The comparison of perioperative pressure measurements in intra-aneurysmal and parent artery in ruptured and unruptured aneuryms

ABSTRACT: PURPOSE: This study conducted pressure measurements in the aneurysm vesicle and the parent artery during the endovascular treatment aneurysms and investigated whether these measurements showed differences between intra-aneurysmal and intra-parent artery; also investigated whether the degree of this difference, if present, was similar in ruptured and unruptured aneurysms and the effect of this on the rupture. In addition, the three-dimensional cerebral angiograms of the aneurysms were obtained. In these images, the aneurysm morphological measurements such as aneurysm height, longest dimension from neck to dome tip (height: H), aneurysm width, maximal dome dimension (Dmax), aneurysm neck width were conducted and the average volume of the aneurysm was calculated. Apart from these, the relation between the aneurysm and the parent artery was evaluated and the inflow angles were measured. AR was computed by dividing height by neck width and H/W by aneurysm width.The inflow angle was measured as the angle between axis of flow in the parent vessel at the level of the aneurysm neck and the aneurysm?s main axis from the center of the neck to the tip of the dome. MATERIALS AND METHODS: The patients who had been treated in the Interventional Neuroradiology unit at Dokuz Eylül University Radiology Department between May and December 2012 were included in this study. The age, sex, blood pressure and smoking habit information of the patients were recorded. All ruptured and unruptured aneurysm patients within this period were included in the study. In all cases the artery containing the aneurysm was imaged using the artery catheter angiography (digital subtraction angiography). For this purpose, the aneurysm was catheterized with a micro-catheter and filled with micro-coils. The measurements were performed during the necessary micro-catheterization process. The measurements were performed just before the micro-catheter was pushed into the aneurysm vesicle and just after it was pushed. When the tip of the micro-catheter reached the point of measurement, the outer end of the micro-catheter was connected to the pressure measurement line and the measurement was performed. For correct measurement, it was made sure that the arterial pressure trace was seen on the pressure monitor and systolic, diastolic and average pressures were recorded. Simultaneously, the radial artery blood pressure measurements, which had been used for monitoring the arterial blood pressure in all interventions, were recorded. Three-dimensional cerebral angiograms were obtained from AlluraXPer FD20 Biplane (Philips, Nedherlands) systems and reconstructed using their respective clinical software packages.In these three-dimensional images aneurysm height, aneurysm width, maximal dome dimension, aneurysm neck width and the inflow angle were measured. Volumetric data sets, including aneurysm and parent vessel, were analyzed. RESULTS: 40% of the aneurysms participated in the study received endovascular treatment. 17 (42.5%) of these aneurysms were non-bleeding, and 23 (57.5%) of them were bleeding aneurysms. The average age in the bleeding aneurysm group was found 50.8 (±11,7), while it was found 53,2 (±13,8). The males in the bleeding aneurysm group were 12 (52.2%), and 10 (71.4%) in the non-bleeding aneurysm group. The females in the bleeding aneurysm group were 11 (47.8%) and 4 (28.6%) in the non-bleeding aneurysm group. Smoking habit was found in 16 individuals (69.6%) in the bleeding aneurysm group, while it was found in 8 individuals (57.1%) in the non-bleeding group. Hypertension was found in 7 patients (30.4%) in the bleeding aneurysm group; it was found in 4 patients (28.6%) in the non-bleeding aneurysm group. Family history of aneurysm was found in 2 people (8.7%) in the bleeding aneurysm group, while it was also found in 2 people (14.3%) in the non-bleeding aneurysm group. When the groups with bleeding and non-bleeding aneurysm were compared, any statistically significant difference could not be found between these two groups with regard to the demographic data of and the risk factors for the patients (p>0,05). The patients showed a homogenous distribution in both groups. When the ruptured and unruptured aneurysm groups were compared, any statistically significant difference between the peroperative pressure measurements in the aneurysm vesicle and the parent artery was not found (p>0,05). When the peroperative period data were evaluated any statistically significant difference was not found between the pressures in the parent artery and the aneurysm vesicle (p>0,05) with reference to bleeding and non-bleeding aneurysm groups. With regard to the aneurysm morphological measurement data, any statistically significant difference was not found between ruptured and unruptured aneurysm groups (p>0,05). CONCLUSION: Intracranial aneurysms comprise a group of diseases with high morbidity and mortality when they are ruptured. The mechanisms that accompany the formation, development and rupture of these aneurysmsare not wholly discovered yet. As the reasons that trigger the formation of an aneurysm develop the aneurysm continues to get larger. It is thought that the flow in the aneurysm is affected by the geometry of the dilatation of the parent artery, the relation between the aneurysm and the parent artery, the aneurysm volume and the aspect ratio. In this study, measurements were performed for the pressure in the aneurysm vesicle and the parent artery for bleeding and non-bleeding aneurysms during the aneurysm micro-catheterization in the endovascular treatment of aneurysms; it was investigated whether these measurements showed difference in the vesicle and in the parent artery, and if present whether this difference was the same for bleeding and non-bleeding aneurysms; and its effects on the rupture. The measurements in the parent artery and in the aneurysm showed that intra-aneurysm pressures are parallel to the intra-artery pressures (6). This finding sheds light on the significance of hypertension in aneurysm rupture. The peroperative pressure measurements in the aneurysm vesicle and the parent were foundsimilar in both bleeding and non-bleeding aneurysms, and any statistical difference in any finding was not found between the groups. This conclusion may help defining the hemodynamic variable which is most related to clinical progression and rupture, explaining the effects pertaining to these mechanisms, and developing treatment approaches. These measurements are considered to contribute to the studies to be conducted to understand the aneurysm rupture risks. With the results of this study, and others alike, we believe that the mechanisms that play a role in the formation, growth and the rupture of intracranial aneurysms will be revealed, and a contribution will be made the knowledge towards better understanding of these rupture mechanisms.