Ahmed E. Hussein

Quantitative assessment of parent vessel and distal intracranial hemodynamics following pipeline flow diversion

Background Pipeline embolization devices (PEDs) are commonly used for endovascular treatment of cerebral aneurysms but can be associated with delayed ipsilateral intraparenchymal hemorrhage. Although intra-aneurysmal hemodynamic changes have been studied, parent vessel and intracranial hemodynamics after PED use are unknown. We examine the impact of flow diversion on parent artery and distal intracranial hemodynamics. Method Patients with internal carotid cerebral aneurysms treated with PED who had flow volume rate, flow velocities, pulsatility index, resistance index, Lindegaard ratio, and wall shear stress (WSS) obtained after treatment using quantitative magnetic resonance angiography were reviewed. Means were compared between ipsilateral and contralateral internal carotid artery (ICA) and middle cerebral artery (MCA) using paired t tests. Results A total of 18 patients were included. Mean flow volume rate was lower in the ipsilateral versus contralateral ICA (p = 0.04) but tended to be higher in the ipsilateral versus contralateral MCA (p = 0.08). Lindegaard ratio was higher ipsilateral to the PED in diastole (p = 0.05). Although there was no significant difference in flow velocities, pulsatility or resistance indices, and WSS, the two cases in our cohort with hemorrhagic complications did display significant changes in MCA flows and MCA WSS. Conclusion PED placement appears to alter the elasticity of the stented ICA segment, with lower flows in the ipsilateral versus contralateral ICA. Conversely, MCA flows and MCA WSS are higher in the ipsilateral MCA among patients with hemorrhage after PED placement, suggesting the role of disrupted distal hemodynamics in delayed ipsilateral intraparenchymal hemorrhage.

Validation of cerebral arteriovenous malformation hemodynamics assessed by DSA using quantitative magnetic resonance angiography: preliminary study

Background The hemodynamic evaluation of cerebral arteriovenous malformations (AVMs) using DSA has not been validated against true flow measurements. Objective To validate AVM hemodynamics assessed by DSA using quantitative magnetic resonance angiography (QMRA). Materials and methods Patients seen at our institution between 2007 and 2016 with a supratentorial AVM and DSA and QMRA obtained before any treatment were retrospectively reviewed. DSA assessment of AVM flow comprised AVM arterial-to-venous time (A-Vt) and iFlow transit time. A-Vt was defined as the difference between peak contrast intensity in the cavernous internal carotid artery and peak contrast intensity in the draining vein. iFlow transit times were determined using syngo iFlow software. A-Vt and iFlow transit times were correlated with total AVM flow measured using QMRA and AVM angioarchitectural and clinical features. Results 33 patients (mean age 33 years) were included. Nine patients presented with hemorrhage. Mean AVM volume was 9.8 mL (range 0.3–57.7 mL). Both A-Vt (r=−0.47, p=0.01) and iFlow (r=−0.44, p=0.01) correlated significantly with total AVM flow. iFlow transit time was significantly shorter in patients who presented with seizure but A-Vt and iFlow did not vary with other AVM angioarchitectural features such as venous stenosis or hemorrhagic presentation. Conclusions A-Vt and iFlow transit times on DSA correlate with cerebral AVM flow measured using QMRA. Thus, these parameters may be used to indirectly estimate AVM flow before and after embolization during angiography in real time.

Neurosurgical Emergency Transfers: An Analysis of Deterioration and Mortality

BACKGROUND Neurological deterioration and mortality are frequent in neurosurgical patients transferred to tertiary centers, but the precise predictors leading to them are unclear. OBJECTIVE To analyze and quantify risk factors predicting deterioration and death in neurosurgery transfers. METHODS A consecutive review of all transfers with cranial pathology to a tertiary academic neurosurgery service was performed over a 2-year period. Risk factors including demographics, medical comorbidities, hydrocephalus, anticoagulant use, transfer diagnosis, Glasgow Coma Scale score, and transfer time were reviewed. RESULTS A total of 1429 transfers were studied, including 154 (10.8%) instances of neurological decline in transit and 99 mortalities (6.9%). On multivariate analysis, significant predictors of decline were hydrocephalus ( P = .005, odds ratio [OR] 2) and use of clopidogrel ( P = .003, OR 4.3), warfarin ( P = .004, OR 2.6), or other systemic anticoagulants ( P < .001, OR 10.1). Age ( P = .004), hydrocephalus ( P = .006, OR 2.1), renal failure ( P = .05, OR 2.3), and use of clopidogrel ( P = .003, OR 4.6) or warfarin ( P = .03, OR 2.3) were found to be predictive of death. Analysis by transfer diagnosis found patients with intracerebral hemorrhage had the highest incidence of mortality (12.7%, P = .003, OR 2). Patients who ultimately died were transferred faster than survivors, but this did not achieve significance. CONCLUSION Neurosurgery patients are vulnerable to deterioration in transit and exhibit several patterns predictive of mortality. Hydrocephalus, use of clopidogrel and warfarin, and intracerebral hemorrhage are each independently associated with elevated risk of deterioration and death.

