Excision of the aortic wall in the surgical treatment of acute type-A aortic dissection

Between March 1986 and September 1988, 38 patients underwent extended aortic resection (aortic valve, ascending aorta, and arch) for acute type-A aortic dissection with aortic valve insufficiency; deep hypothermia and circulatory arrest were used. All patients were operated on within 17 hours of the onset of symptoms. In the first 24 patients, operation was performed by the "inclusion technique." In the last 14 patients, the "excision technique" was used: the ascending aorta and arch was excised, and the aorta was transected at the beginning of the descending thoracic tract. Excision and transection were considered essential to prevent back flow from the false lumen, which is the main source of bleeding, and to allow all anastomoses to be constructed beyond the limits of dissection. The only anastomosis to the dissected aorta was at the distal end of the graft. One of the 14 patients died (7.1%). One patient was reopened for bleeding: blood was issuing from the attachment of the carotid trunks, and the defect was repaired by interposing a bifurcated Dacron graft between the arch graft and the carotid arteries. Extended aortic excision meets the principle of either eliminating as far as possible the diseased aorta or controlling intraoperative and postoperative bleeding. An operation of great magnitude can be considered a life-saving procedure when compared with the high risk of acute type-A aortic dissection.     

Anastomosis

Esophageal anastomosis is still associated with a high rate of complications even though they have decreased considerably in recent years. Anastomotic leaks are more frequent in the neck than in the chest, and related mortality rate is not different. The leakage incidence does not depend on suture materials or on technical modalities used to perform the anastomosis. In fact, there is no difference between the leakage rate when comparing manual and mechanical anastomoses. The leak incidence after both mechanical and manual anastomoses is much higher in collective reviews than in reports coming from leading centers. Frequent esophageal surgeons can learn from their previous experience and therefore avoid technical errors, whereas casual esophageal surgeons do not have this opportunity. Performing an esophageal anastomosis is a technical matter, and suture healing is independent of the patient's biologic situation. Anastomotic fibrotic stricutures are frequent after both manual and mechanical anastomoses, and most can be avoided by meticulous suturing technique.

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Resumen La anastomosis esofágica todavía se asocia con una elevada incidencia de complicaciones, a pesar de que éstas han descendido en forma considerable en los últimos años. Las fugas anastomóticas son más frecuentes en el cuello que en el tórax y las tasas de mortalidad no son diferentes. La rata de fuga anastomótica no depende de los materiales de sutura o de las modalidades técnicas que se utilicen para realizar la anastomosis. De hecho no hay diferencia en cuanto a la rata de fugas entre las anastomosis manuales y las mecánicas. La incidencia de fuga, tanto en las manuales como en las mecánicas, es bastante más alta en las revisiones colectivas que en los reportes emanados de los centros médicos de mayor importancia. Los cirujanos especialistas en esófago tienen la posibilidad de aprender de sus experiencias previas y con ello evitar los errores técnicos, en tanto que aquellos cirujanos ocasionales no la poseen. La realización de una anastomosis esofágica es un asunto técnico y la cicatrización de la sutura es independiente de la condición biológica del paciente. Las estrecheces fibróticas de las anastomosis son frecuentes luego de las anastomosis manuales, al igual que luego de las anastomosis mecánicas y la mayoría puede ser evitada mediante una técnica meticulosa.

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Résumé Le taux de complications des anastomoses oesophagiennes, même s'il y en a moins ces dernières années, reste toujours élevé. La fréquence de fistules est plus grande quand l'anastomose est faite au cou par rapport au thorax, mais la mortalité n'en est pas très différente. L'incidence de fistules ne dépend ni du matériau de suture ni des modalités d'anastomoses utilisées. Il n'y a aucune différence lorsque les anastomoses manuelles sont comparées aux anastomoses méchaniques: L'incidence des fistules, que ce soit à la main ou à la machine est plus élevée dans les séries collectives par rapport à celle des centres spécialisés. Les chirurgiens qui font des anastomoses de façon régulière ont la possibilité de profiter de leur expérience et ainsi d'éviter les erreurs techniques, alors que le chirurgien occasionnel de l'oesophage n'a pas cette possibilité. L'anastomose oesophagienne est techniquement difficile et la cicatrisation est indépendante de l'état clinique et biologique du patient. Les sténoses fibreuses sont aussi fréquentes après les anastomoses manuelles qu'après les anastomoses méchaniques, mais la plupart peuvent être évitées par une technique méticuleuse.

