963 resultados para Microvascular Angina
Resumo:
Angiogenesis and lymphangiogenesis are changes that occur due to gingival inflammation caused by microorganisms present in the biofilm, as well as the migration of immune cells and secretion of mediators in the aggressed site. This study aimed to research angiogenesis and lymphangiogenesis in 90 specimens of clinically healthy, with gingivitis and chronic periodontitis gingival tissue biopsies. The histological sections were evaluated by hematoxylin and eosin and the immunohistochemical technique through immunostaining for CD34 and podoplanin. To evaluate the angiogenic and lymphangiogenic indexes we performed a microvessel counting technique. The results showed that there is a correlation between the indexes (p = 0.030), however, we observed that periodontitis showed less lymphatic vessels than clinically healthy gingival tissue (p = 0.016). Podoplanin showed positive staining in the basal layers of the epithelium, and we observed a relationship between immunostaining intensity and the intensity of inflammatory infiltrate, with more intense staining in the presence of severe inflammatory infiltrate (p = 0.033). For this study, we concluded that there are fewer blood vessels in periodontitis compared with clinically healthy gingiva. The signaling present in the inflammatory process and the actual role of gingival blood and lymphatic vasculature are not fully understood, with further studies on angiogenesis and lymphangiogenesis being suggested.
Resumo:
Angiogenesis and lymphangiogenesis are changes that occur due to gingival inflammation caused by microorganisms present in the biofilm, as well as the migration of immune cells and secretion of mediators in the aggressed site. This study aimed to research angiogenesis and lymphangiogenesis in 90 specimens of clinically healthy, with gingivitis and chronic periodontitis gingival tissue biopsies. The histological sections were evaluated by hematoxylin and eosin and the immunohistochemical technique through immunostaining for CD34 and podoplanin. To evaluate the angiogenic and lymphangiogenic indexes we performed a microvessel counting technique. The results showed that there is a correlation between the indexes (p = 0.030), however, we observed that periodontitis showed less lymphatic vessels than clinically healthy gingival tissue (p = 0.016). Podoplanin showed positive staining in the basal layers of the epithelium, and we observed a relationship between immunostaining intensity and the intensity of inflammatory infiltrate, with more intense staining in the presence of severe inflammatory infiltrate (p = 0.033). For this study, we concluded that there are fewer blood vessels in periodontitis compared with clinically healthy gingiva. The signaling present in the inflammatory process and the actual role of gingival blood and lymphatic vasculature are not fully understood, with further studies on angiogenesis and lymphangiogenesis being suggested.
Resumo:
Background: Workplace demographics are changing in many European countries with a higher proportion of older workers in employment. Research has shown that there is an association between job strain and cardiovascular disease, but this relationship is unclear for the older worker. Aims: To investigate the association between job strain and a coronary event comparing younger and older male workers. Methods: Cases with a first-time coronary event were recruited from four coronary/intensive care units (1999-2001). Matched controls were recruited from the case's general practitioner surgery. Physical measurements were taken and self-administered questionnaires completed with questions on job characteristics, job demands and control. Unconditional logistic regression was carried out adjusting for classical cardiovascular risk factors. Results: There were 227 cases and 277 matched controls. Age stratified analyses showed a clear difference between younger (= 50 years) workers with regard to the exposure of job strain (job demands and control) and the association between these factors and cardiovascular disease. Older workers who had a coronary event were four times as likely to have high job strain [OR = 4.09 (1.29-13.02)] and more likely to report low job control [ OR = 0.83 (0.72-0.95)]. Conclusions: Job control emerged as a potential protective factor for heart disease and this evidence was stronger in the older male worker. Nevertheless, they were significantly more likely to have job strain. These results suggest that older workers may be more susceptible to job strain.
Resumo:
Tumor angiogenesis is critical to tumor growth and metastasis, yet much is unknown about the role vascular cells play in the tumor microenvironment. A major outstanding challenge associated with studying tumor angiogenesis is that existing preclinical models are limited in their recapitulation of in vivo cellular organization in 3D. This disparity highlights the need for better approaches to study the dynamic interplay of relevant cells and signaling molecules as they are organized in the tumor microenvironment. In this thesis, we combined 3D culture of lung adenocarcinoma cells with adjacent 3D microvascular cell culture in 2-layer cell-adhesive, proteolytically-degradable poly(ethylene glycol) (PEG)-based hydrogels to study tumor angiogenesis and the impacts of neovascularization on tumor cell behavior.
