Role of conventional angiography in evaluation of patients with carotid artery stenosis demonstrated by Doppler ultrasound in general practice.

BACKGROUND AND PURPOSE: Previous studies have suggested that patients with carotid stenosis who are candidates for endarterectomy can be effectively identified on the basis of carotid Doppler ultrasound alone. Before widespread acceptance of this policy, the accuracy of carotid Doppler ultrasound outside selected centers and clinical trials needs to be evaluated. We performed a 12-month prospective study to evaluate the accuracy of Doppler ultrasound in identifying patients for carotid intervention in general practice settings. METHODS: Each patient referred to our endovascular service for diagnostic angiography to evaluate for carotid stenosis was interviewed and examined by a neurologist. Subjects consisted of symptomatic patients with >/=50% stenosis and asymptomatic patients with >/=60% stenosis by Doppler ultrasound. Information pertaining to demographic and cerebrovascular risk factors and the results of the carotid Doppler ultrasound were recorded. The severity of stenosis on angiograms was measured with North American Symptomatic Carotid Endarterectomy Trial criteria by a blinded observer. The results of both studies were compared to determine the relative accuracy of ultrasound results. RESULTS: Of 130 patients (mean age, 69+/-8.8 years) who met Doppler ultrasound criteria, 22 (17%) and 8 patients (6%) were found to have 30% to 49% or <30% stenosis by angiography, respectively. The positive predictive value of carotid Doppler ultrasound for identifying appropriate symptomatic candidates for carotid intervention (angiographic stenosis >/=50%) was 80%, with a false-positive value of 20%. The positive predictive value of carotid Doppler ultrasound for identifying appropriate asymptomatic candidates for carotid intervention (angiographic stenosis >/=60%) was 59%, with a false-positive value of 41%. Carotid endarterectomy or angioplasty and stent placement were undertaken subsequently in 60 (46%) of the patients. In 94 patients who underwent cerebral angiography alone, no complications were observed. CONCLUSIONS: The present accuracy of carotid Doppler ultrasound in general practice does not justify its use as the sole basis of selecting appropriate patients for carotid intervention. Given the relatively low rate of associated morbidity with present day techniques, additional confirmatory studies such as angiography should be performed in every patient before a decision regarding intervention is made.

Microvascular surgical anatomy of the vertebrobasilar junction.

OBJECTIVE: We examined the pertinent microvascular anatomy of 28 formalin-fixed brains to develop anatomic guidelines for aneurysm surgery in the region of the vertebrobasilar junction. METHODS: Using a surgical microscope, the outer diameters were observed for the following main arteries: vertebral, basilar, posteroinferior cerebellar, and anteroinferior cerebellar. The number of lower brain stem perforating arteries was examined in relation to their course. The distance between the arteries and their perforators was measured with respect to anatomic landmarks. RESULTS: The anatomy of the main arteries was characteristically variable, whereas the anatomy of the perforators was constant, particularly in terms of their numbers and points of penetration into the brain substance. The four major points of entry were the lateral medullary area just caudal to the posterior olivary sulcus, the posterior olivary sulcus, the small lateral fossa at the superior olivary groove, and the foramen cecum. Each of these areas coincides with the origin of common vertebrobasilar aneurysms. CONCLUSION: The anatomy of the main arteries was variable. In contrast, the perforators penetrated the adjoining brain stem at specific locations, regardless of the caliber of the main artery. Despite a small vertebral artery or its major branches, perforators penetrating the brain are significant and may effect the outcome of aneurysm surgery or endovascular procedures.

Thrombolysis of the cervical internal carotid artery before balloon angioplasty and stent placement: report of two cases.

The application of endovascular techniques to the treatment of cervical carotid artery bifurcation atherosclerosis has been delayed because of the fear of causing embolic events while traversing the diseased portion of the artery with an angioplasty balloon catheter. Symptomatic carotid arteries often contain fresh or partially digested intraluminal thrombus. Before we cross certain carotid bifurcation lesions with angioplasty catheters, we deliver 100,000 to 200,000 units of urokinase in an attempt to digest loose thrombus. We have witnessed changes in the angiographic appearance of the diseased portion of the vessel after urokinase treatment, such as widening of the lumen, that suggest clot lysis. We present two patients who had symptomatic internal carotid artery stenosis. Angiography showed irregular narrowing of the internal carotid artery origin. One patient was selected for angioplasty instead of carotid endarterectomy because of severe cardiac risk factors. The other patient had major angiographic risk factors manifested by poor collateral circulation. The angiographic findings and history of transient ischemic attacks led us to suspect the presence of soft, loose plaque debris or thrombus in both cases. Therefore, we performed thrombolysis with urokinase before angioplasty. Repeat angiography showed widening of the arterial lumen and smoothing of the plaque profile. Subsequent angioplasty and stent placement were uneventful. Intraarterial thrombolysis can produce a change in the angiographic appearance of symptomatic atherosclerotic lesions of the cervical carotid artery bifurcation. Digestion of intralesional thrombus may provide a safer environment for deployment of endovascular remodeling devices by decreasing the likelihood of embolic phenomena. We believe thrombolysis should be done before angioplasty in select patients.

Lumbar discectomy: use of an epidural morphine sponge for postoperative pain control.

