A randomized clinical trial to evaluate the efficacy and safety of rivaroxaban in patients with bioprosthetic mitral valve and atrial fibrillation or flutter: rationale and design of the RIVER trial

Background The efficacy and safety of rivaroxaban in patients with bioprosthetic mitral valves and atrial fibrillation or flutter remain uncertain. Design RIVER was an academic-led, multicenter, open-label, randomized, non-inferiority trial with blinded outcome adjudication that enrolled 1005 patients from 49 sites in Brazil. Patients with a bioprosthetic mitral valve and atrial fibrillation or flutter were randomly assigned (1:1) to rivaroxaban 20 mg once daily (15 mg in those with creatinine clearance <50 mL/min) or dose-adjusted warfarin (target international normalized ratio 2.0-30.); the follow-up period was 12 months. The primary outcome was a composite of all-cause mortality, stroke, transient ischemic attack, major bleeding, valve thrombosis, systemic embolism, or hospitalization for heart failure. Secondary outcomes included individual components of the primary composite outcome, bleeding events, and venous thromboembolism. Summary RIVER represents the largest trial specifically designed to assess the efficacy and safety of a direct oral anticoagulant in patients with bioprosthetic mitral valves and atrial fibrillation or flutter. The results of this trial can inform clinical practice and international guidelines.

A randomized clinical trial to evaluate the efficacy and safety of rivaroxaban in patients with bioprosthetic mitral valve and atrial fibrillation or flutter: Rationale and design of the RIVER trial.

The efficacy and safety of rivaroxaban in patients with bioprosthetic mitral valves and atrial fibrillation or flutter remain uncertain. DESIGN: RIVER was an academic-led, multicenter, open-label, randomized, non-inferiority trial with blinded outcome adjudication that enrolled 1005 patients from 49 sites in Brazil. Patients with a bioprosthetic mitral valve and atrial fibrillation or flutter were randomly assigned (1:1) to rivaroxaban 20 mg once daily (15 mg in those with creatinine clearance <50 mL/min) or dose-adjusted warfarin (target international normalized ratio 2.0-30.); the follow-up period was 12 months. The primary outcome was a composite of all-cause mortality, stroke, transient ischemic attack, major bleeding, valve thrombosis, systemic embolism, or hospitalization for heart failure. Secondary outcomes included individual components of the primary composite outcome, bleeding events, and venous thromboembolism. SUMMARY: RIVER represents the largest trial specifically designed to assess the efficacy and safety of a direct oral anticoagulant in patients with bioprosthetic mitral valves and atrial fibrillation or flutter. The results of this trial can inform clinical practice and international guidelines.

Rivaroxaban in Patients with Atrial Fibrillation and a Bioprosthetic Mitral Valve.

BACKGROUND: The effects of rivaroxaban in patients with atrial fibrillation and a bioprosthetic mitral valve remain uncertain. METHODS: In this randomized trial, we compared rivaroxaban (20 mg once daily) with dose-adjusted warfarin (target international normalized ratio, 2.0 to 3.0) in patients with atrial fibrillation and a bioprosthetic mitral valve. The primary outcome was a composite of death, major cardiovascular events (stroke, transient ischemic attack, systemic embolism, valve thrombosis, or hospitalization for heart failure), or major bleeding at 12 months. RESULTS: A total of 1005 patients were enrolled at 49 sites in Brazil. A primary-outcome event occurred at a mean of 347.5 days in the rivaroxaban group and 340.1 days in the warfarin group (difference calculated as restricted mean survival time, 7.4 days; 95% confidence interval [CI], -1.4 to 16.3; P<0.001 for noninferiority). Death from cardiovascular causes or thromboembolic events occurred in 17 patients (3.4%) in the rivaroxaban group and in 26 (5.1%) in the warfarin group (hazard ratio, 0.65; 95% CI, 0.35 to 1.20). The incidence of stroke was 0.6% in the rivaroxaban group and 2.4% in the warfarin group (hazard ratio, 0.25; 95% CI, 0.07 to 0.88). Major bleeding occurred in 7 patients (1.4%) in the rivaroxaban group and in 13 (2.6%) in the warfarin group (hazard ratio, 0.54; 95% CI, 0.21 to 1.35). The frequency of other serious adverse events was similar in the two groups. CONCLUSIONS: In patients with atrial fibrillation and a bioprosthetic mitral valve, rivaroxaban was noninferior to warfarin with respect to the mean time until the primary outcome of death, major cardiovascular events, or major bleeding at 12 months. (Funded by PROADI-SUS and Bayer; RIVER ClinicalTrials.gov number, NCT02303795.).

