Ring Fracture of Brazilian Aortic Valve Bioprostheses Using Non-Compliant High-Pressure Transcatheter Balloon, an Ex Vivo Test

ABSTRACT Introduction: Aortic valve bioprostheses ring fracture in valve-in-valve procedures has shown low complication rates and presents as an option in the treatment of patients at high risk for conventional surgery, avoiding high transvalvular gradients, which are associated with increased mortality. Some prostheses available in the market cannot be fractured. In an ex vivo test, the possibility of ring fracture of aortic valve bioprostheses produced in Brazil when submitted to radial force application using a high-pressure non-compliant balloon was evaluated. Methods: One unit of each aortic valve bioprosthesis model, sizes 19 and 21 mm, produced by Brazilian companies (Braile Biomédica, Cardioprótese, and Labcor), was used. In the experiment, a non-compliant high-pressure balloon (Atlas®-Gold), 1 mm larger than the external diameter of the prosthesis, was positioned inside the valve annulus and inflated gradually aiming to fracture the prosthesis. Fracture pressures and photographic and radiological images of the prostheses before and after test were recorded. Results: All prostheses were fractured. In the models with metal ring, the fracture pressures were between 23 and 25 atm. In the other prostheses, the rupture occurred between 10 and 13 atm. No deformations in the structure were observed, which could potentially damage the aortic root. Conclusion: All the Brazilian prostheses evaluated were fractured, although the presence of a metal ring in the prosthesis framework increases the pressure required for fracture. The information obtained helps in the planning of valve-in-valve procedures in patients with aortic valve bioprostheses.

Cardiovascular Surgery Residency Program: Training Coronary Anastomosis Using the Arroyo Simulator and UNIFESP Models

ABSTRACT OBJECTIVE: Engage the UNIFESP Cardiovascular Surgery residents in coronary anastomosis, assess their skills and certify results, using the Arroyo Anastomosis Simulator and UNIFESP surgical models. METHODS: First to 6th year residents attended a weekly program of technical training in coronary anastomosis, using 4 simulation models: 1. Arroyo simulator; 2. Dummy with a plastic heart; 3. Dummy with a bovine heart; and 4. Dummy with a beating pig heart. The assessment test was comprised of 10 items, using a scale from 1 to 5 points in each of them, creating a global score of 50 points maximum. RESULTS: The technical performance of the candidate showed improvement in all items, especially manual skill and technical progress, critical sense of the work performed, confidence in the procedure and reduction of the time needed to perform the anastomosis after 12 weeks practice. In response to the multiplicity of factors that currently influence the cardiovascular surgeon training, there have been combined efforts to reform the practices of surgical medical training. CONCLUSION: 1 - The four models of simulators offer a considerable contribution to the field of cardiovascular surgery, improving the skill and dexterity of the surgeon in training. 2 - Residents have shown interest in training and cooperate in the development of innovative procedures for surgical medical training in the art.

Absence of arteriosclerosis in intramyocardial coronary arteries: a mystery to be solved? / Ausência de arteriosclerose na porção intramiocárdica das artérias coronárias: um mistério a ser resolvido?

Several studies show that portions of intramyocardial coronary arteries are spared of arteriosclerosis, involving morphological, embryological, biochemical and pathophysiological aspects. Endothelial function is significantly affected in the segment of transition, as estimated by the vasoactive response to Ach. These findings suggest that myocardial bridge can provide protection against arteriosclerosis by counteracting the negative effects of endothelial dysfunction. The intramyocardial portion's protection phenomenon deserves further scientific research on all research fronts. Improved morphological, biomechanical and especially physiological and embryological knowledge may be the key to a future window of opportunity for chronic arterial disease therapy and prevention. In addition, this review discusses possible therapeutic approaches for symptomatic coronary ischemia caused by myocardial bridges.

Diversos estudos demonstram que as porções intramiocárdicas das artérias coronárias são poupadas da arteriosclerose, envolvendo aspectos morfológicos, embriológicos, biomecânicos e aspectos fisiopatológicos. A função endotelial é significativamente afetada no segmento de transição, tal como estimado pela resposta vasoativa para acetilcolina (Ach). Esses achados sugerem que ponte miocárdica pode fornecer proteção contra a arteriosclerose, por contrariar os efeitos negativos da disfunção endotelial. O fenômeno dessa proteção da porção intramiocárdica merece maior investigação científica em todas as frentes de pesquisa. Maiores conhecimentos sobre os aspectos morfológicos, biomecânicos e, principalmente, fisiológicos e embriológicos podem ser a chave para uma futura janela de oportunidades de terapia e prevenção da doença arterial crônica. Nessa revisão, discutem-se, também, possíveis abordagens terapêuticas para fenômenos coronarianos isquêmicos causados por pontes miocárdicas.

Circulação extracorpórea em adultos no século XXI: ciência, arte ou empirismo?: [revisão] / Adult cardiopulmonary bypass in the twentieth century: science, art or empiricism?: [review]

A presente revisão tem por objetivo ressaltar alguns aspectos pouco discutidos da circulação extracorpórea (CEC), levando-se em consideração fisiologia, fisiopatologia e algumas novas tecnologias de perfusão. Assim, alguns aspectos, até certo ponto filosóficos, motivaram a elaboração dessa revisão: a) Preservar e atualizar os conhecimentos do cirurgião sobre a CEC, pelo simples fato de manter a sua liderança pedagógica sobre a sua equipe; b) Questionar se pacientes idosos e diabéticos pelas suas características individuais, assim como adotado para crianças, talvez merecessem protocolos mais apropriados; c) Questionar a reação inflamatória sistêmica causada pela exposição do sangue à superfície não endotelizada do circuito de CEC diante da importância crescente do contato do sangue com a ferida cirúrgica; d) Em relação ao tratamento da síndrome vasoplégica, o azul de metileno continua sendo a melhor opção terapêutica, embora, muitas vezes não seja eficiente pela existência de uma "janela terapêutica" embasada na dinâmica da ação da guanilato ciclase (saturação e síntese "de novo") e; finalmente, e) Razão da escolha do título, ressaltando que, em seus moldes atuais, a CEC seria conseqüência do empirismo, arte, ou da ciência? A mensagem final vem com a convicção de que tanto o empirismo, a arte e a ciência são muito fortes em se tratando da CEC.

The aim of the present review is to highlight some less discussed aspects of the cardiopulmonary bypass (CPB), taking into consideration the physiology, physiopathology, and some new technologies of perfusion. Thus, some points, to a certain extent philosophical, have motivated this revision: a) To preserve and update the surgeon knowledge regarding CPB, even to keep his/her pedagogical leadership on his/her surgical team; b) To question if elderly and diabetic patients, as a result of their individual characteristics deserve more appropriate protocols similar to those adopted for children; c) One third aspect would be the questioning of the systemic inflammatory reaction caused by the blood exposure to CPB non-endothelized circuit surface, in face of the increasing importance of blood contact with the surgical wound; d) In relation to the treatment of the vasoplegic syndrome, methylene blue continues being the best therapeutical option, even so, many times are not efficient on account of a highly probable existence of a "therapeutical window" based on the guanylate cyclase dynamics of action (saturation and synthesis "de novo") and; finally, e) The reason of the title, highlighting that based on its current patterns, would the CPB be an outcome of empiricism, art, or science? The bottom line of this article carries the certainty of that as much as the empiricism, art, and science are highly related to CPB.