Statement of the problem The primary objective of this thesis was to determine the best study design to evaluate the safety and effectiveness of an intermediate dose of low molecular weight heparin for secondary prevention of pregnancy associated VTE (PAVTE). An RCT was deemed unfeasible,so the use of a single arm study with prior evaluation of feasibility with a pilot study is proposed. // Methods - A systematic review was conducted to evaluate the efficacy of current strategies used for secondary prevention of PAVTE.A survey was used to elicit the non-inferiority margin. // Results - The pooled proportion of recurrent VTE in patients treated with full dose LMWH was 0.012(95% CI 0.006 to 0.02) and the rate of major bleeding was 0.025(95% CI=0.01 to 0.041). The non-inferiority margin was elicited at 2.5%. // Conclusions - Although a randomized controlled trial should be conducted whenever possible, in certain scenarios they are unfeasible. Therefore, an alternative study design should perhaps be used to evaluate the safety and efficacy of therapeutic strategies.

Venous thromboembolism (VTE) is a common disease with a myriad of presentation. It is often difficult to diagnosis with symptoms which are shared with many other disorders. Because of the overlap in symptomatology with other pathologies it is both commonly overlooked when present and commonly considered when absent. The threshold for investigating suspected VTE has dropped over time, in part due to a greater awareness of the disease among clinicians, but also because of the greater availability of diagnostic tests which are both accurate at positively diagnosing VTE and are patient friendly. This has resulted in a mushrooming of the number of diagnostic tests being performed for suspected VTE in radiology departments. As such radiology provides a window into the disease in a way that no other speciality can. All branches of medicine having their share of VTE patients but radiology provides a unique opportunity to study VTE patients as, no matter from which speciality they arise when the disease is suspected, they will almost inevitably end up undergoing a definitive radiological test. There is much still to learn about VTE however developments in modern imaging and computerised databases have advanced our understanding of this common disease. The window that radiology provides into VTE has contributed towards those advances.

Background As a major cause of morbidity and mortality treatment of venous thromboembolism is important, with the correct use of anticoagulants it is possible to greatly reduce both mortality and morbidity. Warfarin is among the most widely used anticoagulants being effective in treatment and prevention of venous thromboembolism with few negative side effects other than bleeding complications. With a narrow therapeutic window warfarin treatment requires constant monitoring and adjustments to stay effective without an increased bleeding risk. The aim of this thesis was to study the efficacy and safety of warfarin treatment in venous thromboembolic disease. Methods Using AuriculA, the Swedish national quality register for atrial fibrillation and anticoagulation, a cohort was created of patients registered with warfarin treatment during the study time January 1st 2006 to December 31th 2011, including all different indications for anticoagulation. In all four studies the study design was retrospective with information added to the cohort from the Swedish national patient register about background data and endpoints in form of bleeding complications in all studies and thromboembolic events in study 1 and 2. In study 3 and 4 information was added from the cause of death register about occurrence of death and in study 3 cause of death. In study 3, information from the prescribed drugs register about retrieved prescriptions of acetylsalicylic acid was added. Results In study 1 the mean TTR was found to be high both among patients managed at primary healthcare centres and specialised anticoagulation clinics at 79.6% and 75.7%. There was no