In initial studies, 344SQ cells, a highly metastatic, murine lung adenocarcinoma cell line, were characterized alone in 3D in PEG hydrogels. 344SQ cells formed spheroids in 3D culture and secreted proangiogenic growth factors into the conditioned media that significantly increased with exposure to transforming growth factor beta 1 (TGF-β1), a potent tumor progression-promoting factor. Vascular cells alone in hydrogels formed tubule networks with localized activated TGF-β1. To study cancer cell-vascular cell interactions, the engineered 2-layer tumor angiogenesis model with 344SQ and vascular cell layers was employed. Large, invasive 344SQ clusters developed at the interface between the layers, and were not evident further from the interface or in control hydrogels without vascular cells. A modified model with spatially restricted 344SQ and vascular cell layers confirmed that observed 344SQ cluster morphological changes required close proximity to vascular cells. Additionally, TGF-β1 inhibition blocked endothelial cell-driven 344SQ migration.
Two other lung adenocarcinoma cell lines were also explored in the tumor angiogenesis model: primary tumor-derived metastasis-incompetent, murine 393P cells and primary tumor-derived metastasis-capable human A549 cells. These lung cancer cells also formed spheroids in 3D culture and secreted proangiogenic growth factors into the conditioned media. Epithelial morphogenesis varied for the primary tumor-derived cell lines compared to 344SQ cells, with far less epithelial organization present in A549 spheroids. Additionally, 344SQ cells secreted the highest concentration of two of the three angiogenic growth factors assessed. This finding correlated to 344SQ exhibiting the most pronounced morphological response in the tumor angiogenesis model compared to the 393P and A549 cell lines.
Overall, this dissertation demonstrates the development of a novel 3D tumor angiogenesis model that was used to study vascular cell-cancer cell interactions in lung adenocarcinoma cell lines with varying metastatic capacities. Findings in this thesis have helped to elucidate the role of vascular cells in tumor progression and have identified differences in cancer cell behavior in vitro that correlate to metastatic capacity, thus highlighting the usefulness of this model platform for future discovery of novel tumor angiogenesis and tumor progression-promoting targets.
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Aims: To describe trends in the incidence of visual impairment and blindness due to diabetic retinopathy among adults aged 18–69 years in Ireland between 2004 and 2013. Methods: Data on visual impairment due to diabetic retinopathy in adults aged 18–69 years or over who are registered with the National Council for the Blind of Ireland, (2004–2013) were analysed. Annual incidence rates were calculated for the adult population and the population with diagnosed diabetes. Poisson regression was used to test for changes in rates over time. The relative, attributable and population risk of blindness and visual impairment due to diabetic retinopathy were calculated for 2013. Results: Over the decade, the prevalence of diagnosed diabetes increased from 2.1% to 3.6%. Among people with diagnosed diabetes, the incidence of visual impairment due to diabetic retinopathy increased from 6.4 (95% CI 2.4–13.9) per 100,000 in 2004 to 11.7 (95% CI 5.9–21.0) per 100,000 in 2013. The incidence of blindness due to diabetic retinopathy varied from 31.9 per 100,000 (95% CI 21.6–45.7) in 2004 to 14.9 per 100,000 (95% CI 8.2–25.1) in 2013. Conclusions: Our findings indicate the need for increased attention to preventive measures for microvascular complications among adults with diabetes in Ireland. Retinopathy screening has been standardised in Ireland, these findings provide useful baseline statistics to monitor the impact of this population-based screening programme.
