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.

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 percent (P = NS) in the PESDA plus RTMCE and control groups, respectively, and in the lungs they were 2.1 and 1.1 percent, 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.

Evaluation of stunned and infarcted canine myocardium by real time myocardial contrast echocardiography

Differentiation between stunned and infarcted myocardium in the setting of acute ischemia is challenging. Real time myocardial contrast echocardiography allows the simultaneous assessment of myocardial perfusion and function. In the present study we evaluated infarcted and stunned myocardium in an experimental model using real time myocardial contrast echocardiography. Sixteen dogs underwent 180 min of coronary occlusion followed by reperfusion (infarct model) and seven other dogs were submitted to 20 min of coronary occlusion followed by reperfusion (stunned model). Wall motion abnormality and perfusional myocardial defect areas were measured by planimetry. Risk and infarct areas were determined by tissue staining. In the infarct model, the wall motion abnormality area during coronary occlusion (5.52 ± 1.14 cm²) was larger than the perfusional myocardial defect area (3.71 ± 1.45 cm²; P < 0.001). Reperfusion resulted in maintenance of wall motion abnormality (5.45 ± 1.41 cm²; P = 0.43 versus occlusion) and reduction of perfusional myocardial defect (1.51 ± 1.29 cm²; P = 0.004 versus occlusion). Infarct size determined by contrast echocardiography correlated with tissue staining (r = 0.71; P = 0.002). In the stunned model, the wall motion abnormality area was 5.49 ± 0.68 cm² during occlusion and remained 5.1 ± 0.63 cm² after reperfusion (P = 0.07). Perfusional defect area was 2.43 ± 0.79 cm² during occlusion and was reduced to 0.2 ± 0.53 cm² after reperfusion (P = 0.04). 2,3,5-Triphenyl tetrazolium chloride staining confirmed the absence of necrotic myocardium in all dogs in the stunned model. Real time myocardial contrast echocardiography is a noninvasive technique capable of distinguishing between stunned and infarcted myocardium after acute ischemia.

Avaliação da anastomose de artéria torácica intrna esquerda com artéria interventricular anterior pela ecodopplercardiografia / Evaluation of left internal thoracic artery anastomosis with left anterior descending coronary artery by Doppler echocardiography

OBJETIVO - Avaliar o valor do ecocardiograma Doppler (ECO) transtorácico na identificação de perviabilidade da anastomose entre artéria torácica interna esquerda (ATIE) e interventricular anterior, realizada pela técnica de revascularização miocárdica pela minitoracotomia sem circulação extracorpórea. MÉTODOS - Estudaram-se os primeiros 12 pacientes, consecutivos, no período de pós-operatório intra-hospitalar pelo ECO, utilizando-se transdutores de 5 MHz, pela via paraesternal esquerda, preferencial. Foram analisadas velocidades máximas e integrais de velocidade dos componentes sistólico e diastólico das curvas espectrais de fluxo Doppler. Todos pacientes foram submetidos à cinecoronariografia, enquanto hospitalizados. RESULTADOS - O ECO foi exeqüível em 93 'por cento' dos pacientes. Nos com anastomose pérvia (6/7), observou-se ao estudo do Doppler amplo componente diastólico (padrão A). Naqueles com anastomose obstruída (4/4) o padrão observado foi de predomínio sistólico (padrão B) (p=0,003*). CONCLUSÄO - O ECO da ATIE anastomosada com a artéria interventricular anterior, após cirurgia de revascularização miocárdica pela técncia de minitoracotomia, permitiu caracterizar precocemente, com recisão, a pervibilidade da anastomose.

[Prognostic value of stress echocardiography by dobutamine combined with atropine]. / Valor prognóstico da ecocardiografia com estresse pela dobutamina associada à atropina.

PURPOSE: To determine the prognostic value of dobutamine-atropine stress echocardiography (DASE). METHODS: We studied 452 consecutive patients at high risk for coronary artery disease, using DASE. They were followed during a mean period of 23 months. RESULTS: There were 9 cardiac deaths and 2 acute myocardial infarctions in the group of patients with positive tests, and there were 2 myocardial infarctions and 1 cardiac death in patients with negative DASE. CONCLUSION: We conclude that DASE reliably identifies patients at high risk for hard cardiac events.

