J. Max Findlay

Role of transcranial Doppler monitoring in the diagnosis of cerebral vasospasm after subarachnoid hemorrhage

OBJECTIVE: The purpose of this study was to determine the correlation between transcranial Doppler (TCD) velocities and angiographic vasospasm after aneurysmal subarachnoid hemorrhage. METHODS: In the first part of this study, patients were retrospectively reviewed to correlate middle cerebral artery absolute blood flow velocities with angiographic vasospasm. In the second part of the study, the middle cerebral artery/ipsilateral extracranial internal carotid artery velocity ratio (Lindegaard ratio) was prospectively correlated with angiographic vasospasm. Angiographic vasospasm was independently graded, by observers blinded to the TCD results, as either none, mild (less than one-third artery luminal narrowing), moderate (one-third to one-half narrowing), or severe (more than one-half narrowing). The sensitivity, specificity, likelihood ratios for positive and negative TCD results, positive and negative predictive values, and kappa and P values were calculated. RESULTS: One hundred one patients were analyzed in the first part of the study, and 44 patients were analyzed in the second part. Interobserver agreement regarding angiographic vasospasm was good (kappa = 0.86). Despite significant correlation between mean velocities and the degree of vasospasm, the clinical dependability of TCD velocities (evaluated using predictive values and likelihood ratios) was limited. The positive predictive value of velocities of > or =200 cm/s for moderate/severe angiographic vasospasm was 87% but that of lower velocities was approximately 50%. The negative predictive value of velocities of <120 cm/s was 94% but that of higher velocities was approximately 75%. Only the likelihood ratios for velocities of <120 or > or =200 cm/s were useful (likelihood ratio for negative result = 0.17, likelihood ratio for positive result = 16.39). Overall, 57% of patients exhibited maximum velocities in the indeterminate range between 120 and 199 cm/s. Lindegaard ratios did not improve the predictive value of TCD monitoring. CONCLUSION: For individual patients, only low or very high middle cerebral artery flow velocities (i.e., <120 or > or =200 cm/s) reliably predicted the absence or presence of clinically significant angiographic vasospasm. Intermediate velocities, which were observed for approximately one-half of the patients, were not dependable and should be interpreted with caution.

Intraventricular thrombolysis speeds blood clot resolution: Results of a pilot, prospective, randomized, double-blind, controlled trial

OBJECTIVEAnimal models and clinical studies suggest that intraventricular thrombolysis improves clot resolution and clinical outcomes among patients with intraventricular hemorrhage. However, this intervention may increase the rates of rebleeding and infection. To assess the safety and efficacy of intraventricular thrombolysis, we conducted a pilot, randomized, double-blind, controlled, multicenter study. METHODSPatients with intraventricular hemorrhage requiring ventriculostomy were randomized to receive intraventricular injections of normal saline solution or urokinase (25,000 international units) at 12-hour intervals. Injections continued until ventricular drainage was discontinued according to prespecified clinical criteria. Head computed tomographic scans were obtained daily, for quantitative determinations of intraventricular hemorrhage volumes. The rate of clot resolution was estimated for each group. RESULTSTwelve subjects were enrolled (urokinase, seven patients; placebo, five patients). Commercial withdrawal of urokinase precluded additional enrollment. The urokinase and placebo groups were similar with respect to age (49.6 versus 55.2 yr, P = 0.43) and presenting Glasgow Coma Scale scores (7.14 versus 8.00, P = 0.72). Randomization to the urokinase treatment arm (P = 0.02) and female sex (P = 0.008) favorably affected the clot resolution rate. The sex-adjusted clot half-life for the urokinase-treated group was reduced 44.6%, compared with the value for the placebo group (4.69 versus 8.48 d). CONCLUSIONIntraventricular thrombolysis with urokinase speeds the resolution of intraventricular blood clots, compared with treatment with ventricular drainage alone.

