Biomedical subjects

Thomas S Riles

Publications and source records attributed to Thomas S Riles.

23 records · Page 2Linked to original sources

PubMed2003

A model for predicting occult carotid artery stenosis: screening is justified in a selected population.

OBJECTIVES: The diagnosis and treatment of carotid artery disease is an integral part of stroke prevention. However, a population of patients who would benefit from screening for carotid artery stenosis has not been well defined. As part of an institutional stroke-screening program, a modified, rapid duplex scan was developed to evaluate patients for occult carotid stenosis. The goal of this study was to evaluate risk factors predictive of carotid stenosis in a selected population, and to identify patients who would benefit from carotid screening. METHODS: Patients were eligible for the study if they were >60 years of age and had a history of hypertension, heart disease, current smoking, or family history of stroke. A modified carotid duplex scan that had been previously validated against formal duplex scanning was utilized; this involved visualization of the carotid bulb and proximal internal carotid artery where Doppler flow velocities were obtained and recorded. RESULTS: Screening was performed on 394 patients. Thirty-eight patients (9.6%) had either unilateral or bilateral carotid stenosis of > or =50%. Risk factors evaluated included smoking, hypertension, cardiac disease, or hypercholesterolemia. If none of these risk factors was present, the incidence of carotid stenosis was 1.8%. This increased to 5.8% with one risk factor, 13.5% with two risk factors, and 16.7% with three risk factors. Two of three patients with all four risk factors had carotid stenosis (66.7%). Logistic regression and prespecified contrast statements for multiple comparisons were used to assess the relationship between the presence of risk factors and occult carotid artery stenosis. The presence of any one of these risk factors was associated with a statistically significant increase in the presence of occult carotid stenosis (P <.01). This was also statistically significant for the presence of any two risk factors (P <.01) or three risk factors (P <.05). CONCLUSION: The prevalence of carotid stenosis significantly increases with the presence of one or more identifiable demographic risk factors in a selected population. Assuming the diagnosis and treatment of carotid stenosis are fundamental to stroke prevention, screening for carotid artery disease is justified in this group of patients.

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PubMed2002

Aneurysm morphology as a predictor of endoleak following endovascular aortic aneurysm repair: do smaller aneurysm have better outcomes?

Since the Food and Drug Administrations' approval of endovascular devices for abdominal aortic aneurysm (AAA) repair, clinicians have been relaxing the strict inclusion criteria present during the clinical trials. Although the long-term natural history of endoleaks remains unclear, attachment site leaks (type I) are believed to represent an ongoing risk for future rupture. We reviewed our experience with endovascular AAA repair to elucidate factors that predispose toward the development of endoleaks and found that larger AAAs are significantly more likely to have a short proximal neck and severe proximal angulation. These factors likely contribute to the significantly increased rate of type I endoleaks that occurred after endovascular repair of large AAAs. Small AAAs (<5) had the lowest rate of endoleaks overall (8.3%) and of type I endoleaks in particular (0%). We conclude that AAA size and morphology can be used to predict which aneurysms will experience attachment site endoleaks in their course; AAAs from 4.5 to 5 cm in diameter may be particularly well suited for endovascular repair in this regard.

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PubMed2002

Are type II (branch vessel) endoleaks really benign?

The natural history and clinical significance of type II or branch vessel endoleaks following endovascular aortic aneurysm (AAA) repair remain unclear. Some investigators have suggested that these endoleaks have a benign course and outcome and that they can be safely observed. The purpose of this study was to document the natural history and outcome of all type II endoleaks that have occurred following endovascular AAA repair at our institution. A review of a prospectively compiled database of all endovascular AAA repairs performed at our institution was performed. From this review, we determined that type II endoleaks appear to have a relatively benign course, with a reasonable chance of spontaneously sealing within a 2-year period. No cases of rupture or aneurysm enlargement were documented in patients with open type II leaks. However, almost one-third of the patients did not manifest a type II leak until after their initial CT scan. The implications of such a "delayed" leak are unclear. Careful follow-up remains mandatory in patients with type II endoleaks to better define outcome.