Resumo:
Background: Accurate estimates of the burden of diabetes are essential for future planning and evaluation of services. In Ireland, there is no diabetes register and prevalence estimates vary. The aim of this review was to systematically identify and review studies reporting the prevalence of diabetes and complications among adults in Ireland between 1998 and 2015 and to examine trends in prevalence over time. Methods: A systematic literature search was carried out using PubMed and Embase. Diabetes prevalence estimates were pooled by random-effects meta-analysis. Poisson regression was carried out using data from four nationally representative studies to calculate prevalence rates of doctor diagnosed diabetes between 1998 and 2015 and was also used to assess whether the rate of doctor diagnosed diabetes changed over time. Results: Fifteen studies (eight diabetes prevalence and seven complication prevalence) were eligible for inclusion. In adults aged 18 years and over, the national prevalence of doctor diagnosed diabetes significantly increased from 2.2 % in 1998 to 5.2 % in 2015 (p trend ≤ 0.001). The prevalence of diabetes complications ranged widely depending on study population and methodology used (6.5–25.2 % retinopathy; 3.2–32.0 % neuropathy; 2.5-5.2 % nephropathy). Conclusions: Between 1998 and 2015, there was a significant increase in the prevalence of doctor diagnosed diabetes among adults in Ireland. Trends in microvascular and macrovascular complications prevalence could not be examined due to heterogeneity between studies and the limited availability of data. Reliable baseline data are needed to monitor improvements in care over time at a national level. A comprehensive national diabetes register is urgently needed in Ireland.
Resumo:
Cerebral malaria is characterized by cytoadhesion of Plasmodium falciparum–infected red blood cells (Pf-iRBCs) to endothelial cells in the brain, disruption of the blood-brain barrier, and cerebral microhemorrhages. No available antimalarial drugs specifically target the endothelial disruptions underlying this complication, which is responsible for the majority of malaria-associated deaths. Here, we have demonstrated that ruptured Pf-iRBCs induce activation of β-catenin, leading to disruption of inter–endothelial cell junctions in human brain microvascular endothelial cells (HBMECs). Inhibition of β-catenin–induced TCF/LEF transcription in the nucleus of HBMECs prevented the disruption of endothelial junctions, confirming that β-catenin is a key mediator of P. falciparum adverse effects on endothelial integrity. Blockade of the angiotensin II type 1 receptor (AT1) or stimulation of the type 2 receptor (AT2) abrogated Pf-iRBC–induced activation of β-catenin and prevented the disruption of HBMEC monolayers. In a mouse model of cerebral malaria, modulation of angiotensin II receptors produced similar effects, leading to protection against cerebral malaria, reduced cerebral hemorrhages, and increased survival. In contrast, AT2-deficient mice were more susceptible to cerebral malaria. The interrelation of the β-catenin and the angiotensin II signaling pathways opens immediate host-targeted therapeutic possibilities for cerebral malaria and other diseases in which brain endothelial integrity is compromised.
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Background: Individuals with chronic obstructive pulmonary disease (COPD) have higher than normal ventilatory equivalents for carbon dioxide (VE/VCO2) during exercise. There is growing evidence that emphysema on thoracic computed tomography (CT) scans is associated with poor exercise capacity in COPD patients with only mild-to-moderate airflow obstruction. We hypothesized that emphysema is an underlying cause of microvascular dysfunction and ventilatory inefficiency, which in turn contributes to reduced exercise capacity. We expected ventilatory inefficiency to be associated with a) the extent of emphysema; b) lower diffusing capacity for carbon monoxide; c) a reduced pulmonary blood flow response to exercise; and d) reduced exercise capacity. Methods: In a cross-sectional study, 19 subjects with mild-to-moderate COPD (mean ± SD FEV1= 82 ± 13% predicted, 12 GOLD grade 1) and 26 age-, sex-, and activity-matched controls underwent a ramp-incremental symptom-limited exercise test on a cycle ergometer. Ventilatory inefficiency was assessed by the minimum VE/VCO2 value (nadir). A subset of subjects also completed repeated constant work rate exercise bouts with non-invasive measurements of pulmonary blood flow. Emphysema was quantified as the percentage of attenuation areas below -950 Housefield Units on CT scans. An electronic scoresheet was used to keep track of emphysema sub-types. Results: COPD subjects typically had centrilobular emphysema (76.8 ± 10.1% of total emphysema) in the upper lobes (upper/lower lobe ratio= 0.82 ± 0.04). They had lower peak oxygen uptake (VO2), higher VE/VCO2 nadir and greater dyspnea scores than controls (p<0.05). Lower peak O2 and worse dyspnea were found in COPD subjects with VE/VCO2 nadirs ≥ 30. COPD subjects had blunted increases in pulmonary blood flow from rest to iso-VO2 exercise (p<0.05). Higher VE/VCO2 nadir in COPD subjects correlated with emphysema severity (r= 0.63), which in turn correlated with reduced lung diffusing capacity (r= -0.72) and blunted changes in pulmonary blood flow from rest to exercise (r= -0.69) (p<0.01). Conclusions: Ventilation “wasted” in emphysematous areas is associated with reduced exercise ventilatory efficiency in mild-to-moderate COPD. Exercise ventilatory inefficiency links structure (emphysema) and function (gas transfer) to a key clinical outcome (reduced exercise capacity) in COPD patients with modest spirometric abnormalities.
