1.  Endovascular Repair of AAA and TAA A. Berezin, MD, Ph.D 2/14/2007

3. Endovascular Repair of AAA

4. Endovascular Repair of AAA Current estimates are that more than 20000 EVAR procedures take place each yeas in the USA, which represents ~36% of all AAA repair. The estimate is that >12% of all procedures in Europe are with EVAR, and expected annual growth is ~15% at this time. The endovascular repair of AAA and TAA has became a viable alternative to open repair and is often the approach of choice for high risk patients because of its: minimal incisions, shorter operating time reduced blood loss.

5. Endovascular Repair of AAA A ruptured AAA has a mortality rate approaching 90%.When an AAA is repair electively, the mortality drops to less than 5%.AAA affects 4% 7% of adult over the age of 65 years, with a far greater prevalence in male than in female, this problem will encounter more frequently as population ages.

6. Indications for AAA treatment Patients with symptomatic aneurysms should be offer repair, after careful consideration of comorbidities, even if the aneurysm is not of usual elective operation size. Patients with the aneurysm increases in size by 1 cm per year.

7. Indications for AAA treatment Most asymptomatic AAA’s are discovered by accident often on imaging examination for other complains. For the patients with asymptomatic AAA’s there is guidelines to help plan further surveillance or operative repair. The size of the AAA is one factor, and the operative approach is another. In general, the clinical recommendation remains to offer treatment for AAA between 5 and 5.5 cm, depending on the results of clinical trials.

8. Clinical and Anatomical Selection Factors Patient selection has emerged as the most important factor related to successful EVAR. 3D reconstruction CT scan or angiography with a calibrated catheter necessary for assessment for EVAR eligibility. Proximal neck: diameter, length, angel, presence or absence of thrombosis Distal lending zone: diameter and length Iliac arteries: presence of aneurysm or occlusive disease Access arteries: diameter, presense of occlusive disease Up to 37% of all patients may NOT be suitable candidate for EVAR of their infrarenal AAA.

9. Evaluation for EVAR Contraindications for EVAR Short of proximal neck Thrombus present in proximal landing zone Conical proximal neck Greater than 120º angulations of the proximal neck Critical inferior mesenteric artery Significant iliac occlusion Torture of iliac vessels

10. EVAR AAA Repair

11. Indication for EVAR AAA repair Open repair is advocated for younger, lower-risk patients. Open surgical repair of AAA has proven long-term durability. EVAR is preferred for older, high risk patients. EVAR has shown a reduction in 30-day mortality relative to that achieved with open repair ( 1.2% versus 4.6% ) EVAR follow up is now 15 years. Further study is required to determine whether there is a long-term survival advantage. Risk stratification determines survival in general and shows that both open surgery and EVAR decrease the risk of death from AAA rupture

12. EVAR complications Deployment related Failed deployment Bleeding Hematoma Lymphocel Infection Embolization Perforation Arterial rupture Dissection Device related Structural failure Implant related Endoleaks Limb occlusion/stent-graft kink Sac enlargement/proximal neck dilatation Stent migration AAA rupture Infection Buttock/leg claudication

13. EVAR complications Systemic Cardiac Pulmonary Renal insufficiency, contrast-induced neuropathy Deep vein trombosis Pulmonary embolism Coagulopathy Bowel ischemia Spinal cord ischemia

14. EVAR complications Endoleak is the most common complications, greater than 20% - 30% in some studies. An endoleak is define as persistent blood flow outside the wall of the stent into the aneurysmal sac. The endoleak exposes the weak aneurysm wall to continues flow that may lead to rupture. Any increase in the aneurysm sac warrants immediate repair.

15. Classification of Endoleaks I: Attachment site leaks Proximal end of endograft Distal end of endograft Iliac occluder ( plug ) II. Branch leaks ( without attachment side connection ) Simple or to-and-fro (from only 1 patient branch) Complex or flow-through ( with 2 or more patient branches). III. Graft defect A. Junction leak or modulator disconnect Fabric disruption ( midgraft hole ) IV. Graft wall ( fabric ) porosity ( <30 days after graft placement )

17. Intraoperative management, M.M.Mondecai,2004 The procedure is less invasive. Requires minimal anesthesia. Less likely to induce homodynamic stress. May still be associated with risks and complications of any aortic surgery such as massive sudden blood loss because of aortic rupture.

18. Monitoring during EVAR of AAA Appropriate catheters for homodynamic monitoring Large-bore intravenous catheter. Arterial catheter for continuous BP monitoring and to collect samples for ABG, Hb, clotting time. CVP line should be consider to provide central vasopressors delivery and to maintain adequate intravascular volume. PA catheter or TEE can provide more accurate assessment of cardiac function and intravascular volume in patients with poor LV function or renal failure. A Foley catheter is an additional measure of volume status.

