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1.
ISRN Cardiol ; 2011: 831062, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22347659

RESUMO

Purpose. To provide an ovine model of ventricular remodeling and reverse remodeling by creating congestive heart failure (CHF) and then treating it by implanting a left ventricular assist device (LVAD). Methods. We induced volume-overload heart failure in 2 sheep; 20 weeks later, we implanted an LVAD and assessed recovery 11 weeks thereafter. We examined changes in histologic and hemodynamic data and levels of cellular markers of CHF. Results. After CHF induction, we found increases in LV end-diastolic pressure, LV systolic and diastolic dimensions, wall thickness, left atrial diameter, and atrial natriuretic protein (ANP) and endothelin-1 (ET-1) levels; ß-adrenergic receptor (BAR) and dystrophin expression decreased markedly. Biopsies confirmed LV remodeling. After LVAD support, LV systolic and diastolic dimensions, wall thickness, and mass, and ANP and ET-1 levels decreased. Histopathologic and hemodynamic markers improved, and BAR and dystrophin expression normalized. Conclusions. We describe a successful sheep model for ventricular and reverse remodeling.

2.
J Heart Lung Transplant ; 29(5): 568-73, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20153967

RESUMO

BACKGROUND: We studied the hemodynamic effects of inducing an artificial pulse in a continuous-flow total artificial heart consisting of 2 axial-flow pumps in a mock circulatory system. METHODS: We varied the amplitude (maximum minus minimum speed), beat rate and systolic duration of the left pump, right pump or both. Mean left and right pump speeds were maintained at 11 and 8 krpm, respectively. Flow rates and arterial and filling pressures were measured in the systemic and pulmonary portions of the mock circulation. Pulse pressure, pulse flow, pulsatility index and surplus hemodynamic energy (SHE) were calculated. The percent change in mean left atrial pressure (LAP) during each induced pulsatility condition was compared with that observed during continuous flow. RESULTS: Systemic pulse pressures of 17 to 61 mm Hg were attained when the left pump was pulsed, regardless of right pump pulsatility settings. The pulse pressure was directly related to the systolic duration and inversely related to the left pump beat rate. SHE ranged from 0.1 to 3.0 mm Hg, and its changes were comparable to those in pulse pressure. The LAP was reduced by left pump pulsation, but a maximal reduction (

Assuntos
Coração Artificial , Hemodinâmica/fisiologia , Modelos Cardiovasculares , Fluxo Pulsátil/fisiologia , Pressão Sanguínea/fisiologia , Humanos , Desenho de Prótese , Circulação Pulmonar/fisiologia , Resistência Vascular/fisiologia
3.
Eur J Heart Fail ; 11(10): 1000-4, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19789404

RESUMO

AIMS: The aim of this study was to analyse the prognostic impact of anaemia in patients receiving long-term left ventricular assist device (LVAD) support. METHODS AND RESULTS: We reviewed the data of 65 consecutive patients who underwent LVAD support for at least 6 months. Anaemia was defined as haemoglobin levels <12.0 g/dL. Follow-up was performed 15 months after implantation. Anaemia was present in 30/65 patients (46%) after 6 months of LVAD support. Anaemic patients had higher levels of pre-implant creatinine (1.8 +/- 0.8 vs. 1.4 +/- 0.5 mg/dL; P = 0.04). The presence of anaemia after 6 months correlated with higher levels of creatinine and blood urea nitrogen and lower levels of albumin. Multivariate Cox proportional hazards regression analysis revealed that levels of haemoglobin <12 g/dL [risk ratio (RR), 8.94; 95% confidence interval (CI), 1.09-73.01; P = 0.04], creatinine >1.4 mg/dL (RR, 5.39; 95% CI, 1.78-16.30; P = 0.003), and albumin <1.5 g/L (RR, 3.23; 95% CI, 1.10-9.51; P = 0.03) were associated with all-cause mortality at 15 months. Long-term survival evaluated by Kaplan-Meier analysis was two times higher in non-anaemic patients after 6 months of LVAD support than in anaemic patients (P = 0.01). CONCLUSION: Anaemia is related to adverse outcomes in patients receiving prolonged LVAD support.


