Reperfusión mecánica simple en el infarto agudo de miocardio: Determinantes, implicaciones en el pronóstico y relación con la histología del trombo / Simple mechanical reperfusion in acute myocardial infarction: determinants, prognostic implications and relation with thrombus histology

La reperfusión mecánica simple (RMS) es la lograda en la angioplastia primaria al atravesar la oclusión en la arteria responsable de infarto con la guía intracoronaria. Para evaluar los determinantes de la RMS, su implicación en el pronóstico y su relación con la histopatología del trombo rescatado, fueron analizados los casos de 601 pacientes con infarto agudo de miocardio con elevación del segmento ST y oclusión total de la arteria responsable de infarto (flujo TIMI 0). Se consideraron dos grupos según la presencia de RMS, definida por la visualización de contraste distal a la lesión luego de atravesarla con la guía intracoronaria. Se realizó el análisis histopatológico de los trombos en un subgrupo de 160 pacientes tratados con tromboaspiración. En 303 (50.4%) pacientes se obtuvo RMS. La RMS se asoció a menor ventana al tratamiento (248 vs. 286 minutos, p = 0.001), menor deterioro de la función sistólica ventricular izquierda inicial y shock al ingreso (9.2 vs.16.4%, p = 0.008), mayor tasa de éxito (94.7 vs. 78.5%, p < 0.0001) y de rescate de trombos (70/81 vs. 27/79 pacientes, p < 0.0001). La arteria responsable de infarto más frecuente fue la coronaria derecha. La RMS se asoció con menor tamaño del trombo, menor concentración de leucocitos y eritrocitos y mayor contenido de células inflamatorias, cristales de colesterol y colágeno provenientes de la placa. La RMS es un predictor independiente de éxito y su relación con la anatomía del trombo podría redefinir la indicación de la tromboaspiración.

Simple mechanical reperfusion (SMR) is defined as reperfusion achieved after wire insertion at the occluded infarct-related artery in primary angioplasty. The determinants and prognostic implications of SMR and its relationship with the histopathology of the rescued thrombus were evaluated in 601 patients with acute myocardial infarction showing ST elevation and pre-procedural total occlusion of the infarct-related artery (TIMI flow 0). Two groups were considered according to the presence of SMR, defined as the visualization of contrast material after crossing the occlusion with the guide wire. SMR was achieved in 303 patients (50.4%) and was found to be associated with less time to treatment (248 vs. 286 minutes; p = 0.001), less deteriorated initial left ventricular function and shock at admission (9.2 vs. 16.4%; p = 0.008), higher successful rate (94.7% vs. 78.5%; p < 0,0001) and of higher rate of thrombus rescue: 70/81 vs. 27/79 patients (p < 0.0001). The right coronary artery was the most frequent infarct-related artery. Histopathology of the retrieved thrombi was available for 160 patients treated with thrombus aspiration. SMR was associated with smaller thrombus, lower contents of leukocytes and erythrocytes, and higher thrombus content of inflammatory cells, cholesterol and collagen crystals from the atheromatous plaque. SMR is an independent predictor of procedure success and its relationship with the anatomy of the thrombus could redefine the indication of thrombus aspiration.

Significado clínico de características histológicas de trombos de pacientes com infarto do miocárdio / Clinical significance of histological features of thrombi in patients with myocardial infarction

