Objective To summarize and discuss the clinical characteristics of ruptured vertebral artery coarctation aneurysms and emergency interventional treatment techniques. Methods The clinical manifestations, imaging characteristics and interventional treatment of 20 cases of ruptured vertebral artery coarctation aneurysms were reviewed and analyzed. The main clinical manifestation of the 20 cases of ruptured vertebral artery entrapment aneurysm was spontaneous subarachnoid hemorrhage (or combined hydrocephalus), and 13 cases (61.9%) showed the string of beads sign on DSA imaging; 18 of the 20 cases with well-developed contralateral vertebral artery were treated by embolization of the entrapment aneurysm combined with occlusion of the aneurysm-carrying artery, and the survival rate was 94.4% (17/18). No recurrence of the occluded vessel or aneurysm was observed at follow-up. It is concluded that emergency aneurysm embolization combined with aneurysm-carrying artery occlusion is a safe and effective approach for ruptured vertebral artery coarctation aneurysms. In recent years, with the maturation of endovascular treatment, more and more vertebral artery dissecting aneurysms (VADA) have been effectively treated by interventional means. However, there is a lack of uniform treatment standards, and the choice of interventional approach is still controversial, especially for vertebral artery dissecting aneurysms involving important branches. We treated 20 cases of hemorrhagic VADA from January 2008 to December 2010, among which 18 cases with well-developed vertebral arteries achieved good results by embolization of the entrapped aneurysm combined with occlusion of the aneurysm-carrying artery, which are reported below. Data and methods 1. General data: 12 men and 8 women, age 35-64 years, average 54.3 years. Condition at admission: Hunt-Hess classification: grade 1 in 2 cases, grade 2 in 6 cases, grade 3 in 6 cases, grade 4 in 4 cases, and grade 5 in 2 cases; all had subarachnoid hemorrhage of different degrees as the first symptom, 11 cases had spider blood returning into the third and fourth ventricles and lateral ventricles, and 4 of them combined with acute obstructive hydrocephalus. There were three cases with unstable respiratory and cardiac vital signs and tracheal intubation before surgery. 2. Imaging data: In this group of cases, 16 cases underwent CT angiography (CTA) before DSA to clarify the diagnosis, and the other 4 cases (those with H-H grade 4-5 and unstable vital signs) underwent direct angiography. The diagnosis of all vertebral artery coarctation aneurysms was confirmed by DSA, and 13 cases (61.9%) showed eccentric aneurysmal dilatation with proximal (or distal) stenosis, i.e., the string of beads sign (or “bead line sign”), 5 cases (28.6%) showed shuttle artery dilatation, and 2 cases (9.5%) showed double lumen sign. In all patients, DSA angiography showed the course, thickness, and communication anastomosis of the vertebral artery (VA), posterior inferior cerebellar artery (PICA), anterior inferior cerebellar artery (AICA), and superior cerebellar artery (SCA) on the side of the lesion, as well as the development of the VA and posterior communicating artery on the opposite side and the relationship between the union of the vertebrobasilar artery and the lesion. According to the relationship with the location of PICA, the intercalated aneurysms were divided into three categories: 8 cases with lesions located near the PICA, 10 cases with lesions located far from the PICA, and 2 cases with lesions involving or encircling the beginning of the PICA. All patients underwent angiography and embolization of the entrapped aneurysm combined with occlusion of the aneurysm-carrying artery within 24 hours of the onset of the disease. 2 of the 4 patients with acute obstructive hydrocephalus underwent extraventricular drainage before the intervention, and the other 2 underwent extraventricular drainage immediately after the intervention. 3 other patients with postoperative complications of hydrocephalus underwent ventriculoatrial or ventriculoperitoneal shunts. The interventions were performed under general anesthesia, and the femoral arteries were punctured bilaterally using the Seldinger technique and a vascular sheath was placed. A guide catheter was placed in the vertebral artery on the side of the lesion, and the location of the lesion in relation to the PICA was clarified by imaging, and the vertebral artery on that side was temporarily blocked with a Hyperform balloon (EV3), focusing on the filling of the PICA on that side (Figures 1 and 3); in addition, a vertebral arteriogram of the healthy side was required, and if the contralateral vertebral artery was significantly thinner than the diseased side or even terminated in the posterior inferior