Olga Sanz

Risk of embolization after institution of antibiotic therapy for infective endocarditis.

OBJECTIVES This study was designed to assess the risk of systemic embolization in patients with left-sided infective endocarditis, once adequate antibiotic treatment had been initiated, on the basis of prospective clinical follow-up. BACKGROUND As one of the complications of infective endocarditis, embolization has a great impact on prognosis. Prediction of an individual patients risk of embolization is very difficult. METHODS We studied 217 episodes of left-sided endocarditis that were experienced among a cohort of 211 prospectively recruited patients. According to the Duke criteria, 91% of the episodes were definite infective endocarditis. Seventy-two episodes involved infections located on prosthetic valves. All patients were studied by transthoracic and transesophageal echocardiography. Clinical, echocardiographic and microbiologic data were entered in a data base. The mean follow-up interval was 151 days. RESULTS Twenty-eight episodes (12.9%; group I) of endocarditis had embolic events after the initiation of antibiotic therapy. The remaining 189 episodes did not embolize (group II). Most emboli (52%) affected the central nervous system, and 65% of the embolic events occurred during the first two weeks after initiation of antibiotic therapy. Previous embolism was associated with new embolism (relative risk [RR] 1.73, 95% confidence interval [CI] 1.02 to 2.93; p = 0.05). There was an increase in the risk of embolization with increasing vegetation size (RR 3.77, 95% CI 0.97 to 12.57; p = 0.07). Vegetation size had no impact on the risk of embolization in streptococcal endocarditis or aortic infection. By contrast, large (> or = 10 mm) vegetations had a higher incidence of embolism when the microorganism was staphylococcus (p = 0.04) and the mitral valve was infected (p = 0.03). The increase in vegetation size at follow-up showed a higher risk for embolization (RR 2.64, 95% CI 0.98 to 7.16; p = 0.02). CONCLUSIONS Embolism before antimicrobial therapy is a risk factor for new emboli. The risk of embolization seems to increase with increasing vegetation size, and this is particularly significant in mitral endocarditis and staphylococcal endocarditis. An increase in vegetation size, despite antimicrobial treatment, may predict later embolism.

Periannular extension of infective endocarditis

OBJECTIVES This prospective study was designed to assess the current clinical course, risk factors, microbiologic profile and echocardiographic findings of patients with left-sided endocarditis and perivalvular complications. BACKGROUND Periannular complications worsen the prognosis of patients with endocarditis. The relation between these complications and the clinical and microbiologic data has not been clearly defined. METHODS In this clinical cohort study, 211 patients with left-sided endocarditis, according to the Duke criteria, were prospectively recruited. All patients underwent conventional and transesophageal echocardiography. The mean follow-up interval was 151 days. RESULTS Perivalvular complications were detected in 78 patients (37%). The incidence of periannular extension of infection in native and prosthetic valves was 29% and 55%, respectively. The presence of prosthesis (relative risk [RR] 1.88, 95% confidence interval [CI] 1.35 to 2.64) and previous endocarditis (RR 1.78, 95% CI 1.16 to 2.7) were the only pre-existing heart conditions associated with perivalvular complications. Aortic infection (RR 1.8, 95% CI 1.23 to 2.66) and the development of atrioventricular (AV) block (RR 2.55, 95% CI 1.91 to 3.41) were related with the existence of these complications. Coagulase-negative staphylococci were very common in patients with perivalvular complications (RR 1.77, 95% CI 1.21 to 2.59), and small vegetations were more frequent in these patients (RR l.45, 95% CI 0.95 to 2.22). An operation was more frequently performed in patients with perivalvular complications, but mortality was similar in patients with and without these complications. CONCLUSIONS Aortic infection, prosthetic endocarditis, new AV block and coagulase-negative staphylococci were independent risk factors of periannular complications. The period between symptom onset and diagnosis, the incidence of pericardial effusion and persistent signs of infection were similar between patients with and without perivalvular complications. Patients with perivalvular complications did not demonstrate a difference in the presence or size of vegetations or the frequency of embolism. An operation was more frequently performed in these patients, but mortality was similar in both groups.

Valor pronóstico de la ecocardiografía con dobutamina después de un infarto agudo de miocardio no complicado

Introduccion y objetivos. Despues de un infarto es importante detectar a los pacientes con riesgo de eventos adversos. Nuestro objetivo fue valorar la utilidad pronostica de la ecocardiografia con dobutamina tras un infarto no complicado. Metodo. Se realizo ecocardiografia con dobutamina a 125 pacientes (edad media 65 ± 11 anos, el 82% varones) en los primeros diez dias despues de un infarto no complicado. Se consideraron las siguientes respuestas del miocardio: a) negativo; b) mejoria mantenida de la contractilidad; c) mejoria inicial con empeoramiento posterior, y d) empeoramiento de la contractilidad en la zona del infarto o a distancia. Resultados. Con un seguimiento de 7,4 ± 4,6 meses hubo 47 eventos: 3 muertes no cardiacas, 6 muertes cardiacas, 5 infartos, 21 anginas, 2 insuficiencias cardiacas y 10 revascularizaciones. El analisis mediante la prueba de regresion de Cox demostro que el empeoramiento fue el mejor predictor (p Conclusiones. La mejoria mantenida de la contractilidad en la zona del infarto no es predictor de eventos. El empeoramiento de la contractilidad en la zona del infarto o a distancia durante la ecocardiografia con dobutamina en los primeros 10 dias tras un infarto no complicado predice la aparicion de eventos. Por tanto, esta prueba podria emplearse en la estratificacion de riesgo postinfarto.

