Endovascular laser ablation is a minimally-invasive, one-hour procedure that replaces the surgical stripping and binding commonly associated with varicose vein treatment.  Unlike the traditional method, which many patients found very painful and required up to six weeks recovery time, laser vein ablation involves minimal discomfort and immediate recovery for most patients.This procedure is an option for treating greater saphenous vein incompetence, which causes varicose veins.  The laser used in the procedure destroys the greater saphenous vein, relieving the backflow pressure and allows the blood to flow in the right direction.  This eliminates the varicose vein and the pain caused by it.

Laser Vein Ablation

Laser Vein Ablation is an outpatient procedure performed in our office. After anesthetizing the skin, an ultrasound of the veins of the leg is performed. Using the ultrasound as a guide, a thin laser fiber is inserted into the vein. A highly concentrated beam of laser light is sent through the fiber, which eliminates the abnormal vein.

Endovascular laser treatment device

An endovascular laser treatment device preferably includes a catheter having a hub at its proximal end, an optical fiber for insertion into the catheter, a fiber connector attached to the optical fiber at a selected distance from the distal end of the optical fiber, and a temporary stop removably mounted around the optical fiber. The treatment device has two positions: a protective position and an operating position. As the fiber is inserted through the catheter, the temporary stop rests against the hub and places the fiber tip in the protective position where the distal end of the optical fiber is positioned near the distal end of the catheter, but is still disposed inside the catheter. When the temporary stop is removed and the fiber connector is coupled with the catheter hub, the fiber tip is in the operating position where the distal end of the optical fiber extends past the distal end of the catheter by a predetermined distance to expose the fiber tip.

Treatment

Laser therapy allows a specialist to seal veins closed and reroute the flow of blood to other veins deeper within the leg. The procedure itself requires only a few minutes, and a follow-up appointment will help confirm that the veins have completely closed.

UT Southwestern endovascular therapists also use sclerotherapy injections to treat larger varicose veins that do not respond to laser treatments. Both types of treatments are minimally invasive and typically require three to five appointments over a period of three to six months. For patients who are candidates for sclerotherapy, we will use a schlerosing solution or similar medical treatment to absorb the vein and eliminate its appearance.

Doctors often recommend these relatively new surgical procedures to patients who may not be able to withstand the stresses of major surgery, whether because of advanced age or because they have other serious medical conditions. However, these procedures are appropriate for less frail patients, too. Advantages include local or regional anesthesia instead of general anesthesia, shorter recovery time, less pain, smaller incisions, and less stress on the heart. These procedures may be used to treat aneurysms, cerebral vascular malformations, and arteries that have been occluded by plaque.

• Treatment of aneurysms: To repair an aneurysm, or a section of a vessel that has ballooned out, surgeons guide a coil (essentially, an artificial graft) into the damaged blood vessel and anchor it into place. This allows blood to flow normally again through the vessel, lowering the patient’s risk of a future hemorrhagic stroke. A long plastic tube called a catheter, which has been threaded up through a tiny incision in an artery in the thigh up to the trouble spot, is used to position the coil. X-ray imaging is used to guide the catheter.
• Treatment of cerebral vascular malformations: Endovascular surgeons may use a “superglue” substance introduced via a tiny catheter to eliminate or reduce the size of the cerebral vascular malformations. Often this facilitates further microsurgical or radiation treatment. Mechanical removal of blood clots: A new tool for treating hemorrhagic stroke is a tiny device used to physically remove blood clots that are blocking blood vessels within the brain. The Food and Drug Administration recently approved one such device, the Merci Retrieval System, which works like a corkscrew to pluck out clots. In nonbleeding (ischemic) strokes, blood clots damage the brain by depriving brain cells of the oxygen and nutrients (carried in the blood) they need to survive. But when used within the first several hours after a stroke, the device can extract clots and may reduce permanent damage.
• Angioplasty and stenting of vessels in the neck and brain: This new intervention is available at many medical centers. Cerebral angioplasty is similar to the widely used cardiology procedure, in which a tiny balloon attached to the tip of a catheter is threaded into a blocked artery and then inflated. In this case, the vessels are the carotid arteries in the neck, and a tiny tube-shaped bit of wire scaffolding, or a “stent,” is inserted into the blockage to keep it open after the balloon has been withdrawn. This procedure often is offered as an alternative to carotid endarterectomy for patients for whom the more invasive surgery is thought to be too risky, whether because of the patient’s overall health or because of the location of the blockage. Because angioplasty and stenting is fairly new, researchers are still investigating how well the stents hold up and how well the procedure reduces patients’ risk of stroke over the long term.
• Intra-Arterial Thrombolysis: For this procedure, doctors insert a small catheter into the blood vessels of the brain during cerebral angiography and deliver clot-dissolving medications directly to the blocked blood vessel.

Carotid endarterectomy

Carotid endarterectomy is a surgical procedure used to remove atherosclerotic plaque (fatty deposits associated with cardiovascular disease) from the carotid arteries. For selected patients who have had minor strokes or transient ischemic attacks (TIAs or ministrokes), carotid endarterectomy can be highly beneficial in preventing future strokes. The primary factor doctors consider when weighing this procedure for an individual patient is the extent to which plaque has narrowed the affected artery (“stenosis”). For patients with less than 50 percent stenosis, the benefits of carotid endarterectomy normally do not outweigh the risks. However, in patients with 70 to 99 percent

stenosis

 who have had recent symptoms caused by the stenosis, the surgery lowers the two-year risk of stroke by about 80 percent

Stereotactic procedures

Stereotactic techniques, which involve placing markers on the patient’s head to create reference points for very precise surgeries, allow surgeons to treat vascular malformations that were previously too difficult to reach. Stereotactic surgeries employ sophisticated computer technology in combination with MRI or CT scans to pinpoint the trouble spot. Using microscope-enhanced methods and delicate instruments, the surgeons can operate without affecting normal brain tissue.

