Vascular Function in Chronic Kidney Disease and in Renovascular Disease

Cardiovascular mortality is 15 to 30 times higher in patients with chronic kidney disease than in the age-adjusted general population. Even minor renal dysfunction predicts cardiovascular events and death in the general population. In patients with atherosclerotic renovascular disease the annual cardiovascular event and death rate is even higher. The abnormalities in coronary and peripheral artery function in the different stages of chronic kidney disease and in renovascular disease are still poorly understood, nor have the cardiac effects of renal artery revascularization been well characterized, although considered to be beneficial. This study was conducted to characterize myocardial perfusion and peripheral endothelial function in patients with chronic kidney disease and in patients with atherosclerotic renovascular disease. Myocardial perfusion was measured with positron emission tomography (PET) and peripheral endothelial function with brachial artery flow-mediated dilatation. It has been suggested that the poor renal outcomes after the renal artery revascularization could be due to damage in the stenotic kidney parenchyma; especially the reduction in the microvascular density, changes mainly evident at the cortical level which controls almost 80% of the total renal blood flow. This study was also performed to measure the effect of renal artery stenosis revascularization on renal perfusion in patients with renovascular disease. In order to do that a PET-based method for quantification of renal perfusion was developed. The coronary flow reserve of patients with chronic kidney disease was similar to the coronary flow reserve of healthy controls. In renovascular disease the coronary flow reserve was, however, markedly reduced. Flow-mediated dilatation of brachial artery was decreased in patients with chronic kidney disease compared to healthy controls, and even more so in patients with renovascular disease. After renal artery stenosis revascularization, coronary vascular function and renal perfusion did not improve in patients with atherosclerotic renovascular disease, but in patients with bilateral renal artery stenosis, flow-mediated dilatation improved. Chronic kidney disease does not significantly affect coronary vascular function. On the contrary, coronary vascular function was severely deteriorated in patients with atherosclerotic renovascular disease, possibly because of diffuse coronary artery disease and/or diffuse microvascular disease. The peripheral endothelial function was disturbed in patients with chronic kidney disease and even more so in patient with atherosclerotic renovascular disease. Renal artery stenosis dilatation does not seem to offer any benefits over medical treatment in patients with renovascular disease, since revascularization does not improve coronary vascular function or renal perfusion.

Morphometric Study of Cerebral Arterioles in CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy(CADASIL) is the most common hereditary small vessel disease (SVD) leading to vascular dementia. The cause of the disease is mutations in NOTCH3 gene located at chromosome 19p13.1. The gene defect results in accumulation of granular osmiophilic material and extracellular domain of NOTCH3 at vascular smooth muscle cells (VSMCs) with subsequent degeneration of VSMCs. This arteriopathy leads to white matter (WM) rarefaction and multiple lacunar infarctions in both WM and deep grey matter (GM) visible in magnetic resonance imaging. This thesis is focused on the quantitative morphometric analysis of the stenosis and fibrosis in arterioles of the frontal cerebral WM, cortical GM and deep GM (lenticular nucleus (LN), i.e. putamen and globus pallidus). It was performed by assessing four indicators of arteriolar stenosis and fibrosis: (1) diameter of arteriolar lumen, (2) thickness of arteriolar wall, (3) external diameter of arterioles and (4) sclerotic index. These parameters were assessed (a) in 5 elderly CADASIL patients with the mean age of onset 47 years and of death 63 years, (b) in a 32-year-old young CADASIL patient with the first ischemic episode at the age of 29 years and (c) a very old CADASIL patient aged 95 years, who suffered the first stroke at the age of 71 years. These measurements were compared with age-matched controls without stroke, dementia, hypertension, and cerebral amyloid angiopathy. Morphometric analyses disclosed that in all age groups of CADASIL patients compared to corresponding controls there was significant narrowing of arteriolar lumen (stenosis) and fibrotic thickening of the walls (fibrosis) in the WM arterioles, although the significance of stenosis in the very old patient was marginal. In the LN arterioles there was only significant fibrosis without stenosis. These results suggest that the ischemic lesions and lacunar infarcts in the cerebral WM are mainly attributable to the stenosis of arterioles, whereas those in the LN are probably mainly due to hemodynamic changes of the cerebral blood flow. In conclusion: The SVD of CADASIL is characterized by narrowing of lumina and fibrotic thickening of walls predominantly in the cerebral WM arterioles. On the other hand, in the LN the ischemic lesions and lacunar infarcts are most probably hemodynamic due to impaired autoregulation caused by the rigidity of fibrotic arterioles. The pathological cerebral arteriolar alterations begin to develop already at a relatively young age but the onset may be delayed to a remarkably old age. This underlines the well known great variability in the clinical picture of CADASIL. The very late onset of CADASIL may cause its underdiagnosis, because the strokes are common in the elderly and are attributed to common risk factors.

