Alejandro Zárate C
Pontifical Catholic University of Chile
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Featured researches published by Alejandro Zárate C.
Revista Medica De Chile | 2003
Francisco López K.; Gonzalo Soto D.; Grace Tapia N; Katty Schnettler I; Alejandro Zárate C; Rodolfo Avendaño H.; George Pinedo M; Gustavo Pérez B.; Luis Ibáñez A.
Background: Elective surgery in diverticular disease (DD) consists classically in performing an open sigmoidectomy. Laparoscopic surgery of the colon can have results that are comparable to those of open surgery. Aim: To compare the results of laparoscopic and conventional surgery for DD. Materials and Methods: Retrospective review of preoperative, operative and postoperative variables of patients operated by laparoscopic surgery between the years 2000 and 2002. These results were compared with those of patients treated with conventional surgery in the same period. Results: Thirty nine patients, mean age 59 years old, were operated via laparotomy and 18 patients, mean age 47 years old, were treated with laparoscopic surgery. Both groups were comparable in gender, amount of previous laparotomies, type of surgery performed and American Society of Anestesiologists classification. The operative time was significantly higher in the laparoscopic surgery group (230 v/s 130 min), but the opioid requirements, stay in an intensive surgical care ward, postoperative ileus and hospital stay were significantly shorter in the laparoscopic group. Eleven percent of the patients included in the laparoscopic group and 31% of the patients treated with operative surgery had complications (p=0.07). The length of the excised colon, the degree of inflammation and treatment costs were comparable. Conclusions: Laparoscopic surgery in DD is feasible, safe, requires less analgesia and allows a faster recovery of post-operative ileus and a lower hospital stay (Rev Med Chile 2003; 131: 719-26)
Revista Chilena De Cirugia | 2007
Francisco López-Köstner; Alejandro Zárate C; George Pinedo M; María E Molina P; Udo Kronberg; Trinidad Sepúlveda S; Priscilla Valdebenito B; Ivette Arraigada J
Introduccion: La endosonografia anorrectal (EAR) es una alternativa diagnostica en las patologias anorrectales. Objetivo: Analizar las principales indicaciones y resultados de la EAR. Material y metodo: Estudio prospectivo, descriptivo desarrollado entre Noviembre 1999 hasta Septiembre 2004. Se correlaciono el informe de la EAR con los hallazgos quirurgicos y resultados de biopsias. Analisis mediante concordancia. Resultados: En el periodo mencionado se realizaron 1000 EAR, (62% mujeres, edad promedio 55 anos). Las indicaciones fueron etapificacion y seguimiento de cancer rectal (CR) en 279 pacientes, otros tumores 119, incontinencia fecal (IF) en 336, fistulas perianales en 137, dolor anal (DA) en 73, y otras indicaciones en 56 pacientes. En la etapificacion del CR la concordancia general para la profundidad tumoral y compromiso linfonodal fue 81,6% y 67,8%, respectivamente. En el estudio de IF, la EAR resulto normal en el 17%, se informo interrupcion de ambos esfinteres en 16% de los pacientes, interrupcion del esfinter anal externo en el 65% y del esfinter anal interno aislado en el 2%. En 30 pacientes operados por IF en nuestra institucion, hubo 100% de concordancia entre hallazgos endosonograficos e intraoperatorios. En el estudio por fistulas perianales, 10,2% normales, 64,2% confirmaron la fistula, 13,1% evidencio una coleccion y en el 12,5% otros diagnosticos. En el estudio por DA, 36 EAR fueron normales y en 37 se evidencio alguna alteracion (50,7%). Conclusion: Las indicaciones mas frecuentes fueron el estudio de pacientes con incontinencia fecal y etapificacion del cancer de recto. Existe adecuada concordancia entre hallazgos endosonograficos y quirurgicos
Revista Medica De Chile | 2008
Alejandro Zárate C; Álvaro Zúñiga D; George Pinedo M; Francisco López K.; María E Molina P; Paola Viviani G
All patients subjectedto an IPAA, from 1984 to 2006 were identified from a prospectively constructed inflammatory boweldisease database. Surgical variables, postoperative complications and functional evaluation, usingOresland score were analyzed. Chi square, Fischer exact test, T Student, Mann Whitney and binarylogistic regression were included in the statistical analysis.
Revista Chilena De Cirugia | 2008
Alejandro Zárate C; Francisco López-Köstner; Carolina Loureiro P; George Pinedo M; María E Molina P; Udo Kronberg; Paola Viviani G
Resumen es: Objetivo: Comparar resultados y complicaciones inmediatas al realizar una sigmoidectomia laparoscopica (SL) versus abierta (SA) en pacientes con cancer d...
Revista Chilena De Cirugia | 2012
Francisco López-Köstner; Katya Carrillo G.; Alejandro Zárate C; Andrés O'Brien S; David Ladrón De Guevara H.
