**4.8 Antifibrinolytics**

When early definitive treatment of the ruptured aneurysm is not possible, antifibrinolytic therapies such as amino epsilon caproic acid or tranexamic acid can be considered to reduce the risk of early aneurysmal rebleeding. Early studies showed a reduction in rebleeding but an increase in cerebral ischemia with prolonged use of antifibrinolytics [88]. Neither aminocaproic acid or tranexamic acid is approved by the US Food and Drug Administration for prevention of aneurysmal rebleeding, thus the use of antifibrinolytic therapies should be discussed on a case-by-case basis.

## **4.9 Rebleeding**

Rebleeding can occur before the ruptured aneurysm is secured, and is associated with significant mortality and poor prognosis for functional recovery, most common within the first 24 hours, with some studies reporting peak time of rebleeding within 2 hours [88]. Factors associated with rebleeding include longer time to aneurysm treatment, worse neurologic status on presentation, initial loss of consciousness, previous sentinel headaches, larger aneurysm size, and possibly SBP greater than 160 mm Hg [91]. Although early definitive treatment of ruptured aneurysms can reduce the risk of rebleeding, approximately 12–15% of patients die before reaching the hospital [90].

#### **4.10 External ventricular drainage**

Acute hydrocephalus is common in patients with SAH and is a common cause of early neurologic decline. Treatment of symptomatic hydrocephalus often requires placement of an external ventricular drain, which allows ICP monitoring as well as CSF drainage. Untreated hydrocephalus can lead to intracranial hypertension and cerebral ischemia with potential cerebral herniation. Identification of the presence of hydrocephalus on CT and communication of this finding with neurosurgical consultants are key steps in the management of SAH.

#### **4.11 Microsurgical clipping versus endovascular coiling**

Definitive treatment of SAH is early microsurgical clipping or endovascular coiling of the ruptured aneurysm to prevent rebleeding and its associated complications. Choice of treatment modality depends on aneurysm size, characteristics, and location, as well as the patient's clinical grade and comorbidities [92]. The International Subarachnoid Aneurysm Trial (ISAT) [93] is a multicenter, randomized clinical trial, which compares a policy of neurosurgical clipping with a policy of endovascular treatment with detachable platinum coils in patients with ruptured intracranial aneurysms considered suitable for either treatment. The results show that endovascular intervention with detachable platinum coils in patients with ruptured intracranial aneurysms can improve the chances of independent survival compared with neurosurgical intervention to clip the neck of the aneurysm.

#### **4.12 Pipeline embolization device**

The PED has mostly been used to treat unruptured aneurysms, whereas its use for acutely ruptured aneurysms has been limited and is theoretically contraindicated, given the need for dual antiplatelet therapy as it increases the risk of re-hemorrhage [94].

**195**

*Endovascular Treatment of Brain Aneurysms DOI: http://dx.doi.org/10.5772/intechopen.88964*

**5. Future directions**

**5.1 Flow disruptor**

**5.2 Flow diverter**

treated in the near future.

**5.3 Endosaccular coiling**

designs for smaller ruptured aneurysms [98].

However, in certain cases of complex ruptured aneurysms, the PED may still serve as a good alternative (and sometimes may be the only available option) because these aneurysms are anatomically and technically more difficult to treat using standard techniques [93]. Furthermore, certain anticoagulation protocols can be put into place to prevent the feared consequences associated with PED placement in ruptured aneurysms due to dual antiplatelet therapy. The standard management for the prevention of thromboembolic events when using flow diverters is pretreatment with aspirin and clopidogrel for 7–10 days prior to the procedure. When treating ruptured aneurysms with the PED in conjunction with this dual antiplatelet therapy, there is a concern for hemorrhagic complications. Chalouhi and colleagues [95] described a new regimen for anticoagulation that was recently implemented in the hope of minimizing the risk of thromboembolic and hemorrhagic complications. In summary, the PED may be particularly helpful in acutely ruptured aneurysms that are not amenable to coiling or clipping. It can also be used in a staged fashion 1 or 2 weeks after partial coiling of the aneurysm dome. It is generally preferable to place an external ventricular drain if treatment with the PED is contemplated [96].

The future of neuroendovascular surgery is bright. The technology platforms for access, delivery and treatment continue to improve at exponential rates. As it is there has been a rapid change in the number of brain aneurysm patients treated with endovascular treatment versus open surgical clipping. With this change comes a great void in experience and skill in the open surgical management of brain aneurysms. It remains to be seen whether this skill will be needed in the future [97].

