Cardiology

Aortic Aneurysm Intervention

General description of procedure, equipment, technique

General description of the procedure and its role in treatment of cardiac disease:

  • Endovascular stent graft placement across abdominal aortic aneurysm (AAA) and thoracic aortic aneurysm (TAA) is the preferred mode of treatment in patients with aortic aneurysms.

  • The device is placed via the femoral access percutaneously or surgical cutdown under fluoroscopic guidance under anesthesia.

Endovascular aortic aneurysm repair (EVAR): There are four different kinds of stent grafts that are approved for use in the U.S.

  1. Medtronic Talent and AneuRx (Medtronic Corp., Minneapolis, MN)

  2. Zenith FLEX AAA endograft (Cook Medical Inc., Bloomington, IN)

  3. Gore Excluder (W.L. Gore and Associates, Inc., Flagstaff, AZ)

  4. Endologix Powerlink (Endologix, Inc., Irvine, CA)

  • The basic EVAR system consists of three components: delivery system, stent graft and fabric sleeve for exclusion of the aneurysm.

  • All the three grafts a, b, and c have the modular design consisting of main body ipsilateral iliac graft and a contralateral graft attached to the main body as a second component.

  • The Endologix device has the unique Unibody aortic graft with bilateral iliac extension and main body stent graft.

EVAR is performed for patients with large AAA(>5.5 cm) and symptomatic AAA. Other conditions that can benefit from EVAR are:

AAA >5.0 cm in women

  • Ruptured AAA

    • Symptomatic infrarenal aortic penetrating ulcer

    • Aortic pseudoaneurysm

    • Common and external artery iliac aneurysms >3.0 cm

    • Internal iliac artery aneurysms >3.0 cm

TEVAR : Currently three approved devices are available in the U.S.

  1. Gore (W.L. Gore and Associates, Flagstaff, AZ)

  2. Medtronic Talent, Medtronic Valiant and Captiva (Medtronic Corp., Sunnyvale, CA)

  3. Cook Zenith Tx1 and Tx 2 endograft (Cook Medical, Bloomington, IN).

TEVAR is used to treat patients with TAA >6.0 cm and those with symptoms.

Other conditions that may benefits from TEVAR are:

  • Type B aortic dissection

  • Postcoarctation repair aneurysm

  • Penetrating ulcer

  • Pseudoaneurysm of descending aorta

  • Transection of the descending aorta

  • Ruptured TAA

    • The stent graft is placed distal to the renal and left subclavian artery in patients with AAA and TAA respectively.

    • The stent graft will completely exclude the aneurysm and preserve distal flow.

Indications and patient selection

  • Any symptomatic abdominal and thoracic aortic aneurysms should be treated irrespective of the size.

  • Asymptomatic abdominal aortic aneurysms (AAA) and thoracic aortic aneurysms (TAA) should be considered for revascularization based on the size.

  • AAA in men and women >5.5 cm and TAA >6.0 cm should undergo elective revascularization.

  • AAA and TAA are defined as rapidly expanding when growth is more than 1 cm in anterio-posterior diameter over 12 months or 0.5 cm over 6 months.

  • Women tend to have small caliber aorta and early chance of rupture compared to men. In women, AAA >5.0 cm and TAA >5.5 cm should be considered for EVAR and TEVAR.

  • Patients with connective tissue disease such as Marfan syndrome are usually treated with percutaneous revascularization at 5.0 cm for AAA and 5.5 cm for TAA .

  • Ruptured AAA and TAA with suitable anatomy should be considered for EVAR and TEVAR.

  • Pseudoaneurysms of the thoracic aorta and infrarenal abdominal aorta should be considered for percutaneous revascularization.

  • Mycotic aneurysms in patients who are surgical high risk due to comorbidities may benefit from EVAR and TEVAR.

  • Thoracic traumatic injury resulting in partial or full transection of thoracic aorta should be managed with TEVAR.

  • Symptomatic or large penetrating ulcers of the thoracic and infrarenal aorta should be managed with EVAR and TEVAR.

  • Inflammatory aneurysms should be managed similarly to noninflammatory AAA and TAA; however, an endovascular approach may be preferred due to associated retroperitoneal fibrosis.

