A stochastic model of blood flow to calculate blood dose during radiotherapy.

Purpose. Lymphopenia is a common side effect in patients treated with radiotherapy, potentially caused by direct cell killing of circulating lymphocytes in the blood. To investigate this hypothesis, a method to assess dose to circulating lymphocytes is needed.Methods. A stochastic model to simulate systemic blood flow in the human body was developed based on a previously designed compartment model. Blood dose was obtained by superimposing the spatiotemporal distribution of blood particles with a time-varying dose rate field, and used as a surrogate for dose to circulating lymphocytes. We discuss relevant theory on compartmental modeling and how to combine it with models of explicit organ vasculature.Results. A general workflow was established which can be used for any anatomical site. Stochastic compartments can be replaced by explicit models of organ vasculatures for improved spatial resolution, and tumor compartments can be dynamically assigned. Generating a patient-specific blood flow distribution takes about one minute, fast enough to investigate the effect of varying treatment parameters such as the dose rate. Furthermore, the anatomical structures contributing most to the overall blood dose can be identified, which could potentially be used for lymphocyte-sparing treatment planning.Conclusion. The ability to report the blood dose distribution during radiotherapy is imperative to test and act upon the current paradigm that radiation-induced lymphopenia is caused by direct cell killing of lymphocytes in the blood. We have built a general model that can do so for various treatment sites. The presented framework is publicly available athttp://github.com/mghro/hedos.

Fetal and Maternal Atomic Bomb Survivor Dosimetry Using the J45 Pregnant Female Phantom Series: Considerations of the Kneeling and Lying Posture with Comparisons to the DS02 System.

ABSTRACT: Organ dosimetry data of the atomic bomb survivors and the resulting cancer risk models derived from these data are currently assessed within the DS02 dosimetry system developed through the Joint US-Japan Dosimetry Working Group. In DS02, the anatomical survivor models are limited to three hermaphroditic stylized phantoms-an adult (55 kg), a child (19.8 kg), and an infant (9.7 kg)-that were originally designed for the preceding DS86 dosimetry system. As such, organ doses needed for assessment of in-utero cancer risks to the fetus have continued to rely upon the use of the uterine wall in the adult non-pregnant stylized phantom as the dose surrogate for all fetal organs regardless of gestational age. To address these limitations, the Radiation Effects Research Foundation (RERF) Working Group on Organ Dose (WGOD) has established the J45 (Japan 1945) series of high-resolution voxel phantoms, which were derived from the UF/NCI series of hybrid phantoms and scaled to match mid-1940s Japanese body morphometries. The series includes male and female phantoms-newborn to adult-and four pregnant female phantoms at gestational ages of 8, 15, 25, and 38 wk post-conception. In previous studies, we have reported organ dose differences between those reported by the DS02 system and those computed by the WGOD using 3D Monte Carlo radiation transport simulations of atomic bomb gamma-ray and neutron fields for the J45 phantoms series in their traditional "standing" posture, with some variations in their facing direction relative to the bomb hypocenter. In this present study, we present the J45 pregnant female phantoms in both a "kneeling" and "lying" posture and assess the dosimetric impact of these more anatomically realistic survivor models in comparison to current organ doses given by the DS02 system. For the kneeling phantoms facing the bomb hypocenter, organ doses from bomb source photon spectra were shown to be overestimated by the DS02 system by up to a factor of 1.45 for certain fetal organs and up to a factor of 1.17 for maternal organs. For lying phantoms with their feet in the direction of the hypocenter, fetal organ doses from bomb source photon spectra were underestimated by the DS02 system by factors as low as 0.77, while maternal organ doses were overestimated by up to a factor of 1.38. Organs doses from neutron contributions to the radiation fields exhibited an increasing overestimation by the DS02 stylized phantoms as gestational age increased. These discrepancies are most evident in fetal organs that are more posterior within the mother's womb, such as the fetal brain. Further analysis revealed that comparison of these postures to the original standing posture indicate significant dose differences for both maternal and fetal organ doses depending on the type of irradiation. Results from this study highlight the degree to which the existing DS02 system can differ from organ dosimetry based upon 3D radiation transport simulations using more anatomically realistic models of those survivors exposed during pregnancy.

Intra-brain vascular models within the ICRP mesh-type adult reference phantoms for applications to internal dosimetry.