significant difference in rate of bleeding between the two types of managing centres being 2.22 and 2.26 per 100 treatment years. In study 2 no reduction in complication rate with increasing centre TTR was seen for patients with atrial fibrillation with few centres having centre TTR below 70% (2.9%), in contrast to previous findings by Wan et al(1). For those with warfarin due to VTE where a larger proportion of the centres had centre TTR below 70% (9.1%) there was a reduction in complication rate with increasing centre TTR. Among the 13859 patients with treatment for VTE in study 3 age (HR 1.02, CI 95% 1.01-1.03), hypertension (HR 1.29, CI 95%1.02-1.64), Cardiac failure (HR 1.55, CI 95% 1.13-2.11), chronic obstructive pulmonary disease (HR 1.43, CI 95% 1.04- 1.96), alcohol abuse (HR 3.35, CI 95% 1.97-5.71), anaemia (HR 1.77, CI 95% 1.29-2.44) and a history of major bleeding (HR 1.75, CI 95% 1.27-2.42) increased the risk of bleeding during warfarin treatment. In study 4 both those with high iTTR and those with low INR variability had a low rate of bleedings at 1.27 (1.14-1.41) or 1.20 (0.94-1.21) per 100 treatment years compared to those with low iTTR and high INR variability having a rate of bleeding at 2.91 (2.61-3.21) or 2.61 (2.36-2.86) respectively. Those with the combination of both low iTTR and high INR variability had an increased risk of bleeding, hazard ratio HR 3.47 (CI 95 % 2.89-4.17). The quartile with both the lowest iTTR and the highest INR variability had an increased risk of bleeding with a hazard ratio 4.03 (3.20-5.08) and 3.80 (CI 95%, 3.01-4.79) compared to the quartile with the highest iTTR and lowest INR variability. Conclusion It is possible to achieve a safe warfarin treatment both in specialised anticoagulation centres and in primary health care. At initiation of treatment some of the patients at high risk of bleeding can be identified using knowledge about their background. With the use of quality indicators as TTR and INR variability during treatment those at high risk of complications can be identified and analysing treatment quality on centre level gives an opportunity to identify improvement areas among managing centres. With the addition of new treatment options warfarin can still be the most suitable option for some patients, being safe and effective when well managed.

Venous valves (VVs) are critical for unidirectional blood flow from superficial and deep veins towards the heart. Congenital valve aplasia or agenesis may, in some cases, be a direct cause of vascular disease, motivating an understanding of the molecular mechanisms underlying the development and maintenance of VVs. Three gap junction proteins (Connexins), Cx37, Cx43, and Cx47, are specifically expressed at VVs in a highly polarized fashion. VVs are absent from adult mice lacking Cx37; however it is not known if Cx37 is required for the initial formation of valves. In addition, the requirement of Cx43 and Cx47 for VV development has not been studied. Here, we provide a detailed description of Cx37, Cx43, and Cx47 expression during mouse vein development and show by gene knockout that each Cx is necessary for normal valve development. The valve phenotypes in the knockout lines exhibit Cx-specific differences, however, including whether peripheral or central VVs are affected by gene inactivation. In addition, we show that a Cx47 null mutation impairs peripheral VV development but does not affect lymphatic valve formation, a finding of significance for understanding how some CX47 mutations cause inherited lymphedema in humans. Finally, we demonstrate a striking segregation of Foxc2 and NFATc1 transcription factor expression between the downstream and upstream faces, respectively, of developing VV leaflets and show that this segregation is closely associated with the highly polarized expression of Cx37, Cx43, and Cx47. The partition of Foxc2 and NFATc1 expression at VV leaflets makes it unlikely that these factors directly cooperate during the leaflet elongation stage of VV development. (C) 2016 Elsevier Inc. All rights reserved.