Rectal cancer: diagnosis, study and staging Rectal cancer is defi ned as a tumour located between the anal verge and 15 cm within anal verge. In rectal cancer, a precise preoperative staging allows to categorize patients for different available treatments, as well as decide the best surgical treatment. Preoperative staging is performed by several radiological tech- niques. Currently available procedures are endorectal ultrasound (EUS), computed tomography (CT) mag- netic resonance (MRI), positron emission tomography-computed tomography (PET/CT) and intraoperative ultrasound. EUS is a procedure performed by the colorrectal surgeon that allows the evaluation of the depth of tumour invasion as well as lymph node status; nevertheless its main shortcoming is the inability to assess mesorectal fascia involvement. Nowadays, MRI is the best method to assess mesorectal fascia involvement in addition to tumour invasion and lymph nodes involved. CT is a widely available procedure, and its main use is evaluation of distant metastases, with lower accuracy to assess tumour invasion and lymph node status. PET/CT is currently gaining importance, however its role in preoperative staging its not widely accepted. IOUS allows evaluation of liver metastases during surgery, and therefore determines management and prog- nosis. Consequently, is necessary for surgeons to maintain an up-to-date knowledge of current methods, its advantages and limitations.
Revista Chilena De Cirugia | 2008
Álvaro Zúñiga D; Alejandro Zárate C; Demian Fullerton M.; Ignacio Duarte G; Manuel Alvarez L; Carlos Quintana V
Introduccion: La proctocolectomia con reservorio ileal y anastomosis reservorio anal, (RIARA) es actualmente el procedimiento de eleccion en el tratamiento quirurgico electivo de la colitis ulcerosa (CU). La colectomia total y anastomosis ileorrectal (AIR), esta indicada en un seleccionado grupo de pacientes. Algunos pacientes sometidos a estas operaciones por aparente CU pueden evolucionar como una enfermedad de Crohn (EC). Objetivo: Comunicar el curso y pronostico de pacientes que evolucionaron como EC luego de un tratamiento quirurgico por una aparente CU. Materiales y metodos: Se identificaron a los pacientes que tuviesen tratamiento quirurgico por CU, en el periodo 1978 al 2003. Se seleccionaron a los pacientes en los cuales en su evolucion se cambio el diagnostico a EC. En ellos se analizaron las variables quirurgicas y su evolucion posterior. Resultados: En el periodo mencionado se operaron 114 pacientes por CU. En 9 pacientes (8%) el diagnostico cambio a EC, basado principalmente en la evolucion clinica alejada y/o por estudio histologico: 3 de 20 (15%) despues de una colectomia total con AIR y 6 de 84 (7%) despues de una proctocolectomia con RIARA. Las localizaciones mas frecuentes de las manifestaciones de la EC fueron el canal anal y perine. El tratamiento incluyo procedimientos quirurgicos y tratamiento medico con antiinflamatorios y/o inmunomoduladores. Dos pacientes con una colectomia con AIR necesitaron una proctectomia e ileostomia. Se extirpo el reservorio en 1 de 6 pacientes con RIARA. En resumen, una minoria de pacientes sometidos a tratamiento quirurgico con el diagnostico de CU evoluciona posteriormente como una EC. El tratamiento combinado medico quirurgico contribuye a una baja incidencia de perdida del reservorio ileal
Revista Chilena De Cirugia | 2008
Alejandro Zárate C; George Pinedo M; María E Molina P; Carolina Loureiro P; Carlos Quintana V; Álvaro Zúñiga D
Introduccion: Aproximadamente el 50% de los pacientes con Enfermedad de Crohn (EC) necesitaran de un tratamiento quirurgico en algun momento de su evolucion. La reseccion ileocecal (RIC) es una de las operaciones mas frecuentes en pacientes con EC. Objetivo: Identificar las indicaciones quirurgicas y determinar el porcentaje de recurrencia de la enfermedad a largo plazo de los pacientes sometidos a RIC por EC. Material y metodo: Se incluyeron todos los pacientes sometidos consecutivamente a RIC entre Enero 1970 y Diciembre 2006 y se analizaron caracteristicas demograficas, indicacion operatoria, variables intraoperatorias, complicaciones y, en el seguimiento, la recurrencia de la enfermedad. Resultados: 28 pacientes fueron operados en el periodo mencionado. 17 mujeres (60,7%), edad promedio del diagnostico de EC: 34,8 anos (i: 14-60) y de la RIC: 43,3 anos (i: 16-68). Seis pacientes habian sido operados previamente por EC (3 sobre el perine y 3 resecciones parciales de intestino, no RIC). Una o mas de las siguientes condiciones contribuyeron a la indicacion quirurgica: Obstruccion intestinal intermitente en 21 pacientes, refractariedad a tratamiento medico en 10, fistula enteral en 2 y hemorragia digestiva baja en 2. Nueve pacientes (32,1%) tuvieron una o mas complicaciones postoperatorias, 3 (10%) de los cuales fueron reintervenidos (2 por filtracion de la anastomosis, uno por hemoperitoneo). La mediana de estadia postoperatoria fue 9 dias. No hubo mortalidad operatoria. En el seguimiento a largo plazo, 3 pacientes desarrollaron Ileo mecanico por bridas. Todos ellos resueltos quirurgicamente. Cuatro pacientes (14%) fueron reintervenidos por recidiva de la EC con tiempo medio desde la RIC de 63 meses. La sobrevida a 5 anos fue de 96%. Conclusion: La RIC por EC, se indica principalmente por obstruccion intestinal debida a estenosis. La estenosis en la recidiva de la enfermedad es baja