A technique for extended ambulatory epidural pain control after lumbar discectomy is described; preliminary results with 45 patients are reported; and alternative methods of narcotic analgesia are reviewed. In this technique, an absorbable gelatin sponge (Gelfoam, Upjohn Co., Kalamazoo, MI) is contoured to the laminotomy defect, placed in methylprednisolone acetate (40-80 mg), and then injected with 2 to 4 mg of preservative-free morphine (a small needle was used to fill the sponge). The sponge is placed over the defect before closure. A review of office and hospital records was conducted. The series consisted of 33 men and 12 women (mean age, 39 yr; range, 24-57 yr); records showed narcotic use in 34 patients (parenteral in 3) and work-related injuries in 14 patients. Thirty-three patients were ambulatory postoperatively on the day of surgery; all were ambulatory by postoperative day (POD) 1. On the day of surgery, 18 patients did not require any postoperative analgesics; on POD 1, 22 patients did not require analgesics. Six patients received parenteral narcotics; four received one dose only, and two had two or more doses. Thirty-one patients were discharged from the hospital on POD 1, and 10 were discharged POD 2. The other patients were discharged from the hospital on POD 3 (three patients) or POD 4 (one patient). When they were discharged, all patients received a limited supply of acetaminophen with codeine for pain control at home. After discharge, phone follow-up (at 1 week) and office follow-ups (at 3-5 weeks) revealed only one patient with more than mild discomfort. Three patients required one-time bladder catheterization, and one patient had presumed discitis 1 month postoperatively. In a control group who had undergone surgery 3 months previously, the average day of discharge had been POD 3.07; no control patient had been discharged on POD 1, and only 20% had been discharged on POD 2. This method provides effective, safe, and extended analgesia after lumbar discectomy.

Cerebrospinal fluid penetration of cefpirome in patients with non-inflamed meninges.

Twenty patients (mean age 52 +/- 12 years, mean weight 75 +/- 15 kg) scheduled for elective myelogram or spinal anaesthesia were enrolled to determine the cerebrospinal fluid (CSF) penetration of a new expanded spectrum cephalosporin antibiotic, cefpirome (HR-810). A single 2 g intravenous dose of cefpirome was administered as a bolus between 1 and 8 h before lumbar puncture. Blood samples were collected at 15 pre-determined times and a single CSF sample was obtained at the time of lumbar puncture. Serum and CSF cefpirome concentrations were determined by high performance liquid chromatography. The mean maximal serum concentration of cefpirome was 264 +/- 76 mg/L. A mean steady-state volume of distribution of 20 +/- 4 L, clearance of 7.4 +/- 1.3 L/h, and half-life of 2.5 +/- 0.5 h were determined. Mean CSF concentrations were 0.50 +/- 0.11 mg/L at 1-2 h post dose (n = 4), 0.57 +/- 0.13 mg/L at 2-4 h post dose (n = 4), 0.76 +/- 0.34 mg/L at 4-6 h post dose (n = 7), and 0.83 +/- 0.29 mg/L at 6-8.3 h post dose (n = 5). Blood:brain barrier permeability to cefpirome may not be a limiting factor as CSF concentrations were rapidly attained. Further studies are required to determine the mechanism of cefpirome transport between plasma and CSF.

Complications of intracranial bypass for vertebrobasilar insufficiency.

The authors' initial experience with intracranial revascularization of vertebrobasilar insufficiency, reported previously, fortunately yielded reasonably good results with high patency rates but in some cases there were significant, albeit temporary, complications. Since that time, major brain-stem strokes have occurred in two patients following superficial temporal to superior cerebellar artery bypass procedures. This occurrence has caused the authors to reassess their experience with this procedure and review the published literature with regard to complications. This review and the results of the international bypass study on anterior circulation ischemia suggest that a very cautious and conservative approach should be taken prior to considering intracranial bypass to the superior cerebellar or posterior cerebral artery.

Ventriculitis after metrizamide lumbar myelography.

A 62-year-old man underwent lumbar metrizamide myelography complicated initially by a bout of aseptic chemical meningitis. Afterward, he suffered persistent headache, nausea, and blurred vision and, 12 weeks after his myelography, computed tomographic scans showed abnormalities consistent with a chronic ventriculitis. The case is presented; its pathological substrate and clinical implications are discussed.

Extracranial-intracranial arterial bypass and basilar artery ligation in the treatment of giant basilar artery aneurysms.

Two patients with giant aneurysms of the basilar artery treated with prophylactic extracranial-intracranial arterial bypass (EIAB) to the rostral brain stem before basilar artery ligation are presented. In both cases, the bypass provided considerable collateral flow to the upper basilar, posterior cerebral, and superior cerebellar arteries. Basilar artery ligation has been shown to be an effective, albeit dangerous, means of treating giant aneurysms of the basilar artery. The risk of significant brain stem ischemia after ligation is at least 30%. EIAB to the rostral brain stem should be considered whenever basilar artery ligation is performed, especially in cases where angiography demonstrates poor collateral circulation to the distal basilar artery.

Revascularization of the rostral brain stem.

The clinical and angiographic diagnosis of rostral brain stem vascular insufficiency is reviewed. The various possibilities for surgical revascularization of this area include anastomosis of the superficial temporal or occipital artery to the main stem of the posterior cerebral or superior cerebellar artery of their branches. A new technique for anastomosing the superficial temporal artery to the posterior cerebral artery in the tentorial incisura is presented, and other methods of rostral brain stem revascularization are considered. Indications for revascularization of the rostral brain stem are not clearly defined, but should include clinical and angiographic evidence of upper brain stem ischemia.