Valor prognóstico da ecocardiografia com estresse pela dobutamina associada à atropina / Prognostic value of dobutamine-atropine stress echocardiography

OBJETIVO - Avaliar o valor prognóstico para eventos cardíacos maiores da ecocardiografia com estresse pela dobutamina associada à atropina (EEDA). MÉTODOS - Estudados 452 pacientes consecutivos, com alto risco para presença de doença arterial coronária, acompanhados por um período médio de 23 meses. RESULTADOS - Houve 9 mortes cardíacas e 2 infartos agudos do miocárdio em pacientes com EEDA positiva e 2 infartos e 1 morte cardíaca em pacientes com EEDA negativa. CONCLUSÄO - A EEDA é capaz de identificar pacientes de alto risco para eventos maiores.

[Safety and feasibility of dobutamine-atropine stress echocardiography]. / Segurança e exeqüibilidade da ecocardiografia com estresse pela dobutamina associada à atropina.

PURPOSE: To study the safety and feasibility of dobutamine-atropine stress echocardiography (DASE) in patients with known or suspected coronary artery disease. METHODS: There were 3,000 DASE that were studied in a prospective fashion. All symptoms and side effects were stored in a data base format. RESULTS: Major test-related complications observed included one case of myocardial infarction, four cases of sustained ventricular tachycardia and five cases of atropine intoxication. There was no death or ventricular fibrillation as a direct or indirect consequence of the test. The infusion protocol allowed to us to examine patients using beta blockers, and led to 95% feasibility. CONCLUSION: DASE is a safe and feasible method for the study of patients with suspected or known coronary artery disease.

[Diagnostic accuracy of dobutamine-atropine stress echocardiography]. / Acurácia diagnóstica da ecocardiografia com estresse pela dobutamina associada à atropina.

PURPOSE: To analyze the diagnostic accuracy of dobutamine-atropine stress echocardiography. METHODS: We studied 304 consecutive patients using dobutamine-atropine stress echocardiography who underwent coronary angiography within a month of the exam. Patients received high dobutamine doses associated or not with atropine. RESULTS: The global sensitivity was 92%, specificity was 72% and diagnostic accuracy was 87%. Analyzing 120 patients with normal LV function, we found sensitivity of 85%, specificity of 79% and accuracy of 82%. CONCLUSION: Dobutamine-atropine stress echocardiography is an accurate method for the detection of coronary artery disease.

[Assessment of left internal thoracic artery anastomosis with left anterior descending coronary artery by Doppler echocardiography]. / Avaliação da anastomose de artéria torácica interna esquerda com artéria interventricular anterior pela ecodopplercardiografia.

PURPOSE: To study the value of Doppler echocardiography as a tool for the evaluation of left internal thoracic artery graft (LITAG) patency in patients who underwent coronary revascularization using minimally invasive bypass surgery without extracorporeal circulation. METHODS: The first 12 consecutive patients were studied after coronary artery bypass surgery using a 5 MHz Doppler transducer. Doppler signals for the systolic and diastolic flow velocities were preferably obtained in the second intercostal space. All patients underwent coronary angiography while hospitalized. RESULTS: The exam was feasible in 93% of patients. Doppler flow pattern was predominantly diastolic (pattern A) in patients with patent anastomoses (6/7). In patients with occluded anastomoses (4/4) Doppler flow pattern was predominantly systolic (pattern B) (p = 0.003). CONCLUSION: Internal thoracic artery flow pattern as measured by Doppler echocardiography after minimally invasive coronary artery bypass graft surgery is an accurate method for identifying LITAG patency.

[Detection of myocardial ischemia during dobutamine stress echocardiography. Correlation with coronary cineangiography]. / Detecção de isquemia miocárdica através de ecocardiografia de estresse com dobutamina. Correlação com cinecoronariografia.

PURPOSE: To detect myocardial ischemia during dobutamine stress echocardiography (DSE). METHODS: Two hundred and seventy one patients were studied; 63 (23%) underwent coronary angiography within a month of DSE. Angiograms were analyzed independently by 3 angiographers, and coronary lesions larger than 50% of luminal occlusion were considered likely to cause ischemia. RESULTS: The global sensitivity and specificity were 95% and 75% respectively, with 89% accuracy. Of 43 patients showing obstructive coronary artery disease, there were 2 false negatives. One of 5 false positives had ischemic cardiomyopathy and another a technically difficult exam. The symptoms and side effects in decreasing order of occurrence are as follows: palpitation 46%; arrhythmia 24%; mild hypotension 24%; chest pain 8%; hypertension 5%; facial paresthesia 4%; chills 1.8%; nausea 1.8%; headache 1.4%; dyspnea 0.4% and severe hypotension 0.4%. CONCLUSION: Considering the results, the small number of complications and the feasibility, DSE seems to be a safe and promising method for detecting myocardial ischemia.