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Biomedical subjects

T S Riles

Publications and source records attributed to T S Riles.

At least 73 records · Page 4Linked to original sources
PubMed1988

Revascularization of the external carotid artery.

Numerous reports describe the relative effectiveness of external carotid artery (ECA) revascularization in patients with ipsilateral internal carotid artery occlusion. Most, however, suffer from small numbers of patients or lack of detailed follow-up data. In addition, controversy persists regarding the safety with which this procedure can be performed. Twenty-two patients underwent a total of 27 ECA revascularizations. There were no perioperative strokes or deaths. During a mean follow-up period of 46 months, no strokes occurred and only two patients suffered transient ischemic attacks. Revascularization of the ECA is an effective means of treating the patient with ipsilateral internal carotid artery occlusion and may be performed with minimal morbidity and mortality.

Adult↗
PubMed1988

Suggested standards for reports dealing with cerebrovascular disease. Subcommittee on Reporting Standards for Cerebrovascular Disease, Ad Hoc Committee on Reporting Standards, Society for Vascular Surgery/North American Chapter, International Society for Cardiovascular Surgery.

The evaluation of clinical reports on vascular disease is often made difficult by variations in descriptive terms, clinical classification, and outcome criteria. In 1983 the Joint Council of the Society for Vascular Surgery and the North American Chapter of the International Society for Cardiovascular Surgery created the Ad Hoc Committee on Reporting Standards to address these problems and recommend solutions. Some general problems were addressed in the initial report dealing with lower extremity ischemia. This article concerns clinical standards for reports dealing with cerebrovascular disease, suggests a scheme for clinical classification, and recommends standardized reporting practices for grading risk factors, angiographic and other diagnostic findings, and the results and complications of therapeutic intervention.

Cerebrovascular Disorders↗
PubMed1988

Intracranial hemorrhage after carotid endarterectomy.

Among 1500 carotid endarterectomies performed between 1975 and 1984, 11 ipsilateral intracranial hemorrhages (IH) occurred between the first and tenth postoperative days for an incidence of 0.7%. The mortality rate among these patients was 36%. The only recognizable predisposing factor was relief of high-grade carotid stenosis (greater than 90%) whereas other factors such as age (58 to 81 years), preoperative hypertension (systolic blood pressure 120 to 160 mm Hg), preoperative head CT scans showing recent infarction (only one in five positive), and preoperative cerebral infarction (only 1 of 11 patients) did not play a role. All patients had normal coagulation studies. No patient required a shunt because all tolerated cross-clamping of the carotid artery. Postoperative systolic blood pressures were 200 to 240 mm Hg in 6 of 11 patients. The time of occurrence of IH extended from the immediate postoperative period to the tenth postoperative day (mean interval 3.3 days). Treatment consisted of craniotomy in five patients; four survived and one recovered completely. Of the six patients treated nonoperatively, three survived and two completely recovered. IH shares equal incidence with recurrent thrombosis, cross-clamping ischemia, and embolization as a cause of perioperative stroke. Although all except IH can be prevented by current practice, the means of preventing IH are not apparent; however, careful monitoring of blood pressure to prevent uncontrolled hypertension deserves consideration.

Aged↗
PubMed1987

Surgical management of the patient with bilateral internal carotid artery occlusion.

The patient with bilateral internal carotid artery occlusion is at high risk for development of stroke. Medical management and extracranial-intracranial bypass do not appear to offer these patients any protection from symptoms of cerebrovascular insufficiency. Our initial treatment in 11 of 12 patients who had this pattern of extracranial arterial occlusion has been external carotid artery revascularization. Nineteen procedures were performed for symptomatic lesions in all cases except one. There were no perioperative strokes or deaths. During a mean follow-up of 44.7 months, no new strokes occurred. Among 10 patients undergoing external carotid artery revascularization alone, only one transient ischemic attack occurred in follow-up. Seven of the eight surviving patients are presently asymptomatic. External carotid artery revascularization may be an effective and durable treatment for the patient with bilateral internal carotid artery occlusion.

Adult↗
PubMed1987

Surgical therapy for the patient with internal carotid artery occlusion and contralateral stenosis.

With demonstration of the failure of extracranial-intracranial (EC-IC) bypass to reduce the incidence of stroke in patients with internal carotid artery (ICA) occlusion, controversy continues regarding the best method of stroke prevention in these high-risk persons. One approach, endarterectomy of stenotic lesions of the contralateral carotid bifurcation, has been used for 145 patients with ICA occlusion during the past 25 years. Presenting symptoms included focal transient ischemic attacks (TIAs) in 62 patients, stroke (CVA) in 57, and nonfocal TIAs in 16. Ten patients were asymptomatic. Nine patients (6.2%) sustained perioperative strokes, only three of which were ipsilateral to the endarterectomy. There were three perioperative deaths (2.1%). During the follow-up period (mean 4 years) there were 13 new strokes (9.2%), four of which were fatal. These late results compare favorably with patients from the cooperative study of EC-IC bypass with occlusion of one ICA, whether they received surgical treatment or were managed nonoperatively. With the exception of select situations where an occluded ICA may be reopened, we conclude that the best current therapy for these patients is close observation of the nonoccluded ICA and endarterectomy once a stenotic lesion is encountered.

