Abdominal Aortic Aneurysms Diagnosis and treatment

AAA defintion Varies by age, gender, body surface area Typically diagnosed if aortic diameter is ≥ 3.0 cm* Normal aorta Aorta with an abdominal aneurysm *ACC/AHA Guidelines on PAD Circulation 2006;113:e463-465.

ACC/AHA Guidelines on PAD Circulation 2006;113:e463-465. Prevalence of AAA In the US, AAA causes almost 14 000 deaths each year and accounts for 63 000 hospital discharges Age (years) Men Women 2.9 - 4.9 cm 45-54 1.3% 0% 75-84 12.5% 5.2% ACC/AHA Guidelines on PAD Circulation 2006;113:e463-465.

Risk factors associated with AAA Older age Male sex Family hx Smoking Hypertension Dyslipidemia Atherosclerotic disease COPD ACC/AHA Guidelines on PAD Circulation 2006;113:e463-465.

Types of AAA Morphological classification Segments involved fusiform aneurysms saccular aneurysms dissecting aneurysms pseudo-aneurysms Segments involved thoracic thoraco-abdominal abdominal main branches of the aorta iliac arteries Aneurysm Classification Fusiform aneurysm is a cylindrical and symmetrical dilatation that involves the entire circumference of the aortic wall.And is more common than saccular. Saccular aneurysm is more a localized outpouching of only a portion of the aortic wall. Dissecting aneurysm is a hemorrhagic separation of the medial layer of the vessel wall which creates a false lumen. Pseudo or false aneurysm is a well defined collection of blood and connective tissues outside the vessel wall. This may be a consequence of a contained aortic wall rupture from trauma or anastomotic disruption. Aortic aneurysms can also be classified according to the segment involved, thoracic, thoracoabdominal and abdominal (may occur in the branches of the aorta as well. The clinical presentation and treatment depend greatly on their location 5

AAA Sequelae Natural history Complications gradual and/or sporadic expansion accumulation of mural thrombus Complications rupture thromboembolic events compression of adjacent structures

Pathological changes cause the aorta wall to Progression of a AAA Pathological changes cause the aorta wall to become thinner bulge tear rupture

Mean growth rate (cm/yr) Growth rate of AAA Initial size (cm) Mean growth rate (cm/yr) 95% CI 3.0- 3.9 0.39 0.20-0.57 4.0-4.9 0.36 0.21-0.50 5.0-5.9 0.43 0.27-0.60 6.0-6.9 0.64 0.16-1.10 Tan W Abdominal Aortic Aneurysm Rupture www.emedicine.com

Symptoms of AAA rupture Abdominal/back pain Pulsatile abdominal mass Hypotension Clinical triad occurs in only about one-third of cases. ACC/AHA Guidelines on PAD Circulation 2006;113:e463-465.

AAA: risk of rupture Risk of rupture for untreated aneurysm within 5 years (%) 75% 80 70 60 50 40 35% 25% 30 20 10 A review of six case-series including 703 cases of ruptured aneurysm estimated that only 18% of all patients with ruptured AAA reached a hospital and survived surgery. (See Ref 25) 5-5.9cm 6-6.9cm ≥7cm Aneurysm size Simplifed estimates based on various studies Tan W Abdominal Aortic Aneurysm Rupture www.emedicine.com 10

Rupture outcomes Mortality rate can be as high as 80%[1] More than one third of rupture cases die outside the hospital[2] Ruptured AAA Adam. J Vasc Surg 1999;30:922-8. Thomas. Br J Surg Aug 1988

Operative mortality 35-70% for ruptured aneurysm Pae. J Am Surg 2007; Qureshi. Ann Vasc Surg 2007; Greco. J Vasc Surg 2006; Pepplenbosch. J Vasc Surg 2006; Visser. Eur J Vasc Endovasc Surg 2005; Brown. Br J Surg 2002; Heller. J Vasc Surg 2000; Adam. J Vasc Surg 1999; Johansen. J Vasc Surg 1991; Ouriel. J Vasc Surg 1990. 1.0-8.0% for elective AAA cases Qureshi. Ann Vasc Surg 2007; Cowan. Ann NY Acad Sci 2006; Heller. J Vasc Surg 2000; Bradbury. Br J Surg 1998; Blankensteijn. Br J Surg 1998.