Assuntos
Anemia/etiologia , Eritropoetina/sangue , Insuficiência Cardíaca/cirurgia , Coração Auxiliar/efeitos adversos , Adulto , Fatores Etários , Idoso , Análise de Variância , Anemia/diagnóstico , Anemia/mortalidade , Análise Química do Sangue , Estudos de Coortes , Feminino , Seguimentos , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/mortalidade , Humanos , Incidência , Assistência de Longa Duração , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Probabilidade , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Medição de Risco , Índice de Gravidade de Doença , Fatores Sexuais , Análise de Sobrevida , Fatores de Tempo
4.
ASAIO J ; 55(5): 459-64, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19730003

RESUMO

The interaction of circulating monocytes and platelets may contribute to thrombosis and inflammation in heart failure. We studied platelet and monocyte activation in 15 patients with end-stage heart failure who underwent left ventricular assist device (LVAD) placement. Blood samples were collected before and at 3, 7, 14, 21, 30, 60, 90, and 180 days after LVAD implantation. We used flow cytometry to measure the expression of platelet surface glycoprotein receptors, platelet activation markers, monocyte markers, the formation of platelet complexes with monocytes (MPC), granulocytes, and lymphocytes, and platelet glycoprotein (GP) IIIa (PLA1/A2) polymorphism. The average preoperative percentage of CD62P-positive platelets was 27% +/- 17%; CD63-positive platelets, 9.7% +/- 8.1%; thrombospondin-positive platelets, 9.9% +/- 6.8%; and MPCs, 10.3% +/- 4.3%. No significant changes were noted in the percent of activated platelets with the three markers. Percentage of MPCs increased over time and peaked at day 21 (26.3% +/- 10.6%, p = 0.0028). In about 40% of patients, activation markers remained high up to 60 days after implantation. We found a significant positive correlation between MPC and CD14 (R = 0.60, p = 0.011), and a negative correlation between MPC and P-selectin glycoprotein ligand-1 (PSGL-1) (R = -0.84, p < 0.0001), and between CD14 and PSGL-1 (R = -0.46, p = 0.022) indicating monocyte activation. These results indicate increased platelet and monocyte activation and interactions in patients undergoing long-term LVAD support.


Assuntos
Plaquetas/metabolismo , Comunicação Celular/fisiologia , Coração Auxiliar/efeitos adversos , Leucócitos/metabolismo , Ativação Plaquetária/fisiologia , Feminino , Citometria de Fluxo , Humanos , Masculino , Pessoa de Meia-Idade , Monócitos , Selectina-P , Agregação Plaquetária/fisiologia , Acidente Vascular Cerebral/etiologia
5.
J Heart Lung Transplant ; 27(7): 710-7, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18582798

RESUMO

BACKGROUND: We hypothesized that not all subtypes of alpha- and beta-adrenoreceptors undergo similar upregulation and redistribution in human myocardium after mechanical unloading with an assist device. METHODS: We obtained core biopsy samples of the left ventricle in 19 patients before and after removal of a Jarvik or Thoratec left ventricular assist device (LVAD) to study the effect of mechanical unloading on the distribution of alpha- and beta-adrenoreceptors. Fresh, embedded tissue sections were incubated with receptor blockers and antibodies before the fluorescent labeling of receptors. Images were obtained by fluorescence deconvolution microscopy, and composite tissue renditions were made from the stacked images. Multiple adrenoreceptor subtypes were studied. RESULTS: We saw a reversal of myocyte hypertrophy in all patients, but the upregulation of receptors was not seen in all post-LVAD tissue samples. Furthermore, we noted receptor relocalization from an initial punctate/clumped pattern to a normal homogeneous distribution in many patients. Significant differences were seen in the distribution of beta(2)- and alpha(1)-receptors and in alpha(1A) subtypes. CONCLUSIONS: In this study we show not only the expected reversal of myocyte hypertrophy and the increase in adrenoreceptors after ventricular unloading, but also the relocalization of specific receptor subtypes.