Rivaroxaban in patients with atrial fibrillation and a bioprosthetic mitral valve

BACKGROUND The effects of rivaroxaban in patients with atrial fibrillation and a bioprosthetic mitral valve remain uncertain. METHODS In this randomized trial, we compared rivaroxaban (20 mg once daily) with dose adjusted warfarin (target international normalized ratio, 2.0 to 3.0) in patients with atrial fibrillation and a bioprosthetic mitral valve. The primary outcome was a composite of death, major cardiovascular events (stroke, transient ischemic attack, systemic embolism, valve thrombosis, or hospitalization for heart failure), or major bleeding at 12 months. RESULTS A total of 1005 patients were enrolled at 49 sites in Brazil. A primary-outcome event occurred at a mean of 347.5 days in the rivaroxaban group and 340.1 days in the warfarin group (difference calculated as restricted mean survival time, 7.4 days; 95% confidence interval [CI], −1.4 to 16.3; P<0.001 for noninferiority). Death from cardiovascular causes or thromboembolic events occurred in 17 patients (3.4%) in the rivaroxaban group and in 26 (5.1%) in the warfarin group (hazard ratio, 0.65; 95% CI, 0.35 to 1.20). The incidence of stroke was 0.6% in the rivaroxaban group and 2.4% in the warfarin group (hazard ratio, 0.25; 95% CI, 0.07 to 0.88). Major bleeding occurred in 7 patients (1.4%) in the rivaroxaban group and in 13 (2.6%) in the warfarin group (hazard ratio, 0.54; 95% CI, 0.21 to 1.35). The frequency of other serious adverse events was similar in the two groups. CONCLUSIONS In patients with atrial fibrillation and a bioprosthetic mitral valve, rivaroxaban was noninferior to warfarin with respect to the mean time until the primary outcome of death, major cardiovascular events, or major bleeding at 12 months.

Terapia anticoagulante no tromboembolismo venoso / Anticoagulant therapy in venous thromboembolism

Introdução: O tromboembolismo venoso (TEV), incluindo a embolia pulmonar (EP) e a trombose venosa profunda (TVP), é a terceira causa de mortalidade em todo o mundo. O diagnóstico ainda é subestimado nas emergências. Os fatores desencadeantes são bem definidos, o que auxilia a estratificação de risco e o diagnóstico de TEV provocada ou não e influenciará muito o tempo de tratamento. O aumento do ventrículo direito e de marcadores biológicos tem desempenhado grande papel no prognóstico. O quadro clínico é bem definido e tem várias ferramentas, tanto para o diagnóstico como para a estratificação de risco, tais como os critérios de Wells e de Genebra, além de outros. Os exames complementares atualmente estão bem definidos, com a angiografia pulmonar sendo o padrão de referência; porém, com a melhora da tecnologia e a alta sensibilidade e especificidade, a angiotomografia computadorizada ocupou um lugar de destaque. Outros exames ainda são importantes em várias situações, como o D-dímero e outros biomarcadores, a radiografia de tórax, a cintilografia de perfusão/ventilação, eletrocardiograma, ecocardiografia e doppler venoso de membros inferiores. Método: Neste artigo, revisamos aspectos básicos de epidemiologia, diagnóstico e estratificação de risco. O foco principal foi o tratamento com a terapia anticoagulante, sobre a qual revisamos os seis estudos clínicos descritos entre 2009 e 2013, que abordam os novos anticoagulantes orais, hoje denominados anticoagulantes orais diretos. Esses estudos têm desenhos diferentes, com três deles começando com anticoagulantes orais desde o início do quadro agudo de TVP e EP (rivaroxabana e edoxabana). Os outros três iniciaram com enoxaparina e varfarina durante os primeiros dias e depois seguiram com a medicação do grupo em avaliação (dabigatrana e apixabana). Resultados: Nos estudos analisados, todos obtiveram uma redução (valor de p de não inferioridade) dos eventos de recorrência de TEV com relação à varfarina. Nos desfechos de segurança, definidos como sangramento fatal, clinicamente relevante e outros, os novos anticoagulantes orais obtiveram uma diminuição significativa. Conclusões: Os anticoagulantes orais diretos tiveram redução da recorrência de eventos tromboembólicos (periférico e pulmonar), com redução significativa dos índices de sangramentos fatais ou não. A segurança coloca-os como opção segura e eficaz para o tratamento desses pacientes com risco baixo e intermediário de TEV

