Description of the effect of ACA-A1 segment hypoplasia on aneurysm formation in acom aneurysms with dsa

Anterior communican artery aneurysms (AComAAs) are the most common type of aneurysm in neurosurgery clinics. AComAAs, which are thought to constitute approximately 30-35% of all intracranial aneurysms, have a rate of approximately 90% among anterior circulation aneurysms. The structural weakness of the anterior circulation and the predisposition of its morphology to aneurysm formation are thought to be the main reasons for this. Depending on the difference in diameter between the proximal anterior cerebral arterys (ACA), blood flow and blood pressure in the anterior communican artery (AComA) change. Flow and pressure are greater on the wider A1 segment side, so the junction of the wider A1 segment and the AComA becomes more prone to aneurysm formation. In this study, it was planned to research the contribution of ACA- A1 segment hypoplasia to aneurysm formation in patients with AComAA. It was aimed to show the effect of ACA- A1 segment hypoplasia on aneurysm formation. In this study, the results of digital subtraction angiography (DSA) performed in the neuroangiography unit of our hospital's neurosurgery service and intensive care unit between January 2016 and December 2020 were analyzed retrospectively. While patients with AComAA were evaluated as the first group, patients with other arterial aneurysms in the anterior circulation (ACA, internal carotid artery, middle cerebral artery) and DSA negative subarachnoid hemorrhage (SAH) were evaluated as the second and third group, and in these patients the diameters of the segment (ACA- A1 segment) were measured too. Whether the quantitative variables were suitable for normal distribution was examined with the Kolmogorov-Smirnov test. The relationship between qualitative variables was investigated by chi-square analysis. Descriptive statistics of quantitative variables were presented as mean±standard deviation or minimum-maximum. Descriptive statistics for qualitative variables were expressed as frequency (%). p<0.05 values were considered statistically significant. In order to obtain data, a total of 584 patients were studied. In addition to general evaluations such as age and gender, aneurysm location, ACA-A1 segment diameter, filling direction of the aneurysm, A1 segment hypoplasia or aplasia, if any, were evaluated. As a result of our study, the incidence of ACA-A1 segment hypoplasia in patients with AComAA was observed to be significantly higher than the general average. No significant difference was observed between A1 variations in other arterial aneurysms or in patients without aneurysm. As a result of the data obtained in this study, it can be predicted that A1 segment hypoplasia may affect blood flow and hemodynamic stress, and as a result, it will pave the way for aneurysm formation. The rates we found in patients with AComAA supported the hypothesis predicted in our study. Key words: A1 segment, Aneurysm, Hypoplasia,