RESUMEN
PURPOSE: This study was undertaken to evaluate the effect of blood flow on the dimensions and cellular composition of normal arteries and freshly placed vein grafts (VG). METHODS: Bilateral jugular vein interposition grafts were placed in the common carotid arteries of 12 New Zealand white rabbits, and blood flow was reduced on one side by external carotid artery ligation. Shear stress, tangential stress, vessel dimensions, and smooth muscle cell (SMC) proliferation of reduced-flow arteries and VG were compared with these measures in contralateral controls (CON). RESULTS: A sustained reduction in blood flow was documented at 4 weeks (13 +/- 4 ml/min reduced-flow vs 21 +/- 4 ml/min CON; p < 0.05). Reduced-flow carotid arteries had a smaller lumen radius and greater medial thickness compared with normal-flow arteries, but there was no difference in medial cross-sectional area or medial SMC volume and no differences in any intimal measurements. These changes resulted in normalization of shear stress (15.2 +/- 4.6 dynes/cm2 reduced-flow vs 13.6 +/- 2.5 dynes/cm2 CON; p = NS). All VG underwent a marked postimplantation hyperplasia in intima and media, but the major effect of flow reduction on VG dimensions occurred in the intima. Intimal thickness in reduced-flow VG was 60% greater than that in control VG (57 +/- 12 microns vs 35 +/- 5 microns; p = 0.05), and intimal area was 70% greater than that in controls (0.83 +/- 0.24 microns 2 vs 0.48 +/- 0.08 microns 2; p > 0.05). Smaller differences were found in medial thickness (74 +/- 4 microns reduced-flow vs 63 +/- 4 microns CON; p = 0.02) and medial area (1.03 +/- 0.36 microns 2 reduced-flow vs 0.84 +/- 0.22 microns 2 CON; p = 0.05). Intimal SMC volume in reduced-flow VG was 37% greater than that in control VG (p = 0.07). Tangential stress in VG equaled that in ipsilateral arteries, whereas shear stress in VG remained much lower than that in arteries. CONCLUSIONS: In this model, arteries and VG responded to flow reduction by wall thickening, but the mechanism differed. Arteries underwent medial remodeling, lumen caliber reduction, and shear stress normalization, whereas VG responded by an upward modulation of the proliferative response that follows graft placement. These data support a primary role for tangential stress and a secondary role for shear stress in determination of VG dimensions.
Asunto(s)
Velocidad del Flujo Sanguíneo/fisiología , Arteria Carótida Común/patología , Venas Yugulares/patología , Venas Yugulares/trasplante , Animales , Arteria Carótida Común/fisiopatología , Arteria Carótida Común/cirugía , Arteria Carótida Externa/cirugía , División Celular , Venas Yugulares/fisiopatología , Ligadura , Músculo Liso Vascular/patología , Conejos , Túnica Íntima/patología , Túnica Media/patologíaRESUMEN
The antiproliferative effect of heparin on cultured smooth muscle cells in proliferating human smooth muscle cells derived from clinical lesions of intimal hyperplasia was tested. Smooth muscle cells were obtained from stenotic segments excised from failing in situ saphenous vein bypass grafts in three patients. The nonadventitial portion of the excised tissue was explanted into cell culture using standard techniques without the addition of exogenous growth factors. Under these conditions, rapid cell outgrowth was observed from these explants, in contrast to minimal growth of smooth muscle cells from normal veins from the same patients. Immunohistochemical staining with antiactin antibody confirmed that the cells cultured from the stenotic lesions were smooth muscle cells. Incubation of these cells with porcine mucosal heparin revealed a significant (p less than .01) dose-dependent inhibition of cell proliferation as measured by radioactive thymidine incorporation. Mean inhibition of six subcultures tested ranged from 3 to 46%, at heparin concentrations of 1 to 1,000 micrograms/ml. The magnitude of heparin's antiproliferative effect varied among the cell lines from different patients, but 10-30% inhibition was consistently observed at heparin concentrations usually attained in vivo. The maximal inhibition achieved was 65% in one cell line at the highest heparin dose. We conclude that heparin exerts a significant antiproliferative effect on human smooth muscle cells cultured from intimal hyperplastic lesions from in situ saphenous vein bypass grafts.