Revascularization

Revascularization is a surgical technique for treating aneurysms or blocked cerebral arteries associated with atherosclerosis or moyamoya disease (a rare disease resulting in narrow or blocked vessels to the brain and irregular blood vessels). The technique essentially provides a new route of blood to the brain by grafting a blood vessel from the surface of the face near the temple to a cerebral artery through a hole in the skull.

Hypothermia

Preliminary studies with techniques that cool the brain or body suggest that doing so may improve outcomes for stroke patients in a variety of situations. Surgeons operating on stroke patients to correct cerebral vascular malformation and aneurysms, for instance, are finding that if they first chill the patient’s brain, he or she may be less likely to suffer another stroke during the surgery. Inducing hypothermia may also give the surgeon extra time to operate.Studies of patients who are comatose after a cardiac arrest have shown that chilling their entire bodies improves their chances of a favorable neurological recovery. This has led other doctors to try cooling down stroke patients. As with stroke, brain injury in cardiac arrest patients is caused by the interruption of the blood flow to the brain. Currently, doctors are trying to determine how long and to what degree the body should be cooled, and whether the risks of cooling outweigh the benefits in stroke patients.

What is the Endovascular treatment of aneurysms?

Coil embolization is an alternative to surgery. This treatment has been offered at Toronto Western Hospital since 1992. This is done in the Neuroangiography suite under fluoroscopy. The Neurointerventional radiologist will make a small incision in the groin through which a tiny catheter is guided through the femoral artery into the brain vessels. The catheter is carefully guided into the aneurysm. Soft platinum coils are deposited through the microcatheter into the aneurysm. When in position, the coil is released by an application of a very low voltage current causing the coil to detach from the pusher wire.

The softness of the platinum allows the coil to conform to the often irregular shape of an
aneurysm. An average of 5-6 coils are required to completely pack an aneurysm. The goal of
this treatment is to prevent blood flow into the aneurysm sac by filling the aneurysm with coils and thrombus. This should prevent aneurysm bleeding or re-bleeding.

Embolization does not repair areas of the brain already injured. The patient will be admitted either the night prior or the morning of the procedure. The treatment is done under a general anaesthetic. A minimum 2-night stay is required after the procedure.

The Procedure

Embolization is not an open surgical procedure and requires specialized training. Most endovascular therapists are neuroradiologists or neurosurgeons who have completed training (ranging from one to two years) in endovascular techniques after their medical (five years) and speciality training (five to seven years).

Before admission
Preadmission will be done one day or two prior to the embolization and routine blood tests may be done. After midnight, no food or drink is allowed.

The Day of the Procedure

After midnight, no food or drink is allowed. You will be taken from the “same day unit” or “preadmission area” to the Neuroangiography suite where the procedure will be performed. Just before the procedure, the nurses will shave one or both groins. Embolization is done under general anaesthesia. After the anaesthetic is administered, a catheter will be threaded up a blood vessel in your groin all the way up into the aneurysm. Very tiny catheters are used. This is a similar procedure to a cerebral angiography except that in addition to dye being injected to show the aneurysm, these tiny catheters are positioned near the aneurysm and platinum coils are inserted into the aneurysm to embolize it.

The length of the procedure is often not predictable, and waiting family members need not to be frightened because a case may takes longer than expected. If the doctors do not think that they can safely embolize the aneurysm, then the embolization procedure will be discontinued.

After Treatment

You will be taken to the Neurosurgical Intensive Care Unit or Step-down Unit where you will be observed closely overnight. Your doctor will instruct you to remain still, lying flat in bed for up to eight hours. This rest period allows the groin artery to heal.

If all goes well, you will be transferred to a neuroscience floor the next day and discharged home the following day. Most patients treated by embolization will also need to return for a follow-up angiogram or magnetic resonance angiogram (MRA), usually performed several months after the treatment to confirm that the outcome of the treatment is stable in time.

What are the Side Effects?
 

The risk of embolization is low. Possible complications include stroke like symptoms such as weakness in one arm or leg, numbness, tingling, speech disturbances and visual problems.Serious complications such as permanent stroke or death are rare.The estimated risk should be discussed with your doctor.

 
Detachable balloon occlusion

Sometimes the size, shape or location of an aneurysm makes coil embolization and surgery impossible. In this case the doctor may choose to block off the parent artery itself. A preliminary test occlusion is often required. A balloon occlusion of the parent artery may be required for an aneurysm at the base of the skull or a very large aneurysm.

A detachable balloon may be placed distal and proximal to the aneurysm. This will permanently close the artery, therefore no blood will reach the aneurysm. The patient is often tested in advance to assure he can tolerate the occlusion of the artery. This is called a balloon test occlusion.