Application of Computational Fluid Dynamics in Modeling Blood Flow in Human Thoracic Aorta

The aim of this study was to simulate blood flow in thoracic human aorta and understand the role of flow dynamics in the initialization and localization of atherosclerotic plaque in human thoracic aorta. The blood flow dynamics in idealized and realistic models of human thoracic aorta were numerically simulated in three idealized and two realistic thoracic aorta models. The idealized models of thoracic aorta were reconstructed with measurements available from literature, and the realistic models of thoracic aorta were constructed by image processing Computed Tomographic (CT) images. The CT images were made available by South Karelia Central Hospital in Lappeenranta. The reconstruction of thoracic aorta consisted of operations, such as contrast adjustment, image segmentations, and 3D surface rendering. Additional design operations were performed to make the aorta model compatible for the numerical method based computer code. The image processing and design operations were performed with specialized medical image processing software. Pulsatile pressure and velocity boundary conditions were deployed as inlet boundary conditions. The blood flow was assumed homogeneous and incompressible. The blood was assumed to be a Newtonian fluid. The simulations with idealized models of thoracic aorta were carried out with Finite Element Method based computer code, while the simulations with realistic models of thoracic aorta were carried out with Finite Volume Method based computer code. Simulations were carried out for four cardiac cycles. The distribution of flow, pressure and Wall Shear Stress (WSS) observed during the fourth cardiac cycle were extensively analyzed. The aim of carrying out the simulations with idealized model was to get an estimate of flow dynamics in a realistic aorta model. The motive behind the choice of three aorta models with distinct features was to understand the dependence of flow dynamics on aorta anatomy. Highly disturbed and nonuniform distribution of velocity and WSS was observed in aortic arch, near brachiocephalic, left common artery, and left subclavian artery. On the other hand, the WSS profiles at the roots of branches show significant differences with geometry variation of aorta and branches. The comparison of instantaneous WSS profiles revealed that the model with straight branching arteries had relatively lower WSS compared to that in the aorta model with curved branches. In addition to this, significant differences were observed in the spatial and temporal profiles of WSS, flow, and pressure. The study with idealized model was extended to study blood flow in thoracic aorta under the effects of hypertension and hypotension. One of the idealized aorta models was modified along with the boundary conditions to mimic the thoracic aorta under the effects of hypertension and hypotension. The results of simulations with realistic models extracted from CT scans demonstrated more realistic flow dynamics than that in the idealized models. During systole, the velocity in ascending aorta was skewed towards the outer wall of aortic arch. The flow develops secondary flow patterns as it moves downstream towards aortic arch. Unlike idealized models, the distribution of flow was nonplanar and heavily guided by the artery anatomy. Flow cavitation was observed in the aorta model which was imaged giving longer branches. This could not be properly observed in the model with imaging containing a shorter length for aortic branches. The flow circulation was also observed in the inner wall of the aortic arch. However, during the diastole, the flow profiles were almost flat and regular due the acceleration of flow at the inlet. The flow profiles were weakly turbulent during the flow reversal. The complex flow patterns caused a non-uniform distribution of WSS. High WSS was distributed at the junction of branches and aortic arch. Low WSS was distributed at the proximal part of the junction, while intermedium WSS was distributed in the distal part of the junction. The pulsatile nature of the inflow caused oscillating WSS at the branch entry region and inner curvature of aortic arch. Based on the WSS distribution in the realistic model, one of the aorta models was altered to induce artificial atherosclerotic plaque at the branch entry region and inner curvature of aortic arch. Atherosclerotic plaque causing 50% blockage of lumen was introduced in brachiocephalic artery, common carotid artery, left subclavian artery, and aortic arch. The aim of this part of the study was first to study the effect of stenosis on flow and WSS distribution, understand the effect of shape of atherosclerotic plaque on flow and WSS distribution, and finally to investigate the effect of lumen blockage severity on flow and WSS distributions. The results revealed that the distribution of WSS is significantly affected by plaque with mere 50% stenosis. The asymmetric shape of stenosis causes higher WSS in branching arteries than in the cases with symmetric plaque. The flow dynamics within thoracic aorta models has been extensively studied and reported here. The effects of pressure and arterial anatomy on the flow dynamic were investigated. The distribution of complex flow and WSS is correlated with the localization of atherosclerosis. With the available results we can conclude that the thoracic aorta, with complex anatomy is the most vulnerable artery for the localization and development of atherosclerosis. The flow dynamics and arterial anatomy play a role in the localization of atherosclerosis. The patient specific image based models can be used to diagnose the locations in the aorta vulnerable to the development of arterial diseases such as atherosclerosis.