Adult↗
PubMed1987

Glossopharyngeal nerve injury complicating carotid endarterectomy.

Injury can occur to several of the cranial nerves during carotid endarterectomy. Among these, glossopharyngeal nerve injury is an uncommon complication because it is remote from the field of dissection in most carotid procedures. From more than 2000 carotid operations four cases of symptomatic ninth cranial nerve injury were identified. Analysis revealed that dissection cephalad to the level of the hypoglossal nerve was a common feature of each and severe functional disability can result from glossopharyngeal nerve paresis. When mobilization of this nerve and division of the posterior belly of the digastric muscle and styloid process become necessary for additional exposure, the risk of glossopharyngeal nerve injury increases. Specific recommendations are made regarding management and maneuvers to help reduce the incidence of this uncommon, yet potentially serious, complication.

Aged↗
PubMed1987

The hemodynamics of beta-blockade in patients undergoing abdominal aortic aneurysm repair.

To assess the intraoperative and postoperative hemodynamic effects of beta-blockade and its benefits in limiting myocardial ischemia and infarction, a group of 32 patients scheduled for abdominal aortic aneurysm (AAA) surgery (group 1) was treated with oral metoprolol immediately before surgery and with intravenous metoprolol during the postoperative period. Mean age was 71 years, and mean ejection fraction was 56% (range 36% to 83%). Eight patients had a preoperative history of angina, 13 had a history of myocardial infarction, and five had electrocardiographic evidence of prior myocardial infarction. A group of 51 closely matched patients with AAA who did not receive metoprolol served as controls (group 2). In group 1, overall hemodynamic tolerance of metoprolol intraoperatively and postoperatively was good, and there was no incidence of congestive heart failure, hypotension, or asthma. Furthermore, in group 1 significant reduction of systolic blood pressure and heart rate was consistently noted at frequent intraoperative intervals and for 48 hr after surgery, with only a transient reduction of cardiac index. In group 1, only one patient (3%) suffered an acute myocardial infarction. In contrast, nine group 2 patients (18%; p less than .05) suffered perioperative myocardial infarction. Furthermore, only four (12.5%) group 1 patients developed significant cardiac arrhythmias as opposed to 29 group 2 patients (56.9%; p less than .001). These data demonstrate that beta-blockade with metoprolol is effective in controlling systolic blood pressure and heart rate both intraoperatively and postoperatively in patients undergoing repair of AAA and can significantly reduce the incidence of perioperative myocardial infarction and arrhythmias.

Aged↗
PubMed1986

Contralateral neurologic symptoms after carotid surgery: a nine-year follow-up.

A study was undertaken to observe the long-term clinical behavior of the contralateral, asymptomatic carotid artery of patients after unilateral carotid endarterectomy (UCE). A consecutive series of 182 patients undergoing UCE were followed up for 1 to 9 years (mean 4.2 years). The operated artery was symptomatic in 169 cases (92.8%) whereas in 13 (7.2%) it was asymptomatic but stenotic. Follow-up included an accounting of all hemispheric or focal neurologic events in the territory of the nonoperated artery, as well as associated cardiovascular risk factors. A total of 11 patients (6%) suffered stroke (CVA) and six (3.3%) had transient ischemic attacks (TIAs) in the distribution of the nonoperated carotid artery. By life-table analysis, major neurologic symptoms developed in 11.6% of patients within 5 years. Hypertension was an important prognostic factor: significantly more hypertensive patients had late contralateral neurologic symptoms (p less than 0.05, chi square). The cumulative incidence of CVA and TIA in these patients was 17.3% by life-table analysis at 5 years vs. 9.1% for normotensive patients. Since only a small proportion of the patients studied had a high-grade stenosis of the nonoperated artery, no conclusions could be made regarding its prognostic importance. The relevant published studies are discussed and compared with this report. Guidelines for the management and follow-up of the patient after UCE are discussed.

Adult↗
PubMed1985

Late axillary artery thrombosis in patients with occluded axillary-femoral bypass grafts.

