Aneurysmal Subarachnoid Hemorrhage—Status Quo and Perspective

Abstract

Aneurysmal subarachnoid hemorrhage (SAH) accounts for about 5 % of all strokes and continues to be a major cause of morbidity and mortality, especially in younger patients (mean age of 52). The global incidence of SAH is 9 per 100, 000 per year with some regional variations [1]. Data from population-based studies suggests a distinct decrease in case fatality (0.9 % per year) over the past four decades to about 30 %, which is likely originated in earlier and more advanced aneurysm repair as well as improved neurocritical care of SAH patients following aneurysm repair [2]. Nevertheless, the incidence of poor functional outcome in SAH patients remains high (about one third of patients). The main determinants for poor outcome after SAH are the degree of early brain injury (EBI) and the incidence of delayed cerebral ischemia (DCI) (see below) [3, 4].The clinical course of SAH is complex and can be divided into an acute stage (the initial 72 h after SAH ictus) and a subacute stage, which lasts up until 20 days after SAH ictus. The potential main complications in the acute phase are EBI, rebleeding from the ruptured aneurysms, with a frequency of up to 23 % within the first 72 h, and acute hydrocephalus, occurring in about 20 % of the patients, whereas the main complications occurring in the subacute phase are DCI (formerly referred to as Bvasospasm,^see below), cardiopulmonary or other medical complications, as well as permanent hydrocephalus [5][6][7]. The term EBI refers not only to direct mechanical damage to the brain tissue due to the hemorrhage but also to a cascade of different pathomechanisms, incl. a temporary increase of intracranial pressure, consecutive reduction of cerebral blood flow and/or microcirculatory spasm, transient global ischemia, neuronal injury or apoptosis, and edema formation [8]. The degree of EBI is a strong and independent predictor for clinical outcome after SAH [9,3, 4]. The term DCI describes a complex phenomenon as a consequence of several pathomechanisms, incl. (1) macrovascular or angiographic vasospasm, i.e., narrowing of proximal cerebral arteries, (2) microvascular spasm, (3) microthromboembolism, (4) cortical spreading depolarization/ischemia, (5) autoregulatory dysfunction, and (6) inflammation [10-13, 7, 14-17]. The radiological term vasospasm has been widely replaced with the clinical term DCI, which describes a secondary neurological deterioration in the course SAH, excluding other causes of neurological deterioration; an explicit definition for DCI has been proposed by a multidisciplinary research group [16]. This Bparadigm shift^came along with the insight that angiographic vasospasm occurs in up to 70 % of SAH patients, whereas only 30 % of SAH patients develop clinical features of DCI and, moreover, because pharmaceutical treatments exclusively targeting of angiographic vasospasm failed to improve neurological outcome after SAH [18][19][20]. However, in those clinical studies where cerebral infarction due to DCI was effectively reduced by experimental pharmaceutical tre...

MRI Characterization in the Acute Phase of Experimental Subarachnoid Hemorrhage

“…Subarachnoid hemorrhage (SAH) is a devastating disease resulting in high mortality, especially within the first few days after aneurysm rupture(1, 2). However, the mechanism of brain injury during the acute period remains poorly understood and therapeutic options are limited(3, 4).…”

DLK silencing attenuated neuron apoptosis through JIP3/MA2K7/JNK pathway in early brain injury after SAH in rats

“…Subarachnoid hemorrhage (SAH) is a severe and devastating cerebrovascular disease with high mortality and disability rates (Etminan, 2015; Grunwald et al, 2014). After SAH, early brain injury (EBI) and delayed cerebral vasospasm contribute to the poor clinical outcome (Chen et al, 2013a; Hasegawa et al, 2015).…”

Hydrogen Inhalation Attenuates Oxidative Stress Related Endothelial Cells Injury After Subarachnoid Hemorrhage in Rats

“…Subarachnoid hemorrhage (SAH) is a life threatening cerebrovascular disease with high morbidity and mortality. SAH mainly affects middle-aged patients and accounts for the highest fatality among all stroke subtypes, which places a huge burden on the economy and society (Suarez et al, 2006;Etminan, 2015). Early brain injury (EBI), a series of pathophysiological changes occurring within the first 72 h after SAH, has been considered a major cause of death and poor outcomes following SAH (Cahill et al, 2006;Caner et al, 2012;Sehba et al, 2012).…”