FUNDAMENTO: A Intervenção Coronariana Percutânea (ICP) é a estratégia mais utilizada para o tratamento do Infarto Agudo do Miocárdio com elevação do segmento ST (IAMCST), e a tromboaspiração vem sendo crescentemente utilizada para remoção dos trombos oclusivos. OBJETIVOS: Analisar a influência de características histopatológicas de trombos coronarianos nos desfechos clínicos de pacientes com IAMCST, e associação dessas variáveis com características clínicas, angiográficas, laboratoriais e medicamentos utilizados na internação hospitalar. MÉTODOS: Estudo de coorte prospectivo. Todos os pacientes foram acompanhados na internação hospitalar e por até 30 dias após o evento. Os trombos aspirados foram conservados em formol e posteriormente corados por hematoxilina-eosina e incluídos em parafina. Os trombos foram classificados em recentes e antigos. O desfecho primário foi a ocorrência de eventos cardiovasculares maiores em 30 dias. RESULTADOS: No período do estudo, foram avaliados 1.149 pacientes com IAMCST, e 331 pacientes foram submetidos a aspiração de trombos, ficando disponíveis para análise 199 pacientes. Foram identificados trombos recentes em 116 pacientes (58%) e trombos antigos em 83 pacientes (42%). Os trombos recentes apresentaram maior infiltração de hemácias do que os trombos antigos (p = 0,02), mas não houve diferenças estatisticamente significativas entre as demais características clínicas, angiográficas, laboratoriais, histopatológicas e medicamentos nos dois grupos de pacientes. As taxas de desfechos clínicos foram similares nos dois grupos. CONCLUSÕES: Os trombos recentes foram identificados em 58% dos pacientes com IAMCST e observou-se associação com infiltração de hemácias. Não houve associação entre as características histopatológicas dos trombos e variáveis clínicas e desfechos cardiovasculares.

BACKGROUND: Percutaneous Coronary Intervention (PCI) is the most common strategy for the treatment of Acute ST segment elevation Myocardia Infarction (STEMI), and thromboaspiration has been increasingly utilized for removal of occlusive thrombi. OBJECTIVES: To analyze the influence of histopathological features of coronary thrombi in clinical outcomes of patients with STEMI, and the association of these variables with clinical, angiographic, and laboratory features and medications used in hospitalization. METHODS: Prospective cohort study. All patients were monitored during hospitalization and thirty days after the event. Aspirated thrombi were preserved in formalin and subsequently stained with hematoxylin-eosin and embedded in paraffin. Thrombi were classified as recent and old. The primary outcome was the occurrence of major cardiovascular events within thirty days. RESULTS: During the study period, 1,149 patients were evaluated with STEMI, and 331 patients underwent thrombi aspiration, leaving 199 patients available for analysis. It was identified recent thrombi in 116 patients (58%) and old thrombi in 83 patients (42%). Recent thrombi have greater infiltration of red blood cells than old thrombi (p = 0.02), but there were no statistically significant differences between other clinical, angiographic, laboratory, and histopathological features and medications in both group of patients. The rates of clinical outcomes were similar in both groups. CONCLUSIONS: Recent thrombi were identified in 58% of patients with STEMI and it was observed an association with infiltration of red blood cells. There was no association between histopathological features of thrombi and clinical variables and cardiovascular outcomes.

Pathological characteristics of sudden death caused by coronary thrombosis / 法医学杂志

OBJECTIVE@#To explore medico-legal characteristics of sudden death caused by coronary heart disease combined with coronary thrombosis.@*METHODS@#Ninety-six cases of sudden death caused by coronary heart disease were collected and divided into two groups: thrombus positive and thrombus negative groups. The time onset, induction and pathological features of coronary artery disease were analyzed.@*RESULTS@#Two groups showed man-dominant population. There were no statistical significant differences in season, circadian rhythm and induction factor. The thrombus positive group (age < 40) showed a higher disease incidence. Heart weight and degree of coronary stenosis were lower in thrombus positive group. However, there was no statistical difference in the number of atherosclerotic coronary arteries (> or = 2), the length of coronary lesions and myocardial infarct. But thrombosis positive group showed lower tendency.@*CONCLUSION@#Two groups are man-dominant population and similar induction factor, lesion position, mechanism of death. But thrombus positive group appeared more in a younger population and the degree of coronary stenosis is milder than thrombus negative group. Forensic pathologists should pay more attention to these characteristics in death investigation.