CT Angiography for the Detection and Characterization of Carotid Artery Bifurcation Disease

Background and Purpose Computed tomographic angiography (CTA) is a relatively new and minimally invasive method of imaging intracranial and extracranial blood vessels. The main purpose of this study was to compare CTA to the current gold standard of arterial imaging, digital subtraction angiography (DSA), for the detection and quantification of carotid artery bifurcation stenosis. We also compared Doppler ultrasound (US) with these 2 techniques. Methods In a prospective study, 40 patients (80 carotid arteries) underwent CTA, US, and DSA. Patients chosen for inclusion were symptomatic with TIAs or stroke and had initial US screening that indicated >50% carotid stenosis on the side appropriate for the symptoms. Source axial, maximum intensity projection (MIP), and shaded-surface display (SSD) images were produced for each CTA study. The US, CTA, and DSA images were reviewed, with the degree of stenosis quantified and presence of ulcers determined; each type of imaging was reviewed by a separate investigator blinded to the results of the other 2 modalities. The results of CTA and US imaging were compared with the DSA images for degrees of carotid stenosis. Results CTA source axial images correlated with DSA more closely than MIP or SSD images for all degrees of stenosis. The correlation between US and DSA (0.808) was poorer than that between CTA and DSA (0.892 to 0.922). CTA performed well in the detection of mild (0% to 29%) carotid stenosis, as well as carotid occlusion, with values for sensitivity, specificity, and accuracy near 100%. In determining that a stenosis was >50% by DSA measurement, CTA was again useful, with a sensitivity, specificity, and accuracy of 89%, 91%, and 90%, respectively. While CTA was quite specific and accurate in identifying degrees of stenoses in either the 50% to 69% or the 70% to 99% ranges, in this task it was much less sensitive: 65% for 50%–69% stenosis and 73% for 70%–99% stenosis. These results did not change significantly when only the data from the most clinically relevant symptomatic arteries were analyzed. CTA was found to correlate quite well with DSA in the detection of ulcers associated with the carotid stenosis. Conclusions CTA was found to be an excellent examination for the detection of carotid occlusion and categorization of stenosis in either the 0%–29% or >50% ranges. However, CTA was unable to reliably distinguish between moderate (50%–69%) and severe (70%–99%) stenosis, which is an important limitation in the investigation and treatment of carotid stenosis.

Recombinant activated factor VII for the rapid correction of coagulopathy in nonhemophilic neurosurgical patients.

OBJECTIVECoagulopathy is a significant contraindication for neurosurgery. Unfortunately, many coagulopathic patients require urgent neurosurgical intervention. Standard use of blood products, including fresh-frozen plasma or prothrombin complexes, to correct the coagulopathy often leads to significant delays in treatment. Recombinant activated factor VII (rFVIIa) is a medication originally designed to treat bleeding in hemophiliacs but also seems to correct a wide variety of coagulopathies rapidly and safely in nonhemophilic patients. METHODSThe medical records of nine patients with coagulopathy requiring urgent neurosurgical intervention were reviewed retrospectively. Each patient was given a dose ranging from 40 to 90 &mgr;g/kg of rFVIIa before undergoing surgery. Pre-rFVIIa coagulation and post-rFVIIa coagulation parameters were obtained. Once correction of the coagulopathy was verified, each patient underwent the appropriate neurosurgical procedure. RESULTSThe average age of the patients was 40.9 years; six were women. The causes of the coagulopathy included anticoagulant medication, liver dysfunction, and dilutional coagulopathy after traumatic hemorrhage. Neurosurgical indications included intraparenchymal/intraventricular hemorrhage, hydrocephalus, diffuse cerebral edema, and epidural hematoma. Post-rFVIIa coagulation parameters obtained as early as 20 minutes after infusion of the medication showed normalization of values. There were no procedural or operative complications and no postoperative hemorrhagic complications. No associated thromboembolic or other complications with the use of rFVIIa were observed. CONCLUSIONThe use of rFVIIa for the urgent surgical treatment of coagulopathic patients is quite promising. Further studies, including randomized, prospective trials using rFVIIa to address issues such as optimal dosing, efficacy, surgical indications, cost-effectiveness, morbidity, and mortality are needed.

