Abdominal Aortic Aneurysms: An Update on Open and Endovascular Repair Introduction and Overview
APACVS Miami 2019
Jonathan S. Deitch MD, FACS Chief, Division of Vascular & Endovascular Surgery Staten Island University Hospital Northwell Health System WHAT DO THESE PEOPLE HAVE IN COMMON?
Albert Einstein George C. Scott Lucille Ball One in nine males will die of a ruptured aneurysm Why Repair Them?
Prevent Rupture Abdominal Aortic Aneurysm ANEURYSMS
Aneurysm = increase in size > 50% of normal diameter Ï True aneurysm: all three layers of the vessel wall Ï Pseudoaneurysm: focal defect in the artery with collection of blood contained by adventitia and periarterial tissue Normal aortic diameter: 1.0 – 2.4 cm Ï Aneurysmal aortic diameter: 3 cm Ï Size for repair: 5.5 cm Normal iliac diameter: 0.6 – 1.2 cm Ï Size for repair: 3.5-4.0 cm ANEURYSMS
Morphology Ï Saccular: focal outpouching of the arterial wall Ï Fusiform: smooth, circumferential dilation Etiology Ï Degenerative Ï Traumatic Ï Infectious (mycotic) Syphilis, AIDS, Candida Ï Inflammatory Ï Autoimmune or connective tissue disease Marfan syndrome, familial thoracic aortic aneurysm, vascular-type Ehlers-Danlos Ï Note: aneurysms ≠ dissections, but you can have aneurysmal degeneration as a complication of a dissection AORTIC ANEURYSMS
Incidence is somewhere from 3-10% Ï Approximately 40,000 operations annually in the US Risk factors: development Ï Tobacco, DL, HTN, males, family hx Risk factors: expansion Ï Tobacco, advanced age, severe cardiac disease, previous stroke, cardiac or renal transplantation Risk factors: rupture Ï Tobacco, females, larger initial diameter at diagnosis, higher mean BP, cardiac or renal transplantation, diminished FEV1/COPD AORTIC ANEURYSMS
Familial risk factors Ï Siblings and children of patients diagnosed with AAA have 8- 11 x the standard risk for AAA development Ï Particularly true of the abdominal and thoracic aorta; risk does not seem to be true for peripheral aneurysms Ï 7% of 1st-degree relatives of patients with AAA are found to have aneurysmal disease when screened AORTIC ANEURYSMS
Suprarenal Ï Extend above the renal arteries Ï By definition will require reimplantation of at least one renal artery during repair Juxtarenal Ï Do not involve the renal arteries, but require clamping above the renals due to proximity Infrarenal Ï Most common type Ï Below the renal arteries Abdominal Aortic Aneurysms What size warrants intervention? Does size matter?
What is the risk of aneurysm rupture based on size?
In other words, What is the natural history of abdominal aortic aneurysms? Does size matter? 5 cm?
How about rate of growth ? Interpreting Studies
1. Treat the individual, not the statistic.
2. Size is not all that matters.
3. Outcomes matter. Laplace’s Law
T = PR Natural history of Abdominal Aortic Aneurysms
Estes/Wright (1950)
33% - 40% mortality at 1 year of diagnosed AAA
81% - 96% mortality at 5 years
63% died from aneurysm rupture Szilagyi, et al (1966)
Small (<6cm) vs. Large (>6cm) Untreated AAA
125
100
75
Small (<6cm) untreated 50 Survival Survival Rate (%)
Large (>6cm) untreated 25
0 1 2 3 4 5 6 7 8 9 10 11 12 Survival in Years Szilagyi, et al (1966)
Surgical vs. Untreated Small (<6cm) AAA 125
100 Small (<6cm), surgical
75
50 Survival Survival Rate(%) Small (<6cm) untreated 25
0 1 2 3 4 5 6 7 8 9 10 11 12 Length of Survival in Years Conclusions from Historical Data
5 Year risk of rupture based on size
< 4 cm 2%
4cm - 5 cm 3% - 12%
> 5cm 25% - 41% TREATMENT
But what about… Ï 4.0 – 5.4 cm UK Small Aneurysm Trial + Aneurysm Detection and Management Trial (ADAM) No difference in long-term survival in further surveillance (to >5.4cm) vs surgery Surgery = 30-day operative mortality (leading to an early disadvantage in survival) Non-significant benefit trends: earlier surgery for younger patients with larger aneurysms Ï May have benefit for repair in younger, healthier, or female patients with aneurysm 5 – 5.4cm AORTIC ANEURYSMS
AAA Diameter %/yr Rupture Risk < 4 0 (borderline normal aorta) 4-5 0.5 – 5 5-6 3 – 15 6-7 10 – 20 7-8 20 – 40 > 8 30 – 50
= Roughly 10% increase in risk of rupture per year with each additional cm increase in size TREATMENT
So when can we operate? Fix it! Ï Aneurysm > 5.5 cm Ï Growth rate > 0.5 cm in 6 mos OR > 1 cm in 1 year Ï Generally for saccular morphology ILIAC ANEURYSMS
Typically occur in conjunction with aortic aneurysms 11% of patients have iliac aneurysms in isolation…but 25- 40% of abdominal aortic aneurysms have associated iliac aneurysms
Aortic Iliac Aneurysms Aneurysms CURRENT MEDICAL CONCERNS
Metformin may reduce the rate of growth of AAAs (shown in VA population)
Flouroquinolones (Levoquin and Cipro Abx) May accelerate growth rate and is associated with increased rupture rate of AAAs in 4 studies How do we decrease mortality and improve outcomes with AAA?