Introduction

Endovascular approaches are being increasingly utilized to treat a variety of thoracic aortic pathologies, including aneurysms, dissections, and transections . Ongoing challenges to endovascular strategies for thoracic aortic pathology include relatively restricted endoprosthesis configurations, lack of FDA-approved devices of appropriate size for the small thoracic aorta, and problems associated with endovascular access. Here we present a case of a descending thoracic aortic pseudoaneurysm treated with a tapered endoprosthesis that illustrates a number of these challenges.

Case Presentation

The patient is a 33 year old male with a history of juxtaductal coarctation who underwent a repair early in infancy. The patient had a recurrence of the coarctation and underwent a second open repair and left diaphragm plication at 2 years of age. He was lost to follow-up until recently when he presented to an emergency room with a several week history of hemoptysis and left back pain. The patient’s physical exam was remarkable only for a well-healed left thoracotomy incision. The patient was afebrile with equal blood pressures in all 4 extremities. The patient’s white count was normal. A CT scan of the chest demonstrated a saccular aneurysm of the proximal descending thoracic aorta measuring approximately 6cm in diameter . The patient was transferred to the Oregon Health and Sciences University for further management.
At our institution a dedicated CT angiogram of the chest was obtained to better define the morphology of the patient’s arch and aneurysm. This confirmed the finding of a saccular aneurysm just distal to the left subclavian artery takeoff. Because of the patient’s prior history of coarctation recurrence and repair, this was felt most likely to represent a pseudoaneurysm, possibly at the site of a patch repair. Aortic reconstructions of the CT angiogram showed no evidence for recurrence of the coarctation . There was, however, a size discrepancy in the diameter of the aorta above and below the aneurysm. The diameter of the aortic arch between the left carotid and left subclavian arteries was 13mm. The diameter of the descending thoracic aorta distal to the aneurysm was 23mm.

Because of the patient’s prior coarctation repairs and the morphology of the pseudoaneurysm, an endovascular repair was felt to be desirable. Based on preoperative measurements of the CT angiogram, a tapered endoprosthesis 9.5cm in length with 16mm proximal diameter and 20mm distal diameter (W.L. Gore & Associates, Inc.), originally marketed as an iliac limb, was selected for use. The patient was taken to the operating room. After induction of general anesthesia, percutaneous right femoral artery access was obtained and a measuring pigtail catheter was advanced into the distal aortic arch. An aortogram was performed which demonstrated the aortic arch and pseudoaneurysm morphology .

At our institution a dedicated CT angiogram of the chest was obtained to better define the morphology of the patient’s arch and aneurysm. This confirmed the finding of a saccular aneurysm just distal to the left subclavian artery takeoff. Because of the patient’s prior history of coarctation recurrence and repair, this was felt most likely to represent a pseudoaneurysm, possibly at the site of a patch repair. Aortic reconstructions of the CT angiogram showed no evidence for recurrence of the coarctation . There was, however, a size discrepancy in the diameter of the aorta above and below the aneurysm. The diameter of the aortic arch between the left carotid and left subclavian arteries was 13mm. The diameter of the descending thoracic aorta distal to the aneurysm was 23mm.

Because of the patient’s prior coarctation repairs and the morphology of the pseudoaneurysm, an endovascular repair was felt to be desirable. Based on preoperative measurements of the CT angiogram, a tapered endoprosthesis 9.5cm in length with 16mm proximal diameter and 20mm distal diameter (W.L. Gore & Associates, Inc.), originally marketed as an iliac limb, was selected for use. The patient was taken to the operating room. After induction of general anesthesia, percutaneous right femoral artery access was obtained and a measuring pigtail catheter was advanced into the distal aortic arch. An aortogram was performed which demonstrated the aortic arch and pseudoaneurysm morphology.

The length of the delivery catheter of the selected tapered endoprosthesis to be used for pseudoaneurysm repair was noted to be 55cm. Based on patient measurements using the right femoral measuring pigtail catheter, it was clear that the endoprosthesis delivery catheter was of insufficient length to allow deployment from the left common femoral artery. A 3cm transverse incision was therefore made over the left external iliac artery. The left external iliac artery was controlled and the patient was heparinized. An 18 Fr sheath was advanced from the left external iliac artery into the distal aorta.

Selective angiography of the left subclavian artery was performed to confirm an intact posterior cerebral circulation. The proximal left subclavian artery was occluded with two 10mm Amplatzer vascular plugs which were introduced via the left external iliac sheath. An angiogram of the distal aortic arch and descending thoracic aorta was then performed to obtain a roadmap of the proximal and distal landing zones . 

The tapered endoprosthesis was passed through the left external iliac sheath, positioned appropriately under fluoroscopic guidance, and deployed. An arch angiogram showed good endoprosthesis placement. Because of the relatively short proximal landing zone length (1cm), a 10 x 40mm Palmaz stent was placed and ballooned to 16mm proximally to achieve good radial fixation. The distal end of the endoprosthesis was ballooned. Completion angiography showed occlusion of the left subclavian artery and exclusion of the pseudoaneurysm .

The patient had an uneventful postoperative course. He had no left arm symptoms. A postoperative CT scan showed good placement of the endoprosthesis and vascular plugs and no endoleak . The patient was discharged to home on postoperative day 2 .

