RESUMEN
After the emergence of the SARS-CoV-2 virus in early 2020, it quickly became clear that symptomatic or asymptomatic infection had the potential to negatively impact on an individual's fitness to dive through effects on the respiratory, cardiovascular or neurological systems. The significance of these effects in the military diving environment was initially unclear due to an absence of data concerning incidence, chronology or severity. In order to safely return divers to the water and maintain operational capability, the UK Military developed a pathway for SARS-CoV-2 positive divers that stratified risk of sequelae and extent of required clinical investigation, while minimising reliance on viral testing and hospital-based investigations. We present this process, provide rationale and support for its design and detail the number of SARS-CoV-2 positive divers who have been returned to full diving fitness following infection of varying degrees of severity.
RESUMEN
Endosalpingiosis, traditionally regarded as an incidental pathological finding, was recently reported to have an association with gynecologic malignancies. To determine the prevalence of endosalpingiosis, we evaluated all benign appearing adnexal lesions using the Sectioning and Extensively Examining-Fimbria (SEE-Fim) protocol, and queried the pathology database for the presence of endosalpingiosis, gynecologic malignancy, endometriosis, Walthard nests, and paratubal cysts. Using the SEE-Fim protocol, the prevalence of endosalpingiosis, endometriosis, Walthard nests, and paratubal cysts were 22%, 45%, 33%, and 42% respectively, substantially higher than previously reported. All lesions were observed to increase with age except endometriosis which increased until menopause then decreased dramatically. Among specimens including ovarian tissue, the prevalence of implantation of at least one lesion type was ubiquitous in patients age 51 and older (93%). The clinical significance of endosalpingiosis should be a continued area of research with larger trials assessing prevalence, factors affecting incidence, and association with malignancy. Our findings contribute to elucidating the origin of ectopic lesions and gynecologic disease risk.
Asunto(s)
Enfermedades de las Trompas Uterinas/epidemiología , Enfermedades de los Genitales Femeninos/epidemiología , Enfermedades de los Anexos/epidemiología , Enfermedades de los Anexos/patología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Coristoma/epidemiología , Coristoma/patología , Endometriosis/epidemiología , Endometriosis/patología , Enfermedades de las Trompas Uterinas/patología , Trompas Uterinas/patología , Femenino , Enfermedades de los Genitales Femeninos/patología , Neoplasias de los Genitales Femeninos/epidemiología , Neoplasias de los Genitales Femeninos/patología , Humanos , Persona de Mediana Edad , Prevalencia , Estudios Retrospectivos , Adulto JovenRESUMEN
Accelerometry (ACC) shows promise as an easily implemented clinical measure of balance. The purpose of the study was to estimate test-retest reliability of ACC measures and determine the relationship between ACC measured at the pelvis and underfoot center of pressure (COP) measures during sensory organization test (SOT) conditions. Eighty-one subjects were recruited from the community with no known orthopedic or vestibular deficits (19-85 years). Subjects completed three consecutive, ninety second trials for each of the six SOT conditions, while wearing the accelerometer. ACC and COP time series were described by calculating the normalized path length, root mean square (RMS), and peak-to-peak values. The test-retest reliability of the three measures within each SOT condition was estimated over three trials using the intraclass correlation coefficient. ACC and COP test-retest reliability were similar, ranging from 0.63 to 0.80 using ACC and 0.42 to 0.81 using COP for the measure of normalized path length. Linear regression between ACC and COP measures showed significant correlation under almost every SOT condition using both single and average measures across trials. The degree of association between COP and ACC was equivalent when using the first trial or the 3-trial average, suggesting that one trial may be sufficient. The use of accelerometry may have value in estimating balance function and minimizing clinical evaluation time.
