Hemodynamic performance and inflammatory response during the use of VAD-InCor as a bridge to transplant

FUNDAMENTO: O transplante cardíaco enfrenta o grave problema da escassez de doadores. Estima-se que entre 20% e 40% dos pacientes falecem na fila de espera. Para esses pacientes, a utilização de dispositivos de assistência circulatória é, muitas vezes, a única possibilidade de sobrevivência durante a espera do doador. No Brasil, não existe nenhum programa regular de utilização desses dispositivos como ponte para transplante. OBJETIVO: Avaliar o desempenho hemodinâmico e a resposta inflamatória durante a utilização do DAV-InCor como ponte para transplante. MÉTODOS: Entre outubro de 2003 e abril de 2006, 11 pacientes, indicados em caráter de prioridade para o transplante cardíaco, evoluíram em choque cardiogênico refratário. O implante do DAV-InCor foi realizado em sete pacientes. O diagnóstico etiológico foi cardiopatia chagásica em cinco pacientes e cardiomiopatia dilatada idiopática em dois. RESULTADOS: A assistência mecânica ao ventrículo esquerdo foi mantida nos sete pacientes por períodos entre 14 e 42 dias (média 26,2). O desempenho hemodinâmico foi adequado, com a normalização do índice cardíaco, dos níveis de saturação venosa de O2 e do lactato. O transplante foi realizado em dois pacientes, os outros cinco faleceram por infecção sistêmica ou falência de múltiplos órgãos. CONCLUSÃO: O desempenho do DAV-Incor, no comportamento hemodinâmico dos pacientes estudados, foi adequado para a manutenção de uma condição circulatória satisfatória durante o período estudado. Houve melhora dos parâmetros de perfusão tecidual e manutenção de sinais de resposta inflamatória sistêmica. Houve alta incidência de complicações; contudo, não foram demonstradas complicações relacionadas ao dispositivo que comprometam a segurança da utilização do mesmo.BACKGROUND: Cardiac transplantation faces the serious problem of lack of donors and it is estimated that 20 to 40% of the patients die while waiting for heart transplantation. For these patients, the use of mechanical circulatory assist devices is the only choice of survival while waiting for a donor. In Brazil, the experience with mechanical circulatory support is limited and there is no regular program regarding the use of these devices as a bridge to heart transplantation. OBJECTIVE: To evaluate the hemodynamic performance and the systemic inflammatory response during the clinical use of the InCor-type ventricular assist device (VAD-InCor) as a bridge to heart transplantation. METHODS: Between October 2003 and April 2006, 11 patients in the waiting list for heart transplantation presented hemodynamic deterioration due to refractory cardiogenic shock. Seven of these patients were submitted to VAD-InCor implantation for left ventricular assistance. The etiologic diagnosis was Chagas' disease in 5 patients and idiopathic dilated cardiomyopathy in 2. RESULTS: The duration of left ventricular assistance ranged from 14 to 42 days (mean 26.2 days). During this period, the hemodynamic performance of the DAV-InCor was adequate to support a normal hemodynamic state. There was normalization of central venous oxygen saturation and serum lactate. Two patients were submitted to heart transplantation, while the other 5 patients died under assistance due to infection and multiple organ failure. CONCLUSION: The performance of the VAD-InCor, in the hemodynamic behavior of the studied patients, was adequate for the maintenance of a satisfactory circulatory state during the studied period. There was improvement in the tissue perfusion parameters and maintenance of systemic inflammatory response signs. There was a high incidence of complications; however, complications related to the device, which could compromise the safety of its use, were not demonstrated.FAPESPCNP

Prospects in Lyophilization of Bovine Pericardium

Almost 30 years after the introduction of heart valve prostheses patients worldwide are benefiting from the implant of these devices. Among the various types of heart valves, the ones made of treated bovine pericardium have become a frequently used replacement of the heart`s native valve. Lyophilization, also known as freeze-drying, is an extremely useful technique for tissue storage for surgical applications. This article gives a brief overview on the current bovine pericardium lyophilization development, including the chemical modification to improve physical-chemical characteristics and the advanced technologies used to guarantee a high-quality product. It was shown that lyophilization process can be successfully applied as a method of bovine pericardium preservation and also as a technological tool to prepare new materials obtained by chemical modification of native tissues

A new approach to heart valve tissue engineering:mimicking the heart ventricle with a ventricular assist device in a novel bioreactor.