Assuntos
Insuficiência Cardíaca/patologia , Insuficiência Cardíaca/terapia , Miocárdio/patologia , Receptores Adrenérgicos alfa , Receptores Adrenérgicos beta , Adulto , Biópsia por Agulha , Feminino , Transplante de Coração , Coração Auxiliar , Humanos , Masculino , Pessoa de Meia-Idade
6.
ASAIO J ; 54(3): 249-55, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18496274

RESUMO

We developed a mock circulatory loop and used mathematical modeling to test the in vitro performance of a physiologic flow control system for a total artificial heart (TAH). The TAH was constructed from two continuous flow pumps. The objective of the control system was to maintain loop flow constant in response to changes in outflow resistance of either pump. Baseline outflow resistances of the right (pulmonary vascular resistance) and the left (systemic vascular resistance) pumps were set at 2 and 18 Wood units, respectively. The corresponding circuit flow was 4 L/min. The control system consisted of two digital integral controllers, each regulating the voltage, hence, the rotational speed of one of the pumps. The in vitro performance of the flow control system was validated by increasing systemic and pulmonary vascular resistances in the mock loop by 4 and 8 Wood units (simulating systemic and pulmonary hypertension conditions), respectively. For these simulated hypertensive states, the flow controllers regulated circuit flow back to 4 L/min within seconds by automatically adjusting the rotational speed of either or both pumps. We conclude that this multivariable feedback mechanism may constitute an adequate supplement to the inherent pressure sensitivity of rotary blood pumps for the automatic flow control and left-right flow balance of a dual continuous flow pump TAH system.


Assuntos
Coração Artificial , Modelos Cardiovasculares , Animais , Engenharia Biomédica , Desenho de Equipamento , Retroalimentação , Hemodinâmica , Humanos , Hipertensão Pulmonar/fisiopatologia , Hipertensão Pulmonar/cirurgia , Técnicas In Vitro , Matemática
7.
Shock ; 30(6): 675-9, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18461024

RESUMO

To examine the use of mechanical cardiac assist devices in prolonged hemorrhagic shock lasting up to 120 min. We induced hemorrhagic shock in anesthetized calves that were then treated 30 or 120 min later with either conventional fluid and blood resuscitation methods or the implantation of a mechanical assist device in addition to conventional fluid resuscitation. We measured hemodynamic and hematologic variables, inflammatory mediators, end-organ function via biochemical parameters, and survival time. Although cardiac output and blood flow in the left anterior descending artery decreased significantly in all calves at the end of the hemorrhage period, the drop was significantly less severe in calves who received mechanical assistance in addition to fluids. Furthermore, the biochemical profile, indicating liver and kidney function, and survival time were better after hemorrhage in device-treated calves than in conventionally treated calves. Levels of inflammatory mediators, which contribute to cell and organ dysfunction, were increased after hemorrhage, but calves with mechanical devices had less of an increase than did calves treated only with fluids. Our results indicate that the use of a mechanical cardiac assist device in combination with conventional fluid and blood resuscitation methods improves survival and end-organ recovery and decreases the myocardial inflammatory response after prolonged hemorrhagic shock when compared with the sole use of conventional fluid resuscitation techniques.


Assuntos
Coração Auxiliar , Choque Hemorrágico/fisiopatologia , Choque Hemorrágico/terapia , Animais , Débito Cardíaco , Bovinos , Modelos Animais de Doenças , Feminino , Hidratação/métodos , Distribuição Aleatória , Ressuscitação/métodos
8.
Artif Organs ; 32(6): 427-32, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18422799

RESUMO

Left ventricular assist device (LVAD) implantation in end-stage heart failure patients is frequently associated with hemorrhagic complications requiring reoperation. The preoperative coagulopathic profile includes prolonged prothrombin time (PT), partial thromboplastin time (PTT), and bleeding time; platelet dysfunction; decreased coagulation factor activity; and increased inflammatory markers. We compare outcomes in LVAD patients treated with preoperative plasma exchange with concurrent, nonrandomized control patients. We reviewed data from 68 consecutive elective patients who received LVADs at our institution. Thirty-five received LVADs after preoperative plasma exchange (replacement of one plasma volume of fresh frozen plasma), and 33 received LVADs without plasma exchange. Groups were comparable in age, sex, body weight, New York Heart Association class, intra-aortic balloon pump insertion, cardiac index, pulmonary capillary wedge pressure, creatinine, total bilirubin, hemoglobin levels, PT, international normalized ratio, PTT, and platelet count. Early mortality was lower in the plasma exchange group (0% [0/35] vs. 18% [6/33], P = 0.026), and postoperative chest tube drainage decreased by 33% (P = not significant). Blood transfusion requirements were similar. Perioperative mortality decreased in patients treated with plasma exchange before LVAD implantation.