ACC/AHA screening high-risk Men ≥ 60 yrs who are siblings or offspring of AAA patients Men 65-75 yrs who have ever smoked Physical exam and ultrasound Class I Class IIa Class IIb Class III ACC/AHA Guidelines on PAD Circulation 2006;113:e463-465.

Diagnosis: physical exam In one study (N=198) 48% of AAA cases were diagnosed clinically physical exam missed 38% of cases detected radiologically Karkos CD. Eur J Vasc Endovasc Surg 2000;19:299-303.

Sensitivity of physical exam Aneurysm diameter Sensitivity 3.0-3.9 cm 29% 4.0-4.9 cm 50% ≥ 5.0 cm 76% Pooled analysis of 15 studies Lederle. JAMA 1999;281:77-82.

Sensitivity of ultrasound Ranges from 82% to 99% Approx 100% in cases with a pulsatile mass In a small proportion of patients, visualization of the aorta inadequate due to obesity, bowel gas, or periaortic disease Quill. Surg Clin North Am 1989;69:713-20.

Ultrasound screening P=0.003 P=0.001 P=0.002 Controlled screening trial of men age 65 to 73 ITT analysis n=6333 screened, n=6306 control Lindholdt. BMJ 2005;330:750. 17

ACC/AHA Guidelines AAA repair Infrarenal/juxtarenal AAA ≥5.5 cm should undergo repair; 4.0-5.4 cm, ultrasound/CT scans every 6-12 mo Repair can be beneficial for infrarenal/juxtarenal AAAs 5.0-6.0 cm Repair probably indicated for suprarenal/type IV thoracoabdominal AA >5.5-6.0cm AAA <4.0cm, ultrasound every 2-3 years is reasonable Intervention not recommended asymptomatic infrarenal/ juxtarenal AAAs <5.0 cm (men) or <4.5 cm (women) Class I Class IIa Class IIb Class III ACC/AHA Guidelines on PAD Circulation 2006;113:e463-465.

Endovascular stent grafting Treatment options Endovascular stent grafting Open surgery

Open repair: advantages Established procedure more than 40 years of clinical experience Excludes aneurysm and prevents sac growth Proven, long-term results

Open surgical repair (OSR): drawbacks Significant incision in the abdomen 30–90 minute cross-clamp Up to 4-hour procedure 1–2 days intensive care 7–14 days hospitalization 4–6 weeks recovery time Open Surgical Repair of AAA Contraindicated in many patients, usually due to advanced age and associated medical problems. The surgery requires a significant incision in the patient’s abdomen. Full-length (xiphoid to pubis) midline incision provides access to the entire abdominal cavity, including the supraceliac aorta and iliac arteries. The aorta is cross clamped for a period of 30-90 minutes. The aneurysm is opened and cleaned of any thrombus and debris. A prosthetic graft of polyester or PTFE is then selected based on the size of the aneurysm and sewn to the aorta, below the renal arteries and above the distal aortoiliac arteries. The wall of the aorta is wrapped and sewn around the graft to protect it. The incision site is then closed with sutures and staples. Surgical repair can take up to four hours to perform. The patient is typically admitted to the intensive care unit for one to two days post-operatively, in addition to seven to 14 days of routine hospitalization. Total recovery time is four to six weeks. Open surgical repair has a reported mortality rate of 2 to 5 %. Complications which include bleeding, bowel ischemia, infection, cardiopulmonary morbidity, and wound problems have been reported as high as 20 %. Emergent surgical treatment for ruptured aneurysm is much more costly, and mortality rates have been reported to vary from 20-90 %, with an average mortality rate of approximately 50 %. See Ref 35-36 21

Contraindications to OSR High anesthesia risk Severely obese Significant cardiac co-morbidities Previous abdominal surgery/hostile abdomen Difficult recovery for patient: risks functional impairment [1] risk of erectile dysfunction [2] 1. Williamson. J Vasc Surg 2001;33:913-920. 2. Lee. Ann Vasc Surg 2000;14:13-19.

