ; 122(4): 674-81, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11581597

RESUMO

OBJECTIVE: The aim of this study is to report our results with the central double-orifice technique used for the treatment of complex mitral valve lesions. METHODS: The central double-orifice repair has been used in 260 patients (mean age, 56 +/- 14.3 years) over a period of 7 years. The mechanism responsible for mitral regurgitation was prolapse of both leaflets in 148 patients, prolapse of the anterior leaflet in 68, prolapse of the posterior leaflet with annular calcification or other unfavorable features in 31, and lack of leaflet coaptation for restricted motion or erosion of the free edge in 13. Degenerative disease was the cause of mitral regurgitation in 80.8% of the patients, rheumatic disease was the cause in 9.6%, endocarditis was the cause in 6.1%, and ischemic disease was the cause in 2.3%. RESULTS: Hospital mortality was 0.7%, and the overall survival at 5 years was 94.4% +/- 2.59%. Thirteen patients required a reoperation (2 early postoperatively and 11 late during the follow-up), for an overall freedom from reoperation of 90.0% +/- 3.37% at 5 years. Freedom from reoperation was lower in patients with rheumatic valve disease and in patients who did not undergo an annuloplasty procedure. CONCLUSIONS: The effectiveness and durability of the central double-orifice technique were assessed in this study. This type of repair can be a useful addition to the surgical armamentarium in mitral valve reconstruction.


Assuntos
Insuficiência da Valva Mitral/cirurgia , Adolescente , Adulto , Idoso , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Procedimentos Cirúrgicos Cardíacos/métodos , Humanos , Pessoa de Meia-Idade , Insuficiência da Valva Mitral/mortalidade , Reoperação , Taxa de Sobrevida
14.
J Appl Physiol (1985) ; 89(1): 314-22, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10904067

RESUMO

In the present paper, the study of the ventricular motion during systole was addressed by means of a computational model of ventricular ejection. In particular, the implications of ventricular motion on blood acceleration and velocity measurements at the valvular plane (VP) were evaluated. An algorithm was developed to assess the force exchange between the ventricle and the surrounding tissue, i.e., the inflow and outflow vessels of the heart. The algorithm, based on the momentum equation for a transitory flowing system, was used in a fluid-structure model of the ventricle that includes the contractile behavior of the fibers and the viscous and inertial forces of the intraventricular fluid. The model calculates the ventricular center of mass motion, the VP motion, and intraventricular pressure gradients. Results indicate that the motion of the ventricle affects the noninvasive estimation of the transvalvular pressure gradient using Doppler ultrasound. The VP motion can lead to an underestimation equal to 12.4 +/- 6.6%.


Assuntos
Simulação por Computador , Coração/fisiologia , Modelos Cardiovasculares , Volume Sistólico/fisiologia , Sístole/fisiologia , Algoritmos , Velocidade do Fluxo Sanguíneo/fisiologia , Humanos , Ultrassonografia Doppler , Função Ventricular
15.
J Biotechnol ; 18(1-2): 41-54, 1991 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1367506

RESUMO

We constructed a series of hybrid plasmids which directed the synthesis of different human growth hormone (hGH) precursor sequences in Bacillus subtilis. In addition to the 191 amino acids of the hormone, the precursors had in common an amino-terminal extension characterized by the presence of a methionine at position 1 and of the tetrapeptide Ile-Glu-Gly-Arg preceding the first residue (Phe) of hGH. The sequence between the methionine and the tetrapeptide was specific for each precursor and, because of the presence of charged residues, conferred particular properties to the molecules. Long homopolymeric tail-containing precursors such as MRRRRRRIILM-IEGR appeared insoluble whereas shorter sequences of the type MRR-IEGR and MEELM-IEGR augmented the solubility of the precursors with respect to Met-hGH. The soluble precursors could be easily purified from the bulk proteins taking advantage of the charged residues present on the N-terminal tail. After purification, the natural hGH was obtained by treating the precursors with the protease Factor Xa which cleaves after the arginine residue of the tetrapeptide IEGR. A protocol for the production and purification of authentic hGH from a strain expressing one of these soluble precursors is reported.


Assuntos
Bacillus subtilis/metabolismo , Hormônio do Crescimento/biossíntese , Sequência de Aminoácidos , Fator Xa/farmacologia , Hormônio do Crescimento/isolamento & purificação , Dados de Sequência Molecular , Recombinação Genética
16.
Eur J Cardiothorac Surg ; 10(10): 867-73, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8911840