Endovascular brachytherapy (EBT) is a treatment modality to prevent restenosis, which is when after a blood vessel stenosis has been opened by angioplasty, it becomes blocked again. It has been proven that radiation prevents restenosis. Endovascular brachytherapy can be used for cardiac blood vessels and in extremities. In coronary endovascular brachytherapy, sources are inserted into the coronary arteries. These sources have a much lower strength than HDR sources, but radiation safety is still a critical issue in this multidisciplinary endeavour. There are several types of sources used in EBT, such as double-layered balloon catheters with a radioactive coating between the layers, balloon catheters filled with a radioactive liquid or gas and radioactive stents. These sources are generally used for coronary endovascular brachytherapy, but standard remote afterloading devices with gamma-emitting radionuclides can be used for peripheral endovascular brachytherapy. Since irradiation is targeting to parts of the arterial wall to a depth of 0-3 mm, sources are mainly beta ray or low-energy gamma ray radionuclides

Is my treatment lab sufficiently shielded for EBT?

A qualified expert in radiotherapy physics should determine this.

It is common for EBT for coronary arteries to be performed in catheterisation labs, which might not have been initially designed for radioactive materials, but to protect against X radiation. If beta sources are used in the treatment, no room shielding is generally needed but if gamma ray sources are used it is likely that shielding will be needed. In particular, some endovascular treatment of peripheral vessels might be performed using standard HDR brachytherapy equipment, which would necessitate dedicated HDR treatment rooms with high shielding requirements. A qualified expert in radiotherapy physics should be engaged to ascertain the fulfilment of shielding requirements.

How do I know that the source has been placed in the correct location in the patient?

The actual position of the source inside the patient should be verified by fluoroscopy.

A radiation survey outside the patient is not sufficient. If there is a discrepancy between the planned and the actual location that cannot be rectified by further source movement, but by pulling the source back into the delivery device. Before putting the catheter in place, it a visual inspection is needed, also for mechanical integrity using a non-active dummy source. Kinks in the catheter may lead to accidental exposure, as shown in reports of catheter kinks leading to unintended dose distributions in endovascular brachytherapy.

Is there a risk of calculation mistakes leading to unintended absorbed dose?

Yes – you should ensure independent verification of calculations.

As in all radiotherapy, there is a risk of mistakes in the calculation of treatment times. An example of this was reported (IAEA TECDOC 1488) where the diameter of the artery was used for calculation purposes instead of the intended radius, causing a near doubling of the intended absorbed dose to the patient. Endovascular brachytherapy is a discipline where the time between determination of treatment parameters, treatment planning and treatment delivery is very short and, thus, where there is a potential for mistakes being made due to unclear communication. As always, calculations need to be independently verified.

What should I do if the normal return movement of the EBT source fails?

You should follow the local emergency procedure.

It is very important that a local emergency procedure is put in place for this type of emergency situations, already as part of the clinical commissioning of the EBT procedure. This procedure should be well posted, known by staff and tests should be performed.Source return can fail due to breakdown of power backup, failure of mechanics or obstructions in the catheter. The built-in emergency source retraction system should be used to position the source inside the storage container of the delivery device. It is important that persons not directly involved in the emergency procedure leave the room.

What if the emergency source retraction system also fails to retract the source?

You need to manually remove the source from inside the patient.

It should be noted that availability of appropriate emergency containers in the treatment room is always needed –

plastic shielded containers for beta sources and lead containers of appropriate thickness for gamma sources.An emergency procedure is needed, containing the following instructions: Try to locate the source by using X ray fluoroscopy.and remove the catheter from the patient, taking care to avoid touching the catheter near the active source. Use emergency equipment, such as forceps, tongs or tweezers, to move the catheter to the emergency container (which might be handled by another person for practical reasons). It is important that persons not directly involved in the emergency procedure leave the room.

Evidence for Endovascular Repair

Two randomized European trials comparing EVAR to open surgery (OS) and 1 randomized trial comparing EVAR to no intervention were published in 2005.The first was the Dutch Randomized Endovascular Aneurysm Management (DREAM) trial, randomizing 351 patients with asymptomatic AAAs >5 cm in diameter with suitable stent graft anatomy to OS or EVAR. This study suggested a 30-day benefit in mortality favoring EVAR (1.2% EVAR versus 4.6% OS; P=0.10).The trend toward an early mortality advantage was lost, however, 12 months into the 2-year study follow-up.

The second trial, from the United Kingdom, labeled EVAR trial 1 (EVAR 1) was similar to DREAM in comparing EVAR to OS in patients with suitable stent graft anatomy and aneurysm size 5.5 cm.28 This study randomized a large group of patients (1082), with 94% receiving their allocated treatment. EVAR 1 more clearly demonstrated an early perioperative mortality benefit for EVAR (1.7% EVAR versus 4.7% OS; P=0.009).31 Blood product use and length of hospital stay also favored EVAR. In contrast, the primary end point of all-cause mortality did not show a lasting benefit for EVAR at the 4-year study conclusion, although aneurysm-related death was decreased (3.5% EVAR versus 6.3% OS; P=0.02). Complication rates (17.6 per 100 person-years EVAR versus 3.3 per 100 person-years OS; P<0.0001) and reintervention rates (6.9 per 100 person-years EVAR versus 2.4 per 100 person-years OS; P<0.0001) were much higher for stent graft repair than for open repair.

EVAR trial 2 (EVAR 2) randomized 338 patients >60 years of age with aneurysms 5.5 cm who were deemed unfit for open surgical repair to EVAR or no intervention. Between the 2 arms of the study, 142 patients died during follow-up, which correlated to a 64% overall mortality by Kaplan–Meier estimates at 4 years. This study was complicated by long delays in EVAR after randomization and a 27% patient crossover rate from the no intervention group. In the final analysis, no benefit to EVAR over medical management was detected in either overall mortality or aneurysm-related mortality for patients unfit for open surgery.