Early OSR vs watchful waiting Combined ADAM and UKSAT trials of early/immediate OSR vs surveillance/delayed OSR for AAA < 5.5 cm N = 2226 Endpoint Relative risk 95% CI All cause mortality 1.01 0.77-1.32 Aneurysm-related mortality 0.78 0.56-1.10 Lederle. Ann Intern Med 2007;146:735-741.

Endovascular aneurysm repair (EVAR) Benefits minimally invasive reduced risk of perioperative death faster recovery

AAA repair with stent graft ® Postoperative angiogram Preoperative angiogram 25

EVAR Drawbacks Complications and re-interventions intrasac endoleaks stent graft migration modular dislocation

Endovascular stent grafting Morphology suitable for endovascular repair adequate vascular access appropriate aortic neck length and angulation 27

EVAR vs OSR 30-day outcomes Trial Endpoint EVAR OPEN P EVAR [1] N=1082 ≥ 5.5 cm Mortality 1.7 % 4.7 % 0.009 Secondary interventions 9.8 % 5.8 % 0.02 DREAM [2] N=345 ≥ 5.0 cm 1.2 % 4.6 % 0.1 Mortality & severe complications 1. Lancet 2004;364:843-8. 2. N Engl J Med 2004;351:1607-1618.

EVAR vs OSR 2-year outcomes DREAM Endpoint EVAR OPEN P Survival 89.7% 89.6% 0.86 Survival free of moderate-severe complications 65.6% 65.9% 0.88 Aneurysm-related death 2.1% 5.7% 0.05 N Engl J Med 2005;352:2398-405.

DREAM: sexual dysfunction* Both EVAR and open repair have a negative impact on sexual function in the early postoperative period. After EVAR, recovery to preoperative levels is faster than after open repair. At 3 months, sexual dysfunction levels are similar in both groups. *Measured 5 aspects (interest, pleasure, engagement, orgasm, erection) N=153 Prinssen. J EndovascTher 2004;11:613-620.

Erectile dysfunction Erectile function worsened after open repair (p=0.002) Orgasmic function deteriorated after open repair (p=0.001) Endovascular repair was not accompanied by decreased erectile or orgasmic function (p=0.057 and p=0.068, respectively) Impairment not associated with age, diabetes, or number of patent hypogastric arteries after repair Significant association between impaired erectile function and open aneurysm repair (p=0.036) N=90 Xenos. Ann Vasc Surg 2003;17:530-538.

Agency for Healthcare Research & Quality review of EVAR vs open surgical repair Lower perioperative morbidity and mortality Persistent reduction in AAA-defined mortality to 4 years No improvement in long-term overall survival or health status For AAA ≥ 5.5 cm AHRQ Publication No. 06-E017 August 2006

Medicare cohort 4 yr outcomes Endpoint* EVAR OPEN P Periop mortality 1.2 % 4.8 % <0.001 AAA rupture 1.8 % 0.5 % AAA reintervention 9.0% 1.7% Laparotomy-related Reintervention 4.1% 9.7% Hospitalization 8.1% 14.2% * All 4 yr except perioperative mortality N=22 830 matched patients Schmermerhorn N Engl J Med 2008;358:464-474.

Ongoing studies EVAR vs OSR France Anévrisme de l’aorte abdominale: chirurgie versus endoprothèse (ACE) ClinicalTrials.gov identifier: NCT00224718 US Open versus endovascular repair (OVER) trial for AAA ClinicalTrials.gov identifier: NCT00094575