  • Role of endovascular stent grafts for aortic type B dissections is evolving and may play a role in patients with visceral and limb malperfusion.

  • TEVAR can be considered for aneurysmal dilatation in patients with history of type B dissections and previously repaired coarctation of the aorta.

  • Open surgical repair can be considered in those patients who are young, a good surgical risk, and have low cardiopulmonary comorbidities.

  • EVAR and TEVAR has become the preferred choice for management of AAA and TAA due to their low procedure-related morbidity and mortality.

  • The outcomes of revascularization are based on the experience of the operator and institutions with acceptable clinical outcomes.

If EVAR is planned, the following dimensions of the AAA are important:

1. Infrarenal aorta dimensions and characteristics referred as "neck"

  • Neck diameter less than 32 mm

  • Neck length of at least 10 mm

  • Neck angulation less than 60 degrees

  • <50% circumferential calcification or thrombus in the neck

2. Distal landing zone: The length of the common iliac artery (>25 mm) should allow perfusion of at least one patent hypogastric artery.

3. Distal aorta: A narrow distal aorta is the limiting factor for modular stent grafts except Endologix (Endologix, Irvine, CA, 92618).

4. Access vessels:

  • Common femoral artery (CFA) is the main access vessel.

  • Diameter of external iliac artery (EIA) determines the endograft device that can be used.

  • A minimum of 6 mm is required based on the graft chosen.

  • Previous surgery of CFA, stenosis, plaque, and calcification will determine placement of devices.

  • Tortuosity of the CFA and EIA will play a role in endograft advancement.

  • Aneurysmal dilatation of the CIA and internal iliac artery should be considered to choose the appropriate device to ensure flow into the hypogastric artery

If TEVAR is planned: The following measurements are important:

  •  The thoracic aorta proximal to the TAA should have a proximal landing zone of at least 20 mm.

  •   If the proximal landing zone is <20 mm, then carotid to subclavian artery bypass should be performed empirically.

  •   Distal landing zone should have at least 20 mm of aneurysmal free area.

  •   Access vessel should be free of, or have minimal calcification, tortuosity, stenosis, and calcification.

  •    Minimal angulation and tortuosity of thoracic and distal aorta

  •    The proximal and distal fixation zones should have <50% concentric calcification and thrombus.

Contraindications

EVAR and TEVAR: There are no real absolute contraindications

General: Patients with life expectancy less than 6 months; patients with active sepsis and infectious aneurysms

Aortic arch: Severe tortuosity, calcification, thrombus, and localized dissection may prevent the delivery of endovascular graft . These features may also impact obtaining an adequate seal and can result in endoleaks.

Vascular access: Small caliber iliac artery, tortuous iliac artery and severe stenotic vessels with calcification

Branches: The stent graft may inadvertently obscure the renal artery, left subclavian artery, or celiac artery. Ischemic and visceral malperfusion can be fatal.

Anatomic features that are outside the instructions for use (IFU) for EVAR and TEVAR devices: One example is tortuosity of the infrarenal aorta and angulation >60 degrees. Using tips and tricks, EVAR may be performed but risk of type 1 endoleak is high, as is continued expansion of the aneurysm.

Details of how the procedure is performed

Patient preparation

  • A complete history and physical examination is performed to evaluate patient status and comorbidities. A detailed history of patient and family history of anesthesia use and any intolerance is vital.

  • History should include thorough evaluation of contrast allergy and previous manifestations.

  • History of previous groin exposures and surgeries are useful if femoral cutdown or conduit is planned.

  • Anticoagulant and antiplatelet status should be documented in the chart to avoid serious bleeding issues.

Workup

  • Basic blood work is performed to evaluate the levels of hemoglobin, white blood cell count, renal function, and coagulation profile.

  • Cardiopulmonary status evaluation with cardiac history, chest radiograph, electrocardiogram (EKG), echocardiography (ECHO), and pulmonary function status are useful.

  • At our center (total number of EVAR and TEVAR performed: 1,000), rarely is a preoperative stress test performed prior to stent graft placement.