     

Early-onset encephalomyopathy associated with tissue-specific mitochondrial DNA depletion: A morphological,biochemical and molecular-genetic study

A male infant, born from consanguineous parents, suffered from birth with a progressive neuromuscular disorder characterized by psychomotor delay, hypotonia, muscle weakness and wasting, deep-tendon areflexia and spastic posture. High levels of lactic acid in blood and cerebrospinal fluid suggested a mitochondrial respiratory chain defect. Muscle biopsy revealed raggedred and cytochromec oxidase-negative fibres, lipid accumulation and dystrophic changes. Multiple defects of respiratory complexes were detected in muscle homogenate, but cultured fibroblasts, myoblasts and myotubes were normal. Southern blot analysis showed markedly reduced levels of mitochondrial DNA (mtDNA) in muscle, while lymphocytes, fibroblasts and muscle precursor cells were normal. Neither depletion of mtDNA nor abnormalities of the respiratory complexes were observed in innervated muscle fibres cultured for as long as 4 months. No mutations were observed in two candidate nuclear genes,mtTFA andmtSSB, retro-transcribed, amplified and sequenced from the proband's mRNA. Sequence analysis of the mtDNA D-loop and of the origin of replication of the mtDNA light strand failed to identify potentially pathogenic mutations of these replicative elements in the proband's muscle mtDNA. Our findings indicate that mtDNA depletion is due to a nuclear encoded gene and suggest that the abnormality underlying defective mtDNA propagation must occur after muscle differentiation in vivo.     

Postzygotic instability of the myotonic dystrophy p[AGC]n repeat supported by larger expansions in muscle and reduced amplifications in sperm

We have analysed the [AGC] expansion in leucocytes, muscle and sperm from 17 individuals affected by myotonic dystrophy (DM). Skeletal muscle showed a larger repeat number than leucocytes in the same patient. A similar degree of expansion was detected in differently affected muscles of a single patient. The germline mutation ( 350 repeats) was expanded in somatic cells of the progeny in all patients examined. Our results provide evidence of an early postzygotic instability of the [AGC] repeat in DM.     

Neuroblastoma in two siblings supports the role of 1p36 deletion in tumor development

Familial neuroblastoma occurs rarely. We studied a family with three children; one of them has a disseminated (stage 4) and another has a localized (stage 2) neuroblastoma. We observed subtelomeric locus D1Z2 (1p36) deletion in both tumors by using double-color fluorescence in situ hybridization. The MYNC gene was found in single copy in both tumors. Loss of heterozygosity (LOH) and restriction fragment length polymorphism analyses were performed by using DNA from frozen tumor cells and from microdissected tumor areas excised from paraffin-embedded sections. We detected somatic LOH at locus D1S468 (1p36) in a tumor-cell population with a trisomy 1 of the stage-2 patient. Neuroblastoma cells of the stage-4 patient were diploid and showed allelic loss at the following loci: D1S172, D1S80, D1S94, D1S243, D1S468, D1S214, D1S241, and D1S164. Haplotype study showed that the siblings inherited the same paternal 1p36-->pter chromosome region by homologous recombination and that, in the two tumors, arm 1p of different chromosomes of maternal origin was damaged. Our results suggest that the siblings inherited the predisposition to neuroblastoma associated with paternal 1p36 region and that tumors developed as a consequence of somatic loss of the maternal 1p36 allele.     