Resumo:
Lipoprotein-associated phospholipase A2 (Lp-PLA2) hydrolyses oxidized low-density lipoproteins into proinflammatory products, which can have detrimental effects on vascular function. As a specific inhibitor of Lp-PLA2, darapladib has been shown to be protective against atherogenesis and vascular leakage in diabetic and hypercholesterolemic animal models. This study has investigated whether Lp-PLA2 and its major enzymatic product, lysophosphatidylcholine (LPC), are involved in blood-retinal barrier (BRB) damage during diabetic retinopathy. We assessed BRB protection in diabetic rats through use of species-specific analogs of darapladib. Systemic Lp-PLA2 inhibition using SB-435495 at 10 mg/kg (i.p.) effectively suppressed BRB breakdown in streptozotocin-diabetic Brown Norway rats. This inhibitory effect was comparable to intravitreal VEGF neutralization, and the protection against BRB dysfunction was additive when both targets were inhibited simultaneously. Mechanistic studies in primary brain and retinal microvascular endothelial cells, as well as occluded rat pial microvessels, showed that luminal but not abluminal LPC potently induced permeability, and that this required signaling by the VEGF receptor 2 (VEGFR2). Taken together, this study demonstrates that Lp-PLA2 inhibition can effectively prevent diabetes-mediated BRB dysfunction and that LPC impacts on the retinal vascular endothelium to induce vasopermeability via VEGFR2. Thus, Lp-PLA2 may be a useful therapeutic target for patients with diabetic macular edema (DME), perhaps in combination with currently administered anti-VEGF agents.
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Le compartiment microvasculaire est une cible importante du stress oxydant qui est un facteur majeur de la dysfonction endothéliale, notamment au cours d’exposition aux rayonnements ionisants. L’altération de l’endothélium induite par le stress oxydant est impliquée dans la toxicité radio-induite des tissus sains. Limiter les dysfonctions endothéliales est donc un enjeu important des traitements radiothérapeutiques actuels. Cet objectif nécessite une meilleure caractérisation de la signalisation du stress oxydant dans les cellules endothéliales. La voie p38 MAPK est incontournable dans la réponse au stress oxydant mais reste encore insuffisamment caractérisée. Par une approche protéomique, nous avons identifié la nucléophosmine (NPM) comme nouveau partenaire de p38 dans le cytoplasme des cellules endothéliales. La phosphatase PP2a est aussi associée à ce complexe NPM/p38. Nos travaux montrent que le stress oxydant (H2O2, 500μM) régule la déphosphorylation de NPM via PP2a, entraine sa dissociation rapide du complexe et favorise sa translocation vers le noyau. De plus, nous montrons que la présence de NPM déphosphorylée au noyau altère la réponse des cellules aux dommages à l’ADN induits par le stress oxydant. Le céramide sphingolipide membranaire est également un facteur important des voies de stress, particulièrement dans les cellules endothéliales. Notre étude aborde donc l’implication de ce sphingolipide dans la régulation de la voie NPM/p38. Une meilleure caractérisation de la voie p38 et de ses acteurs permettra d’identifier de potentielles cibles afin de limiter les dysfonctions endothéliales et leurs conséquences délétères sur les tissus environnants.