Procedure room

  • The procedure is performed preferably in a sterile hybrid lab with overhead surgical lights, adequate airflow, and air exchange.

  • The lab should have optimal digital subtraction angiography, large panel image intensifier, endovascular equipment, and the ability to perform intravascular ultrasound (IVUS).

  • The room should be large enough to accommodate surgical and anesthesia personnel with their equipment.

  • All sterile precautions of operating room is followed to minimize sepsis.

  • All personnel involved should follow a thorough scrubbing technique and don operative room wear.

  • Invasive monitoring during the procedures is essential with arterial line and patients with low ejection fraction may need right heart monitoring.

Preoperative assessment: Imaging and evaluation

  • Contrasted computed tomographic scan (CT scan) using fine cuts (1.5 to 3 mm) is the preferred imaging modality for preoperative evaluation of EVAR and TEVAR.

  • In patients with compromised renal function, a CT scan without a contrast agent maybe used.

  • CT scan without contrast cannot delineate crucial anatomic information such as a thrombus, patent inferior mesenteric artery, and occlusive disease of the iliac artery.

  • Adjuvant use of IVUS and duplex ultrasound during the endovascular stent graft implant may be of benefit in patients with renal insufficiency.

Imaging review

CT scan evaluation for EVAR: The following features are important:

  • Length of the infrarenal portion of aorta to the begining of the aneurysm (neck length)

  • Angulation of the neck and the aneurysm itself

  • Diameter of the neck at different levels, widest portion of the aneurysm, iliofemoral vessels

  • Presence of accessory renal artery

  • Presence of a thrombus and calcification in the neck and iliofemoral vessels

  • Tortuosity and stenosis severity of the iliofemoral vessels

CT scan evaluation for TEVAR:

  • Diameter of the proximal and distal landing zones free of aneurysmal disease

  • Calcification and thrombus at the landing zones

  • Tortuosity and calcification of the thoraco-abdominal aorta

  • Diameter of the iliofemoral vessels and calcification

  • Tortuosity and stenosis severity of the iliofemoral vessels

Preoperative precautions

  • If patients have elevated serum creatinine >2.0 mg/dl or eGFR <45 ml/min, such patients are usually admitted overnight for IV saline hydration and consultation with nephrology to prevent contrast-induced nephropathy (CIN).

  • At least two units of packed red blood cells are kept on standby as a safety precaution.

  • Anticoagulation is held at least 48 to 72 hours preoperatively and bridging therapy with intravenous heparin or subcutaneous low molecular weight heparin is planned. The bridging therapy is held on the day of procedure and coagulation profile is repeated.

  • Antiplatelet therapy, including dual therapy with ASA and thienopyridines or P2Y12 inhibitors, can be safely continued without increased risk of bleeding.

  • Continuation of aspirin, beta blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and statins are recommended.

Anesthesia

  • Patient is evaluated by the anesthesia team for suitability to receive general anesthetic.

  • Short-term intubation and general anesthesia is preferred; however, based on the comorbidities, monitored anesthesia care will also suffice.

  • Use of spinal anesthetic is a good option for EVAR based on the expertise of the anesthesia team.

  • Rarely, if patient has very poor cardiopulmonary reserve, we have performed EVAR and TEVAR with local anesthesia and conscious sedation.

  • In patients with previous AAA repair and needing TEVAR for TAA, spinal drainage may reduce chances of paraplegia.

  • Spinal drainage is best performed preprocedure, prior to anticoagulation.

Procedural steps: EVAR

  • Patient is placed supine on the hybrid endovascular table under general anesthesia.

  • Ipsilateral CFA cutdown or bilateral pre-close are placed after arterial access with a micro puncture needle. The most common pre-close sutures used are Perclose (Abbott Laboratories, Abbott Park, IL).

  • Combined use of fluoroscopy and duplex ultrasound to access the femoral arteries is the preferred method in our lab.

  • The main body of the device for AAA is chosen based on the tortuosity, vessel diameter, and calcification to accommodate large bore sheaths.

  • A marker pigtail catheter is advanced over a 0.035-inch wire from the ipsilateral access to obtain complete imaging of the AAA from renal arteries to the bilateral CFA.