Conduta terapêutica atual no adenocarcinoma da cárdia e da junção esofagogástrica

Adenocarcinomas of the cardia and gastroesophageal junction are peculiar entities with three different origins, which differ somewhat from other adenocarcinomas of the stomach in their clinical presentation and pathogenesis, and have a poorer prognosis. In this article the authors reviewed definitions, incidence and epidemiology, etiologic factors, genetic implications, clinical presentation, diagnosis, staging and treatment, with emphasis on the surgical approach, discussing the current management of these cancers. The prognostic factors related specifically to the cardia cancers are: esophageal invasion greater than 3cm, microscopic residual tumor and wall penetration (>T2). Preoperative workup should include computed tomography, and endoscopic ultrasonography and laparoscopy when available. Preoperative recognition of T3/ T4/N2 lesions should indicate inclusion in neo-adjuvant protocols whenever possible. The authors present the results of 46 resected cases of adenocarcinomas of the cardia and GE junction of the Instituto Nacional do Câncer- Brazil (1981-1995). Cure was intended in 29 and palliation in 17 patients. The most common type of resection was total gastrectomy with abdominal esophagectomy (28 cases). Morbidity (major and minor) occurred in 50% of the patients. The main causes were of respiratory origin and fistulas (19.6% each). Death occurred in 44% of the patients with fistula. Postoperative death until the 30th day occurred in 17.24% of the curative cases and in 23.52% of the palliative ones. The median survival time was 68.5 months for stage I, 25 months for stage II, 31 months for stage III and 12.5 months for stage IV diseases. The median survival time was 8 months for palliation and 28.5 months for cure. No long-term survival was obtained with the palliative group, whereas 25% survived five years of more in the curative group. The authors conclude that the surgical approach should be the one the surgeon feels more comfortable with. Complete removal of the disease proved by frozen section, splenectomy and D2 lymphadenectomy should be the standard therapy with curative intent.

Estenose arterial pós-transplante hepático: tratamento com angioplastia transluminal percutânea

Vascular complications after liver transplantation include oclusion or stenosis at the sites of anastomosis in the hepatic artery, portal vein, and vena cava. Balloon angioplasty of these stenosis carries little risk and is a useful procedure for the treatment of these problems. The purpose of this paper was to assess whether percutaneous transluminal angioplasty can help to prolong allograft survival and impruve allograft function in patient with hepatic artery stenosis after liver transplantation. We report a 43-year-old mate with stenosis of hepatic artery anastomosis after liver transplantation. An abrupt elevation of liver enzymes and serum bilirrubin levels was noted on the fifth postoperative month. The patient underwent percutaneous liver biopsy, which revealed important ductal depletion due to hypoperfusion, even though Doppler ultrasound examination demonstrated arterial flow. An angiogram confirmed severe stenosis of the arterial anastomosis with poor intraparenchymal arterial perfusion pattern. In an attempt to preserve the graft, a percutaneous transluminal angioplasty was performed using microballoons mounted on a hydrophylic micro guidewire. Intervention proceeded without complications. Liver enzimes and bilirrubin levels decreased within twenty-four hours of angioplasty. Normal levels were achieved after one week. Seven month after angioplasty, the patient is in a optimal clinical condition with no signs of graft impairment. We conclude that percutaneous transluminal angioplasty of hepatic artery stenosis after liver transplantation is relatively safe and may help decrease allograft loss.