Assuntos
Procedimentos Cirúrgicos Cardíacos/métodos , Coração Auxiliar , Troca Plasmática/mortalidade , Cuidados Pré-Operatórios , Adulto , Idoso , Bilirrubina/análise , Tempo de Sangramento , Ponte Cardiopulmonar , Estudos de Coortes , Creatinina/análise , Feminino , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/mortalidade , Hemoglobinas/análise , Humanos , Masculino , Pessoa de Meia-Idade , Tempo de Tromboplastina Parcial , Hemorragia Pós-Operatória/complicações , Tempo de Protrombina
9.
J Card Fail ; 14(2): 140-4, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18325461

RESUMO

BACKGROUND: In retrospective studies, statin therapy has been related to decreased incidence of sudden cardiac death (SCD) in heart failure. We sought to prospectively investigate a relation between atorvastatin therapy and SCD in patients with advanced chronic heart failure. METHODS AND RESULTS: We enrolled 110 patients with heart failure with a left ventricular ejection fraction less than 30% and cholesterol level greater than 150 mg/dL. Fifty-five patients were randomized to atorvastatin (10 mg/day) (statin group); the remaining 55 patients received no statins (controls). Patients were followed for 1 year. At baseline, the two groups did not differ in age, sex, left ventricular ejection fraction, cholesterol, B-type natriuretic peptide, heart rate variability, or QT variability. During follow-up, 29 patients died (26%) and 2 patients (2%) underwent heart transplantation. Of the 29 deaths, 13 were attributed to pump failure, 15 were attributed to SCD, and 1 was attributed to noncardiac causes. All-cause mortality was lower in the statin group (9/55, 16%) than in controls (20/55, 36%) (P = .017). The same was true of the SCD rate (3/55 [5%] vs. 12/55 [22%], P = .012), but not of the pump failure (5/55 [9%] vs. 8/55 [15%], P = .38). SCD-free survival was 2.3-times higher in the statin group than in controls (P = .01). CONCLUSIONS: Atorvastatin therapy seems to be associated with decreased incidence of SCD in patients with advanced chronic heart failure. Larger studies are ongoing to confirm this hypothesis.


Assuntos
Morte Súbita Cardíaca/prevenção & controle , Insuficiência Cardíaca/fisiopatologia , Ácidos Heptanoicos/uso terapêutico , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Pirróis/uso terapêutico , Atorvastatina , Progressão da Doença , Feminino , Indicadores Básicos de Saúde , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/mortalidade , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Peptídeo Natriurético Encefálico/sangue , Estudos Prospectivos , Fatores de Risco , Volume Sistólico
10.
Ann Thorac Surg ; 85(1): 56-8, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18154778

RESUMO

BACKGROUND: Some contemporary surgical treatments for atrial fibrillation involve creating only a subset of the lesions made in the classic Cox Maze procedure. This subset often consists of pulmonary vein isolation and partial cardiac denervation. Orthotopic heart transplantation, by necessity, results in pulmonary vein isolation, albeit with total cardiac denervation. Although postoperative atrial fibrillation (POAF) and atrial fibrillation may differ in cause, they have similar underlying mechanisms and often respond to the same treatments. Therefore, we reviewed the incidence of POAF in heart transplant recipients to assess the antiarrhythmic effects of pulmonary vein isolation and cardiac denervation. METHODS: We reviewed the charts of 498 consecutive patients who underwent orthotopic heart transplantation at a single institution during a 15-year period. RESULTS: Twenty-seven patients (5.4%) experienced POAF within 60 days of transplant. In 9 of these patients, POAF occurred within 2 weeks of a biopsy-proven transient rejection episode; excluding these patients from the analysis revealed a non-rejection-associated POAF rate of 18 of 489 patients (3.7%). CONCLUSIONS: Despite the long ischemic times, extensive manipulation of the transplanted heart, and the postoperative administration of proarrhythmic inotropic agents that cardiac transplantation typically involves, this procedure is associated with a low incidence of POAF, particularly if patients in whom rejection and POAF were temporally related are excluded. These findings suggest that complete cardiac denervation and pulmonary vein isolation protect heart transplant recipients from POAF, thus supporting the notion that similar lesions may be useful in the treatment of other types of atrial fibrillation.


Assuntos
Fibrilação Atrial/diagnóstico , Fibrilação Atrial/epidemiologia , Transplante de Coração/efeitos adversos , Adulto , Fibrilação Atrial/etiologia , Estudos de Coortes , Eletrocardiografia , Feminino , Seguimentos , Rejeição de Enxerto , Sobrevivência de Enxerto , Transplante de Coração/métodos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Probabilidade , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Índice de Gravidade de Doença , Taxa de Sobrevida , Resultado do Tratamento
11.
Tex Heart Inst J ; 35(4): 447-50, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19156239

RESUMO

Cardiac support with a ventricular assist device is among the few treatments for heart-failure patients who have profound cardiogenic shock unresponsive to vasopressors and intra-aortic balloon pumps. The TandemHeart percutaneous ventricular assist device can provide temporary support until another device can be placed or a donor heart becomes available. We examined the TandemHeart's effect on cardiac index, central venous pressure, mixed venous oxygen saturation, creatinine, mean arterial pressure, urine output, and 30-day mortality rate in 5 heart-failure patients (2 with nonischemic and 3 with ischemic cardiomyopathy; mean preoperative left ventricular ejection fraction, 0.17 +/- 0.056). Two patients were undergoing cardiopulmonary resuscitation when the device was inserted. The average duration of TandemHeart support was 7.6 +/- 3.2 days; all patients were successfully bridged to transplantation. The TandemHeart improved the cardiac index (1.9 +/- 0.3 vs 3.5 +/- 0.8 L/[min.m2], P= 0.01), mean arterial pressure (69 +/- 12.5 vs 91 +/- 4.3 mmHg, P=0.009), mixed venous oxygen saturation (45.4 +/- 14.3 vs 71.4 +/- 7.5, P=0.009), and urine output (1,861 +/- 988 vs 4,314 +/- 1,346 mL/hr, P=0.01). The device decreased central venous pressure (21.2 +/- 7.4 vs 12.8 +/- 5.9 mmHg, P=0.02) and pressor requirements (2.4 +/- 1.1 vs 1.0 +/- 0.7 agents, P=0.02). Average long-term follow-up after heart transplantation was 8.4 +/- 9.9 months, with no deaths. We conclude that the TandemHeart can provide hemodynamic support for patients with profound, refractory cardiogenic shock. Furthermore, the device can bridge patients to cardiac transplantation and can be placed percutaneously, without invasive surgery.


Assuntos
Angioplastia Coronária com Balão , Cardiomiopatias/complicações , Insuficiência Cardíaca/cirurgia , Coração Auxiliar , Choque Cardiogênico/prevenção & controle , Adulto , Implante de Prótese Vascular , Débito Cardíaco , Cardiomiopatias/terapia , Insuficiência Cardíaca/terapia , Transplante de Coração , Hemodinâmica , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Volume Sistólico
12.
J Heart Lung Transplant ; 26(11): 1209-11, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18022090

RESUMO

In this report we describe the insertion of a felt plug into the sewing ring attached to the left ventricular apex after explantation of a left ventricular assist device. This technique may be faster and simpler than standard explantation techniques and may result in less distortion of left ventricular geometry.


Assuntos
Procedimentos Cirúrgicos Cardíacos/métodos , Cardiomiopatias/terapia , Remoção de Dispositivo/métodos , Coração Auxiliar , Adulto , Procedimentos Cirúrgicos Cardíacos/instrumentação , Remoção de Dispositivo/instrumentação , Ecocardiografia , Ventrículos do Coração/diagnóstico por imagem , Humanos , Masculino , Esterno/cirurgia , Função Ventricular
13.
J Card Fail ; 13(7): 517-20, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17826641

RESUMO

BACKGROUND: The ventricular partitioning device (VPD) (Cardiokinetix Inc., Redwood City, Calif) is a novel device that is deployed percutaneously in the left ventricle in patients with anteroapical regional wall motion abnormalities after a myocardial infarction (MI) to partition the ventricle and segregate the dysfunctional region. In this case report we present the first implantation of the VPD in a human, with a 12-month efficacy and safety follow-up. METHODS AND RESULTS: A 48-year-old man had an anterior MI in 2004. A coronary angiogram showed an occlusion of the proximal segment of the left anterior descending artery with no stenosis on other major epicardial vessels. Echocardiography revealed a dilated left ventricle (62 mm) with anteroapical wall motion abnormalities, no apical thrombus, a calculated ejection fraction of 26.8% (by Simpson biplane formula), and an end-systolic volume index (ESVi) of 76.8 mL/m(2). The VPD implant was delivered percutaneously from the femoral artery by the standard techniques for left-sided heart catheterization. The postimplantation course was uneventful. Echocardiography on discharge showed the VPD implanted at the apex, with a left ventricular ejection fraction of 30.9% and an ESVi of 57.2 mL/m(2). Left ventricular ejection fraction and ESVi remained improved during the 12-month follow-up. CONCLUSION: This case report demonstrates that VPD implantation in this particular patient was feasible and that it may provide a nonsurgical approach to prevent or reverse left ventricle remodeling.


