Attached right aortic valve leaflet causing ischemia and severe regurgitation: Successful repair with Ozaki technique.

INTRODUCTION: Coronary artery occlusion due to fusion of a leaflet to the sinotubular junction is a rare finding that we should consider in the differential diagnosis of young patients who have aortic regurgitation and angina. PATIENT AND METHOD: We present a young female with severe aortic regurgitation due to right coronary fusion who underwent mini-invasive aortic valve reconstruction. RESULTS: Postoperative evolution was satisfactory. The patient was discharged on the 5th postoperative day and after 3.5 years of follow-up he remains in functional class I, without anticoagulant treatment and with mild aortic regurgitation. COCNCLUSION: The Ozaki technique can be used in patients with aortic regurgitation due to single leaflet dysfunction.

Pulmonary Valve Reconstruction Using Autologous Pericardium: A Promising Technique to Consider.

Pulmonary valve (PV) surgical treatment is uncommon in adults; however, when it is indicated, replacement with a prosthesis is suggested. Nevertheless, mechanical prostheses have an inherent risk of complications derived from anticoagulation and thrombosis, and biologic prostheses do not have adequate long-term durability. In this context, PV reconstruction surgery emerges as an alternative, avoiding anticoagulation and promising good durability. We present our experience with this procedure in 3 patients with severe PV insufficiency and 1 patient with severe PV stenosis.

[Aortic valve reconstruction surgery with Ozaki technique: initials results from a single center]. / Cirugía de reconstrucción de válvula aórtica con técnica de Ozaki: resultados iniciales en un centro de referencia.

Background: Aortic valve (AV) replacement is the gold standard treatment for severe symptomatic AV disease. Recently, AV reconstruction surgery (Ozaki procedure) emerges as a surgical alternative with good results in the medium term. Methods: We retrospectively analyzed 37 patients who underwent AV reconstruction surgery between January 2018 and June 2020 in a national reference center in Lima, Peru. The median age was 62 years, interquartile range (IQR: 42-68). The main indication for surgery was AV stenosis (62.2%), in most cases due to bicuspid valve (19 patients, 51.4%). Twenty-two (59.4%) patients had another pathology with surgical indication associated to AV disease, 8 (21.6%) had dilatation of the ascending aorta with indication for replacement. Results: One in-hospital death occurred (1/38, 2.7%) due to perioperative myocardial infarction. There was a significant reduction in the medians of the peak (70 mmHg, CI 95% = 50.03-79.86 vs. 14 mmHg, CI 95% = 11.93-17.5, p < 0.0001) and mean (45.5 mmHg CI 95% = 30.6-49.68 vs. 7 mmHg, CI 95% = 5.93-9.6, p < 0.0001) AV gradients when we compared baseline characteristics with first 30-days results. In an average of 19 (± 8.9) months of follow-up, survival, reoperation-free survival for valve dysfunction, and survival free of AV insufficiency ≥ II were 97.3%, 100% and 91.9%, respectively. Significant reduction in the medians of the peak and mean AV gradients was maintained. Conclusions: AV reconstruction surgery showed optimal results in term of mortality, reoperation-free survival, and hemodynamic characteristics of the neo-AV.

Introducción: El reemplazo de la válvula aórtica es el tratamiento de elección para la valvulopatía aórtica severa sintomática. Recientemente, la cirugía de reconstrucción valvular aórtica (procedimiento de Ozaki) emerge como una alternativa quirúrgica con buenos resultados a mediano plazo. Métodos: Analizamos retrospectivamente 37 pacientes intervenidos de reconstrucción de válvula aórtica entre enero de 2018 y junio de 2020 en un centro de referencia nacional en Lima, Perú. La mediana de edad fue de 62 años (rango intercuartílico: 42-68). La estenosis de la válvula fue la principal indicación de cirugía (62.2%), en la mayoría de los casos por válvula bicúspide (19 pacientes, 51.4%). 22 (59.4%) pacientes presentaban otra patología con indicación de cirugía, 8 (21.6%) presentaban dilatación de la aorta ascendente con indicación de reemplazo. Resultados: La mortalidad intrahospitalaria fue de 1/38, 2.7%, por infarto de miocardio perioperatorio. Hubo una reducción significativa en las medianas del gradiente máximo (70 mmHg, IC 95% = 50.03-79.86 vs. 14 mmHg, IC 95% = 11.93-17.5, p < 0.0001) y gradiente medio (45.5 mmHg IC 95% = 30.6-49.68 vs. 7 mmHg, IC 95% = 5.93-9.6, p < 0.0001) de la válvula aórtica cuando comparamos las características basales con los resultados de los primeros 30 días. En una media de 19 (± 8.9) meses de seguimiento la sobrevida fue del 97.3%; la sobrevida libre de reoperación por disfunción valvular, 100% y la sobrevida libre de insuficiencia aórtica ≥ II, 91.9%, respectivamente. Se mantuvo una reducción significativa en las medianas de los gradientes máximo y medio de la válvula aórtica. Conclusiones: La cirugía de reconstrucción de válvula aórtica con pericardio autólogo mostró resultados óptimos en términos de mortalidad, supervivencia libre de reoperación y características hemodinámicas de la neo-válvula.