Angioplasty↗

PubMed2002

A reassessment of carotid endarterectomy in the face of contralateral carotid occlusion: surgical results in symptomatic and asymptomatic patients.

OBJECTIVE: Total occlusion of the contralateral internal carotid artery has often been considered to be a predictor of poor outcome after carotid endarterectomy (CEA) of ipsilateral carotid stenosis. Data from both the North American Symptomatic Carotid Endarterectomy Trial and the Asymptomatic Carotid Atherosclerosis Study have suggested this to be true. However, each of these trials had relatively few patients with contralateral occlusion in the surgical arms of the studies. Recently, advocates of carotid angioplasty and stenting have suggested that this technique may be preferable in patients with a contralateral occlusion because of the perceived poor outcome with surgery. The purpose of this study was to review a large series of CEAs performed in patients with contralateral occlusion to see whether results differed from patients with patent contralateral arteries and to determine whether the presence of preoperative symptoms was an important factor in outcome in these cases. PATIENTS AND METHODS: A review was conducted of a prospectively compiled database of all primary CEAs performed at our institution from 1985 to 1999. Surgery was performed on 2420 patients, of whom 338 (14.0%) had contralateral total occlusion. RESULTS: Patients with contralateral total occlusion were more likely to be symptomatic (65.7% versus 60.1%; P =.1), male (70.9% versus 58%; P <.001), and hypertensive (63.9% versus 58.4%; P =.07) with a positive smoking history (42.6% versus 31.4%; P <.001) than patients with patent contralateral carotid artery. No significant difference was seen in the rates of perioperative neurologic events between patients with contralateral occlusion (3.0%) and those without (2.1%; P =.34). Among the total of 913 asymptomatic patients, of whom 115 had contralateral occlusion, no difference was seen in the rate of perioperative neurologic events (1.8% for contralateral occlusion cases; 1.9% for cases without contralateral occlusion). Among the total of 1507 symptomatic patients, of whom 223 had contralateral occlusion, no significant difference was seen in the rate of perioperative neurologic events (3.7% for contralateral occlusion cases; 2.2% for cases without contralateral occlusion; P =.2). CONCLUSION: The presence of contralateral occlusion does not appear to increase the perioperative risk of CEA. Although the risk of CEA in symptomatic patients with contralateral occlusion may be slightly increased, this must be weighed against the risk with medical treatment alone. CEA can be performed safely in patients with contralateral occlusion, which should not necessarily be considered a high-risk condition for surgery in favor of angioplasty and stenting.

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PubMedDate not supplied

Successful management of carotid stenosis in a high-risk population at an inner-city hospital.

This is a retrospective review of all carotid endarterectomies (CEA) (n=91) done from 1993 to 2002 at an inner-city hospital (Group I). This group was compared to a randomly selected group of patients (n=445) treated at a private hospital (Group II). The same high-volume surgeons performed CEAs at both hospitals. The majority of Group I patients (71.4%) were members of racial minority groups. They were also more likely to be younger (p<0.001), hypertensive (p<0.03), diabetic (p<0.001), and current smokers (p<0.001); have contralateral carotid artery occlusion (p=0.04); and present with stroke (p<0.001) than Group II patients. Despite this, the incidence of postoperative myocardial infarction (2.2% vs 0.2%, p=0.08), stroke (1.1% vs 1.6%, NS), and death (1.1% vs 0%, NS) was comparable between the 2 groups. Aggressive preoperative workup for occult cardiac disease in Group I revealed an incidence of 25.9% (n=15). Of these, 5 (33.3%) were found to have coronary artery disease severe enough to warrant intervention before CEA. In an inner-city population with increased medical comorbidities, more severe cerebrovascular disease, and relatively low volume of carotid surgery, the results of CEA were comparable to those in patients treated at a high-volume private hospital. The presence of high-volume surgeons, operating at the low-volume municipal hospital, may contribute to the low complication rate. Finally, aggressive preoperative cardiac workup in this underserved population revealed a meaningful incidence of occult coronary artery disease requiring intervention before CEA.

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