Abdominal Aortic Aneurysm

3. Abdominal Aortic Aneurysm September 25, 2009

4. Definition • Aneurysm: irreversible dilation of an artery at least 1.5 times its normal caliber • True aneurysm vs. False aneurysm • Varieties: • Degenerative – due to atherosclerosis, most common type • Traumatic – iatrogenic, catheter-related, penetrating trauma • Poststenotic – Bernoulli’s principle, occurs distally (distal to coarctation, distal to cervical rib in thoracic outlet syndrome, etc.) • Dissecting • Mycotic – infected • Anastomotic – separation between graft and native artery

5. Abdominal Aortic Aneurysm • Fusiform dilation of abdominal aorta > 1.5 times its normal diameter • Incidence: 5% of elderly population >60 years old (6-9 times more common in males) • Relative risk: 11.6% in patients with first-degree relative with known AAA • Risk factors: Atherosclerosis, HTN, smoking, male gender, advanced age, connective tissue disease • Risk factors for rupture: diastolic HTN, initially large size at diagnosis, COPD, symptomatic, recent rapid expansion

6. Diagnosis • Exam • Periumbilical palpable pulsatile mass • Ultrasound • Study of choice for initial diagnosis • Used to follow progression of aneurysm over time • Abdominal or back radiographs • Calcifications of aneurysm wall may be seen in ~75% of patients

7. Diagnosis • CT scan • Character, wall thickness, location with respect to renal arteries, presence of leak or rupture • With Contrast for visualization of surrounding vasculature; essential for planning repair • MRI • Greater detail than CT or US regarding lumen, surface anatomy, neck, relationship to renal arteries • Angiogram • Defines vascular anatomy, assess lumen patency and iliac/renal involvement • Especially important in cases of mesenteric ischemia, HTN, renal dysfunction, horseshoe kidney, claudication

8. AAA Screening • U.S. Preventive Services Task Force recommends one-time screening by ultrasonography in men age 65 to 75 years who have ever smoked • No recommendation (for or against) screening in men age 65 to 75 who have never smoked, and an explicit recommendation against routine screening in women, based on the relatively low yield • Repeated screening does not appear to be needed

9. Radiograph

10. Ultrasound

11. Ultrasound

12. Ultrasound

13. CT scan

14. CT with contrast

15. CT with contrast

16. CT Three Dimensional Reconstruction

17. Angiogram

18. Triad of Rupture • Abdominal pain • Pulsatile abdominal mass • Hypotension

19. X-ray

20. CT scan

22. Any Questions?