A new surgical technique for left atrial reduction in giant left atrium.

Objective: The study objective was to evaluate the safety and clinical and echocardiographic outcomes of a new surgical technique in adult patients diagnosed with a giant left atrium. Methods: We analyzed a cohort of patients who underwent left atrium reduction surgery between January 2016 and June 2020 performed by a specialized surgical team in 2 national reference centers in Lima, Peru. We assessed the major adverse valvular-related events and the New York Heart Association functional class as primary clinical outcomes. Also, our primary echocardiographic endings were the diameter, area, and volume of the left atrium. We assessed these variables at 3 time periods: baseline (t0), perioperative period (t1), and extended follow-up (t2: 12 ± 3.4 months). We carried out descriptive and bivariate exploratory statistical analysis for dependent measures. Results: We included 17 patients, 70.6% of whom were women. Rheumatic mitral valve disease (76.5%) was the main etiology. We performed 14 (82.4%) mitral valve replacements and 3 repairs. Major adverse valvular-related events occurred in 1 patient (5.9%) (hemorrhagic stroke) at t1. A significant reduction in the size of the left atrium was observed: diameter (77 mm vs 48 mm, P < .001), area (75 cm2 vs 31 cm2, P < .001), and volume (332 cm3 vs 90 cm3, P < .001). Compared with t0 and t1, these echocardiographic findings remained without significant changes during t2. Conclusions: Our surgical left atrium reduction technique was associated with improved clinical functionality and reduced left atrium measures in patients with a giant left atrium undergoing mitral valve surgery.

Mast cell degranulation mediates compound 48/80-induced hyperalgesia in mice.

Mast cells mediate allergies, hypersensitivities, host defense, and venom neutralization. An area of recent interest is the contribution of mast cells to inflammatory pain. Here we found that specific, local activation of mast cells produced plantar hyperalgesia in mice. Basic secretagogue compound 48/80 induced plantar mast cell degranulation accompanied by thermal hyperalgesia, tissue edema, and neutrophil influx in the hindpaws of ND4 Swiss mice. Blocking mast cell degranulation, neutrophil extravasation, and histamine signaling abrogated these responses. Compound 48/80 also produced edema, pain, and neutrophil influx in WT C57BL/6 but not in genetically mast cell-deficient C57BL/6-Kit(W-sh)(/)(W-sh) mice. These responses were restored following plantar reconstitution with bone marrow-derived cultured mast cells.

[Prevalence of coronary anomalies detected by computed tomography at the Instituto Nacional Cardiovascular- INCOR]. / Prevalencia de anomalías coronarias detectadas por tomografía computarizada en el Instituto Nacional Cardiovascular - INCOR.

Objective: : To determine the prevalence of coronary anomalies (CA) in patients evaluated by 64-detector computed tomography (CT) at the Instituto Nacional Cardiovascular in Peru between 2016 and 2020. Materials and methods: Retrospective observational study, coronary artery CT scans of 1486 patients were performed on a 64-detector row CT scanner and reviewed in search for coronary anomalies. Results: The prevalence of CA detected by CT was 4.71% (70 cases) of which 64.3% were male. Abnormalities of origin were the most frequent, of which the origin of a coronary artery from the opposite coronary sinus was the most common (48.6%), with the right coronary being the main anomalous artery (31%), and the main path was interarterial (31%). Anomalous origin of the left main coronary from the pulmonary artery was found in 5 patients. Among the anomalies of the intrinsic coronary arterial anatomy the most frequent was the double left anterior descending artery (10%). Coronary fistulas accounted for 11.4% of cases. Conclusions: The prevalence of CA detected by 64-detector CT in a Peruvian institute was 4.71%. The most frequent coronary anomaly was the origin of the right coronary artery from the left coronary sinus with interarterial trajectory.