cerebellar artery, a temporary balloon was not considered In addition, if the contralateral vertebral artery is significantly smaller than the diseased side or even terminates in the posterior inferior cerebellar artery, temporary balloon occlusion of the diseased vertebral artery and sacrifice of the vertebral artery are not considered. If the PICA and posterior circulation filled well after occlusion of the vertebral artery (in 18 cases in this group), the decision was made to perform VADA embolization and vertebral artery occlusion on the diseased side. The balloon was withdrawn, the microcatheter was inserted into the lumen of the VADA aneurysm using a microguide, and the microcatheter was withdrawn into the vertebral artery proximal to the aneurysm after the aneurysm lumen was loosely filled with a spring coil, and local spring coil occlusion of the vertebral artery proximal to the lesion was performed, with the occlusion being as short and dense as possible until the vertebral artery was completely occluded. During embolization, care should be taken to avoid the spring coil from affecting the PICA, the basilar artery, the anterior spinal artery and other important vessels. Results All 18 cases of occlusion of aneurysms and occlusion of aneurysm-carrying vertebral arteries were successful, with no intraoperative aneurysm rupture and no postoperative rebleeding. Except for one patient who died from a serious postoperative pulmonary infection, all patients survived, with a survival rate of 94.4% (17/18). The remaining 15 patients were followed up through inpatient review, outpatient review, and telephone, and the follow-up period was from 3 months to 12 months. The GOS score was 1 (death), 2 (vegetative survival), 3 (severe disability), 3 (mild disability), and 5 (good recovery) in 11 patients. 3 months and 1 year postoperative DSA review did not show any occluded artery or aneurysm recanalization or stenosis in any of the 15 patients. Discussion The annual incidence of intracranial vertebral artery coarctation aneurysm is about 1-1.5/100,000 people, and the average age of onset is about 50.29-55.2 years [1], and most of them have hemorrhage as the first symptom [2], and the mortality rate of rebleeding is high, and it is easy to combine with hydrocephalus or brainstem failure to cause rapid deterioration of the disease, so they need emergency management. DSA is still the main diagnostic imaging standard for this disease; meanwhile, CT angiography (CTA) and MRI techniques (including MRA) can provide abundant information for diagnosis and treatment with increasing sensitivity and specificity [3]. Therefore, we perform preoperative emergency CTA examination as much as possible to provide some reference for the initial screening of the disease and the choice of treatment direction. The typical imaging features of vertebral artery entrapment aneurysm include: string bead sign, double lumen sign, intermural hematoma, and spindle-shaped arterial dilatation. It occurs due to various causes of tearing of the endothelium of the arterial vessel to form an inflow tract, and blood flow continuously enters the rupture to form a vessel wall sandwich. If the lesion spreads along the interstitial and epicentral membranes, it forms an eccentric or spindle-shaped dilated pseudoaneurysm outward, while spreading along the interstitial and epicentral membranes causes ischemic manifestations such as stenosis by inward compression [4]. In 60% (12/20) of our cases, DSA angiography of vertebral artery entrapment aneurysms showed the aforementioned shuttle-shaped dilatation or eccentric dilatation with distal and proximal stenosis, but the double-lumen sign was less common (Figure 2). Currently, aggressive surgical treatment of ruptured VADA is advocated to reduce rebleeding and mortality [2]. The endovascular techniques include the so-called “deconstructive technique” and “reconstructive technique” [5]. The former is aimed at reducing the risk of rebleeding by occluding the aneurysm-carrying artery with a balloon or spring-ring occlusion to block the flow of blood through the entrapment [6], but there is still a risk of rebleeding by simply embolizing the aneurysm-carrying artery [7]. Reconstruction techniques are used to treat the diseased portion of the aneurysm on the basis of preserving or reconstructing the aneurysm-carrying artery using stenting techniques, including stent-assisted aneurysm occlusion, simple stenting techniques, and overlapping stenting techniques [4,8,9]; although stenting techniques for VADA have been reported more frequently in recent years, they cannot completely avoid the risk of intraoperative and postoperative aneurysm re-rupture and bleeding [10], and the emergency management of ruptured bleeding VADA should also take into account the use