19. General Anesthesia, M.M.Mondecai,2004 GA typically consist of a balance technique with low-dose inhalation agent and opioids. Neuromuscular blockers are typically not necessary. The case can be perform with laryngeal mask. GA provides: maintain of potency of airway allows for homodynamic manipulation accommodate for variation in duration of operation reduce the possibility of patient movement allows for control of respiration during fluoroscopy

20. General Anesthesia, M.M.Mondecai,2004 Placement intravascular lines or monitors is more easier. Supine position tolerates better during long operation. GA is: associated with more hypotensive episodes increased fluid requirement increased use of inotropic support compare to RA

21. Regional Anesthesia, M.M.Mondecai,2004 Spinal, epidural, and combined spinal-epidural techniques have been used. T 10 sensory level is needed for iliac arteries exposure provides fever homodynamic side effect. Advantages of EA: ability to titrate achieve the appropriate sensory level accommodate variation in duration of the procedure minimize hemodynamic changes shorter postoperative hospital stay

22. Regional Anesthesia, M.M.Mondecai,2004 Potential disadvantages with RA: difficulties in patient comfort while placing intravascular lines patient tolerance for supine position on the OR table need to convert to GA if procedure is converted to an open repair low risk of spinal or epidural hematoma while receiving intrapoperative Heparin

23. Local anesthesia, M.M.Mondecai,2004 Local anesthesia well tolerated for transfemoral approach: Decrease fluid requirement Decrease operating time Decrease of innotropic agent Decrease of hospital stay Patient commonly feels pain during dilatation which resolves with deflation of balloon. Persistent pain after deflation of the balloon may indicate arterial rupture with extravasation and should be investigated.

24. PVB vs GA for EVAR of AAA, J.Falkensammer et al, 2006 (Jacksonville, FL) 10 pt with AAA repair with PVB with propofol sedation ( 1 case conversion to GA due to block failure) vs 15 pt. with GA PVB (paravertebral blockade) : less hypotension less blood pressure liability less postoperative PONY PVB can be perform safely in pt. with significant comorbidities

25. RA or LA techniques, M.M.Mondecai,2004 With RA or LA preparations must be made for conversion to GA : acute aortic rupture with hypotension ( hypotension may include an allergic reaction to contrast dye and a side effect of adenosine) in the event of open procedure if further access to the ileac arteries is needed if patient is unable to tolerate supine position innotropic and vasodilatating agent should be prepared for the treatment of homodynamic instability

26. Proximal Graft Deployment, R.A.Kaplan et al, Induced hypotension during device deployment has been used successfully to assist in proximal placement and may reduce the magnitude of migration: pharmacological induction of sinoatrial and atrioventricular nodal inhibition with high dose of Adenosine induced ventricular fibrillation (by applying an alternating current to the endocardial surface through a temporary transvenous ventricular pacing lead) using Nitroglycerin or Sodium Nitroprusside

27. Postoperative care, M.M.Mondecai,2004 Recovery after uncomplicated EVAR does not routinely require the use of ICU. Analgesic requirement are minimal and can managed with small boluses of opioids or NSAID. Postinflamation syndrome related to a systemic inflammatory response to graft material can occur, manifesting with fever, leukocytosis, and increase C-reactive protein concentration. Hyperepyxia can be associated with tachycardia. The average length of stay in the hospital is minimal.

28. EUROSTAR DATA, 2006 Influence of anesthesia on outcome after endovascular AAA repair. From 7/1997 to 8/2004, 5557 pt. underwent EVAR repair in 164 centers were enrolled in the EUROSTAR registry. General anesthesia (GA-G) - 3848 pt. (69%) Regional anesthesia (RA-G) - 1399 pt. (25%) Local anesthesia (LA-G) - 310 pt. ( 6%) Multivariable logistic regression analysis was performed on early complications.

29. EUROSTAR DATA , 2006

30. EUROSTAR DATA, 2006 EUROSTAR data indicate that patients appeared to benefit when a locoregional anesthetic technique was used in EVAR. Locoregional technique should be used more often to enhance the preoperative advantage of EVAR in the treating AAA. Ultimately, a prospective randomize study is necessary to clarify the question of which method of anesthesia is suitable.

31. EVAR vs. open ruptured AAA repair, J.J. Visser, et al 2006, Netherlands, MGH

34. EVAR vs. open ruptured AAA repair, J.J. Visser, et al 2006, Netherlands, MGH

35. EVAR vs. open ruptured AAA repair, J,J, Visser, 2006 Mortality and complications rates after EVAR may be similar compared with those after open surgery in patients treated for ruptured infrarenal AAA.