Ongoing in the United States is the Open Versus Endovascular Repair (OVER) trial, a 9-year study that began in 2002 comparing endovascular aneurysm repair with standard open surgery using a multicenter randomized trial through the Department of Veteran Affairs (VA) Cooperative Study Group.

Clinical Use

The FDA approved the transluminal stent graft treatment of abdominal aortic aneurysms in 1999. Whereas 2 devices were initially approved, AneuRx by Medtronic (Minneapolis, Minn) and Ancure by Endovascular Technologies Inc (EVT; Menlo Park, Calif), the Ancure device was removed from the market in 2001 after the company failed to submit >2500 medical device reports to the FDA. Three additional devices now also hold FDA approval, including the Zenith (Cook Inc, Bloomington, Ind), Excluder (W.L. Gore and Associates, Flagstaff, Ariz), and Powerlink (Endologix Inc, Irvine, Calif) systems. Multiple other stent grafts bearing the CE (Conformité Européenne) mark are employed in Europe after demonstrating safety for their intended use. Many stent grafts have undergone modification, with resulting technologies in the third generation and beyond. Despite the diversity among the devices, a generalized discussion of device implantation is indicated.

Preprocedural planning is the most critical component of a technically successful endovascular abdominal aortic aneurysm repair. CT provides the backbone for evaluating patient candidacy. In addition to the indications of either an asymptomatic aneurysm of appropriate maximal diameter, or a small aneurysm with features putting it at increased risk of rupture, patients being considered for EVAR must fulfill several anatomic criteria. These include -

•  lliofemoral access vessels that will allow safe insertion and deployment of the device, adequate seal, and sufficient length to provide axial support for the graft
• An infrarenal aortic neck of adequate length, limited angulation, and appropriate diameter. These anatomic features, as well as the presence or absence of thrombus and calcium at each level, can be evaluated using CT.

Complications of Endovascular Aneurysm Repair

The numbers of adverse events possible with EVAR are many, because it is a technically complex procedure typically performed on a high-risk patient population. One of the most common adverse events is the need for a secondary intervention of some type. Data from the EUROpean collaborators on Stent/graft Techniques for aortic Aneurysm Repair (EUROSTAR) registry of 2846 patients treated from December 1999 until December 2004 revealed that EVAR resulted in a cumulative incidence of secondary interventions of 6.0%, 8.7%, 12%, and 14% at 1, 2, 3, and 4 years, respectively. Secondary interventions are typically performed when the aneurysm sac has become repressurized because of incomplete exclusion of blood flow from the sac. The term “endoleak” was created to describe this complication in 1996, and a classification scheme has been adopted.Type I and type III endoleaks are treated with immediate intervention to halt perigraft flow or flow between modular components. Type II endoleaks are typically managed expectantly with intervention reserved for persistent endoleaks in the presence of aneurysm sac enlargement. The presence of a persistent type II endoleak for 6 months, however, has been associated with aneurysm enlargement, increased rate of secondary interventions, and even aneurysm rupture. Type IV endoleaks rarely occur with modern stent graft design, and type V endoleaks (endotension), although still reported, are much less frequent after modification of the Gore Excluder device in 2004 to a low-permeability expanded polytetrafluoroethylene layer. Secondary interventions occur in a spectrum ranging from diagnostic angiography to endograft removal with conversion to open repair, although the majority are percutaneous treatment of type II endoleaks with source embolization.
A related cause of endoleak and potential complication of EVAR is device failure. The integrity of stent graft materials and maintenance of proper positioning within the aneurysm are critical in preventing pressurization of the aneurysm sac and rupture. Material failure includes fracture of any of the metallic components of the stent graft, including stents, hooks, or barbs, or tears in the fabric component of the stent graft. Loss of proper stent graft position can occur for many reasons. Material failure, inadequate proximal or distal seal zone, aneurysm remodeling after EVAR, or features of the vessel, such as thrombus or calcium, that limit stent purchase, have all been implicated in the migration of stent grafts. Each of these modes of failure needs to be analyzed within the context of their clinical significance. A stent fracture that leaves the graft fabric intact and is not in a critical region for maintaining fixation would likely need only follow-up, whereas modular component separation resulting in a large type III endoleak will require urgent intervention to restore stent graft integrity.

Approach to the Small Abdominal Aortic Aneurysm

Whereas randomized clinical trials have focused on establishing the proper use of EVAR for larger aneurysms, its application for the treatment of small aneurysms is still an area of controversy. Early open aneurysm repair for aneurysms <5.5 cm in diameter does not confer a long-term survival advantage. However, retrospective analysis of the large EUROSTAR database revealed that EVAR for aneurysms with diameters between 4.0 cm and 5.4 cm had lower incidence of type I endoleak and improved cumulative freedom from aneurysm-related death relative to 2 comparison groups with aneurysm diameters of 5.5 to 6.4 cm and 6.5 cm. Level 1 evidence is lacking at this time, but the Positive Impact of EndoVascular Options for Treating Aneurysms EarLy (PIVOTAL) and Comparison of surveillance versus Aortic Endografting for Small Aneurysm Repair (CAESAR) trials were initiated in an attempt to provide such evidence. Both are device specific, randomize patients with smaller aneurysms to EVAR or surveillance, and use an FDA-approved Medtronic device or the Cook Zenith device, respectively. Until the results of these trials are published, the optimal management of small aneurysms remains ambiguous and a patient-specific approach that takes into account aneurysm morphology, biology, and patient comorbidities should be used.