The axillary-femoral bypass graft is an alternative to direct anatomic procedures for patients with aortoiliac occlusive disease. Touted for its low morbidity and mortality rates, with corresponding improved patency rates, this extra-anatomic procedure has been considered safe and effective. Noncompromising upper extremity ischemia and one case of upper extremity loss, associated with early graft thrombosis, have been reported previously. This article describes two cases of late axillary artery thrombosis, occurring 4 and 6 months after graft thrombosis, which severely jeopardized the viability of the ipsilateral upper extremity. Experience with these patients has shown that a thrombosed axillary-femoral bypass graft may jeopardize the viability of the ipsilateral upper extremity many months after its failure. The absence of information in the literature regarding this complication suggests this is a rare complication of thrombosed axillary-femoral grafts.

Aged↗
PubMed1985

The use of digitized intravenous angiography in a clinical setting. A retrospective review of 58 patients.

Digitized intravenous angiography (DIVA) is a frequently used alternative to conventional intra-arterial angiography for the evaluation of cerebrovascular disease. In an attempt to identify factors that may increase the diagnostic capacity of DIVA, a retrospective study of 58 patients evaluated by DIVA for cerebrovascular disease was performed. The reason for the DIVA study was the presence of focal symptoms in 25 patients and nonfocal or vertebrobasilar symptoms in nine. Twenty-four patients were asymptomatic. DIVA was found to be adequately diagnostic in 37 patients (64%), and further evaluation was required in 21 (36%). When the 42 patients who had ocular pneumoplethysmography (OPG-Gee) results available were classified according to their presenting symptoms, 85% of those with focal symptoms and positive OPG-Gee had a diagnostically successful DIVA study. A high DIVA accuracy rate was also obtained in the asymptomatic patients, whether the OPG-Gee results were positive (60%) or negative (78%). The category of patients for whom the DIVA was the least successful was the group with nonfocal or vertebrobasilar symptoms. As many as 56% of these patients required additional testing. Thus it appears that the yield of diagnostic DIVA is increased when the clinical presentation and noninvasive testing are considered. A prospective study is underway to further verify this hypothesis.

Aged↗
PubMed1985

The value of the radionuclide angiogram in the prediction of perioperative myocardial infarction in patients undergoing lower extremity revascularization procedures.

To better define the group of patients at high risk of myocardial infarction (MI) and death associated with lower extremity revascularization procedures, resting gated blood pool studies were obtained in 100 such patients before surgery and results were correlated with the prevalence of perioperative MI. The results indicated that three patient groups could be distinguished on the basis of cardiac ejection fraction. Group I (n = 50) had preoperative ejection fractions ranging from 56% to 83%. None of the patients in group I suffered an acute perioperative MI. Group II (n = 42) comprised patients with ejection fractions ranging from 36% to 55%. There was a 19.0% prevalence of MI in group II, with one cardiac death. Group III included eight patients with ejection fractions ranging from 26% to 35%. There was a 75% prevalence of perioperative MI in these patients, with one cardiac death. All perioperative MIs occurred within the first 48 hr after surgery. Statistical analysis demonstrated a significantly higher prevalence of perioperative MI in patients with gated pool ejection fractions of 35% or less compared with the prevalence in patients with one or more of the other widely used clinical signs of increased cardiac operative risk (p less than .02).

Aged↗
PubMed1984

The value of radionuclide angiography as a predictor of perioperative myocardial infarction in patients undergoing abdominal aortic aneurysm resection.

To define the group of patients at high risk for myocardial infarction (MI) and death associated with abdominal aortic aneurysm repair, resting gated blood pool studies were obtained on 50 such aneurysm patients preoperatively. The results indicated that three groups could be distinguished among these patients by cardiac ejection fraction. Group I (n = 25) had preoperative ejection fractions ranging from 56% to 85%. None of the patients in group I suffered an acute perioperative MI. Group II (n = 20) comprised patients with ejection fractions ranging from 36% to 55%. There was a 20% incidence of MI in group II but no cardiac deaths. Group III included five patients with ejection fractions ranging from 27% to 35%. There was an 80% incidence of perioperative MI in these patients, with one cardiac death and one cardiac arrest. All perioperative MIs occurred within the first 48 hours after surgery. In addition there was a 50% incidence of perioperative MI among all those patients who were 80 years of age or older. These results indicate guidelines for the management of patients undergoing abdominal aortic aneurysm repair based on their preoperative ejection fraction. The data further suggest that the noninvasive gated blood pool method of determining ejection fraction may serve a more broadly useful function in helping to determine which of those patients about to undergo major surgical procedures are at high risk for perioperative MI.

Aged↗
PubMed1984

Common carotid occlusion. Assessment of the distal vessels.

