Javiera González

Seguimiento clínico en pacientes con buena capacidad metabólica en la prueba de esfuerzo con SPECT miocárdico

BACKGROUND The evaluation of coronary artery disease (CAD) can be performed with stress test and myocardial SPECT tomography. AIM To assess the predictive value of myocardial SPECT using stress test for cardiovascular events in patients with good exercise capacity. MATERIAL AND METHODS We included 102 males aged 56 ± 10 years and 19 females aged 52 ± 10 years, all able to achieve 10 METs and ≥ 85% of the theoretical maximum heart rate and at least 8 min in their stress test with gated 99mTc-sestamibi SPECT. Eighty two percent of patients were followed clinically for 33 ± 17 months. RESULTS Sixty seven percent of patients were studied for CAD screening and the rest for known disease assessment. Treadmill stress test was negative in 75.4%; 37% of patients with moderate to severe Duke Score presented ischemia. Normal myocardial perfusion SPECT was observed in 70.2%. Reversible defects appeared in 24.8% of cases, which were of moderate or severe degree (> 10% left ventricular extension) in 56.6%. Only seven cases had coronary events after the SPECT. Two major (myocardial infarction and emergency coronary revascularization) and 5 minor events (elective revascularization) ere observed in the follow-up. In a multivariate analysis, SPECT ischemia was the only statistically significant parameter that increased the probability of having a major or minor event. CONCLUSIONS Nearly a quarter of our patients with good exercise capacity demonstrated reversible defects in their myocardial perfusion SPECT. In the intermediate-term follow-up, a low rate of cardiac events was observed, being the isotopic ischemia the only significant predictive parameter.

Efecto de la temperatura, el estrés hídrico y luminoso sobre la heterogeneidad del fotosistema II en cuatro variedades de poroto (Phaseolus vulgaris L.)

Las plantas superiores, requieren de mecanismos que permitan proteger a los centros fotosinteticos de dano oxidativo, particularmente en condiciones ambientales que determinen una absorcion luminosa en exceso de su capacidad de utilizacion fotoquimica, como son las altas intensidades de luz, propiamente tal, restriccion de agua y aumentos de temperatura. En el mediano y largo plazo los centros PSII tendrian la capacidad de modificar su localizacion y estructura, formando los centros PSII del tipo s y los estados de transicion, cuya variacion no depende, exclusivamente, de la intensidad luminosa. En el presente estudio se determino el efecto de distintos estreses ambientales sobre la heterogeneidad del PSII, en cuatro cultivares de poroto: Arroz Tuscola (AT), Orfeo INIA (OI), Bayos Titan (BT) y Hallado Dorado (HD). En plantas desarrolladas en camaras de crecimiento, la proporcion de centros PSIIs aumento hasta en un 100 % en la medida que se incremento la temperatura. Dicho efecto fue magnificado por el estres hidrico, en estas plantas. En condiciones de campo, el estres luminico impuesto por la fijacion de foliolos a la posicion horizontal, aumento aun mas el efecto del estres hidrico sobre la proporcion de tales centros, desde un 27 %, en plantas regadas y hoja en posicion normal, hasta un 63 % en plantas estresadas y hojas forzadas a la horizontalidad. En cuanto a los estados de transicion, se observo, en plantas desarrolladas a 20 oC en camaras de crecimiento, un aumento de estos al someter sus hojas a 15 oC. Asi mismo, temperaturas de 25 a 35 oC indujeron aumentos en los estados de transicion. El estres hidrico, en los cultivares AT y OI, aminoro la magnitud del efecto de la temperatura, al contrario de lo observado en BT. En el cultivar HD, no se distingue un efecto claro del estres hidrico, sobre la formacion de los estados de transicion inducidos por cambios en la temperatura. Aun cuando existen diferencias en la magnitud de los cambios observados en las diferentes variedades de poroto, en todos ellos se aprecia la tendencia a modificar la estructura de los centros PSII, de manera de favorecer una menor sobreexcitacion de los centros de reaccion de dichos complejos, en las situaciones de estres estudiadas

Estratificación de riesgo de muerte a mediano plazo de pacientes evaluados por enfermedad coronaria con SPECT de perfusión miocárdica bajo efecto de dipiridamol