Published Clinical Guidelines

The 2005 American College of Cardiology/American Heart Association practice guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic) states that it is reasonable to offer EVAR of infrarenal aortic and/or common iliac aneurysms in patients at high risk of complications from open operations because of cardiopulmonary or other associated diseases and that repair may be considered in patients at low or average surgical risk. Whereas this document proposes a treatment algorithm setting the threshold for surgical repair at 5.5 cm except in cases of rapid expansion, it also states, “Ultimately, once an infrarenal aortic aneurysm reaches an appropriate size for graft replacement, a choice must be made between a traditional open operation or endovascular repair. Like all other aspects of aneurysm management, this decision requires a balanced judgment of relative risks.” Other features, such as saccular aneurysm morphology, patient gender, heredity, uncontrolled hypertension, and chronic obstructive pulmonary disease may also be important considerations.

 Conclusions

The patient described in the vignette meets all the recommended criteria for aneurysm repair. His age, ethnic background, and heavy smoking history are typical of patients with this disease process. The absolute aneurysm size and history of rapid expansion suggest that repair would offer a mortality benefit. Before offering EVAR, however, anatomic suitability must be confirmed by an experienced clinician using accurate imaging. Once it is established that the patient is an appropriate candidate for endovascular repair, the risks and benefits of both open and endovascular approaches should be discussed. Given the advanced age and pulmonary morbidity of this patient, endovascular repair would be appropriate therapy.

Introduction

The early 1990s ushered in the era of endovascular aneurysm repair (EVAR). Diffusion of this technology, although widespread, has been met with enthusiasm by some and caution by others. Advocates of traditional open surgical techniques maintain that EVAR is costly and that long-term outcomes for patients are inferior. The objectives of the present review are to use a case scenario to highlight the clinical problem, examine current data on the use of EVAR, and to describe the principles behind the safe application of this therapy to patients.

Case Scenario

A 78-year–old white man involved in a motor vehicle crash is evaluated in the emergency department and is found to be without serious injury. Computerized tomography (CT) reveals the incidental finding of a 4.8-cm infrarenal abdominal aortic aneurysm. He has been unaware of the aneurysm but recalls an older brother who had undergone repair of an aneurysm previously. He smokes 2 packs of cigarettes daily, has moderate chronic obstructive pulmonary disease, and has hypertension that is well controlled on a β-Blocker. He is referred to a vascular surgeon, who recommends ultrasound surveillance with a 6-month follow-up visit. The subsequent visit reveals aneurysm growth to 5.6 cm, which is confirmed by repeat CT. The patient remains asymptomatic and endovascular aneurysm repair is offered.

Clinical Impact of Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a significant health risk in older populations, representing the 14th-leading cause of death for the 60- to 85-year–old age group in the United States. Necropsy studies from Europe and the United States suggest an overall prevalence of the condition of 2% to 4% for men and 1% to 2% for women. The prevalence is greatly affected by case definition, however, with less stringent definitions of AAA in population-based screening studies demonstrating a prevalence of nearly 9% in men and 2% in women. Universally noted are the graded increase in prevalence with advancing age and the increased prevalence with male gender.

Noninvasive screening programs and a dramatic rise in the elderly population have led to an overall increased incidence of asymptomatic AAA. Despite an aggressive surgical posture toward elective repair before rupture, the incidence of ruptured AAA has also continued to increase.Annually 35 000 to 40 000 aneurysms are repaired surgically in the United States.A steady upward trend in stent graft use reflected in administrative databases implies that EVAR now represents the majority of cases.1 With Markov modeling of hospital costs ranging from $16 016 to 18 484 for open repair and $20 083 to 20 716 for EVAR, AAA represents a considerable economic burden.

Pathophysiology and Current Therapies

AAAs are conventionally defined as a 50% increase in aortic diameter compared with the normal proximal aorta. The inciting events leading to AAA formation are not well understood. Some common themes of maturing aneurysms include 

•  proteolytic degradation of aortic wall
• connective tissue 
•  transmural inflammation immune responses
•   increased biomechanical wall stresses
   
  Once AAA formation is initiated, a slow steady growth of the aneurysm until rupture is typical, although on an individual basis this growth rate may be quite variable. Larger-diameter aneurysms in particular, along with female gender, advanced age, smoking, and hypertension have been associated with rapid growth. Rapid growth has consequently been associated with increased risk of rupture, although initial aneurysm size at diagnosis has the strongest association with rupture. Open aneurysm repair, initially using homografts, has successfully been employed to prevent rupture since the 1950s. The traditional open surgical approach in the modern era is performed either via a retroperitoneal or transperitoneal exposure to obtain proximal and distal aortic control. The aneurysm is then opened, back-bleeding branch arteries are ligated, and a prosthetic graft is sutured from the normal proximal aorta to the normal distal aorta or iliac segments. Flow is then restored to the lower extremities and the aneurysm sac is closed over the newly placed synthetic graft. Although effective and durable in treating aneurysms and preventing rupture, this operation has been associated with national mean mortality rates> 4% since the 1980s.