Objective. Phantoms of the International Commission on Radiological Protection provide a framework for standardized dosimetry. The modeling of internal blood vessels-essential to tracking circulating blood cells exposed during external beam radiotherapy and to account for radiopharmaceutical decays while still in blood circulation-is, however, limited to the major inter-organ arteries and veins. Intra-organ blood is accounted for only through the assignment of a homogeneous mixture of parenchyma and blood [single-region (SR) organs]. Our goal was to develop explicit dual-region (DR) models of intra-organ blood vasculature of the adult male brain (AMB) and adult female brain (AFB).Approach. A total of 4000 vessels were created amongst 26 vascular trees. The AMB and AFB models were then tetrahedralized for coupling to the PHITS radiation transport code. Absorbed fractions were computed for monoenergetic alpha particles, electrons, positrons, and photons for both decay sites within the blood vessels and for tissues outside these vessels. RadionuclideS-values were computed for 22 and 10 radionuclides commonly employed in radiopharmaceutical therapy and nuclear medicine diagnostic imaging, respectively.Main results. For radionuclide decays, values ofS(brain tissue ← brain blood) assessed in the traditional manner (SR) were higher than those computed using our DR models by factors of 1.92, 1.49, and 1.57 for therapeutic alpha-emitters, beta-emitters, and Auger electron-emitters, respectively in the AFB and by factors of 1.65, 1.37, and 1.42 for these same radionuclide categories in the AMB. Corresponding ratios of SR and DR values ofS(brain tissue ← brain blood) were 1.34 (AFB) and 1.26 (AMB) for four SPECT radionuclides, and were 1.32 (AFB) and 1.24 (AMB) for six common PET radionuclides.Significance. The methodology employed in this study can be explored in other organs of the body for proper accounting of blood self-dose for that fraction of the radiopharmaceutical still in general circulation.

Systems biology as a framework to understand the physiological and endocrine bases of behavior and its evolution-From concepts to a case study in birds.

Organismal behavior, with its tremendous complexity and diversity, is generated by numerous physiological systems acting in coordination. Understanding how these systems evolve to support differences in behavior within and among species is a longstanding goal in biology that has captured the imagination of researchers who work on a multitude of taxa, including humans. Of particular importance are the physiological determinants of behavioral evolution, which are sometimes overlooked because we lack a robust conceptual framework to study mechanisms underlying adaptation and diversification of behavior. Here, we discuss a framework for such an analysis that applies a "systems view" to our understanding of behavioral control. This approach involves linking separate models that consider behavior and physiology as their own networks into a singular vertically integrated behavioral control system. In doing so, hormones commonly stand out as the links, or edges, among nodes within this system. To ground our discussion, we focus on studies of manakins (Pipridae), a family of Neotropical birds. These species have numerous physiological and endocrine specializations that support their elaborate reproductive displays. As a result, manakins provide a useful example to help imagine and visualize the way systems concepts can inform our appreciation of behavioral evolution. In particular, manakins help clarify how connectedness among physiological systems-which is maintained through endocrine signaling-potentiate and/or constrain the evolution of complex behavior to yield behavioral differences across taxa. Ultimately, we hope this review will continue to stimulate thought, discussion, and the emergence of research focused on integrated phenotypes in behavioral ecology and endocrinology.

Predicting Severity of Radiation Induced Lymphopenia in Individual Proton Therapy Patients for Varying Dose Rate and Fractionation Using Dynamic 4-Dimensional Blood Flow Simulations.

PURPOSE: Radiation-induced lymphopenia has gained attention recently as the result of its correlation with survival in a range of indications, particularly when combining radiation therapy (RT) with immunotherapy. The purpose of this study is to use a dynamic blood circulation model combined with observed lymphocyte depletion in patients to derive the in vivo radiosensitivity of circulating lymphocytes and study the effect of RT delivery parameters. METHODS AND MATERIALS: We assembled a cohort of 17 patients with hepatocellular carcinoma treated with proton RT alone in 15 fractions (fx) using conventional dose rates (beam-on time [BOT], 120 seconds) for whom weekly absolute lymphocyte counts (ALCs) during RT and follow-up were available. We used HEDOS, a time-dependent, whole-body, blood flow computational framework, in combination with explicit liver blood flow modeling, to calculate the dose volume histograms for circulating lymphocytes for changing BOTs (1 second-300 seconds) and fractionations (5 fx, 15 fx). From this, we used the linear cell survival model and an exponential model to determine patient-specific lymphocyte radiation sensitivity, α, and recovery, σ, respectively. RESULTS: The in vivo-derived patient-specific α had a median of 0.65 Gy-1 (range, 0.30-1.38). Decreasing BOT to 1 second led to an increased average end-of-treatment ALC of 27.5%, increasing to 60.3% when combined with the 5-fx regimen. Decreasing to 5 fx at the conventional dose rate led to an increase of 17.0% on average. The benefit of both increasing dose rate and reducing the number of fractions was patient specificࣧpatients with highly sensitive lymphocytes benefited most from decreasing BOT, whereas patients with slow lymphocyte recovery benefited most from the shorter fractionation regimen. CONCLUSIONS: We observed that increasing dose rate at the same fractionation reduced ALC depletion more significantly than reducing the number of fractions. High-dose-rates led to an increased sparing of lymphocytes when shortening the fractionation regimen, particularly for patients with radiosensitive lymphocytes at elevated risk.