Hyperperfusion Syndrome: Toward a Stricter Definition

OBJECTIVEHyperperfusion syndrome is a rare and potentially devastating complication of carotid endarterectomy or carotid artery angioplasty and stenting. With the advent of new imaging techniques, we reviewed our experience with this phenomenon. METHODSThis report is a retrospective review of 129 consecutive cases of carotid endarterectomy performed between June 1, 2000, and May 31, 2002, and 44 consecutive cases of carotid artery angioplasty and stenting performed between January 1, 1997, and May 31, 2002. We specifically searched for examples of patients who developed postprocedural nonthrombotic neurological deficits that typified the hyperperfusion syndrome. RESULTSSeven cases of hyperperfusion syndrome occurred, four after endarterectomy (3.1% of carotid endarterectomy cases) and three after stenting (6.8% of stenting cases). The cases of hyperperfusion were classified as presenting with 1) acute focal edema (two cases with stroke-like presentation, attributable to edema immediately after revascularization), 2) acute hemorrhage (two cases of intracerebral hemorrhage immediately after stenting and one case immediately after endarterectomy), or 3) delayed classic presentation (two cases with seizures, focal motor weakness, and/or late intracerebral hemorrhage at least 24 hours after endarterectomy). CONCLUSIONHyperperfusion syndrome may be more common and more variable in clinical presentation than previously appreciated.

Treatment of intraventricular hemorrhage with tissue plasminogen activator.

The patients with intraventricular hemorrhage (IVH) were treated with recombinant tissue plasminogen activator (rt-PA) injected directly into the lateral ventricles, followed by ventricular drainage. All had a decreased level of consciousness before treatment (Glasgow Coma Scale score 10 +/- 3.4). A total dose between 2 and 12 mg of rt-PA (6.4 +/- 3.3) was administered. For eight patients with aneurysmal IVH, treatment with rt-PA began with two patients the same day as the aneurysm clipping, and the day after with six patients. For a patient with an excision of a ruptured arteriovenous malformation and a patient with IVH resulting from a lateral ventricular catheterization during posterior fossa tumor surgery, treatment with rt-PA started 24 hours after surgery. After an injection of rt-PA, the ventricular drain was closed for 1 hour, followed by alternate-hourly drainage and intracranial pressure (ICP) monitoring. Five patients received a second injection of rt-PA on the second postoperative day, and one patient received a third dose on the third day. Among the eight patients given rt-PA the day after surgery, the volume of external cerebrospinal fluid (CSF) drainage for 24 +/- 8 hours before treatment was 61 +/- 57 ml, and the mean ICP was 22 +/- 5 mm Hg during this same time. Younger age and poorer neurological condition correlated with higher ICP before treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional Performance of Carotid Endarterectomy Appropriateness, Outcomes, and Risk Factors for Complications

BACKGROUND AND PURPOSE Guided by the findings of randomized controlled trials evaluating carotid endarterectomy (CEA), we examined the appropriateness of CEAs performed in our city and determined the incidences and risk factors for postoperative stroke, death, and cardiac complications. METHODS Using health records, we retrospectively reviewed 291 consecutive CEAs performed in our region over 18 months. Based on randomized controlled trial results and standardized remeasurements of angiographic carotid stenoses, indications for CEA were considered appropriate for symptomatic carotid stenoses > or = 70%, uncertain for < 70% symptomatic or > or = 60% asymptomatic stenoses, or inappropriate for < 60% asymptomatic stenoses and for patients with preoperative neurological or medical instability. RESULTS We found that 41% of patients (118/291) were asymptomatic. Surgical indications were appropriate in 33% of cases (92/281), uncertain in 49% (138/281), and inappropriate in 18% (51/281). Stroke or death occurred within 30 days postoperatively in 5.2% (9/174) of symptomatic patients and 5.1% (6/117) of asymptomatic patients. At least one cardiac complication (angina, congestive heart failure, dysrhythmia, or myocardial infarction) developed in 8.9% (26/291). Independent preoperative risk factors for stroke or death were histories of angina or congestive heart failure and lack of antiplatelet medication; for cardiac complications, risk factors were age > 75 years and a history of congestive heart failure. CONCLUSIONS Almost 1 in 5 patients underwent CEA inappropriately, which was most commonly due to apparent over-estimation of stenosis severity, and half had uncertain indications. Our high complication rate possibly negated any overall surgical benefit in the large group of asymptomatic patients.

Experience with computed tomographic angiography for the detection of intracranial aneurysms in the setting of acute subarachnoid hemorrhage.