Early Diagnosis of AAA
Surveillance & Intervention Medical Treatment (Open, Endovascular) How do we diagnose AAA?
Incidental Finding Physical Exam Ultrasound DIAGNOSIS
Physical examination Ï Positive predictive value formula: BMI < 24 + Aorta > 8 cm + previous diagnostic CTA confirming aortic aneurysm = 100% likelihood that aneurysm may be appreciated on physical exam Ï In actuality, 30-40% are found on physical exam When > 5 cm, detected in 76% When < 4 cm, detected in 29% Ultrasound Ï Sensitivity/Specificity for detection 90-100% Ï Poor characterization of overall morphology CTA Ï Imaging of choice Ï Cheaper than MRA SCREENING
Who needs to be screened?
Society for Vascular Surgery (2009 Practice Guidelines) Ï One-time screening
All men > 65 years All men > 55 years with family hx
All women > 65 years with family hx or smoking hx
US Preventive Services Task Force Ï One-time screening
Men 65-75 years with smoking hx SCREENING
Medicare (from the Screening Abdominal Aortic Aneurysms Very Efficiently Act – SAAAVE Act) Ï Initial Welcome-to-Medicare exam
Men with smoking hx
Men or women with family hx
World Health Organization Ï Men > 65 years with ultrasound, provided necessary resources are in place
American Heart Association + American College of Cardiology; American College of Preventive Medicine; Canadian Society for Vascular Surgery; European Society for Vascular Surgery SURVEILLANCE
How frequently should we reimage? Ï 2.6 – 2.9 cm: follow up in 5 years Ï 3 – 3.4 cm: follow up in 3 years Ï 3.5 – 4.0 cm: follow up in 1 year Ï 4.1-5.0 cm: follow up in 6 months PRE-OP PLANNING
CT imaging to evaluate anatomic variations Ï Retroaortic renal vein Ï Bifid vena cava Ï Horseshoe kidney Ï Accessory renal arteries Ï Vascular calcifications in clamp zones Ï Patency of branch vessels (IMA, lumbars, iliac branches) PRE-OP PLANNING
Renal insufficiency Ï Open and endovascular approaches can both lead to a decrease in renal function with existing disease Ï 20-38% of patients with AAA have renovascular occlusive disease Ï If disease is clinically significant, simultaneous repair is indicated Intra-op renal protection Ï Hydration Ï Avoid hypotension Ï Discontinue ACE-I and ARBs pre-op, but resume post-op Ï +/- utility of mannitol, Vit C, Vit E, N-acetylcysteine, allopurinol, fenoldopam Suprarenal clamping Ï Preclamp administration of Lasix + mannitol Ï Use cold saline perfusion for the kidneys Ï Selective use of fenoldopam Endovascular repairs Ï IV hydration Ï Carbon dioxide imaging OPEN VS. EVAR?
EVAR offers shorter stay and higher likelihood of return home (rather than STR or SNF) One study of functional status post-AAA repair found: Ï 30% of patients felt like they “never completely recovered” Ï 18% of patients would take a risk of rupture and not undergo the procedure again, given the choice Quality of Life metrics are essentially equivalent by 12 months
The relative benefits of EVAR, compared to open, are dependent on the operative mortality rate “Open repair should be offered to suitable patients with non ruptured AAAs preferentially to EVAR because of associated long term costs and complications associated with EVAR compared to Open repair” OPEN VS. EVAR?