A mesh-based model of liver vasculature: implications for improved radiation dosimetry to liver parenchyma for radiopharmaceuticals.

PURPOSE: To develop a model of the internal vasculature of the adult liver and demonstrate its application to the differentiation of radiopharmaceutical decay sites within liver parenchyma from those within organ blood. METHOD: Computer-generated models of hepatic arterial (HA), hepatic venous (HV), and hepatic portal venous (HPV) vascular trees were algorithmically created within individual lobes of the ICRP adult female and male livers (AFL/AML). For each iteration of the algorithm, pressure, blood flow, and vessel radii within each tree were updated as each new vessel was created and connected to a viable bifurcation site. The vascular networks created inside the AFL/AML were then tetrahedralized for coupling to the PHITS radiation transport code. Specific absorbed fractions (SAF) were computed for monoenergetic alpha particles, electrons, positrons, and photons. Dual-region liver models of the AFL/AML were proposed, and particle-specific SAF values were computed assuming radionuclide decays in blood within two locations: (1) sites within explicitly modeled hepatic vessels, and (2) sites within the hepatic blood pool residing outside these vessels to include the capillaries and blood sinuses. S values for 22 and 10 radionuclides commonly used in radiopharmaceutical therapy and imaging, respectively, were computed using the dual-region liver models and compared to those obtained in the existing single-region liver model. RESULTS: Liver models with virtual vasculatures of ~ 6000 non-intersecting straight cylinders representing the HA, HPV, and HV circulations were created for the ICRP reference. For alpha emitters and for beta and auger-electron emitters, S values using the single-region models were approximately 11% (AML) to 14% (AFL) and 11% (AML) to 13% (AFL) higher than the S values obtained using the dual-region models, respectively. CONCLUSIONS: The methodology employed in this study has shown improvements in organ parenchymal dosimetry through explicit consideration of blood self-dose for alpha particles (all energies) and for electrons at energies below ~ 100 keV.

A dynamic blood flow model to compute absorbed dose to circulating blood and lymphocytes in liver external beam radiotherapy.

We have developed a novel 4D dynamic liver blood flow model, capable of accurate dose estimation to circulating blood cells during liver-directed external beam radiotherapy, accounting for blood recirculation and radiation delivery time structure. Adult male and adult female liver computational phantoms with detailed vascular trees were developed to include the hepatic arterial, hepatic portal venous, and hepatic venous trees. A discrete time Markov Chain approach was applied to determine the spatiotemporal distribution of 105blood particles (BP) in the human body based on reference values for cardiac output and organ blood volumes. For BPs entering the liver, an explicit Monte Carlo simulation was implemented to track their propagation along ∼2000 distinct vascular pathways through the liver. The model tracks accumulated absorbed dose from time-dependent radiation fields with a 0.1 s time resolution. The computational model was then evaluated for 3 male and 3 female patients receiving photon (VMAT and IMRT) and proton (passive SOBP and active PBS) treatments. The dosimetric impact of treatment modality, delivery time, and fractionation on circulating blood cells was investigated and quantified using the mean dose (µdose,b),V>0Gy,V>0.125Gy,andD2%. Average reductions inµdose,b,V>0Gy,V>0.125GyandD2%of 45%, 6%, 53%, 19% respectively, were observed for proton treatments as compared to photon treatments. Our simulation also showed thatV>0Gy,V>0.125Gy, andD2%were highly sensitive to the beam-on time. BothV>0GyandV>0.125Gyincreased with beam-on time, whereasD2%decreased with increasing beam-on time, demonstrating the tradeoff between low dose to a large fraction of blood cells and high dose to a small fraction of blood cells. Consequently, proton treatments are not necessarily advantageous in terms of dose to the blood simply based on integral dose considerations. Instead, both integral dose and beam-on time can substantially impact relevant dosimetric indices.