Mesenteric cystic neoformations: Report of two cases

(Received for publication on Apr. 28, 1997; accepted on May 15, 1998)     

Prognostic value of galactose elimination capacity,aminopyrine breath test,and ICG clearance in patients with cirrhosis

Seventy-eight patients with cirrhosis were prospectively followed for up to 20 months, on the average. At entry into the study, galactose elimination capacity, aminopyrine breath test, and ICG clearance were measured. At the end of the study, 27 patients had died. Univariate analysis using the Kaplan-Meier method showed that both quantitative liver function tests (galactose elimination capacity:P<0.025; aminopyrine breath test:P<0.001; ICG clearance:P<0.005) and common clinical and biochemical data (encephalopathy:P<0.001; ascites:P<0.001; serum bilirubin:P<0.005; serum albumin:P<0.001; prothrombin index:P<0.05) were significant predictors of survival. To investigate whether quantitative liver function tests could contribute to a better definition of the prognosis, once Pugh score had already been taken into account, a multiple regression analysis according to the Cox model was performed. Pugh score and galactose elimination capacity resulted in the only independent prognostic covariates. From them a prognostic index was calculated, and the model was validated in an additional sample of 70 patients investigated according to the same protocol. The contribution GEC gave to the assessment of overall prognosis over that obtained using the Pugh score was slight, as estimated by the statistical parameters of the Cox's model, but was significant as assessed by a ROC curve analysis (P=0.05). These data show that all quantitative liver function tests were predictors of survival in cirrhosis, and that the galactose elimination capacity added some new prognostic information to those already available using the Child-Turcotte-Pugh classification.This study was supported in part by a grant from the Italian Ministry of Education (National Project Liver Cirrhosis). Part of this study was presented at the 22nd Meeting of the European Society for Clinical Investigation, Graz, Austria, April 20–23, 1988.     

Approach to the patient in vegetative state. Part III: prognosis

To define a vegetative state (VS) as permanent is to declare its irreversibility. In 1994 a North-American multidisciplinary task force, by extensively analysing the literature, concluded that the recovery of consciousness from a post-traumatic or non-traumatic VS is unlikely after 12 and 3 months respectively. These conclusions did not obtain unanimous consent. The term permanent was in fact inappropriately used to define either the loss of consciousness or of function. Furthermore, patients with traumatic brain injury have been shown to recover the consciousness in a substantial greater percentage (6-7%) than previously appreciated (1.6%). This is hardly compatible with the peremptoriness of the term permanent, which should be used only in case of certainty. Ancillary tests are important in defining the prognosis. Patients in deep coma after an anoxic brain injury can be predicted as having a poor prognosis (death or permanent VS) with 100% specificity within one week of the insult. Magnetic resonance of the brain can predict patients at high risk of permanent VS within 6-8 weeks of a traumatic brain injury. In conclusion, the available evidence does not permit to define with certainty the patients who have irremediably lost their consciousness after a devasting brain insult. However, it seems possible to reliably define the risk of severe disability. Whether or not this knowledge might or should be used to titrate the intensity of therapeutic approach is to be defined. In this respect, it is central the definition of what an "acceptable outcome" is, certainly not an exclusive medical attribution.     

Systemic and pulmonary vascular resistance in brain death

BACKGROUND: Hemodynamic instability is known to affect brain dead subjects and it can be dangerous for the viability of transplantable organs. Aim of the present study was to assess the hemodynamic performance in brain dead subjects, the changes during the legal observation period and the results of therapeutic management. METHODS: The authors evaluated 28 consecutive adult brain dead subjects, all in intensive treatment, controlled ventilation, infusion therapy and/or dopamine administration and continuous direct monitoring of arterial pressure. Ten hemodynamic parameters have been registered by the thermodilution method and the Swann-Ganz catheter. The Legal Committee performed measurements at the beginning (T0) and the end (T6) of the observation period, which lasts 6 hours according to the current law on death certification (Law N. 578/93). RESULTS: Low systemic and pulmonary vascular resistances have been documented in the majority of subjects (75%), both treated only with fluids and with the additional dopamine administration (dosage lower than 10 ug/Kg/min). The above-mentioned reduction was similar at the two different monitored times (T0 and T6). CONCLUSIONS: This situation can be ascribed to the destruction of the cerebral vasoactive centers and the consequent hypotension is due to autonomic nervous system dysfunction. Hemodynamic instability must be treated by fluids and inotropic drugs, but they may cause cardiac and respiratory problems, thus it is suggested to use also low doses of vasoconstrictive drugs, provided that cardiac condition allows this therapeutic strategy.