1. Aortic Aneurysm Tintinalli Chap. 62

2. Epidemiology • Dilation of the abdominal aorta > 3cm and consists of all layer of the aorta • 15,000 deaths annually in the US • 97% occur between the renal arteries and inferior mesenteric artery • Clinically important aneurysms over 4 cm in diameter are present in about 1 percent of men between the ages of 55 and 64; the prevalence increases by 2 to 4 percent per decade thereafter • Smoking is the greatest risk factor for aneuryms (OR 5.07) & also aneurysm growth rate • 5 x more likely in men • CAD & PVD are significant risk factors • HTN is a small risk factor (OR 1.15) • 1st degree blood relative increases odds by 4.3-fold

3. Pathogenesis • Combination of genetic, structural & metabolic factors • Genetic predisposition • Increased levels of elastase/collagnase • Loss of blood vessel elastin • Copper deficiency • Infection (mycotic aneurysms) • Inflammatory disorders • Local Mechanical forces

4. Clinical Presentation • Non-ruptured are usually incidental findings • Two most common findings of recent expansion: abdominal/ back pain & tender to palpation (usually epigastric region) • Pulsatile & tender mass is highly suggestive of recent rupture (found in 77% of ruptures) • Bruits over aorta or femoral arteries • Unequal distal pulses • Presentation mimics numerous common ED diagnoses

5. Diagnosis • Sensitivity of physical examination for the detection of an abdominal aortic aneurysm ranges from 22 to 96 percent • Most non-ruptured aneurysms are incidental findings • Plain abdominal films: 75% have suspicious findings • Aneurysmal calcification, loss of renal shadow, soft tissue mass • Real-time ultrasonography is the preferred modality for screening and for assessing and following abdominal aortic aneurysms since the sensitivity approaches 100 percent, not good at detecting ruptures • CT with contrast: sensitivity around 100% and can detect rupture plus alternative diagnoses

7. Fig. 58-2.

9. Treatment • Mortality rate on elective repair 5% • Mortality rate on emergency repair of ruptured aneurysms 50% • Risk of Rupture (5 cm is the usual surgical cutoff) • Zero in aneurysms less than 4.0 cm in diameter • 0.5 to 5 percent for those 4.0 to 4.9 cm in diameter • 3 to 15 percent for those 5.0 to 5.9 cm in diameter • 10 to 20 percent for those 6.0 to 6.9 cm in diameter • 20 to 40 percent for those 7.0 to 7.9 cm in diameter • 30 to 50 percent for those ≥8.0 cm in diameter

10. Treatment • Indications for surgical intervention • Patients with symptomatic aneurysms should undergo repair, regardless of aneurysm diameter. • Early repair may be beneficial in patients whose aneurysm increases ≥0.5 cm in diameter in six months. • Repair of suprarenal and/or thoracoabdominal aneurysms involves more extensive surgery and greater operative risk. Repair of such aneurysms may be beneficial at diameters >5.5 to 6.0 cm in diameter.

11. Treatment • ED treatment • If suspected rupture • Two large bore Ivs • Type & Cross 10 units • Order ECG • Obtain immediate vascular surgery consultation