Introdução: flebite é um dos eventos adversos presente em grande parte das instituições de saúde podendo comprometer a assistência ao paciente. A compreensão do tema faz-se importante para que melhor possam ser trabalhadas estratégias de prevenção e para tanto, é imprescindível conhecer suas características e eventuais associações relacionadas ao seu aparecimento. O estudo teve como objetivo geral avaliar as características dos pacientes com flebites notificadas e características desses eventos adversos em um hospital de médio porte em Ribeirão Preto, São Paulo. Material e Método: trata-se de um estudo quantitativo, descritivo, exploratório, retrospectivo e transversal, aprovado pelo Comitê de Ética em Pesquisa da Escola de Enfermagem de Ribeirão Preto/USP com coleta de dados das notificações realizadas entre 2012 a 2014. Na instituição hospitalar em que o estudo foi desenvolvido, 373 pacientes apresentaram 436 episódios de flebites. Os dados foram coletados por meio de um instrumento tendo como fonte de consulta as fichas de notificação e prontuários eletrônicos dos pacientes. Resultados: a média de flebite em 2012 foi de 2,13%(±0,009), em 2013 de 2,91%(±0,010) e em 2014 de 1,84%(±0,008), inferiores a 5%, que é o aceitável; a idade média dos pacientes foi de 59,3 anos sendo 50,7% do sexo feminino e 82,8% de cor branca. A Pneumonia foi o diagnóstico que mais levou à internação e 49,6% dos pacientes tinham hipertensão. Ocorreram 436 flebites com destaque a um paciente em que ocorreram cinco flebites no período de 30 dias; a classificação da flebite com maior ocorrência foi a de grau 2 (45,4%), o calibre do cateter mais utilizado foi o 22 G (29,7%); o local mais utilizado para punção dos acessos venosos foi o membro superior esquerdo (53,4%); os profissionais que mais realizaram as punções foram auxiliares/técnicos de enfermagem (62,6%). Quanto aos medicamentos utilizados na vigência das flebites, 96,2% eram antibióticos; o tempo de permanência do cateter desde sua inserção até o momento em a flebite apareceu foi de 48 horas (31,1); 20,9% das flebites notificadas eram de punções realizadas em outros serviços, que não a instituição onde o estudo foi realizado. Ocorreu variação nos resultados de exames coletados anterior e posteriormente à ocorrência da flebite como Hemoglobina, Glóbulos Brancos, Proteína C Reativa e Plaquetas; no entanto, apenas os dois últimos apresentaram resultados estatisticamente significantes (p=0,0095 e p=0,0001 respectivamente). Observa-se resultado estatisticamente significante (p=0,0172) na associação da flebite de grau 2 com o cateter de calibre n°22 G. Conclusão: o estudo agrega conhecimentos à área da enfermagem e é o primeiro abordando este tema realizado na instituição hospitalar. Apesar de o numero de flebite ser menor que o aceitável pela literatura, é preciso empenho e dedicação para que esse índice diminua ainda mais, pois isso influencia diretamente na qualidade da assistência e na segurança do paciente / Introduction: phlebitis is one of the adverse events presented in most part of health institutions that can put assistance to patients in danger. The comprehension of this theme made of great importance for a better worked prevention strategy and therefore, it is vital to know its characteristics and casual associations related to its appearance. The study has as general objective evaluate the phlebitis patients´characteristics notified and these adverse events characteristics in a medium-sized hospital in Ribeirão Preto, São Paulo. Material and Method: it is about a quantitative, descriptive, exploratory, retrospective and transversal study, approved by the Ethical Committee in Research from Nursing School in Ribeirão Preto/USP with the notification data collection applied out between 2012 to 2014. At the hospital institution which the study was developed, 373 patients presented 436 phlebitis episodes. The data were collected through an instrument having as source the notification records and patients electronical handbooks. Results: the phlebitis average in 2012 was 2,13%(±0,009), in 2013 2,91%(±0,010) and in 2014 1,84%(±0,008), inferior to 5%, which is acceptable; the mean age patients was 59,3 years old being 50,7 female and 82,8% white skin. Pneumonia was the diagnosis that took patients to hospital admission and 49,6% of the patients had hypertension. 