Faculty Bibliography

Carotid artery stenosis can be evaluated noninvasively by ocular pneumoplethysmography (OPG-Gee). This simultaneously measures both ophthalmic artery pressures and is therefore capable of detecting pressure-reducing or hemodynamically significant carotid lesions. An OPG-angiography correlation was made for 200 carotid arteries in 110 patients. Sensitivity, specificity and overall accuracy were 91%, 89%, and 90% respectively, if calculated per artery. On a per patient basis these figures were 94%, 88%, and 91%. Applications of this rapid and simple technique in clinical practice include selection of patients for angiography and carotid endarterectomy, as well as early and late control of the operative results

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

Percutaneous phenol sympathectomy has been performed under fluoroscopic or CT guidance in 37 patients with extremely advanced vascular disease of the lower extremities. The technique is simple and well tolerated by the patient with a remarkably low incidence of complications. Of the 37 patients, 14 (38%) showed objective improvement and none of the patients experienced worsening of their ischemia. Results to date suggest that this procedure provides a sympathetic blockade as effectively as surgical sympathectomy in these patients with advanced disease

Intravenous digital subtraction angiography (DSA) was used to evaluate 22 patients with Leriche syndrome. The technique successfully demonstrated both the level of obstruction and the reconstitution of arterial flow to the lower extremities. In view of the relative safety of DSA, compared with the axillary approach in standard angiography, the authors believe that it should be the initial procedure for presurgical evaluation of Leriche syndrome

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

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

It is generally stated that ulceration of the carotid bifurcation plaque may give rise to embolization and symptoms of cerebral ischemia. It has been suggested that prophylactic carotid endarterectomy is indicated in asymptomatic patients if the angiogram is interpreted as showing ulceration. We therefore determined the accuracy of the radiologic diagnosis of ulceration by comparing the radiologic and morphologic findings in 155 carotid endarterectomies. Ulceration was diagnosed in 54% of the angiograms and 47% of the surgical specimens and was not related to the degree of stenosis. Angiography had a sensitivity of 73%, a specificity of 62% and an overall accuracy of 67%. For the non-flow-restrictive lesions these figures were 65%, 66%, and 66%. If surgery were based on the angiographic diagnosis of ulceration in plaques with less than 50% stenosis, 16 out of 42 operations (38%) would have been done unnecessarily. Variability of the angiographic diagnosis of ulceration is also shown by a high interobserver variability; two sets of two authors read the angiograms independently and disagreed in 24% of the cases. The decision to operate should not depend entirely upon the angiographic diagnosis of ulceration

Cerebral angiography often cannot distinguish between complete thrombosis or fibrosis of the internal carotid artery (ICA) and nonvisualization due to a total occlusion of the common carotid or origin of the ICA. Whereas surgery may be beneficial if the distal carotid is patent (type 1), thromboendarterectomy may be contraindicated if thrombus or fibrosis extend to the intracranial branches (type 2). Rapid sequential computerized tomography (RSCT) was used to examine 15 patients whose ICAs appeared occluded by angiography. Of four ICAs classed as type 1 by RSCT, three were found to be patent during surgical exploration, and carotid reconstruction was successfully performed. Three other ICAs classed as type 2 by RSCT were also surgically explored, and complete thrombosis was confirmed. The RSCT technique provides an effective and nonoperative means of determining whether a nonvisualized ICA is reconstructible