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Understanding the dynamics of blood cells is a crucial element to discover biological mechanisms, to develop new efficient drugs, design sophisticated microfluidic devices, for diagnostics. In this work, we focus on the dynamics of red blood cells in microvascular flow. Microvascular blood flow resistance has a strong impact on cardiovascular function and tissue perfusion. The flow resistance in microcirculation is governed by flow behavior of blood through a complex network of vessels, where the distribution of red blood cells across vessel cross-sections may be significantly distorted at vessel bifurcations and junctions. We investigate the development of blood flow and its resistance starting from a dispersed configuration of red blood cells in simulations for different hematocrits, flow rates, vessel diameters, and aggregation interactions between red blood cells. Initially dispersed red blood cells migrate toward the vessel center leading to the formation of a cell-free layer near the wall and to a decrease of the flow resistance. The development of cell-free layer appears to be nearly universal when scaled with a characteristic shear rate of the flow, which allows an estimation of the length of a vessel required for full flow development, $l_c \approx 25D$, with vessel diameter $D$. Thus, the potential effect of red blood cell dispersion at vessel bifurcations and junctions on the flow resistance may be significant in vessels which are shorter or comparable to the length $l_c$. The presence of aggregation interactions between red blood cells lead in general to a reduction of blood flow resistance. The development of the cell-free layer thickness looks similar for both cases with and without aggregation interactions. Although, attractive interactions result in a larger cell-free layer plateau values. However, because the aggregation forces are short-ranged at high enough shear rates ($\bar{\dot{\gamma}} \gtrsim 50~\text{s}^{-1}$) aggregation of red blood cells does not bring a significant change to the blood flow properties. Also, we develop a simple theoretical model which is able to describe the converged cell-free-layer thickness with respect to flow rate assuming steady-state flow. The model is based on the balance between a lift force on red blood cells due to cell-wall hydrodynamic interactions and shear-induced effective pressure due to cell-cell interactions in flow. We expect that these results can also be used to better understand the flow behavior of other suspensions of deformable particles such as vesicles, capsules, and cells. Finally, we investigate segregation phenomena in blood as a two-component suspension under Poiseuille flow, consisting of red blood cells and target cells. The spatial distribution of particles in blood flow is very important. For example, in case of nanoparticle drug delivery, the particles need to come closer to microvessel walls, in order to adhere and bring the drug to a target position within the microvasculature. Here we consider that segregation can be described as a competition between shear-induced diffusion and the lift force that pushes every soft particle in a flow away from the wall. In order to investigate the segregation, on one hand, we have 2D DPD simulations of red blood cells and target cell of different sizes, on the other hand the Fokker-Planck equation for steady state. For the equation we measure force profile, particle distribution and diffusion constant across the channel. We compare simulation results with those from the Fokker-Planck equation and find a very good correspondence between the two approaches. Moreover, we investigate the diffusion behavior of target particles for different hematocrit values and shear rates. Our simulation results indicate that diffusion constant increases with increasing hematocrit and depends linearly on shear rate. The third part of the study describes development of a simulation model of complex vascular geometries. The development of the model is important to reproduce vascular systems of small pieces of tissues which might be gotten from MRI or microscope images. The simulation model of the complex vascular systems might be divided into three parts: modeling the geometry, developing in- and outflow boundary conditions, and simulation domain decomposition for an efficient computation. We have found that for the in- and outflow boundary conditions it is better to use the SDPD fluid than DPD one because of the density fluctuations along the channel of the latter. During the flow in a straight channel, it is difficult to control the density of the DPD fluid. However, the SDPD fluid has not that shortcoming even in more complex channels with many branches and in- and outflows because the force acting on particles is calculated also depending on the local density of the fluid.
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Background. Indirect revascularization is a therapeutic approach in case of severe angina not suitable for percutaneous or surgical revascularization. Transmyocardial revascularization (TMR) is one of the techniques used for indirect revascularization and it allows to create transmyocardial channels by a laser energy bundle delivered on left ventricular epicardial surface. Benefits of the procedure are related mainly to the angiogenesis caused by inflammation and secondly to the destruction of the nervous fibers of the heart. Patients and method. From September 1996 up to July 1997, 14 patients (9 males – 66.7%, mean age 64.8±7.9 years) underwent TMR. All patients referred angina at rest; Canadian Angina Class was IV in 7 patients (58.3%), III in 5 (41.7%). Before the enrollment, coronarography was routinely performed to find out the feasibility of Coronary Artery Bypass Graft (CABG): 13 patients (91,6%) had coronary arteries lesions not suitable for direct revascularization; this condition was limited only to postero-lateral area in one patient submitted to combined TMR + CABG procedures. Results. Mean discharge time was 3,2±1,3 days after surgery. All patients were discharged in good clinical conditions. Perfusion thallium scintigraphy was performed in 7 patients at a mean follow-up of 4±2 months, showing in all but one an improvement of perfusion defects. Moreover an exercise treadmill improvement was observed in the same patients and all of them are in good clinical conditions, with significantly reduced use of active drugs. Conclusion. Our experience confirms that TMR is a safe and feasible procedure and it offers a therapeutic solution in case of untreatable angina. Moreover, it could be a hybrid approach for patients undergoing CABGs in case of absence of vessels suitable for surgical approach in limited areas of the heart.