[Prediction of significant coronary lesions by SPECT myocardial perfusion. Results from a national reference hospital in Lima-Peru]. / Predicción de lesiones coronarias significativas mediante perfusión miocárdica con SPECT. Resultados de un centro de referencia nacional en Lima-Perú.

Objective: To determine the discriminative capacity of myocardial perfusion with single photon emission tomography (SPECT) to predict coronary obstructions by coronary angiography. To determine mortality and major cardiovascular events at follow-up. Materials and methods: . Retrospective observational study with clinical follow-up in patients undergoing SPECT and then coronary angiography. We excluded patients with myocardial infarction and percutaneous and/or surgical revascularization in the previous 6 months. Results: 105 cases were included in the study. The most commonly used SPECT protocol was pharmacological (70%). Patients with perfusion defect ≥10% of total ventricular mass (TVM) had significant coronary lesions (SCL) in 88% of cases (sensitivity 87.5% and specificity 83%). On the other hand, having ischemia ≥10% of the TVM was associated with 80% SCL (sensitivity: 72%, specificity: 65%). Clinical follow-up at 48 months evidenced that a perfusion defect ≥ 10% was predictive of major cardiovascular events (MACE) in both univariate (HR=5.3; 95%CI 1.2 - 22.2; p=0.022) and multivariate (HR= 6.1; 95%CI 1.3 - 26.9; p= 0.017) analyses. Conclusions: . Having a perfusion defect ≥10% of the MVT in the SPECT study predicted with high probability and sensitivity the existence of SCL (>80%); moreover, this group had higher MACE at follow-up.

[Coronary artery bypass graft surgery with bilateral internal mammary artery. Short-term results]. / Cirugía de revascularización de miocardio usando arteria mamaria interna bilateral. Resultados a corto plazo.

INTRODUCTION: Coronary artery bypass graft (CABG) surgery remains the reference standard in the treatment of multivessel coronary disease. Several studies have shown that CABG with bilateral internal mammary arteries (BIMA) has better results in long-term survival. METHODOLOGY: A retrospective study was conducted on CABG surgeries with BIMA from January 2012 to December 2015 in the National Cardiovascular Institute, INCOR, EsSalud, Peru. The objectives were to determine the mortality and major cardiovascular events at 30 days follow-up. RESULTS: Of the 36 patients subjected to CABG surgery with BIMA, the 30-day mortality was 0%, with major cardiovascular events occurring in 5.56% of patients (Stroke 0%, postoperative myocardial infarction 5.56%, need of new coronary intervention 0%). The incidence of mediastinitis and/or sternal reconstruction was 0%. Superficial wound infection was observed in 7 patients, with there being no significant difference between diabetics and non-diabetics (25% vs. 16.66%, OR=3.3, P=.88), or between patients with or without overweight (19.23% vs. 20%, respectively, OR=.95; 95% CI, P=.68). CONCLUSIONS: CABG surgery with BIMA is a safe procedure, with low rates of mortality and major cardiovascular events in the short-term.

Aortic valve reconstruction surgery with Ozaki technique: initials results from a single center / Cirugía de reconstrucción de válvula aórtica con técnica de Ozaki: resultados iniciales en un centro de referencia

