40 Endovascular Treatment of Cerebral Venous Thrombosis
40.1 Case Description
40.1.1 Clinical Presentation
A 23-year old woman presented to the emergency room of a community hospital with confusion and a 2-day history of severe headache. At examination, she had a score of 12 on the Glasgow Coma Scale (GCS) and mild left-sided weakness. Shortly after admission, she developed epileptic seizures, became comatose, and developed a fixed and dilated right pupil. She was then sedated, intubated, and transferred to our hospital.
40.1.2 Baseline Imaging
Noncontrast CT (NCCT) showed bilateral areas of edema in the frontal lobes, mostly subcortical and more pronounced in the right hemisphere. Within the lesions were patchy areas of hemorrhage. There was mass effect and a midline shift of 6 mm. The right transverse and sigmoid sinus demonstrated a region of hyperdensity, and a cord sign was visible in one of the cortical veins (Fig. 40.1).
MRI confirmed the presence of bilateral hemorrhagic infarctions. Contrast-enhanced MR venography showed thrombosis of the anterior part of the superior sagittal sinus, and nonocclusive thrombi in the posterior part of the superior sagittal sinus, right transverse sinus, and right sigmoid sinus. The cortical veins overlaying the frontal lobes were also thrombosed. The left internal jugular vein was hypoplastic (Fig. 40.2).
Cerebral venous thrombosis with bilateral hemorrhagic infarctions.
Because of clinical and radiological signs of impending transtentorial and subfalcine herniation, the patient underwent emergency bilateral decompressive hemicraniectomy and placement of an external ventricular drain. Prior to surgery, she had a GCS score of 4 and bilateral fixed and dilated pupils.
Immediately after the operation, she was transferred to the angio suite for mechanical thrombectomy (Fig. 40.3). Balloon angioplasty was performed using a 7 × 20 mm Amiia balloon. Successful recanalization of the right transverse sigmoid and sigmoid sinus was achieved, and flow was improved in the posterior third of the superior sagittal sinus. Recanalization of the anterior part of the superior sagittal sinus was attempted with a 3.5 × 10 mm balloon, but was unsuccessful.
NCCT after the bilateral hemicraniectomy and thrombectomy demonstrated a decrease in mass effect. The hemorrhagic component of the venous infarcts had increased, most likely as a result of the decrease in intracranial pressure (Fig. 40.4).
After the surgical and endovascular procedure, the patient was started on unfractionated heparin in the therapeutic dose.
Initially, after the interventions, the clinical condition of the patient was unchanged, but after an extended stay in the intensive care unit (ICU), she began to improve.
Two months after admission, she was discharged to a rehabilitation clinic on warfarin and antiseizure medication. She continued to improve and was discharged home several weeks later. Cranioplasty was performed approximately 1 year after initial admission.
The patient continued to improve clinically and at her last follow-up visit, 5 years after admission, she had no focal neurological deficits. She followed a part-time education for a legal profession. She did develop epilepsy over time, which was controlled with levetiracetam, carbamazepine and clobazam. Apart from oral contraceptive use, no cause for the thrombosis was identified.
CT scan at follow-up showed encephalomalacia in both frontal lobes, predominantly in the white matter (Fig. 40.5). Contrast-enhanced MR venography performed about 18 months after admission showed that the anterior part of the superior sagittal sinus had recanalized (Fig. 40.6).
Cerebral venous thrombosis (CVT) is a rare cause of stroke that mainly affects young adults and children. 1 , 2 In adults, women are affected three times more often than men, which is the result of hormonal risk factors (oral contraceptives and pregnancy). 3 The most common clinical manifestations of CVT are headache (90%), focal neurological deficits (50%), and epileptic seizures (40%). Approximately 40 to 60% of patients have a brain parenchymal lesion on imaging, usually in the form of a venous hemorrhagic infarct. 4 , 5 Coma at admission, as was the case in our patient, occurs in less than 5% of patients and is usually caused by mass effect from large venous infarcts, bilateral edema of the thalami and basal ganglia, or recurrent seizures.
The standard treatment of CVT is anticoagulation with heparin, either with unfractionated or low-molecular weight heparin, and this therapy should be initiated as soon as possible after the diagnosis is established. 6 , 7 , 8 , 9 In our patient, heparin was not started immediately because emergency neurosurgical intervention was required. Transtentorial herniation is the most important cause of early death in patients with CVT, and recent data suggest that decompressive hemicraniectomy can be lifesaving and result in good functional outcomes in these patients. 10 , 11 , 12 Our patient was in a very severe condition prior to surgery, with bilateral fixed and dilated pupils, but even in these patients, good recovery has been reported. 13
The use of endovascular treatment (ET) in patients with CVT is increasingly reported in the literature. Most of these studies report good outcomes; however, almost all of them are case reports or small case series. 14 , 15 , 16 It is difficult to draw any conclusions on the basis of these data, because of the high risk of publication bias and the fact that the prognosis of CVT is also favorable in many patients who do not undergo ET. 3 , 17 Thus far, no controlled studies have been performed, although there is one ongoing randomized trial, the TO-ACT trial. 18 In this study, patients with CVT and a high risk of poor outcome are randomized to standard therapy or standard therapy in combination with ET. The trial has a pragmatic design and does not prescribe a specific endovascular method. Instead, the interventionalist can use the strategy that he/she thinks is best suited for that particular case. Intrasinus thrombolysis (using recombinant tissue plasminogen activator [rtPA] or urokinase), mechanical thrombectomy, or a combination of both can be used. The results of the TO-ACT trial were presented at the European Stroke Conference. Among 67 randomized patients, ET did not improve clinical outcome over standard therapy. The full results of the study are expected to be published this year.
In the absence of trial data on its efficacy and safety in CVT, the decision to use ET must be weighed in each separate case. The guideline of the American Heart Association advises to reserve ET for patients who deteriorate despite heparin treatment, or if patients who develop mass effect from a venous infarction that causes intracranial hypertension are resistant to standard therapies. 6 If ET is done in a patient with impending herniation, it is important that it is preceded by decompressive surgery. ET alone is insufficient to reverse the process of herniation and in the absence of decompressive surgery, there is a high risk of fatal herniation while the patient is under anesthesia for the intervention. 19 , 20
Judging from the number of publications in recent years, mechanical thrombectomy is currently favored over intrasinus thrombolysis, despite the fact that there is no evidence that one technique is superior over the other. 21 Theoretically, the risk of hemorrhagic complications is lower with mechanical thrombectomy, because of the obvious risk of using a thrombolytic drug in a condition where most patients already have an intracerebral hemorrhage prior to the intervention. On the other hand, devices that are used for mechanical thrombectomy are generally more bulky, which could increase the risk of perforating a sinus. The Angiojet device, for example, is frequently used in ET for CVT, but a recent systematic review suggested that it is associated with a higher risk of complications and a lower chance of successful recanalization. 22
In our case, ET was partially successful. We managed to recanalize the posterior part of the superior sagittal sinus and the dominant transverse and sigmoid sinus. The venous outflow was also substantially improved after the procedure; however, we did not succeed in recanalizing the anterior part of the superior sagittal sinus. After two attempts, we decided not to pursue this any further for the following reasons: (1) risk of hemorrhagic complications and (2) the cortical veins in that region were all thrombosed, and even if we would managed to open the sinus, the flow in the cortical veins could not be restored with ET.
In summary, ET can be considered in patients with a severe form of CVT, but currently there is insufficient evidence on its efficacy and safety from controlled studies. Analysis of the full results of the TO-ACT trial may help in delineating the role of ET in the treatment of CVT.