Resultados iniciales con criopreservación de glándulas paratiroides y potenciales aplicaciones / Histological integrity and functional viability results of previously cryopreserved human para thyroid tissue

Objetivo: Analizar la integridad histológica y viabilidad funcional de tejido paratiroideo criopreservado, con miras a un potencial trasplante futuro. Material y método: Se criopreservaron muestras de tejido paratiroideo proveniente de 14 pacientes operados por HPT (8 secundarios, 3 terciarios , 1 primario recidivado y dos hiperplasias primarias). Fraccionado en porciones de 2 x 3 mm, el material fue preservado en suero + solución de Hanks + DMSO y congelados hasta -90°C, conservándolo en nitrógeno líquido. Luego de seis meses, el material de 4 pacientes fue parcialmente descongelado y estimulado con solución de Cloruro de Ca++, midiéndose la secreción de PTH y estudiando la histología con H y E y con el método de Tunnel para apoptosis. Resultados: Se observó en las cuatro muestras un patrón similar de respuesta, con un pico inicial de secreción, un descenso a la hora, y un nuevo ascenso a las dos horas del estímulo. El estudio histológico de las piezas mostró integridad histológica luego de seis meses de criopreservación, pero importante depauperización celular luego del estímulo. Conclusiones: En la muestra analizada, la criopreservación del tejido paratiroideo ha permitido conservar su integridad histológica, así como sus capacidades secretorias básicas. El fenómeno apoptótico que invariablemente acompaña a la estimulación prolongada in vitro, requiere nuevas investigaciones que permitan controlarlo

Resultados iniciales con criopreservación de glándulas paratiroides y potenciales aplicaciones / Histological integrity and functional viability results of previously cryopreserved human para thyroid tissue

Objetivo: Analizar la integridad histológica y viabilidad funcional de tejido paratiroideo criopreservado, con miras a un potencial trasplante futuro. Material y método: Se criopreservaron muestras de tejido paratiroideo proveniente de 14 pacientes operados por HPT (8 secundarios, 3 terciarios , 1 primario recidivado y dos hiperplasias primarias). Fraccionado en porciones de 2 x 3 mm, el material fue preservado en suero + solución de Hanks + DMSO y congelados hasta -90ºC, conservándolo en nitrógeno líquido. Luego de seis meses, el material de 4 pacientes fue parcialmente descongelado y estimulado con solución de Cloruro de Ca++, midiéndose la secreción de PTH y estudiando la histología con H y E y con el método de Tunne

Mortality and morbidity from intra-aortic balloon pumps. Risk analysis.

BACKGROUND: The purpose of this study, was to assess the incidence of and predictors for mortality and morbidity in patients who required postoperative intra-aortic balloon pump (IABP) support. METHODS: We have retrospectively estimated 116 patients and data were statistically analyzed, and significant variables were evaluated with multivariate analysis. RESULTS: Mortality rate was 57.8% (67 patients). Nineteen patients (16.3%) had major vascular complications: 12 patients (10.3%) limb ischemia, 1 patient (0.9%) aortic dissection, 6 patients (5.2%) mesenteric infarction. Thirty patients (25.8%) had minor vascular complication: 23 patients (19.8%) bleeding from insertion site, 7 (6%) patients infection of insertion site. Limb ischemia was resolved by IABP removal (10 patients), thrombectomy (2 patients). No patient required limb amputation. Sixty patients (51.7%) had renal insufficiency, of which 40 patients needed dialysis. Fifteen patients (10.3%) had neurological complications, 13 patients (11.2%) thrombocytopenia and 5 patients (4.3%) sepsis. CONCLUSIONS: The incidence of IABP insertion in our institution was 1.5%. Mortality rate is similar to mortality of other studies in which the IABP has been inserted in the postoperative period. We have found that timing of IABP insertion, thrombocytopenia, presence of peripheral vascular disease and the redo intervention are independent predictors of mortality. We also found that female sex, diabetes, history of cigarette smoking and preoperative use of antiplatelet drugs are independent predictors of limb ischemia. The following factors are instead independent predictors of renal insufficiency: postoperative ejection fraction lower than 40% and non use of dobutamine in the postoperative period.

Haemolysis due to active venous drainage during cardiopulmonary bypass: comparison of two different techniques.