Asunto(s)
Heparina/farmacología , Músculo Liso Vascular/efectos de los fármacos , Anciano , Recuento de Células , Células Cultivadas , Humanos , Hiperplasia/patología , Masculino , Persona de Mediana Edad , Desarrollo de Músculos , Músculo Liso Vascular/crecimiento & desarrollo , Músculo Liso Vascular/patología , Vena Safena/trasplanteRESUMEN
Angiography, angioscopy, and duplex scanning have each been advocated for intraoperative assessment of in situ saphenous vein grafts. We compared these three modalities during operation in a prospective, blinded study during the construction of 20 femoral-infragenicular in situ saphenous vein grafts. Each modality was used and interpreted by a surgeon blinded to the results of the other studies. Abnormalities requiring intervention were defined as (1) patent vein side branches, (2) residual valve cusps, and (3) anastomotic stenoses greater than 30%. Criteria, specific to the modality, corresponding to each category were prospectively defined. Fourteen residual valve cusps, 49 patent vein branches, and 6 anastomotic stenoses were suggested by at least one modality. Nine residual valve cusps, 32 patent vein branches, and no anastomotic stenoses were actually found (and corrected) by direct inspection. Sensitivity of detecting patent side branches for angiography, duplex scanning, and angioscopy was 44%, 12%, and 66%, respectively. Both angiography and angioscopy were significantly more sensitive than duplex scanning for detection of unligated side branches (p less than 0.01). Sensitivity of detecting residual valve cusps was 22% (angiography), 11% (duplex scanning), and 100% (angioscopy). Angioscopy was significantly more sensitive than either duplex scanning or angiography in detection of residual valve cusps (p less than 0.01). Since no anastomotic stenoses were confirmed, the false-positive rates for stenosis detection were 20% for angiography, 10% for duplex scanning, and 0% for angioscopy. Time requirement was 17 to 20 minutes and did not differ among the three modalities. No stenosis or arteriovenous fistula has been detected in any graft by postoperative duplex surveillance (mean, 10-month follow-up).(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Arteria Femoral/cirugía , Oclusión de Injerto Vascular/diagnóstico , Vena Safena/trasplante , Anastomosis Quirúrgica , Endoscopía , Oclusión de Injerto Vascular/diagnóstico por imagen , Humanos , Monitoreo Intraoperatorio , Valor Predictivo de las Pruebas , Estudios Prospectivos , Radiografía , Vena Safena/diagnóstico por imagen , Vena Safena/patología , Sensibilidad y Especificidad , Método Simple Ciego , UltrasonografíaRESUMEN
Since the natural history of specific superficial femoral artery stenoses is not known, we examined progression rates of superficial femoral artery stenoses in 45 lower extremities found when arteriograms were obtained of 38 patients for symptomatic atherosclerotic disease in the opposite leg or abdomen. These initial superficial femoral artery arteriograms were compared with later arteriograms in 25 limbs, duplex scans in 27 limbs, and both modalities in 7 limbs. After a mean interval of 37 months, most superficial femoral artery stenoses (72%) did not progress. However, 12 superficial femoral artery stenoses progressed (28%; mean follow-up, 37 months, including 7 that occluded (17%). Superficial femoral artery stenoses progressed among patients who complained of symptom progression at a rate faster than that among asymptomatic patients (15.6%/year vs 3%/year; p = 0.006). Superficial femoral artery lesions also progressed more rapidly among patients whose contralateral superficial femoral artery was occluded (10%/year vs 1.6%/year; p = 0.04). By multivariate regression analysis, symptom progression and smoking history were predictive of superficial femoral artery stenosis progression. In the seven patients whose superficial femoral artery stenoses progressed to occlusion, the average rate of stenosis progression was 12%/year (maximum predicted rate, 30% per year by 95% confidence limit). These results indicate that superficial femoral artery stenoses usually progress with synchronous symptomatic deterioration. Other than symptom progression, only cumulative smoking history and contralateral superficial femoral artery occlusion could be associated with superficial femoral artery stenosis progression in this small series.