  • The length of the ipsilateral main body of the graft should be less than the ipsilateral hypogastric artery unless coil embolization of the hypogastric artery is planned.

  • The pigtail catheter is removed from the ipsilateral side and advanced from the contralateral CFA and the side holes of the pigtail catheter is placed just above the renal artery.

  • The main body of the device is advanced from the ipsilateral CFA over a very stiff wire placed in the distal ascending aorta.

  • Heparin or direct thrombin inhibitors are given for anticoagulation as the main body of the stent graft crosses the iliofemoral vessels.

  • A limited high magnification angiogram is obtained to show the perirenal area. This angiogram identifies the bilateral renal arteries, and a marker is placed on the screen at the level of the lowest renal artery.

  • The main body of the stent graft is then deployed slowly ,just below the lowest renal artery until the contralateral limb opens.

  • The contralateral limb is cannulated using a support catheter and 0.035-inch angled glide wire. The successful crossing of the contralateral limb is confirmed by rotating the pigtail catheter inside the proximal stent graft.

  • The marker pigtail is left in situ and a limited hand injection is performed from the contralateral CFA to identify and mark the hypogastric artery.

  • The contralateral limb is chosen based on the length from the flow divider to the hypogastric artery.

  • The contralateral limb of the graft is advanced over a stiff 0.035-inch wire, with adequate overlap in the proximal segment.

  • The proximal and distal attachment zones and the overlapping segments are carefully balloon dilated, using an aortic molding balloon.

  • A final angiogram is obtained to ensure exclusion of the AAA, good seal, presence or absence of endoleak, vessel occlusion or dissection, inadvertent coverage of renal artery or the hypogastric artery, and a good distal runoff.

  • Distal pulses are checked manually or by Doppler to ensure there is no flow limiting embolization

  • The bilateral femoral access management is performed by closure of cutdown or approximation of the Perclose sutures.

The above steps are used for the majority of stent grafts, except for Endologix (Irvine, CA).

  • Endologix uses 17 Fr sheath on the ipsilateral main body side and a 9 Fr sheath on the contralateral side.

  • The contralateral access is achieved by the snare technique and then the contralateral limb is pulled down.

  • The main body with suprarenal fixation is deployed by using a second piece of the graft in an overlapping fashion inside the main body.

Procedural steps: TEVAR

Steps

1 to 4 described above for EVAR are the same. At our center, TEVAR in females, long segment thoracic stent graft patients, and those with previous AAA repair are recommended for empirical spinal drainage.

5. In TEVAR, the contralateral side is used only for the pigtail catheter to perform imaging, hence a 5 French sheath should suffice. Another alternative is to place a pigtail in the ascending aorta from the radial or brachial artery access.

6. A 5 or 6 Fr venous sheath is left in situ and a pacemaker is empirically placed if right ventricular pacing is required during the stent graft deployment.

7. The pigtail imaging is performed with steep angulation of the image intensifier to obtain an arch angiogram to demonstrate the origin of the left subclavian artery.

8. A very stiff 0.035-inch wire is advanced over a support catheter and the curved wire tip is placed in the proximal portion of the ascending aorta.

9. An angiogram from the pigtail marker catheter will demonstrate the proximal and distal landing zones and the aneurysm.

10. The main body of the device is chosen after calculating the length of the device from proximal fixation (20 mm of normal aorta proximal to the aneurysm) zone to 20 mm of landing zone distal to the aneurysm.

11. The main body is advanced from the ipsilateral side over a very stiff 0.035-inch wire. As the sheath is advanced beyond the iliofemoral vessels, intravenous anticoagulation is given.

12. The tip of the main body is placed at least 5 cm beyond the origin of the aneurysm and an angiogram of the aneurysm is performed with the pigtail that has been placed via the contralateral femoral artery.

13. The crucial step in accurate deployment of TEVAR is proper positioning of the graft material and avoiding wind socking due to the systolic force of the myocardial contraction. At our center, we recommend right ventricular pacing to decrease the movement of the graft against the cardiac contractility. The systolic blood pressure (BP) is also lowered to 90 mm of Hg. The pacing is terminated within 30 seconds as soon as the graft is deployed.