The excessive mortality associated with open aneurysm repair and a strong trend in surgery toward minimally invasive techniques led to the concept that a covered stent graft might be delivered endoluminally, effectively sealing off the aneurysm wall from systemic pressures, preventing aneurysm rupture, and decreasing associated mortality. In 1991, the first published report of stent graft implantation for AAA in humans suggested that this approach was feasible. Subsequent years have seen a tremendous surge in both the number of endovascular aneurysm repairs performed and technological improvements in stent graft design. Four Food and Drug Administration (FDA)–approved devices, each with a slightly different design, are currently being marketed . Rather than relying on sutures to provide fixation, as in open repair, endovascular stent grafts rely on radial forces of self-expanding stents for fixation or self expand in concert with active fixation using hooks or barbs at the proximal aorta fixation site. One FDA-approved device uses bare-wire suprarenal support, as well. With appropriate positioning and adequate fixation, each of these devices redirects the transmission of aortic pulsatile flow and shear forces from the wall of the aneurysm sac to the graft itself. The responses of aneurysm sacs to these changes are variable. The great majority will cease growth or shrink over time. With longer follow-up now being achieved after EVAR, >97% 5-year and >94% 9-year rupture-free survival has been observed.

Background And  Purpose:

Peripheral aneurysms of the posterior inferior cerebellar artery (PICA) are rare, and pre-existing literature concerning their endovascular treatment is limited. The purpose of this study was to assess the etiology and clinical characteristics of peripheral PICA aneurysms and to evaluate the angiographic and clinical results of the patients who underwent endovascular treatment for a peripheral PICA aneurysm in a single center.

Material And  Methods:

 Twelve consecutive patients with 12 peripheral PICA aneurysms (10 ruptured) included in an internal data base were retrospectively reviewed. Posttreatment and follow-up angiograms were analyzed, and the clinical outcome was recorded.

Results:

The etiology was dissection in 7 (58%) and unknown in 5 cases (42%). Three dissecting aneurysms reruptured before endovascular treatment, and another 3 demonstrated angiographic progress. Four aneurysms were treated by endosaccular coiling, 6 (all dissecting) by parent artery occlusion, and in 2 cases endovascular treatment failed. Angiographic outcome was complete aneurysm and/or parent artery occlusion in 9 cases and neck remnant in 1 case. One aneurysm needed retreatment at follow-up. One lethal procedural complication occurred, and transient ischemic symptoms appeared in 2 patients. The clinical outcome was good in 7 patients, whereas 3 patients, all poor clinical grade, died (1 for unrelated reasons). No rebleedings have occurred during the follow-up.

Conclusion:

In this series, most peripheral PICA aneurysms were secondary to arterial dissection. They were unstable with a high risk of rebleeding and a high mortality if not treated without delay. Endovascular treatment was effective in preventing rehemorrhage.

What can I expect after endovascular stent grafting?

Usually you will spend 2 to 3 days in the hospital. During the first recovery day you will be permitted to eat and encouraged to walk. After you leave the hospital, you should not drive until your physician approves. You may be permitted to sponge bathe around your incisions but you should avoid soaking your groin incisions until they have healed. You may also be advised to avoid lifting more than about 5 to 10 pounds for approximately 4 to 6 weeks after the procedure.

Your physician will instruct you to return for a follow-up visit after about 7 to 10 days. At that visit, your physician will check your incisions and assess your overall condition. Usually you will undergo follow-up imaging tests 1 and 6 months after the procedure to ensure that the stent is still functioning without significant problems and in the proper location. After the first year, you will probably undergo yearly imaging tests if your aneurysm is shrinking and no problems are found. You may require more frequent imaging tests if potential problems require closer monitoring. 

Are there any complications?

The potential complications of endovascular stent grafting include:

• Leaking of blood around the graft (“endoleaks”)
• Infection
• Movement of the graft away from the desired location (“migration”)
• Graft fracturing
• Blockage of the blood flow through the graft
  Sometimes fever and an increase in white blood cell count can happen shortly after endovascular stent grafting. These symptoms usually last 2 to 10 days and are treated with medications such as aspirin and ibuprofen. Other complications that are rare but serious include a burst artery, injury to your kidney, paralysis, blocked blood flow to your abdomen or lower body, and delayed rupture of AAA.

Endovascular stent grafts can sometimes leak blood through the areas where the graft components join together, or they can allow blood to leak back into the aneurysm sac through small arteries feeding the aneurysm sac. These leaks are called “endoleaks”. Some of the leaks stop by themselves and are not dangerous, but others need to be treated immediately. These leaks can even occur years after your procedure and can be dangerous if the aneurysm continues to enlarge. Thus, after endovascular aneurysm repair, physicians require their patients to undergo long term surveillance with periodic CT scans for the rest of their life to detect and treat problems before they become threatening. Since problems with the graft or endoleaks can occur even years after successful placement, it is important to comply with the follow-up regimen advised by your vascular surgeon.

If you suspect or experience any complications because of the endovascular stent graft as described above, you should contact your physician immediately.

What is an endovascular stent graft?