Asunto(s)
Equilibrio Postural/fisiología , Aceleración , Adulto , Anciano , Anciano de 80 o más Años , Fenómenos Biomecánicos , Femenino , Pie/fisiología , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Pelvis/fisiología , Presión , Reproducibilidad de los Resultados , Adulto JovenAsunto(s)
Analgésicos/administración & dosificación , Dolor/prevención & control , Sacarosa/administración & dosificación , Administración Oral , Sistema Nervioso Central/efectos de los fármacos , Humanos , Lactante , Periodo Intraoperatorio , Nociceptores/efectos de los fármacos , Dimensión del DolorRESUMEN
About 600,000 people in the United States are estimated to be affected by venous ulcers. The cornerstone of care of chronic venous ulcers involves the application of compression bandages. Other therapies include treatment of associated infection, treatment for edema and inflammation, and debridement when necessary. Repifermin, a recombinant human KGF-2 (fibroblast growth factor-10), exerts a proliferative effect on epithelial cells, in vitro and in vivo, and has been shown to accelerate wound healing in several experimental animal models. A randomized, double-blind, parallel-group, placebo-controlled, multicenter study was conducted to evaluate the safety and efficacy of topical repifermin treatment, for 12 weeks, in the healing of chronic venous ulcers in 94 patients. Repifermin was shown to accelerate wound healing, with significantly more patients achieving 75% wound closure with repifermin than with placebo. The treatment effect appeared more marked for a subgroup of patients with initial wound areas < or = 15 cm2 and wound ages of < or = 18 months. A longer duration of treatment (e.g., 26 weeks) may allow better differentiation of the benefit of repifermin compared with placebo, particularly with respect to complete wound closure. The safety assessment showed that repifermin was well tolerated.
Asunto(s)
Factores de Crecimiento de Fibroblastos/administración & dosificación , Úlcera Varicosa/tratamiento farmacológico , Cicatrización de Heridas/efectos de los fármacos , Administración Tópica , Adulto , Anciano , Anciano de 80 o más Años , Enfermedad Crónica , Método Doble Ciego , Femenino , Factor 10 de Crecimiento de Fibroblastos , Factores de Crecimiento de Fibroblastos/efectos adversos , Factores de Crecimiento de Fibroblastos/uso terapéutico , Humanos , Masculino , Persona de Mediana Edad , Factores de Tiempo , Úlcera Varicosa/patología , Úlcera Varicosa/fisiopatología , Cicatrización de Heridas/fisiologíaRESUMEN
INTRODUCTION: Postoperative care after infrarenal abdominal aortic aneurysm (AAA) repair has traditionally involved admission to the intensive care unit (ICU). With the advent of endovascular AAA repair, the management of open procedures has received increased scrutiny. We recently modified our AAA clinical pathway to include selective use of the ICU. METHODS: Consecutive elective infrarenal AAA repairs performed by members of the vascular surgery division at a university medical center from 1994 to 1999 were analyzed retrospectively with a computerized database, the Medical Archival Retrieval System. Group I consisted of 245 patients who were treated in the ICU for 1 or more days, and Group II included 69 patients admitted directly to the floor. Ruptured, symptomatic, suprarenal, endovascular, and reoperative repairs were excluded. Outcome variables were compared over the 6-year period. RESULTS: Floor admissions increased over the study period with 0%, 0%, 3.3%, 16.3%, 48.6%, and 43.6% of patients admitted directly to the surgery ward from 1994 to 1999. The average ICU length of stay declined from 4.6 to 1.2 days, whereas the hospital length of stay decreased from 12.5 to 6.8 days from 1994 to 1999. The change in ICU use had no effect on death (2.4% in Group I vs 0% in Group II). Major and minor morbidity was comparable. Hospital charges were significantly lower for patients in Group II. CONCLUSION: A policy of selective utilization of the ICU after elective infrarenal AAA repair is safe. It can reduce resource use without a negative impact on the quality of care.
Asunto(s)
Aneurisma de la Aorta Abdominal/cirugía , Vías Clínicas , Unidades de Cuidados Intensivos/estadística & datos numéricos , Anciano , Aneurisma de la Aorta Abdominal/economía , Aneurisma de la Aorta Abdominal/epidemiología , Implantación de Prótesis Vascular , Comorbilidad , Procedimientos Quirúrgicos Electivos , Femenino , Precios de Hospital , Humanos , Unidades de Cuidados Intensivos/economía , Tiempo de Internación , Masculino , Pennsylvania , Cuidados Posoperatorios/economíaRESUMEN
BACKGROUND: One goal of wound healing research is to discover agents to accelerate healing. Regulatory agencies have suggested stringent criteria to determine efficacy, that of 100% wound closure. Data analysis at a single point such as 100% closure does not provide detailed information about agent effectiveness over the entire span of healing. HYPOTHESIS: Wound healing trajectories can provide such information and can be used to demonstrate utility as alternative end points for wound healing trials. DESIGN: Data from 160 patients in 11 clinical trials of diabetic foot ulcers conducted at 2 centers were evaluated. Wound healing trajectories were constructed for patients whose wounds healed (100% closure) and those whose did not (<100% closure) over a 20-week period. The percentage of patients achieving total healing vs time of treatment was plotted and divided into patients receiving a test agent or placebo. RESULTS: The healing trajectories were almost identical for patients achieving complete healing at the 2 centers, as were the trajectories for patients with less than 100% closure. However, the trajectories of patients achieving total healing were significantly different from those not achieving 100% closure. Fifty-two percent of all patients achieved 100% healing by 20 weeks; 61% of patients receiving an experimental agent had total healing compared with 39% of placebo-treated patients. Linear regression suggested that all patients would achieve total healing by 37 weeks. CONCLUSIONS: Since wound healing trajectories for diabetic foot ulcers treated at 2 centers so closely mimic one another, trajectories might be useful efficacy end points, and used to compare significant points along a continuum rather than a single static end point. Shifting of the wound healing trajectory from an impaired to a more ideal course may be considered when determining efficacy of new wound treatments.