To facilitate mini-access for cardiac surgery, two different methods of active venous drainage are used: vacuum assisted drainage and centrifugal pump aspiration on the venous line. The aim of this study was to compare the haemolysis produced using these two techniques. From June to December 1999, 50 consecutive patients were operated on using a ministernotomy. All of these patients had valvular surgery for either valve repair or valve replacement (9 MVRepair, 11 MVR, 29 AVR, 1 AVR + MVR). They were randomized into two groups: Group A, 25 patients who underwent surgery where vacuum assisted drainage was used, and Group B, 25 patients where kinetic asssisted venous drainage with centrifugal pump venous aspiration was used. Patient characteristics of both groups were similar for age, gender, body weight, body surface area, height, cardiopulmonary bypass (CPB) time, aortic crossclamp time, priming volume, cardioplegia volume, haemoglobin concentration, haematocrit, serum creatinine, bilirubin, lactate dehydrogenase (LDH), serum glutamic oxaloacetic transaminase (sGOT), serum glutamic pyruvic transaminase (sGPT), aptoglobin, reticulocytes, and platelet count. We checked all these laboratory parameters preoperatively, at the end of CPB, and 2 and 24 h after operation. We also checked haemoglobinuria at these same time points. We assessed blood loss at 6, 12, and 24 h after the operation and calculated total postoperative bleeding. There was a tendency towards a greater increase in LDH, sGOT and sGPT in Group A more than in Group B, but these data did not reach statistical significance. Platelet count was always lower in Group A and aptoglobin increased in Group A more than in Group B. More patients in Group A had haemoglobinuria. These findings indicate that haemolysis is increased more in patients treated with vacuum assisted drainage, when compared to the rise in haemolysis in those treated with centrifugal pump venous drainage. Total bleeding is also greater in Group A.

Porcine valve durability: a comparison between Hancock standard and Hancock II bioprostheses.

Two series of patients who received a Hancock standard (HS) (1970 to 1983) and a Hancock II (HII) (1983 to 1992) porcine bioprosthesis were reviewed to compare bioprosthetic durability. Patients with HS porcine bioprostheses (n = 769) differed from those with HII bioprostheses mostly in mean age at operation (47 +/- 12 versus 62 +/- 9 years; p < 0.001); the latter prosthesis was implanted mostly in patients older than 50 years. At 8 years after operation, actuarial survival was 57% +/- 4% after aortic, 61% +/- 3% after mitral, and 39% +/- 7% after mitral-aortic valve replacement with the HS bioprosthesis; actuarial survival was 51% +/- 9% after aortic, 66% +/- 6% after mitral, and 49% +/- 10% after mitral and aortic valve replacement with an HII bioprosthesis. No cases of structural deterioration of HII bioprostheses were observed at 8 years in any patients. Actuarial freedom from structural valve deterioration was 78% +/- 4% after aortic, 88% +/- 3% after mitral, and 79% +/- 7% after mitral-aortic valve replacement with an HS bioprosthesis at 8 years. In all patients greater than 50 years of age, actuarial freedom from structural valve deterioration at 8 years was 90% +/- 3% in patients with an HS bioprosthesis and 100% in those with an HII bioprosthesis (p = 0.08). A trend to an improved durability of the HII bioprosthesis compared with the HS was observed during the first 8 postoperative years. Because these results could be influenced partly by the age difference in the two series of patients, a longer follow-up is needed to confirm these data.

Hancock II porcine bioprosthesis: excellent durability at intermediate-term follow-up.

OBJECTIVES: This study aimed to assess the clinical performance and durability of a new generation of porcine valve, the Hancock II bioprosthesis, at intermediate-term follow-up. BACKGROUND: Standard porcine bioprostheses undergo progressive structural deterioration, mainly due to cusp and commissural calcification, affecting durability and requiring reoperation. The Hancock II bioprosthesis, which is currently undergoing clinical investigation, is made from a porcine aortic valve treated with a calcium-retarding agent (sodium dodecyl sulfate [T6]), which should delay onset of calcification and increase durability. METHODS: From May 1983 to December 1992, we used the Hancock II bioprothesis in aortic (59 patients), mitral (101 patients) and mitral-aortic (25 patients), valve replacement procedures. Postoperative follow-up ranged from 0.1 to 8.7 years (mean [+/- SD] 4.5 +/- 2.6 years) and was 100% complete. Freedom from major postoperative events was calculated at 7 years for patients with aortic valve replacement and at 8 years for those with mitral and mitral-aortic valve replacement. RESULTS: The actuarial survival rate was 48 +/- 10%, 76 +/- 3% and 63 +/- 6%; freedom from valve-related mortality was 91 +/- 4%, 94 +/- 2% and 89 +/- 6%; freedom from thromboembolism was 80 +/- 11%, 90 +/- 2% and 79 +/- 7%; and freedom from reoperation was 100%, 97 +/- 1% and 89 +/- 6% after aortic, mitral and mitral-aortic valve replacement, respectively. No structural valve deterioration occurred. CONCLUSIONS: At intermediate-term follow-up the Hancock II bioprosthesis showed excellent durability in all positions. However, the effectiveness of anticalcification treatment must be assessed with longer follow-up studies.