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Arteriopatías Oclusivas/fisiopatología , Arteria Femoral/fisiopatología , Anciano , Anciano de 80 o más Años , Aneurisma de la Aorta/diagnóstico por imagen , Aneurisma de la Aorta/fisiopatología , Arteriopatías Oclusivas/diagnóstico por imagen , Arteriosclerosis/diagnóstico por imagen , Arteriosclerosis/fisiopatología , Constricción Patológica/diagnóstico por imagen , Constricción Patológica/fisiopatología , Diabetes Mellitus Tipo 1/complicaciones , Femenino , Arteria Femoral/diagnóstico por imagen , Estudios de Seguimiento , Humanos , Hipertensión/complicaciones , Claudicación Intermitente/diagnóstico por imagen , Claudicación Intermitente/fisiopatología , Isquemia/diagnóstico por imagen , Isquemia/fisiopatología , Pierna/irrigación sanguínea , Masculino , Métodos , Persona de Mediana Edad , Pronóstico , Radiografía , Fumar/efectos adversos , Factores de Tiempo , UltrasonografíaRESUMEN
Pyogenic splenic abscess is a rare condition that tends to occur in patients with predisposing factors. The use of splenectomy or computed tomography-guided percutaneous drainage in 10 patients with splenic abscess is presented. In 8 of 10 cases, the diagnosis was based on abdominal computed tomography scan. Seven of 10 patients were treated with splenectomy, and 3 were managed with computed tomography-guided drainage. Abscess cultures included Escherichia coli, Enterobacter, Streptococcus viridans, Staphylococcus aureus, and Bacteroides fragilis. There were two morbidities and one death in the splenectomy group and no complications in those treated with percutaneous drainage. This review suggests a flexible approach in the management of splenic abscess. Although splenectomy remains the traditional treatment for bacterial splenic abscess, CT-guided drainage may be appropriate in carefully selected patients.
Asunto(s)
Absceso , Enfermedades del Bazo , Absceso/diagnóstico , Absceso/diagnóstico por imagen , Absceso/terapia , Adulto , Anciano , Anciano de 80 o más Años , Infecciones Bacterianas/diagnóstico , Infecciones Bacterianas/diagnóstico por imagen , Infecciones Bacterianas/terapia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Enfermedades del Bazo/diagnóstico , Enfermedades del Bazo/diagnóstico por imagen , Enfermedades del Bazo/terapia , Tomografía Computarizada por Rayos XRESUMEN
Biliary hemorrhage may occur in a variety of clinical settings, but spontaneous hemobilia has not been reported from a cirrhotic liver. We describe a case of major hepatic hemobilia in a patient with cirrhosis and no history of trauma. A 50-year-old woman had abdominal pain, melena, and profound anemia. An extensive workup did not show the site of bleeding but did show a mass in the gallbladder. Cholecystectomy was performed, and at operation the patient was found to have cirrhosis and portal hypertension. The gallbladder "mass" was simply an organized clot, and hemorrhage recurred postoperatively. On reoperation, bleeding from the ampulla of Vater was observed, confirming the diagnosis of hemobilia. She was treated with angiographic interruption of hepatic arterial flow, at which time bleeding ceased. Her total transfusion requirements included 46 units of blood. Through 16 months of follow-up the patient has had no recurrent bleeding and no evidence of encephalopathy. This case demonstrates that spontaneous hemobilia may indeed arise from a cirrhotic liver. Proximal interruption of arterial flow is usually not recommended for hemobilia, especially in the presence of portal hypertension and cirrhosis, but may be life-saving in selected patients.
