RESUMO
The objective of this study was to evaluate the effect of chemical treatment with glutamic acid to avoid calcification of biological cardiac valves. The bovine pericardium (BP) tissues were fixed with 0.5% glutaraldehyde (BP/GA), followed by treatment with glutamic acid (BP/GA + Glu) for neutralization of the free aldehyde groups. Microscopic analysis showed that the wavy structure of collagen fibrils was preserved, but changes in elastin's integrity occurred. However, the treatment did not promote undesirable changes in the thermal and mechanical properties of the modified BPs. These samples were systematically studied in rat subcutaneous tissue: control (BP/GA) and anticalcificant (BP/GA + Glu). After 60 days, both groups induced similar inflammatory reactions. In terms of calcification, BP/GA + Glu remained more stable with a lower index (3.1 ± 0.2 µg Ca2+ /mg dry tissue), whereas for BP/GA it was 5.7 ± 1.3 µg Ca2+ /mg dry tissue. Bioprostheses made from BP/GA + Glu were implanted in the pulmonary position in sheep, and in vivo echocardiographic analyses revealed maintenance of valvar function after 180 days, with low gradients and minimal valve insufficiency. The explanted tissues of the BP/GA + Glu group had a lower average calcium content 3.8 ± 3.0 µg Ca2+ /mg dry tissue. The results indicated high anticalcification efficiency of BP/GA + Glu in both subcutaneous implant in rats and in the experimental sheep model, which is an advantage that should encourage the industrial application of these materials for the manufacture of bioprostheses.
Assuntos
Bioprótese , Calcificação Fisiológica/efeitos dos fármacos , Bovinos , Ácido Glutâmico/farmacologia , Próteses Valvulares Cardíacas , Animais , Bovinos/fisiologia , Glutaral/farmacologia , Valvas Cardíacas/efeitos dos fármacos , Valvas Cardíacas/fisiologia , Pericárdio/efeitos dos fármacos , Pericárdio/fisiologiaRESUMO
INTRODUCTION: Mechanical heart valves (MHV) are extremely durable, but they require permanent use of anticoagulation to prevent thromboembolic events. The only approved therapeutic options are vitamin K antagonists (VKAs), such as warfarin. As a drug class, clinical management is difficult, therefore new alternatives need to be evaluated. METHODS: RIWA is a phase II/III, prospective, open-label, randomized, pilot study designed to investigate oral rivaroxaban 15 mg twice daily compared with dose-adjusted warfarin for the prevention of stroke (ischemic or hemorrhagic) and systemic embolism in patients with MHV, from August 2018 to December 2019. Patients will undergo transesophageal echocardiography at the beginning and the end of the study (follow-up time 90 days). On an explanatory basis, all events will be analyzed, including stroke, peripheral systemic embolism, valve thrombosis, significant bleeding and death. DISCUSSION: Warfarin and similar VKAs are standard therapy for patients with an MHV. Even with the appropriate use of therapy, the incidence of thromboembolic events is high at 1-4% per year. Furthermore, bleeding risk is significant, ranging from 2 to 9% per year. The new frontier to be overcome in relation to use of the new oral anticoagulants is undoubtedly in patients with MHV. A significant portion of people with MHV worldwide will benefit if noninferiority of these new agents is confirmed. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03566303. Recruitment Status: Recruiting. First Posted: 25 June 2018. Last Update Posted: 25 June 2018.
Assuntos
Anticoagulantes/farmacologia , Doenças das Valvas Cardíacas/tratamento farmacológico , Valvas Cardíacas/efeitos dos fármacos , Rivaroxabana/farmacologia , Varfarina/farmacologia , Adolescente , Adulto , Idoso , Anticoagulantes/administração & dosagem , Procedimentos Cirúrgicos Cardíacos , Ensaios Clínicos Fase I como Assunto , Ensaios Clínicos Fase II como Assunto , Ecocardiografia Transesofagiana , Humanos , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Ensaios Clínicos Controlados Aleatórios como Assunto , Rivaroxabana/administração & dosagem , Varfarina/administração & dosagem , Adulto JovemRESUMO
BACKGROUND AND AIM OF THE STUDY: Aprotinin is effective in promoting hemostasis, notably in cardiac surgery with cardiopulmonary bypass. Its efficacy has been shown in coronary bypass graft operations. However, few reports exist of aprotinin use in valve operations, and in those studies only the full dose was used. Thus, our aim was to evaluate the effects of low-dose aprotinin in patients undergoing heart valve reoperation. METHODS: Eighteen patients having reoperative valve surgery received 10(6) KIU aprotinin after induction of anesthesia, and a further 10(6) KIU in the pump prime. A group of 18 similar patients who were operated on but did not receive aprotinin were used as controls. RESULTS: A significant reduction in postoperative blood loss (approximately 470 ml) occurred in patients receiving aprotinin. These patients also presented less postoperative bleeding than untreated patients in 70.4% of cases. No adverse effects of the drug were noted, except for one case of allergic reaction. CONCLUSION: The systematic use of low-dose aprotinin should be considered in valve reoperation, except in cases of re-exposure to the drug, or allergic reaction.