Trombectomia na angioplastia primária em ponte de safena / Thrombectomy in primary angioplasty related to a saphenous graft

O emprego da trombectomia na angioplastia primária demonstra bons resultados clínicos e angiográficos imediatos, por meio de redução da embolização distal e do fenômeno do no-reflow e otimização da perfusão miocárdica. Essa técnica, principalmente usada em artérias coronárias, em pontes de safena aortocoronarianas. Relatamos o caso de um paciente de 67 anos com infarto agudo do miocárdio relacionado a oclusão de ponte de safena e submetido a trombectomia com bons resultados.

Thrombectomy in primary angioplasty has demonstrated good early clinical and angiographic outcomes, preventing distal embolization and the "no-reflow" phenomenon and optimizing myocardial perfusion. This technique is frequently used in native coronary arteries and is rarely reported in coronary grafts. We report the case of a 67-year-old male patient with acute myocardial infarction related to the occlusion of a saphenous vein graft submitted to thrombectomy with good results.

Vulnerable plaques, inflammation and newer imaging modalities.

Currently, inflammation is considered to be the central player in the pathogenesis of atherosclerosis. It leads to the formation of multiple plaques in the arterial beds including coronary vasculature. Recent studies using the latest imaging techniques have shown that in patients with acute coronary syndromes (ACS) multiple plaques are ruptured and have thrombus formation on them. Various factors make these plaques unstable, these include structural components of plaque like thin fibrous cap, high lipid content of the plaque core and inflammation, both localized and generalized. It has been shown that most of the ACS are caused by plaques causing non-critical stenosis as seen on traditional X-ray angiography. Also, the phenomenon of remodelling makes angiography a poor technique for plaque visualization. Hence newer modalities are required to identify these "vulnerable plaques". Intravascular ultrasound (IVUS), thermography and Magnetic Resonance Imaging (MRI) are a few such promising techniques. Here we review the invasive and non-invasive modalities that can be helpful in the identification of these plaques before they become unstable and cause ACS, and also the available therapies to stabilize these plaques.

Aspirina, ticlopidina ou clopidogrel? / Aspirin, ticlopidine or clopidogrel?

Os quadros isquêmicos miocárdicos agudos iniciam-se a partir da formação do trombo sobre a placa aterosclerótica. Em circunstâncias em que ocorre lesão endotelial - ruptura da placa - , a adesão, a ativação e a agregação das plaquetas desencadeiam o processo de formação do trombo. O objetivo da terapêutica antiplaquetária nas síndromes isquêmicas agudas é modificar as funções da plaqueta no sentido de inibir a formação e o desenvolvimento do trombo arterial sem prejuízo da hemostasia. Entre as substâncias antiplaquetárias destaca-se a aspirina, que atua impedindo a formação da tromboxane A2, que é importante no processo de formação do trombo. A aspirina, comprovadamente, trouxe grande impacto na modificação da evolução clínica dos pacientes com angina instável ou infarto agudo do miocárdio. Os derivados tienopiridínicos, ticlopidina e clopidogrel, agem inibindo a ação do difosfato de adenosina e, portanto, impedindo a ativação plaquetária. Importantes estudos clínicos demonstraram que esses fármacos apresentam benefícios comparáveis aos da aspirina. São, portanto, recomendados na impossibilidade de se utilizar esta última. Os dados dos estudos que avaliam os efeitos da associação dos tienopiridínicos com a aspirina demonstram as vantagens de se atuar concomitantemente em mecanismos diferentes da ativação das plaquetas para a prevenção de eventos isquêmicos miocárdicos, tanto no contexto dos procedimentos invasivos como no tratamento clínico da angina instável.

Detection of Mycoplasma pneumoniae and Chlamydia pneumoniae in ruptured atherosclerotic plaques

This paper reports what is apparently the first observation of Mycoplasma pneumoniae in association with Chlamydia pneumoniae in thrombosed ruptured atheromas. We performed electron microscopy and in situ hybridization in specimens from three patients who died of acute myocardial infarction. These patients had typical symptoms of acute ischemic syndrome. Mycoplasmas were present mainly in the lipid core of the ruptured thrombosed plaque. Vulnerable atheromas are rich in cholesterol and may favor the growth of mycoplasmas, the only microorganisms that require cholesterol for survival. We suggest that the association of Mycoplasma pneumoniae and Chlamydia pneumoniae may increase the virulence of these microorganisms, favoring proliferation, plaque inflammation and possibly plaque rupture

Correlation of Braunwald's clinical classification of unstable angina pectoris with angiographic extent of disease, lesion morphology and intra-luminal thrombus.