Leiomioma do esôfago removido por videolaparoscopia

This report describes a leiomyoma of the inferior third section of the esophagus removed during laparoscopic cholecystectomy. The patient is a woman 55-years-age, carrying esophageal myoma of 40 mm in diameter wide, situated in the posterior wall of the lower esophagus. Indications for surgery were based mainly on the growth of the mass (6 mm when discovered 7 years previously, increased to 40 mm). Recently the patient returned suffering from pain, which could be attributed to his litiasic cholecystopaty. A small degree of low disphagia could also be observed. Radiologic imaging, direct endoscopic examination and endoscopic ultrasound showed that the mioma protruded on to the oesophagic lumen, discreetly diminishing there. A laparoscopic esophageal myomectomy was indicated at the same session of the laparoscopic cholecystectomy. Once the pneunoperitoneum was installed, five ports were placed as if for a hiatus hernia surgery. The cholecystectomy was uneventful. Next, an esophagoscopy was performed so as to determine the precise area covering the base of the tumour; at the right-lateral site. Longitudinal and circular fibres of the esophagus was severed over the lesion and the enucleation of the tumour was performed alternating the monopolar dissection, bipolar and hidrodisection. Control-endoscopy was carried out to verify mucosa integrity. Four suture points with poliglactine 3-0 string so as to close the musculature followed this. One suture was placed in for diminution of the size of the esophagean hiatus. Total time of intervention: two hours (30m for the cholecystectomy and one hour and thirty minutes for the myomectomy). Postoperative period: uneventful. Disappearance of the disphagia was observed. Radiologic transit control with water-soluble contrast at 4th post-operative day: good passage. Diagnosis from laboratory of pathology: conjunctive tumour formed by muscle non-striated cells: leiomyoma. The patient was re-examined on the two-month postoperative follow-up. General conditions were good and there were no complain of dysphagia. Neither there were any symptoms of gastro-esophageal reflux.

Fistula gastrocólica

A case of gastrocolic fistula(GCF) in a patient with duodenal stenosis who had previously undergone gastroenteric anastomosis is reported. The patient went through hemigastrectomy, partial colectomy and segmental enterectomy with bloc resection. Reconstruction was carried out through Billroth II gastrojejunostomy, jejunojejunostomy and end-to-end anastomosis of the colon. The patient had good post-operative evolution and was discharged from hospital seven days after surgery. GCF should be suspected in patients presenting weight loss, diarrhea and fecal vomiting, mainly with history of peptic ulcer surgery, gastric or colonic malignancy and use of steroidal and nonsteroidal antiinflamatory drugs. Barium enema is the choice test for diagnosis, however, the benign or malignant nature of the lesion should always be evaluated through high digestive endoscopy. Clinical treatment with oral H2-antagonists and discontinuing ulcerogenic medications might be indicated in some cases; surgical treatment is indicated in cases of malignant disease and might be indicated in cases of peptic disease as it treats GCF and also the baseline disease. Some advise upwards colostomy at first. The most used technique is bloc resection, including the fistulous tract, hemigastrectomy and partial colectomy. Gastrectomy, fistulous tract excision and colon suturing may be performed in some cases. The mortality rate is related to metabolic disorders and the recurrence with the use of antiinflammatory drugs.

Diverticulo epifrênico do esôfago

Disphagia is a very common complaint among patients seeking a gastroenterologists. Esophageal motility disorder is a frequent finding, at times associated with pulsion diverticula. We present a case of a 68 year old female patient with thoracic pain and double epiphrenic diverticula. The upper gastrointestinal tract examination revealed two epiphrenic diverticula, one with 6-7 cm and the other measuring 2 cm, located 30 cm from the dental arcade. She underwent surgical treatment to remove the larger diverticula, a long esophageal myotomy and a Belsey-Mark IV antireflux technique. She presented an uneventful recovery and is doing well I8 months following surgery.