Abstract Background: Aortic valve (AV) replacement is the gold standard treatment for severe symptomatic AV disease. Recently, AV reconstruction surgery (Ozaki procedure) emerges as a surgical alternative with good results in the medium term. Methods: We retrospectively analyzed 37 patients who underwent AV reconstruction surgery between January 2018 and June 2020 in a national reference center in Lima, Peru. The median age was 62 years, interquartile range (IQR: 42-68). The main indication for surgery was AV stenosis (62.2%), in most cases due to bicuspid valve (19 patients, 51.4%). Twenty-two (59.4%) patients had another pathology with surgical indication associated to AV disease, 8 (21.6%) had dilatation of the ascending aorta with indication for replacement. Results: One in-hospital death occurred (1/38, 2.7%) due to perioperative myocardial infarction. There was a significant reduction in the medians of the peak (70 mmHg, CI 95% = 50.03-79.86 vs. 14 mmHg, CI 95% = 11.93-17.5, p < 0.0001) and mean (45.5 mmHg CI 95% = 30.6-49.68 vs. 7 mmHg, CI 95% = 5.93-9.6, p < 0.0001) AV gradients when we compared baseline characteristics with first 30-days results. In an average of 19 (± 8.9) months of follow-up, survival, reoperation-free survival for valve dysfunction, and survival free of AV insufficiency ≥ II were 97.3%, 100% and 91.9%, respectively. Significant reduction in the medians of the peak and mean AV gradients was maintained. Conclusions: AV reconstruction surgery showed optimal results in term of mortality, reoperation-free survival, and hemodynamic characteristics of the neo-AV.

Resumen Introducción: El reemplazo de la válvula aórtica es el tratamiento de elección para la valvulopatía aórtica severa sintomática. Recientemente, la cirugía de reconstrucción valvular aórtica (procedimiento de Ozaki) emerge como una alternativa quirúrgica con buenos resultados a mediano plazo. Métodos: Analizamos retrospectivamente 37 pacientes intervenidos de reconstrucción de válvula aórtica entre enero de 2018 y junio de 2020 en un centro de referencia nacional en Lima, Perú. La mediana de edad fue de 62 años (rango intercuartílico: 42-68). La estenosis de la válvula fue la principal indicación de cirugía (62.2%), en la mayoría de los casos por válvula bicúspide (19 pacientes, 51.4%). 22 (59.4%) pacientes presentaban otra patología con indicación de cirugía, 8 (21.6%) presentaban dilatación de la aorta ascendente con indicación de reemplazo. Resultados: La mortalidad intrahospitalaria fue de 1/38, 2.7%, por infarto de miocardio perioperatorio. Hubo una reducción significativa en las medianas del gradiente máximo (70 mmHg, IC 95% = 50.03-79.86 vs. 14 mmHg, IC 95% = 11.93-17.5, p < 0.0001) y gradiente medio (45.5 mmHg IC 95% = 30.6-49.68 vs. 7 mmHg, IC 95% = 5.93-9.6, p < 0.0001) de la válvula aórtica cuando comparamos las características basales con los resultados de los primeros 30 días. En una media de 19 (± 8.9) meses de seguimiento la sobrevida fue del 97.3%; la sobrevida libre de reoperación por disfunción valvular, 100% y la sobrevida libre de insuficiencia aórtica ≥ II, 91.9%, respectivamente. Se mantuvo una reducción significativa en las medianas de los gradientes máximo y medio de la válvula aórtica. Conclusiones: La cirugía de reconstrucción de válvula aórtica con pericardio autólogo mostró resultados óptimos en términos de mortalidad, supervivencia libre de reoperación y características hemodinámicas de la neo-válvula.

TNF-alpha neutralizing antibody blocks thermal sensitivity induced by compound 48/80-provoked mast cell degranulation.

BACKGROUND: Neuro-inflammatory circuits in the tissue regulate the complex pathophysiology of pain. Protective nociceptive pain serves as an early warning system against noxious environmental stimuli. Tissue-resident mast cells orchestrate the increased thermal sensitivity following injection of basic secretagogue compound 48/80 in the hind paw tissues of ND4 mice. Here we investigated the effects of pre-treatment with TNF-α neutralizing antibody on compound 48/80-provoked thermal hyperalgesia. METHODS: We treated ND4 Swiss male mice with intravenous anti-TNF-α antibody or vehicle 30 minutes prior to bilateral, intra-plantar compound 48/80 administration and measured changes in the timing of hind paw withdrawal observed subsequent to mice being placed on a 51oC hotplate. We also assessed changes in tissue swelling, TNF-α gene expression and protein abundance, mast cell degranulation, and neutrophil influx in the hind paw tissue. FINDINGS: We found that TNF-α neutralization significantly blocked thermal hyperalgesia, and reduced early tissue swelling. TNF-α neutralization had no significant effect on mast cell degranulation or neutrophil influx into the tissue, however. Moreover, no changes in TNF-α protein or mRNA levels were detected within 3 hours of administration of compound 48/80. INTERPRETATION:   The neutralizing antibodies likely target pre-formed TNF-α including that stored in the granules of tissue-resident mast cells. Pre-formed TNF-α, released upon degranulation, has immediate effects on nociceptive signaling prior to the induction of neutrophil influx. These early effects on nociceptors are abrogated by TNF-α blockade, resulting in compromised nociceptive withdrawal responses to acute, harmful environmental stimuli.