RESUMO

OBJECTIVE: The review of six cases of valve repair for traumatic tricuspid regurgitation in our institution and 74 in the literature in order to assess effective methods of treating this lesion. METHODS: Tricuspid valve regurgitation is a rare complication of blunt chest trauma. Optimal treatment for this condition is still controversial ranging from long-term medical therapy to early surgical correction. We followed the cases of six consecutive patients with post-traumatic tricuspid incompetence who were successfully treated with reparative techniques. All patients were male and their ages ranged from 18 years to 42 years. Valve regurgitation was always secondary to blunt chest trauma due to motor vehicle accident. The mechanism of valve insufficiency was invariably anterior leaflet prolapse due to chordal or papillary muscle rupture associated with annular dilatation. Surgical procedures included Carpentier ring implant (5 patients), Bex posterior annuloplasty (1 patient), implant of artificial chordae (4 patients), papillary muscle reinsertion (2 patients), commissuroplasty (1 patient) and "artificial double orifice" technique (1 patient). RESULTS: Tricuspid insufficiency improved in all patients after the correction. No complications were recorded and all patients were asymptomatic at the follow-up. CONCLUSIONS: Since post-traumatic tricuspid regurgitation is effectively correctable with reparative techniques, early operation is recommended to relieve symptoms and to prevent right ventricular dysfunction.


Assuntos
Traumatismos Cardíacos/cirurgia , Insuficiência da Valva Tricúspide/cirurgia , Valva Tricúspide/lesões , Ferimentos não Penetrantes/cirurgia , Adolescente , Adulto , Cordas Tendinosas/lesões , Cordas Tendinosas/cirurgia , Seguimentos , Humanos , Masculino , Músculos Papilares/lesões , Músculos Papilares/cirurgia , Complicações Pós-Operatórias/etiologia , Ruptura , Técnicas de Sutura , Valva Tricúspide/cirurgia
17.
Eur J Cardiothorac Surg ; 17(3): 201-5, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10758376

RESUMO

OBJECTIVES: Mitral-valve repair in Barlow's disease is challenging; conventional techniques are difficult to perform, and there is a high risk of a postoperative suboptimal result. Double-orifice repair has been applied in a standardized approach to treat patients with severe mitral regurgitation and bileaflet prolapse due to Barlow's disease. METHODS: Since 1993, 82 patients with severe mitral regurgitation due to Barlow's disease underwent correction applying the edge-to-edge concept. They were submitted to double-orifice repair in a standardized fashion, suturing the middle portions of both leaflets. RESULTS: There were no hospital deaths. The repair was unsatisfactory in one patient who underwent valve replacement soon after the repair. The mean postoperative valve area was 3.7+/-0.79 cm(2) against a mean preoperative value of 9.2+/-2.1 cm(2). No or mild regurgitation was found in all but three patients who showed moderate residual regurgitation. There were no late deaths. Freedom from reoperation was 86+/-14% at 5 years. At the latest follow-up, all patient but one were New York Heart Association (NYHA) functional class I, and echo-Doppler assessment of valve reconstruction showed stable valve function in all patients. CONCLUSIONS: The double-orifice repair can be used as a standardized approach to treat valve regurgitation due to Barlow disease with low risk and good early and mid-term results.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Insuficiência da Valva Mitral/cirurgia , Prolapso da Valva Mitral/complicações , Técnicas de Sutura , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Insuficiência da Valva Mitral/etiologia
18.
Eur J Cardiothorac Surg ; 15(4): 419-25, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10371115

RESUMO

OBJECTIVES: A 3D computational model has been implemented for the evaluation of the hemodynamics of the double orifice repair. Critical issues for surgical decision making and echo-Doppler evaluation of the results of the procedure are investigated. METHODS: A parametric 3D computational model of the double-orifice mitral valve based on the finite elements model has been constructed from clinical data. Nine different geometries were investigated, corresponding to three total inflow areas (1.5, 2.25 and 3 cm2) and to three orifice configurations (two equal orifices, two orifices of different areas, i.e. one twice as much the other one, and a single orifice). The simulations were performed in transit; the fluid was initially quiescent and was accelerated to the maximum flow rate with a cubic function. For each case, some characteristic values of velocity and pressure were determined: velocities were calculated downstream of each orifice, at the centre of it (Vcen1, Vcen2). The maximum velocity was also determined for each orifice (Vmax1, Vmax2). Maximum pressure drops (deltap(max)) across the valve were compared with the estimations (deltap(Bernoulli)) based on the Bernoulli formula (4 V2). RESULTS: In each simulation, no notable difference was observed between Vcen1 and Vcen2, and between Vmax1 and Vmax2, regardless of the valve configuration. Maximum velocity and deltap(max) were related to the total orifice area and were not influenced by the orifice configuration. Deltap(Bernoulli) calculated with Vmax was well correlated with the deltap(max) obtained throughout the simulations (y = 0.9126x + 0.3464, r = 0.996); on the contrary the pressure drops estimated using Vcen underestimated (y = 0.6757x + 0.3073, r = 0.999) the actual pressure drops. CONCLUSIONS: The hemodynamic behaviour of a double orifice mitral valve does not differ from that of a physiological valve of same total area: pressure drops and flow velocity across the valve are not influenced by the configuration of the valve. Echo Doppler estimation of the maximum velocities is a reliable method for the calculation of pressure gradients across the repaired valve.


