Which of the following clinical signs is most suggestive of a ruptured aneurysm?

Endovascular techniques for treating aneurysms date back to the 1970s with the introduction of proximal balloon occlusion by Fjodor A. Serbinenko, MD, a Russian neurosurgeon. During the 1980s, endovascular treatment of aneurysms with balloon occlusions was associated with high procedural rate of rupture and complications. Guido Guglielmi, MD, an American-based neuroradiologist, invented the platinum detachable microcoil, which was used to treat the first human being in 1991. The development of Guglielmi detachable coils (GDCs), and their FDA approval in 1995, revolutionized endovascular treatment of cerebral aneurysms.

How is an Aneurysm Endovascularly Coiled?

The common goal of both surgical clipping and endovascular coiling is to eliminate blood flow into the aneurysm. Efficacy (long-term success or effectiveness of the treatment) is measured by evidence of aneurysm obliteration (failure to be demonstrated by conventional or noninvasive angiography), without evidence of recanalization (any blood flow into the aneurysm) or recurrence (reappearance).

Guglielmi detachable coils, known as GDCs, are soft wire spirals originally made out of platinum. These coils are deployed (released) into an aneurysm via a microcatheter that is inserted through the femoral artery of the leg and carefully advanced into the brain. The microcatheter is selectively advanced into the aneurysm itself, and the microcoils are released in a sequential manner. Once the coils are released into the aneurysm, the blood flow pattern within the aneurysm is altered, and the slow or sluggish remaining blood flow leads to a thrombosis (clot) of the aneurysm. A thrombosed aneurysm resists the entry of liquid blood, providing a seal in a manner similar to a clip.

Endovascular coiling is an attractive option for treating aneurysms because it does not require opening of the skull, and is generally accomplished in a shorter time frame, which lessens the anesthesia given. Nevertheless, important differences remain between clipping and coiling, including the nature of the seal created. Because coiling does not physically re-approximate the inner blood vessel lining (endothelium), recanalization may occur through the eventual compaction of the coils into the aneurysm by the bloodstream.

One of the largest, randomized controlled trials comparing surgical clipping and endovascular coiling — International Subarachnoid Aneurysm Trial (ISAT) — randomly allocated the patients to either neurosurgical clipping or endovascular coiling after a SAH. In the first report published in 2002, 2,143 participants were enrolled and randomly assigned to the endovascular coiling group and the surgical clipping group. They concluded that survival (free of disability) at one year was better with endovascular coiling. Long-term risk of further bleeding from treated aneurysm was low with either therapy, but higher with endovascular coiling, as compared to surgical clipping (5).

The investigators recently published the long-term outcomes from 1,644 patients enrolled from 22 U.K. neurosurgical centers who were followed up for 10–18.5 years for death and clinical outcomes. At long-term follow-up rates of increased dependency alone did not differ between groups, the probability of death or dependency was significantly greater in the neurosurgical group and re-bleeding was more likely after endovascular coiling (6).

However, this study, like many other stroke trials, has many shortcomings and should be interpreted with caution (7). Meta-analyses of randomized trials comparing endovascular coiling and surgical clipping (including ISAT) conducted later were unable to show a significant difference between endovascular treatment and neurosurgical clipping in mortality and reported that endovascular treatment was associated with higher rates of re-bleeding (8, 9).

Often endovascular coiling may need to be performed with stent — or balloon assistance — for complex aneurysms such as wide-necked aneurysms with lower dome-to-neck ratios, large and giant aneurysms. Stent — or balloon-assisted coiling — is done to prevent herniation of the coil mass into the parent artery which can result in stroke. For balloon-assisted coiling, the balloon is temporarily inflated at the neck of the aneurysm while the coils are placed into the aneurysm. For stent-assisted coiling, the stent is permanently placed across the aneurysm neck. There are advantages and disadvantages of both approaches.

The patients who have the stent placed need to be on anti-platelets medications, limiting their use in ruptured aneurysms, although stent-assisted coiling has been used in ruptured aneurysms with good outcomes. Stents have also been shown to reduce aneurysm recanalization and result in further occlusion of incompletely coiled aneurysms (10, 11). A literature review on stent-assisted coiling in 2012 reported the overall complication rate of 19 percent with an overall death rate of 2.1 percent (12).

Flow diverter (FD) stents were introduced about 7 years ago into the clinical armamentarium of the neuro-interventionists as an additional tool for aneurysm treatment. They have higher metal surface area coverage (about 30-35 percent) as compared to the previous generation stents which have about 8-10 percent metal surface-area coverage (13).