Open Repair EVAR
Pros Pros Ï Very low rupture rate (0.5% Ï Lower 30-day mortality at 4 yrs) (1.2%) Ï Very low reintervention rate Ï Increased benefit with (1.7%) increased age of patient Cons Cons Ï More likelihood of rupture Ï Higher 30-day mortality (1.8% at 4 yrs) (4.8%) Ï Higher reintervention rate Ï Higher rate of surgery or (9%) hospitalizations for laparotomy complications, hernia, or SBO OPEN REPAIR OPEN REPAIR
Transperitoneal Retroperitoneal Advantages •Most rapid •Avoids hostile abdomen •Greatest flexibility •Facilitates exposure of •Can evaluate for intra-abd juxta/pararenal AAA pathology •Decreased ileus •Easier for obese patients •Acceptable for inflammatory AAA or in patients with horseshoe kidney Disadvantages •Longer ileus •Poor access to right renal •Greater fluid losses and right iliac arteries •Difficulty with •Cannot eval for intra-abd exposure/control for pathology juxta/pararenal AAA •Chronic pain or flank laxity •Ventral hernia OPEN REPAIR
Transperitoneal Ï Good for infrarenal aneurysms Ï Rapid exposure Ï Excellent iliac and renal vessel access Ï May require ligation/division of left renal vein or the gonadal + lumbar + adrenal vein tributaries to provide suprarenal exposure, if needed OPEN REPAIR
Midline laparotomy incision Ï Prep from nipples to thighs Ï Plan incision from the xiphoid to the pubis Ï If femoral arterial extension is needed, do the femoral dissection before laparotomy Ï If done for rupture: prep and drape before intubation, make the incision simultaneously with anesthesia induction OPEN REPAIR
For supraceliac clamping Ï Divide triangular ligament, mobilize left lobe of liver Ï Reflect esophagus to the left (easier if NGT is in place) Ï Divide the crura of the diaphragm Ï Mobilize the aorta for supraceliac clamping, or move the clamp distally to the supra/infrarenal position as appropriate OPEN REPAIR OPEN REPAIR
Infrarenal exposure Ï Mobilize the duodenum distal to the ligament of Treitz to the right Ï Open the retroperitoneum to the level of the iliac bifurcation Ï Mobilize the left renal vein as needed to facilitate exposure of the aneurysm neck OPEN REPAIR OPEN REPAIR
Iliac exposure Ï Dissect in the avascular anterior plane Ï Ureter crosses at the iliac bifurcation Ï Pelvic sympathetic nerves cross the aortic bifurcation and proximal left common iliac Ï Can typically avoid extensive dissection over the bifurcation and proximal iliacs Ï Clamp distally at the mid/distal CIA, or in the EIA + IIA Ï Iliac control: clamps, vessel loops, Rumel tourniquets, or balloon occlusion Ï Avoid (catastrophic) venous injury OPEN REPAIR OPEN REPAIR
Retroperitoneal Ï May reduce physiologic stress Ï Reduce pulmonary complications Ï Reduce post-op ileus Greater access to the visceral aorta and can be extended into the thorax RUPTURE
Pre-op Ï Permissive hypotension Ï SBP 50-80 mmHg “adequate” if patient is conscious Ï Avoid aggressive volume resuscitation Ï CTA when possible In the OR Ï Endovascular repair is possible under local Ï If open repair, prep and drape before inducing Ï Obtain supraceliac clamping first, then ask questions Ï Endovascular balloon occlusion is an option COMPLICATIONS
After open repair Ï Cardiac ischemia / MI
Accounts for 50% of deaths related to aortic reconstruction Ï Renal insufficiency
Embolization from clamping, hypovolemia, prolonged ischemia, intrinsic renal artery disease, perioperative hypoperfusion Ï Pulmonary insufficiency
Most prevalent with proximal/paravisceral aortic repairs Ï Colonic ischemia Ï Anastomotic aneurysms: up to 20% at 15 years
More common in femoral anastomosis
Sterile or infection-related Ï Abdominal wall hernias: 10-33% Ï Graft limb thrombosis: 5-10%, associated with younger, female, or extra-anatomic bypasses COMPLICATIONS
After repair for rupture Ï Colon ischemia, renal failure, spinal infarction, pancreatic injury Ï Abdominal compartment syndrome (can happen even after endovascular repair) Aortic Endografting
• Less invasive alternative to open surgery • Should be considered in all patients who present with AAA • Used selectively for those patients with appropriate anatomy • Caution its use in “young” patients PEVAR PEVAR Endovascular Repair Type I Endoleak Type I Endoleak
Early Late
Endoleak Final Angio
Early Late Type II Endoleak Embolization of Type II Endoleak
Leak Micro Catheter
Ilio-lumbar
Internal Iliac Type III Endoleak Type IV Endoleak Monitoring
Contrast CT Scan at:
30 days postop 12 months and annually thereafter
Duplex Ultrasound at: 6 month intervals (can be used more frequently if sac is shrinking and no evidence of endoleak) Is mortality and morbidity diminished with Endografts?
Probably YES
Probably NO Is quality of life improved in patients receiving endografts? Open repair POD #1 AORTIC ENDOGRAFT
POD #1 Preoperative CT Scan Postoperative Studies Postoperative Angios Abdominal Aortic Aneurysms Endovascular Repair: Open Aneurysm Repair
FOREVER Endograft Repair
Long Term Monitoring Endoleak Endovascular AAA Repair Advantages
• Patient discomfort and disability is dramatically less • Morbidity and mortality may be diminished, particularly in elderly, more infirm patients Durability?
• Serial follow-up with CT • Over 2 years, 10-15% of patients will require reintervention for endoleak • Reinterventions are usually catheter-based or through the groin • Long term outcome (10-15 years) is unknown What percentage of patients are candidates for endografts?
Perfect Limited 20% Old Anatomy Experience
Young Imperfect Extensive 90% Anatomy Experience NEW INNOVATIONS for COMPLEX AAA ENDOANCHORS Zenith Fenestrated Aortic Graft Snorkel technique SNORKEL TECHNIQUES Who should have an endograft? Patients with suitable anatomy!
Health Age Endograft?
Infirm Any YES Good > 75 YES Good < 65 NO Good 65 - 75 ? Thank you