14. The pigtail catheter that is trapped behind the stent graft is withdrawn into the distal aorta and the wire is reintroduced into the graft; the tip is placed in the proximal portion of the ascending aorta.

15. A large caliber balloon is used to mold the graft at the proximal and distal landing zones.

16. A final angiogram is obtained to check for exclusion of the aneurysm, endoleaks, and inadvertent coverage of the left subclavian artery or the celiac artery.

17. Vascular access management is performed with approximation of the Perclose sutures or primary closure of the cutdown.

Aftercare: EVAR and TEVAR

  • Patient from the hybrid lab is observed in the recovery room and extubated within a few hours in most cases

  • Patient is monitored in surgical intensive care unit or step down for the next 24 to 48 hours in most elective cases. Ruptured aneurysms and infected pseudoaneurysms undergoing EVAR/TEVAR may need a longer hospital stay.

  • The cutdown sites are checked for hematoma, pseudoaneurysm, and bleeding prior to discharge.

  • The distal pulses and feet should be examined, as late distal embolization can occur.

  • Postimplant rise in body temperature and mild white cell count elevation (postimplant syndrome) is common and should subside without any further intervention.

  • At the time of discharge, we address the risk factor reduction for atherosclerosis. Patients should be discharged on aspirin, (angiotensin-converting enzyme (ACE) inhibitors or angiotension receptor blockers (ARB), statins, and tobacco cessation counseling.

  • Family counseling to screen for aneurysm in first degree relatives especially males is recommended.

  • In patients with TEVAR, close monitoring of neurologic status for paraplegia is important. Maintaining a mean pressure of 70 to 80 mm Hg by use of volume infusion and ionotropes can be beneficial.

  • Patients with EVAR and TEVAR are followed in the clinic at one week for groin check followed by CT scan at 1 month, 6 months, and yearly thereafter.

  • CT scan on follow up should be the same 1.5- to 3-mm cuts, preferably with contrast to look for exclusion of aneurysms, endoleaks, graft migration, enlargement of the graft, pseudoaneurysm, vessel dissection, thrombosis, and kinks in the graft limbs. CT scan on follow up also should be evaluated for development of new aneurysms in iliofemoral vessels.

Interpretation of results

  • On follow-up of EVAR and TEVAR, patients should remain asymptomatic and a follow-up CT scan should show stabilization of the aneurysm size or gradual shrinkage of size.

Performance characteristics of the procedure (applies only to diagnostic procedures)

Advantages: (compared with open repair)

  • Safe, easy to perform; midterm results are durable.

  • Lower morbidity and mortality

  • Shorter intensive care unit stay, hospital stay, rapid recovery, and less blood loss

  • High risk and inoperable patients can be treated safely and effectively.

  • Minimal discomfort for the patient and early ambulation

  • Multidisciplinary team approach will increase favorable patient outcomes and satisfaction.

Disadvantages:(compared with open repair)

  • Learning curve exists for the novice operator especially to handle endovascular complications, such as iliofemoral artery perforation or rupture.

  • Long-term data (>20 years) for stent grafts is not available.

  • The aneurysm can continue to grow despite percutaneous management of endoleaks and additional placement of cuffs and extenders. Such aneurysms will require a conversion to open repair and carry a high mortality.

  • Higher rate of secondary reintervention for endoleaks, graft migration ,and continued aneurysm growth.

  • The cost of the endograft, follow-up with CT scan, and reintervention can be substantial in developing countries.

  • Multiple CT scans performed during the life of patient and the contrast used during follow up may pose risk of radiation and contrast-induced nephropathy.

Outcomes (applies only to therapeutic procedures)

  • Benefits of EVAR and TEVAR

  • Easy to perform, safe, and good short-term and midterm results

  • Early hospital discharge and increased patient safety

  • Low morbidity, mortality, and low need for blood transfusion

  • Increased patient satisfaction

  • High-risk patients and inoperable patients can be treated safely and effectively

Success rate

  • Procedural: 95%

  • Failure rate requiring open conversion: <2%

  • Reintervention rates: At 1 year, 10% and up to 20% at 5 years

Alternative and/or additional procedures to consider

Alternative diagnostic information

  • As an alternative option to CT scan, magnetic resonance angiogram can provide the information regarding aneurysm size, location of renal artery, neck length, status of iliofemoral vessels, and thrombi.