Introduction: Venous thromboembolism (VTE), including pulmonary embolism (PE) and deep vein thrombosis (DVT), is the third leading cause of death worldwide. The diagnosis is still underestimated in emergencies. The triggering factors are well defined, which assists in the stratification of risk and in the diagnosis of VTE, whether provoked or not, and will greatly influence the treatment time. Increased right ventricle and biological markers have played a large role in the prognosis. The clinical features are well defined, and there are various tools for diagnosis and for risk stratification, such as the Wells and Geneva criteria, among others. Complementary exams are now well defined, with pulmonary angiography being the gold standard, but with improved technology and high sensitivity and specificity, computerized angiotomography has played a prominent role. Other exams are still important in certain situations, such as D-dimer and other biomarkers, chest radiography, perfusion/ventilation scintigraphy, electrocardiogram, echocardiography, and lower limb venous Doppler. Method: In this article we review basic aspects of epidemiology, diagnosis, and risk stratification. The main focus was treatment with anticoagulant therapy, under which we reviewed the six clinical studies described between 2009 and 2013 that address the new oral anticoagulants, now called direct oral anticoagulants. These studies have different designs; three of them start with oral anticoagulants from the onset of acute DVT and PE (rivaroxaban and edoxaban), and the other three start with enoxaparin and warfarin during the first days and then with the medication of the study group being evaluated (dabigatran and apixaban). Results: In the analyzed studies, all of them obtained a reduction (non-inferiority p-value) of the events of VTE recurrence in relation to warfarin. In the safety outcomes, defined as clinically relevant fatal bleeding and others, the new oral anticoagulants achieved a significant reduction. Conclusions: Direct oral anticoagulants had a reduction in the recurrence of thromboembolic events (peripheral and pulmonary), with a significant reduction in rates of fatal or non-fatal bleeding. Their safety makes them a reliable and effective option for the treatment of these patients, with low and intermediate risk of VTE

Videodensitometric analysis of advanced carotid plaque: correlation with MMP-9 and TIMP-1 expression.

BACKGROUND: Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of MMP (TIMP) promote derangement of the extracellular matrix, which is ultimately reflected in plaque images seen on ultrasound. Videodensitometry can identify structural disturbances in plaques. OBJECTIVES: To establish the correlations between values determined using videodensitometry in B-mode ultrasound images of advanced carotid plaques and the total expression of MMP-9 and TIMP-1 in these removed plaques. METHODS: Thirty patients underwent ultrasonic tissue characterization of carotid plaques before surgery, using mean gray level (MGL), energy, entropy and homogeneity. Each patient was assigned preoperatively to one of 2 groups: group I, symptomatic patients (n = 16; 12 males; mean age 66.7 ± 6.8 years), and group II, asymptomatic patients (n = 14; 8 males; mean age 67.6 ± 6.81 years). Tissue specimens were analyzed for MMP-9 and TIMP-1 expression. Nine carotid arteries were used as normal tissue controls. RESULTS: MMP-9 expression levels were elevated in group II and in normal tissues compared to group I (p < 0.001). TIMP-1 levels were higher in group II than in group I, and significantly higher in normal tissues than in group I (p = 0.039). The MGL was higher in group II compared to group I (p = 0.038). Energy had greater values in group II compared to group I (p = 0.02). There were no differences between patient groups in homogeneity and entropy. Energy positively correlated with MMP-9 and TIMP-1 expression (p = 0.012 and p = 0.031 respectively). Homogeneity positively correlated with MMP-9 and TIMP-1 expression (p = 0.034 and p = 0.047 respectively). There were no correlations between protein expression and MGL or entropy. CONCLUSIONS: Videodensitometric computer analysis of ultrasound scanning images can be used to identify stable carotid plaques, which have higher total expression levels of MMP-9 and TIMP-1 than unstable plaques.