36. If emergency EVAR associated with higher secondary intervention in AAA repair B.I. Orenan et al, 2006, Netherlands

37. Is emergency EVAR associated with higher secondary intervention in AAA repair ( B.I. Orenan et al, 2006) To our surprise, emergency endovascular AAA repair did not present with higher secondary intervention rate at mid-term follow- up ( 38 ± 26 month).

38. Long-term outcome after EVAR AAA: The First Decade, Brewster D.C et al, 2006, MGH 873 pt underwent EVAR since 1/1994 to 12/2005 Mean follow up was 27 month 39% of pt had 2 or more major comorbidities 19% of pt. would be categorized as unfit for open repair Device deployment was successful in 99.3% 30 day mortality was 1.8% Freedom from AAA rupture was 97.6% at 5 years and 94% at 9 years Significant risk factor for late AAA rupture included female gender and device related endoleak Aneurysm related death was avoided in 96% 87 (10%) pt. required reintervention, with 92% being catheter-based and a success rate of 84% Predictor for reintervention: first generation device and late onset endoleak

39. Long-term outcome after EVAR AAA: The First Decade, Brewster D.C et al, 2006, MGH Current generation stent graft correlated with significant improve outcome. Cumulative freedom from conversion to open repair was 93% at 5 through 9 years. Cumulative survival was 52% at 5 years. EVAR using contemporary devices is a save, effective, and durable method to prevent AAA rupture and aneurysm related death. Assuming suitable AAA anatomy, these data justify a broad application of EVAR across a wide spectrum of patients.

40. 2 year Outcomes after Conventional of EVAR of AAADREAM Trial Group, 2005 Randomized trial, multicenter comparing open repair with EVAR in 26 centers in Netherlands and 4 centers in Belgium. Open repair EVAR 178 pt 173 pt 2 y survival rate 89.6 89.7 Aneurysm related death 5.7 2.1 Survival free of complications 65.9 65.6 The perioperative survival advantage with EVAR repair as compare with open repair is not sustained after the 1-st postoperative year.

41. Cost EVAR repair, Abularrage CJ, et al. 2005

42. Cost EVAR repair, Abularrage CJ, et al. 2005

43. Endovascular TAA repair The first thoracic stent graft was deployed for TAA exclusion in 1992 Cumulative clinical experience is estimated 5000 implants worldwide has yielded short- to mid-term data that demonstrated promising results. 3 clinical trials are approval by FDA: TAG (W.L. Gore and Associates, Inc), Talent (Medtronic, Inc), TX2 (Cook, Inc). The endoprosthesis are composed of a metal skeleton (nitinol, stainless steel, Elgiloy) covered with fabric ( polyester or polytetrafluoroethylene PTFE). Graft can be deployed by a self-expanding mechanism or balloon expansion.

44. TAA repair With an incidence of 6 to 10 per 100 000 person-years TAA’a less common than AAA but remain life-threatening. With an associated mortality rate of 94%, TAA rupture is usually a fatal event. The 5 years survival rate of unoperated TAA patients approximates 13%, whereas 70% to 79% of those who undergo elective surgical intervention are alive at 5 years. The risk of rupture mandates consideration for surgical treatment in all patient who are suitable for operation.

45. Complications TAA repair Mortality for TAA surgical repair ranges from 5% to 20% in elective cases and to 50% in emergent situation. Major complications associated with surgical TAA repair include: Renal and pulmonary failure Visceral and cardiac ischemia, stroke Paraplegia Paraplegia occurring in 5% to 20% of cases versus <1% for AAA. For these reasons, a significant population of TAA patients are not candidate for open repair and have been without a treatment options until recently.

46. Endovascular TAA repair Development of stent grafting in the TA has progress more slowly 1. The hemodynamic forces of the TA are significantly more aggressive and place greater mechanical demand of thoracic endografts. The potential for devise migration, kinking, and late structural failure are important concerns. 2 .Greater flexibility is required of thoracic devices to conform to the natural curvature and to the lesions with tortuous morphology. 3. Because larger devices are necessary arterial access is more problematic. 4. TAA can often extend beyond the boundaries of the descending TA and involve more proximal or distal aorta the desired.

47. Anatomical Requirements for Repair of TAA A proximal neck at least 15 to 25 mm from the origin of the left subclavian artery. A distal neck at least 15 to 25 mm proximal to origin of the celiac artery. Adequate vascular access: absence of severe tortuosity, calcification, or atherosclerotic plaque burden involving the aortic or pelvic vasculature. The transverse diameter of the proximal and distal neck should be within the range that available devices can appropriately accommodate.