Acalasia do esôfago: miotomia com transiluminação

Laparoscopic techniques have provided a new dimension to correct functional disorders of the esophagus, which has stimulated some investigators to recently report the use of laparoscopic cardiomyotomy in the treatment of esophageal achalasia. Now, a new instrument has been added to the current laparoscopic technique to offer a safer and easier method to proceed complete myotomy. After the dissection of the esophagogastric junction, a special catheter is introduced reaching the stomach. lt has an illuminated 10 cm extremity connected to a light source. lts withdrawal allows to visualize every muscle circular fiber by transillumination withan improved view provide by the laparoscopic optic system lens. This condition modifies the operative surgeon s attitude offering a better controlled situation over the procedure. The use of transillumination o fthe esophagogastric junction provides a good identification of the mucosa e submucosa avoiding the risk of esophageal perforation. It also helps to perform a complete myotomy preventing the ocurrence of persistent disphagia in the postoperative period. Cardiomyotomy with parcial fundoplication is possible by videolaparoscopic approach, now made easier with transillumination. This technique is safe and the functional results are similar to those observed in the literature for conventional open procedures, with the obvious advantages of the minimally invasive approach.

Estenose esofagiana congênita por coristoma

Oesophageal choristomas are a very uncommon cause of congenital oesophageal stenosis. A high index of suspection is necessary for differential diagnosis with commoner causes of oesophageal suboclusion in childhood, mainly acquired oesophageal obstruction caused by gastroesophageal reflux. We present a case report and review the clinical, endoscopic and radiologic features of the disease and consider the need for padronization of surgical techniques to treat this condition, which is still controversial.

Leiomiomas do esôfago removidos por vídeo-toracoscopia

This report describes three cases of esophageal leiomyomas successfully resected by thoracoscopy. Surgical enucleation through minimally invasive surgery is the treatment of choice for esophageal leiomyoma. The conventional approach through a formal thoracotomy has the potential of causing excessive pain and patient discomfort. Moreover, the hospital stay and the recovery period are prolonged. Indications for surgery were based mainly on the size of the mass (<4 cm) and the presence of dysphagia. In one case there was a clear suspicion of malignancy. The tumour was located in the lower thoracic esophagus (case 1), in the middle thoracic esophagus (case 2) and in the upper esophagus (case 3). The CT was useful in identifying the relationship between the lesion and the organs of the mediastinum. The barium swallow study was able to locate the lesion along the esophagus. The endosonography determined the boundaries of the lesions. A right thoracoscopic approach was undertaken. Dissection of the esophagus around its entire perimeter was never necessary because all tumours were anterior or right sided. The tumours were better grasped with a traction suture than with forceps. The hidrodissection was very helpful. The water-soluble contrast swallow, performed on the fourth postoperative day, was normal. Clinical results were satisfactory in all patients. Biopsies should never be performed when the mucosa overlying is normal.

Migração de clipe metálico para úlcera duodenal após colecistectomia videolaparoscópica: Ligaclip migration into a duodenal ulcer following laparoscopic cholecystectomy

We report a rare cause of pyloric stenosis caused by migration of surgical clips into a duodenal ulcer following laparoscopic cholecystectomy. Even after endoscopic removal of the clips the inflammatory reaction during the healing process caused a stenosis of the pylorus that eventually required a truncal vagotomy and gastroenterostomy.

Necrose da mucosa esofágica como complicação da cardiomiotomia à heller para tratamento de megaesôfago chagásico

This article presents a complication of the laparoscopic technique for Heller cardiomyotomy and anterior fundoplication. This procedure is safe and provides excellent relief of disphagia in esophageal achalasia. Nevertheless, there are rare but dangerous complications, such as late active digestive bleeding, presented in this paper which was resistant to conservative treatment and led to hypovolemic shock. Urgent laparotomy performed to identify and control bleeding, revealed necrosis of esophageal mucosa with a bleeding gastric vessel. Inadequate exposure of the gastroesophageal junction and an incision very close to the lesser curvature might have damaged the esophageal branches of the left gastric artery, leading to ischemic necrosis of the mucosa and exposure of the gastric wall and its vessels.

Angioplastia com implante de "stent" na artéria mesentérica superior

Endovascular techniques have been used to treat arterial stenosis throughout the vascular system. The goal of this work is to report one case of percutaneous transluminal angioplasty with primary stenting of the ostial segment of the superior mesenteric artery for treatment of chronic mesenteric ischemia.