1.3.1.5 General treatment considerations
Ruptured aneurysms are usually treated in the first 24 hours after the hemorrhage, except when there is an accompanying space-occupying bleeding in which immediate decompression is required. Both treatment options—clipping and coiling—are usually now available in neurovascular centers. While it is beyond the scope of this chapter, decision-making on how to treat the aneurysm is best done in an interdisciplinary discussion that should include several variables: clinical findings, comorbidities, medication, spasm, location, anatomy of the aneurysm neck, and calcification in the aneurysm wall.
In patients with asymptomatic aneurysms, the indication for treatment is not clear and cases need to be considered on an individual basis. There have been no validated studies on this topic. To provide counseling for patients, data are available from large case series and in particular from a quite controversial study, the International Study of Unruptured Intracranial Aneurysms (ISUIA). When the indication is being established, the following criteria need to be taken into account: patient’s age, comorbidities, medication, size and shape of the aneurysm, family history, and history of smoking. Space-occupying aneurysms and what are known as complicated aneurysms require particular individualized consideration. In addition to establishing the indication, the treatment technique—endovascular, surgical, or combined (e.g., with bypass)—also needs to be intensively discussed as well in these cases. New approaches to endovascular treatment have been developed recently (e.g., with flow diverters) and have allowed treatment of complicated aneurysms, which had previously been associated with unsatisfactory results. While treatment considerations include vascular reconstruction or occlusion of the aneurysmal vessel, the aim should be to consider how the space-occupying effect of these usually large and/or fusiform and sometimes thrombosed aneurysms can be relieved.
Conservative treatment
As the clinical findings are usually clear, patients with an SAB are admitted to hospital as emergency cases. These patients should be in an intensive-care ward or, if the clinical findings are less severe, a monitoring ward. In the initial phase of the disease, the patients are at risk of secondary bleeding and possible hydrocephalus. Independently of the treatment for the aneurysm with a clip or coil, conservative treatments should also be started: pain treatment, possible sedation, and prophylaxis against vasospasm are the cornerstones when ventilation is not required. Additional information on this topic follows in the section on intensive-care medicine below.
Endovascular treatment
Endovascular treatment for cranial artery aneurysms has become established since the introduction of Guglielmi detachable coils (GDCs) in the early 1990s as an alternative to neurosurgical clipping operations. The preferred indications for interventional or endovascular procedures are aneurysms in the posterior cranial fossa. All accompanying conditions (advanced age, comorbidities) that may make an open surgical procedure problematic, including a prolonged recovery, tend to favor an endovascular intervention. There are also sequelae of SAB, such as extensive vascular spasm and cerebral edema, which argue against brain surgery. Endovascular approaches are usually more appropriate for aneurysms with its neck located in the bony base of the skull, and aneurysms of the anterior communicating branch that are large (approximately 1 cm in diameter) and with the dome directed dorsally. By contrast, surgery is better for very large, broad-based aneurysms, sometimes including branch orifices in the aneurysmal neck. Many aneurysms can be treated equally well using either technique, particularly as they have both undergone considerable further development in recent years. The following advances and innovations should be mentioned here in connection with the endovascular technique:
Without an in-depth analysis of the International Subarachnoid Aneurysm Trial (ISAT), the following conclusions can be made: endovascular treatment has become established as an alternative and complementary form of treatment to surgery for cerebral artery aneurysms. A modern center for neurovascular treatment should have both capacities available. The prospective and randomized ISAT study showed a poor outcome (modified Rankin scale > 2) in approximately 24% of patients who received endovascular treatment, in comparison with 31% of those who underwent surgery for ruptured intracranial aneurysms. Generally speaking, the advantages of endovascular therapy lie in the fact that the intervention is less invasive, and this usually allows more rapid mobilization of the patient. The general disadvantage, particularly with large, broad-based aneurysms, is that recanalization is possible as a result of aggregation of the platinum coils and that it may not be possible to achieve complete occlusion of the aneurysm in this anatomic situation. It is not clear whether such recanalization is associated with a relevant risk of bleeding. In general, the rate of secondary bleeding from aneurysms after SAB is extremely low both after surgery and after coiling, as demonstrated in the ISAT study.
Fig. 1.3–4a-f Endovascular treatment of an aneurysm at the tip of the basilar artery. (a-f) DSA and road map images of the several steps involved in endovascular treatment of an aneurysm of the basilar artery tip. (a) AP projection before treatment. (b) Introduction of a catheter into the aneurysm. (c) During application of the first coil. (d, e) Imaging of the next treatment steps. (f) Final image after occlusion of the aneurysm with coils.
Endovascular treatment for an aneurysm (known as “coiling,” Fig. 1.3-4) can be described in outline as follows:
The typical complications of endovascular treatment consist of thrombus formation in the aneurysmal neck, with subsequent infarction, and perforation of the