A1 asynchrony, a potential risk factor for the rupture of anterior communicating artery aneurysms: A computational fluid dynamics study / Asincronía de A1, un factor de riesgo potencial para la rotura de aneurismas de la arteria comunicante anterior: un estudio de dinámica de fluidos computacional

Introduction and objectives: The anterior communicating complex is one the most common locations for aneurysm development. It receives blood from both carotid circulations and the effect of synchrony on the arrival of blood flow has not been previously studied. The objective of this study was to compare the asynchrony conditions of the A1 pulse and its effects on the haemodynamic conditions of anterior communicating artery (ACoA) aneurysms. Materials and methods: From 2008 to 2017, 54 anterior communicating artery aneurysms treated at our centre were included in the study. Computational fluid dynamics (CFD) techniques were employed and simulations consisted of complete conditions of synchrony and introducing a delay of 0.2s in the non-dominant A1 artery. Time-averaged wall shear stress (TAWSS), low shear area (LSA), A1 diameter and ACoA angles were measured. Results: The difference in the LSA in conditions of synchrony and asynchrony resulted in a broad range of positive and negative values. The symmetry index (p=0.04) and A1/A2 angle on the dominant artery (p=0.04) were associated with changes in LSA. Conclusions: In asynchrony, LSA increased in the absence of A1 asymmetry and low A1/A2 angles, potentially increasing the risk of aneurysm rupture in this location

Introducción y objetivos: El complejo comunicante anterior es una de las localizaciones más frecuentes para el desarrollo de aneurismas; recibe sangre de ambas circulaciones carotídeas y el efecto de la sincronía en la llegada de sangre no ha sido estudiado previamente. El objetivo de este estudio es comparar las condiciones de asincronía del pulso de A1 y sus efectos en las condiciones hemodinámicas de los aneurismas de la arteria comunicante anterior (ACoA). Materiales y métodos: Desde 2008 hasta 2017, 54 aneurismas de la ACoA tratados en nuestro centro se incluyeron en el estudio. Se emplearon técnicas de dinámica de fluidos computacional y las simulaciones consistieron en condiciones de completa sincronía y en la introducción de un retraso de 0,2s en la arteria A1 no dominante. Se realizaron mediciones del TAWSS, área de bajo cizallamiento (LSA), diámetros de A1 y ángulos de la AcoA. Resultados: La diferencia producida en el LSA en condiciones de sincronía y asincronía resultó en un amplio rango de valores positivos y negativos. El índice de simetría (p=0,04) y el ángulo A1/A2 en la arteria dominante (p=0,04) se relacionan con los cambios en el LSA. Conclusiones: En asincronía, el LSA se incrementó en ausencia de asimetría A1 y ángulos A1/A2 menores, incrementando potencialmente el riesgo de rotura de aneurismas en esta localización

A1 asynchrony, a potential risk factor for the rupture of anterior communicating artery aneurysms: A computational fluid dynamics study.

INTRODUCTION AND OBJECTIVES: The anterior communicating complex is one the most common locations for aneurysm development. It receives blood from both carotid circulations and the effect of synchrony on the arrival of blood flow has not been previously studied. The objective of this study was to compare the asynchrony conditions of the A1 pulse and its effects on the haemodynamic conditions of anterior communicating artery (ACoA) aneurysms. MATERIALS AND METHODS: From 2008 to 2017, 54 anterior communicating artery aneurysms treated at our centre were included in the study. Computational fluid dynamics (CFD) techniques were employed and simulations consisted of complete conditions of synchrony and introducing a delay of 0.2s in the non-dominant A1 artery. Time-averaged wall shear stress (TAWSS), low shear area (LSA), A1 diameter and ACoA angles were measured. RESULTS: The difference in the LSA in conditions of synchrony and asynchrony resulted in a broad range of positive and negative values. The symmetry index (p=0.04) and A1/A2 angle on the dominant artery (p=0.04) were associated with changes in LSA. CONCLUSIONS: In asynchrony, LSA increased in the absence of A1 asymmetry and low A1/A2 angles, potentially increasing the risk of aneurysm rupture in this location.

Hemodynamic Changes in the Treatment of Multiple Intracranial Aneurysms: A Computational Fluid Dynamics Study.

BACKGROUND: Intracranial aneurysm rupture is associated with a high mortality and disability despite modern medical care. Multiple aneurysms occur in nearly 16% of patients, and imaging studies of naturally occurring multiple aneurysms are valuable for computational fluid dynamics studies. In this study, we describe and analyze the hemodynamic changes produced in a distal aneurysm after the treatment of a proximal aneurysm. METHODS: Between January 2008 and December 2017, 24 cases of multiple intracranial aneurysms of the same vascular tree were treated in our center. Full carotid segmentations from digital subtraction angiography, computed tomography angiography, or magnetic resonance angiography were obtained, and transient pulsatile simulations were performed using computational fluid dynamics software. Output variables included maximum peak systole wall shear stress (WSS), minimum mid-diastolic WSS, maximum systolic pressure, low shear area, and high shear area both before and after treatment of the proximal aneurysm. RESULTS: The mean size of ruptured and unruptured aneurysms was 7.05 and 5.23 mm, respectively (P = 0.035), with respective aspect ratios of 1.22 and 2.04 (P = 0.001). Maximum peak systole WSS was lower and minimum mid-diastolic WSS was higher in unruptured aneurysms (P = 0.04 and 0.034, respectively). After treatment of the proximal aneurysm, low shear area in the distal aneurysm increased from 54.15% to 56.93% (P = 0.02). The opposite effect is noted in aneurysms with an interaneurysmal distance <10 mm. Posttreatment peak systole pressure was also increased significantly (P = 0.03). CONCLUSIONS: The hemodynamic changes in a distal aneurysm after treatment of a proximal aneurysm showed an unfavorable profile associated with an increased theoretical risk of bleeding.

Linear Accelerator Stereotactic Radiosurgery of Central Nervous System Arteriovenous Malformations: A 15-Year Analysis of Outcome-Related Factors in a Single Tertiary Center.

BACKGROUND: Linear accelerator stereotactic radiosurgery is one of the modalities available for the treatment of central nervous system arteriovenous malformations (AVMs). The aim of this study was to describe our 15-year experience with this technique in a single tertiary center and the analysis of outcome-related factors. METHODS: From 1998 to 2013, 195 patients were treated with linear accelerator-based radiosurgery; we conducted a retrospective study collecting patient- and AVM-related variables. Treatment outcomes were obliteration, posttreatment hemorrhage, symptomatic radiation-induced changes, and 3-year neurologic status. We also analyzed prognostic factors of each outcome and predictability analysis of 5 scales: Spetzler-Martin grade, Lawton-Young supplementary and Lawton combined scores, radiosurgery-based AVM score, Virginia Radiosurgery AVM Scale, and Heidelberg score. RESULTS: Overall obliteration rate was 81%. Nidus diameter and venous drainage were predictive of obliteration (P < 0.05), ruptured status and previous embolization were not related to rate of obliteration, and low-grade AVMs had higher obliteration rates. Posttreatment hemorrhage incidence was 8.72%; nidus diameter was the only predictor (P = 0.05). Symptomatic radiation-induced changes occurred in 11.79% of patients and were significantly associated with unruptured status (P < 0.05). Treatment success as a composite measure was obtained in 70.77% of patients. Receiver operating characteristic curves were presented for each scoring system and outcome measure; best area under the curve was 0.687 for Lawton combined score in the obliteration outcome. CONCLUSIONS: In the long-term, linear accelerator-based radiosurgery is a useful, valid, effective, and safe modality for treatment of brain AVMs.