Asunto(s)
Cicatrización de Heridas/efectos de los fármacos , Desbridamiento , Pie Diabético/tratamiento farmacológico , Neuropatías Diabéticas/tratamiento farmacológico , Florida , Humanos , Pennsylvania , Pronóstico , Estudios Prospectivos , Estadísticas no Paramétricas , Análisis de Supervivencia , Factores de TiempoRESUMEN
OBJECTIVE: The compression of femoral artery pseudoaneurysms is a time consuming, painful, and sometimes unsuccessful procedure. Thrombin injection has been advocated as a superior alternative. In this study, we compare our experiences with both techniques. METHODS: All the records of femoral artery false aneurysms that were treated in the vascular laboratory from January 1996 to April 1999 were retrospectively reviewed. Treatment with ultrasound scan-guided compression was compared with treatment with dilute thrombin injection (100 U/mL). RESULTS: Both groups had similar demographics and aneurysm sizes (P >.2). Of the pseudoaneursyms, 88% were caused by cardiac catheterization and the others were the results of femoral artery access for cardiac surgery (6%), arteriography (5%), and renal dialysis (1%). Compression was successful in 25 of 40 patients (63%). Nine persistent aneurysms necessitated operation, and six were treated successfully with thrombin injection. Primary thrombin injection successfully obliterated 21 pseudoaneurysms in 23 patients. Overall, 27 of 29 pseudoaneurysms were treated successfully with thrombin injection (93%). Thrombosis occurred within seconds of the thrombin injection and required, on average, 300 units of thrombin (100 to 600 units). The patients who underwent successful compression required an average of 37 minutes of compression (range, 5 to 70 minutes) and required analgesia on several occasions. No patients in the thrombin group required analgesia or sedation. Neither group had complications. A cost analysis shows that thrombin treatment results in considerable savings in vascular laboratory resource use but not in overall hospital expenditures. CONCLUSION: Ultrasound scan-guided thrombin injection is a safe, fast, and painless procedure that completely obliterates femoral artery pseudoaneurysms. The shift from compressive therapy to thrombin injection reduces vascular laboratory use and is less expensive, although it does not significantly impact hospital costs.