BACKGROUND Dipyridamole (DIP) is the most commonly employed pharmacological stressor for myocardial perfusion tomography (SPECT) in patients unable to reach an adequate work load. AIM To assess the predictive capacity of DIP SPECT on survival. MATERIAL AND METHODS We included 985 adults aged 66 ±11 years (45% women) with rest and DIP-SPECT. The main indications for the procedure were coronary artery disease (CAD) screening in 66% and known CAD in 33%. Participants were followed up for a median of 65 months (interquartile range 54 to 86 months). During the follow up, 261 deaths were recorded and 98% had a specified cause in their death certificate. RESULTS Myocardial SPECT was abnormal in 44% of participants. Transient ischemic defects were observed in 34%, fixed defects concordant with infarction in 27% and post-stress systolic dysfunction in 23%. Twenty five percent of deaths were attributable to cardiac or ischemic cause and 22% to cancer. In a bivariate analysis, the hazard ratio (HR) of death of any cause was lower in females and higher in the presence of CAD. The multivariate analysis showed that being older than 46 years increased the HR of death of any cause. In a bivariate analysis, the HR for cardiac death was higher when the myocardial SPECT showed ischemia, necrosis or left ventricular dilation. In the multivariate analysis, post-stress left ventricular systolic function was associated with a lower risk of cardiac death. CONCLUSIONS An abnormal myocardial SPECT, perfusion abnormalities, left ventricular systolic function or dilation are independent predictors of cardiac death in these participants.

Linfonodo centinela en cáncer de mama: correlación entre detección isotópica y quirúrgica

BACKGROUND Sentinel node detection localizes the first node that drains a malignant lesion aiming to detect tumor dissemination. AIM To assess the yield of sentinel node detection in breast cancer, using pre or intraoperative scintigraphy. MATERIAL AND METHODS Review of medical records of patients with breast cancer who had a scintigraphic detection of sentinel nodes. Lymph node scintigraphy and surgery were performed in the same day. RESULTS We studied 174 women aged 53 ± 13 years, operated with a diagnosis of breast cancer, including six highly suspicious lesions in the contralateral breast (totaling 180 studied breasts). Preoperative scintigraphy showed a sentinel node in 174 of 180 breasts (97%). Intraoperative gamma probe confirmed the presence of the sentinel node in the same 174 breasts and detected an additional one reaching a detection yield of 97%. Four patients in whom a sentinel node was not detected in the preoperative scintigraphy, had macrometastases. Frozen section biopsies were available in 177 of 180 breasts. Metastases were informed in 45 patients who underwent axillary lymph node dissection, plus one additional patient with a suspicious lesion. CONCLUSIONS A high rate of sentinel node detection in the preoperative scintigraphy was observed. Most sentinel nodes not detected with nuclear medicine had macrometastases. In 71% of patients, the detection of sentinel node avoided axillary lymph node dissection.Background: Sentinel node detection localizes the first node that drains a malignant lesion aiming to detect tumor dissemination. Aim: To assess the yield of sentinel node detection in breast cancer, using pre or intraoperative scintigraphy. Material and methods: Review of medical records of patients with breast cancer who had a scintigraphic detection of sentinel nodes. Lymph node scintigraphy and surgery were performed in the same day. Results: We studied 174 women aged 53 ± 13 years, operated with a diagnosis of breast cancer, including six highly suspicious lesions in the contralateral breast (totaling 180 studied breasts). Preoperative scintigraphy showed a sentinel node in 174 of 180 breasts (97%). Intraoperative gamma probe confirmed the presence of the sentinel node in the same 174 breasts and detected an additional one reaching a detection yield of 97%. Four patients in whom a sentinel node was not detected in the preoperative scintigraphy, had macrometastases. Frozen section biopsies were available in 177 of 180 breasts. Metastases were informed in 45 patients who underwent axillary lymph node dissection, plus one additional patient with a suspicious lesion. Conclusions: A high rate of sentinel node detection in the preoperative scintigraphy was observed. Most sentinel nodes not detected with nuclear medicine had macrometastases. In 71% of patients, the detection of sentinel node avoided axillary lymph node dissection.