Incidência de distúrbios da condução atrioventricular e intraventricular após implante percutâneo da bioprótese valvar aórtica CoreValve / Incidence of atrioventricular and intraventricular conduction disorders after transcatheter aortic valve implantation with the CoreValve bioprosthesis

Introdução: O sistema de condução localizado no septo interventricular encontra-se anatomicamente contíguo ao anel valvar aórtico. Por isso, distúrbios na condução atrioventricular e intraventricular podem decorrer de inflamação, edema e estresse mecânico causados pelas hastes metálicas da bioprótese CoreValve. O objetivo deste estudo foi avaliar a incidência de distúrbios da condução atrioventricular e intraventricular após implante percutâneo da CoreValve. Método: Entre janeiro de 2008 e abril de 2010, 23 pacientes portadores de estenose aórtica foram submetidos a implante da CoreValve. A média de idade foi de 81 ± 8,3 anos, e 12 (52,1%) pacientes eram do sexo masculino. Resultados: Após o implante valvar, constataram-se as seguintes alterações na condução atrioventricular: 3 (13%) bloqueios atrioventriculares totais, 2 (8,7%) bloqueios atrioventriculares de 2º grau e 8 (34,8%) bloqueios atrioventriculares de 1º grau, sendo 4 (17,4%) novos e 4 preexistentes. Assim, distúrbios de condução mais avançados, como bloqueio atrioventricular de 2o grau e/ou bloqueio atrioventricular total ocorreram em 5 (21,7%) pacientes. Em relação aos distúrbios da condução intraventricular pós-implante, foram detectados 14 (60,9%) bloqueios completos de ramo esquerdo, sendo 2 (8,7%) com bloqueio completo de ramo direito e bloqueio completo de ramo esquerdo alternante. Nesta série, 7 (30,4%) pacientes foram submetidos a implante de marca-passo permanente, 6 (26,1%) deles por indicação absoluta. Todos os pacientes que apresentavam bloqueio completo de ramo direito antes do procedimento necessitaram do marca-passo permanente...

Background: There is a close anatomical relationship between the aortic valve annulus and the conduction system.Therefore, atrioventricular and intraventricular conduction disorders may occur as a result of inflammation, edema and mechanical stress caused by the metallic struts of the CoreValvebioprosthesis. The objective of this study was to evaluate the incidence of atrioventricular and intraventricular conduction disorders after percutaneous CoreValve implantation.Method: Between January 2008 and April 2010, 23 patients with aortic stenosis were submitted to CoreValve bioprosthesis implantation. Mean age was 81 ± 8.3 years and 12 (52.1%) patients were male. Results: After valve implantation, the following atrioventricular conduction disorderswere observed: 3 (13%) complete atrioventricular blocks, 2 (8.7%) 2nd degree atrioventricular blocks and 8 (34.8%) 1st degree atrioventricular blocks, of which 4 (17.4%) werenew and 4 were preexisting. Therefore, advanced conduction disorders, such as 2nd degree atrioventricular block and/orcomplete atrioventricular block were observed in 5 (21.7%) patients. As to post-implant intraventricular conductiondisorders, 14 (60.9%) left bundle branch blocks were observed, 2 (8.7%) of them with alternating right bundle branch block and left bundle branch block. In this series, 7 (30.4%) patients received a permanent pacemaker, 6 (26.1%) of them with absolute indication. All of the patients withright bundle branch block before the procedure required permanent pacemaker implantation. Conclusion: Atrioventricular conduction disorders and, specially, left bundle branch block are common after percutaneous implantation of the CoreValve prosthesis. Permanent pacemaker is required in approximately one fourth of the cases. The presence of pre-implant right bundle branch block is related to a greater risk of developing advanced conduction disorders.

Valve replacement in endocarditis: setting limits in noncompliant intravenous drug abusers.

An intravenous (IV) drug abuser underwent repeated valve replacements because of recurrent infective endocarditis. Is it ethically permissible to withhold valve surgery in a recalcitrant, noncompliant IV drug abuser? We believe so, and in our analysis, discuss the principles of futility, rationing, personal responsibility, and justice. Because of her continued drug abuse, the patient is responsible and accountable for the medical consequences. The consequences are that physicians will not be able to provide her with beneficial treatments without disproportionate harm, and that society will no longer be able to provide resources for her treatment without unfairly jeopardizing the availability of resources for other members of society. Although valve surgery does not constitute futile treatment, maximizing and egalitarian principles of societal justice support the withholding of such an expensive intervention. The patient should be jointly evaluated by the physician, social worker, and psychiatrist. The medical team will emphasize patient compliance and willingness to undergo drug rehabilitation, and will offer the first valve replacement. The recidivist abuser with demonstrable non-compliance who sustains a second episode of endocarditis need not be offered another valve. To avoid bedside rationing, we recommend the formulation of such a policy by nations and professional bodies.