The `biomimetic` approach to tissue engineering usually involves the use of a bioreactor mimicking physiological parameters whilst supplying nutrients to the developing tissue. Here we present a new heart valve bioreactor, having as its centrepiece a ventricular assist device (VAD), which exposes the cell-scaffold constructs to a wider array of mechanical forces. The pump of the VAD has two chambers: a blood and a pneumatic chamber, separated by an elastic membrane. Pulsatile air-pressure is generated by a piston-type actuator and delivered to the pneumatic chamber, ejecting the fluid in the blood chamber. Subsequently, applied vacuum to the pneumatic chamber causes the blood chamber to fill. A mechanical heart valve was placed in the VAD`s inflow position. The tissue engineered (TE) valve was placed in the outflow position. The VAD was coupled in series with a Windkessel compliance chamber, variable throttle and reservoir, connected by silicone tubings. The reservoir sat on an elevated platform, allowing adjustment of ventricular preload between 0 and 11 mmHg. To allow for sterile gaseous exchange between the circuit interior and exterior, a 0.2 mu m filter was placed at the reservoir. Pressure and flow were registered downstream of the TE valve. The circuit was filled with culture medium and fitted in a standard 5% CO(2) incubator set at 37 degrees C. Pressure and flow waveforms were similar to those obtained under physiological conditions for the pulmonary circulation. The `cardiomimetic` approach presented here represents a new perspective to conventional biomimetic approaches in TE, with potential advantages. Copyright (C) 2010 John Wiley & Sons, Ltd.Norwegian State Educational Loan FundSkipsreder Tom Wilhelmsens StiftelseKrista and Viggo Petersens FondKnut Hamsuns MinnefondHotelejer Anders Mansson og hustru Hanne Manssons LegatOticon FondenReinholdt W. Jorck og Hustrus FondNorwegian Society of Graduate Technical and Scientific Professional

Cavopulmonary anastomosis improves left ventricular assist device support in acute biventricular failure

Objective: Right ventricular failure during left ventricular assist device (WAD) support can result in severe hemodynamic compromise with high mortality. This study investigated the acute effects of cavopulmonary anastomosis on right ventricular loading and WAD performance in a model of severe biventricular failure. Methods: LVAD support was performed by means of centrifugal pump implantation in 14 anesthetized dogs (20-30 kg) with severe biventricular failure obtained by ventricular fibrillation induction. Animals were randomized to be submitted to classical cavopulmonary anastomosis (Glenn shunt) or to control group and were maintained under WAD support for 2 h. Left and right atrial, right ventricular and systemic pressures were monitored, white total pulmonary flow was simultaneously recorded by transonic flowmeters located on the superior vena cava and pulmonary trunk. Blood gas and venous lactate determinations were also obtained. Results: Ventricular fibrillation maintenance resulted in acute WAD performance impairment after 90 min in the control group, while animals with Glenn circuit maintained normal WAD pump flow (55 +/- 13 ml kg(-1) min(-1) vs 21 +/- 4 ml kg(-1) min(-1), p < 0.001) and better peripheral perfusion (blood lactate of 29 +/- 10 pg/ml vs 46 +/- 9 pg/ml, p < 0.001). Left and right atrial pressures did not change significantly, while right ventricular pressure was tower in animals with Glenn circuit (13 +/- 3 mmHg vs 22 +/- 8 mmHg, p = 0.005). Right ventricular unloading with Glenn shunt also resulted in superior total pulmonary flow (59 +/- 13 ml kg(-1) min(-1) vs 17 +/- 3 ml kg(-1) min(-1), p < 0.001). Conclusion: The concomitant use of cavopulmonary anastomosis during LVAD support in a model of severe biventricular failure limited right ventricular overloading and resulted in better hemodynamic performance. (C) 2008 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved