Rosuvastatin prevents myocardial necrosis in an experimental model of acute myocardial infarction

Dyslipidemia is related to the progression of atherosclerosis and is an important risk factor for acute coronary syndromes. Our objective was to determine the effect of rosuvastatin on myocardial necrosis in an experimental model of acute myocardial infarction (AMI). Male Wistar rats (8-10 weeks old, 250-350 g) were subjected to definitive occlusion of the left anterior descending coronary artery to cause AMI. Animals were divided into 6 groups of 8 to 11 rats per group: G1, normocholesterolemic diet; G2, normocholesterolemic diet and rosuvastatin (1 mg·kg(-1)·day-1) 30 days after AMI; G3, normocholesterolemic diet and rosuvastatin (1 mg·kg(-1)·day-1) 30 days before and after AMI; G4, hypercholesterolemic diet; G5, hypercholesterolemic diet and rosuvastatin (1 mg·kg(-1)·day-1) 30 days after AMI; G6, hypercholesterolemic diet and rosuvastatin (1 mg·kg(-1)·day-1) 30 days before and after AMI. Left ventricular function was determined by echocardiography and percent infarct area by histology. Fractional shortening of the left ventricle was normal at baseline and decreased significantly after AMI (P < 0.05 in all groups), being lower in G4 and G5 than in the other groups. No significant difference in fractional shortening was observed between G6 and the groups on the normocholesterolemic diet. Percent infarct area was significantly higher in G4 than in G3. No significant differences were observed in infarct area among the other groups. We conclude that a hypercholesterolemic diet resulted in reduced cardiac function after AMI, which was reversed with rosuvastatin when started 30 days before AMI. A normocholesterolemic diet associated with rosuvastatin before and after AMI prevented myocardial necrosis when compared with the hypercholesterolemic condition.

Rosuvastatin prevents myocardial necrosis in an experimental model of acute myocardial infarction

Dyslipidemia is related to the progression of atherosclerosis and is an important risk factor for acute coronary syndromes. Our objective was to determine the effect of rosuvastatin on myocardial necrosis in an experimental model of acute myocardial infarction (AMI). Male Wistar rats (8-10 weeks old, 250-350 g) were subjected to definitive occlusion of the left anterior descending coronary artery to cause AMI. Animals were divided into 6 groups of 8 to 11 rats per group: G1, normocholesterolemic diet; G2, normocholesterolemic diet and rosuvastatin (1 mg·kg(-1)·day-1) 30 days after AMI; G3, normocholesterolemic diet and rosuvastatin (1 mg·kg(-1)·day-1) 30 days before and after AMI; G4, hypercholesterolemic diet; G5, hypercholesterolemic diet and rosuvastatin (1 mg·kg(-1)·day-1) 30 days after AMI; G6, hypercholesterolemic diet and rosuvastatin (1 mg·kg(-1)·day-1) 30 days before and after AMI. Left ventricular function was determined by echocardiography and percent infarct area by histology. Fractional shortening of the left ventricle was normal at baseline and decreased significantly after AMI (P < 0.05 in all groups), being lower in G4 and G5 than in the other groups. No significant difference in fractional shortening was observed between G6 and the groups on the normocholesterolemic diet. Percent infarct area was significantly higher in G4 than in G3. No significant differences were observed in infarct area among the other groups. We conclude that a hypercholesterolemic diet resulted in reduced cardiac function after AMI, which was reversed with rosuvastatin when started 30 days before AMI. A normocholesterolemic diet associated with rosuvastatin before and after AMI prevented myocardial necrosis when compared with the hypercholesterolemic condition.

Report From The International Society for Nomenclature of Paediatric and Congenital Heart Disease

Tremendous progress has been made in the field of pediatric heart disease over the past 30 years. Although survival after heart surgery in children has improved dramatically, complications still occur, and optimization of outcomes for all patients remains a challenge. To improve outcomes, collaborative efforts are required and ultimately depend on the possibility of using a common language when discussing pediatric and congenital heart disease. Such a universal language has been developed and named the International Pediatric and Congenital Cardiac Code (IPCCC). To make the IPCCC more universally understood, efforts are under way to link the IPCCC to pictures and videos. The Archiving Working Group is an organization composed of leaders within the international pediatric cardiac medical community and part of the International Society for Nomenclature of Paediatric and Congenital Heart Disease ( www.ipccc.net ). Its purpose is to illustrate, with representative images of all types and formats, the pertinent aspects of cardiac diseases that affect neonates, infants, children, and adults with congenital heart disease, using the codes and definitions associated with the IPCCC as the organizational backbone. The Archiving Working Group certifies and links images and videos to the appropriate term and definition in the IPCCC. These images and videos are then displayed in an electronic format on the Internet. The purpose of this publication is to report the recent progress made by the Archiving Working Group in establishing an Internet-based, image encyclopedia that is based on the standards of the IPCCC.

Avaliação eletrocardiográfica em cães submetidos à pneumonectomia direita

O propósito das ressecções pulmonares em cães e gatos, quer sejam por lobectomia ou pneumonectomia, é a cura ou paliação de processos broncopulmonares sempre que os meios conservadores de tratamento clínico sejam considerados ineficientes. Tendo em vista as significativas alterações resultantes da pneumonectomia, novos estudos experimentais devem ser feitos para avaliar as vantagens dessa intervenção cirúrgica e determinar a maneira como aplicá-la com segurança. O presente estudo tem como objetivo avaliar as alterações eletrocardiográficas em dez cães adultos de ambos os sexos, sem raça definida, com 10-30 kg, submetidos à pneumonectomia direita. Foram avaliados diariamente os parâmetros clínicos de cada cão e as alterações em todas as derivações do eletrocardiograma. Todos os cães apresentaram um bom desenlace pós-operatório. Apenas um cão apresentou alteração de relevância clínica, um caso de complexos ventriculares prematuros, possivelmente decorrente da parada cardiorrespiratória, que foi revertido com sucesso. Houve diminuição da amplitude dos complexos QRS nos primeiros 14 dias, retornado ao normal após 60 dias de pós-operatório.

Endomyocardial biopsy as risk factor in the development of tricuspid insufficiency after heart transplantation

OBJECTIVE

Endomyocardial biopsy (EMB), which is used to monitor for rejection, may cause tricuspid regurgitation (TR) after orthotopic heart transplantation (OHT). The purpose of this investigation was to examine the occurrence of tricuspid valve tissue in myocardial specimens obtained by routine EMB performed after OHT.

PATIENTS AND METHODS

From January 2000 to July 2008, 125 of the patients who underwent OHT survived more than 1 month. Their follow-up varied from 1 month to 8.5 years (mean, 5.1 +/- 3.7 years). EMB was the gold standard examination and myocardial scintigraphy with gallium served as a screen to routinely monitor rejection.

RESULTS

Each of 428 EMB including 4 to 7 fragments, totaling 1715 fragments, were reviewed for this study. The number of EMB per patient varied from 3 to 8 (mean, 4.6 +/- 3.5). Histopathological analysis of these fragments showed tricuspid tissue in 4 patients (3.2%), among whom only 1 showed aggravation of TR.

CONCLUSIONS

EMB remains the standard method to diagnose rejection after OLT. It can be performed with low risk. Reducing the number of EMB using gallium myocardial scintigraphy or other alternative methods as well as adoption of special care during the biopsy can significantly minimize trauma to the tricuspid valve.

Rheumatic heart disease: 15 years of clinical and immunological follow-up

Rheumatic fever (RF) is a sequel of group A streptococcal throat infection and occurs in untreated susceptible children. Rheumatic heart disease (RHD), the major sequel of RF, occurs in 30%-45% of RF patients. RF is still considered endemic in some regions of Brazil and is responsible for approximately 90% of early childhood valvular surgery in the country. In this study, we present a 15-year clinical follow-up of 25 children who underwent surgical valvular repair. Histopathological and immunological features of heart tissue lesions of RHD patients were also evaluated. The patients presented severe forms of RHD with congestive symptoms at a very young age. Many of them had surgery at the acute phase of RF. Histological analysis showed the presence of dense valvular inflammatory infiltrates and Aschoff nodules in the myocardium of 21% of acute RHD patients. Infiltrating T-cells were mainly CD4+ in heart tissue biopsies of patients with rheumatic activity. In addition, CD4+ and CD8+ infiltrating T-cell clones recognized streptococcal M peptides and cardiac tissue proteins. These findings may open the possibilities of new ways of immunotherapy. In addition, we demonstrated that the surgical procedure during acute phase of the disease improved the quality of life of young RHD patients.

Reversible pulmonary trunk banding III: Assessment of myocardial adaptive mechanisms—contribution of cell proliferation

OBJECTIVES

Rapid ventricular conditioning induced by pulmonary artery banding has been recommended for patients with transposition of the great arteries who have lost the chance for the arterial switch operation or whose systemic (right) ventricle failed after the atrial switch. The present study was designed to experimentally evaluate 2 types of pulmonary artery banding (continuous and intermittent) and verify histologically the changes (hypertrophy or hyperplasia or both) of cardiomyocytes and vascular and interstitial cells from the stimulated ventricle beyond the neonatal period.

METHODS

Twenty-one goats, 30 to 60 days old, were divided into 3 groups, each comprising 7 animals, as follows: control group (no surgical procedure); continuously stimulated group (systolic overload maintained for 96 hours); and intermittently stimulated group (4 periods of 12-hour systolic overload, alternated with a resting period of 12 hours). The animals were then killed for histologic and immunohistochemical analysis of the hearts. Murine monoclonal antibody Ki-67 was used as a proliferation cell marker. Myocardial collagen area fraction was determined by Sirius red staining.

RESULTS

For both stimulated groups, a significant increase occurred in right ventricular cardiomyocytes and respective nuclei diameters compared with the controls (P < .05). The number of Ki-67-positive cardiomyocytes and interstitial/vessel cells from the right ventricle was augmented in both trained groups in relation to the left ventricle (P < .05). There was no significant difference in the right ventricular collagen area fraction from both trained groups compared with controls.

CONCLUSIONS

Irrespective of the shorter training time (periods of overload intercalated with resting), the intermittent stimulation regimen was able to produce a similar training of the subpulmonary ventricle compared with the continuous stimulation regarding mass acquisition, cell hypertrophy, and hyperplasia.

Respiratory syncytial virus as a trigger of a pulmonary hypertensive crisis after operative correction of aortic coarctation

We discuss a 9-month-old male baby, submitted to surgery for correction of aortic coarctation, who showed severe bronchospasm, hypoxaemia, and cardio-respiratory arrest, and who died on the fifth postoperative day. The autopsy revealed histological signs of severe pulmonary vasoconstriction, possibly as a consequence of hypoxaemia secondary to bronchiolitis due to infection with the respiratory syncytial virus. This supposition was confirmed when viruses were detected in pulmonary tissue by immunohistochemistry and electron microscopy.

The nomenclature, definition and classification of discordant atrioventricular connections

During the process of creation of a bidirectional crossmap between the system emerging, on the one hand, from the initiative sponsored by the Congenital Heart Committees of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Surgeons, and on the other hand, from that formulated by the Coding Committee of the European Association for Pediatric Cardiology, the Nomenclature Working Group has successfully created the International Paediatric and Congenital Cardiac Code. As would be expected, during the process of crossmapping it became clear that, for most lesions, the European Pediatric Cardiac Code was more complete in its description of the diagnoses, while the International Congenital Heart Surgery Nomenclature and Database Project was more complete in its description of the procedures. This process of crossmapping exemplifies the efforts of the Nomenclature Working Group to create a comprehensive and all-inclusive international system for the naming of paediatric and congenital cardiac disease, the International Pediatric and Congenital Cardiac Code. Although names and classification for paediatric and congenital cardiac disease will continue to evolve over time, we are now closer than ever to reaching uniform international agreement and standardization. The International Paediatric and Congenital Cardiac Code can be downloaded from the Internet, free of charge, at www.ipccc. net.