Revista Chilena De Cirugia | 2008
Francisco López-Köstner; Alejandro Zárate C
El objetivo de este trabajo es presentar el resultado de la primera proctocolectomia laparoscopica con reservorio ileo-anal, sin ileostomia de proteccion, practicada en el Hospital Clinico de la Pontificia Universidad Catolica de Chile. La operacion se realizo en un paciente de 34 anos con poliposis adenomatosa familiar. El paciente tuvo un cuadro clinico de un mes y medio de evolucion, caracterizado por dolor abdominal y cambio del habito intestinal. El estudio colonoscopico revelo la presencia de multiples polipos en colon (>100 polipos), asi como tambien, compromiso rectal. Dado los hallazgos intraoperatorios se decidio efectuar una proctocolectomia laparoscopica mas un reservorio ileal en J, sin ileostomia de proteccion; la pieza operatoria se extrajo mediante una incision de Pfannenstiel. La cirugia se realizo sin dificultades en un tiempo de 340 minutos. El paciente se realimento con liquidos al 5o dia y se dio de alta al 9o dia postoperatorio, sin complicaciones. No se registraron complicaciones en el seguimiento temprano a 30 dias del alta hospitalaria. Luego de 6 meses desde su operacion, el paciente presenta 4-6 deposiciones diarias, sin urgencia y utiliza loperamida® en forma esporadica
Revista Medica De Chile | 2005
Gonzalo Soto D.; Francisco López-Köstner; Alejandro Zárate C; Fernando Vuletin S; Alejandro Rahmer O.; Francisca León G; Álvaro Zúñiga D
Background: To reduce the mortality associated to Familial Adenomatous Polyposis (FAP), screening of close relatives of patients with the disease is crucial. Aim: To analyze the results of the surgical treatment of patients with FAP, and to evaluate the family screening. Patients and Methods: Clinical records of patients operated in our institution since 1977, were reviewed analyzing surgical and pathological results, and follow up. In their family members, we evaluated and analyzed the performance of screening tests, former surgeries, history of disease-related cancer and mortality, all due to FAP. Results: Between January 1977 and August 2002, 15 patients were operated on. Of these, only 33% consulted on the setting of a familial screening. A proctocolectomy and terminal ileostomy was performed in 27% of patients; 20% had a proctocolectomy and ileal pouch, and 53% underwent a total colectomy with ileo-rectal anastomosis. Morbidity and mortality were 7% and 0%, respectively. Twenty percent had a colorectal cancer. During a median of 68 months follow-up, the disease-related survival was 92%; no cancer of the rectal stump was detected. Of the 122 family members identified, only 33% with clear indication of screening underwent a colonoscopy. Twenty-nine percent had a confirmed FAP and were operated: in 61% of them a colorectal cancer was found, and 91% of these died. Conclusions: The results of the surgical treatment of FAP are satisfactory. Nevertheless, family screening should be improved to reduce the high rates of mortality revealed in the study of other family members (Rev Med Chile 2005; 133: 1043-50).
Revista Chilena De Cirugia | 2015
Alejandro Zárate C; Karin Alvarez; Cynthia Villarroel S; Ana María Wielandt N.; Udo Kronberg; Gabriel Cavada R; Daniela Simian M.; Luis Contreras M; Francisco López-Köstner
Lymphocyte infiltration and microsatellite instability in colorectal cancer patients Background: In colorectal cancer (CRC) patients, lymphocyte infiltration (LI) and microsatellite insta bility (MSI) have been associated with better prognosis. aim: To analyze the association between components of LI (CD3/CD4/CD8/CD45R0/FoxP3) and MSI status with metastatic stages in CRC patients. material and methods: Prospective study of 109 patients diagnosed with CRC. The expression of CD3, CD4, CD8, CD45R0 and FoxP3 markers, was evaluated by immunohistochemical analysis, and tumors were classified into negative, low and intense expression. The MSI was assessed with seven markers amplified by PCR from normal and tumoral DnA. Tumors were grouped in MSS (stable)/MSI-low and MSI-high. Statistical analysis was performed with Fischer’s exact test. results: 29%, 28%, 12% and 86% of tumors exhibits intense expression of CD3+, CD4+, CD8+ and CD45RO+ lymphocytes, respectively. 84% of the tumors presented MSS/ MSI-low and 16% had MSI-high. Tumors that show a high density of T cells (CD3+, CD4+ y CD45R0+) are associated with early stage tumors (I and II) (p = 0.023; p = 0.030 and p = 0.003, respectively). Additionally, there was a significant association between the MSS/MSI-low tumors and a reduced ability to recruit CD8+ cytotoxic T lymphocytes (p = 0.037) and CD3+ (p = 0.064). conclusion: There is an association between high densities of CD3+, CD4+ and CD45RO+ lymphocytes and non-metastatic tumors. In addition, MSS/ MSI-low tumors are associated with a lower recruitment of CD8+ and CD3+ lymphocytes.