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Aim. We report a case of ulnar and palmar arch artery aneurysm in a 77 years old man without history of any occupational or recreational trauma, vasculitis, infections or congenital anatomic abnormalities. We also performed a computed search of literature in PUBMED using the keywords “ulnar artery aneurysm” and “palmar arch aneurysm”. Case report. A 77 years old male patient was admitted to hospital with a pulsing mass at distal right ulnar artery and deep palmar arch; at ultrasound and CT examination a saccular aneurysm of 35 millimeters at right ulnar artery and a 15 millimeters dilatation at deep palmar arch were detected. He was asymptomatic for distal embolization and pain. In local anesthesia ulnar artery and deep palmar arch dilatations were resected. Reconstruction of vessels was performed through an end-to-end microvascular repair. Histological examination confirmed the absence of vasculitis and collagenopaties. In postoperative period there were no clinical signs of peripheral ischemia, Allen’s test and ultrasound examination were normal. At follow-up of six months, the patient was still asymptomatic with a normal Allen test, no signs of distal digital ischemia and patency of treated vessel with normal flow at duplex ultrasound. Conclusion. True spontaneous aneurysms of ulnar artery and palmar arch are rare and can be successfully treated with resection and microvascular reconstruction.
Resumo:
Neuronal stretching during concussion alters glucose transport and reduces neuronal viability, also affecting other cells in the brain and the Blood Brain Barrier (BBB). Our hypothesis is that oxidative stress (OS) generated in neurons during concussions contributes to this outcome. To validate this, we investigated: (1) whether OS independently causes alterations in brain and BBB cells, namely human neuron-like, neuroblastoma cells (NCs), astrocyte cells (ACs) and brain microvascular endothelial cells (ECs), and (2) whether OS originated in NCs (as in concussion) is responsible for causing the subsequent alterations observed in ACs and ECs. We used H2O2 treatment to mimic OS, validated by examining the resulting reactive oxygen species, and evaluated alterations in cell morphology, expression and localization of the glucose transporter GLUT1, and the overall cell viability. Our results showed that OS, either directly affecting each cell type or originally affecting NCs, caused changes in several morphological parameters (surface area, Feret diameter, circularity, inter-cellular distance), slightly varied GLUT1 expression and lowered the overall cell viability of all NCs, ACs, and ECs. Therefore, we can conclude that oxidative stress, which is known to be generated during concussion, caused alterations in NCs, ACs, and ECs whether independently originated in each cell or when originated in the NCs and could further propagate the ACs and ECs.
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Nos últimos anos com a evolução dos sistemas de saúde tem-se verificado uma melhoria na qualidade dos serviços médicos prestados, conduzindo a uma esperança média de vida mais longa. Muitas patologias, apesar de patentes, são tratadas e/ou controladas de modo a permitir que a população possa adquirir um estilo de vida normal. As doenças cardiovasculares com o seu carácter multidimensional, têm consequências graves para o cidadão comum, para a sociedade e para o sistema de saúde, o que determina que sejam encaradas como um dos mais importantes problemas de saúde pública, problema este que urge minorar. Dentro das doenças cardiovasculares, a cardiopatia isquémica tem um significado relevante, uma vez que, engloba condições que necessitam de cuidados médicos especiais, em situações de emergência, como o enfarte agudo do miocárdio e a angina de peito (estável e instável). O médico dentista deve estar atento ao doente com cardiopatia isquémica, tendo em conta os cuidados especiais em consultório dentário que o mesmo necessita. A recolha de uma anamnese detalhada e história clínica atualizada, são fundamentais para o sucesso do tratamento dentário. O médico dentista deverá estar habilitado para atuar em situações de emergência e ter o consultório devidamente equipado, de forma a agir em conformidade com estes possíveis eventos.