436 phlebitis occurred with emphasis to one patient that had five phlebitis within 30 days; the phlebitis classification with higher occurrence was of degree 2 (45,4%), the most used caliber catheter was 22 G (29,7%); the most used for vein puncture access was the left upper limb (53,4%); the professional who most performed vein puncture were assistants/technical nursing (32,6%). According to the medications used during phlebitis moments, 96,2% were antibiotics; the time spent for the catheter since its insertion until the moment that the phlebitis appeared was 48 hours (31,1); 20,9% of notified phlebitis were from other punctures applied in other services, which were not in the institution that the study was conducted. It occurred variation in the collected exam results before and after the phlebitis occurrence like hemoglobin, white blood cells, Reactive Protein C; therefore, only the two last ones presented significant statistically results (p=0,0095 and p=0,0001 respectively). It is observed significant statistically results (p= 0,0172) in association with phlebitis of degree 2 with the catheter of caliber number 22 G. Conclusion: the study adds knowledge to the area of nursing and it is the first approaching theme that has happened in the hospital institution. Despite the number of phlebitis being smaller than the acceptable by the literature, it is necessary effort and dedication to this index diminish even more, because of that it directly influences in the patient´s assistance quality and the patient´s security

Background: Pulmonary embolism (PE) accounts for almost 40% of perioperative deaths after bariatric surgery. Placement of prophylactic inferior vena cava (IVC) filter before bariatric surgery to improve outcomes has shown varied results. We performed a meta-analysis to evaluate postoperative outcomes associated with the preoperative placement of IVC filters in these patients. Methods: A systematic review was conducted by three investigators independently in PubMed, EMBASE, the Web of Science and Scopus until February 28, 2013. Our search was restricted to studies in adult patients undergoing bariatric surgery with and without IVC filters. Primary outcomes were postoperative deep vein thrombosis (DVT), pulmonary embolism (PE), and postoperative mortality. Meta-analysis used random effects models to account for heterogeneity, and Sidik-Jonkman method to account for scarcity of outcomes and studies. Associations are shown as Relative Risks (RR) and 95% Confidence Intervals (CI). Results: Seven observational studies were identified (n=102,767), with weighted average incidences of DVT (0.9%), PE (1.6%), and mortality (1.0%) for a follow-up ranging from 3 weeks to 3 months. Use of IVC filters was associated with an approximately 3-fold higher risk of DVT and death that was nominally significant for the former outcome, but not the latter (RR 2.81, 95%CI 1.33-5.97, p=0.007; and RR 3.27, 95% CI 0.78-13.64, p=0.1, respectively); there was no difference in the risk of PE (RR 1.02, 95%CI 0.31-3.77, p=0.9). Moderate to high heterogeneity of effects was noted across studies. Conclusions: Placement of IVC filter before bariatric surgery is associated with higher risk of postoperative DVT and mortality. A similar risk of PE in patients with and without IVC filter placement cannot exclude a benefit, given the potential large imbalance in risk at baseline. Randomized trials are needed before IVC placement can be recommended. / Revisión por pares

Diana.sobieraj@hhchealth.org / Objective To systematically review the literature and to quantitatively evaluate the efficacy and safety of extended pharmacologic treatment of venous thromboembolism (VTE) through network meta-analysis (NMA). Methods A systematic literature search (MEDLINE, Embase, Cochrane CENTRAL, through September 2014) and searching of reference lists of included studies and relevant reviews was conducted to identify randomized controlled trials of patients who completed initial anticoagulant treatment for VTE and then randomized for the extension study; compared extension of anticoagulant treatment to placebo or active control; and reported at least one outcome of interest (VTE or a composite of major bleeding or clinically relevant non-major bleeding). A random-effects Frequentist approach to NMA was used to calculate relative risks with 95% confidence intervals. Results Ten trials (n=11,079) were included. Risk of bias (assessed with the Cochrane tool) was low in most domains assessed across the included trials. Apixaban (2.5mg and 5mg), dabigatran, rivaroxaban, idraparinux and vitamin K antagonists (VKA) each significantly reduced the risk of VTE recurrence compared to placebo, ranging from a 73% reduction with idraparinux to 86% with VKAs. With exception of idraparinux, all active therapies significantly reduced VTE recurrence risk versus aspirin, ranging from a 73% reduction with either apixaban 2.5mg or rivaroxaban to 80% with VKAs. Apixaban and aspirin were the only therapies that did not increase composite bleeding risk significantly compared to placebo. All active therapies except aspirin increased risk of composite bleeding by 2 to 4-fold compared to apixaban 2.5mg, with no difference found between the two apixaban doses. Conclusion Extended treatment of VTE is a reasonable approach to provide continued protection from VTE recurrence although bleeding risk is variable across therapeutic options. Our results indicate that apixaban, dabigatran, rivaroxaban, idraparinux and VKAs all reduced VTE recurrence when compared to placebo. Apixaban appears to have a more favorable safety profile compared to other therapies. / Revisión por pares