FDs are tubular stent-like implants with a low porosity (metal-free to metal-covered area) and a high pore density with two main work mechanisms (14):

• Flow diversion: As the name indicates, FDs bridge the aneurysm neck and divert the blood flow away from the aneurysm sac, due to impedance created by the mesh of the implant. Reduction of the blood flow into the aneurysmal sac causes stasis of blood flow within the aneurysm which then leads to an inflammatory response followed by thrombosis and “healing” of the aneurysm.
• Endoluminal reconstruction of the parent artery: The FD provides a scaffold for neo-endothelialization across the aneurysm neck and results in endoluminal reconstruction of the parent artery excluding the aneurysm from the circulation.

FD stents clinically available at the current time include:

• Pipeline Embolization Device (EV3-MTI, Irvine, CA)
• Silk (Balt, Montmorency, France)
• Surpass (Stryker, Fremont, CA)
• and Flow Redirection Endoluminal Device (FRED) (Microvention, Tustin, CA)

Pipeline embolization device (PED) is currently used most often in the U.S. and most of the literature on flow-diversion for intracranial aneurysms is based on its use. The PED is a flexible microcatheter-delivered self-expanding cylindric construct composed of 48 braided strands of cobalt chromium and platinum. The Food and Drug Administration (FDA) approved the PED for the treatment of large or giant wide-necked intracranial aneurysms from the petrous to the superior hypophyseal segments of the internal carotid artery (ICA), which is a section of the artery that supplies the blood to the brain. (15) Over the last few years, PED has also been used beyond the FDA approved indications as an “off-label device” with good outcomes. (16)

The concept behind the treatment is the same with all four FDs. Flow diversion is generally performed for the treatment of aneurysms that are challenging and less amenable to traditional endovascular coiling; such as complex aneurysms, including large and giant aneurysms, wide-neck aneurysms, fusiform aneurysms and recanalized aneurysms after previous coiling. Stent-assisted coiling and balloon-assisted coiling are alternative endovascular options for such aneurysms; however, some studies reported their limited efficacy due to high recanalization rates (12).

Dual antiplatelet therapy with Plavix (Clopidogrel) and aspirin (ASA) is recommended starting prior to the placement of the device and continued afterwards for three to six months followed by aspirin monotherapy lifelong. That is why most aneurysms treated are un-ruptured although there are cases where they were used for ruptured aneurysms also. Most centers still limit their use to the un-ruptured aneurysms. For adequate anticoagulation (and to lower the thromboembolic complications) prior to device placement, Plavix assays are checked at baseline before the administration of Plavix and then again just before the procedure. The percentage of inhibition is calculated and the dosage is adjusted to achieve adequate platelet inhibition before the procedure. Patients with resistance to Plavix are switched to a different anti-platelet drug.

After the routine groin access and placement of a sheath, the microcatheter is navigated inside the larger guide catheter to the desired position across the aneurysm neck. FD stent is then passed through the microcatheter and deployed across the aneurysm neck carefully under the angiographic guidance.

The coils don’t need to be packed as tightly, if at all, as in traditional aneurysmal coiling, which decreases the chances of mass effect from the large aneurysms (14). The results from the large retrospective and prospective single- and multi-center studies have shown an excellent feasibility of the treatment with a high efficacy and acceptable periprocedural complications (occurring soon before, during or after the performance of a medical procedure) as well as morbidity and mortality rates (17,18).

Besides the important complications such as thromboembolic events and the intra-procedural aneurysm rupture, which are also seen with traditional aneurysm coiling, other complications seen with the use of FDs include delayed aneurysmal rupture causing hemorrhage and distant (away from aneurysm) intraparenchymal hemorrhage. The mechanisms for delayed hemorrhage and distant intraparenchymal hemorrhage are not well understood. The hypotheses suggested include the inflammation associated with thrombus formation weakens the aneurysmal wall causing rupture or the hemodynamic changes within the aneurysm causing stress and rupture (14).

From the Retrospective Analysis of Delayed Aneurysm Ruptures (RADAR) study analysis, delayed aneurysms rupture after FDs use occurred in 1.0 percent of patients and delayed parenchymal hemorrhage was reported in 1.9 percent of patients (19).

Intrasaccular flow disruption with a WEB device is one of the latest technological advancements in management of wide-necked aneurysms especially at the bifurcation of an artery. The WEB device is placed within an aneurysm in contrast to the FDs which are placed in the parent artery. One of the biggest advantages is the reduced need for antiplatelet medications, especially for the ruptured aneurysms, which is particularly helpful in patients with SAH. The clinical experience with its use is currently limited; however, the preliminary retrospective multicenter series reported 100 percent technical feasibility, 4.8 percent morbidity and 0 percent mortality (20). The WEB device is not FDA-approved in the United States.

Which of the following findings should concern the EMT the most on assessing a patient who complains of a headache?

Which of the following is a characteristic of a focal onset aware seizure?

Which of the following most accurately describes the cause of hemorrhagic stroke?

Which criteria must be met for a patient to be considered as having status epilepticus?