  • Digital subtraction angiogram with intravascular ultrasound is very accurate to measure the aneurysm and anatomic features that are required for stent graft placement.

  • Follow-up of stent grafts with ultrasound performed by experienced technicians and interpretation by vascular specialists can replace a CT scan.

  • If additional information, such as iliofemoral vessel stenosis severity, degree of calcification, and location of a thrombus is unknown, an on table angiogram is performed and recannulation of occluded iliofemoral vessels followed by stent graft placement can be performed.

  • If the infrarenal aneurysm neck is <10 mm, several alternatives are available, such as fenestration of renal and visceral vessels, use of chimney or snorkeling technique, and hybrid debranching of the renal vessels followed by stent graft placement across the native visceral artery.

  • Similar graft modifications to exclude subclavian artery and celiac artery can be performed for TAVER.

  • Hybrid procedures such as conversion of AAA device to a unilimb device using a converter and then a fem-fem bypass graft can treat an occluded ilio femoral artery.

  • An empiric left carotid to subclavian artery bypass graft can assist in performing TEVAR for TAA close to the left subclavian artery.

Complications and their management

Morbidity and Mortality

  • The 30-day morbidity and mortality for EVAR is <2% and TEVAR should be <4%

Major complications: Most complications can be anticipated; thorough knowledge of possible complications, tips, and tricks is quintessential; appropriate imaging, equipment, multidisciplinary approach to case planning, especially with a vascular surgeon, is pivotal.

Death: Usually from inadvertent aneurysm puncture, iliofemoral vessel, or aorta perforation

Perforation: Iliofemoral vessels are the most common anatomic site for perforation due to small caliber vessel, calcification, and tortuosity: Appropriate preop evaluation can aid in planning to prevent this catastrophic complication.

  • Predilatation and stenting, especially with covered stents can prevent such perforation.

  • Use of dilators to predilate is also helpful and aids in predicting the ability of the stent graft to traverse the iliofemoral vessels.

  • Use of ilio aorta conduit (placed by vascular surgeon) can avoid traversing severely diseased vessels.

  • Bailout equipment should be kept handy, anticipating a perforation or rupture.

  • The bailout equipment includes: large caliber balloons to occlude aorta diameter up to 40 mm, large bore sheaths, 0.035-inch angled glide wire, stiff wires, covered stents both self-expanding and balloon expandable and extra pieces of stent graft limbs.

  • Large vascular plugs, coils, and glue are some of the ancillary equipment the labs should have for bail out purposes

Endoleaks

Type 1

  • This occurs due to imperfect sealing of the endograft at the proximal and distal attachment sites.

  • The antegrade blood flow at systemic pressure leads to enlargement of the sac and consequential risk of rupture.

  • There is no role for conservative management of type 1 endoleaks.

  • Such leaks should be identified and treated at the time of implantation.

Management

  • The distal leak will need an additional size-appropriate extension limb to obtain adequate seal.

  • The proximal leak is usually due to undersizing or oversizing of the graft in relation to the neck of the aorta and tortuosity or reverse taper of the neck.

  • The proximal type 1 leak will need additional balloon inflation or more frequently, an additional appropriate-size cuff

Use of a balloon mounted Palmaz (Cordis Corp., Miami Lakes, FL) stent is very helpful to provide adequate seal in persistent leaks

Type 2

  • This results from retrograde perfusion of the sac from patent lumbar artery, collateral communication between SMA and IMA and IMA also.

  • Despite up to 20% of endograft showing a type 2 leak, majority of these type 2 leaks (up to 80%) will spontaneously resolve as blood flow to the aneurysm reduces and the aneurysmal sac regresses.

Management

  • Selective catheterization of the collateral channels from the internal iliac artery to lumbar arteries and coil embolization

  • Placement of coils or glue behind the graft into the aneurysm by catheter or direct puncture of the aneurysm sac under fluoroscopy or CT guidance

  • The SMA to IMA collateral can be traversed with microcatheters and coil embolization of the IMA.