One hundred consecutive patients (81 male and 19 female) with unstable angina pectoris undergoing coronary angiography were divided according to Braunwald's clinical classification. Seventeen (17%) patients had new onset angina (class I), 68 (68%) sub-acute angina (class II) and 15 (15%) had acute rest angina (class III). Twenty-seven (27%) patients had secondary unstable angina pectoris (class A), 49 (49%) primary unstable angina (class B) and 24 (24%) had post-infarction unstable angina (class C). ST-T wave changes on ECG were present in 54 (54%) while absent in 46 (46%) patients. On coronary angiography, 26 (26%) patients had single vessel disease, 30 (30%) double vessel disease and 39 (39%) patients had triple vessel disease. Five (5%) patients were found to have normal coronaries. Classification of patients according to Braunwald's clinical classification showed single vessel disease to be higher in class I as compared to class II (47% vs 22%; p = 0.04) and classes III (47% vs 20%; p<0.01). Single vessel disease was found to be higher in class C as compared to class B (41.7% vs 16.4; p = 0.01). Double vessel disease was higher in class B as compared to class A (40.8% vs 18.5%, p = 0.04). Triple vessel disease incidence was not found to be significantly different among different clinical classes. Morphology of coronary artery lesions was classified according to Ambrose's classification. Out of the total of 248 lesions in the whole study group, there were 68 (27.42%) concentric lesions, 55 (22.18%) eccentric type I lesions, 23 (9.27%) eccentric type II lesions, 42 (16.94%) multiple irregularity lesions and 60 (24.19%) totally occluded lesions. Concentric lesions were found to be higher in class C as compared to class B (40% vs 19.8%; p = 0.014). Statistically significant difference was not present in the distribution of other morphological type of lesions among different clinical classes. In the whole study group, intra-luminal thrombus was found to be present in 17 (17%) of patients. Distribution of intra-luminal thrombus according to Braunwald's classification showed that none of the patients in class I had intra-luminal thrombus, while 13 (19.1%) patients in class II and 4(26.7%) in class III had intra-luminal thrombus. The difference in the occurrence of intra-luminal thrombus between class I and class II (p = 0.004) and class I and class III (p = 0 .03 was found to be significant. Thus, majority of patients undergoing coronary angiography had primary sub-acute rest angina. Single vessel disease was higher in new onset angina. Patients with unstable angina pectoris and ST-T changes on ECG had higher number of lesions per patient and higher eccentric type I lesions. Intra-luminal thrombus was more frequently encountered with acute rest angina. However, the distribution of different morphological type of lesions on coronary angiography did not differ significantly in different clinical classes of unstable angina pectoris divided according to Braunwald's classification.

Infarto do miocárdio: comparaçäo dos achados anátomo-patológicos em coraçäo com e sem aterosclerose coronária grave em 194 casos de necrópsia / Myocardial infarction: comparison of pathological findings from hearts with and without severe coronary atherrosclerosis in 194 necropsy cases