Cerebral Arteriovenous Malformation Flow Is Associated With Venous Intimal Hyperplasia

Background and Purpose— The pathogenesis of venous intimal hyperplasia and venous outflow stenosis associated with cerebral arteriovenous malformation (AVM) draining veins is poorly understood. We sought to determine the relationship between maximum vein wall thickness and AVM flow. Methods— Patients who underwent AVM surgical resection and had flow measured before treatment using quantitative magnetic resonance angiography were retrospectively reviewed. Specimens were mounted on slides and stained with elastin special stain. Perinidal veins were identified, and maximum wall thickness was measured from digitized images. Relationship between maximum vein wall thickness and AVM flow was assessed. Results— Twenty-eight patients were included. Spearman correlation revealed a statistically significant relationship between maximum vein wall thickness and total AVM flow (&rgr;=+0.51; P=0.006), AVM flow per draining vein (&rgr;=+0.41; P=0.03), and mean intranidal vessel diameter (&rgr;=+0.39; P=0.04). Conclusions— Maximum vein wall thickness increases with higher total AVM flow and AVM flow per draining vein. This finding implicates chronically high AVM inflow in venous intimal hyperplasia.

Reducing length of stay in aneurysmal subarachnoid hemorrhage: A three year institutional experience

Hospital length of stay is a common metric of excellence in health care. With limited data evaluating hospital length of stay (LOS) and cost in subarachnoid hemorrhage (SAH), in this study we explore multiple prognostic factors and present our institutional experience in shortening LOS. 345 SAH patients were reviewed over a three year period. Patient demographics, hemorrhage grade, hospital course, hospital costs, and LOS were reviewed. Angiogram-negative SAH, Hunt and Hess (HH) Grade 5, and early mortalities were excluded. During this period a physician-led daily multidisciplinary huddle was established to identify and expedite patient discharge needs. 174 patients met inclusion criteria. Significant predictors of increased hospital LOS on univariate analysis included higher HH grade, hydrocephalus, need for ventriculostomy or ventriculoperitoneal shunt, clinical vasospasm, pneumonia, respiratory failure, deep venous thrombosis, and urinary tract infection. Need for shunt, clinical vasospasm, and pneumonia remained significant on multivariate analysis. Mean LOS times decreased to less than those cited in earlier studies, with mean hospital LOS dropping from 21.6days to 14.1. Total hospital costs per SAH patient decreased from

Aneurysm size and the Windkessel effect: An analysis of contrast intensity in digital subtraction angiography

328K to

O-041 The Aneurysm Size and Windkessel Effect: A Contrast Transit Times Study on Digital Subtraction Angiography

269K. Readmission rate and breakdown by patient discharge site remained unchanged. Need for ventriculoperitoneal shunt, clinical vasospasm, and pneumonia were found predictive of longer LOS in SAH patients. A physician-led daily multidisciplinary huddle is a potentially valuable tool to identify patient discharge needs and lower LOS and cost in SAH patients.

Contrast Time-Density Time on Digital Subtraction Angiography Correlates With Cerebral Arteriovenous Malformation Flow Measured by Quantitative Magnetic Resonance Angiography, Angioarchitecture, and Hemorrhage

Large cerebral aneurysms are considered more dangerous than their smaller counterparts, with higher risk of subarachnoid hemorrhage. Understanding the hemodynamics of large aneurysms has potential to predict their response to treatment. Digital subtraction angiography images for patients with intracranial aneurysms over a seven-year period were reviewed. Unruptured solitary aneurysms of the internal carotid artery (ICA) proximal to the terminus and posterior communicating artery were included. Contrast intensity over time was analyzed at the center of the M1 segment of the middle cerebral artery distal to the aneurysm and compared to the contralateral side. Analysis included time to peak (TP)10%–100% (time needed for contrast to change from 10% intensity to 100%), washout time (WT)100%–10% (time for 100% intensity to 10%), and quartile time (QT)25%–25% (time for 25% intensity during vessel filling to 25% during emptying). Fifty patients met the inclusion criteria. Analysis over the ipsilateral M1 segment revealed a significant increase in QT25%–25% (8.5 vs 7.6 seconds, p = 0.006) compared to the contralateral side. There was a correlation between TP10%–100% and QT25%–25% with aneurysm size (Pearson’s r = 0.37, p = 0.007 and r = 0.43, p = 0.001, respectively). Larger ICA aneurysms were associated with delayed contrast intensity times. A plausible mechanism is that large aneurysms act as a capacitance chamber (Windkessel effect) that slow the arrival of contrast distal to the aneurysm. This may be of significance for large aneurysms after treatment, where the loss of the Windkessel effect places the distal circulation at greater risk for hemorrhage, and warrants further study.

