Abstract WP174: Frequency, Predicators, and Outcomes of Pre-Intervention Thrombus Migration in Patients With Acute Ischemic Stroke Due to Large Vessel Occlusion

Background: In patients presenting with acute ischemic stroke (AIS) due to large vessel occlusion (LVO), between initial CTA/MRA and catheter angiography performed for intervention, the occlusive thrombus may persist unchanged, fragment and migrate distally, or resolve completely, with or without bridging intravenous fibrinolytic treatment. The frequency, predictors, and outcomes of pre-intervention thrombus migration not been well delineated.

Methods: We analyzed a prospectively maintained registry of AIS-LVO patients at an academic medical center over a 2.8 year period (Dec 2014-Oct 2017). Comparing occlusion sites on arrival CTA/MRA with immediately following interventional angiogram, patients were classified as having: 1) thrombus persistence (TP), 2) thrombus migration (TM), or 3) thrombus resolution (TR).

Results: In the 220 patients, mean age was 70.7, 42.7% were female, NIHSS was 13.8, onset to first imaging was 156 minutes, and initial occlusion sites on MRA/CTA were: ICA-20.5%; MCA-67.3%; VA/BA-12.3%. Frequencies of thrombus evolution patterns were: TP-59.5%; TM-30.5%; TR-10.0%. On multivariate analysis, independent predictors of TM were: higher NIHSS (OR 1.06 per 1 pt), cardioembolic mechanism (OR 2.40), and longer time from last known well to first CTA/MRA imaging (OR 1.08 per 60 min). While rates of substantial reperfusion (TICI 2b-3) were similar (85.2% vs 83.7%), patients with TM rather than TP had lower rates of excellent reperfusion (TICI 2C-3), 24.1% vs 44.2%, p = 0.02. Symptomatic intracranial hemorrhage occurred more often in TM than TP, 17.9% vs 8.4%, p = 0.05. In multivariate analysis, TM was independently associated with reduced rates of good functional outcome (mRS 0-2), both at discharge (OR 0.41, 95% CI 0.19 to 0.90; p=0.03) and at 3 months (OR 0.43, 95% CI 0.19 to 0.94; p=0.03).

Conclusions: Early TM between initial noninvasive imaging and interventional angiography occurs in nearly one-third of patients, is paradoxically associated with poorer outcomes, including more symptomatic hemorrhage and reduced final functional independence. Better understanding of dynamic clot changes early after arrival and their effects on outcome may aid further development of reperfusion therapeutics.

A review of the diagnosis and management of vertebral basilar (posterior) circulation disease