Asunto(s)
Aneurisma Falso/terapia , Arteria Femoral , Técnicas Hemostáticas , Trombina/administración & dosificación , Adulto , Anciano , Anciano de 80 o más Años , Aneurisma Falso/diagnóstico por imagen , Femenino , Arteria Femoral/diagnóstico por imagen , Humanos , Inyecciones Intraarteriales , Masculino , Persona de Mediana Edad , Dimensión del Dolor , Presión , Estudios Retrospectivos , Resultado del Tratamiento , UltrasonografíaRESUMEN
The results of a combined analysis and separate analyses of four multicenter, randomized, parallel group studies that evaluated the effects of once-daily topical administration of becaplermin gel for the treatment of chronic, full thickness, lower extremity diabetic ulcers are presented. The four studies included a total of 922 patients with nonhealing lower extremity diabetic ulcers of at least 8 weeks' duration. Following initial complete sharp debridement of the ulcer, patients were randomized to receive a standardized regimen of good ulcer care alone, good ulcer care plus placebo gel, or good ulcer care plus becaplermin gel-30 microg/g, or good ulcer care plus becaplermin gel-100 microg/g, with various combinations of regimens used in the four studies. Safety was assessed by monitoring adverse events and by clinical laboratory evaluations. Meta-analytic statistical techniques were used in the combined analysis to establish homogeneity of treatment comparisons across studies. Based on an analysis of patients with baseline ulcer area common to all trials (= 10 cm2), representing 95% of all patients, becaplermin gel-100 microg/g significantly increased (p = 0.007) the probability of complete healing compared with placebo gel. It was determined that for the median ulcer area of these patients, which was 1.5 cm2, the becaplermin gel-100 microg/g treatment group showed a 39% increase in complete healing compared with that of the placebo gel treatment group (50% vs. 36%, respectively, p = 0.007). Becaplermin gel-100 microg/g significantly decreased (p = 0.01) the time to complete healing compared with placebo gel, with the 35th percentile of time to complete healing being reduced by 30% (14.1 weeks vs. 20. 1 weeks, respectively). In patients with ulcers = 5 cm2 at baseline (a more homogeneous group), becaplermin gel-100 microg/g also significantly increased the incidence of complete healing with a similar decrease in the time to healing. Adverse events reported during treatment or during a 3-month follow-up period were not unexpected for this patient population and were similar in nature and incidence across all treatment groups. We therefore conclude that treatment with becaplermin gel at a dose of 100 microg/g once daily, in conjunction with good ulcer care, is effective and well tolerated in patients with full thickness lower extremity diabetic ulcers.
Asunto(s)
Úlcera del Pie/tratamiento farmacológico , Factor de Crecimiento Derivado de Plaquetas/uso terapéutico , Proteínas Recombinantes/uso terapéutico , Administración Tópica , Adulto , Anciano , Anciano de 80 o más Años , Becaplermina , Femenino , Geles , Humanos , Masculino , Persona de Mediana Edad , Estudios Multicéntricos como Asunto , Factor de Crecimiento Derivado de Plaquetas/administración & dosificación , Proteínas Proto-Oncogénicas c-sis , Ensayos Clínicos Controlados Aleatorios como Asunto , Proteínas Recombinantes/administración & dosificación , Resultado del TratamientoRESUMEN
BACKGROUND: Severe oxygen-dependent chronic obstructive pulmonary disease (COPD) is considered by many to be a contraindication to open abdominal aortic aneurysm (AAA) repair. We reviewed our own experience with this patient population. METHODS: From July 1995 to March 1999, 14 consecutive patients limited by home oxygen-dependent COPD underwent elective open infrarenal AAA repair. Their medical records were reviewed. RESULTS: The mean aortic aneurysm size was 6.3 cm. The mean PaO2 = 70 mm Hg, PaCO2 = 45 mm Hg, forced expiratory volume in 1 second (FEV1) = 34% of predicted, and forced vital capacity (FVC) = 67% of predicted. All 14 patients were extubated within 24 hours, mean length of hospital stay was 5.9 days, and there were no perioperative deaths. CONCLUSIONS: Severe home oxygen-dependent COPD is not a contraindication to safe elective open AAA repair.
Asunto(s)
Aneurisma de la Aorta Abdominal/cirugía , Enfermedades Pulmonares Obstructivas/complicaciones , Terapia por Inhalación de Oxígeno , Anciano , Aneurisma de la Aorta Abdominal/patología , Dióxido de Carbono/sangre , Dióxido de Carbono/metabolismo , Cuidados Críticos , Procedimientos Quirúrgicos Electivos , Femenino , Volumen Espiratorio Forzado/fisiología , Servicios de Atención de Salud a Domicilio , Hospitalización , Humanos , Intubación Intratraqueal , Tiempo de Internación , Enfermedades Pulmonares Obstructivas/fisiopatología , Enfermedades Pulmonares Obstructivas/terapia , Masculino , Oxígeno/sangre , Estudios Retrospectivos , Seguridad , Tasa de Supervivencia , Factores de Tiempo , Capacidad Vital/fisiologíaRESUMEN