of stenting techniques. For example, in our group, there were 4 cases of acute combined obstructive hydrocephalus and 3 cases of postoperative traffic hydrocephalus that underwent extraventricular drainage or shunt surgery, and the use of antiplatelet drugs after stenting will definitely increase the risk of bleeding in surgical management. Therefore, we believe that occlusion of the aneurysm-carrying artery along with embolization of the ruptured entrapped aneurysm is one of the most reliable ways to prevent rebleeding in VADA [13]. Since vertebral artery entrapment is mostly a paralleling tear of the vessel wall in the direction of blood flow, this treatment not only avoids the direct impact of paralleling blood flow on the weak aneurysm wall, but also reduces the continued impact and tearing of the inflow tract of the entrapment on the carrier artery, minimizing the risk of postoperative recurrence or rebleeding of the entrapment and the possibility of distant healing of the entrapment, and a total of 15 cases in our group who received imaging follow-up did not see any All 15 cases with imaging follow-up in this group did not show any significant recurrence within 1 year after surgery and were still in the process of long-term follow-up. The following aspects should be noted when performing embolization of a coarctation aneurysm combined with occlusion of the aneurysm-carrying aneurysm: First, because of the rapid onset and progression of ruptured VADA, it is difficult to perform preoperative balloon occlusion experiments, so it mostly relies on intraoperative imaging and temporary balloon block of the vertebral artery for adequate evaluation, which should pay special attention to [14]: (1) the development of the healthy vertebral artery and the posterior communicating artery: if the balloon occludes the lesion (ii) whether the PICA on the side of the lesion is involved and the relationship with the location of the coarctation aneurysm (2) whether the PICA on the side of the lesion is involved and its location in relation to the clogged aneurysm: these include three cases in which the clogged aneurysm is located proximal to the PICA, distal to the PICA, or involves the PICA; (3) the thickness of the AICA and SCA on the side of the lesion and whether there is communication with the earthworm branch of the PICA to determine the severity of postoperative ischemia that occurs once the PICA is affected. Secondly, in the case of a fully developed vertebral artery on the healthy side, if the VADA does not involve the PICA, then embolization of the aneurysm and occlusion of the vertebral artery on the side of the aneurysm should be considered; if the VADA is located near the PICA, then the PICA should be supplied by the contralateral vertebral artery after occlusion of the vertebral artery (Figure 1), and if it is located far from the PICA, then the proximal vertebral artery should be supplied. It should be noted that the intra-arterial spring-ring filling need not be too dense, but only need to be loosely filled to prevent the rupture of the interstitial part due to the increasing tear of the spring-ring filling, while the vertebral artery proximal to the lumen needs to be densely filled to prevent the impact of the cascade on the interstitial layer, and in this process, we usually use an intravascular occlusion with an expanding ring or a long soft ring to better confine the spring-ring to a shorter distance of the lumen, which not only fills more densely, but also allows postoperative occlusion of important branch vessels such as the anterior spinal artery. The occlusion of important branch vessels such as the anterior spinal artery may also be greatly reduced after surgery. If the aneurysm involves the beginning of the PICA, we usually embolize the VA proximal to the aneurysm in order to block the flow impact in the interstitial layer, and in some cases, the lumen of the aneurysm can be partially occluded by protecting the beginning of the PICA with a balloon to ensure the opening of the PICA. In some cases, partial intracavitary occlusion of the aneurysm lumen can be performed by balloon protection of the beginning of the PICA to ensure patency of the PICA opening and compensate for the blood supply via the contralateral VA regurgitation, which ultimately reduces the possibility of re-rupture and bleeding of the interstitial layer and provides a certain possibility of self-healing, as confirmed by follow-up observations [15]. Although very few reports suggest that occlusion of PICA may be tolerated more than usually expected, most scholars believe that occlusion of PICA may result in severe postoperative ischemic complications in about 2/3 of cases, and therefore sacrifice of PICA should be avoided even in emergencies for this rare condition [16].