Asunto(s)
Enfermedades de la Vesícula Biliar/cirugía , Hemorragia/cirugía , Cirrosis Hepática/complicaciones , Colecistectomía , Femenino , Enfermedades de la Vesícula Biliar/diagnóstico , Enfermedades de la Vesícula Biliar/etiología , Hemorragia/diagnóstico , Hemorragia/etiología , Humanos , Persona de Mediana Edad , UltrasonografíaRESUMEN
Vascular malformations of the tongue (hemangiomas, lymphangiomas, AV fistulae, etc.) compromise a significant portion of head and neck angiodysplastic lesions. Complications requiring treatment include bleeding, pain, and difficulties related to increased tongue volume. Treatment modalities have included embolization, excision, cryotherapy, sclerosis, radiation, and chemotherapy. The more aggressive therapies often result in major functional disability to loss of lingual tissue. A series of nine patients has been treated for one or more of the complications of lingual vascular malformations with either argon of Nd:YAG laser photocoagulation. The therapeutic objective was provision of symptomatic relief with conservation of functioning lingual tissue. Results have varied from good to excellent with markedly decreased bleeding frequency as well as reduction in lesion size. No serious complications, such as bleeding or invasive infection, have been noted. Laser phototherapy is beneficial in the palliation of selected benign lingual vascular malformations.
Asunto(s)
Hemangioma Cavernoso/cirugía , Hemangioma/cirugía , Terapia por Láser , Linfangioma/cirugía , Neoplasias de la Lengua/cirugía , Adolescente , Adulto , Argón , Niño , Preescolar , Estudios de Evaluación como Asunto , Femenino , Estudios de Seguimiento , Hemangioma/patología , Humanos , Lactante , Rayos Láser/efectos adversos , Linfangioma/patología , Masculino , Persona de Mediana Edad , Neoplasias de la Lengua/patologíaRESUMEN
Thirty-seven patients of mean age 52 with large dark nodular port wine stains were treated with argon and neodymium YAG lasers. The level of patient satisfaction was high (mean 7.1 on scale of 10) despite residual color in 36 of 37 patients. It was possible to accomplish flattening of the lesion and removal of nodules in all patients. In four patients, it was necessary to use neodymium YAG laser for removal of residual large vascular nodules following previous argon therapy. Twenty-nine patients required a mean number of 1.6 retreatments for residual tufts of vessels. An unusual finding was that of recurrent color deepening of lesion in three patients after initial improvement. This recurrence responded to treatment. Spontaneous bleeding or bleeding initiated by trauma such as shaving was a problem noted in 13 out of 37 patients.
Asunto(s)
Hemangioma/cirugía , Terapia por Láser , Neoplasias Cutáneas/cirugía , Adulto , Anciano , Comportamiento del Consumidor , Femenino , Estudios de Seguimiento , Hemangioma/patología , Humanos , Masculino , Persona de Mediana Edad , Neoplasias Cutáneas/patologíaRESUMEN
The carbon dioxide laser is useful for vaporizing lesions and applying incisions, the argon laser coagulates superficial vascular lesions and the neodymium-YAG laser is used for large vascular and more deeply situated lesions. Many patients with port-wine stains have been treated with excellent to poor results, major problems consisting of incomplete color removal and hypertrophic scarring (occurring in 4% to 23% of cases). While results are imperfect, patients are satisfied with the improvement in 86% of cases. Lasers have been used with good results for treating patients with strawberry angioma of infancy, pyogenic granuloma, telangiectasia of the face, decorative tattoos, genital condylomata and warts. The results of laser treatment of essential telangiectasia of the lower extremities have generally been poor. The CO(2) laser has been effective in excising small lesions and elevating skin flaps.