Safety of coronary stenting early after thrombolysis in patients with acute myocardial infarction: One- and six-month clinical and angiographic evolution

To determine the feasibility and safety of early posthrombolysis coronary stenting and the incidence of further reocclusion, we followed 99 consecutive patients with acute myocardial infarction thrombolyzed with rt‐PA 2.0 ± 0.8 hr after onset. Culprit artery was stented 14.0 ± 7.0 hr after thrombolysis. All patients underwent clinical and angiographic follow‐up at 1 and 6 months. Angiographic success was achieved in 99% of cases. Neither major cardiac events nor bleeding or vascular complications occurred during hospital stay. At 30 days, no events occurred and normal flow persisted in all stented arteries. At 6 months, only one artery reoccluded (1%), resulting in a nonfatal reinfarction. Restenosis rate was 21%. Contribution of the infarcted area to left ventricular function significantly increased from baseline to 30‐day and to 6‐month evaluations. Thus, early posthrombolysis stenting is a safe strategy with a low reocclusion rate, which seems to allow functional recovery of the infarcted area. Further studies are necessary to define its impact on survival and cost‐effectiveness. Cathet Cardiovasc Intervent 2002;55:467–476.

Perfil clínico y pronóstico de los pacientes con endocarditis y seudoaneurismas perianulares

Introduccion y objetivos El proposito de este estudio ha sido conocer el curso clinico y el pronostico de los pacientes con endocarditis que desarrollan un seudoaneurisma. Metodos Se describen las caracteristicas clinicas y evolutivas de un grupo de 18 pacientes (11 varones, edad media 55 ± 4 anos) con endocarditis infecciosa, en quienes la ecografia transesofagica diagnostico la presencia de seudoaneurisma. Resultados Catorce seudoaneurismas se localizaron en posicion aortica (6 sobre valvula nativa y 8 sobre protesis), tres en posicion mitral (tres protesis) y uno en posicion tricuspidea. En 6 casos aparecio bloqueo auriculoventricular que no existia al ingreso, y en todos ellos el seudoaneurisma estaba en posicion aortica. Los microorganismos mas frecuentemente aislados fueron los estafilococos (n = 5) y estreptococos (n = 5). Se encontraron abscesos en 5 pacientes. La presencia de seudoaneurisma no fue considerada per se como criterio de cirugia. De los 11 pacientes operados, 5 fallecieron tras la cirugia (45%), uno presento reinfeccion y otros 5 estan asintomaticos. Los restantes 7 pacientes recibieron exclusivamente tratamiento medico: fallecieron dos (28%), uno presento reinfeccion y cuatro estan asintomaticos. En el grupo de tratamiento conservador que estan asintomaticos (n = 4), el tamano del seudoaneurisma no se modifico despues de 24 meses de seguimiento (diametro mayor 21 ± 5 frente a 22 ± 5 mm en el seguimiento; p = NS). Conclusiones La presencia de seudoaneurisma identifica a un subgrupo de pacientes con endocarditis que tienen una alta mortalidad. Los seudoaneurismas son mas frecuentes en posicion aortica y alrededor de material protesico. El tratamiento medico puede considerarse una alternativa a la cirugia cuando no existan otras indicaciones quirurgicas. Finalmente, el tamano del seudoaneurisma en el grupo de pacientes tratados de forma conservadora permanece estable a lo largo del tiempo.

CHAPTER 2:Experimental Techniques Used for the Characterization of Soft Nanoparticles

This chapter is devoted to current techniques for the characterization of soft nanoparticles. Taking into account the interest of potential readers, i.e., people mainly working in biomedical sciences, only those techniques were selected that assess the most fundamental properties of single nanoparticles, such as their size, shape, surface charge density and internal structure. All of these parameters are relevant for interparticle forces, interactions with other particles or living cells, their capability to encapsulate drugs or the possibility of crossing cellular membranes, among others. For size and shape measurements, not only direct imaging techniques such as scanning and transmission electron microscopy are explained but also indirect techniques such as scattering of light, neutrons or X-rays are presented in sufficient detail. The latter may also be employed to determine molecular weight and radius of gyration. The chapter further describes how to measure the particle surface charge density and to study the ion cloud surrounding charged particles. The usefulness of fluorescence, nuclear magnetic resonance and scattering methods for characterizing the internal structure and the spatial distribution of molecules within nanoparticles is explained at the end of the chapter.