An endovascular stent graft is a tube composed of fabric supported by a metal mesh called a stent.  It can be used for a variety of conditions involving the blood vessels, but most commonly is used to reinforce a weak spot in an artery called an aneurysm. Over time, blood pressure and other factors can cause this weak area to bulge like a balloon and it can eventually enlarge and rupture. The stent graft is designed to seal tightly with your artery above and below the aneurysm. The graft is stronger than the weakened artery and it allows your blood to pass through it without pushing on the bulge. Physicians typically use endovascular stent grafting to treat abdominal aortic aneurysms (AAAs), but they also use it to treat thoracic aortic aneurysms (TAAs) and less commonly, aneurysms in other locations.

Aneurysms often affect the aorta, your body’s largest artery. Your aorta carries blood away from the heart and it runs from your heart through your chest and abdomen. The normal diameter of the aorta in the abdomen is about 2 centimeters, which is a little less than 1 inch. An aneurysm is considered to have formed if the aorta grows to more than 1½ to 2 times its normal diameter.

Aortic aneurysms are potentially serious health problems since a burst aorta results in massive internal bleeding that can be fatal unless treated rapidly by an experienced emergency medical team. Endovascular stent graft repair is designed to help prevent an aneurysm from bursting. The term “endovascular” means “inside blood vessels.” To perform endovascular procedures, vascular surgeons use special technologies and instruments. These procedures require only a small incision or puncture in an artery or vein. Through these punctures, a vascular surgeon inserts long thin tubes, called catheters, which carry the devices through your blood vessels to the location of the aneurysm where they can be placed to reline and strengthen your artery. Generally, endovascular treatments allow you to leave the hospital sooner and recover more quickly, with less pain and a lower risk of complications, and sometimes a lower risk of death, than traditional surgery because the incisions are smaller. Sometimes traditional surgery is required, however, if the shape or the location of the aneurysm is not favorable for an endovascular treatment.  Your vascular surgeon will help you decide what procedure is best for your particular situation.

How do I prepare?

Your physician will ask you about your medical history and perform a complete physical examination. In addition, your physician may perform several tests, including an electrocardiogram (ECG), which measures your heart’s electrical activity, stress testing, which will help to determine your heart health and a scan to determine if your aneurysm has a favorable shape for endovascular stent graft treatment. If your physician believes that you are a good candidate for endovascular stent grafting, he or she may order one or more of the following tests. These tests show detailed images of your arteries and help your physician choose the correct size and shape of the graft

Spiral computed tomography (CT) scan: This test involves a rapid series of x rays taken in a spiral pattern around your body. A computer transforms the x ray data into three-dimensional images of your blood vessels.
Angiography: In these tests, your physician inserts a catheter into one of your arteries. Your physician then injects a dye called contrast through the catheter and takes x rays.

Am I eligible for endovascular stent grafting?

You may be eligible for elective (non-emergency) endovascular stent grafting if your aortic aneurysm has not ruptured, is large enough (5 centimeters, about 2 inches, wide or more), and you have a long enough area of normal artery for the stent graft to attach securely.  Endovascular stent grafting may be a good option if your risk for conventional surgical aneurysm repair is increased because of other illnesses you might have.  However, if you have a long life expectancy or have a low risk for complications, or if the shape of the aneurysm is not favorable for an endovascular stent graft, your physician may recommend conventional surgical aneurysm repair instead. To date, this treatment has been used for a longer period of time than endovascular stent grafting and there is general agreement that it requires less long-term maintenance than endovascular repair.

The physical characteristics of your aneurysm help your physician determine if you are a good candidate for endovascular treatment. For example, if you have an AAA located in the section of the aorta just below your kidney arteries, and there is enough space for the stent graft to seal properly, and your aorta is not severely angled, you may be eligible. Your blood vessels also must be large enough to allow the endovascular stent graft to pass through, and the device must fit the shape and contour of your blood vessels once it is in place.

Am I at risk for complications?

If you have kidney disease called chronic renal insufficiency, your chances of complications from endovascular stent grafting may be increased since contrast dye, which can affect the kidneys, is required. If you have an unfavorable aneurysm shape, associated arterial occlusive disease, or have already had an AAA repaired, you also may be at increased risk for complications. Other conditions, such as heart or lung disease, may also increase the risk for treatment.  Some of these issues may be addressed by adjunctive measures to lessen the risk of the endovascular procedure if your risk for conventional (open) aneurysm repair is prohibitive.  Your vascular surgeon will advise you regarding the best option for your particular situation. 

What happens during endovascular stent grafting?

As the procedure begins, you will usually receive a sedative and a regional anesthesia, or you might receive general anesthesia depending upon your particular circumstance. Your vascular surgery team will clean your skin and shave hair around the insertion points to help decrease your chances of infection. Your vascular surgeon will then cut into the skin overlying the femoral artery in your groin. Your vascular surgeon then threads a guide wire into your femoral artery and advances it to the aneurysm. Because you have no nerve endings inside your arteries, you will not feel the wires or catheters as they move through your body. You may feel a slight pressure or a sensation of mild tugging during this insertion.

Using x-rays that appear as moving images on a screen, your vascular surgeon inserts a catheter over the guide wire. Usually your vascular surgeon will perform angiography through the catheter to insure correct placement of the endovascular stent graft.  You may feel a warm sensation as the contrast dye is injected.  Then, a compressed form of the graft is inserted through a larger catheter, called a sheath, and the guide wire carries so it can move through your blood vessels. When the graft has reached the aneurysm site, your physician withdraws the sheath, leaving the graft in place. The graft expands to fit snugly against the walls of your artery. Often additional components of the graft are placed in a similar fashion through incisions in each groin to extend to the arteries supplying each leg.