Evaluation of Platelet Rich Fibrin Obtained Using Different Centrifugation Parameters as a Tool for Regenerative Medicine.

BACKGROUND: Platelet-rich fibrin (PRF) is a biomaterial widely used in the field of regenerative medicine. The purpose of this work was to analyze the structure and biomolecular characteristics of PRF through nine centrifugation parameters (CP) for its preparation, using a pool of blood samples of five volunteers. METHODS: The PRF obtained was analyzed by morphological and histological characteristics, as well as electronic and atomic force microscopy and growth factors determinations. RESULTS: A longer time of centrifugation showed taller clots and denser mesh fibrin in comparison with a short time (p < 0.05). The protocols with higher speed of centrifugation showed higher levels of PDGF-BB and VEGF. Higher levels of TGFß1 were found in protocols with a shorter centrifuge time. The mean platelet count (916.05 ± 23.73 cells x 103 cells x cm3) and its roughness (Ra) (616.5 ± 45.2 nm) did not show significant differences between different CP (p > 0.05). A significant correlation between fibrin density and levels of PDGF (r = 0.57) and VEGF (r = 0.52) was found. Additionally, the size of the clot had a significant correlation (r = -0.47) with TGFß1 levels. CONCLUSIONS: Different centrifugation parameters to obtain PRF have been reported. These results indicate that changes in the conditions to obtain PRF have a significant impact on their fibrin structure, cellular distribution, and biomolecular content, which can be decisive for its choice in the different clinical applications to be used. It is necessary to use a standardized centrifuge and protocol to guarantee high-quality PRF and clinical outcomes with less variability.

Integrative Studies of Sexual Selection in Manakins, a Clade of Charismatic Tropical Birds.

The neotropical manakins (family Pipridae) provide a great opportunity for integrative studies of sexual selection as nearly all of the 51 species are lek-breeding, an extreme form of polygyny, and highly sexually dimorphic both in appearance and behavior. Male courtship displays are often elaborate and include auditory cues, both vocal and mechanical, as well as visual elements. In addition, the displays are often extremely rapid, highly acrobatic, and, in some species, multiple males perform coordinated displays that form the basis of long-term coalitions. Male manakins also exhibit unique neuroendocrine, physiological, and anatomical adaptations to support the performance of these complex displays and the maintenance of their intricate social systems. The Manakin Genomics Research Coordination Network (Manakin RCN, https://www.manakinsrcn.org) has brought together researchers (many in this symposium and this issue) from across disciplines to address the implications of sexual selection on evolution, ecology, behavior, and physiology in manakins. The objective of this paper is to present some of the most pertinent and integrative manakin research as well as introducing the papers presented in this issue. The results discussed at the manakin symposium, part of the 2021 Society for Integrative and Comparative Biology Conference, highlight the remarkable genomic, behavioral, and physiological adaptations as well as the evolutionary causes and consequences of strong sexual selection pressures that are evident in manakins.

Treatment of Miller I Mandibular Gingival Recessions Using PRF vs. Connective Graft.

Gingival recession (GR) can cause aesthetic and functional problems. Using connective tissue graft (CTG) and coronally advanced flap (CAF) is considered the technique of choice for treating GR. Considering the morbidity resulting from taking CTG, different alternative biomaterials have been described, including plasma-rich fibrin (PRF) membrane. Studies in lower teeth are few because of the complexity of the factors that can influence obtaining less predictable outcomes. Objective. To compare between CAF + PRF and CAF + CTG in the treatment of lower teeth Miller I gingival recession. Methodology. Split-mouth included 26 isolated GR (13 in each side of the mouth). The left side was treated with CAF + PRF and the right side with CAF + CTG. Clinical variables, probing depth (PD), GR, keratinized tissue (KT), vestibular soft tissue thickness (VSTT), and teeth sensitivity (TS), were assessed at the baseline. GR, KT, VSTT, extraoral inflammation (EI), and patient discomfort (PaD) were assessed at 45 days. Results. Statistically greater VSTT at 45 days was obtained using CAF + CTG (p < 0.05). Less EI and PaD were obtained using CAF + PRF (p < 0.05). No change was observed in GR, KT, and TS values in the intergroup or intragroup comparisons. Conclusion. Even with the limitations of this study, using PRF and CTG in lower teeth demonstrated an improvement in terms of root coverage, although it was without a total percentage of coverage. Regarding the VSTT, better results were obtained using the CTG + CAF, suggesting eventually long-term stable clinical results. We suggest a combined technique for future investigations.