Assuntos
Baixo Débito Cardíaco/terapia , Próteses e Implantes , Cateterismo Cardíaco , Baixo Débito Cardíaco/diagnóstico por imagem , Doença Crônica , Angiografia Coronária , Ecocardiografia , Desenho de Equipamento , Segurança de Equipamentos , Estudos de Viabilidade , Seguimentos , Ventrículos do Coração , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
14.
Heart Fail Clin ; 3(3): 259-65, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17723934

RESUMO

In patients who have end-stage heart failure, medical therapy is of limited use, and heart transplantation is frequently not an option because of the shortage of donor hearts. Two new treatment options, left ventricular assist devices (LVADs) and implantable cardiac resynchronization therapy (CRT) devices, can improve survival and quality of life in patients who have heart failure. Both types of devices are easy to implant. However, LVADs carry the risk of infection and mechanical failure, and CRT is ineffective in a substantial proportion of patients who have heart failure. Therefore, methods must be devised to identify patients who have heart failure who are likely to benefit from these devices. Data suggest that early LVAD implantation, before end-stage heart failure develops, is critical to slowing or reversing disease progression. Similarly, in indicated patients who have less advanced disease, CRT may be particularly beneficial.


Assuntos
Cardioversão Elétrica/métodos , Insuficiência Cardíaca/cirurgia , Coração Auxiliar , Disfunção Ventricular Esquerda/cirurgia , Progressão da Doença , Insuficiência Cardíaca/patologia , Humanos , Seleção de Pacientes , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Análise de Sobrevida
15.
J Heart Lung Transplant ; 26(8): 815-8, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17692785

RESUMO

BACKGROUND: Limited data exist about the long-term effects of continuous-flow vs pulsatile-flow left ventricular assist devices (LVADs) on end-organ function. METHODS: We reviewed the data of patients who underwent LVAD implantation at our institution between 1989 and 2004 and who were supported for >6 months. The continuous-flow (C-LVAD) group included 12 patients bridged to transplant with either a Jarvik 2000 or a Thoratec HeartMate II LVAD. The pulsatile (P-LVAD) group included 58 patients supported by a Thoratec HeartMate I LVAD. Follow-up was up to 15 months after LVAD implantation. Average duration of LVAD support was 370 +/- 182 days (range 180 to 754) for the C-LVAD group and 315 +/- 111 days (range 180 to 1,334) for the P-LVAD group. RESULTS: Patients from both groups were comparable for age, gender, body weight, cardiac index, ejection fraction, creatinine, blood urea nitrogen, creatinine clearance, albumin, total bilirubin, and transaminase levels before implantation. C-LVAD patients had a lower pre-operative hemoglobin than did P-LVAD patients (10.5 +/- 1.7 g/dl vs 12.2 +/- 1.9 g/dl; p = 0.01). In both groups, albumin, blood urea nitrogen, creatinine, creatinine clearance, total bilirubin, and transminase levels either improved or stayed within the normal range at 6, 9, 12, and 15 months after LVAD implantation. Four of the 12 C-LVAD patients and 28 of the 58 P-LVAD patients underwent cardiac transplantation. Actuarial survival, censored for transplant, at 9, 12, and 15 months was 90% for the C-LVAD group and 88%, 78%, and 74% for the P-LVAD group (p = not statistically significant). CONCLUSIONS: On the basis of these data, it appears that continuous- and pulsatile-type LVADs provide adequate blood flow to maintain proper end-organ function during prolonged circulatory support.