Os acessos venosos são indispensáveis para assistência do paciente em situação crítica. O cateter venoso central (CVC) é um acesso que viabiliza a terapêutica dessa clientela, mas o seu uso pode levar à infecções. Estas infecções ocasionam maior permanência hospitalar, elevam os custos totais das instituições e aumentam a morbidade e a mortalidade do paciente. O uso de curativos como cobertura do sítio de saída do CVC é eficaz na prevenção das infecções relacionadas a estes cateteres, em particular, o uso de curativos impregnados com antissépticos como o curativo gel de clorexidina. Este estudo teve como objetivo comparar a efetividade do curativo gel de clorexidina com a do filme transparente de poliuretano na prevenção da colonização do cateter venoso central em pacientes adultos críticos. Trata-se de estudo experimental, do tipo ensaio clínico randomizado, com tratamentos em paralelo, prospectivo e monocêntrico, realizado de acordo com as recomendações do Consolidated Standards of Reporting Trials (CONSORT). O estudo foi realizado na Unidade de Terapia Intensiva e na Unidade Coronariana de um hospital de ensino do interior do Estado de São Paulo. Participaram do estudo 102 indivíduos hospitalizados nestes locais, divididos aleatoriamente em dois grupos: grupo intervenção, no qual o tipo de cobertura utilizada foi o curativo de gel de clorexidina e grupo controle, que utilizou como cobertura o filme transparente de poliuretano. O desfecho primário mensurado foi a colonização do cateter e os desfechos secundários foram a infecção clínica do sítio de saída, a infecção microbiológica do sítio de saída e a infecção da corrente sanguínea relacionada ao cateter. Para a coleta de dados foi elaborado um instrumento, e este validado quanto ao seu conteúdo e forma por 13 enfermeiros pertencentes aos locais do estudo. Estes profissionais foram treinados para a realização dos curativos e coleta das pontas dos cateteres centrais, swabs dos sítios de saída e hemoculturas. Análises descritivas foram usadas para todas as variáveis do estudo. O teste Exato de Fisher foi utilizado para comparar as proporções de cada desfecho nos grupos de intervenção e controle, e a regressão logística para explorar se a colonização no CVC poderia ser associada com o tempo de uso do cateter e com o Acute Physiology and Chronic Health Evaluation II (APACHE II) dos pacientes do estudo. De acordo com os resultados não houve diferença estatisticamente significante entre a colonização nos dois grupos (p valor = 1.00), para a infecção microbiológica do sítio de saída (p valor = 0.08), para a infecção clínica do sítio de saída (p valor = 0.77) e para as infecções da corrente sanguínea relacionadas ao cateter (p valor = 1,00). Conclui-se que o presente estudo pode contribuir para que as unidades de saúde tenham subsídios para realizar a escolha do tipo de curativo baseado em suas necessidades institucionais e no desenvolvimento de protocolos relacionados à medidas de inserção e manutenção do cateter, bem como medidas educativas permanentes / The venous access is essential to patient care in critical condition. The central venous catheter (CVC) is an access point that allows the treatment of patients, but its use can lead to infections. These infections increase the period of hospital permanence, the total costs of institutions and the patients\' morbidity and mortality. The use of dressings for coverage of the CVC exit-site is effective in preventing infections related to these catheters, in particular, the use of dressings impregnated with antiseptics such as chlorhexidine gel. This study aimed to compare the effectiveness of chlorhexidine gel dressing with the transparent polyurethane film in preventing colonization of central venous catheter in critical adult patients. This randomized experimental study with parallel treatment, prospective and monocentric, which is conducted according to the Consolidated Standards of Reporting Trials (CONSORT) guidelines. The