Low-Level Laser Irradiation Promotes Proliferation and Differentiation on Apical Papilla Stem Cells.

Introduction: Low-level laser therapy (LLLT) has been reported to improve cell proliferation and differentiation. The stem cells derived from dental apical papilla (SCAPs) are a promising therapy because they are easily obtained from immature human teeth. The effect of LLLT over SCAPs is still unknown. This study aimed to evaluate the proliferation and osteogenic potential of the SCAPs stimulated with LLLT. Methods: SCAPs were isolated from the third molars of a healthy donor and characterized according to the minimum established criteria. SCAPs were cultured for 24 hours before being exposed to LLLT. Cells were exposed to different doses, energy, and wavelengths for selecting the irradiation parameters. SCAPs proliferation was evaluated with the MTT assay at 24 hours and 7-day post-laser exposure. VEGF and TGFß2 expression were assessed with a specific enzyme-linked immunosorbent assay (ELISA). The osteogenic differentiation potential was analyzed with alizarin red staining, and the nodule quantification was performed by the relative optical density (ROD) analysis using ImageJ software. Results: The cells isolated from the apical papilla showed phenotype and stem cell properties. SCAPs irradiated with one dose at 6 J/m2 and 650 nm exhibited significantly higher proliferation (P>0.05) than the controls nonirradiated. LLLT stimulated SCAPs' expression of factors VEGF and TGFß2. Also, SCAPs irradiated showed higher osteogenic activity (P<0.05). Conclusion: LLLT promotes proliferation, osteogenic differentiation, and VEGF and TGFß2 expression on SCAPs. LLLT is a practical approach for the preconditioning of SCAPs in vitro for future regenerative therapies. More studies are needed to determine the underlying molecular processes that determine the mechanism of the LLLT.

Dosimetric dependence of ocular structures on eye size and shape for external radiation fields of electrons, photons, and neutrons.

The dosimetric dependence of ocular structures on eye size and shape was investigated within the standard ICRP Publication 116 irradiation geometries. A realistic transport geometry was constructed by inserting a scalable and deformable stylised eye model developed in our previous study within the head of the ICRP Publication 110 adult male reference computational phantom. Beam irradiations of external electrons, photons, and neutrons on this phantom were simulated using the Monte Carlo radiation transport code PHITS in the geometries of AP, RLAT, PA and ROT. Absorbed doses in ocular structures such as ciliary body, retina, and optic nerves were computed as well as that in lens. A clear dosimetric dependence of ocular structures on eye size and shape was observed for external electrons while only a small dependence was seen for external photons and neutrons. Difference of the tendency was attributed to their depth-dose distributions where spread dose distributions were created by photons and neutrons while more concentrated distributions were created by external electrons.

Leucemia linfoide aguda y mal de Pott: respuesta paradójica al tratamiento ANTITBC / Acute lymphoid leukemia and pott disease: parodixical response to anti-tb treatment

Hombre de 58 años con diagnóstico de leucemia linfoide aguda llevado a trasplante de progenitores de sangre periférica de donante intrafamiliar. Requirió manejo inmunosupresor por presencia de enfermedad injerto contra huésped aguda y crónica. Consultó por dolor lumbar severo y en los exámenes se encontraron lesiones compatibles con espondilodiscitis L4-L5 y colecciones paravertebrales. Con sospecha de tuberculosis se inició tratamiento empírico, la evolución clínica inicial fue tórpida por persistencia de síntomas y compromiso neurológico progresivo, por lo cual se sospechó presencia de micobacterias atípicas vs resistentes. Se logró aislamiento de Mycobacterium tuberculosis susceptible a la terapia instaurada. Se continuó esquema de tratamiento TBC con evolución clínica a la mejoría. Se interpretó como reacción paradójica a la terapia, pero con presencia de lesión renal en la que se confirmó recaída de la enfermedad hematológica...