Objetivo ­ Comparar as características morfológicas do infarto do miocárdio (IM) de pacientes com aterosclerose coronária causando obstrução da luz superior (com aterosclerose grave ­ AG) e inferior a 70% (sem AG). Métodos ­ 194 corações obtidos em necrópsia consecutivas de pacientes gue morreram por IM com idade entre 21 e 82 (média 60) anos, sendo 174 com e 20 sem AG. Resultados ­ A idade média no grupo com Ag foi 56 e a mediana 59 anos; no outro grupo, a média foi de 60 e a mediana 61 anos, havendo diferença significativa na distribuição etária (p = 0,023), com maior quantidade de pacientes abaixo de 40 anos no grupo sem AG. Não houve diferença significativa quanto ao sexo (31,0% de mulheres no grupo com AG e 35,0% no grupo sem AG, p = 0,718), peso médio do coração (com AG 500 g, sem AG 560 g), distribuição dos casos conforme tendo infarto recente apenas, infarto antigo apenas ou ambos (com AG - 36,2%, 28,2% e 35,6% respectivamente; sem AG - 45,0%, 20,0% e 35,0% respectivamente; p = 0,666), paredes acometidas pelos IM (p = 0,715), incidência de infarto hemorrágico (com AG­8,6%, sem AG - 15,0%, p = 0,406), de ruptura de ventrículo esquerdo (com Ag­5,2%, sem AG­10,0%, p = 0,719) e de aneurisma dessa câmara (com AG - 12,1%, sem AG - 15%, p = 0,316). Encontrouse associação entre AG e trombose coronária (trombose antiga recanalizada­p < 0,0001; trombose recente­p = 0,046), que todavia existia quando se restringiu a comparação à trombose recente nos casos não-operados de IM agudo (p = 0,091). Conclusão O grau de obstrução coronária superior ou não a 70% não condicionou diferenças morfológicas significativas em casos fatais de IM. Este dado sugere que esse fator não altera de maneira importante a história natural do IM.

Purpose ­ To compare morphological features of myocardial infarction (MI) from patients with any epicardial coronary artery narrowed at some point more then 70% (severe coronary atherosclerosis­SCA) with those from patients with either no coronary atherosclerosis or only mild (less than 70%) atherosclerosis. Methods ­ Necropsy findings from 194 patients who died due to MI, 174 patients with and 20 without SCA. Ages ranged from 21 to 82 (mean 60) years. Results ­ Mean age was 60 years in the cases with SCA and 56 in the case without it; nevertheless, age distribution was different (p = 0,023), due to the existence of more patients under age 40 in the group without SCA. There was no significant difference concerning sex (31.0% of female patients in the group with SCA and 35,0% in the other group, p = 0.718), mean heart weight (500 g and 506 g), distibution of cases according to time of evolution of MI in recent only, old only or both (cases with SCA - 36.2%, 28.2% and 35.6%; cases without SCA - 45.0% and 20%; p = 0,666), left ventricular wall commited by the MI (p=0.715), incidence of hemorrhagic infarction (with SCA - 8.6%; without SCA - 15.0%; p = 0.406), left ventricular rupture (with SCa - 5.17%, without SCA - 10.0%; p = 0.719) and left ventricular aneurysms (with SCA­12.1%, without SCA - 15.0%; p = 0,316). An association was found between coronary ahterosclerosis and recent (p=0,046) and recanalized (p<0.001) thrombosis, but absent when only recent thrombosis and non-operated cases with recent MI were considered (p = 0.091). Conclusion Necropsy of fatal cases of MI were not signifícantly different in the presence or absence of severe atherosclerotic narrowing (>70%) of epicardial coronary arteries, suggesting that this factor does not modify the natural history of MI.

Infarto agudo do miocárdio fatal em jovem viciado em cocaína / Fatal myocardial infarction in a young cacaine user

Homem de 28 anos de idade, viciado no uso de cocaína endovenosa, sofreu dor torácica causada por infarto do miocárdio fatal, na ausência de aterosclerose coronariana. A necrópsia revelou múltiplos infartos do miocárdio de diferentes tempos de evoluçäo. As artérias coronárias evidenciaram espessamento fibroelástico da cama íntima com trombose recente oclusiva na artéria coronária direita. Portanto, no diagnóstico diferencial da dor torácica ou de alteraçäo hemodinâmica em viciados em cocaína, mesmo jovens, deve-se incluir o infarto agudo do miocárdio

A 28 year-old male cocaine abuser without coronary atherosclerosis sufferedfatal myocardial infarction. Necropsy revealed several myocardial infarctions of different ages. Examination of the coronary arteries revealed fibrointimal thickening of the intimal layer of the coronary arteries.