Cirugía de revascularización de miocardio usando arteria mamaria interna bilateral. Resultados a corto plazo / Coronary artery bypass graft surgery with bilateral internal mammary artery. Short-term results

Resumen Introducción: La cirugía de revascularización de miocardio (RVM) sigue siendo el gold standard en el tratamiento de la enfermedad coronaria multiarterial. Se ha demostrado que la RVM con ambas arterias mamarias internas (AMI) tiene mejor resultado de sobrevida a largo plazo. Metodología: Investigación retrospectiva de las cirugías de RVM con AMI bilateral, realizadas en el Instituto Nacional Cardiovascular-INCOR-EsSalud entre enero de 2012 a diciembre de 2015. Los objetivos fueron determinar la mortalidad por cualquier causa y los eventos cardiovasculares mayores a 30 días de seguimiento. Resultados: Treinta y seis pacientes fueron operados con AMI bilateral. No tuvimos mortalidad a 30 días. Los eventos cardiovasculares mayores se presentaron en el 5.56% de los pacientes (stroke 0%, infarto de miocardio posquirúrgico 5.56%, necesidad de nueva intervención coronaria 0%). La incidencia de mediastinitis y/o reconstrucción esternal fue de 0%. Siete pacientes tuvieron infección superficial de la herida, no hubo diferencia significativa entre los diabéticos y los no diabéticos (25% vs. 16.66%, OR: 3.3, p = 0.88) o entre los pacientes con o sin sobrepeso (19.23% vs. 20%, respectivamente, OR: 0.95, IC 95%, p = 0.68) para presentar infección de herida. Conclusiones: La RVM con AMI bilateral es un procedimiento seguro, con bajas tasas de mortalidad y de eventos cardiovasculares mayores a corto plazo. © 2016 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. Este es un artículo Open Access bajo la licencia CC BY-NC-ND (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Abstract Introduction: Coronary artery bypass graft (CABG) surgery remains the reference standard in the treatment of multivessel coronary disease. Several studies have shown that CABG with bilateral internal mammary arteries (BIMA) has better results in long-term survival. Methodology: A retrospective study was conducted on CABG surgeries with BIMA from January 2012 to December 2015 in the National Cardiovascular Institute, INCOR, EsSalud, Peru. The objectives were to determine the mortality and major cardiovascular events at 30 days followup. Results: Of the 36 patients subjected to CABG surgery with BIMA, the 30-day mortality was 0%, with major cardiovascular events occurring in 5.56% of patients (Stroke 0%, postoperative myocardial infarction 5.56%, need of new coronary intervention 0%). The incidence of mediastinitis and/or sternal reconstruction was 0%. Superficial wound infection was observed in 7 patients, with there being no significant difference between diabetics and non-diabetics (25% vs. 16.66%, OR = 3.3, P = .88), or between patients with or without overweight (19.23% vs. 20%, respectively,OR = .95; 95% CI, P = .68). Conclusions: CABG surgery with BIMA is a safe procedure, with low rates of mortality and major cardiovascular events in the short-term. © 2016 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Disección traumática de la arteria carótida interna y embolismo cerebral en un jugador de fútbol: reporte del primer caso / Blunt carotid injury and brain embolism in soccer player: first case report

Reportamos el caso de un varón de 18 años quien sufrió contusión cervical por impacto con balón de fútbol. Tres días después fue hospitalizado con hemiplejia derecha directa y afasia de expresión. La resonancia magnética cerebral mostró lesión isquémica izquierda en ganglios basales. El doppler carotideo evidenció trombo desde el origen de la arteria carótida común izquierda extendida a la arteria carótida interna izquierda (CII) y la angiotomografía documentó disección de CII (lesión traumática carotídea tipo IV). Se optó por anticoagulación con warfarina y fisioterapia de rehabilitación; con evolución favorable. La incidencia de la injuria traumática carotídea es muy rara, más aún en futbolistas; el tratamiento es aún controversial, por lo que consideramos de interés el reporte de este caso.