OBJECTIVE To objectively compare computed tomographic angiography (CTA) with selective digital subtraction angiography (DSA) in the detection and anatomic definition of intracranial aneurysms, particularly in the setting of acute subarachnoid hemorrhage (SAH). METHODS In a blinded prospective study, 40 patients with known or suspected intracranial saccular aneurysms underwent both CTA and DSA, including 32 consecutive patients with SAH in whom CTA was performed after CT images were obtained diagnostic for SAH. The CT angiograms were interpreted for presence, location, and size of the aneurysms, and anatomic features, such as the number of aneurysms lobes, aneurysm neck size (< or = 4 mm), and the number of adjacent arterial branches were suggested. The images obtained with CTA were then compared with the images obtained with DSA, with the later images serving as controls. RESULTS DSA revealed 43 aneurysms in 30 patients and ruled out intracranial aneurysms in the remaining 10 patients. For aneurysm presence alone, the sensitivity and specificity for CTA was 86 and 90%, respectively. For the presence of an aneurysms, six CT angiogram showed false negative results and one CT angiogram showed a false positive result. False negative results were usually caused by technical problems with the image, tiny aneurysm domes (< 3 mm), and unusual aneurysm locations (i.e., intracavernous carotid or posterior inferior cerebellar artery aneurysms). The results obtained with CTA were, compared with the results obtained with DSA, more than 95% accurate in determining dome and neck size of aneurysm, aneurysm lobularity, and the presence and number of adjacent arterial branches. In addition, CTA provided a three-dimensional representation of the aneurysmal lesion, which was considered useful for surgical planning. CONCLUSION CTA is useful for rapid and relatively noninvasive detection of aneurysms in common locations, and the anatomic information provided in images showing positive results is at least equivalent to that provided by DSA. In cases of SAH in which the nonaugmented CT and CTA results indicate a clear source of bleeding and provide adequate anatomic detail, we think it is possible to forego DSA before urgent early aneurysm surgery. In all other cases, DSA is indicated.

Hemodynamic Instability after Carotid Endarterectomy: Risk Factors and Associations with Operative Complications

OBJECTIVE To examine the incidences of hypertension, hypotension, and bradycardia after carotid endarterectomy (CEA) and to identify any hemodynamic variables predictive of postoperative stroke, death, or cardiac complications. METHODS Retrospective population-based cohort study of 291 consecutive patients undergoing CEA using hospital chart review. Hemodynamic data collected from time of arrival in the recovery room until the end of the 1st postoperative day. Primary and secondary outcome events were stroke or death within 30 days of surgery and any postoperative cardiac complication (angina, congestive heart failure, dysrhythmia, or myocardial infarction), respectively. RESULTS The incidences of postoperative hypertension (systolic blood pressure > 220 mm Hg), hypotension (systolic blood pressure < 90 mm Hg), and bradycardia (pulse < 60 beats/min) were 9% (26 of 290 cases), 12% (36 of 290 cases), and 55% (159 of 290 cases), respectively. The stroke or death rate was 5.2% (15 of 291 cases). Postoperative hypertension was associated significantly with stroke or death (P = 0.04) and by a statistical trend with cardiac complications (P = 0.07). Independent preoperative risk factors for postoperative hypertension by multivariate analysis included angiographic intracranial carotid stenosis greater than 50%, cardiac dysrhythmia, preoperative systolic blood pressure greater than 160 mm Hg, neurological instability, and renal insufficiency. Postoperative hypotension and bradycardia did not correlate with primary or secondary outcomes. CONCLUSION Hemodynamic instability was commonly observed after CEA, but only postoperative hypertension was associated with stroke or death and, possibly, with cardiac complications. Patients undergoing CEA, especially those at risk for postoperative hypertension, may be monitored best in settings suited to the expeditious management of neurological and cardiovascular emergencies.

Combined microneurosurgical and thoracoscopic removal of neurogenic dumbbell tumors

The resection of posterior mediastinal dumbbell tumors has until now required laminectomy and some form of open access to the thoracic cavity. Over a 1-year period, a novel surgical approach combining posterior microneurosurgical and anterior video-assisted thoracoscopy techniques was used in 4 patients. In 3 patients, the tumor was removed successfully with minimal postoperative discomfort and rapid recovery. In the fourth patient, limited thoracotomy became necessary to control bleeding. This new approach, which combines modern-day neurosurgical and general thoracic surgical techniques, appears safe and could become the preferred method for removing most benign posterior mediastinal dumbbell tumors.