The nomenclature, definition and classification of hypoplastic left heart syndrome

The hypoplastic left heart syndrome encompasses a spectrum of cardiac malformations that are characterized by significant underdevelopment of the components of the left heart and the aorta, including the left ventricular cavity and mass. At the severe end of the spectrum is found the combination of aortic and mitral atresia, when the left ventricle can be close to non-existent. At the mild end are the patients with hypoplasia of the aortic and mitral valves, but without intrinsic valvar stenosis or atresia, and milder degrees of left ventricular hypoplasia. Although the majority of the patients are suitable only for functionally univentricular repair, a small minority may be candidates for biventricular repair. The nature of the syndrome was a topic for discussion at the second meeting of the International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Heart Disease, the Nomenclature Working Group, held in Montreal, Canada, over the period January 17 through 19, 2003. Subsequent to these discussions, the Nomenclature Working Group was able to create a bidirectional crossmap between the nomenclature initially produced jointly on behalf of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Surgeons, and the alternative nomenclature developed on behalf of the Association for European Paediatric Cardiology. This process is a part of the overall efforts of the Nomenclature Working Group to create a comprehensive and all-inclusive international system of nomenclature for paediatric and congenital cardiac disease, the International Paediatric and Congenital Cardiac Code. In this review, we discuss the evolution of nomenclature and surgical treatment for the spectrum of lesions making up the hypoplastic left heart syndrome and its related malformations. We also present the crossmap of the associated terms for diagnoses and procedures, as recently completed by the Nomenclature Working Group.

Bioeffects of albumin-encapsulated microbubbles and real-time myocardial contrast echocardiography in an experimental canine model

Myocardial contrast echocardiography has been used for assessing myocardial perfusion. Some concerns regarding its safety still remain, mainly regarding the induction of microvascular alterations. We sought to determine the bioeffects of microbubbles and real-time myocardial contrast echocardiography (RTMCE) in a closed-chest canine model. Eighteen mongrel dogs were randomly assigned to two groups. Nine were submitted to continuous intravenous infusion of perfluorocarbon-exposed sonicated dextrose albumin (PESDA) plus continuous imaging using power pulse inversion RTMCE for 180 min, associated with manually deflagrated high-mechanical index impulses. The control group consisted of 3 dogs submitted to continuous imaging using RTMCE without PESDA, 3 dogs received PESDA alone, and 3 dogs were sham-operated. Hemodynamics and cardiac rhythm were monitored continuously. Histological analysis was performed on cardiac and pulmonary tissues. No hemodynamic changes or cardiac arrhythmias were observed in any group. Normal left ventricular ejection fraction and myocardial perfusion were maintained throughout the protocol. Frequency of mild and focal microhemorrhage areas in myocardial and pulmonary tissue was similar in PESDA plus RTMCE and control groups. The percentages of positive microscopical fields in the myocardium were 0.4 and 0.7% (P = NS) in the PESDA plus RTMCE and control groups, respectively, and in the lungs they were 2.1 and 1.1%, respectively (P = NS). In this canine model, myocardial perfusion imaging obtained with PESDA and RTMCE was safe, with no alteration in cardiac rhythm or left ventricular function. Mild and focal myocardial and pulmonary microhemorrhages were observed in both groups, and may be attributed to surgical tissue manipulation.