We report the case of a 58 year-old male patient diagnosed with acute lymphoid leukemia who received a peripheral blood stem cell transplant from a family member. He required immunosuppressive management for developing acute and chronic graft-versus-host disease. He presented with severe back pain. Imaging showed spondylodiscitis L4/L5 and paravertebral fluid collections. Empirical anti-TB therapy was instituted for suspicion of tuberculosis. The initial phase was torpid due to persistent symptoms and progressive neurologic compromise, thus, the presence of atypical vs resistant mycobacteria was suspected. Initiated-therapy-susceptible Mycobacterium tuberculosis was isolated. The anti-TB therapy regimen was continued with improvement in his clinical state. It was interpreted as a paradoxical response to therapy, associated with the presence of a renal lesion in which a relapse of the hematologic condition was confirmed...

Descripción clínica y tratamiento de los pacientes con síndrome coronario agudo / Clinical description and treatment of patients with acute coronary syndrome

Antecedentes: el síndrome coronario agudo es una emergencia clínica que se manifiesta principalmente por dolor torácico. Su diagnóstico representa un desafío clínico y su reconocimiento temprano es fundamental para el tratamiento. Objetivo: describir las características clínicas, identificar abordajes terapéuticos y conocer los desenlaces de los pacientes con diagnóstico definitivo de síndrome coronario agudo hospitalizados por el servicio de medicina interna y cardiología entre el 1° de enero de 2009 hasta 31 de diciembre de 2010 en el Hospital San José. Métodos: se realizó una descripción de una cohorte de pacientes con diagnóstico de síndrome coronario agudo (infarto miocárdico con y sin elevación del segmento ST y angina inestable). Se analizaron variables demográficas, características clínicas, tratamiento y desenlaces a los cuales se calcularon promedio, desviación estándar y proporciones según la naturaleza de las mismas. Resultados: se reportan 133 pacientes. El 63% correspondió a hombres, el promedio de edad fue de 64.8 años. La frecuencia de eventos fue 45.9% IMEST, 39% IMSEST y 15.1% anginas inestables. El 96.2% de los pacientes consultó por dolor torácico, 50.7% presentaron dolor en las primeras seis horas de evolución. El 93% recibió betabloqueador, 88% IECA, 87% clopidogrel y 97% ASA. Se trombolizó al 82% de los pacientes en ventana. La mortalidad intrahospitalaria fue del 8.7%. Conclusiones: en la población estudiada predominó el síndrome coronario agudo sin elevación del segmento ST. La mayoría de pacientes consultaron por dolor torácico retroesternal, en las primeras horas de inicio. El porcentaje de uso de los medicamentos fue adecuado. La reperfusión inmediata en pacientes con IMEST fue alta, sin embargo aún tenemos pacientes que no se benefician de esta terapia y el uso de angioplastias primarias fue muy bajo. (Acta Med Colomb 2014; 39: 124-130).

Background: acute coronary syndrome is a medical emergency that is manifested mainly by chest pain. The diagnosis is a clinical challenge and its early recognition is essential for treatment. Objective: to describe the clinical characteristics, identify therapeutic approaches and recognize the outcomes of patients with a final diagnosis of acute coronary syndrome hospitalized in Internal Medicine and Cardiology services between January 1, 2009 until December 31, 2010 at the Hospital San José. Methods: description of a cohort of patients diagnosed with acute coronary syndrome (myocardial infarction with and without ST segment elevation and unstable angina) was performed. Demographic variables, clinical characteristics, treatment and outcomes were analyzed and average, standard deviation and proportions were calculated according to their the nature. Results: 133 patients were reported. 63% were men, the mean age was 64.8 years. The event rate was 45.9% STEMI, 39% NSTEMI and unstable angina 15.1%. 96.2% of patients consulted for chest pain, 50.7% had pain in the first six hours of evolution. 93% received beta-blockers, 88% ACE inhibitors, 87% clopidogrel and 97% ASA. 82% of patients in window underwent thrombolysis. The hospital mortality was 8.7%. Conclusions: in the studied population acute coronary syndrome without ST segment elevation predominated. Most patients consulted by retrosternal chest pain in the early hours of onset. The percentage of drug use was appropriate. Immediate reperfusion in STEMI patients was high; however we still have patients who do not benefit from this therapy and the use of primary angioplasty was very low. (Acta Med Colomb 2014; 39: 124-130).