Cerebral Aneurysm Size and Distal Intracranial Hemodynamics: An Assessment of Flow and Pulsatility Index Using Quantitative Magnetic Resonance Angiography

Introduction Treatment of large and giant intracranial aneurysms are often associated with larger complications rates, related to hemodynamic changes of intracranial flow distal to the intracranial aneurysms. In this paper we evaluated the baseline contrast transit times on angiography for patients with proximal anterior circulation aneurysms. Methods Medical charts and digital subtraction angiographic (DSA) films for patients with intracranial aneurysms were reviewed. Only proximal, unruptured anterior circulations aneurysms were included. DSA images were analyzed over M1 segment, using custom made software for the time-density. Analysis included TT10% – 100% (time needed for the contrast to change from 10%–100% image intensity), TT100%–10% (time needed for the contrast to change from 100%–10% image intensity), and TT25% – 25% (time needed for the contrast to change from 25%–25% image intensity. This was compared to the contralateral M1 transit times. Results A total of 50 patients were included in this study. Aneurysm size ranged from 2–40 mm, mean 12 mm. Analysis over the M1 segment showed a significant increase in the TT25%–25% (7.6 to 8.46 seconds, P = 0.006) compared to the contralateral side. There was significant correlation (Spearman’s correlation) between the TT10%–100%, the TT25%–25% and the aneurysm size (rho = 0.291, 0.362 and P = 0.041, 0.01 respectively) (Figure 1), indicating a slower contrast time in larger aneurysms. Similarly, there was significant correlation between the absolute difference between the ipsilateral and contralateral TTs and aneurysm size (TT10%–100% : P = 0.005, rho = 0.393; TT25%–25% : P < 0.001, rho = 0.52) (Figure 2).Abstract O-041 Figure 1Abstract O-041 Figure 2 Conclusion Our analysis shows that statistically significant difference in the intracranial contrast TT as a function of proximal aneurysm size. The mechanism for this might be related to the Windkessel effect where the aneurysm as a blood reservoir in systole and partially release the contrast in diastole. Changes to this baseline phenomenon might contribute to complications post flow diverters implementation. Disclosures A. Hussein: None. A. Linninger: None. F. Charbel, II: None. C. Hsu: None. F. Charbel: 2; C; Transonic. 4; C; VasSol Inc. V. Aletich: 2; C; Codman. A. Alaraj: 2; C; Codman.

Motor Cortex Stimulation for Deafferentation Pain

BACKGROUND Digital subtraction angiography (DSA) currently provides angioarchitectural features of cerebral arteriovenous malformations (AVMs) but its role in the hemodynamic evaluation of AVMs is poorly understood. OBJECTIVE To assess contrast time‐density time (TT) on DSA relative to AVM flow measured using quantitative magnetic resonance angiography (QMRA). METHODS Patients seen at our institution between 2007 and 2014 with a supratentorial AVM and DSA and QMRA obtained prior to any treatment were retrospectively reviewed. Regions of interest were selected on the draining veins at the point closest to the nidus. TT on DSA was defined as time needed for contrast to change image intensity from 10% to 100%, 100% to 10%, and 25% to 25%. TT was correlated to AVM total flow, angioarchitectural features, and hemorrhage. RESULTS Twenty‐eight patients (mean age 35.6 yr) were included. Six patients presented with hemorrhage. Mean AVM volume was 11.42 mL (range 0.3‐57.7 mL). Higher total AVM flow significantly correlated with shorter TT100%‐10% and TT25%‐25% (P = .02, .02, respectively). Presence of venous stenosis correlated significantly with shorter TT100%‐10% (P = .04) and TT25%‐25% (P = .04). AVMs with a single draining vein exhibited longer TT25%‐25% compared to those with multiple draining veins (P = .04). Ruptured AVMs had significantly shorter TT10%‐100% compared to unruptured AVMs (P = .05). CONCLUSION TT on DSA correlates with cerebral AVM flow measured using QMRA and with AVM angioarchitecture and hemorrhagic presentation. Thus, TT may be used to indirectly estimate AVM flow during angiography in real‐time and may also be an indicator of important AVM characteristics associated with outflow resistance and increased rupture risk, such as venous stenosis.