research was performed in an Intensive Care Unit and in a Coronary Care of a teaching hospital in the interior of the State of São Paulo. The study included 102 patients hospitalized in these units, randomly divided into two groups: the intervention group, which used chlorhexidine gel dressing and the control group, which used the transparent polyurethane film dressing. The primary outcome measured was the colonization of the catheter and the secondary outcomes were the clinical infection and microbial infection of the exit-site and the catheter-related bloodstream infection. Data were collected through an instrument developed and validated in terms of content and form by 13 nurses of the Units where the study was performed. These professionals were trained to use the dressings and to collect the tips of central catheters, swabs of the exit-site and blood cultures. Descriptive statistics were used for all study variables. The Fisher\'s exact test was used to compare the proportions of each outcome in the groups of intervention and control. The logistic regression analysis was used to explore if the colonization of the CVC could be associated with the catheter usage time and the Acute Physiology and Chronic Health Evaluation II (APACHE II) of the research\'s participants. According to the results there was no statistically significant difference between colonization in both groups (p value=1:00), for exit-site microbial infection (p value=0:08), for exit- site clinical infection (p value = 0.77) and for catheter-related bloodstream infection (p-value=1.00). The results of this study may contribute in providing subsidies to health units to make the choice in the use of the type of dressing based on their institutional needs and in the development of protocols related to integration measures and maintenance of the catheter, as well as permanent educational measures

Malignancy is associated with a hypercoagulable state manifested clinically by an increased incidence of venous thromboembolism (VTE). Colorectal cancer (CRC) patients who develop VTE have reduced survival. This increased mortality extends beyond the acute VTE event, suggesting that VTE is associated with aggressive tumour biology. Tissue factor (TF) and other clotting factors have been implicated in this process. However, the significance of clotting factors in the tumour microenvironment (TME) remains unknown. The aim of this thesis is to i) determine if a procoagulant TME is a biomarker for poor prognosis and VTE in patients undergoing resectional surgery for CRC and ii) determine the effect of TF, thrombin and FXa on proliferation and migration in vitro in CRC and if their inhibitors have potential as anticancer therapies. In the in vitro studies, epithelial expression of TF had a modest effect on proliferation and migration when quantified using the PrestoBlue proliferation and transwell migration assays. Exogenous TF, FXa and thrombin all increased migration in DLD-1 wild type cells. In addition, exogenous thrombin increased proliferation amongst SW620 wild type cells. This suggests that coagulation factors from the TME, rather than epithelial expression, may influence tumour biology. Moreover, dabigatran, a direct thrombin inhibitor, abrogated the pro-proliferative effects of thrombin, which highlights its potential role as an anticancer therapy. In a multicentre, prospective cohort study of 159 CRC patients undergoing resectional surgery, rates of duplex screen detected deep vein thrombosis (DVT) were correlated to plasma and tumour markers of hypercoagulability. TF is upregulated in the stroma of cancer compared to normal tissue. However, stromal TF expression decreased in more advanced (T4) tumours. This suggests that a procoagulant TME has a role in early tumourigenesis. In total, 5.4%, 7.0% and 9.1% of patients had an asymptomatic DVT pre- operatively, at six weeks post-surgery and after the commencement of adjuvant chemotherapy respectively. The development of a post-operative complication was a risk factor for DVT, whilst locally advanced tumours resulted in a prolonged hypercoagulable state i.e. raised D-dimer at six weeks. This highlights a possible role for pre- and post- operative screening duplex ultrasonography and super-extended VTE prophylaxis in selected patients. In conclusion, this thesis establishes a role for exogenous coagulation factors in promoting tumour biology in CRC. VTE is more common amongst patients undergoing resectional surgery for CRC than previously estimated. The utility of tumour and plasma hypercoagulabilty as biomarkers for survival in CRC will be further analysed when long term follow-up data is available.