Assuntos
Simulação por Computador , Insuficiência da Valva Mitral/fisiopatologia , Insuficiência da Valva Mitral/cirurgia , Modelos Cardiovasculares , Velocidade do Fluxo Sanguíneo , Procedimentos Cirúrgicos Cardíacos/métodos , Ecocardiografia Doppler , Hemodinâmica , Humanos , Insuficiência da Valva Mitral/diagnóstico por imagem , Período Pós-Operatório , Resultado do Tratamento
19.
Eur J Cardiothorac Surg ; 13(3): 240-5; discussion 245-6, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9628372

RESUMO

OBJECTIVE: Repair of mitral regurgitation (MR) is more demanding in case of prolapse of the anterior leaflet, posterior leaflet with calcified annulus, or prolapse of both leaflets. We evaluated a repair which consists of anchoring the free edge of the prolapsing leaflet to the corresponding free edge of the facing leaflet: the 'edge-to-edge' (E-to-E) technique. The correction results in a double orifice valve when the prolapse is in the middle portion of the leaflet and in a smaller valve orifice when the prolapse is close to a commissure. METHODS: Out of 432 patients with MR submitted to valve repair between January 1991 and September 1997, 121 (mean age 56 +/- 15.8 years) underwent E-to-E correction. The most prevalent etiology was degenerative disease (82 patients, 68%). The mechanism of MR was anterior leaflet prolapse (61 patients), posterior leaflet prolapse (24 patients), prolapse of both leaflets (28 patients) and other complex mechanisms (8 patients). In 72 patients, a double orifice was created, the paracommissural repair was done in 49 patients. RESULTS: Hospital mortality was 1.6%. Overall survival was 92 +/- 3.1% at 6 years with 95 +/- 4.8% freedom from reoperation. Mortality was unrelated to the type of repair. Mitral stenosis was never observed after the correction. At the follow-up (mean 2.2 +/- 1.5 years), all patients but 15 are class I or II. Symptoms at the follow-up are not related to residual MR. CONCLUSIONS: Midterm results of this alternative repair technique are promising, considering the high prevalence of complex anatomical lesions. The technique is simple, easily reproducible and rapidly feasible also when mitral exposure is suboptimal.


Assuntos
Insuficiência da Valva Mitral/cirurgia , Técnicas de Sutura , Adolescente , Adulto , Idoso , Procedimentos Cirúrgicos Cardiovasculares/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Insuficiência da Valva Mitral/diagnóstico por imagem , Estudos Retrospectivos , Resultado do Tratamento , Ultrassonografia
20.
Eur J Cardiothorac Surg ; 21(2): 199-204, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11825724

RESUMO

OBJECTIVES: This study was undertaken to evaluate the accuracy of four different risk-adjusted models in predicting mortality in individual patients who are undergoing coronary artery by-pass graft surgery. In the last decade several models to stratify patients before open heart surgery, according to factors affecting mortality, were developed with the aim of retrospectively comparing outcomes of open heart surgery, based on reliable stratification of case-mix, and of prospectively identifying high risk patients as a basis for a meaningful informed consent for patients counseling. METHODS: The pre-operative risk of death was calculated with four different models in 418 consecutive patients who underwent coronary artery by-pass surgery and then compared with the actual outcome. To discriminate patients with favorable and unfavorable outcome, the logistic regression analysis and the areas under the receiver-operating-characteristic curves were applied. The accuracy score was used to evaluate the reliability of each score to predict the individual outcome. RESULTS: Seven deaths (1.7%) were observed within 30 days from the operation, and the overall incidence was similar to that predicted by all models. Only the NBI score was not able to discriminate survivors from patients who will die, and the areas under the curves were 0.596 for the Parsonnet score, 0.861 for the Cleveland Clinic Foundation score, 0.823 for the French score, and 0.806 for the EuroSCORE. The four models were highly accurate (between 0.97 and 0.98) to predict the overall mortality. In seven patients who died the mean predictive scores were very low and ranged between 2.1 and 4.6, but were significantly higher than those of patients who survived (between 1.1 and 2.2). CONCLUSIONS: The four pre-surgical predictive models were similarly able to discriminate favorable vs. unfavorable outcomes and highly accurate to predict overall mortality, but very inaccurate to predict mortality in individual patients.


Assuntos
Ponte de Artéria Coronária/mortalidade , Ponte de Artéria Coronária/métodos , Doença da Artéria Coronariana/cirurgia , Modelos Estatísticos , Adulto , Distribuição por Idade , Idoso , Estudos de Coortes , Doença da Artéria Coronariana/diagnóstico , Doença da Artéria Coronariana/mortalidade , Feminino , Mortalidade Hospitalar/tendências , Humanos , Itália/epidemiologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Cuidados Pré-Operatórios , Probabilidade , Curva ROC , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Sensibilidade e Especificidade , Índice de Gravidade de Doença , Distribuição por Sexo , Análise de Sobrevida
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