48. EVAR TAA Repair

49. Indications for Endovascular Repair Patient for TAA repair considers their overall risk profile: evidence of rapid enlargement of aneurysm, diameter > 6cm, presence of symptoms Endovascular stent grafting is currently reserved for high-surgical-risk and nonoperative patients who have suitable anatomic features. High resolution 3D rendering of the aorta, catheter based angiography remains the “gold standard” which helps to select the appropriate device diameter and length. Determination of aneurysm location in relation to the left subclavian and celiac axis is up most importance.

50. Requirements for EVAR Repair Vascular access route must be of sufficient size. Small-diameter of femoral arteries, tortuous, and excessive calcified of iliac arteries requiring more proximal retroperitoneal exposure. Severe stenosis and tortuosity of abdominal or thoracic aorta distal to the target are contraindication for endovascular repair. Treatment failure can occur. Follow up surveillance with serial CT scan at 1, 6 and 12 months is recommend to monitor changes in aneurysm morphology, identify device failure and detect endoleaks.

52. Endovascular Repair of TAA Successful device deployment is achieved in 85% to 100% of cases. Preoperative mortality ranges from 0% to 14%, falling within or below elective surgery mortality rates of 5% to 20%. Outcomes have improved over time: with accumulative technical experience use of commercially manufactured devices improved patient selection criteria

53. Endovascular Repair of TAA Collective experiences of the EUROSTAR and United Kingdom Thoracic Endograft registries: the largest series to date ( n=249) demonstrate successful rate deployment in 87% of cases 30-days mortality of 5% for elective cases paraplegia and endoleak rates of 4% FDA phase II trial data from exclusive deployment of the Gore TAG endograft in 142 TAA patients reveal similar resuils: technical success in 98% 30-days mortality of 1.5% endoleak in 8.8%

54. Complications Endoleak is less than reported for AAA endograft repair. More commonly at the proximal or distal attachment sides ( type I) represent direct communications between the aneurysm sac and aortic blood flow. Treatment options include: transcatheter coil glue embolization balloon angioplasty placement of endovascular graft extention open repair

55. Paraplegia Incidence of paraplegia is lower due to: avoidance of aortic cross-clamping avoidance prolonged iatrogenic hypotension Occurrence of paraplegia is associated with: concomitant or prior surgical AAA repair increased exclusion length because of the absence of lumbar and hypogastric collateral circulation.

56. Strategies to Manage Paraplegia Risk after EVAR Repair of TAA, AT Cheung,2005 75 pt ( male=49, female=26, age =75+/-7.4 years) Lumbar CSF drainage ( n=23) and Somatosensory EP monitoring ( n=15) were performed selectively in pt. with significant aneurysm extent or with previous AAA repair (n=17). Spinal cord ischemia occurred in 5 pt. ( 6.6% ): 2 had SSEP loss after stent deployment 4 developed delayed-onset paraplegia 2 had full recovery in response to art. pressure augmentation alone 2 had full recovery 1 had near-complete recovery in response to art. pressure augmentation and CSF drainage The incidence of permanent paraplegia or paraparesis was 2.7% (2 0f 75)

58. Risks Spinal Cord Ischemia (Chung et al, 2005) Previous AAA repair. Hypotension associated with an occult retroperitoneal bleeding. Severe atherosclerosis of the Thoracic aorta. Injury to the external iliac artery. Extend of the descending Thoracic aorta covered by graft.

59. Strategies to Manage Paraplegia Risk after EVAR Repair of TAA, AT Cheung,2005 Early detection and intervention to augment spinal cord perfusion pressure was effective for decreasing the magnitude of injury or preventing permanent paraplegia from spinal cord ischemia after EVAR of descending TAA. Routine use of motor and somatosensory evoked potential monitoring, serial neurological assessment, arterial pressure augmentation, CSF drainage may benefit patients at risk for paraplegia.

60. Stent graft vs open repair TAA, D.H.Stone et. Al, 2006, MGH

61. Stent graft vs open repair TAA, D.H.Stone et. Al, 2006, MGH Operative mortality was halved with Sten-graft, with similar late survival for both groups. Reinterventions were required at a nearly identical rate for open and Stent-graft. Spinal cord injury were similar in both groups.

62. Endovascular Repair of AAA and TAA The introduction of EVAR of aortic aneurysm has presented a unique treatment option to approximately half of the patients presenting for AAA repair. The immediate benefits of reducing early morbidity, blood loss, length of stay, and recovery have been proven. The long –term success of the EVAR is of concern because of the need for lifelong surveillance, secondary intervention, and continued risk of the aneurysmal rupture .

63. Endovascular Repair of AAA and TAA As the technology of this surgical technique continues to develop, there is hope that material and structural designs will help resolve some of these issues. Indications for endovascular stent graft replacement now extend well beyond elective AAA repair to include repair of ruptured AAA in patients with contained bleeding, TAA aneurysm, and aortic injuries caused by trauma.