We report the case of an 18-year-old male patient who suffered cervical trauma with a soccer ball. He presented three days after with right hemiparesis and expressive aphasia. The magnetic resonance image showed an ischemic lesion on the left basal ganglia area. The Doppler ultrasound revealed a thrombus extending from the left common carotid artery to the left internal carotid artery, and the angio-computed tomographic scan revealed a dissection of the left internal carotid artery (carotid lesion type IV). Anticoagulation with warfarin and physiotherapy were started with good clinical evolution. The traumatic injury of the carotid artery is very rare. Treatment is controversial, so we consider interest report of this case.

Comparación entre estimulación cardiaca en tracto de salida y ápex del ventrículo derecho / Comparison between cardiac stimulation in the outflow tract and right ventricular apex

El ápex de ventrículo derecho (AVD) es el sitio convencional de estimulación cardiaca; sin embargo, no ha conseguido un patrón de activación y sincronía fisiológico. La evidencia de su efecto deletéreo ha hecho que se cuestione su práctica tradicional, por lo que nace el interés de búsqueda de sitios alternativos. El tracto de salida de ventrículo derecho (TSVD) ha demostrado ser un lugar adecuado para estimulación, sin diferencias entre umbrales de estimulación entre ambos sitios. Objetivo: Comparar los resultados del implante a nivel del ápex con los del implante en tracto de salida de ventrículo derecho. Material y métodos: Estudio descriptivo, comparativo de serie de casos retrospectivo. Se incluyeron 54 pacientes con implante de marcapaso entre 2010 y 2011. Se tomaron en cuenta datos clínicos, datos del implante propiamente dicho y sus complicaciones. Resultados: La edad promedio fue 73,7 años. La indicación más frecuente de implante fue bloqueo auriculoventricular (55,6%). La vía de acceso del electrodo ventricular fue disección de vena cefálica izquierda (76,7%). En 66,7% se consiguió estimulación en AVD y en 33,3% en TSVD. La complicación más frecuente fue hematoma de bolsillo (7,4%). No se evidenció diferencias en parámetros y umbrales de estimulación al momento del implante en ambos grupos. Conclusiones: El TSVD ha demostrado ser un lugar adecuado para estimulación; no existiendo diferencias en los umbrales estimulación o impedancia con el AVD.

The right ventricular apex (RVA) is the conventional pacing site, however, but it does not induce a pattern of activation and physiological synchrony. The evidence of its deleterious effect has raised questions about the traditional practice and therefore, an alternative site is being searched. The right ventricle outflow tract (RVOT) has proven to be a suitable site for stimulation, with not difference in stimulation thresholds between the two sites. Objective: Compare the outcomes of the implantation of pacemakers in the apex and in the outflow tract of the right ventricle. Methods: A descriptive and retrospective case series. We included 54 patients with pacemaker implantation between 2010 and 2011. Patient records were reviewed for clinical data, implant itself and its complications. Results: Mean age was 73.7 years. The most common indication for implantation was atrioventricular block (55.6%). The path to address ventricular electrode was through left cephalic vein dissection (76.7%). The stimulation was achieved 66.7% in RVA and 33.3% in RVOT. The most common complication pocket hematoma (7.4%). No differences were evident in the stimulation parameters and stimulation thresholds in both groups. Conclusions: RVOT has proven to be a suitable site for stimulation, no differences were found in stimulation thresholds or the RVA impedance.

Incidencia del antigeno de superficie de la hepatitis en donantes de sangre

La investigación de la incidencia del antígeno de superficie de la hepatitis demostró, entre 91307 donantes voluntarios de sangre, que el 0.5% era positivo. Efectuamos la investigación en el Banco de Sangre de la Cruz Roja Provincial del Guayas, en Guayaquil, Ecuador, usando el método de Radioinmunoensayo (RIA, Abbott) desde enero de 1981 hasta diciembre de 1987 y una técnica de microelisa desde enero de 1988