Assessment of MMP-9, TIMP-1, and COX-2 in normal tissue and in advanced symptomatic and asymptomatic carotid plaques.

BACKGROUND: Mature carotid plaques are complex structures, and their histological classification is challenging. The carotid plaques of asymptomatic and symptomatic patients could exhibit identical histological components. OBJECTIVES: To investigate whether matrix metalloproteinase 9 (MMP-9), tissue inhibitor of MMP (TIMP), and cyclooxygenase-2 (COX-2) have different expression levels in advanced symptomatic carotid plaques, asymptomatic carotid plaques, and normal tissue. METHODS: Thirty patients admitted for carotid endarterectomy were selected. Each patient was assigned preoperatively to one of two groups: group I consisted of symptomatic patients (n = 16, 12 males, mean age 66.7 ± 6.8 years), and group II consisted of asymptomatic patients (n = 14, 8 males, mean age 67.6 ± 6.81 years). Nine normal carotid arteries were used as control. Tissue specimens were analyzed for fibromuscular, lipid and calcium contents. The expressions of MMP-9, TIMP-1 and COX-2 in each plaque were quantified. RESULTS: Fifty-eight percent of all carotid plaques were classified as Type VI according to the American Heart Association Committee on Vascular Lesions. The control carotid arteries all were classified as Type III. The median percentage of fibromuscular tissue was significantly greater in group II compared to group I (p < 0.05). The median percentage of lipid tissue had a tendency to be greater in group I than in group II (p = 0.057). The percentages of calcification were similar among the two groups. MMP-9 protein expression levels were significantly higher in group II and in the control group when compared with group I (p < 0.001). TIMP-1 expression levels were significantly higher in the control group and in group II when compared to group I, with statistical difference between control group and group I (p = 0.010). COX-2 expression levels did not differ among groups. There was no statistical correlation between MMP-9, COX-2, and TIMP-1 levels and fibrous tissue. CONCLUSIONS: MMP-9 and TIMP-1 are present in all stages of atherosclerotic plaque progression, from normal tissue to advanced lesions. When sections of a plaque are analyzed without preselection, MMP-9 concentration is higher in normal tissues and asymptomatic surgical specimens than in symptomatic specimens, and TIMP-1 concentration is higher in normal tissue than in symptomatic specimens.

The effect of L-arginine on neointimal proliferation and artery remodeling on an iliac artery lesion caused by a balloon catheter in hypercholesterolemic rabbits.

OBJECTIVE: It has been implied that neointimal proliferation and remodeling are the major causes of restenosis. The objective of this study is to assess the effect of orally administered L-arginine on these two factors in hypercholesterolemic rabbits that had suffered an injury to their iliac arteries caused by a catheter balloon. METHODS: The study included nineteen rabbits that were divided in two groups: control (CG) and arginine (AG). There were 19 arteries studied from the control group and 17 in the arginine group. The animals were placed on a 2% hypercholesterolemic diet for 15 days and then submitted to a balloon angioplasty in order to produce a lesion in their iliac arteries. Next, the AG animals were given a 1g/kg/day oral dose of a L-arginine solution. The animals were sacrificed 15 days after the angioplasty procedure and histological artery sections were prepared, stained and fixed. The ratio between the neointimal area (in mm(2)) and the media layer (in mm(2)) was used to represent lesion development. In order to determine remodeling, the ratio between the total area of the medial portion of the vessel (greater balloon contact) and the total area of the reference segment of the vessel (less balloon contact) was used. RESULTS: Mean neointimal thickness (NI/M) was 0.8151+/-0.2201 in CG and 0.3296+/-0.1133 in AG. Remodeling patterns for the two groups studied were similar. CONCLUSION: In the experimental model used, L-arginine was able to reduce intimal tissue thickness in hypercholesterolemic rabbits but did not act on artery remodeling.