PURPOSE: The purpose of this study was to delineate the natural history of the progression of asymptomatic carotid stenosis. METHODS: In a 10-year period, 1701 carotid arteries in 1004 patients who were asymptomatic were studied with serial duplex scans (mean follow-up period, 28 months; mean number of scans, 2.9/patient). At each visit, stenoses of the internal carotid artery (ICA) and the external carotid artery (ECA) were categorized as none (0 to 14%), mild (15% to 49%), moderate (50% to 79%), severe (80% to 99%), preocclusive, or occluded. Progression was defined as an increase in ICA stenosis to >/=50% for carotid arteries with a baseline of <50% or as an increase to a higher category of stenosis if the baseline stenosis was >/=50%. The Cox proportional hazards model was used for data analysis. RESULTS: The risk of progression of ICA stenosis increased steadily with time (annualized risk of progression, 9.3%). With multivariate modeling, the four most important variables that affected the progression (P <.02) were baseline ipsilateral ICA stenosis >/=50% (relative risk [RR], 3.34), baseline ipsilateral ECA stenosis >/=50% (RR, 1.51), baseline contralateral ICA stenosis >/=50% (RR, 1.41), and systolic pressure more than 160 mm Hg (RR, 1. 37). Ipsilateral neurologic ischemic events (stroke/transient ischemic attack) occurred in association with 14.0% of the carotid arteries that were studied. The progression of ICA stenosis correlated with these events (P <.001), but baseline ICA stenosis was not a significant predictor. CONCLUSION: In contrast to recently published studies, we found that the risk of progression of carotid stenosis is substantial and increases steadily with time. Baseline ICA stenosis was the most important predictor of the progression, but baseline ECA stenosis also was identified as an important independent predictor. Contralateral ICA stenosis and systolic hypertension were additional significant predictors. We found further that the progression of ICA stenosis correlated with ischemic neurologic events but not baseline stenosis. The data provide justification for the use of serial duplex scans to follow carotid stenosis and suggest that different follow-up intervals may be appropriate for different patient subgroups.
Asunto(s)
Estenosis Carotídea/patología , Anciano , Presión Sanguínea , Arterias Carótidas/diagnóstico por imagen , Arterias Carótidas/patología , Estenosis Carotídea/complicaciones , Estenosis Carotídea/diagnóstico por imagen , Estenosis Carotídea/fisiopatología , Trastornos Cerebrovasculares/etiología , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Análisis Multivariante , Modelos de Riesgos Proporcionales , Factores de Riesgo , Sensibilidad y Especificidad , UltrasonografíaRESUMEN
Diabetic foot ulcers are a significant healthcare problem affecting more than 1 million patients at some point in their lifetime. Good ulcer care begins with thorough assessment of the ulcer, which includes determining whether the ulcer is infected and whether neuropathy or peripheral vascular disease is present. The principles of good wound care include use of proper footwear, non-weight-bearing limb support, use of appropriate antibiotics, debridement, aggressive revascularization, control of serum glucose levels, and careful monitoring of the ulcer. For refractory ulcers, new therapies, such as the use of exogenous recombinant growth factors, are being developed that may have a significant benefit in treating these ulcers and lowering the amputation rate.
Asunto(s)
Pie Diabético/prevención & control , Cicatrización de Heridas , Antibacterianos/uso terapéutico , Vendajes , Pie Diabético/terapia , Pie/irrigación sanguínea , Pie/cirugía , Sustancias de Crecimiento/uso terapéutico , Humanos , Guías de Práctica Clínica como Asunto , Factores de RiesgoRESUMEN
BACKGROUND: Endovascular repair of abdominal aortic aneurysms (AAA) is gaining momentum although it is not yet approved in the United States by regulatory agencies. The Endovascular Grafting System (EGS), the first device to enter clinical trials in 1993, is now in phase III testing. METHODS: We reviewed the first 50 patients to undergo an EGS repair of AAA over 24 months at our institution. Results were compared with 69 patients who underwent open repair during the same time period by the same surgeon. RESULTS: Devices were successfully implanted in 47 of 50 (94%) patients. Three were converted to standard repair. Although length of stay was shorter, costs were similar. Follow-up was 3 to 24 months. Perigraft flow was noted in 33% at discharge; 73% of those stopped either spontaneously or with coiling. Three graft limbs occluded, requiring thrombolytic therapy. CONCLUSIONS: The EGS repair of AAA is feasible and effective. Cooperation between surgery and radiology is important for the success of a new endovascular program.