Currently there is only one flow disruptor available in the US market; the WEB device. Currently, its limitations lie in the fact that it is only available in sizes to treat aneurysms 3–10 mm in size. The second limitation exists in its delivery system which, at larger sizes requires a 33-microcatheter, and at smallest sizes requires a 21-microcatheter. As newer generations come to market over the next 5 years, we expect there to be improved deliverability, different shapes available, and smaller

Currently there are two flow diverter stents available in the US Market, the Pipeline Flex (2nd generation), and the Surpass. Currently the bulk of innovation required with this technology is in finding a coating for the stent that might mitigate the need for dual anti-platelet therapy. The second area of innovation is in the deliverability of the stents, currently needing 27-microcatheter for delivery, there is an expectation that these stents can be delivered through a 21-microcatheter in the near future, with also smaller diameter stent sizes available to treat more distal aneurysms. We fully expect the indications on which type of aneurysms can be

Coiling has likely reached its technological pinnacle. There has been little advancement in this technology over the last 5 years. One area of interest is in *Endovascular Treatment of Brain Aneurysms DOI: http://dx.doi.org/10.5772/intechopen.88964*

*New Insight into Cerebrovascular Diseases - An Updated Comprehensive Review*

When early definitive treatment of the ruptured aneurysm is not possible, antifibrinolytic therapies such as amino epsilon caproic acid or tranexamic acid can be considered to reduce the risk of early aneurysmal rebleeding. Early studies showed a reduction in rebleeding but an increase in cerebral ischemia with prolonged use of antifibrinolytics [88]. Neither aminocaproic acid or tranexamic acid is approved by the US Food and Drug Administration for prevention of aneurysmal rebleeding, thus the use of antifibrinolytic therapies should be discussed on a case-by-case

Rebleeding can occur before the ruptured aneurysm is secured, and is associated with significant mortality and poor prognosis for functional recovery, most common within the first 24 hours, with some studies reporting peak time of rebleeding within 2 hours [88]. Factors associated with rebleeding include longer time to aneurysm treatment, worse neurologic status on presentation, initial loss of consciousness, previous sentinel headaches, larger aneurysm size, and possibly SBP greater than 160 mm Hg [91]. Although early definitive treatment of ruptured aneurysms can reduce the risk of rebleeding, approximately 12–15% of patients die

Acute hydrocephalus is common in patients with SAH and is a common cause of early neurologic decline. Treatment of symptomatic hydrocephalus often requires placement of an external ventricular drain, which allows ICP monitoring as well as CSF drainage. Untreated hydrocephalus can lead to intracranial hypertension and cerebral ischemia with potential cerebral herniation. Identification of the presence of hydrocephalus on CT and communication of this finding with neurosurgical

Definitive treatment of SAH is early microsurgical clipping or endovascular coiling of the ruptured aneurysm to prevent rebleeding and its associated complications. Choice of treatment modality depends on aneurysm size, characteristics, and location, as well as the patient's clinical grade and comorbidities [92]. The International Subarachnoid Aneurysm Trial (ISAT) [93] is a multicenter, randomized clinical trial, which compares a policy of neurosurgical clipping with a policy of endovascular treatment with detachable platinum coils in patients with ruptured intracranial aneurysms considered suitable for either treatment. The results show that endovascular intervention with detachable platinum coils in patients with ruptured intracranial aneurysms can improve the chances of independent survival compared with neurosurgical intervention to clip the neck of the aneurysm.

The PED has mostly been used to treat unruptured aneurysms, whereas its use for acutely ruptured aneurysms has been limited and is theoretically contraindicated, given the need for dual antiplatelet therapy as it increases the risk of

**4.8 Antifibrinolytics**

basis.

**4.9 Rebleeding**

before reaching the hospital [90].

**4.10 External ventricular drainage**

**4.12 Pipeline embolization device**

consultants are key steps in the management of SAH.

**4.11 Microsurgical clipping versus endovascular coiling**

**194**

re-hemorrhage [94].

However, in certain cases of complex ruptured aneurysms, the PED may still serve as a good alternative (and sometimes may be the only available option) because these aneurysms are anatomically and technically more difficult to treat using standard techniques [93]. Furthermore, certain anticoagulation protocols can be put into place to prevent the feared consequences associated with PED placement in ruptured aneurysms due to dual antiplatelet therapy. The standard management for the prevention of thromboembolic events when using flow diverters is pretreatment with aspirin and clopidogrel for 7–10 days prior to the procedure. When treating ruptured aneurysms with the PED in conjunction with this dual antiplatelet therapy, there is a concern for hemorrhagic complications. Chalouhi and colleagues [95] described a new regimen for anticoagulation that was recently implemented in the hope of minimizing the risk of thromboembolic and hemorrhagic complications. In summary, the PED may be particularly helpful in acutely ruptured aneurysms that are not amenable to coiling or clipping. It can also be used in a staged fashion 1 or 2 weeks after partial coiling of the aneurysm dome. It is generally preferable to place an external ventricular drain if treatment with the PED is contemplated [96].