In patients with common carotid artery (CCA) occlusion, successful vascular reconstruction can be performed if there is a patent internal or external carotid distal to the occlusion. Preoperative selection of suitable candidates is often difficult because of the inability to visualize patent distal vessels with conventional angiography. In reviewing 24 patients operated upon for CCA occlusion since 1962, the distal internal or external carotid arteries were visualized in only four (17%) of the preoperative angiograms. When these 24 patients were explored, the internal carotid was found to be patent in 11 (46%) patients and the external patent in 15 (62%) cases. Of the 15 patients reconstructed, thromboendarterectomy was performed in six and saphenous vein bypass in nine. In the remaining nine patients, exploration revealed both the internal and external carotids to be thrombosed and unsuitable for CCA reconstruction. Recently we have used rapid sequential computerized tomography (RSCT) scanning to aid in the evaluation of the nonvisualized internal carotid artery (ICA). In two patients with CCA occlusion, RSCT correctly diagnosed patency of the ICA although it appeared to be occluded on angiography. Preliminary data suggest that RSCT will permit accurate preoperative selection of those CCA occlusion patients who are suitable surgical candidates and eliminate the need for surgical exploration.

Adult↗
PubMed1984

Asymptomatic vena caval fistulization complicating abdominal aortic aneurysm.

Aortocaval fistulization is usually manifested by signs of rupture of an aneurysm or of the large fistula. Absence of symptoms is unusual with this rare complication. Two cases of asymptomatic aortocaval fistula are presented. An awareness of this possibility should facilitate management when unexpected venous bleeding is encountered.

Aged↗
PubMed1983

Criteria for interpretation of ocular pneumoplethysmography (Gee).

Ocular pneumoplethysmography (OPG) (Gee) is one of the most widely used tests for evaluation of carotid artery disease. Its usefulness depends on its diagnostic accuracy, which depends on the criteria used for interpretation of OPG tracings. Application of different criteria as suggested in the literature by Gee et al, McDonald et al, Baker et al, Eikelboom, and O'Hara et al on 200 OPG tests compared with angiography resulted in variations of sensitivity from 70% to 95%, specificity from 70% to 94%, and overall accuracy from 75% to 90%. In validating OPG, one has to be aware of these substantial differences. We found the criteria of McDonald et al the most suitable for clinical use.

Carotid Artery Diseases↗
PubMed1983

Axilloaxillary bypass for symptomatic stenosis of the subclavian artery.

Since the association has been made between stenosis of the subclavian artery and neurologic symptoms, controversy has existed over the preferred surgical procedure for bypass. In addition, concern has been raised regarding the long-term patency and effectiveness of this extraanatomic procedure in relieving neurologic symptoms. Twenty-seven patients underwent this operation for posterior cerebral symptoms between 1973 and 1982; 25 were followed for up to 77 months (mean 26 months). Twenty-two patients had complete relief of symptoms, although 3 of them required a subsequent carotid endarterectomy. Two other patients had partial relief, and one patient's symptoms remained unchanged. Upper extremity symptoms, present in nine patients, were relieved by the operation. All grafts remained patent during follow-up. Axilloaxillary bypass is a durable procedure for symptomatic stenosis of the subclavian artery. It is a low-risk procedure and is therefore particularly suited for older patients with associated carotid artery disease.

Aged↗
PubMed1983

The importance of hemorrhage in the relationship between gross morphologic characteristics and cerebral symptoms in 376 carotid artery plaques.

In a prospective study 376 carotid artery plaques (275 symptomatic, 101 asymptomatic) were obtained from endarterectomies (184 unilateral and 96 bilateral) in 280 patients. The gross morphologic features of each plaque were noted at surgery and, together with the patient's clinical history, stored in computer memory. These data were analyzed in order to investigate the relationship of gross morphologic plaque characteristics with both the presence of cerebral symptoms and the degree of stenosis associated with the plaque. Ulceration was the most frequently observed of the five major gross plaque morphologic characteristics (46.0% of all plaques), but only intramural hemorrhage (30.6% of all plaques) was significantly more common in all symptomatic compared with all asymptomatic plaques (p less than 0.02). Hemorrhage was also the only gross characteristic significantly more common in focal symptomatic plaques when compared with either asymptomatic plaques (p less than 0.05) or nonfocal symptomatic plaques (p less than 0.01). When all the plaques were divided into three broad degrees of stenosis groups (0-39%, 40-69%, 70-99%) on the basis of angiographic data, only hemorrhage showed a significant correlation in incidence with increased degree of plaque stenosis, both when all plaques were considered (p less than 0.001) and when only symptomatic plaques were examined (p less than 0.001). The results indicate that intramural hemorrhage is the only carotid plaque gross morphologic characteristic significantly more frequent in symptomatic compared with asymptomatic plaques and the only characteristic significantly correlated with increased plaque size. These findings indicate that factors other than plaque ulceration and intraluminal thrombus play an important role in carotid plaque related cerebral symptoms. The data also raise questions concerning the unequivocal value of anticoagulant therapy in carotid artery disease, especially in highly stenotic lesions.

Adult↗