  • Direct transgraft puncture with a laser catheter followed by glue placement or coils in the aneurysm sac

  • Rare instances where the aneurysm has grown significantly may need realignment of the aneurysm with a new stent graft.

Type 3

  • These are high pressure leaks and should be addressed prior to patient leaving the lab.

  • These leaks result from tear in the fabric or modular separation of the grafts.

  • Inadequate sealing or ineffective seal at the end of the graft. Kinks in the stent graft limbs can lead to separation of the modular parts.

Management

  • May need realignment with a new graft to treat a graft material tear.

  • Additional limbs of the graft or stents to treat modular separation.

  • Use of balloon expandable or self-expanding stents in the endograft limbs to treat kinks.

Type 4

  • Here temporary oozing of blood due to porosity of the graft can occur.

  • This was noted in the older material of the stent graft and newer stent grafts have overcome such leaks.

Endotension

  • This is a term used to describe an aneurysm sac pressurization in the absence of an endoleak.

  • The precise etiology of endotension is unknown.

  • If the sac continues to grow without any evidence of endoleaks, endotension can be demonstrated by translumbar puncture and direct aneurysm sac pressure measurement

  • Realignment of the graft or explant and open repair maybe needed.

  • The recent advances and advent of newer graft and graft material has minimized the occurrence of endotension.

Other complications

1. Buttock claudication, erectile dysfunction, and gluteal ischemia

This can occur in patients who undergo hypogastric artery coil embolization and placement of a stent graft to treat AAA with iliac aneurysms or patients with short segment CIA (<25 mm).

  • Cilostozol can improve claudication along with a supervised exercise program.

  • Erectile dysfunction can be managed with urologic consultation and use of phosphodiesterase 5 inhibitors.

  • Significant symptoms may need hypogastric artery to external iliac artery bypass graft surgery.

2. Intestinal ischemia/ischemic colitis

  • In patients who undergo EVAR, if celiac artery and SMA have hemodynamically significant stenosis, EVAR will cover the inferior mesenteric artery.

  • In such patients, intestinal ischemia is a dreaded complication.

  • Such a complication is noted in 2% of elective cases.

Management

  • Empirical or postimplant revascularization of celiac and mesenteric artery stenosis.

3. Contrast induced nephropathy

  • Occurs in patients with preexisting renal insufficiency, diabetes mellitus, and congestive heart failure.

  • Adequate prehydration, discontinuation of nonsteroidal antiinflammatory drugs and diuretics can reduce the chances of CIN.

  • Minimizing the amount of contrast used can reduce the occurrence of CIN.

Management Anaphylaxis

  • If patient has true allergy to contrast, anaphylaxis can have various manifestations—from rash, to hypotension, bronchospasm, and death.

Management

  • An empirical use of steroids and antihistamines can prevent such anaphylaxis.

  • If anaphylaxis is noted during or immediately after the procedure, use of epinephrine in appropriate doses can be life saving.

TEVAR Complications

  • The endoleak management is similar to EVAR; however, may need carotid to subclavian artery bypass or bypass of mesenteric vessels to provide adequate landing zone

  • Graft migration may need realignment with new graft or placement of extension pieces.

Spinal paralysis

  • Paraplegia can occur in 3% to 4% of cases.

  • Empirical spinal drainage and maintaining a mean pressure 70 to 90 mm Hg is useful.

Stroke

  • This can occur in up to 5% of TEVAR cases.

  • Careful manipulation of the wires, large bore devices across the diseased aortic arch.

  • Preemptive subclavian to carotid bypass can reduce the stroke incidence.

What’s the evidence?

Greenhalgh, RM, Brown, LC, Kwong, GP, Powell, JT, Thompson, SG. "EVAR trial participants. Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomised controlled trial". Lancet. vol. 364. 2004. pp. 843-8.

Prinssen, M, Verhoeven, EL, Buth, J. "Dutch Randomised Endovascular Aneurysm Management (DREAM) trial group". N Engl J Med. vol. 351. 2004. pp. 1607-18.

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