Browsing by Author "Machado, C"
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- Blood Pressure Variability in Acute Ischemic Stroke: The Role of Early RecanalizationPublication . Martins, AI; Sargento-Freitas, J; Jesus-Ribeiro, J; Correia, I; Cardoso, L; Gomes, JP; Gonçalves, M; Costa, R; Silva, F; Galego, O; Nunes, C; Beato-Coelho, J; Varela, R; Machado, C; Rodrigues, B; Santo, GC; Cunha, LWe performed a retrospective study with the aim of investigating the association between blood pressure (BP) variability in the first 24 h after ischemic stroke and functional outcome, regarding arterial recanalization status. A total of 674 patients diagnosed with acute stroke and treated with revascularization therapies were enrolled. Systolic and diastolic BP values of the first 24 h after stroke were collected and their variation quantified through standard deviation. Recanalization state was evaluated at 6 h and clinical outcome at 3 months was assessed by modified Rankin Scale. In multivariate analyses systolic BP variability in the first 24 h post-stroke showed an association with 3 months clinical outcome in the whole population and non-recanalyzed patients. In recanalyzed patients, BP variability did not show a significant association with functional outcome.
- Endothelial Progenitor Cells influence acute and subacute stroke hemodynamicsPublication . Sargento-Freitas, J; Aday, S; Nunes, C; Cordeiro, M; Gouveia, A; Silva, F; Machado, C; Rodrigues, B; Santo, GC; Ferreira, C; Castelo-Branco, M; Ferreira, L; Cunha, LBACKGROUND: Endothelial Progenitor Cells (EPCs) are a circulating stem cell population with in vivo capacity of promoting angiogenesis after ischemic events. Despite the promising preclinical data, their potential integration with reperfusion therapies and hemodynamic evolution of stroke patients is still unknown. Our aim was to determine the association of EPCs with acute, subacute and chronic hemodynamic features. METHODS: In this prospective study, we included consecutive patients with ages between 18 and 80years and non-lacunar ischemic stroke within the territory of a middle cerebral artery. All patients were subject to hemodynamic evaluation by ultrasound at baseline, seven days and three months. We quantified cerebral blood flow (CBF) and assessed early recanalization and collateral flow. Hemorrhagic transformation was graded in Magnetic Resonance imaging performed at seven days. EPCs were isolated from peripheral venous blood collected in the first 24h and seven days, counted and submitted to functional in vitro tests. RESULTS: We included 45 patients with a median age of 70±10years. The angiogenic and migratory capacities of EPCs were associated with increased collateral flow in the acute stage and day seven CBF, without statistically significant associations with recanalization nor haemorrhagic transformation. The number of EPCs was not associated with any hemodynamic variable. CONCLUSIONS: The functional properties of EPCs are associated with acute and subacute stroke hemodynamics, with no effect on haemorrhagic transformation.
- Fístulas da tenda do cerebelo: diagnóstico e tratamentoPublication . Machado, E; Santos, N; Carvalho, S; Freitas, P; Filho, T; Machado, C; Martins, FAmong the 17 intracranial dural fistulae treated in the Department of Neuroradiology of the University Hospital of Coimbra (17 patients, 28 embolizations) between 19/10/98 and 20/11/2000, 4 cases (23%) were located on the tentorium cerebelli. Three patients were men aged 45, 53 and 56 years old. The remaining patient was an 85-year-old woman. All 4 patients were treated by embolization. One underwent post embolization surgical interruption of the draining vein. The authors analyse clinical presentation, complementary tests, therapy and outcome.
- Kidney transplantation and posttransplantation diabetes: nutritional evaluationPublication . Loureiro, H; Silva, RS; Machado, C; Bastos, M; Baptista, C; Alves, R; Mota, A; Furtado, AL; Carvalheiro, M; Saldanha, MH
- Pathophysiology of Blood–Brain Barrier Permeability Throughout the Different Stages of Ischemic Stroke and Its Implication on Hemorrhagic Transformation and RecoveryPublication . Bernardo-Castro, S; Sousa, JA; Brás, A; Cecília, C; Rodrigues, B; Almendra, L; Machado, C; Santo, G; Silva, F; Ferreira, L; Santana, I; Sargento-Freitas, JThe blood-brain barrier (BBB) is a dynamic interface responsible for maintaining the central nervous system homeostasis. Its unique characteristics allow protecting the brain from unwanted compounds, but its impairment is involved in a vast number of pathological conditions. Disruption of the BBB and increase in its permeability are key in the development of several neurological diseases and have been extensively studied in stroke. Ischemic stroke is the most prevalent type of stroke and is characterized by a myriad of pathological events triggered by an arterial occlusion that can eventually lead to fatal outcomes such as hemorrhagic transformation (HT). BBB permeability seems to follow a multiphasic pattern throughout the different stroke stages that have been associated with distinct biological substrates. In the hyperacute stage, sudden hypoxia damages the BBB, leading to cytotoxic edema and increased permeability; in the acute stage, the neuroinflammatory response aggravates the BBB injury, leading to higher permeability and a consequent risk of HT that can be motivated by reperfusion therapy; in the subacute stage (1-3 weeks), repair mechanisms take place, especially neoangiogenesis. Immature vessels show leaky BBB, but this permeability has been associated with improved clinical recovery. In the chronic stage (>6 weeks), an increase of BBB restoration factors leads the barrier to start decreasing its permeability. Nonetheless, permeability will persist to some degree several weeks after injury. Understanding the mechanisms behind BBB dysregulation and HT pathophysiology could potentially help guide acute stroke care decisions and the development of new therapeutic targets; however, effective translation into clinical practice is still lacking. In this review, we will address the different pathological and physiological repair mechanisms involved in BBB permeability through the different stages of ischemic stroke and their role in the development of HT and stroke recovery.
- Recurrence in intracranial atherosclerotic disease: a stenosis-based analysisPublication . Gouveia, A; Sargento-Freitas, J; Penetra, J; Silva, F; Machado, C; Cordeiro, G; Cunha, LBACKGROUND: Intracranial atherosclerotic disease is a common cause of stroke; its incidence and prevalence vary widely by ethnicity. The aim of our study was to analyze the recurrence rate of cerebrovascular events in patients with symptomatic and asymptomatic intracranial stenosis (IS). METHODS: We conducted a historical cohort study including all patients admitted in our hospital for stroke or transient ischemic attack (TIA) during 2011 and 2012 with information on intracranial circulation (ultrasonography and/or computed tomography angiography). We identified patients with symptomatic and asymptomatic IS and studied the recurrence of cerebrovascular events (TIA or ischemic stroke within the territory of the stenosis) for a minimum follow-up period of 6 months after the diagnosis of IS. For the recurrence rate estimation, patients with other potentially embolic diseases (in cervical arteries or heart) were excluded. We calculated the rate of recurrence of cerebrovascular events and performed Kaplan-Meier survival curves for symptomatic and asymptomatic IS. RESULTS: We investigated 1302 patients, mean age was 72.41 years (standard deviation 12.75). We identified 218 IS in 158 patients, 77 were symptomatic and 141 were asymptomatic. The recurrence rate of cerebrovascular events was 12.32 per 100 patient-years, with a mean time to recurrence of 1.73 months for symptomatic intracranial stenosis (SIS) and .88 per 100 patient-years for asymptomatic IS (P < .001). CONCLUSIONS: These results indicate a high risk of early recurrence of stroke in the territory of a SIS, highlighting the importance of its early diagnosis and aggressive treatment.