Classification of the functionally univentricular heart: unity from mapped codes

The nomenclature and classification of patients with a functionally univentricular heart has been debated for decades. We review here the approach taken for dealing with this group of patients by the International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Cardiac Disease. We discuss the approach of this Nomenclature Working Group in the context of other historical and contemporary ideas about this topic.

The current status and future directions of efforts to create a global database for the outcomes of therapy for congenital heart disease

There are many reasons for seeking to create a global database with which to record the outcomes of therapy for congenital heart disease. Such a database can function as a tool to support a variety of purposes:

Doppler flow evaluation can anticipate abnormal left lung perfusion after transcatheter closure of patent ductus arteriosus

AIMS

Coil protrusion into the left pulmonary artery (LPA) has been described after transcatheter closure of the patent ductus arteriosus (PDA). The possible impact of such a finding in lung perfusion has not been completely clarified. We evaluated Doppler flow velocities and lung perfusion in patients submitted to that procedure.

METHODS

After transcatheter closure of PDA with coils, 70 patients (mean age 8.6+/-3.4 years) were followed for a period of 3.6+/-0.9 years (range 2.1-5.9) and compared to 22 controls. Peak flow velocities and coil protrusion were assessed by Doppler echocardiography. A Doppler velocity index (DVI) was calculated by the difference between the LPA and right pulmonary artery (RPA) peak flow velocities relative to the pulmonary trunk (PT) expressed in percentage, as follows: DVI=(LPA velocity - RPA velocity)/PT velocity x 100. Lung scintigraphy was performed using (99m)Tc-labelled macro-aggregated albumin.

RESULTS

Device protrusion was observed in 94% of the patients, 10% of whom presented abnormal left lung perfusion. Peak LPA velocity and DVI were significantly greater in patients (p=0.001) and correlated negatively with left lung perfusion values (R(2)=0.21 and R(2)=0.65, respectively). A cut-off value of 50% for the DVI showed high sensitivity and specificity for reduced lung perfusion.

CONCLUSION

Impaired left lung perfusion may appear following transcatheter closure of PDA with coils and the determination of DVI may anticipate such alteration.

Vascular remodeling process in reversibility of pulmonary arterial hypertension secondary to congenital heart disease

Pulmonary vascular remodeling process was analyzed using morphometry in lung biopsy specimens taken from 26 children, aged 6 to 160 months, who had congenital heart disease and significant pulmonary arterial hypertension. Reparative surgery was performed in 22 patients and palliative surgery was performed in four patients. One patient expired postoperatively and four others after hospital discharge. Vascular remodeling examination revealed a characteristic pathological picture: pronounced medial thickening with increased collagen content (fibrosis), without significant arterial intimal proliferation. At a mean follow-up of 44 months, 72% of the survivors were asymptomatic with no medication. Diagnosed by echocardiogram, 22% of these patients were shown to have pulmonary arterial hypertension. The characteristic pathological features described above occurred in 38% of the patients who either expired or had pulmonary hypertension postoperatively. These findings were an aid to identifying a high risk group in which the outcome does not meet expectations for the classical grade I and II changes. We concluded that the presence of isolated medial thickening does not ensure either survival or a normal postoperative pulmonary arterial pressure at late follow-up and that the collagen content can be a better reference for good outcome. Early intracardiac repair is recommended before the development of significant medial fibrosis.

Double-outlet right ventricle associated with discordant atrioventricular connection and dextrocardia in a cat

The prevalence of congenital cardiac disease in cats varies from 0.2 to 1 per cent, with males being more affected than females. This is probably an underestimate due to the fact that not all affected kittens are presented. Discordant atrioventricular connection (where the morphological right atrium connects to the morphological left ventricle, and the morphological left atrium connects to the morphological right ventricle) is an uncommon condition in humans and, to the authors' knowledge, has not to date been described in animals. The association between this anomaly and the double-outlet right ventricle (where both great arteries arise entirely or partially from the morphological right ventricle) is extremely rare in children. This report describes a case of a cat which presented with this association of cardiac defects.