We have reviewed the English literature published in the last 70 years on Diseases of the Vertebral Basilar Circulation, or Posterior Circulation Disease (PCD). We have found that errors have been made in the conduct and interpretation of these studies that have led to incorrect approaches to the management of PCD. Because of the difficulty in evaluating the PC, the management of PCD has been incorrectly applied from anterior circulation disease (ACD) experience to PCD. PCD is a common form of stroke affecting 20-40% patients with stroke. Yet, the evidence is strong that the Anterior Circulation (AC) and Posterior Circulations (PC) differ in their pathology, in their clinical presentations, in the rapidity of development of symptoms, in optimal imaging methods, and in available treatments. There appears to be two categories of patients who present with PCD. The first, acute basilar artery occlusion has a more rapid onset. The diagnosis must be made quickly and if imaging proves a diagnosis of Basilar Artery Occlusion (BAO), the treatment of choice is Interventional removal of the basilar artery thrombosis or embolus. The second category of PCD and the most commonly seen PCD disease process presents with non-specific symptoms and early warnings of PCD that now can be related to ischemic events in the entire PC vessels. These warning symptoms and signs occur much earlier than those in the AC. IA angiography is still the gold standard of diagnosis and is superior in definition to MR and CT angiography which are commonly used as a convenient screening imaging tool to evaluate PCD but are both inferior to IA angiography in definition for lesions below 3-4 mm. In at least two reported studies 7T MR angiography appears superior to other imaging modalities and will become the gold standard of imaging of PCD in the future. Medical treatments applied to the ACD have not been proven of value in specific forms of PCD. Interventional therapy was promising but of unproven value in Randomized Controlled Trials (RCT) except for the treatment of Basilar Artery Occlusion (BAO). Surgical revascularization has been proved to be highly successful in patients, who are refractory to medical therapy. These studies have been ignored by the scientific community basically because of an incorrect interpretation of the flawed EC-IC Bypass Trial in 1985 as applying to all stroke patients. Moreover, the EC-IC Bypass Study did not include PCD patients in their study population, but the study results were extrapolated to patients with PCD without any scientific basis. This experience led clinicians to an incorrect bias that surgical treatments are of no value in PCD. Thus, incorrectly, surgical treatments of PCD have not been considered among the therapeutic possibilities for PCD. QMRA is a new quantitative MR technique that measures specific blood flow in extra and intracranial vessels. QMRA has been used to select those patients who may benefit from medical, or interventional, or surgical treatment for PCD based on flow determinations with a high success rate. QMRA accurately predicts the flows in many large and small vessels in the PC and AC and clearly indicates that both circulations are intimately related. From medical and surgical studies, the longer one waits for surgical treatment the higher the risk of a poor outcome results. This observation becomes obvious when the rapidity of development of PCD is compared with ACD. Recent advances in endovascular therapy in the treatment of acute basilar thrombosis is a clear sign that early diagnosis and treatment of PCD will reduce the morbidity and mortality of these diseases. In this review it is evident that there are multiple medical and surgical treatments for PCD depending upon the location of the lesion(s) and the collateral circulation demonstrated. It is clear that the AC and PC have significant differences. With the exception of the large population studies from Oxford England, the reported studies on the management of PCD in the literature represent small selected subsets of the universe of PC diseases, the information from which is not generalizable to the universe of PCD patients. At this point in the history of PCD, there are not large enough databases of similar patients to provide a basis for valid randomized studies, with the exception of the surgical studies. Thus, a high index of suspicion of the early warning symptoms of PCD should lead to a rapid individual clinical assessment of patients selecting those with PCD. Medical, interventional, and/or surgical treatments should be chosen based on knowledge presented in this review. Recording the results in a national Registry on a continuing basis will provide the data that may help advance the management of PCD based on larger data bases of well documented patient information to guide the selection of future therapies for PCD treatments. It is also clear that the management of patients within the complex of diseases that comprise PCD should be performed in centers with expertise in the imaging, medical, interventional and surgical approaches to diseases of the PCD.

Cerebral Metabolism and the Role of Glucose Control in Acute Traumatic Brain Injury

This article reviews key concepts of cerebral glucose metabolism, neurologic outcomes in clinical trials, the biology of the neurovascular unit and its involvement in secondary brain injury after traumatic brain insults, and current scientific and clinical data that demonstrate a better understanding of the biology of metabolic dysfunction in the brain, a concept now known as cerebral metabolic energy crisis. The use of neuromonitoring techniques to better understand the pathophysiology of the metabolic crisis is reviewed and a model that summarizes the triphasic view of cerebral metabolic disturbance supported by existing scientific data is outlined. The evidence is summarized and a template for future research provided.

CT-negative, MRI GRE-positive primary motor cortex contusion causing isolated foot drop

Background:

Isolated acute foot drop due to traumatic brain injury is exceedingly rare and is often misdiagnosed during initial evaluation. Here, we present the case of a patient who presented with left foot drop after falling off a bicycle.

Case Description:

The patient is a 55-year-old male who was mountain biking when he fell, hit his head, and lost consciousness. Neurologic examination of the left leg revealed foot drop, no sensory deficits, and 3+ reflexes at the knee and ankle with clonus. Electroencephalography, computed tomography (CT) of the head, magnetic resonance imaging (MRI) of the lumbar spine, and CT of the lower extremities were all negative. Only MRI of the brain with a gradient echo sequence revealed microhemorrhages focused around the right precentral gyrus. The patient underwent physical therapy, and by 3 months had regained full strength in his left leg.

Conclusion:

Central causes of foot drop are exceptionally rare, however, they should be considered in all cases of post-traumatic dorsiflexion paresis. The key to the accurate diagnosis is a high index of suspicion as well as thorough and careful physical examination including reflex and sensory testing. Selective imaging modalities such as MRI or CT can then be used to verify the diagnosis.