Técnicas cirúrgicas para realização de craniotomias são descritas na literatura há mais de cinqüenta anos. Contudo, a sua realização ainda é limitada, muitas vezes pela ausência de diagnóstico conclusivo. Com o advento de métodos não invasivos como a tomografia computadorizada, a especificidade quanto ao tipo e localização da lesão tornou-se possível. As principais abordagens cranianas são as técnicas de craniotomia transfrontal que promovem acesso ao cérebro. Os principais pontos de referência para a realização da técnica são os seios venosos da dura mater. Este estudo visou analisar o acesso cirúrgico em relação ao seio venoso sagital dorsal, bem como compará-lo nos diferentes tipos de crânio: braquicefálico e mesaticefálico. Foram utilizados 16 crânios provenientes de 8 cães da raça boxer, 5 cães sem raça definida, 1 rotweiller, 1 labrador e 1 pinscher. O trajeto do seio venoso sagital superior foi estudado pelo método de injeção de solução de látex com pigmento colorido e sulfato de bário. A relação do SVSD foi estudada através de análise das imagens obtidas pela tomografia computadorizada. Os crânios braquicefálicos apresentaram índice cefálico médio igual à 91,24 e índice crânio fácil igual à 2,89; enquanto nos crânio mesaticefálicos obtivemos os valores médios de 79,77 e 1,92 para os índices cefálico e crânio facial respectivamente. O trajeto do seio venoso sagital dorsal foi delimitado, tendo início na porção média do arco zigomático e término ao nível do osso occipital nos dois grupos de crânios. Em relação às mensurações do seio venoso relativas à calota craniana obtivemos os valores médios da área = 7,35+-2,51; D1 = 6,65+-2,27; D2 = 16,17+-4,08; D3 = 15,75-+5,09; D4 = 18,33+-5,25 e D5 = 18,04+-5,87 no grupo mesaticefálico e os valores médios da área = 10,18+-4,69; D1 = 11,84+-2,35; D2 = 19,57+-2,61; D3 = 17,88+-2,31; D4 = 25,32+-5,68 e D5 = 24,84=-4,40 no grupo braquicefálico. Os valores referentes á área, D4 e D5 apresentaram diferença estatística (P<0,05), que denota diferença no formato da calota craniana entre os dois grupos, assim consequentemente diferença na medida citada como margem de segurança para a realização da abordagem cirúrgica do cérebro. / The surgical approaches for craniotomy are describe since the fifties. However, this realization is limited, many times for the absence conclusive diagnosis. The non invasive methods like computed tomography, the lesion locatization and type are easily made. The most important surgical approach is transfrontal craniotomy which promoves brain access. The principal landmarks to the surgery are the dura mater venous sinus. The objetive of this study was to analise the surgical access relation to the dorsal sagittal sinus and to compare with the different skull type: mesaticephalic and braquicephalic. Sixteen skulls from 8 Boxer dogs, 5 Mongrel dogs, 1 Rottweiler, 1 Labrador and 1 Pinscher. The sinus path was studied by solution of bario and látex whith coloured pigment injection. The dorsal sagittal sinus relation was studied by CT image analysis. The braquicephalic skulls showed cephalic index = 91,24 and cranio facial index = 2,89, and the mesaticephalic skulls presents 79,77 and 1,92 for cephalic and crânio facial index. The dorsal sagittal sinus path was delimited, and the medium of the zigomatic arc is this begging and the occipital bone the final, in both skull types. The venous sinus mensurations interface to the skull are: area = 7,35+/-2,51; D1 = 6,65+-2,27; D2 = 16,17+-4,08; D3 = 15,75-+5,09; D4 = 18,33+-5,25 e D5 = 18,04+-5,87 in mesaticephalic dogs and the medium mensurations da area = 10,18+-4,69; D1 = 11,84+-2,35; D2 = 19,57+-2,61; D3 = 17,88+-2,31; D4 = 25,32+-5,68 e D5 = 24,84=-4,40 in braquicephalic group. The área, D4 and D5 mensurations presents statistic difference (P<0,05), which show the skull form difference betwen the two groups, and the edge for the surgical approach to the brain.