Methotrexate in acute persistent humoral rejection: an option for graft rescue

Humoral response emerges as an important component in acute graft rejection and a new challenge to clinicians in posttransplant care. Management of recurrent episodes and persistent activation of the humoral component of the immune system, despite the usual therapeutic approach to rejection, remains unknown. This article describes the successful use of methotrexate as an option for rescuing a graft in this worrisome situation.

Ventricular expression of atrial natriuretic peptide in chronic chagasic cardiomyopathy is not induced by myocarditis

BACKGROUND

The ventricles of the normal heart are virtually devoid of atrial natriuretic peptide (ANP). Although ANP occurs in ventricles submitted to elevated wall stress, it is not clear whether ANP expression is affected by myocarditis. We investigated the immunohistochemical expression of ANP in chronic chagasic cardiomyopathy, an inflammatory cardiomyopathy caused by infection with the protozoan Trypanosoma cruzi.

METHODS

Necropsy samples from the left and right ventricles of 16 patients exhibiting chronic chagasic cardiomyopathy were evaluated for myocarditis, fibrosis, T. cruzi parasites and ANP immunoreactivity. The diameters of 50 myocytes per sample were measured.

RESULTS

ANP was present in myocytes of the subendocardial region in 13/16 (81.3%) left and 10/16 (62.5%) right ventricular samples (P=0.25). Myocytes present in the inflammatory foci, near the infiltrating inflammatory cells but distant from the subendocardial region, did not express ANP. Trypanosoma cruzi parasites exhibited intense immunoreactivity for ANP. The mean myocyte diameter and the incidence of myocarditis, fibrosis, and T. cruzi parasites was similar between the left and right ventricular samples. No statistical differences were found between the ANP-positive and ANP-negative cases.

CONCLUSIONS

In chronic chagasic cardiomyopathy, both ventricles exhibit hypertrophy, fibrosis and ANP in the subendocardial region. The inflammatory infiltrate does not induce ANP expression in the myocytes. Regional stress but not myocarditis itself, is probably responsible for ventricular ANP expression in myocarditis.

Reversible pulmonary trunk banding. II. An experimental model for rapid pulmonary ventricular hypertrophy

OBJECTIVE

An experimental model with a reversible pulmonary trunk banding device was developed with the aim of inducing rapid ventricular hypertrophy. The device consists of an insufflatable cuff connected to a self-sealing button.

METHODS

The right ventricles of 7 young goats (average weight, 8.7 kg) were submitted to systolic overload and evaluated according to the hemodynamic, echocardiographic, and morphologic aspects. Baseline biopsy specimens were taken from the myocardium for microscopic analysis. The device was implanted on the pulmonary trunk and inflated so that a 0.7 right ventricular/left ventricular pressure ratio was achieved. Echocardiographic and hemodynamic evaluations were performed every 24 hours. Systolic overload was maintained for 96 hours. The animals were then killed for morphologic study. Another 9 goats (average weight, 7.7 kg) were used for control right ventricular weight.

RESULTS

The systolic right ventricular/pulmonary trunk pressure gradient varied from 10.1 +/- 4.3 mm Hg (baseline) to 60.0 +/- 11.0 mm Hg (final). Consequently, the right ventricular/left ventricular pressure ratio increased from 0.29 +/- 0.06 to 1.04 +/- 0.14. The protocol group showed a 74% increase in right ventricular mass when compared with the control group. Serial 2-dimensional echocardiography showed a 66% increase in right ventricular wall thickness. There was a 24% increase in the mean myocyte perimeter, and the myocyte area increased 61%.

CONCLUSIONS

The device is easily adjustable percutaneously, enabling right ventricular hypertrophy in 96 hours of gradual systolic overload. This study suggests that the adjustable pulmonary trunk banding might provide better results for the 2-stage Jatene operation and for the failed atrial switch operations to convert to the double-switch operation.