Asunto(s)
Aneurisma de la Aorta Abdominal/cirugía , Implantación de Prótesis Vascular/métodos , Anciano , Anciano de 80 o más Años , Aneurisma de la Aorta Abdominal/diagnóstico por imagen , Aortografía , Implantación de Prótesis Vascular/efectos adversos , Estudios de Evaluación como Asunto , Femenino , Estudios de Seguimiento , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Factores de Tiempo , Tomografía Computarizada por Rayos XRESUMEN
Growth factors exert a powerful influence over wound healing. They control the growth, differentiation, and metabolism of cells. Although their influence on wound repair has been studied, there are only a few reports in which growth factors applied topically exerted a positive influence on wound repair. However, there is no doubt that they do control the wound environment. It is likely that their actions will be defined further, and the wound environment will be able to be controlled to achieve complete and durable wound healing in patients.
Asunto(s)
Sustancias de Crecimiento/farmacología , Cicatrización de Heridas/efectos de los fármacos , Factor de Crecimiento Epidérmico/farmacología , Humanos , Factor de Crecimiento Derivado de Plaquetas/farmacología , Proteínas Recombinantes/farmacología , Somatomedinas/farmacología , Factores de Crecimiento Transformadores/farmacología , Cicatrización de Heridas/fisiologíaRESUMEN
Most evidence indicates that nitric oxide plays a role in normal wound repair; however, involvement of inducible nitric oxide synthase (iNOS) has not been established. Experiments were carried out to determine the requirement for iNOS in closing excisional wounds. Wound closure was delayed by 31% in iNOS knockout mice compared with wild-type animals. An identical delay in wound closure was observed in wild-type mice given a continuous infusion of the partially selective iNOS inhibitor N6-(iminoethyl)-L-lysine. Delayed wound healing in iNOS-deficient mice was completely reversed by a single application of an adenoviral vector containing human iNOS cDNA (AdiNOS) at the time of wounding. Reverse transcription PCR identified iNOS mRNA expression in wild-type mice peaking 4-6 d after wounding, and confirmed expression of human iNOS in the adenoviral vector containing human iNOS cDNA-treated animals. These results establish the key role of iNOS in wound closure, and suggest a gene therapy strategy to improve wound healing in iNOS-deficient states such as diabetes, and during steroid treatment.
Asunto(s)
Técnicas de Transferencia de Gen , Óxido Nítrico Sintasa/genética , Cicatrización de Heridas , Células 3T3 , Actinas/genética , Actinas/metabolismo , Adenoviridae/genética , Animales , Células Cultivadas , ADN Complementario/genética , Inhibidores Enzimáticos/farmacología , Expresión Génica , Terapia Genética/métodos , Humanos , Lisina/análogos & derivados , Lisina/farmacología , Ratones , Ratones Noqueados , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa/antagonistas & inhibidores , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo II , Reacción en Cadena de la Polimerasa , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transcripción GenéticaRESUMEN
Growth factors applied topically to wounds can accelerate healing by stimulating granulation tissue formation and enhancing epithelialization. This has been suggested by several different studies of topically applied growth factors. It is clear, however, that topical growth factor therapy should not be considered as a substitute for good wound care, including surgical debridement or revascularization.
Asunto(s)
Sustancias de Crecimiento/fisiología , Cicatrización de Heridas/fisiología , Plaquetas/metabolismo , HumanosRESUMEN
PURPOSE: A pathologic feature commonly associated with abdominal aortic aneurysms is the presence of variably sized and shaped intraluminal thrombus, which may be fundamental to the disease process. However, the precise role of the intraluminal thrombus in the formation, enlargement, and rupture of abdominal aortic aneurysms is unknown. The hypothesis tested in this study was whether there were structural features of aortic thrombi to suggest that it may be involved in the pathogenesis of abdominal aortic aneurysms. We have investigated this hypothesis using a variety of structural and biochemical techniques. METHODS: Tests performed were light, transmission, and scanning electron microscopy; fluid permeability measurements; and Western blots. RESULTS: Intraluminal thrombus found in abdominal aortic aneurysms is structurally complex and is traversed from the luminal to abluminal surface by a continuous network of interconnected canaliculi. Quantitative microscopic analysis of the thrombus shows cellular penetration for at least 1 cm from the luminal surface of the thrombus. Macro-molecular penetration may be unrestricted throughout the entire thickness of the thrombus. Fibrin deposition occurred throughout the thrombus, whereas fibrin degradation occurred principally at the abluminal surface. CONCLUSIONS: These principally structural studies support the hypothesis that the thrombus is a self-sustaining entity that may have significance in the pathophysiologic mechanism of abdominal aortic aneurysms.