Traumatismos craneofaciales / Diagnostic Imaging of craneofacial fractures

La valoración precisa de las fracturas craneofaciales es indispensable para instituir un tratamiento correcto y de esa manera evitar defectos anatómicos,funcionales y estéticos. En la actualidad el algoritmo de estudio de los traumatismos craneofaciales incluye las radiografías convencionales y la tomografía computada. Se presenta una experiencia conjunta de radiólogos y cirujanos en el estudio de 63 pacientes, 51 hombres y 12 mujeres, con traumatismos craneofaciales asistidos en nuestra institución en los últimos 4 años, con un rango etario que va de 15 a 38 años y una edad media de 30,8 años. Se analizan los hallazgos radiológicos en correlación con la clínica y el mecanismo lesional, así como las técnicas de examen más adecuadas para cada tipo de fractura. Concluímos que la tomografía computada (TC) es el método ideal en la valoración del paciente con traumatismo craneofacial en la planificación del tratamiento quirúrgico

Traumatismos craneofaciales / Diagnostic Imaging of craneofacial fractures

La valoración precisa de las fracturas craneofaciales es indispensable para instituir un tratamiento correcto y de esa manera evitar defectos anatómicos,funcionales y estéticos. En la actualidad el algoritmo de estudio de los traumatismos craneofaciales incluye las radiografías convencionales y la tomografía computada. Se presenta una experiencia conjunta de radiólogos y cirujanos en el estudio de 63 pacientes, 51 hombres y 12 mujeres, con traumatismos craneofaciales asistidos en nuestra institución en los últimos 4 años, con un rango etario que va de 15 a 38 años y una edad media de 30,8 años. Se analizan los hallazgos radiológicos en correlación con la clínica y el mecanismo lesional, así como las técnicas de examen más adecuadas para cada tipo de fractura. Concluímos que la tomografía computada (TC) es el método ideal en la valoración del paciente con traumatismo craneofacial en la planificación del tratamiento quirúrgico(AU)

Early and late outcome after reoperation for prosthetic valve dysfunction: analysis of 549 patients during a 26-year period.

Factors influencing operative mortality and late survival of 549 patients undergoing a first reoperation for prosthetic valve failure during the interval from 1966 to 1992 were analyzed; 347 patients had reoperation on a mitral prosthesis, 173 on an aortic prosthesis and 29 on both aortic and mitral prostheses. Univariate analysis showed that hospital mortality was higher in patients in functional class IV compared with those in class II-III (35% vs. 8%, p < 0.001), in those who required emergency reoperation (57% vs. 11%, p < 0.001), in those reoperated for endocarditis (59%) or valve thrombosis (43%) compared with those reoperated for structural valve deterioration (9%, p < 0.001), and in those with a failing mechanical prosthesis compared to patients with a bioprosthesis (21% vs. 10%, p < 0.05). Furthermore, operative mortality decreased from 41% in the period from 1966 to 1977, to 12% from 1977 to 1983 and to 8% from 1984 to 1992 (p < 0.001). Hospital survivors were followed from 0.1 to 22 years (mean follow-up 11 +/- 5 years) with an overall actuarial survival at 15 years of 24 +/- 5%. At 15 years actuarial survival is 24 +/- 5% for patients in preoperative functional class II-III and 20 +/- 6% for those in functional class IV (p < 0.05). It is concluded that in prosthetic valve recipients both early and late outcome is greatly influenced by preoperative clinical status. Increasing surgical experience, better myocardial protection and patient management have contributed to reducing the operative risk. More accurate patient follow up and possibly earlier reoperation might also improve the long term outcome.

Reoperation in patients with a bioprosthesis in the mitral position: indications and early results.

Our experience with 221 patients undergoing a first reoperation for bioprosthesis failure in the mitral position is reviewed. Most, (196, 89%) were reoperated because of structural valve deterioration, 16 (7%) had periprosthetic leak and nine (4%) had prosthetic endocarditis. Operative mortality (23 patients overall, 10.4%) was significantly higher in those patients who were in NYHA functional class IV or had impaired left ventricular function, in those reoperated because of prosthetic endocarditis and those undergoing emergency reoperation. Those patients who had structural valve deterioration, good left ventricular function and who were reoperated electively had the lowest operative risk. With increasing experience and the use of standardized surgical techniques, the results of reoperation for bioprosthetic failure have improved considerably in recent years. A further reduction in operative risk can be expected with better patient selection, obtained through more careful non-invasive assessment of valve performance to detect the initial signs of bioprosthetic failure.

Long term survival without anticoagulation after aortic valve replacement with a Lillehei-Kaster prosthesis. A case report.

A patient who underwent aortic valve replacement with a Lillehei-Kaster prosthesis developed an early duodenal ulcer requiring suspension of warfarin treatment. Subsequently he was managed without oral anticoagulants, receiving only antiplatelet agents, starting from the third postoperative year. Neither thromboembolic nor hemorrhagic complications occurred but at reoperation, performed almost 20 years later for prosthetic stenosis caused by a fibrous ring, and aneurysm of the ascending aorta, mild fresh thrombus was found on the prosthetic ring. Although the long term outcome of patients with a mechanical aortic prosthesis can occasionally be successful even without long term anticoagulation, such management appears to be justified only in highly selected cases.