Assuntos
Insuficiência Cardíaca/fisiopatologia , Coração Auxiliar , Implantação de Prótese/instrumentação , Função Ventricular Esquerda/fisiologia , Feminino , Seguimentos , Insuficiência Cardíaca/mortalidade , Insuficiência Cardíaca/cirurgia , Transplante de Coração , Ventrículos do Coração , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Volume Sistólico/fisiologia , Taxa de Sobrevida , Fatores de Tempo , Resultado do Tratamento , Listas de Espera
16.
Perfusion ; 22(1): 63-6, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17633137

RESUMO

Measurement of systemic blood flow is of crucial importance in patients on mechanical circulatory support (MCS). We reported the case of a 65-year-old female patient in severe cardiogenic shock undergoing left (Jarvik 2000 axial flow pump) and right (Levitronix-Centrimag centrifugal pump) ventricular assist device implant. Evaluation of blood flow was obtained by ultrasonic flowmetry, continuous thermodilution technique, and pressure recording analytical method (PRAM). This pulse contour system allows beat-by-beat systemic blood flow assessment from the analysis of radial artery pressure waveform. At a Jarvik pump speed < or = 10000 rotations per minutes (rpm), thermodilution and PRAM showed similar blood flow values. At a Jarvik pump speed > or = 11000 rpm, the aortic valve did not open and PRAM did not provide blood flow values due to nonpulsatile blood flow. The present paper describes the first experience with PRAM in a single patient on MCS. Further studies are required to assess the validity of PRAM as an additional monitoring system in the setting of ventricular assist device support.


Assuntos
Velocidade do Fluxo Sanguíneo , Coração Auxiliar , Fluxo Pulsátil , Idoso , Feminino , Humanos , Artéria Radial
17.
Am Heart J ; 153(6): 932-40, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17540193

RESUMO

BACKGROUND: Urgent heart transplant candidates classified as United Network for Organ Sharing status 1B who require continuous infusions of inotropic agents for hemodynamic stability often have hemodynamic, electrical, or multisystem decompensation. This multicenter trial will study both traditional safety and efficacy parameters and the physiologic mechanisms of benefit of the addition to conventional therapy of nesiritide, a recombinant analog of brain-type natriuretic peptide, in this population. METHODS: TMAC is a prospective, randomized, parallel, multicenter, double-blind, placebo-controlled study in patients awaiting heart transplantation who meet United Network for Organ Sharing status 1B criteria (N = 120) and receive continuous dobutamine or milrinone through a double-lumen central catheter for at least 3 consecutive days before randomization. Patients will receive standard care and continuous intravenous inotrope therapy plus a 28-day continuous infusion of nesiritide or placebo. There will be up to 6 months of follow-up. Primary efficacy end point will be days alive after treatment without renal, hemodynamic, or electrical worsening at completion. Secondary analyses will evaluate effects on hemodynamics, echocardiographic parameters, endogenous brain-type natriuretic peptide levels, modification of diet in renal disease-calculated glomerular filtration rate, and all-cause and cardiovascular mortality. Two mechanistic substudies will evaluate the effect on iohexol-determined glomerular filtration rate and assess changes in lung mechanics. CONCLUSION: This investigation will provide key data for clinical profiles of heart transplant candidates bound to inotropic support. It will investigate the efficacy and safety (especially renal) of nesiritide and provide mechanistic insight into benefits of its use for the relief of breathlessness.


Assuntos
Cardiotônicos/uso terapêutico , Insuficiência Cardíaca/tratamento farmacológico , Transplante de Coração , Natriuréticos/uso terapêutico , Peptídeo Natriurético Encefálico/uso terapêutico , Dobutamina/administração & dosagem , Método Duplo-Cego , Ecocardiografia , Definição da Elegibilidade , Insuficiência Cardíaca/classificação , Insuficiência Cardíaca/mortalidade , Insuficiência Cardíaca/cirurgia , Humanos , Infusões Intravenosas , Seleção de Pacientes , Cuidados Pré-Operatórios , Projetos de Pesquisa , Tamanho da Amostra , Índice de Gravidade de Doença , Taxa de Sobrevida , Resultado do Tratamento
18.
ASAIO J ; 53(3): 392-6, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17515735