Efeito da L-arginina na neoproliferação intimal e no remodelamento arterial após lesão por balão, em ilíacas de coelhos hipercolesterolêmicos / The effect of L-arginine on neointimal proliferation and artery remodeling on an iliac artery lesion caused by a balloon catheter in hypercholesterolemic rabbits / The effect of L-arginine on neointimal proliferation and artery remodeling on an iliac artery lesion caused by a balloon catheter in hypercholesterolemic rabbits

OBJETIVO: A neoproliferação intimal e o remodelamento têm sido implicados como os maiores fatores causadores de reestenose. O objetivo deste trabalho é estudar a ação da L-arginina por via oral, nesses dois fatores, após lesão por balão, em artérias ilíacas de coelhos hipercolesterolêmicos. MÉTODOS: Foram utilizados dezenove coelhos, que foram divididos em dois grupos: controle (GC) e arginina (GA), respectivamente com dezenove e dezessete artérias estudadas. Os animais foram submetidos a lesão por balão de angioplastia, em suas artérias ilíacas, quinze dias após início de dieta hipercolesterolêmica a 2 por cento. A seguir, os animais do GA passaram a receber uma solução de L-arginina, por via oral, na dose de 1 g/kg/dia. Após o sacrifício, no 15° dia após a lesão por balão, procedeu-se a cortes histológicos das artérias, as quais foram coradas e fixadas. Utilizou-se como representativa do desenvolvimento da lesão a razão da área da neoíntima (em mm²) pela camada média (em mm²). Por sua vez, a razão da área total do vaso em sua porção medial (de maior contato com o balão) pela área total do vaso no segmento referencial (de menor contato com o balão) foi a definidora do remodelamento. RESULTADOS: A média do espessamento neointimal (NI/M) foi de 0,8151±0,2201 no GC e de 0,3296±0,1133 no GA. Não houve diferença entre os tipos de remodelamento entre os dois grupos estudados. CONCLUSÃO: No modelo experimental utilizado, a L-arginina foi capaz de reduzir o espessamento intimal em coelhos hipercolesterolêmicos e não teve ação sobre o remodelamento arterial.

OBJECTIVE: It has been implied that neointimal proliferation and remodeling are the major causes of restenosis. The objective of this study is to assess the effect of orally administered L-arginine on these two factors in hypercholesterolemic rabbits that had suffered an injury to their iliac arteries caused by a catheter balloon. METHODS: The study included nineteen rabbits that were divided in two groups: control (CG) and arginine (AG). There were 19 arteries studied from the control group and 17 in the arginine group. The animals were placed on a 2 percent hypercholesterolemic diet for 15 days and then submitted to a balloon angioplasty in order to produce a lesion in their iliac arteries. Next, the AG animals were given a 1g/kg/day oral dose of a L-arginine solution. The animals were sacrificed 15 days after the angioplasty procedure and histological artery sections were prepared, stained and fixed. The ratio between the neointimal area (in mm²) and the media layer (in mm²) was used to represent lesion development. In order to determine remodeling, the ratio between the total area of the medial portion of the vessel (greater balloon contact) and the total area of the reference segment of the vessel (less balloon contact) was used. RESULTS: Mean neointimal thickness (NI/M) was 0.8151±0.2201 in CG and 0.3296±0.1133 in AG. Remodeling patterns for the two groups studied were similar. CONCLUSION: In the experimental model used, L-arginine was able to reduce intimal tissue thickness in hypercholesterolemic rabbits but did not act on artery remodeling.

Obstruction of the left ventricular outflow tract after mitral valvuloplasty with implantation of Gregori's ring.

Mitral valvuloplasty is efficient for repairing mitral valve disease with few complications. In some cases, obstruction of the left ventricular outflow tract may occur due to systolic anterior motion of the mitral valve. We report the case of a patient with this complication and a pressure gradient between the left ventricle and the aorta of 130 mm Hg after mitral valvuloplasty with implantation of a Gregori's ring. The management was clinical with suspension of the vasoactive drugs and introduction of a beta-blocker. Two years after the surgery, the patient is asymptomatic and has a normal life.

Obstruçäo da via de saída do ventrículo esquerdo após plastia valvar mitral com implante do anel de Gregori / Obstruction of the left ventricular outflow tract after mitral valvuloplasty with implantation of Gregori's ring

Mitral valvuloplasty is efficient for repairing mitral valve disease with few complications. In some cases, obstruction of the left ventricular outflow tract may occur due to systolic anterior motion of the mitral valve. We report the case of a patient with this complication and a pressure gradient between the left ventricle and the aorta of 130 mm Hg after mitral valvuloplasty with implantation of a Gregori's ring. The management was clinical with suspension of the vasoactive drugs and introduction of a beta-blocker. Two years after the surgery, the patient is asymptomatic and has a normal life