RESUMO

We evaluated the effects of the Levitronix UltraMag pediatric ventricular assist system on healthy animals during 29- to 90-day periods by assessing hemocompatibility and hepatic and renal functions while operating the device in a flow range suitable for pediatric patients. Nine lambs (weight, 15 to 24 kg) received the Levitronix UltraMag with an outflow cannula anastomosed to the descending aorta and an inflow cannula inserted into the left ventricular apex. Pump function data were collected at 1-hour intervals, and postoperative hematology and clinical chemistry tests were performed weekly throughout the study. Complete necropsy and histopathologic examinations were performed at study termination. Pump and circuit were thoroughly inspected for evidence of thrombi. All animals reached the scheduled endpoint of 29 to 90 days without device-related problems. Mean flow was maintained at 1.14 +/- 0.19 L/min. Hematologic values were within normal range in all animals except in one lamb that had a severe hemolytic reaction after cefazolin sodium administration. In all animals, serum glutamic-oxaloacetic transaminase and creatinine kinase levels increased after surgery but gradually returned to normal limits within 1 week. Postmortem examination of the explanted organs revealed small infarcted areas in five lamb kidneys, but renal function was unaffected. All other major organs were unremarkable. In one explanted pump (a 30-day study), a small thrombus was seen within the impeller blade. The other eight pumps were free of thrombus. The Levitronix UltraMag successfully operated in pediatric flow ranges without device-related adverse events.


Assuntos
Débito Cardíaco , Cateterismo/métodos , Coração Auxiliar , Implantação de Prótese , Animais , Tamanho Corporal , Criança , Coração Auxiliar/efeitos adversos , Hematócrito , Hemoglobinas , Humanos , Testes de Função Renal , Testes de Função Hepática , Modelos Animais , Contagem de Plaquetas , Ovinos , Trombose/etiologia
19.
Tex Heart Inst J ; 34(4): 406-11, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18172519

RESUMO

In this study, long-term (90-day) hemocompatibility and end-organ effects of a centrifugal left ventricular assist device (the Heartware HVAD) were evaluated in 6 healthy sheep. The device was implanted into the left ventricular apex on beating hearts. The outflow graft of each device was anastomosed to the descending aorta. None of the sheep received anticoagulation or antiaggregation medication during the study. Hematologic and biochemical tests of liver and kidney function were performed pre-operatively (baseline) and throughout the study. Data associated with pump function were collected continuously until 90 +/- 1 days of support, at which time the sheep were humanely killed, and the end-organs were examined macroscopically and histopathologically. Hematologic and biochemical test results were within normal limits during the study period. There were no significant complications. Postmortem examination of the explanted organs revealed no evidence of ischemia or infarction, except in 2 sheep, in which small foci of infarction were detected in each of their left kidneys. There was no significant device failure. In all sheep, the pump's inflow and outflow conduits were free of thrombus. During the 90-day study, the HeartWare HVAD showed exceptional hemocompatibility and reliability, both of which are crucial to the clinical success of any implantable left ventricular assist device.


Assuntos
Materiais Biocompatíveis , Insuficiência Cardíaca/cirurgia , Coração Auxiliar , Implantação de Prótese/instrumentação , Animais , Modelos Animais de Doenças , Contagem de Eritrócitos , Seguimentos , Insuficiência Cardíaca/sangue , Ventrículos do Coração/patologia , Hematócrito , Desenho de Prótese , Reprodutibilidade dos Testes , Ovinos
20.
Congest Heart Fail ; 12(6): 297-301, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17170581

RESUMO

Anemia is prevalent in patients with chronic heart failure and is associated with worse symptoms and poor prognosis. The authors reviewed the charts of all patients (N=467) treated at Texas Heart Institute from January 2000 to October 2003, during which time a clinical protocol offered treatment with erythropoiesis-stimulating proteins. Post-treatment, the authors observed a significant increase in mean +/- SD hemoglobin, from 9.9+/-1.1 g/dL to 11.7+/-1.5 g/dL (P<.0001), improvement of renal function (a decrease in mean levels of creatinine and blood urea nitrogen), and fewer hospital admissions (1.0+/-1.4 vs 1.8+/-1.6; P=.0003) without an increase in adverse clinical events, compared with pretreatment and compared with an untreated control group. These results suggest a potential benefit of anemia treatment with recombinant erythropoiesis-stimulating proteins in patients with chronic heart failure.


Assuntos
Anemia/tratamento farmacológico , Eritropoetina/uso terapêutico , Insuficiência Cardíaca/complicações , Idoso , Anemia/sangue , Anemia/etiologia , Feminino , Insuficiência Cardíaca/sangue , Insuficiência Cardíaca/tratamento farmacológico , Hematínicos , Hemoglobinas/análise , Hospitalização/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Peptídeo Natriurético Encefálico/sangue , Proteínas Recombinantes , Estudos Retrospectivos
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